mechanical engineering

Steam Power Cycle

2009-06-27T23:11:00.000-07:00

Power plants generate electrical power by using fuels like coal, oil or natural gas. A simple power plant consists of a boiler, turbine, condenser and a pump. Fuel, burned in the boiler and superheater, heats the water to generate steam. The steam is then heated to a superheated state in the superheater. This steam is used to rotate the turbine which powers the generator. Electrical energy is generated when the generator windings rotate in a strong magnetic field. After the steam leaves the turbine it is cooled to its liquid state in the condenser. The liquid is pressurized by the pump prior to going back to the boiler A simple power plant is described by a Rankine Cycle.

Rankine cycle
Saturated or superheated steam enters the turbine at state 1, where it expands isentropically to the exit pressure at state 2. The steam is then condensed at constant pressure and temperature to a saturated liquid, state 3. The heat removed from the steam in the condenser is typically transferred to the cooling water. The saturated liquid then flows through the pump which increases the pressure to the boiler pressure (state 4), where ts1.gif (9k) the water is first heated to the saturation temperature, boiled and typically superheated to state 1. Then the whole cycle is repeated.

Typical Modificationsts
Rehaeat
When steam leaves the turbine, it is typically wet. The presense of water causes erosion of the turbine blades. To prevent this, steam is extracted from high pressure turbine (state 2), and then it is reheated in the boiler (state 2') and sent back to the low pressure turbine.

Regeneration
Regeneration helps improve the Rankine cycle efficiency by preheating the feedwater into the boiler. Regeneration can be achieved by open feedwater heaters or closed feedwater heaters. In open feedwater heaters, a fraction of the steam exiting a high pressure turbine is mixed with the feedwater at the same pressure. In closed system, the steam bled from the turbine is not directly mixed with the feedwater, and therefore, the two streams can be at different pressures.

Air Heating Systems

2008-08-19T00:33:00.000-07:00

It is often convenient to heat buildings with air. Air heating systems may be cost effective if they can be made simple or if they can be combined with ventilation systems. But be aware that due to the low specific heat capacity of air, the use of air for heating purposes is very limited. Large heat loads requires large volumes of air with huge oversized ducts and fans as results. Transporting huge volumes of air also requires a lot of energy.

Required Air Volume in Air Heating Systems

Required air volume in an air heating system can be calculated as
L = Q / (cp ρ (th - tr)) (1)
where
L = air volume (m3/s)
Q = heat loss from the building (kW)
cp = specific heat capacity air - 1.005 (kJ/kgoC)
ρ = density of air - 1.2 (kg/m3)
th = heating air temperature (oC)
tr = room temperature (oC)

As a rule of thumb the heating supply temperature should be in the range 40-50oC. The air flow should be in the range 1-3 times the room volume.

(1) expressed in imperial units:

L = Q / (1.08 (th - tr)) (2)
where
Q = heat (btu/hr)
L = air volume (cfm)
th = heating air temperature (oF)
tr = room temperature (oF)

Air Heating - Temperature Rise Diagram
The diagrams below can be used to estimate heat required to rise temperature in air flows.
SI units - kW, m3/s and deg C
Imperial units - Btu/h, cfm and deg F

1 m3/s = 3,600 m3/h = 35.32 ft3/s = 2,118.9 ft3/min (cfm)
1 kW (kJ/s) = 859.9 kcal/h = 3,413 Btu/h
T(oC) = 5/9[T(oF) - 32]

Example - Heating a single room with air
A building with a large room with heat loss 20 kW is heated with air with maximum temperature 50oC. The room temperature is 20oC. The required air volume can be calculated as

L = 20 / (1.005 1.2 (50 - 20))
= 0.55 m3/s

energy

2008-08-17T01:11:00.000-07:00

Energy is the capacity or capability to do work and energy is used when work are done.

The unit for energy is joule J, where
1 J = 1 Nm

which is the same unit as for work.

Energy forms
There can be several forms of energy, including
* mechanical energy
* heat or thermal energy
* electrical energy
* chemical energy
* nuclear energy
* light energy

Energy Efficiency
Energy efficiency is the ratio between useful energy output and input energy, and can be expressed as

μ = Eo / Ei (1)
where
μ = energy efficiency
Eo = useful energy output
Ei = energy input

It is common to state efficiency as a percentage by multiplying (1) with 100.

Example - Energy Efficiency
A lift moves a mass 10 m up with a force of 100 N. The input energy to the lift is 1500 J. The energy efficiency of the lift can be calculated as
μ = 100 (N) 10 (m) / 1500 (J)
= 0.67 or
= 67 %

Refrigeration Cycle

2008-06-27T22:47:00.000-07:00

Refrigeration is the withdrawl of heat from a substance or space so that temperature lower than that of the natural surroundings is achieved.

Refrigeration may be produced by

thermoelectric means
vapor compression systems
expansion of compressed gases
throttling or unrestrained expansion of gases.

Vapor compression systems are employed in most refrigeration systems. Here, cooling is accomplished by evaporation of a liquid refrigerant under reduced pressure and temperature. The fluid enters the compressors at state 1 where the temperature is elevated by mechanical compression (state 2). The vapor condenses at this pressure, and the resultant heat is dissipated to the surrounding. The high pressure liquid (state 3) then passes through an expansion valve through which the fluid pressure is lowered. The low-pressure fluid enters the evaporator at state 4 where it evaporates by absorbing heat from the refrigerated space, and reenters the compressor. The whole cycle is repeated.

Internal Combustion Engines

2008-06-27T22:39:00.000-07:00

Internal Combustion (IC) engines have completely revolutionized transportation, power generation and have perhaps altered the way the society operates forever. Typical IC engines are classified as Spark and Compression ignition engines.
The simplest model for IC engines is the air-standard model, which assumes that:

The system is closed.
Air is the working fluid and is modeled as an ideal gas throughout the cycle.
Compression and expansion processes are isentropic.
A reversible heat transfer process characterizes the combustion of fuel and air.
Heat rejection takes place reversibly and at constant volume.

The Otto cycle is used to model a basic Spark Ignition engine, while the Diesel cycle is the basic model for the Compression Ignition engine.

Spark Ignition Engines (Otto Cycle)
The spark-ignition engines are the most common type used in cars. Larger engines operate using a four-stroke cycle, while smaller engines operate on a two-stroke cycle. In a simple four-stroke cycle, a combustible mixture of air and fuel is drawn into a cylinder during the intake stroke, and the temperature and pressure of the mixture is raised during the compression stroke. At near the maximum compression, a spark initiates combustion of the mixture, raising its temperature and forcing expansion. The expanding gases do work on the piston during the power stroke and then the burnt gases are purged during the exhaust stroke. Typically 3000 or more such cycles are repeated in a minute.

The Otto cycle is an air-standard model of the actual cycle. In addition to the air-standard assumptions listed above, the combustion process is modelled as a reversible constant volume heat addition process. The four steps of the air-standard Otto cycle are outlined below:

(1-2) Isentropic compression (Compression Stroke)
(2-3) Constant-volume, reversible heat addition (Ignition)
(3-4) Isentropic expansion (Power Stroke)
(4-1) Reversible, constant-volume heat rejection (Exhaust)

Typical pv and Ts diagrams for an Otto cycle are shown below where steps (1-2) and (3-4) are isentropic, and (2-3) and (4-1) are isochoric.

Carbon steels

2008-06-24T01:33:00.001-07:00

Applications of plain carbon steels

These are alloys of iron and carbon, chemically combined, with other elements such as manganese, silicon, sulphur, phosphorus, nickel and chromium. Properties are governed by the amount of carbon and the heat treatment used. Plain carbon steels are broadly classified as: low carbon (0.05-0.3%C), with high ductility and ease of forming; medium carbon (0.3-0.6%C), in which heat treatment can double the strength and hardness but retain good ductility; and high carbon (> 0.6%C), which has great hardness and high strength and is used for tools, dies, springs, etc.

Applications of plain carbon steels :

% Carbon	Name	Applications
0.05	Dead mild	Sheet, strip, car bodies, tinplate, wire, rod, tubes
0.08-0.15	Mild	Sheet, strip, wire, rod, nails, screws, reinforcing bars
0.15	Mild	Case carburizing type
0.10-0.30	Mild	Steel plate, sections, structural steel
0.25-0.40	Medium carbon	Bright drawn bar
0.30-0.45	Medium carbon	High tensile tube, shafts
0.40-0.50	Medium carbon	Shafts, gears, forgings, castings, springs
0.55-0.65	High carbon	Forging dies, springs, railway rails
0.65-0.75	High carbon	Hammers, saws, cylinder liners
0.75-0.85	High carbon	Chisels, die blocks for forging
0.85-0.95	High carbon	Punches, shear blades, high tensile wire
0.95-1.10	High carbon	Knives, axes, screwing taps and dies, milling cutters

Properties of carbon steels (BS 970) :

Type	C (%)	Si (%)	Mn (%)	Tensile strength (Nmm-2)	Elongation (%)	Hardness, BHN*	Applications, etc.
070 M20	0.2	-	0.7	400	21	150	Easily machinable steels suitable for light stressing. Weldable
070 M26	0.26	-	0.7	430	20	165	Stronger than En2. Good machinability. Weldable
080 M30	0.3	-	0.8	460	20	165	Increased carbon improves mechanical properties, but slightly less machinable
080 M36	0.36	-	0.8	490	18	180	Tough steel used for forgings, nuts and bolts, levers, spanners, etc.
080 M40	0.4	-	0.8	510	16	180	Medium carbon steel, readily machinable
080 M46	0.46	-	0.8	540	14	205	Used for motor shafts, axles, brackets and couplings
080 M50	0.5	-	0.8	570	14	205	Used where strength is more important than toughness, e.g. machine tool parts
216 M28	0.28	0.25	1.3	540	10	180	Increased manganese content gives enhanced strength and toughness
080 M15	0.15	0.25	0.8	460	16	-	Case-hardening steel. Used where wear is important, e.g. gears and pawls
060 A96^	0.99-1.0	0.1-0.7	0.5-0.7	1300	-	500	High carbon spring steel

*BHN =Brinell hardness number....^To BS 950.

Tempering temperature and clolour for carbon steels :

Temperature ("C)	Colour	Applications
220	Pale yellow	Hacksaw blades
230	Light yellow	Planing and slotting tools, hammers
240	Straw yellow	Milling cutters, drills, reamers
250	Dark yellow	Taps, dies, shear blades, punches
260	Brown yellow	Wood drills, stone-cutting tools
270	Brown purple	Axe blades, press tools
280	Purple	Cold chisels, wood chisels, plane blades
290	Dark purple	Screw drivers
300	Dark blue	Wood saws, springs
450-700	Up to dark red	Great toughness at expense of hardness

Specific Heat Capacity

2008-06-19T00:51:00.001-07:00

The Specific Heat Capacity is the amount of heat required to change a unit mass of a substance by one degree in temperature. The heat supplied to a unit mass can be expressed as

dQ = m c dt (1)
where
dQ = heat supplied (kJ, Btu)
m = mass (kg, lb)
c = Specific Heat Capacity (kJ/kgoC, Btu/lboF)
dt = temperature change (oC, oF)

Expressing Specific Heat Capacity using (1)
c = dQ / m dt (1b)

Converting between Common Units
* 1 Btu/lbmoF = 4186.8 J/kg K = 1 kcal/kgoC

Specific Heat Capacity Gases
There are two definitions of Specific Heat Capacity for vapors and gases:
cp = (δh/δT)p - Specific Heat Capacity at constant pressure (kJ/kgoC)
cv = ( δh/ δT)v - Specific Heat Capacity at constant volume (kJ/kgoC)

Gas Constant
The gas constant can be expressed as
R = cp - cv (2)
where
R = Gas Constant

Ratio of Specific Heat
The Ratio of Specific Heat Capacities is expressed
k = cp / cv (3)

Calculation Flow Rated in Heating System

2008-06-19T00:46:00.000-07:00

The volumetric flow rate in a heating system can be expressed by the basic equation:

q = h / ( cp ρ dt ) (1)
where
q = volumetric flow rate
h = heat flow rate
cp = specific heat capacity
ρ = density
dt = temperature difference

The basic equation can be modified for the actual units - SI or imperial - and the liquids in use.
Volumetric Water Flow Rate in Imperial Units
For water with temperature 60oF flow rate can be expressed as:
q = h (7.48 gal/ft3) / ((1 Btu/lbm.oF) (62.34 lb/ft3) (60 min/h) dt) (2)
or
q = h / (500 dt) (2b)
where
q = water flow rate (gal/min)
h = heat flow rate (Btu/h)
dt = temperature difference (oF)

For more exact volumetric flow rates for hot water the properties of hot water should be used.
Water Mass Flow Rate in Imperial Units
Water mass flow can be expressed as:
m = h / ((1.2 Btu/lbm.oF) dt) (2c)
where
m = mass flow (lbm/h)

Volumetric Water Flow Rate in SI-Units
For a water heating system the volumetric flow can be expressed in SI-units as:
q = h / ((4.2 kg.oC) (1000 kg/m3) dt) (3)
where
q = water flow rate (m3/s)
h = heat flow rate (kW or kJ/s)
dt = temperature difference (oC)

For more exact volumetric flow rates for hot water the properties of hot water should be used.
Water Mass Flow Rate in SI-units
Mass flow of water can be expressed as:
m = h / ((4.2 kg.oC) dt) (3b)
where
m = mass flow rate (kg/s)

Example - Flow Rate in a Heating System
A water circulating heating systems delivers 230 kW with a temperature difference of 20oC.
The volumetric flow can be expressed as:
q = (230 kW) / ((4.2 kg.oC) (1000 kg/m3) (20oC))
= 2.7 10-3 m3/s
The mass flow can be expressed as:
m = (230 kW) / ((4.2 kJ/kg.oC) (20oC))
= 2.7 kg/s

Types of Geothermal Heat Pump Systems

2008-06-18T23:46:00.000-07:00

There are four basic types of ground loop systems. Three of these—horizontal, vertical, and pond/lake—are closed-loop systems. The fourth type of system is the open-loop option. Which one of these is best depends on the climate, soil conditions, available land, and local installation costs at the site. All of these approaches can be used for residential and commercial building applications.

Closed-Loop Systems
Horizontal
This type of installation is generally most cost-effective for residential installations, particularly for new construction where sufficient land is available. It requires trenches at least four feet deep. The most common layouts either use two pipes, one buried at six feet, and the other at four feet, or two pipes placed side-by-side at five feet in the ground in a two-foot wide trench. The Slinky™ method of looping pipe allows more pipe in a shorter trench, which cuts down on installation costs and makes horizontal installation possible in areas it would not be with conventional horizontal applications.
Vertical
Large commercial buildings and schools often use vertical systems because the land area required for horizontal loops would be prohibitive. Vertical loops are also used where the soil is too shallow for trenching, and they minimize the disturbance to existing landscaping. For a vertical system, holes (approximately four inches in diameter) are drilled about 20 feet apart and 100–400 feet deep. Into these holes go two pipes that are connected at the bottom with a U-bend to form a loop. The vertical loops are connected with horizontal pipe (i.e., manifold), placed in trenches, and connected to the heat pump in the building.
Pond/Lake
If the site has an adequate water body, this may be the lowest cost option. A supply line pipe is run underground from the building to the water and coiled into circles at least eight feet under the surface to prevent freezing. The coils should only be placed in a water source that meets minimum volume, depth, and quality criteria.
Open-Loop System
This type of system uses well or surface body water as the heat exchange fluid that circulates directly through the GHP system. Once it has circulated through the system, the water returns to the ground through the well, a recharge well, or surface discharge. This option is obviously practical only where there is an adequate supply of relatively clean water, and all local codes and regulations regarding groundwater discharge are met.

ASME/ANSI B16 - Standards of Pipes and Fittings

2008-06-18T22:42:00.000-07:00

ASME - American Society of Mechanical Engineers - ASME/ANSI B16 Standards covers pipes and fittings in cast iron , cast bronze, wrought copper and steel.

ASME/ANSI B16.1 - 1998 - Cast Iron Pipe Flanges and Flanged Fittings
This Standard for Classes 25, 125, and 250 Cast Iron Pipe Flanges and Flanged Fittings covers:

(a) pressure-temperature ratings,
(b) sizes and method of designating openings of reducing fittings,
(c) marking,
(d) minimum requirements for materials,
(e) dimensions and tolerances,
(f) bolt, nut, and gasket dimensions and
(g) tests.

