Absorption The chemical process by which a hygroscopic
desiccant, having a high affinity with water, melts and becomes
a liquid by absorbing the condensed moisture.
Actual Capacity Quantity of air or gas actually
compressed and delivered to the discharge system at rated speed
and under rated conditions.
Aeon 9000SP Synthetic compressor lubricant used
mainly in Gardner Denver rotary screw compressors.
Aftercooler A heat exchanger used for cooling
air discharged from a compressor. Resulting condensate may be
removed by a moisture separator following the aftercooler.
Air Compressor Automatic Drain Valve Require no
operator attention and automatically purge water, oil, dust,
rust, metals and other debris to increase performance and decrease
downtime.
Air Compressor Bypass Diverting the pump’s compressed
air to atmosphere.
Air Compressor CFM Refers to the volume
or rate of air flow the compressor will deliver in Cubic Feet
per Minute.
Air Compressor Cut In PSI Air receiver PSI at
which the pump starts or goes out of bypass.
Air Compressor Discharge Line Tubing, pipe or
hose from the pump outlet to the air system.
Air Compressor Displacement The rate at
which dead air is replaced by compressed air.
Air Compressor Light Duty These units are designed
for jobs that require lower PSI and CFM ratings.
Air Compressor Lubricator A lubricator ensures
proper lubrication of internal moving parts of pneumatic tools.
Air Compressor Manifold All ports are at equal
pressure.
Air Compressor Medium Duty These units are designed
for jobs that require average levels of PSI and CFM.
Air Compressor Parts Air compressor parts are
our specialty. We carry every part for every machine.
Air Compressor Recovery Time The time from
cut in to cut out at no load.
Air Compressor Safety Relief Valve A normally
closed valve that opens when the pressure is greater than the
valve rating.
Air Compressor Single Stage Compression from initial
to final pressure is completed in a single step or piston stroke.
Air Compressor Stages Dividing the total pressure
among two or more cylinders by feeding the exhaust from the
first cylinder (low pressure) to the inlet of the next cylinder
(high pressure).
Air Compressor Two Stage Compression is accomplished
in two steps, passing through a low pressure cylinder through
a cooling coil to a second stage high pressure cylinder for
final compression.
Air Compressor Unloader As the compressor cuts
out, the unloader relieves pressure from the machine. This ensures
that the compressor will not be loaded when the motor/engine
starts.
Air Compressor Volumetric Efficiency The actual
volume capacity compared to the piston displacement. The efficiency
of the pump drops as the pressure goes up.
Air Compressor Water Drain Drains moisture from
the air receiver. This should be done after each use to reduce
corrosion to the tank.
Air Compressor Working Pressure The maximum safe
operation pressure.
Air Dryer A device that removes moisture from
compressed air. Typically accomplished by cooling the air through
refrigerant or a dessicant bed.
Air End Compression chamber on a rotary screw
compressor where air is compressed.
Air Filter Filters out moisture, dust, rust, etc.
Air Receiver The air receiver is simply the air
storage tank.
Air Regulator Allows the user to adjust the PSI
on the compressor.
Air-cooled compressors Atmospheric air is circulated
to cool the unit and /or the compressed air.
Air/Oil Separator Filter designed to remove oil
from compressed air in a rotary screw compressor.
Ambient air The air around or surrounding you.
Amp Rating The measure of strength of an electric
current.
Anti-wear Agent An additive that minimizes wear
caused by metal-to-metal contact during conditions of mild boundary
lubrication.
Approach temperature Temperature above ambient.
Atlas Copco Manufacturer of rotary screw and reciprocating
air compressors.
Atmospheric Pressure The measured ambient pressure
for a specific location and altitude in PSI (pounds per square
inch).
Auto Start/Stop An air compressor with this feature
automatically starts and stops when required, making it more
economical than a constant run unit.
Auto-ignition Temperature Minimum temperature
at which a combustible fluid will burst into flame without an
extraneous ignition source.
Automatic Sequencer A device which operates compressors
in sequence according to a programmed schedule.
