Compressed Air Glossary: T to Z

Two Stage Compressors: A compressor having two chambers & one air discharge.

Temperature, Discharge: The total temperature at the discharge flange of the com­pressor.

Thermal Compressor: An ejector used to compressor waste or any gas through moderate compression above atmospheric pressure.

Tilting Pad: A type of journal bearing in centrifugal air compressors.

Theoretical Power: The power required to compress a gas isothermally through a specified range of pressures.

Trunk Compressor: A compressor belonging to the group of displacement reciprocating compressors.

Trunnion: A cylindrical projection used as a mounting and/or pivoting point.

Tugger: A device which is operated by air to pull or tug in an effort to move something.

Two Step Control: Load/unload control system which helps maximize the efficiency of compressor by matching air delivery & air demand.

TXV Valve: Thermal Expansion valve.

Ultrasonic Leak Detector: An instrument which helps to detect ultrasonic emissions & alter them to audible signal.

UNC: Unified National Coarse. It is a thread form with rounded roots & flat crests with 60 degree flank angle. As for a given diameter it has larger thread pitch.

UNF: Unified National Fine. It is a thread form with rounded roots & flat crests with 60 degree flank angle. As for a given diameter it has smaller thread pitch.

Unit Type Compressor: A machine in which compressors of 20 HP or less are combined with all the required components to start the operation.

Unloaded Horsepower: The power consumed to overcome the frictional losses while operating in an unloaded condition.

Vacuum Pumps: Compressors that operates by in taking atmospheric pressure & discharging atmospheric pressure or slightly higher.

Valves: A device with passages that helps directing the flow of air into alternate paths.

Vane Compressors: A single shaft positive displacement rotary compressor.

Vapor Pressure: The pressure exerted by the vapour bounded within the given space. The vapour can be a sole occupant or associated with other gases in the space.

V Belt Drive: A drive that transfers power to compressors.

Volute: A spiral shaped stationary passage that converts velocity head to pressure.

Voting Alarm: A 3 sensors alarm system that is connected to compressors or turbines & requires at least 3 alarms before the alarms act.

Water-cooled Compressor: Compressors that are cooled by water circulating jackets surrounding the cylinders or casings.

Whipcheck: Safety cables that help restrain air hoses if any end breaks.

Working Pressure: A normal working pressure required to operate an air motor.

Xenon: An inert gaseous element.

Yoke: A portion of safety valve that surrounds the spring.

Zero: The temperature of pure melting ice under standard atmospheric pressure on the Centigrade & Réaumur scales.

Compressed Air Glossary: M to S

Multicasing Compressor: When two or more compressors, each with a separate casing, are driven by a single motor or turbine, the combined unit is called a multicasing compressor.

Multistage Axial Compressor: A machine having two or more rows of muting vanes operating in series on a single rotor and in a single casing.

Multistage Compressors: Machines employing two or more stages.

Modulating Control: Compressor controls will run the compressor at varying loads to accommodate demand variations.

Off-Load: The compressor which is running & consuming power but is not delivering air.

On-Load: The compressor producing air, either at part load or full load.

Oil-free air: Compressed air produced by a compressor with no oil present in the compression cycle.

Oil Separator: A device that separates oil from the condensate.

OSHA Valve: Valve used to depressurize a system when pressure drop is noticed.

Packaged Air System: Self contained unit consisting of a compressor, a prime mover & various accessories.

Pascal (Pa): The SI derived unit of pressure.

Pressure Drop: A term used to describe the decrease in pressure from one point in a pipe or tube to another.

Pressure Regulator: A device used to decrease the incoming pressure to a lower level & maintains it irrespective to the changes in inlet pressure & outlet flow rate.

Prime Motor: A machine used to derive a compressor.

Particulates: Solid materials such as dust, rust, pollen, etc that is present in air stream.

PPM: Parts Per Million, measurement of the oil present in compressed air.

Receivers: Tanks used to store compressed air & help damp discharge line pulsations.

Reciprocating Compressor: It is a positive displacement compressor which is driven by a piston having a reciprocating motion in a cylinder.

Reduced Pressure: Ratio of actual pressure of a gas to its critical pressure.

Reheaters: Heat exchanger for increasing the temperature of compressed air to increase its volume.

Rotor: A rotating element in a machine & is composed of impeller & shaft.

Rotary Compressor: An air compressor using a rotary impeller driving air through a curved chamber to compress the air.

Regulator: An automatic or manual device designed to control pressure, flow or temperature.

