Chicago Pneumatic CPS 750, Instruction Manual, Page: 18 / 94

CPS 750
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CPS
2 Leading particulars
2.1 General description
The CPS 750 is a silenced, single-stage, oil-injected screw compressor, built for a nominal effective
working pressure of 7.0 bar (102 psi).
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Engine
The compressor is driven by a liquid-cooled diesel engine.
The engine’s power is transmitted to the compressor element through a heavy-duty coupling.
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Compressor
The compressor casing houses two screw-type rotors, mounted on ball and roller bearings. The male
rotor, driven by the engine, drives the female rotor. The compressor delivers pulsation-free air.
Injected oil is used for sealing, cooling and lubricating purposes.
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Compressor oil system
The oil is boosted by air pressure. The system has no oil pump.
The oil is removed from the air, in the air/oil vessel at first by centrifugal force, secondly through the oil
separator element.
The vessel is provided with an oil level indicator.
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Regulation
The compressor is provided with a continuous regulating system and a blow-off valve which is
integrated in the unloader assembly. The valve is closed during operation by air receiver pressure and
opens by air receiver pressure via the compressor element when the compressor is stopped.
When the air consumption increases, the air receiver pressure will decrease and vice versa.
This receiver pressure variation is sensed by the regulating valve which, by means of control air to the
unloader and an electronic engine speed regulator, matches the air output to the air consumption. The
air receiver pressure is maintained between the pre-selected working pressure and the corresponding
unloading pressure.
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Cooling system
The engine is provided with a liquid-cooler and intercooler and the compressor is provided with an oil
cooler. (For available options see chapter
7 Available options .)
The cooling air is generated by a fan, driven by the engine.
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Safety devices
A thermal shut-down sensor protects the compressor against overheating. The air receiver is provided
with a safety valve.
The engine is equipped with low oil pressure and high coolant temperature shut-down sensors.
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Frame and axles
The compressor/engine unit is supported by rubber buffers in the frame.
The standard compressor has an adjustable or fixed towbar with brakes.
The braking system consists of an integrated parking brake and overrunbrake. When driving
backwards the overrunbrake is not engaged automatically. (For available options see chapter
7 Available options .)