Bearing Corrosion Chemical attack on bearing metal
or on one of the metals in a bearing alloy caused by acids evolved
during chemical deterioration of the oil.
Belt Drive The Pump is powered by a belt wrapped
around the motor.
Boosters Increase air pressure (usually four times
inlet PSI).
Capacity The amount of air flow delivered under
specific conditions, usually expressed in cubic feet per minute
(CFM).
Capacity Gauge A gauge that measures air flow
as a percentage of capacity, used in rotary screw compressors.
Centrifugal compressors Compression of air/gas
through turning impellers.
CFM Cubic feet per minute.
Check Valve A valve which permits flow in only
one direction.
Chicago Fitting (crows foot) 1/4 turn fitting
that can connect hose to a compressor or extend the length of
hose used to flow gases.
Clearance Pocket An auxiliary volume that may
be opened to the clearance space to reduce the volumetric efficiency
of a reciprocating compressor.
Compressibility A factor expressing the deviation
of a gas from the laws of thermodynamics.
Compression Ratio The ratio of the absolute discharge
pressure to the absolute inlet pressure.
Compression, Adiabatic Compression in which no
heat is transferred to or from the gas during the compression
process.
Compression, Isothermal Compression is which the
temperature of the gas remains constant.
Compression, Polytropic Compression in which the
relationship between the pressure and the volume is expressed
by the equation PVn is a constant.
Condensate Liquid discharged from compressor and
/or air treatment equipment.
Constant Run An air compressor with this feature
will not stop automatically and will therefore run regardless
of whether it is needed or not.
Constant Speed Control A system in which the compressor
is run continuously and matches air supply to air demand by
varying compressor load.
Corrosion The chemical change in the mechanical
elements caused by the interaction of fluid or contaminants,
or both. More specifically related to chemical changes in metals.
Critical Pressure The limiting value of saturation
pressure as the saturation temperature approaches the critical
temperature.
Crude Oil Naturally occurring hydrocarbon fluid
that contains small amounts of nitrogen, oxygen, and sulfur
derivatives and other impurities.
cSt Abbreviation of centistoke.
Cubic Feet per Minute (CFM) A measurement of the
rate of flow of gas leaving the air compressor.
Cut-In/Cut-Out Pressure Respectively, the minimum
and maximum discharge pressures at which the compressor will
switch from unload to load operation(cut in) or from load to
unload (cut out).
Cycle The series of steps that a compressor with
unloading performs; 1) fully loaded, 2) modulating, 3) unloaded,
4) idle.
Cycle Time Amount of time for a compressor to
complete one cycle.
Cylinder Double Acting A cylinder in which pressure
can be applied to the movable piston rod in either direction.
Cylinder Single Acting A cylinder in which pressure
can be applied to the piston in only one direction.
Decibel (db) A measurement of noise.
Degree of Intercooling The difference in air or
gas temperature between the outlet of the intercooler and the
inlet of the compressor.
Deliquescent Melting and becoming a liquid by
absorbing moisture.
Demand Flow of air at specific conditions required
at a point or by the overall facility.
Demulsibility Test time required for a specified
oil-water emulsion to break, ASTM D 1401.
Desiccant A material having a large proportion
of surface pores, capable of attracting and removing water vapor
from the air.
Detergent An additive in lubricants generally
combined with (and confused with) dispersant additives.
Dew Point The temperature at which moisture in
the air will begin to condense if the air is cooled at constant
pressure. At this point the relative humidity is 100%.
Dew point suppression Temperature below ambient.
Diaphragm A stationary element between the stages
of a multi-stage centrifugal compressor.
Diaphragm Cooling A method of removing heat from
the flowing medium by circulation of a coolant in passages built
into the diaphragm.
Diffuser A stationary passage surrounding an impeller,
in which velocity pressure imparted to the flowing medium by
the impeller is converted into static pressure.
Direct Drive The pump is powered directly by the
motor.
Discharge Pressure Air pressure produced at a
particular point in the system under specific conditions measured
in PSI (pounds per square inch).
Discharge Temperature The temperature at the discharge
flange of the compressor.
