13-10-615 Page 30
Inlet Valve
(Figure 1-4, page 2, and Figure 4-4, page 30) - The Inlet valve restricts the inlet to control
delivery and closes to unload the compressor. At shutdown, the inlet valve closes to prevent the back
flow of air.
The inlet valve position is controlled by air pressure in its piston cylinder, which is controlled by the
“AutoSentry” Controller through solenoid valves IVC and IVO. As pressure to the piston is increased, the
valve closes to restrict air flow and compressor delivery.
Figure 4-4 – INLET VALVE
Solenoid Valves IVC and IVO
- These valves control position of the inlet valve in response to signals
from the “AutoSentry”. With both valves de-energized, the normally open IVC valve allows control
pressure to the inlet piston to close the valve. If IVC only is energized, the inlet valve is held in its current
position. If both valves are energized, control pressure is relieved from the inlet piston to allow the valve
to open.
Pressure Regulator
- The pressure regulator is used to supply a constant and low control pressure to
prevent damage to the inlet valve from “slamming.” The regulator should be set for 25-30 psig.
Shuttle Valve
(Figure 4-5) - Also known as a double check valve, the shuttle valve is a device which will
take two (2) supply signals and allow the one with the highest pressure to pass through. The shuttle
valve is used to provide control air pressure from either the reservoir or plant air system, as required
during different operating conditions.
203EAU797-A
(Ref. Drawing)