ASME/ANSI B16.3 - 1998 - Malleable Iron Threaded Fittings
This Standard for threaded malleable iron fittings Classes 150, and 300 provides requirements for the following:

(a) pressure-temperature ratings
(b) size and method of designating openings of reducing fittings
(c) marking
(d) materials
(e) dimensions and tolerances
(f) threading
(g) coatings

ASME/ANSI B16.4 - 1998 - Cast Iron Threaded Fittings
This Standard for gray iron threaded fittings, Classes 125 and 250 covers:

(a) pressure-temperature ratings
(b) size and method of designating openings of reducing fittings
(c) marking
(d) material
(e) dimensions and tolerances
(f) threading, and
(g) coatings

ASME/ANSI B16.5 - 1996 - Pipe Flanges and Flanged Fittings
The ASME B16.5 - 1996 Pipe Flanges and Flange Fittings standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, testing, and methods of designating openings for pipe flanges and flanged fittings. The standard includes flanges with rating class designations 150, 300, 400, 600, 900, 1500, and 2500 in sizes NPS 1/2 through NPS 24, with requirements given in both metric and U.S units. The Standard is limited to flanges and flanged fittings made from cast or forged materials, and blind flanges and certain reducing flanges made from cast, forged, or plate materials. Also included in this Standard are requirements and recommendations regarding flange bolting, flange gaskets, and flange joints.

ASME/ANSI B16.9 - 2001 - Factory-Made Wrought Steel Buttwelding Fittings
This Standard covers overall dimensions, tolerances, ratings, testing, and markings for wrought factory-made buttwelding fittings in sizes NPS 1/2 through 48 (DN 15 through 1200).

ASME/ANSI B16.10 - 2000 - Face-to-Face and End-to-End Dimensions of Valves
This Standard covers face-to-face and end-to-end dimensions of straightway valves, and center-to face and center-to-end dimensions of angle valves. Its purpose is to assure installation interchangeability for valves of a given material, type size, rating class, and end connection

ASME/ANSI B16.11 - 2001 - Forged Steel Fittings, Socket-Welding and Threaded
This Standard covers ratings, dimensions, tolerances, marking and material requirements for forged fittings, both socket-welding and threaded.

ASME/ANSI B16.12 - 1998 - Cast Iron Threaded Drainage Fittings
This Standard for cast iron threaded drainage fittings covers:

(a) size and method of designating openings in reducing fittings
(b) marking
(c) materials
(d) dimensions and tolerances
(e) threading
(f) ribs
(g) coatings
(h) face bevel discharge nozzles, input shafts, base plates, and foundation bolt holes (see Tables 1 and 2).

ASME/ANSI B16.14 - 1991 - Ferrous Pipe Plugs, Bushings and Locknuts with Pipe Threads
This Standard for Ferrous Pipe Plugs, Bushings, and Locknuts with Pipe Threads covers:

(a) pressure-temperature ratings:
(b) size;
(c) marking;
(d) materials;
(e) dimensions and tolerances;
(f) threading; and
(g) pattern taper.

ASME/ANSI B16.15 - 1985 (R1994) - Cast Bronze Threaded Fittings
This Standard pertains primarily to cast Class 125and Class 250 bronze threaded pipe fittings. Certain requirements also pertain to wrought or cast plugs, bushings, couplings, and caps. This Standard covers:

(a) pressure-temperature ratings;
(b) size and method of designating openings of reducing pipe fittings;
(c) marking;
(d) minimum requirements for casting quality and materials;
(e) dimensions and tolerances in U.S. customary and metric (SI) units;
(f) threading.

ASME/ANSI B16.18 - 1984 (R1994) - Cast Copper Alloy Solder Joint Pressure Fittings
This Standard for cast copper alloy solder joint pressure fittings designed for use with copper water tube, establishes requirements for:

(a) Pressure-temperature ratings;
(b) Abbreviations for end connections;
(c) Sizes and method of designating openings of fittings;
(d) Marking;
(e) Material;
(f) Dimensions and tolerances; and
(g) Tests.

ASME/ANSI B16.20 - 1998 - Metallic Gaskets for Pipe Flanges-Ring-Joint, Spiral-Would, and Jacketed
This standard covers materials, dimensions, tolerances, and markings for metal ring-joint gaskets, spiral-wound metal gaskets, and metal jacketed gaskets and filler material. These gaskets are dimensionally suitable for used with flanges described in the reference flange standards ASME/ANSI B16.5, ASME B16.47, and API-6A. This standard covers spiral-wound metal gaskets and metal jacketed gaskets for use with raised face and flat face flanges. Replaces API-601 or API-601.

ASME/ANSI B16.21 - 1992 - Nonmetallic Flat Gaskets for Pipe Flanges
This Standard for nonmetallic flat gaskets for bolted flanged joints in piping includes:

(a) types and sizes;
(b) materials;
(c) dimensions and allowable tolerances.

ASME/ANSI B16.22 - 1995 - Wrought Copper and Copper Alloy Solder Joint Pressure Fittings
The Standard establishes specifications for wrought copper and wrought copper alloy, solder-joint, seamless fittings, designed for use with seamless copper tube conforming to ASTM B 88 (water and general plumbing systems), B 280 (air conditioning and refrigeration service), and B 819 (medical gas systems), as well as fittings intended to be assembled with soldering materials conforming to ASTM B 32, brazing materials conforming to AWS A5.8, or with tapered pipe thread conforming to ASME B1.20.1. This Standard is allied with ASME B16.18, which covers cast copper alloy pressure fittings. It provides requirements for fitting ends suitable for soldering. This Standard covers:

(a) pressure temperature ratings;
(b) abbreviations for end connections;
(c) size and method of designating openings of fittings;
(d) marking;
(e) material;
(f) dimension and tolerances; and
(g) tests.

ASME/ANSI B16.23 - 1992 - Cast Copper Alloy Solder Joint Drainage Fittings (DWV)
The Standard establishes specifications for cast copper alloy solder joint drainage fittings, designed for use in drain, waste, and vent (DWV) systems. These fittings are designed for use with seamless copper tube conforming to ASTM B 306, Copper Drainage Tube (DWV), as well as fittings intended to be assembled with soldering materials conforming to ASTM B 32, or tapered pipe thread conforming to ASME B1.20.1. This standard is allied with ASME B16.29, Wrought Copper and Wrought Copper Alloy Solder Joint Drainage Fittings - DWV. It provides requirements for fitting ends suitable for soldering. This standard covers:

(a) description;
(b) pitch (slope);
(c) abbreviations for end connections;
(d) sizes and methods for designing openings for reducing fittings;
(e) marking;
(f) material; and
(g) dimensions and tolerances.

ASME/ANSI B16.24 - 1991 (R1998) - Cast Copper Alloy Pipe Flanges and Flanged Fittings
This Standard for Classes 25, 125, 250, and 800 Cast Iron Pipe Flanges and Flanged Fittings covers:

(a) pressure temperature ratings,
(b) sizes and methods of designating openings for reduced fittings,
(c) marking,
(d) minimum requirements for materials,
(e) dimensions and tolerances,
(f) bolt, nut, and gasket dimensions, and
(g) tests.

ASME/ANSI B16.25 - 1997 - Buttwelding Ends

The Standard covers the preparation of butt welding ends of piping components to be joined into a piping system by welding. It includes requirements for welding bevels, for external and internal shaping of heavy-wall components, and for preparation of internal ends (including dimensions and tolerances). Coverage includes preparation for joints with the following.

(a) no backing rings;
(b) split or non continuous backing rings;
(c) solid or continuous backing rings;
(d) consumable insert rings;
(e) gas tungsten are welding (GTAW) of the root pass. Details of preparation for any backing ring must be specified in ordering the component.

ASME/ANSI B16.26 - 1988 - Cast Copper Alloy Fittings for Flared Copper Tubes
This standard for Cast Copper Alloy Fitting for Flared Copper Tubes covers:

(a) pressure rating;
(b) material;
(c) size;
(d) threading;
(e) marking.

ASME/ANSI B16.28 - 1994 - Wrought Steel Buttwelding Short Radius Elbows and Returns
This Standard covers ratings, overall dimensions, testing, tolerances, and markings for wrought carbon and alloy steel buttwelding short radius elbows and returns. The term wrought denotes fittings made of pipe, tubing, plate, or forgings.

ASME/ANSI B16.29 - 1994 - Wrought Copper and Wrought Copper Alloy Solder Joint Drainage Fittings (DWV)
The standard for wrought copper and wrought copper alloy solder joint drainage fittings, designed for use with copper drainage tube, covers:

(a) Description,
(b) Pitch (slope),
(c) Abbreviations for End Connections,
(d) Sizes and Method of Designating Openings for Reducing Fittings,
(e) Marking,
(f) Material,
(g) Dimensions and Tolerances.

ASME/ANSI B16.33 - 1990 - Manually Operated Metallic Gas Valves for Use in Gas Piping Systems Up to 125 psig
General This Standard covers requirements for manually operated metallic valves sizes NPS 1.2 through NPS 2, for outdoor installation as gas shut-off valves at the end of the gas service line and before the gas regulator and meter where the designated gauge pressure of the gas piping system does not exceed 125 psi (8.6 bar). The Standard applies to valves operated in a temperature environment between .20 degrees F and 150 degrees F (.29 degrees C and 66 degrees C). Design This Standard sets forth the minimum capabilities, characteristics, and properties, which a valve at the time of manufacture must possess, in order to be considered suitable for use in gas piping systems.

ASME/ANSI B16.34 - 1996 - Valves - Flanged, Threaded, and Welding End
This standard applies to new valve construction and covers pressure-temperature ratings, dimensions, tolerances, materials, nondestructive examination requirements, testing, and marking for cast, forged, and fabricated flanged, threaded, and welding end, and wafer or flangeless valves of steel, nickel-base alloys, and other alloys shown in Table 1. Wafer or flangeless valves, bolted or through-bolt types, that are installed between flanges or against a flange shall be treated as flanged end valves.

ASME/ANSI B16.36 - 1996 - Orifice Flanges
This Standard covers flanges (similar to those covered in ASME B16.5) that have orifice pressure differential connections. Coverage is limited to the following:

(a) welding neck flanges Classes 300, 400, 600, 900, 1500, and 2500
(b) slip-on and threaded Class 300
Orifice, Nozzle and Venturi Flow Rate Meters

ASME/ANSI B16.38 - 1985 (R1994) - Large Metallic Valves for Gas Distribution
The standard covers only manually operated metallic valves in nominal pipe sizes 2 1/2 through 12 having the inlet and outlet on a common center line, which are suitable for controlling the flow of gas from open to fully closed, for use in distribution and service lines where the maximum gage pressure at which such distribution piping systems may be operated in accordance with the code of federal regulations (cfr), title 49, part 192, transportation of natural and other gas by pipeline; minimum safety standard, does not exceed 125 psi (8.6 bar). Valve seats, seals and stem packing may be nonmetallic.

ASME/ANSI B16.39 - 1986 (R1998) - Malleable Iron Threaded Pipe Unions
This Standard for threaded malleable iron unions, classes 150, 250, and 300, provides requirements for the following:

(a) design
(b) pressure-temperature ratings
(c) size
(d) marking
(e) materials
(f) joints and seats
(g) threads
(h) hydrostatic strength
(i) tensile strength
(j) air pressure test
(k) sampling
(l) coatings
(m) dimensions

ASME/ANSI B16.40 - 1985 (R1994) - Manually Operated Thermoplastic Gas
The Standard covers manually operated thermoplastic valves in nominal sizes 1.2 through 6 (as shown in Table 5). These valves are suitable for use below ground in thermoplastic distribution mains and service lines. The maximum pressure at which such distribution piping systems may be operated is in accordance with the Code of Federal Regulation (CFR) Title 49, Part 192, Transportation of Natural and Other Gas by Pipeline; Minimum Safety Standards, for temperature ranges of .20 deg. F to 100 deg. F (.29 deg. C to 38 deg. C). This Standard sets qualification requirements for each nominal valve size for each valve design as a necessary condition for demonstrating conformance to this Standard. This Standard sets requirements for newly manufactured valves for use in below ground piping systems for natural gas [includes synthetic natural gas (SNG)], and liquefied petroleum (LP) gases (distributed as a vapor, with or without the admixture of air) or mixtures thereof.

ASME/ANSI B16.42 - 1998 - Ductile Iron Pipe Flanges and Flanged Fittings, Classes 150 and 300
The Standard covers minimum requirements for Class 150 and 300 cast ductile iron pipe flanges and flanged fittings. The requirements covered are as follows:

(a) pressure-temperature ratings
(b) sizes and method of designating openings
(c) marking
(d) materials
(e) dimensions and tolerances
(f) blots, nuts, and gaskets
(g) tests

ASME/ANSIB16.44 - 1995 - Manually Operated Metallic Gas Valves for Use in House Piping Systems
This Standard applies to new valve construction and covers quarter turn manually operated metallic valves in sizes NPS 1/2-2 which are intended for indoor installation as gas shutoff valves when installed in indoor gas piping between a gas meter outlet & the inlet connection to a gas appliance.

ASME/ANSI B16.45 - 1998 - Cast Iron Fittings for Solvent Drainage Systems
The Standard for cast iron drainage fittings used on self-aerating, one-pipe Solvent drainage systems, covers the following:

(a) description
(b) sizes and methods for designating openings for reducing fittings
(c) marking
(d) material
(e) pitch
(f) design
(g) dimensions and tolerances
(h) tests

ASME/ANSI B16.47 - 1996 - Large Diameter Steel Flanges: NPS 26 through NPS 60
This Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for pipe flanges in sizes NPS 26 through NPS 60 and in ratings Classes 75, 150,0300, 400, 600, and 900. Flanges may be cast, forged, or plate (for blind flanges only) materials. Requirements and recommendations regarding bolting and gaskets are also included.

ASME/ANSI B16.48 - 1997 - Steel Line Blanks
The Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for operating line blanks in sizes NPS 1/2 through NPS 24 for installation between ASME B16. 5 flanges in the 150, 300, 600, 900, 1500, and 2500 pressure classes.

ASME/ANSI B16.49 - 2000 - Factory-Made Wrought Steel Buttwelding Induction Bends for Transportation and Distribution Systems
This Standard covers design, material, manufacturing, testing, marking, and inspection requirements for factory-made pipeline bends of carbon steel materials having controlled chemistry and mechanical properties, produced by the induction bending process, with or without tangents. This Standard covers induction bends for transportation and distribution piping applications (e.g., ASME B31.4, B31.8, and B31.11) Process and power piping have differing requirements and materials that may not be appropriate for the restrictions and examinations described herein, and therefore are not included in this Standard.

ASME - American Society of Mechanical Engineers

2008-06-18T22:28:00.000-07:00

ASME - American Society of Mechanical Engineers - is a 120,000-member professional organization focused on technical, educational and research issues of the engineering and technology community. ASME conducts one of the world's largest technical publishing operations, holds numerous technical conferences worldwide, and offers hundreds of professional development courses each year. ASME sets internationally recognized industrial and manufacturing codes and standards that enhance public safety.

The work of the Society is performed by its member-elected Board of Governors and through its five Councils, 44 Boards and hundreds of Committees in 13 regions throughout the world.