Displacement The volume swept out by the piston
or rotor(s) per unit of time, normally expressed in cfm.
Drip-Proof Electric Motors These motors will have
all of its cooling vents situated so that any dust or moisture
will not be able to contaminate the innards of the motor.
Dynamic Type Compressors Compressors in which
air or gas is compressed by the mechanical action of rotating
impellers imparting velocity and pressure to a continuously
flowing medium.
Efficiency Any reference to efficiency must be
accompanied by a qualifying statement which identifies the efficiency
under consideration, as in the following definitions of efficiency
Efficiency, Compression Ratio of theoretical power
to power actually imparted to the air or gas delivered by the
compressor.
Efficiency, Isothermal Ratio of the theoretical
work (as calculated on a isothermal basis) to the actual work
transferred to a gas during compression.
Efficiency, Mechanical Ratio of power imparted
to the air or gas to brake horsepower (bhp).
Efficiency, Polytropic Ratio of the polytropic
compression energy transferred to the gas, to the actual energy
transferred to the gas.
Efficiency, Volumetric Ratio of actual capacity
to piston displacement.
Electric Air Compressor A compressor driven by
an electric motor.
Electric Motor Efficiency How efficiently the
motor turns electrical energy into mechanical energy.
Electric Motor Enclosure The housing around the
motor available in drip-proof, totally enclosed, and explosion
proof.
Electric Motor Frame The configuration on the
baseplate of the motor.
Electric Motor Multi-Speed Multi-speed motors
are designed for two or more definite rates of speed remaining
practically constant regardless of load changes.
Electric Motor Service Factor The amount of additional
horsepower over and above a motor’s listed rating that it can
deliver when necessary as a protection against overload.
Electric Motor Synchronious Speed The speed at
which a motor will operate if the rotor turns at exactly the
speed of the magnetic field that drives the rotor.
Emulsion A mechanical mixture of two mutually
insoluble liquids (such as oil and water).
Ester A compound generally formed by the reaction
of an alcohol with an organic acid. Esters were among the earliest
types of synthetic lube oils; they are still widely used in
this application.
Exhauster A term sometimes applied to a compressor
in which the inlet pressure is less than atmospheric pressure.
Filters Devices for separating and removing particulate
matter, moisture or entrained lubricant from air.
Flange Connection The means of connecting a compressor
inlet or discharge connection to piping by means of bolted rims
(flanges).
Flash Point Minimum temperature of a petroleum
product or other combustible fluid at which vapour is produced
at a rate sufficient to yield a combustible mixture.
Foam Inhibitor An additive which causes foam to
dissipate more rapidly.
Foaming May occur when a liquid is intimately
mixed with air.
Free Air Air at atmospheric conditions at any
specified location, unaffected by the compressor.
Full-Load Air compressor operation at full speed
with a fully open inlet and discharge delivering maximum air
flow.
Gardner Denver Manufacturer of rotary screw and
reciprocating air compressors.
Gas One of the three basic phases of matter. While
air is a gas, in pneumatics the term gas normally is applied
to gases other than air.
Gauge Pressure The pressure determined by most
instruments and gauges, usually expressed in psig. Barometric
pressure must be considered to obtain true or absolute pressure
(PSIG).
High-pressure air Compressed air above 150 PSI.
Horsepower (HP) A measurement of power output.
Combined with the CFM, this gives an idea of performance.
Horsepower, Brake Horsepower delivered to the
output shaft of a motor or engine, or the horsepower required
at the compressor shaft to perform work.
Horsepower, Indicated The horsepower calculated
from compressor indicator diagrams. The term applies only to
displacement type compressors.
Horsepower, Theoretical or Ideal The horsepower
required to isothermally compress the air or gas delivered by
the compressor at specified conditions.
Humidity, Relative The relative humidity of a
gas (or air) vapor mixture is the ratio of the partial pressure
of the vapor to the vapor saturation pressure at the dry bulb
temperature of the mixture.
Humidity, Specific The weight of water vapor in
an air vapor mixture per pound of dry air.
Hysteresis The time lag in responding to a demand
for air from a pressure regulator.
