Confused by all the acronyms and industry lingo? Look
up the meaning in our convenient compressed air dictionary
of terms and definitions.
| 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. |
