compressed air compressor Tel: 01480 217904
Fax: 01480 217409

Unit 2 Steel Close
St Neots, PE19 8TT

Glossary of compressed air terms

Activated carbon filtration – Used to remove oil mist, odour and other contaminates from a compressed air line. Often required for breathing air and medical applications.

Absorption dryer – A dryer that uses a desiccant material to remove the moisture from air.

Air receiver – A container used to store compressed air.

Air leak – a place within a system where compressed air is escaping to atmosphere, usually with an annoying hissing sound.

Atmospheric pressure – The measured ambient pressure at a specific location

Automatic drain – An electric operated drain which will open either when it senses moisture, as with a zero-loss drain. Or at set intervals such as 5 seconds every 30 minutes as with a timed drain. These are used at the bottom of receivers to remove build ups of moisture and contaminates.

Bottle neck – A restriction within a compressed air line. For example a 1” header line with a half inch ball valve.

Capacity – The amount of air delivered by a compressor or processed by a method of filtration. Usually measured in cubic feet per minute or litres per second/hour.

Check valve – A non-return valve to stop fluids returning up a line.

Condensate – Contaminates within a volume of compressed air.

Cubic feet per minute – Also known as cfm or scfm (standard cfm), a measurement of the flow of compressed air.

Desiccant – A material used to dry compressed air.

Desiccant dryer – A dryer that uses desiccant to remove the moisture content of compressed air.

Dew point – The temperature at which moisture in the air will begin to condense. At this point the relative humidity is 100%. Dew point is often used in pneumatics to represent the amount of moisture in a compressed air system.

Dew point meter – Used when conducting breathing air tests to give an indication of the moisture content in a compressed air line.

Displacement – The volume of air swept out by the piston or rotor internally inside a compressor. This is actually different from the amount of air available at the outlet of the compressor and some manufacturers use piston displacement figures to show inflated capacity figures for their equipment. Always check the FAD (free air delivered) figure.

Emulsification – when oil or lubricating fluid mixes with moisture it gets jiggy and turns into a mayonnaise like gloop. If this happens inside your compressor, which it often can when the compressor is not being run very much, it can cause further mechanical problems.

Filters- Available in various grades. Line filters are used after the compressor to remove contaminates from the compressed air. Air filters and oil filters are used to protect the mechanical insides of a compressor.

Filter element – the internal cartridge inside a line filter. These get blocked and require changing during routine maintenance.

Filter housing – the casing of a line filter.

Full-load – When a compressor is running at full speed and producing its maximum capacity of air.

Gauge – A small round device that gives a pressure reading. Obviously there are different gauges but these are the most familiar to compressor engineers.

Horsepower – is an electrical measurement used to show the size of a motor.

Intake regulator – regulates the air flow into the compression stage of a compressor.

Intercooling – is the process of removing heat from the compressed air after compression.

Load factor – ratio of average compressor load to the maximum rated compressor load over a certain time period.

MPV minimum pressure valve – allows pressure to build up within a compressor to a certain point where the pressure is great enough to push lubricating fluid around a compressor.

Oil / Air separator – internal component within a compressor that requires changing with routine maintenance. It removes oil from the compressed air prior to discharge.

Oil / Water separator – removes oil and other nasties from the condensate allowing for the remainder fluid to be safely disposed of down drains.

Pressure – force per unit area, measured in psi (pounds per square inch) or bar.

Piston compressor – A compressor that uses a piston to push and compress air.

PSI – Pounds per square inch a measurement of pressure.

Pressure dewpoint – The temperature at which moisture will start to condense back to liquid form. See dewpoint

Pressure drop – The loss of pressure from two given points within a compressed air system. This is caused by friction or a restriction (bottle neck) in the line.

Rotary screw compressor – a rotary compressor that uses two screw elements winding in different directions to create compressed air. Normally more efficient than piston or vane compressors.

Refrigeration dryers - removes moisture from a comrpessed air line via cooling.

Safety valve aka safety relief valve - Releases air at a certain pressure, useful to stop receivers exploding.

Silencer – A muting device used to remove the hissing sound of compressed air being released to atmosphere.

Solenoid valve – Turns an electrical signal into a mechanical valve. We supply valves as normally open or normally closed in either 24V DC 110VAC or 240VAC.

Sequencer – An electronic or mechanic device used to control the sequence in which compressors start up. These are often designed to spread the run hours evenly across multiple compressors within a system.

Unloader – removes built up pressure from within the compressor once the compressor cuts out. This means it can cut in again without trying to start up against built up pressure.

Vacuum pumps – Basically a backwards compressor that sucks air in and creates a vacuum. Application include removing sawdust or paint fumes away from the workshop area.

Valve – Is a mechanical device used to stop or allow air to pass. Various types such as ball valve, solenoid valves, butterfly valves, non return valves etc.

Venturi – A mechanical device that uses compressed air to create a vacuum. Often used with suction pads and pressure pads to automate movement of objects. We have used venturis mounted on mobile receivers as suction vessels to suck in and hold fluids such oil and fuels.

Voltage – A measurement of ‘electrical pressure’. Workshop and DIY compressor are usually 240V where as industrial units run on three phase 400V electrics.

Working pressure – the pressure at which a system generally operates.
Company Reg. 03965250

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