Download Compressed Air Basics rev 0606

Compressed Air Basics
*The following information is intended as a General Overview in order to aid our
valued customers in understanding the basics of the Air Compressor System. It
is not intended to be exhaustive or a substitute for professional system
evaluation, equipment suitability, installation or repair. The reader/user assumes
all risks, if any, such as the risk of any direct, indirect or consequential loss, injury
or damage arising out of the use of this information. Installation and repair of
equipment should be done by qualified personnel.
**A qualified Electrician should perform all electrical repairs or inspections.
***Important Note : The following topics are in alphabetical order. Please note
that any word typed in “BOLD” indicates a Topic Subject and suggests that the
reader may wish to see that Topic.
TOPICS
A.S.M.E.: An Acronym for American Society of Mechanical Engineers.
Air Receiver Tanks greater than 6” in diameter MUST meet A.S.M.E.
specifications for Commercial, D.O.T. or Federal use.
A.S.M.E. Receiver Tanks have a fixed identification plate mounted to the tank
showing the ratings of the tank design. Tanks without this plate are NOT
A.S.M.E. rated. See Tank.
After Cooler: Used to cool down the heated compressed air to help reduce the
dew point and allow for moisture extraction from the air stream. Generally used in
advance of a Dryer.
After Coolers in the form of an air to air radiator may be freestanding using a fan
or mounted on the belt guard in front of a fan type flywheel. On Rotary Screw
Units, the after coolers are usually an integral part of the unit cooling system.
After Coolers also include Finned copper tubes between the Pump exhaust and
the Tank inlet. Water Cooled after coolers use water in a heat exchanger jacket.
Air Compressor: General. Any device that compresses atmospheric air. If the
customer intends to compress gas or liquid of any type they should advise their
ACS representative. Special Compressors and equipment are required.
Air Compressor Types : The following are listed under their own topics:
Reciprocating, Rotary Screw, Rotary Vane, Centrifugal, Vacuum, Single
Stage, Two Stage, Gas Powered, Diesel Powered, Electric Powered,
Oilless, Direct Drive, Belt Drive, Aluminum, Cast Iron.
Air Demand: or Load. The CFM requirement at specified PSI for equipment or
tools using air. This is important when sizing a compressor. See Air Tools, Sand
Blasters
Air End: A term that refers to the component that does the actual compressing.
Usually refers to Rotary Screw and Rotary Vane type compressors.
Air Leaks: Even small air leaks will reduce the performance of your air system
and dramatically drive up your operating costs. For Example, a 1/16” leak at 100
PSI will lose approximately 70,000 CFM of air in a single week ! A plant with
several small leaks could add up to thousands of dollars lost in electrical cost
alone over a years time.
Air System: A term to describe the total air system which includes; The air
compressor unit or units, manifolds and piping, air treatment devices, air
equipment and tools.
Air Tools: Any tool or device that uses air as the driving force. The air
requirements and recommended regulated pressure is very important for proper
tool function.
Following are average CFM requirements for selected air tools;
Blow Gun = 3 CFM, 3/8” Impact = 3 CFM, 1/2” impact = 4 CFM, 3/4” CFM = 8
CFM, 1”impact = 12 CFM, Orbital Sander = 5 CFM,
Painting = 5 to 20 CFM.
Consult the manufacturer of your air tool or device for exact requirements. As
tools wear, if used at the wrong pressure or without a line Regulator, air demand
will increase.
Air Tool Oil: A special lubricant used in “air tools” and “air motors”.
See Lubricator.
Air Treatment: The primary byproducts of compressed air are:
• Heat
• Water Vapor
• Oil Vapor
• Suspended Particulate’s.
The devices for treating the delivered air include: Filters, Regulators,
Lubricators, Coalescers, After Coolers, Refrigerated Dryers, Desiccant
Dryers and more.
An ACS representative can assist you in the most economical method to treat
your delivered air according to your specific needs.
ALL IN ONE: Pilot Valve/Dump Valve. A combination valve used mostly on
constant run units. It functions as a Pilot Valve, Check Valve and Exhaust valve.
Useful where the pump does not have head unloaders. This valve allows the unit
to remain running. When the pressure level reaches a preset level , the valve
opens and dumps the excess pressure to atmosphere and sends an air signal to
the idler in gas engine applications. When the pressure drops in the storage tank
the valve closes the exhaust port and resumes air flow to the tank.