Technical Divisions and Subdivisions

Advancing the science and practice of mechanical engineering is the responsibility of the Society's 37 Technical Divisions and Subdivisions, which span a vast array of disciplines, technologies and industries:

Advanced Energy Systems - Promotes the advancement of emerging energy conversion devices and processes, such as hydrogen technologies, fuel cells and heat pumps, and understanding of thermo economics.
Aerospace - Concerns mechanical engineering of aircraft and manned/unmanned spacecraft design, including adaptive structures and materials, propulsion systems and life support equipment.
Applied Mechanics - Advances the study of how media, including solids, fluids and systems, respond to external stimuli, as well as the specialized areas of shock and vibration and computer applications.
Bioengineering - Focused on the application of mechanical engineering principles to the conception, design, development, analysis and operation of biomechanical systems.
Computers & Information in Engineering - Concerned with the application of emerging computer simulation technology to enhance the entire engineering process.
Design Engineering - Addresses the design concepts of machines and mechanisms, such as fastening/joining methods and gearing, as well as design aspects affecting reliability and manufacturability.
Dynamic Systems & Control - Concentrates on control methods and devices, from servomechanisms and regulators to automatic controls, for dynamic systems involving forces, motion and/or the flow of energy or material.
Electronic & Photonic Packaging - Fosters cooperation on mechanical engineering considerations of microelectronics, photonics, microwave and microelectromechanical systems design and manufacturing.
Environmental Engineering - Concerns air, ground and water pollution control technologies, including environmental remediation and mixed hazardous/radioactive waste management.
Fluids Engineering - Involved in fluid mechanics in all types of systems and processes involving fluid flow, including pumps, turbines, compressors, pipelines, biological fluid elements and hydraulic structures.
Fluid Power Systems & Technology - Advances the design and analysis of fluid power components, such as hydraulic and pneumatic actuators, pumps, motors and modulating components, in various systems and applications.
Fuels & Combustion Technologies - Dedicated to the understanding of fuels and combustion systems in modern utility and industrial power plants, including fuels handling, preparation, processing and by-product emissions controls.
Heat Transfer - Enhances the theory and application of heat transfer in equipment and thermodynamic processes in all fields of mechanical engineering and related technologies.
Information Storage & Processing Systems - Focuses on the mechanics of electronic information storage devices and their manufacture, with primary focus on rigid and floppy disks, magnetic tape, VCR and optical disk technologies.
Internal Combustion Engine - Furthers mechanical engineering of all types of reciprocating combustion engines, including diesel and spark ignited engines for mobile, marine, rail and stationary power generation applications.
International Gas Turbine Institute - Supports the design, manufacture and operation of gas turbine and aeroengine machinery in various applications, including aircraft, marine and electric power generation.
Management - Concerns the management of the engineering process to control resources, both human and material, to improve the quality of products and services provided by organizations.
Manufacturing Engineering - Fosters the transfer of technology related to manufacturing systems for improved production performance, including machine tools, computer integrated manufacturing and robotics.
Materials - Focuses on the properties of materials, such as metals, ceramics, composites and polymers, and its influence on design consideration in materials selection for engineering structures.
Materials Handling Engineering - Promotes the dissemination and application of technological advancements in material transport systems through mechanical engineering, systems engineering and information technology.
Microelectromechanical Systems Subdivision - Furthers developments of miniature devices combining electrical, mechanical, optical, chemical and/or biological components fabricated via integrated circuit or similar manufacturing techniques.
Noise Control & Acoustics - Advances the application of physical principles of acoustics to the solution of noise control problems, as well as the uses of acoustics in industrial applications.
NonDestructive Evaluation Engineering - Covers the evaluation of critical system components for material/defect/structure characterization through nondestructive methods, such as ultrasonics, radiography and other techniques.
Nuclear Engineering - Concerns the design, development, testing, operation and maintenance of nuclear reactor systems and components, fusion, heat transport, nuclear fuels technology and radioactive waste.
Ocean, Offshore & Arctic Engineering - Promotes international technological progress in the recovery of energy resources in offshore and arctic environments, as well as systems, equipment and vehicles for underwater sea usage.
Petroleum - Covers mechanical systems used in the entire area of petroleum drilling, production, refining, processing, and transportation, as well as management and environmental concerns.
Pipeline Systems Division - Promotes pipeline systems technology, including automation, rotating equipment, geotechnics, heat transfer, offshore, materials, GIS, database, environmental issues, design, construction, and integrity.
Plant Engineering & Maintenance - Focuses on the design, fabrication, installation, operation and maintenance of manufacturing systems, equipment, processes and facilities to create products of enhanced value.
Power - Disseminates information on the research, design, operation, economics, and environmental effects of fossil-fired thermal power generation systems, including hydroelectric.
Pressure Vessels & Piping - Concerns the design, fabrication, inspection, operation and failure prevention of power boilers, heating boilers, pipelines, pumps, valves and other pressure-bearing components and vessels.
Process Industries - Focuses on the design of systems and machines for heating, cooling or treating industrial fluids and gases, including the efficient management and control of the processes themselves.
Rail Transportation - Covers the mechanical design, construction, operation and maintenance of locomotives, freight, passenger and commuter cars in railroads and mass transit systems.
Safety Engineering & Risk Analysis - Promotes practices that lead to reduced risk and loss prevention by creating safer products, processes, and occupational environments.
Solar Energy - Concerned with all aspects of solar-derived energy for mechanical and electrical power generation, as well as wind energy and ocean thermal energy conversion.
Solid Waste Processing - Addresses the design, construction and operation of solid waste processing and disposal facilities, including waste-to-energy combustors, materials recovery/recycling, landfills and composting.
Technology & Society - Covers all issues concerning the inter-relationships between technological innovation and the world community, as well as the social responsibility of the engineer.
Textile Engineering - Focuses on product and process technology for the improvement of fiber, composite material, textile, and apparel manufacturing operations, machinery and instrumentation.
Tribology - Involved in all aspects of friction, lubrication and wear in mechanical designs and manufacturing processes, as well as its economic impact on system reliability and maintainability.

Popular Publications from ASME

The ASME committees within the different divisions and subdivisions develops, updates and publish some of the worlds most used codes and standards. Some of the popular titles are:

ASME 2004 Boiler & Pressure Vessel Code - The Code, which is issued once every three years, is comprised of 28 separate volumes which establish rules of safety governing the design, fabrication and inspection of boilers and pressure vessels, including nuclear power systems. The Code has been updated to incorporate advancements in boiler and pressure vessel design, materials and applications, and provides the latest information to maintain ASME Code Symbol Stamps.
ASME A17-CD - CD-ROM for Elevators and Escalators. Includes: A17.1 Safety Code for Elevators and Escalators - A17.2 Guide for Inspection of Elevators, Escalators and Moving Walks - A17.3 Safety Code for Existing Elevators and Escalators
ASME B31.1 - 2001 Power Piping - The code prescribes minimum requirements for the design, materials, fabrication, erection, test, and inspection of power and auxiliary service piping systems for electric generation stations, industrial institutional plants, central and district heating plants. The code covers boiler external piping for power boilers and high temperature, high pressure water boilers in which steam or vapor is generated at a pressure of more than 15 PSIG; and high temperature water is generated at pressures exceeding 160 PSIG and/or temperatures exceeding 250 degrees F.
ASME B31.3 - 2002 Process Piping - The Code contains rules for piping typically found in petroleum refineries; chemical, pharmaceutical, textile, paper, semiconductor, and cryogenic plants; and related processing plants and terminals. The Code prescribes requirements for materials and components, design, fabrication, assembly, erection, examination, inspection, and testing of piping. The Code applies to piping for all fluids including: (1) raw, intermediate, and finished chemicals; (2) petroleum products; (3) gas, steam, air and water; (4) fluidized solids; (5) refrigerants; and (6) cryogenic fluids. Also included is piping which interconnects pieces or stages within a packaged equipment assembly.
ASME V14.5M - 1994 Dimensioning and Tolerance - The standard establishes uniform practices for stating and interpreting dimensioning, tolerances, and related requirements for use on engineering drawings and in related documents. For a mathematical explanation of many of the principles in this standard, see ASME Y14.5.1m. Practices unique to architectural and civil engineering, land, welding symbology are not included.
ASME B16.5 - 1996 Pipe Flanges and Flange Fittings - The Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, testing, and methods of designating openings for pipe flanges and flanged fittings in sizes NPS 1/2 through NPS 24 and in rating Classes 150, 300, 400, 600, 900, 1500, and 2500. Flanges and flanged fittings may be cast, forged, or (for blind flanges and certain reducing flanges only) plate materials as listed in Table 1A. Requirements and recommendations regarding bolting and gaskets are also included.
ASME B31.4 - 1998 - Pipeline Transportation Systems for Liquid Hydrocarbons and other Liquids - The Code prescribes requirements for the design, materials, construction, assembly, inspection, and testing of piping transporting liquids such as crude oil, condensate, natural gasoline, natural gas liquids, liquefied petroleum gas, carbon dioxide, liquid alcohol, liquid anhydrous ammonia and liquid petroleum products between producers' lease facilities, tank farms, natural gas processing plants, refineries, stations, ammonia plants, terminals (marine, rail and truck) and other delivery and receiving points. Piping consists of pipe, flanges, bolting, gaskets, valves, relief devices, fittings and the pressure containing parts of other piping components. It also includes hangers and supports, and other equipment items necessary to prevent overstressing the pressure containing parts. It does not include support structures such as frames of buildings, buildings stanchions or foundations or any equipment such as defined in para. 400.1.2(B). Requirements for offshore pipelines are found in Chapter IX. Also included within the scope of this Code are: (A) Primary and associated auxiliary liquid petroleum and liquid anhydrous ammonia piping at pipeline terminals (marine, rail and truck), tank farms, pump stations, pressure reducing stations and metering stations, including scraper traps, strainers, and prover loop; (B) Storage and working tanks including pipe-type storage fabricated from pipe and fittings, and piping interconnecting these facilities; (C) Liquid petroleum and liquid anhydrous ammonia piping located on property which has been set aside for such piping within petroleum refinery, natural gasoline, gas processing, ammonia, and bulk plants; (D) Those aspects of operation and maintenance of liquid pipeline systems relating to the safety and protection of the general public, operating company personnel, environment, property and the piping systems.

ASME B31 - Standards of Pressure Piping

2008-06-18T01:46:00.001-07:00

B31 Code for pressure piping, developed by American Society of Mechanical Engineers - ASME, covers Power Piping, Fuel Gas Piping, Process Piping, Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids, Refrigeration Piping and Heat Transfer Components and Building Services Piping. ASME B31 was earlier known as ANSI B31.

B31.1 - 2001 - Power Piping

Piping for industrial plants and marine applications. This code prescribes minimum requirements for the design, materials, fabrication, erection, test, and inspection of power and auxiliary service piping systems for electric generation stations, industrial institutional plants, central and district heating plants.

The code covers boiler external piping for power boilers and high temperature, high pressure water boilers in which steam or vapor is generated at a pressure of more than 15 PSIG; and high temperature water is generated at pressures exceeding 160 PSIG and/or temperatures exceeding 250 degrees F.
B31.2 - 1968 - Fuel Gas Piping

This has been withdrawn as a National Standard and replaced by ANSI/NFPA Z223.1, but B31.2 is still available from ASME and is a good reference for the design of gas piping systems (from the meter to the appliance).
B31.3 - 2002 - Process Piping

Design of chemical and petroleum plants and refineries processing chemicals and hydrocarbons, water and steam. This Code contains rules for piping typically found in petroleum refineries; chemical, pharmaceutical, textile, paper, semiconductor, and cryogenic plants; and related processing plants and terminals.

This Code prescribes requirements for materials and components, design, fabrication, assembly, erection, examination, inspection, and testing of piping. This Code applies to piping for all fluids including: (1) raw, intermediate, and finished chemicals; (2) petroleum products; (3) gas, steam, air and water; (4) fluidized solids; (5) refrigerants; and (6) cryogenic fluids. Also included is piping which interconnects pieces or stages within a packaged equipment assembly.
B31.4 - 2002 - Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids

This Code prescribes requirements for the design, materials, construction, assembly, inspection, and testing of piping transporting liquids such as crude oil, condensate, natural gasoline, natural gas liquids, liquefied petroleum gas, carbon dioxide, liquid alcohol, liquid anhydrous ammonia and liquid petroleum products between producers' lease facilities, tank farms, natural gas processing plants, refineries, stations, ammonia plants, terminals (marine, rail and truck) and other delivery and receiving points.

Piping consists of pipe, flanges, bolting, gaskets, valves, relief devices, fittings and the pressure containing parts of other piping components. It also includes hangers and supports, and other equipment items necessary to prevent overstressing the pressure containing parts. It does not include support structures such as frames of buildings, buildings stanchions or foundations

Requirements for offshore pipelines are found in Chapter IX. Also included within the scope of this Code are:

(A) Primary and associated auxiliary liquid petroleum and liquid anhydrous ammonia piping at pipeline terminals (marine, rail and truck), tank farms, pump stations, pressure reducing stations and metering stations, including scraper traps, strainers, and prover loop;
(B) Storage and working tanks including pipe-type storage fabricated from pipe and fittings, and piping interconnecting these facilities;
(C) Liquid petroleum and liquid anhydrous ammonia piping located on property which has been set aside for such piping within petroleum refinery, natural gasoline, gas processing, ammonia, and bulk plants;
(D) Those aspects of operation and maintenance of liquid pipeline systems relating to the safety and protection of the general public, operating company personnel, environment, property and the piping systems.

B31.5 - 2001 - Refrigeration Piping and Heat Transfer Components

This Code prescribes requirements for the materials, design, fabrication, assembly, erection, test, and inspection of refrigerant, heat transfer components, and secondary coolant piping for temperatures as low as -320 deg F (-196 deg C), whether erected on the premises or factory assembled, except as specifically excluded in the following paragraphs.

Users are advised that other piping Code Sections may provide requirements for refrigeration piping in their respective jurisdictions.

This Code shall not apply to:

(a) any self- contained or unit systems subject to the requirements of Underwriters Laboratories or other nationally recognized testing laboratory:
(b) water piping;
(c) piping designed for external or internal gage pressure not exceeding 15 psi (105 kPa) regardless of size; or
(d) pressure vessels, compressors, or pumps,

but does include all connecting refrigerant and secondary coolant piping starting at the first joint adjacent to such apparatus.
B31.8 - 2003 - Gas Transmission and Distribution Piping Systems

This Code covers the design, fabrication, installation, inspection, and testing of pipeline facilities used for the transportation of gas. This Code also covers safety aspects of the operation and maintenance of those facilities.
B31.8S-2001 - 2002 - Managing System Integrity of Gas Pipelines

This Standard applies to on-shore pipeline systems constructed with ferrous materials and that transport gas.

Pipeline system means all parts of physical facilities through which gas is transported, including pipe, valves, appurtenances attached to pipe, compressor units, metering stations, regulator stations, delivery stations, holders and fabricated assemblies.

The principles and processes embodied in integrity management are applicable to all pipeline systems. This Standard is specifically designed to provide the operator (as defined in section 13) with the information necessary to develop and implement an effective integrity management program utilizing proven industry practices and processes.

The processes and approaches within this Standard are applicable to the entire pipeline system.
B31.9 - 1996 - Building Services Piping

This Code Section has rules for the piping in industrial, institutional, commercial and public buildings, and multi-unit residences, which does not require the range of sizes, pressures, and temperatures covered in B31.1.

This Code prescribes requirements for the design, materials, fabrication, installation, inspection, examination and testing of piping systems for building services. It includes piping systems in the building or within the property limits.
B31.11 - 2002 - Slurry Transportation Piping Systems

Design, construction, inspection, security requirements of slurry piping systems.

Covers piping systems that transport aqueous slurries of no hazardous materials, such as coal, mineral ores and other solids between a slurry processing plant and the receiving plant.
B31G - 1991 - Manual for Determining Remaining Strength of Corroded Pipelines

A supplement To B31 Code-Pressure Piping

ASTM International - Standards for Steel Pipes, Tubes and Fittings

2008-06-18T00:58:00.001-07:00

The ASTM International specifications for steel tubes list standard requirements for boiler and super heater tubes, general service tubes, steel tubes in refinery service, heat exchanger and condenser tubes, mechanical and structural tubing.
Steel Pipes

