Function - WIKA CPB3800 Betriebsanleitung

4. Design and function
Masses are loaded directly onto the piston head for low pressure calibration points. A
coloured band indicates when the piston is floating.
For higher pressure points, an overhang is fitted directly to the piston head, and weights
located at the bottom of the overhang or located on top of it. A machined groove on the
main piston body indicates when the piston is floating.

4.5 Function

Operation of the pressure balance is controlled by the two valves A and B on the top
of the reservoir/high pressure cylinder block. When initially priming the system valves
A and B are opened to fill the system with oil from the reservoir. Valve B is then closed
with valve A left open and the screw pump operated to provide the lower test pressures.
To provide the higher pressures valve A is closed to seal off the test circuit from the low
pressure part of the screw pump and valve B is opened to allow the liquid in the low
pressure part of the screw pump to return to the reservoir as the pump is operated. This
ensures that the pump can be operated without having to put large forces on the screw
pump handwheel. To release the test pressure the screw pump is wound out and valve
A is opened.
WIKA operating instructions model CPB3800
Valve A
Hand pump
Reservoir
Valve B
GB
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