Aluminum Compressor: A common material used primarily in domestic or
hobby type compressors. Reduces cost and weight. The aluminum pumps may
not have as long a life span as a heavier and tougher “all cast iron” pump. Some
pumps use a combination of cast iron and aluminum parts which tend to be
higher quality.
Automatic Tank Drain: There are several types. Pneumatic: is triggered from
the pressure differential of a compressor cycle. Electronic: uses 115 volts and
can be adjusted for interval and duration of drain time. Float Type: triggered by a
float and water valve assembly.
Ball Valve: A Line valve or Tank service valve that uses a stainless steel ball
contained inside a brass body valve. Operates with a handle that swings 90
degrees to full open. Simple and reliable.
Belt Drive: A system where belts are used between the power source and the
compressor. This is the most frequently used system. The main advantage is
simplicity and ease of repair.
Beltguard: ACS offers “all metal” beltguards. Insurance and OSHA require that
your compressor belts be protected from accidental contact .
Bucket High Tank Drain: A type of drain valve that uses a flexible dip tube.
Mounted into the side port of a tank rather than a bottom port. The dip tub
reaches the bottom of the tank to evacuate condensate.
Cast Iron Compressor: Cast Iron is the preferred and most common material for
compressor construction. It offers long life and durability and lends itself to
rebuilding in much the same way one would rebuild a car engine.
Centrifugal Compressor: Also known as a Blower. Compression is
accomplished by means of a fan or turbine type blade. May involve multiple
stages to increase pressure ratings. Used in applications requiring a large
volume of air flow but usually at relatively lower pressures. An ACS
representative can assist you in determining if this type of unit would apply to
your specific situation.
Centrifugal Separator: A Cast Iron Condensate water trap used on larger units.
Uses a centrifugal air flow within the collection chamber to sling water out of the
air stream. Our Wright Austin Model includes an automatic float drain.
In sizes from 1” to 3”.
CFM: Cubic feet per minute. Compressors are rated by CFM. It is very important
that you know what the delivered CFM is at a specific pressure when comparing
compressors. Some dealers may advertise CFM displacement which is always
higher than CFM delivered. Another key is the pressure given. A CFM rating at
40 PSI will always be a higher value than at 100 PSI or 175 PSI. The main thing
to remember is Delivered CFM at the same Pressures when comparing
performance. See PSI.
Choosing a Compressor: The choice of a specific model and type of
compressor is based upon several key factors.
These include;
• The total expected air demand in CFM on a routine daily basis.
• The duty cycle of the load demand versus the designed duty cycle of the unit.
• Number of employees.
• The required system pressure.
• The available power.
• The specific air treatment requirements.
• Any special application requirements.
An ACS representative can help you in planning your system requirements. See
Air Compressor types. See Duty Cycle. See Air Tools. See Air Treatment.
See Compressor Class.
Check Valve: A one way valve. The check valve prevents air flow from reversing
or backing up. Check valves are used to contain and hold the air pressure in the
storage system preventing it from backing out past the Pump or Air End after the
unit shuts down. More importantly , the Check valve allows the unloader to do its
job by isolating the Pump or Air End from the storage system. See Unloader.
ACS offers an extensive selection of check valves. Since there are several types
of designs . You need to know the basic design of your valve.
• Are the threads male or female? Or a combination of the two.
• What are the thread types. NPT or compression?
• Is the Valve mounted externally?
• Is the Valve mounted directly into the tank?
• Is the valve mounted vertically or horizontally.
• Does the valve have a side port for an unloader connection?
Coalescor: A type of in line filter that is designed to extract trace oil from the air
stream. A pre-filter is usually used in advance of the coalescor.
Coiled Hose: A hose that is premolded to be self recoiling to reduce tangles and
kinks. Popular at work stations or air dispensers.
Compressor Class: There are many “unofficial terms” for Class or Type of
Compressors. It is used as a marketing tool. Following are the main Classes.
However, be aware. What you see advertised may not match these descriptions.
• Toy: Usually a small hand held or wheeled unit. Usually Plastic and/or
Aluminum, Direct drive, Single stage and Oilless. Intended for occasional use,
light hobby applications etc.. There are some Toys built on large tanks. It is
still a Toy Class Unit. Usually found at Home Building Supply Stores, In
Cheap Imported Tool Catalog/Tool Dealers and Department Stores.
