Section 2. Air Compressors; How It Works - Waterous 80-P Operation Manual

SECTION 2. AIR COMPRESSORS

A. How It Works
The air compressor used in this application is an oil flooded rotary screw type. Rotary screw air
compressors are very common in industrial applications. This type of compressor injects oil into itself,
where it lubricates, seals, cools, and silences the compressor. The oil is then entrained into the air
discharge from the compressor. This air/oil mixture is discharged into a sump tank where most of the
oil separates from the air. The oil is then sent via hydraulic hose to a combination cooler / filter unit. It is
cooled to remove compression and friction heat, filtered, and sent to the oil injection port on the
compressor. The cycle is then repeated.
The oil mist that remains in the air stream is recovered by an air/oil separator system. This system
recovers the oil mist in a spin-on cartridge that has a siphon tube that picks-up the recovered oil for
return to the air compressor.
The compressor's air output is controlled by a modulating inlet valve. The inlet valve is opened and
closed by the Auto-Sync pressure control system.
The compressor cooling system circulates water from the fire pump through the compressor oil cooler
and back to the tank to remove heat from the compressor oil system. The compressor oil temperature
should not exceed 250° F. If this occurs, check the water supply; pump prime, restrictions in the cooling
water system and for low oil level in the sump.
The air compressor (air end) is driven via a transmission power take-off. It is important to ensure that
there is a water supply from the fire pump whenever the engine is running. Pump and/or compressor
damage may result from running the pump dry.
F-1031, Section 2416
Figure 2 CE 55 G
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