A53 - A53/A53M-99b - Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless
A74 - A74-98 - Specification for Cast Iron Soil Pipe and Fittings
A106 - A106-99e1 - Specification for Seamless Carbon Steel Pipe for High-Temperature Service
A126 - A126-95e1 - Specification for Grey Iron Castings for Valves, Flanges, and Pipe Fittings
A134 - A134-96 - Specification for Pipe, Steel, Electric-Fusion (Arc)-Welded (Sizes NPS 16 and Over)
A135 - A135-97c - Specification for Electric-Resistance-Welded Steel Pipe
A139 - A139-96e1 - Specification for Electric-Fusion (Arc)-Welded Steel Pipe (NPS 4 and Over)
A182 - A182/A182M-99 - Specification for Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service
A252 - A252-98 - Specification for Welded and Seamless Steel Pipe Piles
A312 - A312/A312M-00 - Specification for Seamless and Welded Austenitic Stainless Steel Pipes
A333 - A333/A333M-99 - Specification for Seamless and Welded Steel Pipe for Low-Temperature Service
A335 - A335/A335M-99 - Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
A338 - A338-84 (1998) - Specification for Malleable Iron Flanges, Pipe Fittings, and Valve Parts for Railroad, Marine, and Other Heavy Duty Service at Temperatures Up to 650ï¿½F (345ï¿½C)
A358 - A358/A358M-98 - Specification for Electric-Fusion-Welded Austenitic Chromium-Nickel Alloy Steel Pipe for High-Temperature Service
A369 - A369/A369M-92 - Specification for Carbon and Ferritic Alloy Steel Forged and Bored Pipe for High-Temperature Service
A376 - A376/A376M-98 - Specification for Seamless Austenitic Steel Pipe for High-Temperature Central-Station Service
A377 - A377-99 - Index of Specifications for Ductile-Iron Pressure Pipe
A409 - A409/A409M-95ae1 - Specification for Welded Large Diameter Austenitic Steel Pipe for Corrosive or High-Temperature Service
A426 - A426-92 (1997) - Specification for Centrifugally Cast Ferritic Alloy Steel Pipe for High-Temperature Service
A451 - A451-93 (1997) - Specification for Centrifugally Cast Austenitic Steel Pipe for High-Temperature Service
A523 - A523-96 - Specification for Plain End Seamless and Electric-Resistance-Welded Steel Pipe for High-Pressure Pipe-Type Cable Circuits
A524 - A524-96 - Specification for Seamless Carbon Steel Pipe for Atmospheric and Lower Temperatures
A530 - A530/A530M-99 - Specification for General Requirements for Specialized Carbon and Alloy Steel Pipe
A648 - A648-95e1 - Specification for Steel Wire, Hard Drawn for Pre-stressing Concrete Pipe
A674 - A674-95 - Practice for Polyethylene Encasement for Ductile Iron Pipe for Water or Other Liquids
A691 - A691-98 - Specification for Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at High Temperatures
A694 - A694/A694M-00 - Specification for Carbon and Alloy Steel Forgings for Pipe Flanges, Fittings, Valves, and Parts for High-Pressure Transmission Service
A716 - A716-99 - Specification for Ductile Iron Culvert Pipe
A733 - A733-99 - Specification for Welded and Seamless Carbon Steel and Austenitic Stainless Steel Pipe Nipples
A742 - A742/A742M-98 - Specification for Steel Sheet, Metallic Coated and Polymer Pre-coated for Corrugated Steel Pipe
A746 - A746-99 - Specification for Ductile Iron Gravity Sewer Pipe
A760 - A760/A760M-99 - Specification for Corrugated Steel Pipe, Metallic-Coated for Sewers and Drains
A761 - A761/A761M-98 - Specification for Corrugated Steel Structural Plate, Zinc-Coated, for Field-Bolted Pipe, Pipe-Arches, and Arches
A762 - A762/A762M-98 - Specification for Corrugated Steel Pipe, Polymer Pre-coated for Sewers and Drains
A790 - A790/A790M-99 - Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe
A796 - A796/A796M-99 - Practice for Structural Design of Corrugated Steel Pipe, Pipe-Arches, and Arches for Storm and Sanitary Sewers and Other Buried Applications
A798 - A798/A798M-97a - Practice for Installing Factory-Made Corrugated Steel Pipe for Sewers and Other Applications
A807 - A807/A807M-97 - Practice for Installing Corrugated Steel Structural Plate Pipe for Sewers and Other Applications
A810 - A810-94 - Specification for Zinc-Coated (Galvanized) Steel Pipe Winding Mesh
A813 - A813/A813M-95e2 - Specification for Single- or Double-Welded Austenitic Stainless Steel Pipe
A814 - A814/A814M-96 (1998) - Specification for Cold-Worked Welded Austenitic Stainless Steel Pipe
A849 - A849-99 - Specification for Post-Applied Coatings, Pavings, and Linings for Corrugated Steel Sewer and Drainage Pipe
A861 - A861-94e1 - Specification for High-Silicon Iron Pipe and Fittings
A862 - A862/A862M-98 - Practice for Application of Asphalt Coatings to Corrugated Steel Sewer and Drainage Pipe
A865 - A865-97 - Specification for Threaded Couplings, Steel, Black or Zinc-Coated (Galvanized) Welded or Seamless, for Use in Steel Pipe Joints
A872 - A872-91 (1997) - Specification for Centrifugally Cast Ferritic/Austenitic Stainless Steel Pipe for Corrosive Environments
A885 - A885/A885M-96 - Specification for Steel Sheet, Zinc and Aramid Fiber Composite Coated for Corrugated Steel Sewer, Culvert, and Underdrain Pipe
A888 - A888-98e1 - Specification for Hubless Cast Iron Soil Pipe and Fittings for Sanitary and Storm Drain, Waste, and Vent Piping Applications
A926 - A926-97 - Test Method for Comparing the Abrasion Resistance of Coating Materials for Corrugated Metal Pipe
A928 - A928/A928M-98 - Specification for Ferritic/Austenitic (Duplex) Stainless Steel Pipe Electric Fusion Welded with Addition of Filler Metal
A929 - A929/A929M-97 - Specification for Steel Sheet, Metallic-Coated by the Hot-Dip Process for Corrugated Steel Pipe
A930 - A930-99 - Practice for Life-Cycle Cost Analysis of Corrugated Metal Pipe Used for Culverts, Storm Sewers, and Other Buried Conduits
A943 - A943/A943M-95e1 - Specification for Spray-Formed Seamless Austenitic Stainless Steel Pipes
A949 - A949/A949M-95e1 - Specification for Spray-Formed Seamless Ferritic/Austenitic Stainless Steel Pipe
A954 - A954-96 - Specification for Austenitic Chromium-Nickel-Silicon Alloy Steel Seamless and Welded Pipe
A972 - A972/A972M-99 - Specification for Fusion Bonded Epoxy-Coated Pipe Piles
A978 - A978/A978M-97 - Specification for Composite Ribbed Steel Pipe, Precoated and Polyethylene Lined for Gravity Flow Sanitary Sewers, Storm Sewers, and Other Special Applications
A984 - A984/A984M-00 - Specification for Steel Line Pipe, Black, Plain-End, Electric-Resistance-Welded
A998 - A998/A998M-98 - Practice for Structural Design of Reinforcements for Fittings in Factory-Made Corrugated Steel Pipe for Sewers and Other Applications
A999 - A999/A999M-98 - Specification for General Requirements for Alloy and Stainless Steel Pipe
A1005 - A1005/A1005M-00 - Specification for Steel Line Pipe, Black, Plain End, Longitudinal and Helical Seam, Double Submerged-Arc Welded
A1006 - A1006/A1006M-00 - Specification for Steel Line Pipe, Black, Plain End, Laser Beam Welded

Steel Tubes

Superheater, Boiler and Miscellaneous Tubes:

A178 - A178/A178M-95 - Specification for Electric-Resistance-Welded Carbon Steel and Carbon-Manganese Steel Boiler and Superheater Tubes
A179 - A179/A179M-90a (1996) e1 - Specification for Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes
A192 - A192/A192M-91 (1996) e1 - Specification for Seamless Carbon Steel Boiler Tubes for High-Pressure Service
A209 - A209/A209M-98 - Specification for Seamless Carbon-Molybdenum Alloy-Steel Boiler and Superheater Tubes
A210 - A210/A210M-96 - Specification for Seamless Medium-Carbon Steel Boiler and Superheater Tubes
A213 - A213/A213M-99a - Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes
A249 - A249/A249M-98e1 - Specification for Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes
A250 - A250/A250M-95 - Specification for Electric-Resistance-Welded Ferritic Alloy-Steel Boiler and Superheater Tubes
A254 - A254-97 - Specification for Copper-Brazed Steel Tubing
A268 - A268/A268M-96 - Specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service
A269 - A269-98 - Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service
A270 - A270-98ae1 - Specification for Seamless and Welded Austenitic Stainless Steel Sanitary Tubing
A334 - A334/A334M-99 - Specification for Seamless and Welded Carbon and Alloy-Steel Tubes for Low-Temperature Service
A423 - A423/A423M-95 - Specification for Seamless and Electric-Welded Low-Alloy Steel Tubes
A450 - A450/A450M-96a - Specification for General Requirements for Carbon, Ferritic Alloy, and Austenitic Alloy Steel Tubes
A608 - A608-91a (1998) - Specification for Centrifugally Cast Iron-Chromium-Nickel High-Alloy Tubing for Pressure Application at High Temperatures
A618 - A618-99 - Specification for Hot-Formed Welded and Seamless High-Strength Low-Alloy Structural Tubing
A632 - A632-98 - Specification for Seamless and Welded Austenitic Stainless Steel Tubing (Small-Diameter) for General Service
A688 - A688/A688M-98 - Specification for Welded Austenitic Stainless Steel Feedwater Heater Tubes
A771 - A771/A771M-95 - Specification for Seamless Austenitic and Martensitic Stainless Steel Tubing for Liquid Metal-Cooled Reactor Core Components
A778 - A778-98 - Specification for Welded, Unanneled Austenitic Stainless Steel Tubular Products
A789 - A789/A789M-00 - Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service
A803 - A803/A803M-98 - Specification for Welded Ferritic Stainless Steel Feedwater Heater Tubes
A822 - A822-90 (1995) e1 - Specification for Seamless Cold-Drawn Carbon Steel Tubing for Hydraulic System Service
A826 - A826/A826M-95 - Specification for Seamless Austenitic and Martensitic Stainless Steel Duct Tubes for Liquid Metal-Cooled Reactor Core Components
A847 - A847-99a - Specification for Cold-Formed Welded and Seamless High Strength, Low Alloy Structural Tubing with Improved Atmospheric Corrosion Resistance
A908 - A908-91 (1998) - Specification for Stainless Steel Needle Tubing
A953 - A953-96 - Specification for Austenitic Chromium-Nickel-Silicon Alloy Steel Seamless and Welded Tubing -

Heat-Exchanger and Condenser Tubes

A179 - A179/A179M-90a (1996) e1 - Specification for Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes
A213 - A213/A213M-99a - Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes
A214 - A214/A214M-96 - Specification for Electric-Resistance-Welded Carbon Steel Heat-Exchanger and Condenser Tubes
A249 - A249/A249M-98e1 - Specification for Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes
A498 - A498-98 - Specification for Seamless and Welded Carbon, Ferritic, and Austenitic Alloy Steel Heat-Exchanger Tubes with Integral Fins
A851 - A851-96 - Specification for High-Frequency Induction Welded, Unannealed, Austenitic Steel Condenser Tubes -

Structural Tubing

A500 - A500-99 - Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes
A501 - A501-99 - Specification for Hot-Formed Welded and Seamless Carbon Steel Structural Tubing
A847 - A847-99a - Specification for Cold-Formed Welded and Seamless High Strength, Low Alloy Structural Tubing with Improved Atmospheric Corrosion Resistance
A618 - A618-99 - Specification for Hot-Formed Welded and Seamless High-Strength Low-Alloy Structural Tubing -

Mechanical Tubing

A511 - A511-96 - Specification for Seamless Stainless Steel Mechanical Tubing
A512 - A512-96 - Specification for Cold-Drawn Buttweld Carbon Steel Mechanical Tubing
A513 - A513-98 - Specification for Electric-Resistance-Welded Carbon and Alloy Steel Mechanical Tubing
A519 - A519-96 - Specification for Seamless Carbon and Alloy Steel Mechanical Tubing
A554 - A554-98e1 - Specification for Welded Stainless Steel Mechanical Tubing -

Welded Fittings

A234 - A234/A234M-99 - Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
A403 - A403/A403M-99a - Specification for Wrought Austenitic Stainless Steel Piping Fittings
A420 - A420/A420M-99 - Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low-Temperature Service
A758 - A758/A758M-98 - Specification for Wrought-Carbon Steel Butt-Welding Piping Fittings with Improved Notch Toughness
A774 - A774/A774M-98 - Specification for As-Welded Wrought Austenitic Stainless Steel Fittings for General Corrosive Service at Low and Moderate Temperatures -

ASTM international Standart pipe

2008-06-18T00:54:00.001-07:00

ASTM International, originally known as the American Society for Testing and Materials (ASTM), is one of the largest voluntary standards development organizations in the world - a trusted source for technical standards for materials, products, systems, and services.

The standards includes test procedures for determining or verifying characteristics as chemical composition, measuring performance. The standards cover refined materials as steel and basic products as machinery and fabricated equipment.

The ASTM standards are published in a set of 67 volumes in 16 sections:

Volume 00.01 - Subject Index - Alphanumeric List

Section 1 - Iron and Steel Products

Volume 01.01 - Steel - Piping, Tubing, Fittings
Volume 01.02 - Ferrous Castings; Ferroalloys
Volume 01.03 - Steel - Plate, Sheet, Strip, Wire; Stainless Steel Bar
Volume 01.04 - Steel - Structural, Reinforcing, Pressure Vessel, Railway
Volume 01.05 - Steel - Bars, Forgings, Bearing, Chain, Springs
Volume 01.06 - Coated Steel Products
Volume 01.07 - Ships and Marine Technology
Volume 01.08 - Fasteners

Section 2 - Nonferrous Metal Products

Volume 02.01 - Copper and Copper Alloys
Volume 02.02 - Aluminum and Magnesium Alloys
Volume 02.03 - Electrical Conductors
Volume 02.04 - Metals: Nickel, Cobalt, Lead, Tin, Zinc, Cadmium, Precious, Reactive, Refractory Metals and Alloys; Materials for Thermostats, Electrical Testing and Resistance, Contacts, Connectors
Volume 02.05 - Metallic and Inorganic Coatings; Metal Powders; Sintered P/M Structural Parts

Section 3 - Metals Test Methods and Analytical Procedures

Volume 03.01 - Metals - Mechanical Testing; Elevated and Low-Temperature Tests; Metallography
Volume 03.02 - Wear and Erosion; Metal Corrosion
Volume 03.03 - Nondestructive Testing
Volume 03.04 - Magnetic Properties
Volume 03.05 - Analytical Chemistry for Metals, Ores, and Related Materials (I): E 32 to E 1724
Volume 03.06 - Analytical Chemistry for Metals, Ores, and Related Materials (II): E356 to latest; Molecular Spectroscopy; Surface Analysis

Section 4 - Construction

Volume 04.01 - Cement, Lime; Gypsum
Volume 04.02 - Concrete and Aggregates
Volume 04.03 - Road and Paving Materials; Vehicle-Pavement Systems
Volume 04.04 - Roofing and Waterproofing
Volume 04.05 - Roofing, Waterproofing, and Bituminous Materials
Volume 04.06 - Thermal Insulation; Environmental Acoustics
Volume 04.07 - Building Seals and Sealants; Fire Standards; Dimension Stone
Volume 04.08 - Soil and Rock (I): D 420 to D 5779
Volume 04.09 - Soil and Rock (II): D 5780 - latest; Geosynthetics
Volume 04.10 - Wood
Volume 04.11 - Building Construction
Volume 04.12 - Building Constructions (II): E 1672 - latest; Property Management Systems
Volume 04.13 - Geosynthetics

Section 5 - Petroleum Products, Lubricants, and Fossil Fuels

Volume 05.01 - Petroleum Products and Lubricants (I): D 56 - D 2596
Volume 05.02 - Petroleum Products and Lubricants (II): D 2597 - D 4927
Volume 05.03 - Petroleum Products and Lubricants (III): D 4928 - D 5950
Volume 05.04 - Petroleum Products and Lubricants (IV): D 5966 - latest
Volume 05.05 - Test Methods for Rating Motor, Diesel, and Aviation Fuels; Catalysts; Manufactured Carbon and Graphite Products
Volume 05.06 - Gaseous Fuels; Coal and Coke

Section 6 - Paints, Related Coatings, and Aromatics

Volume 06.01 - Paint - Tests for Chemical, Physical, and Optical Properties; Appearance
Volume 06.02 - Paint - Products and Applications; Protective Coatings; Pipeline Coatings
Volume 06.03 - Paint - Pigments, Drying Oils, Polymers, Resins, Naval Stores, Cellulosic Esters, and Ink Vehicles
Volume 06.04 - Paint - Solvents; Aromatic Hydrocarbons

Section 7 - Textiles

Volume 07.01 - Textiles (I): D76 - D3218
Volume 07.02 - Textiles (II): D3333 - latest

Section 8 - Plastics

Volume 08.01 - Plastics (I): D 256 - D 2343
Volume 08.02 - Plastics (II): D 2383 - D 4322
Volume 08.03 - Plastics (III): D 4329 - latest
Volume 08.04 - Plastic Pipe and Building Products

Section 9 - Rubber

Volume 09.01 - Rubber, Natural and Synthetic -- General Test Methods; Carbon Black
Volume 09.02 - Rubber Products, Industrial - Specifications and Related Test Methods: Gaskets; Tires

Section 10 - Electrical Insulation and Electronics

Volume 10.01 - Electrical Insulation (I): D 69 - D 2484
Volume 10.02 - Electrical Insulation (II): D 2518 - latest
Volume 10.03 - Electrical Insulating Liquids and Gases; Electrical Protective Equipment
Volume 10.04 - Electronics

Section 11 - Water and Environmental Technology

Volume 11.01 - Water (I)
Volume 11.02 - Water (II)
Volume 11.03 - Atmospheric Analysis; Occupational Health and Safety; Protective Clothing
Volume 11.04 - Environmental Assessment; Hazardous Substances and Oil Spill Responses; Waste Management
Volume 11.05 - Biological Effects and Environmental Fate; Biotechnology; Pesticides

Section 12 - Nuclear, Solar, and Geothermal Energy

Volume 12.01 - Nuclear Energy (I)
Volume 12.02 - Nuclear Energy (II), Solar, and Geothermal Energy

Section 13 - Medical Devices and Services

Volume 13.01 - Medical Devices; Emergency Medical Services
Volume 13.02 - Emergency Medical Services, Search and Rescue

Section 14 - General Methods and Instrumentation

Volume 14.01 - Healthcare Informatics
Volume 14.02 - General Test Methods; Forensic Sciences; Terminology; Conformity Assessment; Statistical Methods
Volume 14.03 - Temperature Measurement
Volume 14.04 - Laboratory Apparatus; Degradation of Materials; SI; Oxygen Fire Safety

Section 15 - General Products, Chemical Specialties, and End Use Products

Volume 15.01 - Refractures; Activated Carbon; Advanced Ceramics
Volume 15.02 - Glass; Ceramic Whitewares
Volume 15.03 - Space Simulation; Aerospace and Aircraft; High Modulus Fibers
Volume 15.04 - Soaps and Other Detergents; Polishes; Leather; Resilient Floor Coverings
Volume 15.05 - Engine Coolants; Halogenated Organic Solvents and Fire Extinguishing Agents; Industrial and Specialty Chemicals
Volume 15.06 - Adhesives
Volume 15.07 - Sport Equipment; Safety and Traction for Footwear; Amusement Rides; Consumer Products
Volume 15.08 - Sensory Evaluation; Vacuum Cleaners; Security Systems; Detention Facilities; Food Service Equipment
Volume 15.09 - Paper; Packaging; Flexible Barrier Materials; Business Imaging Products

Geothermal Heat Pumps

2008-06-18T00:36:00.001-07:00

The geothermal heat pump, also known as the ground source heat pump, is a highly efficient renewable energy technology that is gaining wide acceptance for both residential and commercial buildings. Geothermal heat pumps are used for space heating and cooling, as well as water heating. Its great advantage is that it works by concentrating naturally existing heat, rather than by producing heat through combustion of fossil fuels. The technology relies on the fact that the Earth (beneath the surface) remains at a relatively constant temperature throughout the year, warmer than the air above it during the winter and cooler in the summer, very much like a cave. The geothermal heat pump takes advantage of this by transferring heat stored in the Earth or in ground water into a building during the winter, and transferring it out of the building and back into the ground during the summer. The ground, in other words, acts as a heat source in winter and a heat sink in summer. The system includes three principal components:

• Geothermal earth connection subsystem
• Geothermal heat pump subsystem
• Geothermal heat distribution subsystem.