• Utility: A small unit, wheeled or stationary. Aluminum or Cast Iron, one or two
cylinders, usually 80 gallon and smaller, usually Single Stage , Belt Drive and
Oil lubricated. This type of Unit is built tougher and last longer . Intended for
domestic use. Some light commercial use such as fire control systems or
HVAC controls, farm, trade, hobby applications etc..
• Commercial: Typically an all Cast Iron, Two Stage, Belt Driven, Oil
Lubricated, Tank Mounted Unit. Generally 5-30 HP. Intended for auto tire
shops, repair garages, light manufacturing, roadside service, paint and body
shops, and many more.
• Industrial: This class includes Large Reciprocating Pumps, Rotary Screws,
Vanes and Centrifugal Blowers. Intended for a wide variety of manufacturing
and processing plants.
Compressor Pump: A term that refers to the component that does the actual
compressing. Usually refers to Reciprocating pumps. See also Air End.
Control Check Valve: A small 1/4 mpt “in line” check valve used in rotary screw
control systems.
Control Regulator: A special regulator used on Rotary Screw units that control
the output pressure.
Cross Manifold: A pipe fitting that provides for compact piping to multiple
connections. Makes for a neat installation. Useful as a connector for safety
valves gauges etc. ACS offers several variations of manifolds.
Deliquescent Dryer: A type of Dryer that uses melting tablets that absorb
moisture as they melt. The advantage is simplicity. The disadvantage is you
have to change the tablets when they have melted.
Desiccant: A moisture absorption material used in regenerative type dryers.
Usually one of three materials: Silica Gel, Molecular Sieve of crystalline metal
aluminosillcates, and Activated Alumina.
The Activated Alumina is the most commonly used media.
Diesel Powered: ACS offers a 10 HP truck mounted Diesel Unit for road side
service. We also offer a full line of Industrial tow behind and Utility diesels
ranging in outputs of 125 CFM up to 1600 CFM. These units are available for
purchase or RENTAL. Diesels Units are used as back up for large plants and for
many other types of field work such as Government Utility Work , Mining,
Sandblasting etc...
Direct Drive: A construction method by which the motor and pump are
connected directly together. Frequently used to minimize assembly cost and
weight in hobby or domestic compressors. The main drawback is that it makes
repairs more difficult and in some cases the failure of the pump can damage the
motor shaft. Repairs to direct drive home type units may be cost prohibitive as
compared to belt drive units. A direct drive coupler system is also used on many
large industrial compressors. This usually involves rubber members coupled
between the motor and air end.
Displacement: Usually described in cubic feet. This term refers to volume
displacement before compression. Generally it will be a higher value than
delivered air. This can be confusing when comparing compressors. It is always
best to use the delivered air rating at specific PSI levels.
DRAIN: Any of a number of valve designs that are used to manually or
automatically drain away fluids such as condensate and or oil from the
compressed air system components such as Filters, Tanks, Refrigerated Dryers
etc…
These include petcocks, ball valves, auto drains.
Dryer: A term that describes one of several units designed to extract moisture
from the compressed air stream after it has left the compressor but before it
reaches the point of use.
Dryers include : Refrigerated, Desiccant, and Deliquescent.
Dual Control: A term that describes the ability for a motor or engine to continue
to run while the pump or air end is disabled from producing compressed air.
See Unloader: Head Unloading, Dual Control.
Duty Cycle: The “expected demand” for air use , or the “designed” duty cycle of
a compressor as expressed in running time per hour. Typically, Rotary Screws
and Rotary Vanes are designed for 100% duty cycles. Conversely ,
Reciprocating Pumps are designed for an average of 65-75% duty cycles.
Exceeding the designed duty cycle may cause damage to the pump from
overheating. The air demands should be calculated when selecting a
compressor.
An ACS representative can assist you in this calculation.
Electric Powered: Most Compressors are powered by AC electrical power.
However, alternative power sources include Gas or Diesel.
Electrical power availability should be determined when selecting a compressor.
In most home use applications. 115 Volt or 230 Volt Single Phase power is
used. In Commercial or Industrial applications; Three Phase power is the
preferred choice and the most cost effective.
You must determine if your facility is wired for 3 Phase power and at exactly
which voltage. Typically ; 208/230/460. Your Unit will only run on one voltage so
it is vital you know the exact 3 phase voltage. The unit is assembled and wired
based upon the voltage.