Impeller The part of the rotating element of a
dynamic compressor which imparts energy to the flowing medium
by means of centrifugal force. It consists of a number of blades
which rotate with the shaft.
Indicated Power Power as calculated from compressor
indicator diagrams.
Indicator Card A pressure-volume diagram for a
compressor or engine cylinder, produced by direct measurement
by a device called an indicator.
Inducer A curved inlet section of an impeller.
Ingersoll Rand Manufacturer of rotary screw and
reciprocating air compressors.
Inlet cfm (icfm) Cfm flowing through the compressor
inlet filter or inlet valve under rated conditions.
Inlet Pressure The actual pressure at the inlet
flange of the compressor typically measure in PSIG.
Instrument-quality (IQ) air Treated compressed
air from an oil-flooded compressor (aftercooled, filtered).
Intercooler The intercooler cools the compressed
air as it travels from one stage to the next higher stage.
Intercooling The removal of heat from air or gas
between compressor stages.
Intercooling, Degree of The difference in air
or gas temperatures between the inlet of the compressor and
the outlet of the intercooler.
Intercooling, Perfect When the temperature of
the air or gas leaving the intercooler is equal to the temperature
of the air or gas entering the inlet of the compressor.
Joy Manufacturer of rotary screw and reciprocating
air compressors.
Kaeser Manufacturer of rotary screw air compressors.
Leak An unintended loss of compressed air to ambient
conditions.
Leroi Manufacturer of rotary screw and reciprocating
air compressors.
Liquid Piston Compressor A compressor in which
a vaned rotor revolves in an elliptical stator, with the spaces
between the rotor and stator sealed by a ring of liquid rotating
with the impeller.
Load Factor Ratio of average compressor load to
the maximum rated compressor load over a given period of time.
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.
Low Oil Shutdown An air compressor with this feature
will shut down when the oil level is low, preventing any damage
to the unit.
Low-pressure air Compressed air 150 PSI or lower.
Lubricator A device which adds controlled or metered
amounts of lubricant into a pneumatic system.
Lubricity A moderate load-carrying ability over
and above that indicated by an oils viscosity.
Microns Measurement used to define particulates
in the air stream (one micron = one millionth of a meter, about
one eighth the thickness one human hair).
Modulating Control System which adapts to varying
demand by throttling the compressor inlet proportionally to
the demand.
Motor Bearings Support both ends of the motor
shaft allowing it to rotate smoothly with a minimum of wear
and friction.
Multi-Casing Compressor Two or more compressors,
each with a separate casing, driven by a single driver, forming
a single unit.
Multi-Stage Axial Compressor A dynamic compressor
having two or more rows of rotating elements operating in series
on a single rotor and in a single casing.
Multi-Stage Centrifugal Compressor A dynamic compressor
having two or more impellers operating in series in a single
casing.
Multi-Stage Compressors Compressors having two
or more stages operating in series.
Neut Number Short for neutralization number: the
specific quantity of reagent required to “neutralize” the
acidity or alkalinity of a lube oil sample.
Oil Free A unit described as ‘oil-free’ does
not require oil to run, greatly reducing maintenance costs.
Oil Lubricated An ‘oil-lubricated’ air compressor
keeps the pump cooler, allowing it to run for longer.
Oil/Water Separator Device used to remove oil
from air compressor condensation.
Oil-flooded air Compressed air produced by a compressor
that utilizes lubricating oil in the compression cycle.
Oil-free air Compressed air produced by a compressor
with no oil present in the compression cycle.
Oxidation A form of chemical deterioration to
which petroleum products like most other organic materials are
subject.
Oxidation Inhibitor Chemical added in small quantities
to a petroleum product to increase its oxidation resistance
and, hence, to lengthen its service or storage life.
Palatek Manufacturer of rotary screw and reciprocating
air compressors.
Particulates Any solid material, such as dirt,
rust, weld fines, pollen, etc., that is in the air stream.
Perfect Intercooling The condition when the temperature
of air leaving the intercooler equals the temperature of air
at the compressor intake.