Earth Connection
Using the Earth as a heat source/sink, a series of pipes, commonly called a "loop," is buried in the ground near the building to be conditioned. The loop can be buried either vertically or horizontally. It circulates a fluid (water, or a mixture of water and antifreeze)
that absorbs heat from, or relinquishes heat to, the surrounding soil, depending on whether the ambient air is colder or warmer an the soil.

Heat Pump
For heating, a geothermal heat pump removes the heat from the fluid in the Earth connection, concentrates it, and then transfers it to the building. For cooling, the process is reversed.
Heat Distribution
Conventional ductwork is generally used to distribute heated or cooled air from the geothermal heat pump throughout the building.
Residential Hot Water In addition to space conditioning, geothermal heat pumps can be used to provide domestic hot water when the system is operating. Many residential systems are now equipped with desuperheaters that transfer excess heat from the geothermal heat pump's compressor to the house's hot water tank. A desuperheater provides no hot water during the spring and fall when the geothermal heat pump system is not operating; however, because the geothermal heat pump is so much more efficient than other means of water heating, manufacturers are beginning to offer "full demand" systems that use a separate
heat exchanger to meet all of a household's hot water needs. These units cost-effectively provide hot water as quickly as any competing system.

Specific Speed - Pumps

2008-06-17T02:59:00.000-07:00

Specific speed is a number characterizing the type of impeller in a unique and coherent manner. Specific speed are determined independent of pump size and can be useful comparing different pump designs. The specific speed identifies the geometrically similarity of pumps.

Specific speed is dimensionless and are expressed as
Ns = ω q1/2 / h3/4 (1)
where
Ns = specific speed
ω = pump shaft rotational speed (rpm)
q = flow rate (m3/h, l/s, m3/min, US gpm, British gpm) at Best Efficiency Point (BEP)
h = head rise (m, ft)
Note! When comparing pumps and their documentation be aware of the units used.

Typical values for specific speed - Ns - for different designs in US units (gpm)

radial flow - 500 <>
mixed flow - 2000 <>
axial flow - 7000 < Ns < 20000 - typical for propellers and axial fans

Convert between US units (gpm) and Metric units (m3/h)

Ns (US) = 1.63 Ns (metric)
Ns (Metric) = 0.614 Ns (US)
Ns (Metric) = 0.67 Ns (British)

Example - Specific Speed for a Pump
A pump has a capacity of 1500 gal/min at 100 ft of head and is rotating at 1760 rev/min. Specific speed can be expressed as:
Nsd = (1760 rev/min) (1500 gal/min)1/2 / (100 ft)3/4
= 2156 - a typical centrifugal pump

Centrifugal Pumps and Standards

2008-06-17T01:29:00.000-07:00

Standards of design and dimensional specifications are necessary to bring unity to centrifugal pumps. Standards are provided by organizations like

ISO - International Standards Organizations
API - American International Institute
ANSI - American National Standards Institute
DIN - Deutsches Institut f�r Normung
NPFA - National Fire Protection Agency
BSi - British Standards institute

Some commonly used centrifugal pumps standards

ANSI/API 610-1995 - Centrifugal Pumps for General Refinery Service - Covers the minimum requirements for centrifugal pumps, including pumps running in reverse as hydraulic power recovery turbines, for use in petroleum, heavy duty chemicals, and gas industry services. The pump types covered by this standard can be broadly classified as overhung, between bearings, and vertically suspended.
DIN EN ISO 5199 - Technical specifications for centrifugal pumps
ASME B73.1-2001 - Specification for Horizontal End Suction Centrifugal Pumps for Chemical Process - This standard covers centrifugal pumps of horizontal, end suction single stage, centerline discharge design. This Standard includes dimensional interchangeability requirements and certain design features to facilitate installation and maintenance. It is the intent of this Standard that pumps of the same standard dimension designation from all sources of supply shall be interchangeable with respect to mounting dimensions, size and location of suction and discharge nozzles, input shafts, baseplates, and foundation bolt holes
ASME B73.2-2003 - Specifications for Vertical In-Line Centrifugal Pumps for Chemical Process
BS 5257:1975 - Specification for horizontal end-suction centrifugal pumps (16 bar) - Principal dimensions and nominal duty point. Dimensions for seal cavities and base plate installations.

centrifugal pimps

2008-06-17T01:24:00.000-07:00

A centrifugal pump converts the input power to kinetic energy in the liquid by accelerating the liquid by a revolving device - an impeller. The most common type is the volute pump. Fluid enters the pump through the eye of the impeller which rotates at high speed. The fluid is accelerated radially outward from the pump chasing. A vacuum is created at the impellers eye that continuously draws more fluid into the pump.

The energy created by the pump is kinetic energy according the Bernoulli Equation. The energy transferred to the liquid corresponds to the velocity at the edge or vane tip of the impeller. The faster the impeller revolves or the bigger the impeller is, the higher will the velocity of the liquid energy transferred to the liquid be. This is described by the Affinity Laws.

Pressure and Head
If the discharge of a centrifugal pump is pointed straight up into the air the fluid will pumped to a certain height - or head - called the shut off head. This maximum head is mainly determined by the outside diameter of the pump's impeller and the speed of the rotating shaft. The head will change as the capacity of the pump is altered.

The kinetic energy of a liquid coming out of an impeller is obstructed by creating a resistance in the flow. The first resistance is created by the pump casing which catches the liquid and slows it down. When the liquid slows down the kinetic energy is converted to pressure energy.

it is the resistance to the pump's flow that is read on a pressure gauge attached to the discharge line

A pump does not create pressure, it only creates flow. Pressure is a measurement of the resistance to flow.

In Newtonian fluids (non-viscous liquids like water or gasoline) the term head is used to measure the kinetic energy which a pump creates. Head is a measurement of the height of the liquid column the pump creates from the kinetic energy the pump gives to the liquid.

the main reason for using head instead of pressure to measure a centrifugal pump's energy is that the pressure from a pump will change if the specific gravity (weight) of the liquid changes, but the head will not

The pump's performance on any Newtonian fluid can always be described by using the term head.
Different Types of Pump Head

Total Static Head - Total head when the pump is not running
Total Dynamic Head (Total System Head) - Total head when the pump is running
Static Suction Head - Head on the suction side, with pump off, if the head is higher than the pump impeller
Static Suction Lift - Head on the suction side, with pump off, if the head is lower than the pump impeller
Static Discharge Head - Head on discharge side of pump with the pump off
Dynamic Suction Head/Lift - Head on suction side of pump with pump on
Dynamic Discharge Head - Head on discharge side of pump with pump on

The head is measured in either feet or meters and can be converted to common units for pressure as psi or bar.

it is important to understand that the pump will pump all fluids to the same height if the shaft is turning at the same rpm

The only difference between the fluids is the amount of power it takes to get the shaft to the proper rpm. The higher the specific gravity of the fluid the more power is required.

Centrifugal Pumps are "constant head machines"

Note that the latter is not a constant pressure machine, since pressure is a function of head and density. The head is constant, even if the density (and therefore pressure) changes.

The head of a pump in metric units can be expressed in metric units as:
h = (p2 - p1)/(ρ g) + v22/(2 g) (1)
where
h = total head developed (m)
p2 = pressure at outlet (N/m2)
p1 = pressure at inlet (N/m2)
ρ = density (kg/m3)
g = acceleration of gravity (9,81) m/s2
v2 = velocity at the outlet (m/s)

Head described in simple terms

a pump's vertical discharge "pressure-head" is the vertical lift in height - usually measured in feet or m of water - at which a pump can no longer exert enough pressure to move water. At this point, the pump may be said to have reached its "shut-off" head pressure. In the flow curve chart for a pump the "shut-off head" is the point on the graph where the flow rate is zero

classification of pumps

2008-06-17T01:18:00.000-07:00

Pumps are in general classified as Centrifugal Pumps (or Roto-dynamic pumps) and Positive Displacement Pumps.
Centrifugal Pumps (Roto-dynamic pumps)

The centrifugal or roto-dynamic pump produce a head and a flow by increasing the velocity of the liquid through the machine with the help of a rotating vane impeller. Centrifugal pumps include radial, axial and mixed flow units.

Centrifugal pumps can further be classified as

* end suction pumps
* in-line pumps
* double suction pumps
* vertical multistage pumps
* horizontal multistage pumps
* submersible pumps
* self-priming pumps
* axial-flow pumps
* regenerative pumps

Positive Displacement Pumps

The positive displacement pump operates by alternating of filling a cavity and then displacing a given volume of liquid. The positive displacement pump delivers a constant volume of liquid for each cycle against varying discharge pressure or head.

The positive displacement pump can be classified as:

* Reciprocating pumps - piston, plunger and diaphragm
* Power pumps
* Steam pumps
* Rotary pumps - gear, lobe, screw, vane, regenerative (peripheral) and progressive cavity

Selecting between Centrifugal or Positive Displacement Pumps

Selecting between a Centrifugal Pump or a Positive Displacement Pump is not always straight forward.
Flow Rate and Pressure Head

The two types of pumps behave very differently regarding pressure head and flow rate:

* The Centrifugal Pump has varying flow depending on the system pressure or head
* The Positive Displacement Pump has more or less a constant flow regardless of the system pressure or head. Positive Displacement pumps generally gives more pressure than Centrifugal Pump's.

Capacity and Viscosity

Another major difference between the pump types is the effect of viscosity on the capacity:

* In the Centrifugal Pump the flow is reduced when the viscosity is increased
* In the Positive Displacement Pump the flow is increased when viscosity is increased

Liquids with high viscosity fills the clearances of a Positive Displacement Pump causing a higher volumetric efficiency and a Positive Displacement Pump is better suited for high viscosity applications. A Centrifugal Pump becomes very inefficient at even modest viscosity.
Mechanical Efficiency

The pumps behaves different considering mechanical efficiency as well.

* Changing the system pressure or head has little or no effect on the flow rate in the Positive Displacement Pump
* Changing the system pressure or head has a dramatic effect on the flow rate in the Centrifugal Pump

Net Positive Suction Head - NPSH

Another consideration is the Net Positive Suction Head NPSH.

* In a Centrifugal Pump, NPSH varies as a function of flow determined by pressure
* In a Positive Displacement Pump, NPSH varies as a function of flow determined by speed. Reducing the speed of the Positive Displacement Pump pump, reduces the NPSH

Energy Transfer Equation

2008-06-17T00:51:00.000-07:00

he energy transfer of a substance can be expressed as
Q = m cp dt (1)
where
Q = quantity of energy transferred (kJ)
m = mass of substance (kg)
cp = specific heat capacity of the substance (kJ/kgoC)
dt = temperature difference (rise or fall) in the substance (oC)

Third Law of Thermodynamics

2008-06-17T00:49:00.000-07:00

The First Law of Thermodynamics forms the
* basis for quantitative analysis of chemical reactions
The Second Law of Thermodynamics is used to
* identify the directions of chemical reactions
The Third Law of Thermodynamics states that
* the entropy of any pure substance in thermodynamic equilibrium approaches zero as the temperature approaches zero (Kelvin), or conversely
* the temperature (Kelvin) of any pure substance in thermodynamic equilibrium approaches zero when the entropy approaches zero

The Third Law of Thermodynamics can mathematically be expressed as
lim ST→0 = 0 (1)
where
S = entropy (J/K)
T = absolute temperature (K)

At a temperature of absolute zero there is no thermal energy or heat. At a temperature of zero Kelvin the atoms in a pure crystalline substance are aligned perfectly and do not move. There is no entropy of mixing since the substance is pure.

The temperature of absolute zero is the reference point for determination entropy. The absolute entropy of a substance can be calculated from measured thermodynamic properties by integrating the differential equations of state from absolute zero. For a gas this requires integrating through solid, liquid and gaseous phases.

2nd Law of Thermodynamics

2008-06-17T00:44:00.000-07:00

here are two classical statements of the second law of thermodynamics:

Kelvin & Planc
"No (heat) engine whose working fluid undergoes a cycle can absorb heat from a single reservoir, deliver an equivalent amount of work, and deliver no other effect"

Clausius
"No machine whose working fluid undergoes a cycle can absorb heat from one system, reject heat to another system and produce no other effect"

Both statements of the second law place constraints on the first law by identifying that energy goes downhill.

The second law is concerned with entropy (S), which is a measure of disorder at the microscopic level. Entropy is produced by all processes and associated with the entropy production is the loss of ability to do work. The second law says that the entropy of the universe increases. An increase in overall disorder is therefore spontaneous. If the volume and energy of a system are constant, then every change to the system increases the entropy. If volume or energy change, then the entropy of the system actually decrease. However, the entropy of the universe does not decrease.

For energy to be available there must be a region with high energy level and a region with low energy level. Useful work must be derived from the energy that would flows from the high level to the low level.

* 100% of the energy can not be transformed to work
* Entropy can be produced but never destroyed

Efficiency of a heat machine

The efficiency of a heat machine working between two energy levels is defined in terms of absolute temperature:
η = ( Th - Tc ) / Th = 1 - Tc / Th(1)
where
η = efficiency
Th = temperature high level (K)
Tc = temperature low level (K)

As a consequence, to attain maximum efficiency the Tc would have to be as cold as possible. For 100% efficiency the Tc would have to equal 0 K. This is practically impossible, so the efficiency is always less than 1 (less than 100%).
Change in entropy > 0, irreversible process
Change in entropy = 0, reversible process
Change in entropy < 0, impossible process

Entropy is used to define the unavailable energy in a system. Entropy defines the relative ability of one system to act to an other. As things moves toward a lower energy level, where one is less able to act upon the surroundings, the entropy is said to increase.

* For the universe as a whole the entropy is increasing!

Entropy definition
Entropy is defined as :
S = H / T (2)
where
S = entrophy (kJ/kg K)
H = enthalpy (kJ/kg)
T = absolute temperature (K)

A change in the entropy of a system is caused by a change in its heat content, where the change of entropy is equal to the heat change divided by the average absolute temperature (Ta):
dS = dH / Ta (3)
The sum of (H / T) values for each step in the Carnot cycle equals 0. This only happens because for every positive H there is a countering negative H, overall.

Carnot Heat Cycle
In a heat engine, a gas is reversibly heated and then cooled. A model of the cycle is as follows: State 1 --(isothermal expansion) --> State 2 --(adiabatic expansion) --> State 3 --(isothermal compression) --> State 4 --(adiabatic compression) --> State 1

State 1 to State 2: Isothermal Expansion
Isothermal expansion occurs at a high temperature Th, dT = 0 and dE1 = 0. Since dE = H + w, w1 = - H1. For ideal gases, dE is dependent on temperature only.

State 2 to State 3: Adiabatic Expansion
The gas is cooled from the high temperature, Th, to the low temperature, Tc. dE2 = w2 and H2 = 0 (adiabatic).

State 3 to State 4: Isothermal Compression
This is the reverse of the process between states 1 and 2. The gas is compressed at Tc. dT = 0 and dE3 = 0. w3 = - H3

State 4 to State 1: Adiabatic Compression
This is the reverse of the process between states 2 and 3. dE4 = w4 and H4 = 0 (adiabatic).
The processes in the Carnot cycle can be graphed as the pressure vs. the volume. The area enclosed in the curve is then the work for the Carnot cycle because w = - integral (P dV). Since this is a cycle, dE overall equals 0. Therefore,
-w = H = H1 + H2 + H3 + H4
If you decrease Tc, then the quantity -w gets larger in magnitude.
if -w > 0 then H > 0 and the system, the heat engine, does work on the surroundings.