If your facility is not wired for three phase you will be limited to no more than 10
HP . Or multiple “single phase” units.
Engines: ACS Offers Gas and Diesel Replacement Engines from 5 Hp to 20 HP.
Engine Driven Units are designed to run continuously since starting and stopping
the engine to control pressure would not be practical.
Engine Driven Compressors use special Idler controls and Pilot Valves.
Filter: Intake. A filter assembly that is mounted on the intake of an air
compressor Pump or Air End. Usually designed to be serviced with a disposable
type filter element. There are Standard and Severe Duty designs for hostile
locations.
Routine filter maintenance is vital to the service life and efficiency of your
compressor. ACS offers a full line of replacement elements and complete air filter
housing assemblies.
Filter: Line or Pipe. An “in line” (compressed air) filter. Generally includes a
water trap bowl and a bowl drain. Part of a FRL or FRC System.
Flex Connector: A stainless steel flexible braided steel pipe with NPT steel
ends. Available in various lengths and pipe sizes.
Used to make the final connections between the unit and other components or to
system piping. Helps reduce and absorb vibration and flexing expansion from
heat or other stress factors.
FRL and FRC System: An acronym for Filter, Regulator and Lubricator or
Filter, Regulator and Coalescor. These are all part of air treatment systems for
compressed air lines. ACS offers a complete line of Air System Treatment
components.
Gas Powered: ACS offers gas powered units ranging from 5 HP for wheeled
hand portables, and 11 through 20 HP units for mounting on service trucks. Gas
powered applications include roadside service, farm field work and construction
job sites where electrical sources are not available or practical.
Gauges: ACS offers a popular selection of pressure gauges to monitor tank and
regulator pressures. Gauges should be replaced at least every three years.
Generator Powered: Where an electrically powered compressor is running off a
portable generator. This is usually a very bad idea. In most cases it is cost
prohibitive because it takes a very large generator to start up and power even a
small compressor. Attempting to under power a compressor will cause motor
burn out and possibly damage the generator.
To make the point; a 5HP (184T) single phase compressor requires a generator
that produces 24,000 watts of power. A small 3/4 hp compressor requires 6000
watts to start up without damaging the motor.
As a general rule ;It is 6 times the “RUN” wattage of the motor when sizing the
generator needed to start the unit.
Glass Beads: A blasting media used in blast cabinets for cleaning rust, paint etc
from small parts. ACS offers 50 # bags of 008 media.
Horse Power: The power rating of an electrical motor. Unfortunately , this is a
very vague and confusing term due to the fact that the “Value” of Horse Power
(HP) is not a constant among the various types and sizes of motors. When
selecting a compressor you should look for the CFM delivered at a specific
pressure. See Choosing a Compressor.
Motors are based upon frame size. The most common among compressors are
56, 145,184,254,256,and 284 among others. The motors usually turn 1750 and
3450 RPM. The 3450 rpm 56 and 145 frame motors are used primarily on the
smaller units. The 1750 rpm motors are used primarily on industrial units. A 1750
rpm motor almost always has a torque value greater than a 3450 rpm motor of
the same labeled horsepower rating. A 5 or 6 HP 56 Frame motor weighs about
40 pounds. While a 5 hp 184 Frame motor weighs about 83pounds. A 5 hp 145
frame has a 4.5 foot pound torque, while a 5 hp 184 frame has a 15 foot pound
torque. As you can see. There is no comparison possible based upon HP labels
alone. Roughly speaking. A 5 hp 184 frame motor is three times the motor when
compared to a 5 hp 56 frame motor.
Hose: Air Hose. ACS offers an assortment of popular lengths and sizes of 250
PSI rated air hose. Used with air tools, roadside service, shops and garages.
We also carry Jack Hammer hose.
Hose Reel: A spring loaded reel that is available from ACS for hoses up to 50 ft.
Can be wall or ceiling mounted. Heavy Duty reels designed for garages and
shops. Features a self locking mechanism that is released by simply tugging on
the hose.
Hydraulic Unloader: A safety device that monitors the oil pressure of the pump.
As the pressure builds up. The device releases the head unloaders and allows
the pump to make air. If the oil level drops for any reason , the pump will unload
and stop making air. This feature forces the attendant to check the unit. Usually
this will save the pump before damage occurs. See Oil Level Safety Switch.