Performance Curve Usually a plot of discharge
pressure versus inlet capacity and shaft horsepower versus inlet
capacity.
Petroleum Term applicable to crude oil and the
hydrocarbon products and materials that are derived from it.
Piston Displacement The volume swept by the piston;
for multistage compressors, the piston displacement of the first
stage is the overall piston displacement of the entire unit.
Pneumatic Tools Tools that operate by air pressure.
Positive Displacement Compressors Compressors
in which successive volumes of air or gas are confined within
a closed space and the space mechanically reduced, resulting
in compression.
Pour Point A widely used low-temperature flow
indicator and is 5 degrees above the temperature to which a
normally liquid petroleum product maintains fluidity.
Power, Theoretical (Polytropic) The mechanical
power required to compress polytropically and to deliver, through
the specified range of pressures, the gas delivered by the compressor.
POWERSOLV Lubricant additive designed to clean
a compressors oil system.
PPM Parts per million, measurement of the oil
present in compressed air.
Pressure Force per unit area, measured in pounds
per square inch (PSI).
Pressure Dew Point For a given pressure, the temperature
at which water will begin to condense out of air.
Pressure Drop Loss of pressure in a compressed
air system or component due to friction or restriction.
Pressure Range Difference between minimum and
maximum pressures for an air compressor. Also called cut in-cut
out or load-no load pressure range.
Pressure Rise The difference between discharge
pressure and intake pressure.
Pressure Switch A pressure switch has preset cut
in/cut out pressure points to control engine/motor.
Pressure, Absolute The total pressure measured
from absolute zero (i.e. from an absolute vacuum).
Pressure, Discharge The pressure at the discharge
connection of a compressor.
Pressure, Intake The absolute total pressure at
the inlet connection of a compressor.
Pressure, Static The pressure measured in a flowing
stream in such a manner that the velocity of the stream has
no effect on the measurement.
Pressure, Total The pressure that would be produced
by stopping a moving stream of liquid or gas. It is the pressure
measured by an impact tube.
Pressure, Velocity The total pressure minus the
static pressure in an air or gas stream.
PSI Pounds per square inch (unit for pressure
of compressed air).
Pump The mechanical device that compresses air
within the unit.
Quincy Manufacturer of rotary screw and reciprocating
air compressors.
Quick Disconnect A coupling which can quickly
join or separate a fluid line without the use of tools or special
devices.
Rated Capacity Volume rate of air flow at rated
pressure at a specific point.
Rated Flow The maximum flow that the power supply
system is capable of maintaining at a specific operating pressure.
Rated Pressure The operating pressure at which
compressor performance is measured.
Receiver A vessel or tank used for storage of
gas under pressure. In a large compressed air system there may
be primary and secondary receivers.
Reciprocating Compressor Compressor in which the
compressing element is a piston having a reciprocating motion
in a cylinder.
Relative Humidity The ratio of the partial pressure
of a vapor to the vapor saturation pressure at the dry bulb
temperature of a mixture.
Required Capacity Cubic feet per minute (cfm)
of air required at the inlet to the distribution system.
Rotary compressors Compression is produced by
the positive action of rotating elements.
Rotor The rotating element of a compressor.
Rust Inhibitor A lubricant additive for protecting
ferrous (iron & steel) components from rusting caused by
water contamination or other harmful materials from oil degradation.
SCFM Standard cubic feet per minute.
Screw Type Compressor This compressor has two
intermeshing helical rotors enclosed in a housing with an inlet
port at one end and a discharge port at the other end.
Seals Devices used to separate and minimize leakage
between areas of unequal pressure.
Sequence The order in which compressors are brought
online.
Service Pressure The range of pressure in the
pressure tank during the pumping cycle, usually expressed in
pounds per square inch gauge.
Shaft Seal A device mounted on the drive shaft
between the impeller or airend and the inside pump housing which
creates an air tight chamber within the housing.
Shaft The part by which energy is transmitted
from the prime mover through the elements mounted on it, to
the air or gas being compressed.
Shutoff Valve A valve which operates fully open
or fully closed.