The laws of thermodynamics were determined empirically (by experiment). They are generalizations of repeated scientific experiments. The second law is a generalization of experiments dealing with entropy--it is that the dS of the system plus the dS of the surroundings is equal to or greater then 0.

* Entropy is not conserved like energy!

Example - Entropy Heating Water
A process raises 1 kg of water from 0 to 100oC (273 to 373 K) under atmospheric conditions.
Specific enthalpy at 0oC (hf) = 0 kJ/kg (from steam tables) (Specific - per unit mass)
Specific enthalpy of water at 100oC (hf) = 419 kJ/kg (from steam tables)
Change in specific entropy:
dS = dH / Ta
= (419 - 0) / ((273 + 373)/2)
= 1.297 kJ/kgK

Example - Entropy Evaporation Water to Steam
A process changes 1 kg of water at 100oC (373 K) to saturated steam at 100oC (373 K) under atmospheric conditions.
Specific enthalpy of steam at 100oC (373 K) before evaporating = 0 kJ/kg (from steam tables)
Specific enthalpy of steam at 100oC (373 K) after evaporating = 2 258 kJ/kg (from steam tables)

Change in specific entropy:
dS = dH / Ta
= (2 258 - 0) / ((373 + 373)/2)
= 6.054 kJ/kgK

The total change in specific entropy from water at 0oC to saturated steam at 100oC is the sum of the change in specific entropy for the water, plus the change of specific entropy for the steam.
Example - Entropy Superheated Steam

A process superheats 1 kg of saturated steam at atmospheric pressure to 150oC (423 K).
Specific total enthalpy of steam at 100oC (373 K) = 2 675 kJ/kg (from steam tables)
Specific total enthalpy of superheated steam at 150oC (373 K) = 2 777 kJ/kg (from steam tables)
Change in specific entropy:
dS = dH / Ta
= (2 777 - 2 675) / ((423 + 373)/2)
= 0.256 kJ/kgK

* Entropy table for superheated steam

1st Law of Thermodynamics

2008-06-17T00:36:00.000-07:00

he 1st Law of Thermodynamics tells us that energy is neither created nor destroyed, thus the energy of the universe is a constant. However, energy can certainly be transferred from one part of the universe to another. To work out thermodynamic problems we will need to isolate a certain portion of the universe, the system, from the remainder of the universe, the surroundings.

The energy transfer between different systems can be expressed as:
E1 = E2 (1)
where
E1 = initial energy
E2 = final energy

The internal energy encompasses:
* The kinetic energy associated with the motions of the atoms
* The potential energy stored in the chemical bonds of the molecules
* The gravitational energy of the system

The first law is the starting point for the science of thermodynamics and for engineering analysis.
Based on the types of exchange that can take place we will define three types of systems:
* isolated systems: no exchange of matter or energy
* closed systems: no exchange of matter but some exchange of energy
* open systems: exchange of both matter and energy

The first law makes use of the key concepts of internal energy, heat, and system work. It is used extensively in the discussion of heat engines.

Internal Energy - Internal energy is defined as the energy associated with the random, disordered motion of molecules. It is separated in scale from the macroscopic ordered energy associated with moving objects; it refers to the invisible microscopic energy on the atomic and molecular scale. For example, a room temperature glass of water sitting on a table has no apparent energy, either potential or kinetic . But on the microscopic scale it is a seething mass of high speed molecules. If the water were tossed across the room, this microscopic energy would not necessarily be changed when we superimpose an ordered large scale motion on the water as a whole.
Heat - Heat may be defined as energy in transit from a high temperature object to a lower temperature object. An object does not possess "heat"; the appropriate term for the microscopic energy in an object is internal energy. The internal energy may be increased by transferring energy to the object from a higher temperature (hotter) object - this is called heating.
Work - When work is done by a thermodynamic system, it is usually a gas that is doing the work. The work done by a gas at constant pressure is W = p dV, where W id work, p is pressure and dV is change in volume.
For non-constant pressure, the work can be visualized as the area under the pressure-volume curve which represents the process taking place.
Heat Engines -Refrigerators, Heat pumps, Carnot cycle, Otto cycle

The change in internal energy of a system is equal to the head added to the system minus the work done by the system:
dE = Q - W (2)
where
dE = change in internal energy
Q = heat added to the system
W = work done by the system

1st law does not provide the information of direction of processes and does not determine the final equilibrium state. Intuitively, we know that energy flows from high temperature to low temperature. Thus, the 2nd law is needed to determine the direction of processes.

Enthalpy is the "thermodynamic potential" useful in the chemical thermodynamics of reactions and non-cyclic processes. Enthalpy is defined by
H = U + PV (3)
where
H = enthalpy
U = internal energy
P = pressure
V = volume

Enthalpy is then a precisely measurable state variable, since it is defined in terms of three other precisely definable state variables.

Entropy is used to define the unavailable energy in a system. Entropy defines the relative ability of one system to act to an other. As things moves toward a lower energy level, where one is less able to act upon the surroundings, the entropy is said to increase. Entropy is connected to the Second Law of Thermodynamics.

For the universe as a whole the entropy is increasing.

air conditioner efficiency

2008-06-16T23:05:00.000-07:00

he cooling equipment systems used in residential and small commercial buildings often express cooling system efficiency in terms of the Energy Efficiency Ratio (EER) and/or Seasonal Energy Efficiency Ratio (SEER).

These are defined by the cooling effect in Btu (not in tons) divided by the power use in watts (not in kW) for the peak day (EER), or the seasonal average day (SEER).

For room air conditioners, the commonly used efficiency ratio is the

EER - Energy Efficiency Ratio

For central air conditioners, it the ratio used is

SEER - Seasonal Energy Efficiency Ratio

These ratings are posted on the Energy Guide Label, which shall be attached to all new air conditioners.

Some of the air conditioner manufacturers participate in the voluntary EnergyStar labeling program where EnergyStar-labeled appliances mean that they have high EER and SEER ratings.
EER - Energy Efficiency Ratio

Room air conditioners in general range from 5,000 Btu per hour to 15,000 Btu per hour. Select room air conditioners with EER of at least 9.0 for mild climates. In a hot climates, select air conditioners with EER over 10.
SEER - Seasonal Energy Efficiency Ratio

For central air conditioners there is units with SEERs reaching nearly 17.
Example - EER

A cooling unit operating at 1 kW/ton would have an EER of 12,000 Btu divided by 1000 watts or 12. This is mathematically equivalent to multiplying the COP by 3.413. Therefore a small cooling unit operating at 1 kW (1000 watts) per ton is equivalent to a COP of 3.516, or an EER of 12.

cooling heating equations

2008-06-16T23:02:00.000-07:00

Sensible Heat

The sensible heat in a heating or cooling process of air can be expressed as
hs = 1.08 q dt (1)
where
hs = sensible heat (btu/hr)
q = air volume flow (cfm, cubic feet per minute)
dt = temperature difference (oF)

Latent Heat
The latent heat due to moisture in the air can be expressed as:
hl = 0.68 q dwgr (2)
or
hl = 4,840 q dwlb (3)
where
hl= latent heat (btu/hr)
q = air volume flow (cfm, cubic feet per minute)
dwgr = humidity ratio difference (gram water/lb dry air)
dwlb = humidity ratio difference (lb water/lb dry air)

Total Heat - Latent and Sensible Heat
Total heat due to both temperature and moisture can be expressed as:
ht = 4.5 q dh (4)
where
ht= total heat (btu/hr)
q = air volume flow (cfm, cubic feet per minute)
dh = enthalpy difference (btu/lb dry air)

Total heat can also be expressed as:
ht = hs + hl
= 1.08 q dt + 0.68 q dwgr (4)

Example - Heating Air

An air flow of one cfm is heated from 32 to 52oF. Using (1) the sensible heat added to the air can be expressed as:
hs = 1.08 1(cfm) (52 - 32)(oF)
= 21.6 (btu/hr)

Chilled-Water System

2008-06-16T22:56:00.000-07:00

In a chilled-water system the air conditioner cools water to between 40 and 45oF (4 and 7oC). The chilled water is distributed throughout the building in a piping system and connected to air condition cooling units wherever needed.
Total Heat Removed

The total heat removed by air condition chilled-water installation can be expressed as

h = 500 q dt (1)
where
h = total heat removed (Btu/h)
q = water flow rate (gal/min)
dt = temperature difference (oF)

Evaporator Flow Rate
The evaporator water flow rate can be expressed as
qe = htons 24 / dt (2)
where
qe = evaporator water flow rate (gal/min)
htons = air condition cooling load (tons)

Condenser Flow Rate
The condenser water flow rate can be expressed as
qc = htons 30 / dt (2)
where
qc = condenser water flow rate (gal/min)
htons = air condition cooling load (tons)

hydroulics force

2008-06-16T22:45:00.000-07:00

The force produced by a double acting hydraulic piston on the rod side can be expressed as

F1 = π / 4 (d22 - d12) P1 (1)
where
F1 = rod pull force (lb)
d1 = rod diameter (inches)
d2 = piston diameter (inches)
P1 = pressure in the cylinder (rod side) (lff/in)

The force produced opposite the rod can be expressed as
F2 = π / 4 d22 P2 (2)
where
F2 = rod push force (lb)
P2 = pressure in the cylinder (opposite rod) (lff / in)

The diagram below indicates the rod pushing force for cylinders with different diameters and pressures.

Right Hand Rule for Torque

2008-06-16T03:26:00.000-07:00

Torque is inherently a vector quantity. Part of the torque calculation is the determination of direction. The direction is perpendicular to both the radius from the axis and to the force. It is conventional to choose it in the right hand rule direction along the axis of rotation. The torque is in the direction of the angular velocity which would be produced by it in the absence of other influences. In general, the change in angular velocity is in the direction of the torque.

Compression Ignition Engine (Diesel Cycle)

2008-06-10T23:39:00.000-07:00

Compression Ignition engines are mostly used in marine applications, power generation and heavier transportation vehicles. Here, in a typical four-stroke cycle, air is drawn into the cylinder in the intake stroke and then compressed during the Compression Stroke. At near maximum compression, finely atomized diesel fuel is sprayed into the hot air, initiating auto-ignition of the mixture. During the subsequent power stroke, the expanding hot mixture does work on the piston, then the burnt gases are purged during the exhaust stroke.

The Diesel Cycle is an air-standard model of the actual cycle described above. The Diesel Cycle differs from the Otto Cycle only in the modeling of the combustion process: In a Diesel Cycle, it is assumed to occur as a reversible constant pressure heat addition process, while in an Otto Cycle, the volume is assumed constant. The four steps of the air-standard Diesel Cycle are outlined below:

(1-2) Isentropic Compression (Compression Stroke)
(2-3) Reversible, constant pressure heat addition (Ignition)
(3-4) Isentropic expansion to initial volume (Power Stroke)
(4-1) Reversible constant-volume heat rejection (Exhaust)

Typical pv and Ts diagrams for Diesel Cycle are shown below where steps (1-2) and (3-4) are Isentropic and step (2-3) is Isobaric while (4-1) is Isochoric

Alternating Pumps

2008-06-01T18:11:00.000-07:00

Critical systems should always be equipped with more than one pump. Choosing between the installation of one or more backup pumps depends on the costs of the installation and

how critical the operation of the system is - a water supply system for a hospital is more critical than a chilled water cooling systems for homes.
the delivery and installation time of a new pump.

If two or more pumps are used, the operation between the pumps should be systematically altered to achieve equal wear.
Alternatives for Alternating Pumps

Pumps can be systematically altered by

manual alteration - where the operator selects the lead pump and the sequence of the lag pumps.
duty alternation - where the lead pump change every time the pump or system is stopped.
timed alternation - where the lead pump is switched by a timer or clock.
equal run time - where the lead pump is switched to achieve the same operating time for each pump.

Note! Running an automatic system for equalizing the wear of the pumps

has the advantage of extending the time before repair and reinvestments.
has the disadvantage that all pumps may wear out on at the same time - reducing the operation safety for the whole system.

Spring materials

2008-05-30T03:03:00.000-07:00

Carbon steels

Hard-drawn spring steel
Low cost; general purpose; low stress; low fatigue life. Temperatures below 120°C. Tensile strength up to 1600 N mm -2.
Piano (music) wire
Tougher than harddrawn spring steel; high stress (tensile strength up to 2300 N inm- *); long fatigue life; used for 'small springs'. Temperatures below 120°C.
Oil-tempered spring steel
General purpose springs; stress not too high; unsuitable for shock or impact loads. Popular diameter range 3-15 mm.

Alloy steels

Chrome-vanadium steel
Best for shock and impact loaL,. Available in oiltempered and annealed condition. Used for internal combustion engine valve spriags. Temperatures up to 220 "C.
Silicon-manganese steel
High working stress; used for leaf springs; temperatures up to 220°C. Si1 icon-chromium steel Better than silicon-manganese; temperatures up to 220 "C.
Stainless steels
Cold drawn; tensile strength up to 1200Nmm-2. Temperatures from sub-zero to 290 "C, depending on type. Diameters up to 5mm.

Non-ferrous alloys

Spring brass (70/30)
Low strength, but cheap and easily formed. Good electrical conductivity.
Phosphor bronze (5%Sn)
High strength, resilience, corrosion resistance and fatigue strength. Good electrical conductivity. Tensile strength 770N mm-2. Wire diameters 0.15-7mm. Used for leaf and coil switch springs.
Beryllium-copper (2 1/4%)
Formed in soft condition and hardened. High tensile strength. Used for current-carrying brush springs and contacts. Tensile strength 1300Nmm-2.
Inconel
Nickel based alloy useful up to 370°C. Exceedingly good corrosion resistance. Diameters up to 7mm. Tensile strength up to 1300Nmm-2.

Moduli of spring materials

Material	Modulus of rigidity, G, GNm-2	Modulus of elasticity, E,GNm-2
Carbon steel	80	207
Chromevanadium steel	80	207
1818 Stainless steel	63	193
70130 Brass	38	103
Phosphor bronze	36	97
Beryllium copper	40-48	110-128
Inconel	76	214
Monel	66	179
Nickel-silver38	38	110

Cast irons

2008-05-29T21:56:00.000-07:00

Grey iron
Grey iron is so called because of the colour of the fracture face. It contains 1.543% carbon and 0.3-5% silicon plus manganese, sulphur and phosphorus. It is brittle with low tensile strength, but is easy to cast.

Properties of some grey irons (BS 1452)

Grade	Tensile strength (Nmm-2)	Compressive strength (Nmm-2)	Transverse strength (Nmm-2)	Hardness, BHN*	Modulus of elasticity (GN m-2)
10	160	620	290-370	160-180	76-104
17	260	770	450-490	190-250	110-130
24	370	1240	620-700	240-300	124-145

Spheroidal graphite (SG) iron

This is also called nodular iron because the graphite is in the form of small spheres or nodules. These result in higher ductility which can be improved further by heat treatment. Mechanical properties approach those of steel combined with good castability.

Properties of some SG irons (BS 2789)

Grade	Tensile strength (Nmm-2)	0.5% permanent set stress (Nmm-2)	Hardness, BHN*	Minimum elongation (%)
SNG24/17	370	230	140-170	17
SNG37/2	570	390	210-310	2
SNG47/2	730	460	280-450	2

Malleable irons

These have excellent machining qualities with strength similar to grey irons but better ductility as a result of closely controlled heat treatment. There are three types: white heart with superior casting properties; black heart with superior machining properties; and pearlitic which is superior to the other two but difficult to produce.

Properties of some maUeabie irons

Type	Grade	Minimum Tensile strength (Nmm-2)	Yield Point strength (Nmm-2)	Hardness, BHN*	elongation (%)
White heart, BS 309	W22/24	310-340	180-200	248(max.)	4
White heart, BS 309	W24/8	340-370	200-220	248(max)	6
Black heart, BS 310	B18/6	280	170	150(max)	6
Black heart, BS 310	B20/10	310	190	150(max)	10
Black heart, BS 310	B22/14	340	200	150(max)	14
Pearlitic, BS 3333	P28/6	430	-	143-187	6
Pearlitic, BS 3333	P33/4	460	-	170-229	4

* BHN : Brinell Hardness Number

Metal processes

2008-05-28T21:02:00.000-07:00

Metals can be processed in a variety of ways. These can be classified roughly into casting, forming and machining. The following table gives characteristics of different processes for metals, although some may also apply to non-metallic materials such as plastics and composites.

