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Compressed Air Glossary of Terms :: C ::
Glossary Index
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Can velocity
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The velocity of the gas in the passages between the filter units in the
filter house of a gas filter.
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Cap
-
The pressure screw cover and/or lever housing on a valve. May
be screwed, bolted. packed, or plain lever.
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Capacity
-
Capacity of a compressor is the full rated volume of flow of
gas compressed and delivered at certain set
conditions.
-
Capacity filtration
-
The amount of air that a filter can handle. Expressed in
CFM.
-
Capacity gauge
-
A gauge that measures air flow as a percentage of capacity,
used in rotary screw compressors as an estimator during modulation
controls.
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Capillary tube
-
A restrictive tube used in a refrigeration system which
restricts the flow of freon and allows pressure to build on one
side and suction on the other. It is located between the condenser
and the evaporator.
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Cap tube
-
A restrictive tube used in a refrigeration system which
restricts the flow of freon and allows pressure to build on one
side and suction on the other. It is located between the condenser
and the evaporator.
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Carbonate
-
A salt or ester of carbonic acid.
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Carbon dioxide
-
A heavy colorless gas that does not support combustion but is
formed by the combustion and decomposition of organic substances.
Found in some ambient air conditions.
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Carbon monoxide
-
A colorless odorless very poisonous gas formed by the
incomplete burning of carbon. Found in some ambient air
conditions.
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Carbon residue
-
The carbon left after evaporating an oil under controlled
conditions.
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Casing
-
The pressure containing stationary element that encloses the
rotor and associated internal components of a compressor,
including integral inlet and discharge connections.
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Celsius
-
°C The international temperature scale where water
freezes at 0 (degrees) and boils at 100 (degrees). Also known as
the centigrade scale.
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Center tube
-
The internal duct and filter medium support
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Centrifugal
compressor
-
A dynamic compressor. A machine in which air or gas is
compressed by the mechanical action of rotating vanes or impellers
imparting velocity and pressure to the air or gas. In a
centrifugal compressor, flow is in a radial direction. Air enters
the compressor through the machine mounted inlet control valve and
flows to the first stage where the impeller imparts velocity
energy to the air. The air then proceeds through a diffuser
section which converts the velocity energy to pressure energy. A
multistage centrifugal compressor is a machine having two or more
of these stages.
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CFM
-
ACRONYM
- Cubic feet per minute. An airflow measurement of volume.
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Charle's law
-
States that the volume of a gas, at constant pressure, varies
directly with the absolute temperature.
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Chatter
-
Abnormal, rapid reciprocating movement of the disc on the seat
of a pressure relief valve.
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Chip control
-
a filter intended to prevent only large particles from
entering a component immediately downstream.
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Chipping hammer
-
A hand held pneumatic tool. Designed to chip masonry, plaster,
concrete etc.
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Check valve
-
A valve that permits flow in one direction only.
-
Chlorine
-
A chemical element that is a heavy strong smelling greenish
yellow imitating gas used as a bleach, oxidizing agent and
disinfectant. Found in some ambient air conditions.
-
Chlorofluorocarbons (CFCs)
-
Compounds containing chlorine, fluorine or bromine, used as aerosol
propellants, refrigerants, foaming agents and solvents and which, on
decomposition by sunlight, produce oxides of chlorine responsible for the
removal of ozone from the stratosphere.
-
-
Choke
-
This term is used for turbo compressors and represents the
maximum flow condition. It is sometimes also referred to as
stonewalling.
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Cleanable
-
A filter element which, when loaded, can be restored by a
suitable process, to an acceptable percentage of its original dirt
capacity.
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Cleanliness level
-
a measure of relative freedom from
contaminants.
-
Clean room
-
A facility or enclosure in which air content and other
conditions (such as temperature, humidity, and pressure) are
controlled and maintained at a specific level by special
facilities and operating processes and by trained personnel.
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Clean pressure drop
-
The pressure loss across the filter element determined under
steady state flow conditions using a clean test fluid across a
clean filter element.
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Clearance
-
The maximum cylinder volume on a working side of the piston,
minus the piston displacement volume per stroke. It is usually
expressed as a percentage of the displace volume.
-
Clearance pocket
-
An auxiliary volume that may be opened to the clearance space
for increasing the clearance, usually temporarily, to reduce the
volumetric efficiency of the compressor.
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Clevis
-
A device for mounting cylinders.
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Collapse
-
An inward structural failure of a filter element which can
occur due to abnormally high pressure drop (differential pressure)
or resistance to flow.
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Collapse pressure
-
The minimum differential pressure that an element is designed
to withstand without permanent deformation.
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CNG
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ACRONYM
- Compressed natural gas, primarily methane.
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Closed loop system
-
A system in which distilled water, antifreeze, and/or
corrosion inhibitors are circulated through a collector and
storage tank in a closed loop. Heat picked up from the collector
by the circulating fluid is transferred to the storage tank
through the closed loop or other heat exchangers.
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Coalescing filter
-
A filter unit that combines three principles to filter out oil
aerosols: 1)
Direct interception
- A sieving action, 2)
Inertial impaction
- Collision with filter media fibers, 3)
Diffusion
-Particles travel in a spiral motion, presenting
an effective frontal area thus capturing particles within the
filter medium.
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Code
-
The A.S.M.E. Boiler and Pressure Vessel Code.
-
Coefficient of
discharge
-
The ratio of the measured relieving capacity to the
theoretical relieving capacity.
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Cold
differential test procedure
-
Actual gage pressure on the test stand that includes
correction factors for temperature, pulsation, vibration, constant
back pressure, etc.
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Cold start
-
Starting a compressor from a state of total shutdown. Usually
done with "local" control at the compressor. May be done with
"remote" control, but only advised with "heavy" instrumentation
and monitoring accessories.