Idler: A device that is usually air operated by an air signal from the Pilot Valve
on Gas or Diesel Units.
The idler device slows the engine down by a mechanical action against the
throttle control when there is no demand for air.
InterCooler: This is a radiator type device constructed either from a finned
copper tube or in a finned cast block. It is an integral part of many two stage
pumps. Its purpose is to help dissipate heat produced from compression between
the first stage ( low pressure ) cylinder and the second stage ( high pressure )
cylinder. The finned copper tube type is considered to be the most efficient.
Inter Staging: Or Single Staging. A malfunction term where one of two stages
of compression is not functioning properly . Most Pumps have an Inter Stage
Safety relief valve. Usually located on the top of the pump. If this valve starts
popping off while the Pump is running, it is warning you that your Pumps “head
valves” need servicing. Failure to service at once may result in damage to your
pump. Do not plug or defeat the safety valve. Defeating the Safety Valve could
result in catastrophic failure of the pump and may cause injury to bystanders.
Other symptoms include overheating, scorched paint on the pump head and low
air output.
LOCATION: Select a clean, dry and well-ventilated location. In cold climates the
compressor should be installed in a heated building. Insulate cold water or other
low temperature pipes that pass overhead to avoid the possible collection and
dripping of condensate onto the compressor and motor that could cause rusting
and/or motor shorting. Do not install the compressor in a boiler room, paint
spray room, auto body sanding area or where sandblasting is carried on. If air in
the area where the compressor is to be installed is acid or dust laden, the
compressor intake should be piped to the outside. This intake pipe should be
increased one pipe size for every twenty (20) feet of run and the modified intake
filters should be installed at the end of the pipes with a hood to protect them from
the elements. Special size filters are required for pipe away. Since all
compressors produce heat. It is important that the unit be placed in an area that
will allow plenty of free flowing air. In warmer climates , many compressors are
installed outside. In these cases the compressor requires a roof overhead to
prevent damage to the electrical system from rain. Also, avoid placing unit next
to a dirt road and do not install near or below exhaust fans that is ejecting dust
or caustic fumes. Special options are available for outside all weather exposure
or for exposure to flammable gases or liquids in the area.
Low Oil Switch: A safety device that shuts down the unit in the event of low oil
level. It is offered as an option on many models. It is not a substitute for routine
maintenance and the daily checking of your oil level. On units with a history of
poor maintenance, quite often the switch will become gummed up from sludge
and will not function. In this scenario , you have false security. The switch should
be tested when changing the oil.
Lubricants: ( Oil ) ACS offers a full line of compressor lubricants. It is vital that
the proper lubricant be used in your compressor. The wrong type lubricant can
severely damage your compressor.
• Automotive type oil should never be used in an air compressor due to its
incompatible formulation and lower heat range.
• Automotive type oil should never be used in an air compressor due to its
incompatible formulation and lower heat range.
• Automotive type oil should never be used in an air compressor due to its
incompatible formulation and lower heat range.
• Non detergent Automotive Oil should not be used.
• Synthetic Automotive Oil should not be used.
• If you can put it in your car engine you should not put it in a compressor.
• There are no exceptions.
Consult your owners manual for the proper lubricant. An ACS representative can
advise you if you are unsure of which oil to use. In most reciprocating type
compressors in use today. Our # 3 compressor oil is recommended. We also
offer synthetic compressor oils which are NOT the same as synthetic Automotive
oils. Rotary Screws, Rotary Vanes, Diesel Portables and other similar large
industrial units will require synthetic , or partial synthetic blends. Routine Service
and regularly scheduled oil changes are the life of your compressor. Failure to
change oil may result in lack of proper lubrication , clogged valves , clogged
intercoolers, carbon build ups, seizing and catastrophic failure. Oil level should
be checked daily.
Lubricator: An inline device that is designed to automatically inject a
pre-determined amount of lubricant into the air stream. Used to lubricate air tools,
air motors etc…
See Air Tool Oil.
Magnetic Starters: A magnetic starter is a relay device that connects the power
source to the motor. It is an electrical switch that is activated by an internal
electrical magnetic coil. The coil pulls in a set of heavy duty contacts to connect
power to the motor. The coil may be wired in series with the pressure switch, oil
safety switch, limit switch and overload among other options. In most cases the
Pressure Switch and Overload are present. If any of the switches in series with
the coil circuit are opened the coil releases the contacts and the motor stops. In
Units from 3HP(184 frame) Single phase and larger, and all Three Phase
motors. A Magnetic Starter is required. Trying to run power to a large motor from
only a pressure switch usually will result in damage to the switch and the motor.