Relief valve: A type of valve used to control or limit the pressure in a system or vessel which can build up by a process upset, instrument or equipment failure.

Refrigeration Dryer: A device consisting of a heat transfer system, a moisture elimination system and a refrigeration system designed to improve the quality of the air and reduce the temperature of the air.

Safety Valve: A device that limits liquids & gas pressure by discharging some of the pressurized liquid or gas.

Safety Relief Valve: An automatic pressure relieving device actuated by the static pressure upstream of the device, which opens in proportion to the increase in pressure over the opening pressure.

Standard Air: Air at a temperature of 68 °F, a pressure of 14.70 psia and a relative humidity of 36 per cent (0.0750 density) (as per A.S.M.E. however in the gas industry the temperature of standard air is usually given as 60 °F.

SCFM: Standard cubic feet per minute.

Set Pressure: The gauge pressure at which a safety valve visibly and audibly opens or at setting which a relief valve discharges an unbroken stream of liquid.

Shaft: A rotating element part on which a rotating division is mounted & therefore helps transmits energy from the prime mover.

Surge Limit: It is the capacity below which the compressor operation becomes unstable.

Compressed Air Glossary: E to L

Efficiency Compression: The ratio of the theoretical work requirement to the actual work required to be performed on the gas within the cylinder.

Expanders: Engines or turbines in which gas expands, does work & undergoes a drop in temperature.

Filters: Devices that removes or separate the unwanted liquid & dust from air before it enters the compressor.

Fluidics: The general subject of instruments and controls dependent upon low rate flow of air or gas at low pressure as the operating medium.

Gas Bearings: These are load carrying machine which allows some movement in which the lubricant is air or some other gas.

Guide Vane: An adjustable stationary element that helps direct the flowing medium to the inlet of an impeller.

Gauge Pressure: Pressure determined by instruments or gauges.

Head, Adiabatic: The energy in foot pounds required to compress adiabatically and to deliver one pound of a given gas from one pressure level to another.

High Pressure air: Air which is compressed above 150 PSI.

Humidity Relative: The ratio of the partial pressure of the vapour to the vapour saturation pressure at the dry bulb temperature of the mixture.

Inlet Pressure: The pressure at the inlet flange of the compressor, measured in PSIG.

Intercooling: The removal of heat from gas or air between compressor stages.

Inducer: A curved inlet section on impeller.

Intercoolers: heat exchanger device which removes the heat of compression between the stages of compressor.

kPa: Equal to 1000 Pa.

Liquid Piston: A liquid piston compressor is a rotary compressor in which a vaned rotor revolves in an elliptical casing, with the rotor spaces sealed by a ring of liquid rotating with it inside the casing.

Load Time: Time period from when a compressor loads until it unloads.

Load/Unload Control: Control method that allows the compressor to run at full-load or at no load while the driver remains at a constant speed.

Compressed Air Glossary: A to D

Precise information on compressed air system terms is always valuable. Glossary of terms for people who work with compressed air solution.

Absolute Pressure: The total pressure measured from absolute zero.

Ambient Air: Air or Temperature surrounding you.

Absolute Temperature: Temperature calculated from absolute zero on the Kelvin scale or on Rankine scale.

Absolute Zero: Temperature at lowest possible point. The temperature at which kinetic energy is of atoms & molecule are at minimal.

Aftercooler: The heat exchanger unit which helps cooling the air or gas discharged from compressor before it enters the system.

Actual Capacity: Quantity of gas actually compressed & delivered to the discharge system at given rated speed of machine & under given pressure conditions.

Adiabatic Compression: A type of compression where no heat is transferred to or from the gas during the compression process.

Air cooled compressor: Compressors are cooled by atmospheric air by circulating them around the cylinders or casings.

Air Receivers: A vessel designed to store the compressed air & to permit pressure to be stable in the system.

Air Dryer: Devices which will help absorb water vapour from compressed air.

Automatic Sequencer: A device which operates compressors in sequence according to a programme schedule.

Atmospheric Pressure: The pressure exerted by the atmosphere.

Bar: A unit of pressure used in industry field, which is approximately equal to atmospheric pressure.

Base Plate: A metallic structure on which a compressor or other machine is mounted.

Booster Compressor: A machine which helps compressing air or gas from an initial pressure to much higher pressure.

Boss hose fitting: Threaded fitting which connects hose from compressor or extended hose for flow of gas.

Capacity: The amount of air flow delivered from compressor under specific conditions & is usually expressed in cubic feet per minute (CFM).