Sole Plate A pad, usually metallic and embedded
in concrete, on which the compressor and driver are mounted.
Specific gravity The ratio of the specific weight
of air or gas to that of dry air at the same pressure and temperature.
Specific Humidity The weight of water vapor in
an air-vapor mixture per pound of dry air.
Specific Power A measure of air compressor efficiency,
usually in the form of bhp/100 acfm.
Specific Weight Weight of air or gas per unit
volume.
Speed The speed of a compressor refers to the
number of revolutions per minute (rpm) of the compressor drive
shaft or rotor shaft.
Stages A series of steps in the compression of
air or a gas.
Standard air Air at a temperature of 68F, 14.70
PSI atmospheric pressure, and relative humidity of 36% (per
ASME). In the gas industry, temperature is 60F.
Standard compressed air Untreated compressed air
from an oil-flooded system (not after-cooled or filtered).
Start/Stop Control A system in which air supply
is matched to demand by the starting and stopping of the unit.
Stationary Air Compresor A unit that cannot be
moved & is usually electric driven.
Sullair Manufacturer of rotary screw and reciprocating
air compressors.
Sullube 32 Synthetic compressor lubricant used
mainly in Sullair air compressors.
Surge A phenomenon in centrifugal compressors
where a reduced flow rate results in a flow reversal and unstable
operation.
Surge Limit The capacity in a dynamic compressor
below which operation becomes unstable.
Temperature Rise Ratio The ratio of the computed
isentropic temperature rise to the measured total temperature
rise during compression.
Temperature, Absolute The temperature of air or
gas measured from absolute zero. It is the Fahrenheit temperature
plus 459.6 and is known as the Rankin temperature.
Temperature, Discharge The total temperature at
the discharge connection of the compressor.
Temperature, Inlet The total temperature at the
inlet connection of the compressor.
Temperature, Static The actual temperature of
a moving gas stream. It is the temperature indicated by a thermometer
moving in the stream and at the same velocity.
Temperature, Total The temperature which would
be measured at the stagnation point if a gas stream were stopped,
with adiabatic compression from the flow condition to the stagnation
pressure.
Theoretical Power The power required to compress
a gas isothermally through a specified range of pressures.
Torque A torsional moment or couple. This term
typically refers to the driving couple of a machine or motor.
Total Package Input Power The total electrical
power input to a compressor, including drive motor, belt losses,
cooling fan motors, VSD or other controls, etc.
Totally Enclosed Electric Motors These motors
will be used in applications similar to drip-proof motors and
are recommended for any outdoor use.
Two-stage compressors Two-compression chambers
(initial to intermediate) with one air discharge.
Ultracoolant Synthetic compressor lubricant used
mainly in Ingersoll Rand rotary screw air compressors.
Unit Type Compressors Compressors of 30 bhp or
less, generally combined with all components required for operation.
Unload (No load) Compressor operation in which
no air is delivered due to the intake being closed or modified
not to allow inlet air to be trapped.
Vacuum Pumps Compressors which operate with an
intake pressure below atmospheric pressure and which discharge
to atmospheric pressure or slightly higher.
Valves Devices with passages for directing flow
into alternate paths or to prevent flow.
Vapour Pressure Measure of liquid’s volatility.
Viscosity A measure of the internal friction or
the resistance of a fluid to flow.
Viscosity Index (V.I.) Measure of the rate of
change of viscosity with temperature.
Voltage Voltage is the measurement of electrical
force. It is the force that delivers current when electricity
is applied to an electrical device.
Volute Stationary, spiral shaped passage which
converts velocity head to pressure in a flowing stream of air
or gas.
Water-Cooled Compressor Compressors cooled by
water circulated through jackets surrounding cylinders or casings
and/or heat exchangers between and after stages.
Whipcheck Safety cable used to restrain air hoses
if an end breaks.
Working Pressure The pressure which overcomes
the resistance of the working device.
Worthington Manufacturer of rotary screw and reciprocating
air compressors.
Address: 74, Yuram-ro, Dong-gu, Daegu, Korea [MY MAIL]
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