General characteristics of metal processes :

Process	Economic quantity	Materials (typical)	Optimum Size	Minimum section (mm)	Holes Possible	Inserts possible
Sand casting	Small/barge	No limit	1-100 kg	3	yes	yes
Die casting, gravity	large	AI, Cu, Mg,Zn alloys	1- 50 kg	3	yes	yes
Die casting, pressure	large	AI, Cu, Mg,Zn alloys	50g-50kg	1	yes	yes
Centrifugal casting	large	No limit	30mm-1m diameter	3	yes	yes
Investment casting	small/large	No limit	50g-50kg	1	yes	yes
Closed die forging	large	No limit	3000cm3	3	yws	yes
Hot extrusion	large	No limit	500mm diameter	1	-	yes
Hot rolling	large	No limit	-	-	no	no
Cold rolling	large	No limit	-	-	no	no
Drawing	small/large	AI,Cu,Zn,mild steel	3mm/6m diameter	0.1	no	yes
Spinning	one-off, large	AI,Cu,Zn,mild steel	6m/4.5m diameter	0.1	no	yes
Impact extrusion	large	AI, Pb, Zn,Mg, Sn	6-100mm diameter	0.1	-	no
Sintering	large	Fe, W, bronze	80g-4kg	0.5	yes	yes
Machining	one-off, large	No limit	-	-	yes	yes

Non-ferrous metals

2008-05-28T01:54:00.000-07:00

Electrolytically refined copper (99.95% Pure) is used for components requiring high conductivity. Less Pure copper is used for chemical plant, domestic plumbing, etc. Copper is available in the form ofwire, sheet, strip, plate, round bar and tube. Copper is used in many alloys, including brasses, bronzes, aluminium bronze, cupronickel, nickel-silver and bryllium-copper.

Composition and mechanical properties of some copper alloys

Type and uses	Cu (%)	Zn (%)	Other	Condition	0.1 proof stress (N mm-2)	Tensile strength (N mm-2)	Elongation (%)	Vickers hardness
Muntz metal: die tampings, and extrusions	60	40	-	Extruded	110	350	40	75
Free-cutting brass: high-peed machining	58	39	3 Pb	Extruded	140	440	30	100
Cartridge brass: severe cold working	70	30	-	Annealed	75	270	70	65
				Work hardened	500	600	5	180
Standard brass: presswork	65	35	-	Annealed	90	320	65	65
				Work hardened	500	690	4	185
Admiralty gunmetal: general-purpose castings	88	2	10 Sn	Sand casting	120	290	16	85
Phosphor bronze: castings and bushes for bearings	remainder	remainder	10 Sn 0.03-0.25 P	Sand casting	120	280	15	90

Alloy steels

2008-05-28T01:53:00.000-07:00

Classification
Alloy steels differ from carbon steels in that they contain a high proportion of other alloying elements. The following are regarded as the minimum levels:

Element	%	Element	%	Element	%
Aluminium	0.3	Lead	0.1	Silicon	2.0
Chromium	0.5	Manganese and silica	2.0	Sulphur and phosphorus	0.2
Cobalt	0.3	Molybdenum	0.1	Tungsten	0.3
Copper	0.4	Nickel	0.5	Vanadium	0.1

Alloy steels are classified according to increasing proportion of alloying elements and also phase change during heating and cooling as follows:
low alloy steels
medium alloy steels
high alloy steels
and according to the number of alloying elements as follows:
ternary - one element
quarternary - two elements
complex - more than two elements

General description

Low alloy steels

These generally have less than 1.8% nickel, less than 6% chromium, and less than 0.65% molybdenum. The tensile strength range is from 450-620 N mm-’ up to 85O-1000 N mm-2

Medium alloy steels

These have alloying elements ranging from 5-12%. They do not lend themselves to classification. They include: nickel steels used for structural work, axles, shafts, etc.; nickel-molybdenum steels capable of being case-hardened, which are used for cams, camshafts, rolling bearing races, etc.; and nickelchromemolybdenum steels of high strength which have good fatigue resistance.

High alloy steels

These have more than 12% alloying elements. A chromium content of 13-18% (stainless steel) gives good corrosion resistance; high wear resistance is obtained with austenitic steel containing over 11% manganese. Some types have good heat resistance and high strength.

Gas Turbine Cycle

2008-05-27T23:32:00.000-07:00

The gas turbine is used in a wide range of applications. Common uses include power generation plants and military and commercial aircraft. In Jet Engine applications, the power output of the turbine is used to provide thrust for the aircraft.

In a simple gas turbine cycle, low pressure air is drawn into a compressor (state 1) where it is compressed to a higher pressure (state 2). Fuel is added to the compressed air and the mixture is burnt in a combustion chamber. The resulting hot products enter the turbine (state 3) and expand to state 4. Most of the work produced in the turbine is used to run the compressor and the rest is used to run auxiliary equipment and produce power.

Air standard models provide useful quantitative results for gas turbine cycles. In these models the following assumptions hold true.

The working substance is air and treated as an ideal gas throughout the cycle
The combustion process is modeled as a constant pressure heat addition
The exhaust is modeled as a constant pressure heat rejection process

In cold air standard (CAS) models, the specific heat of air is assumed constant at the lowest temperature in the cycle.

Brayton Cycle
The Brayton cycle depicts the air-standard model of a gas turbine power cycle.

The four steps of the cycle are:

(1-2) Isentropic Compression
(2-3) Reversible Constant Pressure Heat Addition
(3-4) Isentropic Expansion
(4-1) Reversible Constant Pressure Heat Rejection

The pv and Ts diagrams are shown below.

Cutting-tool materials

2008-05-27T21:19:00.000-07:00

Carbon steels

Their use is restricted to the cutting of soft metals and wood. Performance is poor above 250°C.

High-speed Steels

These are used extensively, particularly for multi-point tools. They have been replaced to a large extent by carbides for single-point tools. Their main application
is for form tools and complex shapes, e.g. for gearcutting and broaching. They are also used for twist drills, reamers, etc.

Carbides

These consist of powdered carbides of tungsten, titanium, tantalum, niobium, etc., with powdered cobalt as binder. They are produced by pressing the powder
in dies and sintering at high temperature. They are then ground to the final shape. They are generally used as tips and can operate up to 1oo0"C.

Laminated carbide

These consist of a hard thin layer of titanium carbide bonded to a tungsten carbide body. The surface has very high strength at high temperature, whilst the body has high thermal conductivity and thus efficient removal of heat.

Diamonds

These are the hardest of all cutting materials with low thermal expansion and good conductivity. They are twice as good as carbides under compression. A good finish can be obtained with non-ferrous metals and final polishing can be eliminated. Diamonds are particularly good for cutting aluminium and magnesium alloys, copper, brass and zinc. They have a long life.

Pipe Equations

2008-05-26T02:18:00.000-07:00

Pipe cross-sectional area, empty pipe weight, pipe filled with water weight, inside and outside pipe surface area for a unit length pipe can be calculated with the equations below.
pipe diameter cross sectional area
Cross Sectional Area
Cross-sectional Area of a Steel Pipe can be calculated as
A = 0.785 di 2
where
A = cross-sectional area of pipe (Square Inches)
di = inside diameter (inches)

Weight of Empty Steel Pipes
Weight of empty steel pipes can be calculated as
wp = 10.6802 t (do - t)
where
wp =weight of steel pipe (Pounds per Foot Pipe)
t = pipe wall thickness (Inches)
do = outside diameter (inches)

Weight of Water in Pipes filled with Water
Weight of water in pipes filled with water can be calculated as
ww = 0.3405 di 2
where
ww = weight of steel pipe filled with water (Pounds per Foot Pipe)
di = inside diameter (inches)

Outside Surface Area of Pipes
Outside surface area of steel pipes can be calculated as
Ao = 0.2618 do
where
Ao = outside area of pipe - per foot (Square Feet)
do = outside diameter (inches)

Inside Surface Area of Pipes
Inside surface area of steel pipes can be calculated as
Ai = 0.2618 di
where
Ai = inside area of pipe - per foot (Square Feet)
di = inside diameter (inches)

Area of the Metal
Area of the metal can be calculated as
Am = 0.785 (do 2 - di 2)
where
Am = area of the metal (Square inches)
di = inside diameter (inches)
do = outside diameter (inches)

ANSI - American National Standards Institute

2008-05-25T02:01:00.000-07:00

The American National Standards Institute - ANSI - is a private, non-profit organization that administers and coordinates the U.S. voluntary standardization and conformity assessment system.

ANSI provides a forum for development of American national standards from organizations as

and serves as a coordination point for national distribution of international standards issued from organizations as

ISO - International Organization for Standardization,
DIN - Deutsches Institut für Normung eV,
IEC - International Electro technical Commission and others.

Many of committees are chaired and sponsored by engineering societies such as

Safety is the basic objective in the standards developed by ANSI. The ANSI standards include prohibition for practices considered unsafe.

Some of the ANSI codes may eventually become known as ASME standards - as the ANSI B31 Pressure Piping Code is changed to ASME B31.

Gas Welding

2008-05-24T02:45:00.000-07:00

In gas welding the heat to melt the metal parts being welded is produced by the combination of oxygen and an inflammable gas such as acetylene, propane, butane, etc. Acetylene is the most commonly used gas; propane and butane are cheaper but less efficient.

Oxyacetylene welding
A flame temperature of about 3250 "C melts the metals which fuse together to form a strong joint. Extra metal may be supplied from a filler rod and a flux may be used to prevent oxidation. The gas is supplied from high pressure bottles fitted with special regulators which reduce the pressure to 0.134.5 bar. Gauges indicate the pressures before and after the regulators. A torch mixes the gases which issue from a copper nozzle designed to suit the weld size. The process produces harmful radiation and goggles must be worn. The process is suitable for steel plate up to 25mm thick, but is mostly used for plate about 2 mm thick.

Pipe Formulas

2008-05-24T02:29:00.000-07:00

The calculator is based on the piping formulas and equations below:

Moment of Inertia
Moment of inertia can be expressed as
I = 0.0491 (do4 - di4)
where
I = moment of inertia (in4)
do = outside diameter (in)
di = inside diameter (in)

Section Modulus
Section modulus can be expressed as
Z = 0.0982 (do4 - di4) / do
where
Z = section modulus (in3)

Transverse Metal Area
Transverse metal area can be expressed as
Am = π (do2 - di2) / 4
where
Am = transverse metal area (in2)

External Pipe Surface
External pipe or tube surface per ft of length can be expressed as
Ao = π do / 12
where
Ao = external pipe surface area (ft2 per ft pipe)

Internal Pipe Surface
Internal pipe or tube surface per ft of length can be expressed as
Ai = π di / 12
where
Ai = internal pipe surface area (ft2 per ft pipe)

Transverse Internal Area
Transverse internal area can be expressed as
Aa = 0.7854 di2
where
Aa = transverse internal area (in2)

Circumference External
External circumference can be expressed as
Ce = π do
where
Ce = external circumference (in)

Circumference Internal
Internal circumference can be expressed as
Ci = π di
where
Ci = internal circumference (in)

Arc welding

2008-05-23T02:53:00.000-07:00

The heat of fusion is generated by an electric arc struck between two electrodes, one of which is the workpiece and the other a ‘welding rod’. The welding rod is made of a metal similar to the workpiece and is coated with a solid flux which melts and prevents oxidation of the weld. The rod is used to fill the welded joint. Power is obtained from an a.c. or d.c. ‘welding set’ providing a regulated low-voltage high-current supply to an ‘electrode holder’ and ‘earthing clamp’. The work is done on a steel ‘welding table’ to which the work is clamped and to which the earthing clamp is attached to complete the circuit.

Miscellaneous metals

2008-05-22T02:34:00.000-07:00

Antimony
A brittle lustrous white metal used mainly as an alloying element for casting and bearing alloys and in solders.

Beryllium
A white metal similar in appearance to aluminium. Brittle at room temperature. Has many applications in the nuclear field and for electronic tubes. With copper and nickel it produces alloys with high strength and electrical conductivity. Beryllium iron has good corrosion and heat resistance.

Cadmium
A fairly expensive soft white metal like tin. Used for plating and electrical storage batteries. It has good resistance to water and saline atmospheres and is useful as plating for electrical parts since it takes solder readily.

Chromium
A steel-grey soft but brittle metal. Small traces of carbide give it extreme hardness. It is used extensively in alloys and for electroplating and is also used for electrical resistance wire and in magnet alloys.

Lead
A heavy, soft, ductile metal of low strength but with good corrosion resistance. It is used for chemical equipment, roofing, cable sheathing and radiation shielding. It is also used in alloys for solder and bearings.

Lead-tin alloys
These are used as ‘soft solders’, often with a little antimony for strength. Tinman’s solder Approximately 2 parts of tin to 1 part of lead. Used for electrical jointing and tinplate can sealing. Plumber’s solder Approximately 2 parts of lead to 1 part of tin. Used for wiping lead pipe joints. Type metal Contains about 25% tin, with lead and some antimony. Has negligible shrinkage. Bearing metal Lead based ‘white metal’ contains lead, tin, antimony and copper, etc.

Magnesium
A very light metal, only one-quarter the weight of steel and two-thirds that of aluminium, but not easily cold worked. Usually alloyed with up to 10% aluminium and often small amounts of manganese, zinc and zirconium. Used for aircraft and internal combustion engine parts, nuclear fuel cans and sand and die castings. Magnesium and its alloys corrode less in normal temperatures than does steel.

Manganese
A silvery white hard brittle metal present in most steels. It is used in manganese bronze and high nickel alloys and to improve corrosion resistance in magnesium alloys.

Nickel
Nickel has high corrosion resistance. It is used for chemical plant, coating steel plate and electroplating as a base for chromium. Nickel is used for many steel, iron and non-ferrous alloys. Nickel-base alloys Monel Used for steam turbine blades and chemical plant. Composition: 68%Ni, 3o%cu, 2%0Fe. Inconel Good at elevated temperatures, e.g. for cooker heater sheaths. Composition: 8O%Ni, 14%Cr, 6%Fe.
Nimonic A series of alloys based on 70-80%Ni, with small amounts of Ti, Co, Fe, A1 and C. Has high resistance to creep and is used for gas turbine discs and blades, and combustion chambers. Strong up to 900 “C.

Platinum
A soft ductile white metal with exceptional resistance to corrosion and chemical attack. Platinum and its alloys are widely used for electrical contacts, electrodes and resistance wire.

Silver
A ductile malleable metal with exceptional thermal and electrical conductivity. It resists most chemicals but tarnishes in a sulphurous atmosphere. It is used for electrical contacts, plating, bearing linings and as an alloying element.

Tin
A low-melting-point metal with silvery appearance and high corrosion resistance. It is used for tinplate, bearing alloys and solder.

Titanium
An expensive metal with low density, high strength and excellent corrosion resistance. It is used in the aircraft industry, generally alloyed with up to 10% aluminium with some manganese, vanadium and tin. Titanium is very heat resistant.

Tungsten
A heavy refractory steel-grey metal which can only be produced in shapes by powder metallurgy (m.p.3410 “C). It is used as an alloying element in tool and die steels and in tungsten carbide tool tips. It is also used in permanent magnets.

Zinc
Pure zinc has a melting point of only 400 “C so is good for die casting, usually with 1-2%0Cu and 4%A1 to increase strength. Used for carburettors, fuel pumps, door handles, toys, etc., and also for galvanizing sheet steel, nails and wire, and in bronze.

Effect of alloying elements

2008-05-21T02:10:00.000-07:00

Aluminium

This acts as a deoxidizer to increase resistance to oxidation and scaling. It aids nitriding, restricts grain growth, and may reduce strength unless in small quantities. The range used is 0-2%.

Chromium

A range of O M % , improves wear, oxidation, scaling resistance, strength and hardenability. It also increases high-temperature strength, but with some loss of ductility. Chromium combines with carbon to form a wear-resistant microstructure. Above 12% the steel is stainless, up to 30% it is used in martensitic and ferritic stainless steel with nickel.

Cobalt

Cobalt provides air hardening and resistance to scaling. It improves the cutting properties of tool steel with 8-10%. With chromium, cobalt gives certain high alloy steels high-temperature scaling resistance.

Copper

The typical range is 0.24.5%. It has limited application for improving corrosion resistance and yield strength of low alloy steels and promotes a tenacious oxide film.

Lead

Up to 0.25% is used. It increases machineability in plain carbon steels rather than in alloy steels.

Manganese

The range used is 0.3-2%. It reduces sulphur brittleness, is pearlitic up to 2%, and a hardening agent up to 1 Yo. From 1-2% it improves strength and toughness and is non-magnetic above 5%.

Molybdenum

The range used is 0.3-5%. It is a carbide forming element which promotes grain refinement and increases high-temperature strength, creep resistance, and hardenability. Molybdenum reduces temper brittleness in nickel-chromium steels.

Nickel

The range used is 0.3-5%. It improves strength, toughness and hardenability, without affecting ductility. A high proportion of it improves corrosion resistance. For parts subject to fatigue 5% is used, and above 27% the steel is non-magnetic. Nickel romotes an austenitic structure.

Silicon

The usual range is 0.2-3%. It has little effect below 3%. At 3% it improves strength and hardenability but reduces ductility. Silicon acts as a deoxidizer.