Casing: The pressure containing stationary element that encloses the rotor & associated internal components of the compressors, and it includes integral inlet and discharge corrections.

Check Valve: A mechanical device which allows the flow of liquid or gas in one direction.

Condensate: Liquid formed in compressor from water vapour due to decrease in temperature &/or increase in pressure.

CFM: Volumetric air flow rate.

Compression Ratio: The ratio of the discharged pressure to the inlet pressure.

Constant Speed Control: A system which runs continuously & matches air supply to demand, by varying compressor load.

Cycle: The series of steps that a compressor performs.

Cut In/Out Pressure: A setting on a pressure discharge used to either load or unload the compressor on a content speed application to either start or stop the machine.

Compressibility: A factor expressing the deviation of gas from the laws of hydraulics.

Compression, Adiabatic: A compression where no heat is transferred to or from the gas during the compression process.

Compression, Isothermal: A compression in which the temperature remains constant. For reversible process the equation PV is constant for perfect gases.

Compression, Polytropic: A graphical relationship between the pressure & volume for various values of specific-heat ratio in a compressor equation pVⁿ = K.

Compression Ratio: The ratio of the discharged pressure to the inlet pressure.

Critical Pressure: It is the saturation pressure at the critical temperature.

Critical Temperature: The highest temperature at which well defined vapor & liquid state exist.

Dew Point: The temperature at which the air gets saturated & changes from vapour to liquid at a given pressure.

Dew Point Suppression: Temperature below ambient.

Desiccant: An adsorption type material which attracts & remove water vapour from the air.

Discharge Pressure: It is the pressure generated on the output side of a gas compressor.

Discharge Temperature: The temperature existing at the discharged port of the compressor.

Dynamic-type Compressors: Air or gas compressed by rotating vanes or impellers.

Industrial Air Compressor

Industries have always opted for better & fast machinery to eliminate energy wastage & minimize time consumption. Industrial Air Compressors have become a must tool for all industry & manufacturers. These industrial air compressors are used to power many types of tool to yield better & fast result.

Industrial air compressors models are different, more powerful & more expensive than the ones that are used in small jobs or at home. These types of machinery are designed to yield more power source particularly for an industrial use. Natural gas or electricity is used as a fuel for industrial air compressors. Though both these types of fuel are used to run the industrial air compressors, many businesses opt for using natural gas as a power source as it significantly help reduce their utility cost.

There are 3 types of Industrial air compressors, reciprocating, rotary & centrifugal. Industrial air compressor differs from other compressors for its size, power & life. Most industries use two-stage model of industrial air compressors as they offer high level of air compression & have ability to store unused air for future use.

These industrial air compressors are more energy efficient machinery because they are running on high level horsepower. This increased usage of horse power tends to make it a better working machine reducing its maintenance and possibility of beak down.

While purchasing a compressor, you should first decide the purpose for buying these machines. Its safety & quality standards should also be considered. All manufacturers are required to buy compressors & there parts by the American Society of Mechanical Engineers (ASME) certified dealer or company.

For safety measure many manufacturers have installed a safety valve which allows the air to be released automatically thereby decreasing the pressure in-case there is a overloading of power.

Industrial air compressors are the King of compressor world. They have much power & can be used for array of tasks.

Werther provides detailed information about, portable & industrial air compressors.

Air Treatment: Compressed Air Filters

Compressed air filters are widely used in industry sphere & are also referred as line filters. These air filters are used to eradicate air, oil, water & other contaminates from compressed air after compression has taken place.

Unwanted particles traveling through compressed air stream can be removed in different ways. A pneumatically operated machine suffers major damage due to unwanted dirt particles, water, oil or moisture. These contamination's’ of the air stream can cause severe performance abjection & increase the maintenance cost. To cut down the costs & damages compressed air filters are used to increase the productivity & performance.

There are different types of Air filters. These filters are designed in a way to remove all contaminations from air supply. 3 Micron per filters are exclusively used to remove solid particles. 1 & 0.01 Micron coalescing filters is used as oil separators. Activated carbon filters are used to eliminate oil vapors & odors. These filters are used in combination with other instruments.

Filtering process always results in a pressure drop & energy is lost in air system. Finer filters also cause greater pressure drop & gets blocked quickly. Because of these results filters need to be changed frequently resulting in higher costs. Accordingly, filters must be shaped in such a way that they are able to handle the normal flow & have a greater capacity to manage pressure drop due to a degree of blockage.

Browse our collection of Air filters.