Emerson Damcos, Service Manual

Page: 113 / 144

Damcos LPU: LPU Technical Data Service Manual
February 2017 SM 8000-100-01 Ed 04
113
Technical Data
Opening/Closing
The LPU is fitted with a variable hydraulic pump enabling you to reduce the flow and thus the actua-
tor speed.
The pump flow and consequently the required motor power is automatically reduced whenever the
pump pressure exceeds a certain point. This does not influence the operating time of the valve
essentially, as the valve only requires high torque in the end positions. See examples of valve opera-
tion.
Valve Operation
Example of valve operation.
Valve is fully closed Valve is fully Open
Pressure will be built up until necessary break
away torque is obtained (98 bar). Pressure will be built up until necessary running
torque is obtained. (25 bar).
Valve begins to open and only running torque is
required from the LPU, pressure is reduced to
25 bar. Valve begins to touch the valve disc and more
pressure/torque is required, LPU starts building
up pressure to the reset torque. (67 bar)
Pressure is 25 bar during running of the valve. Pressure builds up to 67 bar and valve starts
end closing.
Valve reaches full open, actuator reaches end
position and pressure will start building up. LPU reaches max. pressure 150 bar, safety valve
releases flow to tank.
LPU reaches max. pressure 150 bar, safety valve
releases flow to tank. Valve is completely closed.
The extra time is passed and the motor/- pump
stops. The extra time is passed and the motor/pump
stops.
Valve is locked in position by a double pilot
operated non-return valve. Valve is locked in position by a double pilot
operated non-return valve.