Instruction Manual
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2.4.4
Continuous regulating system
The compressor is provided with a continuous regulating system and a blow-off valve (BOV) which is integrated in
the unloader assembly (UA). The valve is closed during operation by outlet pressure of the compressor element and
opens by air receiver pressure 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 (RV) which, by means of control air to the unloader assembly (UA),
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.
When starting the compressor, the throttle valve (TV) is kept closed via receiver pressure. The compressor element
(CEhp CElp) takes in air and pressure builds up in the receiver (AR). The throttle valve (TV) is closed. The air
output is controlled from maximum output (100%) to no output (0%) by:
1
Speed control of the engine between maximum load speed and unloading speed (the output of a screw
compressor is proportional to the rotating speed).
2
Air inlet throttling.
If the air consumption is equal to or exceeds the maximum air output, the engine speed is held at maximum load
speed and the throttle valve (TV) is fully open.
