Emerson Damcos, Service Manual

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Damcos LPU: Operating LPU-S 2 Service Manual
February 2017 SM 8000-100-01 Ed 04
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Operating LPU-S 2
Hydraulic Diagram LPU-S
To open valve
To move the valve towards open, the motor (3) is activated.
The oil is led from tank through the pump and through the non-return valve (15), directly to the
actuator B port. To prevent the oil from flowing back to tank, the solenoid valve (14) must be ener-
gized. When the valve is fully open, the pressure rises to 150 bar which causes the pump safety valve
(5) to open and the oil flows back to tank. The motor is de-energized.
The actuator is now hydraulically locked in position by the solenoid valve.
Safety/Actuator relief valve
In case of a major increase of temperature, the pressure may rise. This will not cause any problems
because of the safety valve (6) which will open at approximately 225 bar.
To stop valve in intermediate position
The valve can be stopped (and hydraulically locked) in any intermediate position simply by de-ener-
gizing the motor.
If the pressure drops while valve is fully open - due to a minor leakage in the solenoid valve or due to
temperature variations -, the pressure switch (12) will detect this. The motor may then be activated
1. Tank for hydraulic oil
2. Suction filter
3. Electrical motor
4. Pressure controlled flow adjustment
5. Pump safety valve
6. Actuator relief valve
7. Quick connection for hand pump suction
8. Fail safe actuator, single-acting
9. Quick connection for hand pump,
opening w/filter
10. Shuttle valve for hand pump, opening
11. Throttle for closing speed adjustment
12. Pressure switch
13. Pressure filter
14. Solenoid valve
15. Non-return valve
16. Opening speed adjustment
17. Variable displacement pump