ACS offers a full line of Magnetic Starters with Overloads. When ordering;
Provide Horse Power, Line Voltage, and Phase. In some cases, The Coil
Voltage may be different from the line voltage to the motor. Your Electrician
would need to open up the Starter box and verify the coil voltage markings.
A qualified Electrician should perform this repair and inspection.
*When ordering a Compressor unit from ACS. You can order the magnetic starter
mounted and wired for simplicity of installation , or loose for mounting on a
nearby wall.
Motors: Electrical Motors ACS offers a full line of compressor replacement
motors.
When replacing a motor you will need to look on the old motor tag and get the
following info:
• Voltage
• Frame(FR) size.
• RPM
• Shaft Diameter
• Phase ( PH )
Motor failure can be caused by ; Wear and tear, Bearing Failure, Abrasive Grit
from sand or other debris falling into motor, Chemical Exposure, Water,
Lightning, Overloading, Oversized Pulley, Seizing Pump or Air End, Bad
Capacitors, Undersize Wiring, Short Cycling from an improperly set pressure
switch, Low Voltage, Over Sized Breakers, Oversized Overload settings or
Heaters in the Magnetic Starter, Poor, Loose or Burnt Wiring Connections.
Special Motors are available for Wet Locations, Hazardous Exposure such as
gasoline vapors etc…
Normally , Most Compressors are equipped with the standard O.D.P. Open Drip
Proof motors. These motors require a roof covering to protect from weather
exposure and should be located in an area away from Sand blasting or similar
activities.
NEMA 1:An Electrical Enclosure suitable for indoor use. This is the standard for
most units. See: NEMA 4. NEMA 7,8,9
NEMA 4:An Electrical Enclosure suitable for outdoor weather. This option is
available upon request. See: NEMA 1, NEMA 7,8,9
NEMA 7,8,9 :Any of a series of special “Hazardous Exposure” Electrical
Enclosures. Used in the presence of Flammable gases or vapors. Available upon
request. See: NEMA 1, NEMA 4.
OIL CONSUMPTION: Oil lubricated reciprocating compressors will pass a small
amount of oil down stream. This is normal.
Note-Running unloaded for extended periods (dual control) may significantly
increase oil consumption.
The figures below are as a guideline only. Average oil use is approximately “1
ounce per 100 hp running hours.
1 oz. per 20 hours runtime @ 5 HP
1 oz. per 10 hours runtime @ 10 HP
1 oz. Per 4 hours runtime @ 25 HP.
OIL: See Lubricants.
Oil Sight Glass: Usually a round glass window affixed to a crankcase or oil
vessel. Generally the oil level is considered normal if it appears halfway across
the sight window when the unit is at rest. ACS offers press in and screw in sight
glass replacements, as well as a 1/4” in line oil flow sight glass.
Oilless Compressor: Any compressor that is not lubricated by oil. The most
common is the Hand held and smaller domestic type compressor. These units
often use a teflon wobble piston with a rigid rod. This type of construction is
aimed at low cost and consequently result in relatively short life span.
The higher quality units will use a teflon multi ringed piston that includes a wrist
pin. There are large industrial oilless units available as well. Oilless applications
include light contractor uses such as nail and staple guns, Medical, Dental,
Instrument air etc…..Oilless may be a good idea for contractors where the unit
may be placed on a slope while in use or where failure to check the oil may be a
chronic problem. Oilless is not recommended for most industrial or commercial
applications. An ACS representative can provide details regarding special oilless
applications your plant or system may require.
Overloads: Overloads are generally part of the magnetic starter. They are
designed to open the coil circuit and stop the power to the motor in the event an
overload occurs from whatever the cause. For this reason. Your Magnetic Starter
should be properly sized to match the motor HP and Voltage. Another type of
Overload is found on many Single Phase motors. It may be a Manual Reset Type
with a Red Button on the back of the motor or it may be an internal Overload that
automatically resets after a cool down period. In any event. Overloads “tripping
out” are telling you that you have a problem brewing somewhere. It needs to be
diagnosed and corrected. Bypassing an Overload can burn out the motor
permanently. See Motors.
