Compressed Air Dictionary

 

Absolute Pressure (PSIA)	At sea level the atmospheric pressure is 14.7 PSI (Pounds per Square Inch). To determine the Absolute Pressure (PSIA) use Gauge Pressure (PSIG) + 14.7 pounds.
Aftercooler	Compressed air must be cooled as it leaves the pump and before it enters the receiver. Heat from the compressed air is transferred outward to the aluminum fins of the aftercooler (the flywheel or fan creates an air flow that rushes past and cools the aluminum fins).
Air Receiver	The air receiver is another name for the air storage tank.
ASME Code	The American Society of Mechanical Engineers (ASME) has certain standards for industry. ASME standards are used to test and certify most mechanical items (such as compressors) sold and serviced by P-M-E Equip.
Burst Pressure	The pressure point at which the pressurized air will cause the vessel or component to fail (or burst).
Bypass	Diverts the pump's compressed air into the atmosphere or around a system component such as a dryer or filter for maintenance.
CFM	Cubic Feet Per Minute is the unit in which air flow is measured.
Check Valve	A valve that allows air to flow in one direction as it prevents air from flowing in the opposite direction.
Continuous Pump CFM	The continuous CFM rating at 90 PSI (Pounds per Square Inch).
Cut In PSI	Air receiver PSI at which the pump starts or the valves "load" and compression begins.
Cut Out PSI	Air receiver PSI at which the pump stops or the valves "unload" and compression stops.
Filter	A device that removes particulate, oil vapor, taste or odor from the air before they reach the pneumatic operated devices.
Gauge Pressure (PSIG)	Pounds per Square Inch as measured by a pressure gauge.
Intercooler	The intercooler cools the compressed air as it travels from one stage to the next higher stage. The flywheel or fan creates an air flow that rushes past and cools the intercooler.
Lubricator	A lubricator allows the internal moving parts of pneumatic equipment to move smoothly and freely.
Pressure Switch	Controls the engine/motor with preset cut-in/cut-out pressure points. Most P-M-E supplied compressors have a more sophisticated pressure switch that helps protect the power source.
Reciprocating Compressor	Reciprocating compressors have an automotive style piston with a connecting rod and a crankshaft.
Recovery Time	The time from cut-in to cut-out where the compressor goes into "no-load" condition.
Regulator	Allows adjustment of the outlet pressure from the receiver.
Rotary Screw Type Compressor	A style of compressor that has two intermeshing helical rotors inside a housing with the air intake on one end and air discharge at the other.
Rotary Sliding Vane Compressor	On the intake cycle, the rotor turns and air is trapped in pockets formed by the vanes of the rotor. During the compression cycle, air is gradually compressed as pockets get smaller. As it is discharged, compressed air is pushed out through the discharge port.
Safety Relief Valve	A valve that opens only when the pressure is greater than the valve safety rating. Relief valves are on the air receiver, the intercooler and often on the aftercooler and should be tested weekly.
SCFM	The Standard Cubic Feet per Minute (SCFM) is a volume of air that has these properties: 68o F. Temperature, 14.7 PSIA Pressure and 36% Relative Humidity.
Stages	Dividing the total pressure among several cylinders thus feeding the exhaust from the first cylinder (low pressure) to the inlet of the next cylinder (high pressure). Cylinder diameters decrease from one stage to the next higher-pressure stage in multistage compressors.
Tank Assisted CFM	The tank assisted CFM (Cubic Feet per Minute) rating is the continuous CFM rating of the pump at 90 PSI plus the tank's stored CFM for one minute at 90 PSI. Use tank assisted CFM rating when sizing the compressor for a large tool that will be operated for less than one minute between recovery times. Use the continuous pump CFM when operating many smaller tools at once for more than one minute.
Unloader	As the compressor cuts-out, the unloader relieves pressure from the discharge line. This assures that the compressor will not be loaded when the motor/engine restarts.
Water Drain	Drains moisture from the air receiver, dryer, or low points in the piping system. To reduce corrosion, the water drains should be opened after each use.
Working Pressure	The maximum safe operating pressure.
Volumetric Efficiency	The actual volume capacity compared to the piston displacement. The efficiency of a pump drops as the pressure goes up.

 

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