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Compensator
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An expansion joint designed to take up thermal expansion.
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Composition of air
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A colorless, odorless, tasteless gas. A mixture of individual
gases. The gaseous mixture surrounding the earth..
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Compressed
-
To reduce the volume of, by or as if by pressure.
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Compressed air
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Air under pressure greater than that of the atmosphere.
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Compressed air
challenge
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A public/private initiative to promote the efficiency of
compressed air in the US.
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Compressibility
-
A factor expressing the deviation of gas from the laws of
hydraulics.
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Compressibility
factor Z
-
Is the ratio of the actual volume of the gas to the volume
determined according to the perfect gas law.
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Compression
adiabatic
-
Compression in which no heat is transferred to or from the gas
during the compression process.
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Compression
efficiency
-
Is the ratio of the theoretical work requirement to the actual
work required to be performed on the gas for compression and
delivery.
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Compression Isothermal
-
Is a compression in which the temperature of a gas remains
constant.
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Compression ratio
-
The ratio of the absolute discharge pressure to the absolute
inlet pressure.
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Compressor
-
A machine that compresses air, gases.
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Computer control
-
May be "local" using a micro-processor or "remote" using a PC
(Personal Computer) or "larger" computer. Only recommended where
large "swings" in system (process) demand amplitude may occur.
Very effective where "load shaping" is an important consideration.
"Heavy" monitoring and instrumentation accessories required for it
to be efficient and effective. Usually not necessary where system
demand is predominantly constant.
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Condensate
-
the liquid that separates from a vapor during condensation.
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Condenser
-
A device that changes a vapor into a liquid. Accomplished by
exposing a tube containing vapor to air or by passing the tube
through a water jacket.
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Conduction
-
The transfer of heat energy through a material (solid, liquid,
or gas) by the motion of adjacent atoms and molecules without
gross displacement of the particles.
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Connector
-
The mating device that is inserted into the coupler of a quick
coupler and locked to complete the connection. Also referred to as
plug or nipple.
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Constant speed
control
-
The unit that runs continuously and matches air supply to
demand, by loading and unloading the compressor.
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Contaminant
-
Foreign matter carried in the air, gas or fluid to be filtered
out. Includes air borne dirt, metallic particles produced by wear
of moving parts of the air compressor, rust from metal
pipelines.
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Contaminant capacity
-
the weight of a specified artificial contaminant that must be
added to the influent to produce a given differential pressure
across a filter at specified conditions. Used as an indication of
relative service life.
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Contaminant failure
-
any loss of performance due to the presence of contamination.
Two basic types of contamination failure are: Perceptible --
gradual loss of efficiency or performance, and Catastrophic --
dramatic, unexpected failure.
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Control valve
-
A valve that controls the flow in air lines.
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Convection
-
Is a means of transferring heat through mass flow. Also the
transfer of heat within a fluid by movements within the
fluid.
-
Convolution
-
On a bellow type air actuator, that part of the flexible
member forming an annular protrusion larger than the O.D. of the
end retainers or bead rings.
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Coolant
-
Fluid cooling agent.
-
Cooling tower
-
A cooling water supply system. There are two different types -
Open and closed loop systems.
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CPM
-
ACRONYM
- Cycles per minute - a unit of measure of the frequency of any
vibration.
-
Cracking
-
To subject petroleum oil to heat for breaking down into
lighter products.
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Critical pressure
-
Is the saturation pressure at the critical temperature. It is
the highest vapor pressure that the liquid can exert.
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Critical speed
-
Rotative speeds at which rotating machinery-axial or screw lobe-pass
through unbalanced operation.
-
Critical temperature
-
The highest temperature at which well-defined liquid and vapor
states exist.
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Crosshead assembly
-
The assembly connecting the crankcase and connecting rod to the cylinder head
and piston rod for translating circular to linear motion.
-
Crosshead compressor
-
A compressor belonging to the group of displacement
reciprocating compressors.
-
Crosshead loading
-
The tensile or compressive loading on the crosshead assembly with
compressive piston rod loading on the outward stroke and tensile piston
rod loading on the inward stroke.
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CSA
-
ACRONYM
- Canadian Standards Association
-
CTD
-
ACRONYM
- Approach temperature. Usually the difference between cooling
water temperature in to compressed air temperature out of an
inter-cooler or after-cooler. Sometimes used to define oil cooler
efficiency (cooling water temperature in to oil temperature out)
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Cubic feet per
minute (CFM)
-
CFM. An airflow measurement of volume.
-
cu m/sec
-
A volume. Cubic meters per second.
-
Cut in cut out
pressure
-
The settings on a pressure switch used to either load or
unload the air compressor on a constant speed application, or
start or stop the compressor on a start/stop application. The cut
out pressure is also known as the maximum pressure, or the point
at which there is no air being delivered. The cut in pressure is
referred to as the minimum pressure, or the pressure that the
system is allowed to fall to before air volume is required.
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Cycle
-
A single complete operation consisting of progressive phases
starting and ending at the neutral position.
-
Cycle time
-
Amount of time for a compressor to complete one
cycle.
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Cylinder
-
The piston chamber in a compressor or actuator.
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Cyclone
-
a type of separator for removal of larger particles from an exhaust gas
stream. Gas laden with particulates enters the cyclone and is directed to
flow in a spiral causing the entrained particulates to fall out and collect
at the bottom. The gas exits near the top of the cyclone.
-
-
Cyclone separator
-
A means of purifying an air stream by using both gravitational and
centrifugal forces.
Glossary Index
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B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Thanks to Impact RM for permission to reprint the glossary.
Compressed Air Glossary © Impact RM
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