Pilot Valve: A type of pressure sensing device that is designed to monitor the
system pressure and sends an air signal to other idling and unloader devices in
the system when the preset pressure has been reached. Usually used on Gas or
Diesel Units and Dual Control systems. See All In One.
Piping: Air system piping can be assembled with Black Steel or Galvanized type
pipe. Schedule 40 is suitable for pressures in the 175 PSI range.
As an alternative, Copper may be used as an alternative.
PVC or CPVC pipe material is unsafe and should never be used.
When piping an air system, special considerations need to be made for pipe
capacity, vibration, drainage slope, water extraction , filtration etc…
An ACS Representative can assist you in laying out your pipe system.
Pressure Switches: An Electrical device that is designed to monitor and control
the tank storage pressure and to shut off the motor by means of opening a
control circuit. In smaller units , the Pressure Switch may be wired directly to the
motor. However, in larger units the pressure switch is wired to a control circuit.
Typically the coil in a magnetic starter. When installing a new compressor. The
installer must be sure not to connect power to the pressure switch on large units.
A qualified electrician should make repairs to any electrical component.
A pressure switch is not intended to be used as a line pressure regulator.
ACS offers a complete line of pressure switches.
When ordering, you need to know:
• If your pressure switch has an unloader port. Does it point up or down?
• What is the inlet pipe size ?
• Does it have a multi port inlet?
• The cut on and cut off pressure.
• Is the pressure switch wired direct to the motor?
• Is the pressure switch wired direct to the magnetic starter?
See Regulator.
PSI: Pounds Per Square Inch. “Pressure”. Used to describe the storage
pressure, operating pressure, regulated pressure, air tool pressure requirement
etc… Used in conjunction with CFM which is an expression of volume. When
comparing Pressures and CFM between units, be sure to use both CFM and PSI
at the same compared values. Example; 17 CFM @ 175 PSI. or 6 CFM @ 90
PSI. See CFM.
Reciprocating: The Compressor Pump contains one or more pistons that move
up and down in motion in much the same way as automotive engines. It utilizes
rods, crankshaft and valves. This type of pump is by far the most common
compressor. Generally used in industrial , automotive and hobby applications.
Refrigerated Dryer: The most commonly used dryer type. Moisture extraction is
accomplished by refrigerating the air stream and lowering the dew point.
Regenerative Dryer: A type of dryer that uses a moisture absorption media,
usually Activated Alumina.
Regulator: An inline device designed to reduce downstream air pressure to a
specific adjustable setting. Regulators should be used in your piping system to
stabilize the working pressure of your tools and equipment and to prevent air
waste as well as damage to tools and equipment. A regulator should not be
confused with a pressure switch. Pressure switch’s are designed for tank storage
pressure only and is not intended as a method for controlling output line
pressure. Tampering with a pressure switch to attempt to control line pressure
will result in short cycling and premature wear on the electrical system of your air
compressor unit.
Rotary Screw: A type of compressor that uses two mated helical screws that are
rotated to produce compression. This is the most common constant duty
,Industrial compressor in use today. Generally in Horse Power Ratings from 20
HP and upwards to 500 HP. Used in manufacturing, mining and a host of other
applications where there is a demand for constant air or 100 % Duty Cycle.
Rotary Vane: A type of compressor that uses vane type blades, rotating inside a
stator housing to produce compression. Generally designed for 100% duty
cycles. See also Rotary Screws.
Rubber Donuts: Rubber Sleeves. A flexible donut type seal used for piping
connections on many rotary screw units. ACS carries those hard to find coupler
donuts and compression rubber sleeves.
Sand Blasting: ACS offers a full line of industrial sand blasting equipment and
parts. We also carry a Utility model for hobby and farm use.
Accessories include; Gloves, Hoods, nozzles, blast hose etc….
Safety Valve: A type of valve that is designed to relieve excessive pressure to
atmosphere. Used to protect Air Tanks, Piping, Pumps etc…
When ordering you need to know;
• PSI setting of the old valve.
• Pipe size.
• CFM discharge rating.
Never plug off a safety valve. Don’t even think about it.
Scavenge Line Filter: An inline filter device found on the scavenge oil return line
on rotary screw compressors. A clogged scavenge filter will cause oil to build up
in the Separator Tank and will result in oil passing down stream in the air system.
