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interstage pressure (D) increases, transferring the shuttle valve (4) and pressurizing the
operating chamber (B), keeping the capacity control valve open.
FIGURE 5 - COMPRESSOR LOADED
When the compressor is running, compressor outlet air pressure is monitored by a
pressure sensor on the air piping. When the compressor outlet air pressure reaches the
upper limit of the desired operating range, the 4-way solenoid valve is de-energized,
venting the operating chamber (B) to atmosphere and pressurizing the spring chamber
(A). The inlet valve (1) closes and bleed-off valve (2) opens. As the inlet valve closes a
vacuum develops at the 1st stage inlet which keeps the CCV in the unloaded position.
When unloaded a slight amount of air is drawn through orifices in the inlet valve to cool
the compressor during unloaded operation. The air flow (F) is vented to atmosphere out
of the bleed-off silencer. The check valve prevents plant compressed air system air
pressure from pressurizing the compressor.