Sulphur

Up to 0.5% sulphur forms sulphides which improve machineability but reduces ductility and weldability.

Titanium

This is a strong carbide forming element. In proportions of O.2-O.75% it is used in maraging steels to make them age-hardening and to give high strength. It stabilizes austenitic stainless steel.

Tungsten

This forms hard stable carbides and promotes grain refining with great hardness and toughness at high temperatures. It is a main alloying element in high speed tool steels. It is also used for permanent-magnet steels

This is a carbide forming element and deoxidizer used with nickel and/or chromium to increase strength. It improves hardenability and grain refinement and combines with carbon to form wear-resistant microconstituents. As a deoxidizer it is useful for casting
steels, improving strength and hardness and eliminating blowholes, etc. Vanadium is used in high-speed and pearlitic chromium steels.

Vanadium

Best Efficiency Point - BEP

2008-05-20T18:14:00.000-07:00

A pump does not completely convert the kinetic to pressure energy. Some of the energy is always lost internal and external in the pump.

Internal losses

hydraulic losses - disk friction in the impeller, loss due to rapid change in direction an velocities through the pump
volumetric losses - internal recirculation at wear rings and bushes

External losses

mechanical losses - friction in seals and bearings

pump efficiency bep

The efficiency of the pump at the designed point is normally maximum and is called the

Best Efficiency Point - BEP

It is possible to operate the pump at other points than BEP, but the efficiency of the pump will always be lower than BEP.

Typical properties of alloy steels

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Typical properties of alloy steels

Content	Type	Specification	Tensile strength (Nmm-2)	Fatigue limit (Nmm-2)	Weldability	Corrosion resistance	Machine ability	Formability
Low	1 %Cr, Mo	709M40	1240	540	PH/FHTR	PR	F/HTR	F
Low	1.75%Ni,Cr,Mo	817M40	1550	700	PH/FHTR	PR	P/HTR	F
Low	4.25%Ni,Cr, Mo	835M30	1550	700	PH/FHTR	PR	P/HTR	F
Low	3%Cr, Mo, V	897M39	131(1780)	620	PH/FHTR	PR	P/HTR	F
Low	5%Cr, Mo, V	AISI HI 1	2010(A2630)	850 (A1880)	PH/FHTR	PR	P/HTR	F
Medium	9%Ni, Co	HP9/4/45 Republic Steel	1390 (1850)	-	FHTR	PR	P/HTR	F
Medium	12-14%Cr	410S21	1160	340	P/FHTR	F	F/HTR	F
Medium	Cr, W, Mo. V	Vascojet MA, Vanadium alloy steel	2320 (A3090)	960	PH/FHTR	PR	P/HTR	F
High	13%Cr, Ni, Mo	316S12	620	260	G	G	F	G
High	19%Cr,Ni, Mo	317S16	650	260	G	G	F	G
High	15%Cr, Ni, Mo, V	ESSHETE 1250 S. Fox	590	-	G/FHTR	G/HT	F	-
High	17%Cr,Ni	AISI 301	740(CR1240)	280	F	F	F	G
High	17% Cr, Ni, AI	1717 PH Armco	1480	-	F	F	F	G
High	14%Cr, Ni, Cu. Mo, Nh	REX 627 Firth Vickers	1470	540	FHTR	F	F	F
High	15%Cr, Ni, Mo, V	AM 355 Allegheny Ludlum	1480	740	FHTR	F	F	F
High	18%Ni, Co, Mo	300grade maraging INCO	1930	-	G/FHTR	PR	F	P
High	18%Ni, Co, Mo	250grade maraging	1700	660	G/FHTR	PR	F	P

A = ausformed, MA = martempered, CR =cold rolled, P = poor, F = fair, G = good, PH = preheat required, PR = protection required, HT = at high temperature, HTR = when heat treated, FHTR=final heat treatment required.

DIN - Deutsches Institut für Normung

2008-05-19T02:59:00.000-07:00

DIN - Deutsches Institut für Normung, the German Institute for Standardization, is a non-governmental organization recognized by the German government as the national standards body and represents German interests at international and European level.

DIN Standards promote rationalization, quality assurance, safety, and environmental protection as well as improving communication between industry, technology, science, government and the public domain. Standards work is carried out by 26,000 external experts serving as voluntary delegates in more than 4,000 committees. Draft standards are published for public comment, and all comments are reviewed before final publication of the standard. Published standards are reviewed for continuing relevance every five years, at least.

The over 12,000 DIN standards cover a wide range of topics including: physical quantities and units, fasteners, water analysis, building and civil engineering (including building materials, construction contract procedures (VOB), soil testing, corrosion protection of steel structures), materials testing (testing machines, plastics, rubber, petroleum products, semiconductors), steel pipes, machine tools, twist drills, roller and ball bearings, and process engineering. DIN Handbooks (covering subjects such as mechanical engineering, fasteners, steel, steel pipes, and welding), and most DIN standards are available as English versions, or as English translations.

DIN standards designation
The designation of a DIN standard shows its origin (# denotes a number):
* DIN # is used for German standards with primarily domestic significance or designed as a first step toward international status
* E DIN # is a draft standard and
* DIN V # is a preliminary standard
* DIN EN # is used for German edition of European standards
* DIN ETS # is used for standards prepared by European Telecommunications Standards Institute
* DIN ISO # is used for German edition of ISO standards
* DIN EN ISO # is used if the standard as also been adopted as a European standard

Examples - DIN Standards
* DIN 75078-1 Motor vehicle for the transport of persons with reduced mobility - Part 1: Terms and definitions, requirements, tests
* DIN V 4108-4 Thermal insulation and energy economy in buildings - Part 4: Hygrothermal design values
* DIN EN 126 Multifunctional controls for gas burning appliances
* DIN EN ISO 10042 Welding - Arc-welded joints in aluminum and its weldable alloys - Quality levels for imperfections (ISO/DIS 10042:2004)

Temperature

2008-05-19T01:02:00.000-07:00

Temperature (sometimes called thermodynamic temperature) is a measure of the average kinetic energy of a systems particles. Temperature is the degree of "hotness" ( or "coldness"), a measure of the heat intensity.

When two objects of different temperature are in contact, the warmer object becomes colder while the colder object becomes warmer. It means that heat flows from the warmer object to the colder one.

Degree Celsius (oC) and Degree Fahrenheit (oF)
Thermometer helps us determine how cold or how hot a substance is. Temperatures in science (and in most of the world) are measured and reported in degrees Celsius (oC). In the US, it is common to report temperature in degrees Fahrenheit (oF). On both the Celsius and Fahrenheit scales the temperature at which ice melts (water freezes) and the temperature at which water boils, are used as reference points.

On the Celsius scale, the freezing point of water is defined as 0 oC, and the boiling point of water is defined as 100 oC.
On the Fahrenheit scale, the water freezes at 32 oF and the water boils at 212 oF.

On the Celsius scale there are 100 degrees between freezing point and boiling point of water, compared to 180 degrees on the Fahrenheit scale. This means that 1 oC = 1.8 oF.
Thus the following formulas can be used to convert temperature between the two scales:
tF = 1.8 tC + 32 = 9/5 tC + 32 (1)
tC = 0.56(tF -32) =5/9(tF - 32) (2)
where
tC = temperature in oC
tF = temperature in o
Example - A patient with SARS (Severe Acute Respiratory Syndrome) has a temperature of 106 oF. What does this read on a Celsius thermometer?
tC = 5/9 (106-32)= 41.1 oC

Degree Kelvin - K
Another scale (common in science) is Kelvin, or the Absolute Temperature Scale. On the Kelvin scale the coldest temperature possible, -273 oC, has a value of 0 Kelvin (0 K) and is called the absolute zero. Units on the Kelvin scale are called Kelvins (K) and no degree symbol is used.
Because there are no lower temperatures the Kelvin scale do not have negative numbers.

A Kelvin equal in size to a Celsius unit: 1 K= 1 oC.
To calculate a Kelvin temperature, add 273 to the Celsius temperature:
tK = tC + 273.16 (3)

Example - What is normal body temperature of 37 oC on the Kelvin scale?
tK = tC + 273.16 = 37 + 273.16 = 310.16 K

Degree Rankine - R
In the English system the absolute temperature is in degrees Rankine (R), not in Fahrenheit:
tR = tF + 459.69 (4)

Density, Specific Weight and Specific Gravity

2008-05-19T00:56:00.000-07:00

Density
Density is defined as an objects mass per unit volume. Mass is a property.

Mass and Weight - the Difference! - What is weight and what is mass? An explanation of the difference between weight and mass.

The density can be expressed as
ρ = m / V = 1 / vg (1)
where
ρ = density (kg/m3)
m = mass (kg)
V = volume (m3)
vg = specific volume (m3/kg)

The SI units for density are kg/m3. The imperial (BG) units are lb/ft3 (slugs/ft3). While people often use pounds per cubic foot as a measure of density in the U.S., pounds are really a measure of force, not mass. Slugs are the correct measure of mass. You can multiply slugs by 32.2 for a rough value in pounds.

Unit converter for other units

The higher the density, the tighter the particles are packed inside the substance. Density is a physical
property constant at a given temperature and density can help to identify a substance.

Densities and material properties for common materials

Relative Density
Relative density of a substance is the ratio of the substance to the density of water, i.e.

Example - Use the Density to Identify the Material:
An unknown liquid substance has a mass of 18.5 g and occupies a volume of 23.4 ml. (milliliter).

The density can be calculated as
ρ = [18.5 (g) / 1000 (g/kg)] / [23.4 (ml) / 1000 (ml/l) 1000 (l/m3) ]
= 18.5 10-3 (kg) / 23.4 10-6 (m3)
= 790 kg/m3

If we look up densities of some common substances, we can find that ethyl alcohol, or ethanol, has a density of 790 kg/m3. Our unknown liquid may likely be ethyl alcohol!

Example - Use Density to Calculate the Mass of a Volume
The density of titanium is 4507 kg/m3 . Calculate the mass of 0.17 m3 titanium!
m = 0.17 (m3) 4507 (kg/m3)
= 766.2 kg

Specific Weight
Specific Weight is defined as weight per unit volume. Weight is a force.
* Mass and Weight - the difference! - What is weight and what is mass? An explanation of the difference between weight and mass.
Specific Weight can be expressed as

γ = ρ g (2)
where
γ = specific weight (N/m3)
ρ = density (kg/m3)
g = acceleration of gravity (m/s2)

The SI-units of specific weight are N/m3. The imperial units are lb/ft3. The local acceleration g is under normal conditions 9.807 m/s2 in SI-units and 32.174 ft/s2 in imperial units.

Example - Specific Weight Water
Specific weight for water at 39 oF (4 oC) is 62.4 lb/ft3 (9.81 kN/m3) in imperial units. Specific weight in SI units can be calculates like
γ = 1000 kg/m3 9.81 m/s2
= 9810 N/m3
= 9.81 kN/m3

Apdicatioas of copper and copper alloys

2008-05-16T01:59:00.000-07:00

Type and composition	Condition	Tensile MN/m2	Product	Use
Pure copper 99.95%Cu	O	220	Sheet, strip wire	High conductivity electrical applications
	H	350
98.85%cu	O	220	All wrought forms	Chemical plant. Deep drawn, spun articles
	H	360
99.25%cu +0.5%As	O	220	All wrought forms	Retains strength at high temperatures. Heat exchangers, steam pipes
	H	360
Brasses 9O%Cu, 10%Zn-gilding metal	O	280	Sheet, strip and wire	Imitation jewellery, decorative work
	H	510
7o%cU, 30%Zn-Cartridge brass	O	325	Sheet, strip	High ductility for deep drawing
	H	700
65%Cu, 35%Zn- standard brass	O	340	Sheet, strip and extrusions	General cold working alloy
	H	700
60%Cu, 40%Zn- Muntz metal	M	375	Hot rolled plate and extrusions	Condenser and heat exchanger plates
59%Cu, 35%Zn, 2%Mn, 2%A1, 2%Fe	M	600	Cast and hot worked forms	Ships screws, rudders
58%Cu, 39%Zn, 3%Pb free cutting	M	440	Extrusions	High speed machine parts
Bronzes 95.5%Cu, 3%Sn, 1.5Zn	O	325	Strip	Coinage
	H	725
5.5%Sn, O.l%Zn, Cu	O	360	Sheet, strip and wire	Springs, steam turbine blades
	H	700
10%Sn, 0.03-0.25P, Cu- phosphor bronze	M	280	Castings	Bushes, bearings and springs
10%Sn, O.S%P, Cu	M	280	Castings	General-purpose castings and bearings
10%Sn, 2%Zn, Cu-Admiralty gunmetal	M	300	Castings	Pressure-tight castings, pump,valve bodies
Aluminium bronze 95?'ocU, 5%AI	O	400	Strip and tubing	Imitation jewellery, condenser tubes
	H	770
10Y0A1, 2.5%Fe, 2-5%Ni, Cu	M	700	Hot worked and cast products	High-strength castings and forgings
Cupronickel 75%cu, 25%Ni	O	360	Strip	British 'silver' coinage
	H	600
70%Cu, 30%Ni	O	375	Sheet and tubing	Condenser tubes, good corrosion resistance
	H	650
29%cu, 68%Ni, 1.25%Fe,1.25%Mn	O	550	All forms	Chemical plant, good corrosion resistance
	H	725
Nickel-silver 55%Cu, 27%Zn, l8%Ni	O	375	Sheet and strip	Decorative use and cutlery
	H	650
Ber y llium-copper 1.75-2.5%Be, 0.5% co, c u	WP	1300	Sheet, strip, wire, forgings	Non-spark tools, springs

0 =annealed, M =as manufactured, H =fully work hardened, WP=solution heat treated and precipitation hardened.

British Standard specification of steels

2008-05-16T01:08:00.000-07:00

The relevant standard is BS 970 ‘Wrought Steels’. The standard is in six parts:
Part 1 Carbon and carbon manganese steels including free-cutting steels
Part 2 Direct hardening alloy steels
Part 3 Steels for Case Hardening
Part 4 Stainless, heat resisting and spring steels
Part 5 Carbon and alloy spring steels
Part 6 SI metric values (for use with Parts 1 to 5)

Each steel is designated by six symbols:
First three digits
000-199: Carbon and carbon-manganese steels. Digits represent 100 times the percentage of manganese.
200-240: Free cutting steels. Second and third digits represent 100 times the percentage of sulphur.
250: Silicon-manganese steel
300-449 : Heat-resistant, stainless and valve steels
500-999: Alloy steels
Letter
The letters A, M, H and S indicate if the steel is supplied to - chemical analysis, mechanical properties, hardenability requirements, or is stainless, respectively.
Last two digits
These give 100 times the percentage of carbon, except for stainless steels.
Example
070M20: A plain carbon steel with 0.2% carbon and 0.7% manganese. The mechanical properties, i.e. tensile strength, yield strength, elongation and hardness, are given in the standard.

Elastohydrodynamic (EHD) Lubrication

2008-05-09T19:24:00.000-07:00

Definition of EHD lubrication.
The lubrication principles applied to rolling bodies, such as ball or roller bearings, is known as elastohydrodynamic (EHD) lubrication.

Rolling body lubrication.
Although lubrication of rolling objects operates on a considerably different principle than sliding objects, the principles of hydrodynamic lubrication can be applied, within limits, to explain lubrication of rolling elements. An oil wedge, similar to that which occurs in hydrodynamic lubrication, exists at the lower leading edge of the bearing. Adhesion of oil to the sliding element and the supporting surface increases pressure and creates a film between the two bodies. Because the area of contact is extremely small in a roller and ball bearing, the force per unit area, or load pressure, is extremely high. Roller bearing load pressures may reach 34,450 kPa (5000 lb/sq in) and ball bearing load pressures may reach 689,000 kPa (1,000,000 lb/sq in). Under these pressures, it would appear that the oil would be entirely squeezed from between the wearing surfaces. However, viscosity increases that occur under extremely high pressure prevent the oil from being entirely squeezed out. Consequently, a thin film of oil is maintained.

Effect of film thickness and roughness.

The roughness of the wearing surfaces is an important consideration in EHD lubrication. Roughness is defined as the arithmetic average of the distance between the high and low points of a surface, and is sometimes called the centerline average (CLA).
As film thickness increases in relation to roughness fewer asperities make contact. Engineers use the ratio of film thickness to surface roughness to estimate the life expectancy of a bearing system. The relation of bearing life to this ratio is very complex and not always predictable. In general, life expectancy is extended as the ratio increases. Full film thickness is considered to exist when the value of this ratio is between 2 and 4. When this condition prevails, fatigue failure is due entirely to subsurface stress. However, in most industrial applications, a ratio between 1 and 2 is achieved. At these values surface stresses occur, and asperities undergo stress and contribute to fatigue as a major source of failure in antifriction bearings

search report

2008-04-20T18:04:00.000-07:00

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2008-04-18T21:45:00.000-07:00

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