Single Phase: Electrical Power supply AC Voltage. Two hot legs and a ground.
This is the power virtually every home or business will have. Described as 115 or
230 volts.
Single stage: A compression action that involves one compression stroke or
cycle. Usually lower pressure units ranging 100 to 125 PSI.
Solenoid Valve: Electric Valves. These valves are used as control devices in a
wide range of air system applications. ACS offers electrically operated valves
ranging from 1/4” to 1-1/2”. In 2way and 3way configurations.
Stem Valve: Air Stem. A valve stem similar to those used on an automobile tire.
Used in air tanks, test ports and as a means of draining water traps.
Tank: ACS offers a full line of replacement tanks ranging in size from 8 gallon up
to 240 gallon. Special sizes are available upon request. Our 200 PSI rated tanks
are A.S.M.E. listed. Tanks are designed with top plates for mounting the pump
and motor. We also offer vertical remote storage tanks .(no top plate).
Tank Accessories include; Vibration Pads, Gauges, ball valves, safety valves etc.
Three Phase: Electrical Power supply AC Voltage. Three hot legs. This is the
preferred power source for Commercial and Industrial applications. Described as
208, 230 or 460 volt systems. See Single Phase.
Toilet Paper Filter: An inline filter device that uses a toilet paper type element to
remove water, oil and debris from the air stream. An economical approach.This
device is very popular with persons who occasionally need very clean air, such
as auto painting, but who cannot justify a more complete air treatment system.
ACS offers this filter in 1/4” and 1/2 “ pipe size’s.
Two Stage: Or Multi Stage. A compression action that involves compression and
recompression two or more times to achieve higher pressures.
The majority of Reciprocating Pumps used in automotive or light industrial are
two stage type pumps averaging 175 PSI. If you attempt to force a single stage
pump to produce higher pressures it may damage the pump or cause premature
valve failure. Most automotive applications should use a two stage pump.
Unloader: A term that refers to one of several methods of unloading the head
pressure from the pump head or air end at the completion of a pumping cycle.
Unloading is required in order to allow the pump or air end to start up with out a
load from the stored tank or system air pressure. This function is made possible
by venting the trapped or confined pressure between the pump or air end and
the check valve. See Check Valve.
Unloader: Pressure Switch. A small valve mounted on a pressure switch that is
triggered to open by the mechanical action of the pressure switch. When the
switch shuts the unit off it opens the unloader valve. This valve provides a means
of escape for the head pressure between the head of the pump and the check
valve to the tank storage pressure.
Unloader: Centrifugal or Positive. This unloading system is mounted on the
end of the crankshaft on Pumps. As the pump stops. A set of flyweights retract
and mechanically extend a pin to trigger a mounted unloader valve to vent the
head pressure from the pump . This allows the pump to start up on the next cycle
without a load. The advantage of the Centrifugal system is that in the event of a
power failure during a run cycle, the pump will be unloaded. If the pump relies
only on a pressure switch type unloader. The pressure switch may not unload the
pump if the power was lost during a pump cycle. When power comes back on,
the motor may trip the breaker or overload and may not be able to start at all.
Unloader: Head Unloading, Dual Control. This system is used on units that
allow the motor or engine to keep running but allow the pump to idle and not
produce compressed air even though it is rotating. This is accomplished by
means of a Pilot Valve and Head Unloaders. Head Unloaders are air actuated
plungers that depress the spring loaded valves into the open position thereby
disabling the pumping action in pumps.
On Rotary Screws the unloading is accomplished by closing off the air intake
throat. This system may be modulated in Rotary screws.
Unloader: Solenoid. This is a electrical valve that is usually normally open at
rest. When the magnetic starter activates, it energizes the solenoid and closes
the valve. When the starter shuts down the valve is released and the head
pressure in unloaded.
Valve Tools: Most popular Pumps use cartridge type valves or valves that are
assembled into the head with retainers. These valves generally require a special
tool to remove the hold downs or retainers. ACS offers a full line of valve tools for
Kellogg, Leroi, Wayne, Quincy and Saylor Beall.
Vacuum Pump: A type of pump that draws a suction rather than compression.
Used in Dental and Medical applications as well as specific industrial uses.
Vibration Pads: A rubber pad that is intended to support the leg of a tank .
Allows for vibration and helps reduce stress cracks on the tank.