WIKA CPB5000HP - Handbuch (Seite 14)

Pressure Balance High-Pressure GB
CPB 5000 HP
WIKA Operating Instructions Pressure Balance High-Pressure Version 2.3 14
3.1.4 Venting the System .
After the clamping of the piston/cylinder system and the test specimen, air may be trapped in the
system again. The system may be vented before beginning with calibration using the following
procedure:
The piston/cylinder system and test specimen must be clamped, and the complete weight set must
be placed on the piston/cylinder system.
Close the low-pressure shut-off valve
Open the high-pressure shut-off valve
Generate a pressure of approximately 50 bar using the initial pressure pump
Close the high-pressure shut-off valve
Increase the pressure with the spindle pump until just below the final value of the value range of
the piston/cylinder system, or of the test specimen (the smaller pressure range is the decisive
factor).
Important: The piston/cylinder system must remain in its lower position for this
operation, i.e. not yet moving into equilibrium.
Carefully open the high-pressure shut-off valve, any trapped air will escape into the tank
Open the low-pressure shut-off valve
This procedure may need to be repeated several times in order to remove all trapped air.
Opening the high-pressure shut-off valve without first turning out the spindle pump in counter-
clockwise direction in order to relieve the system on initial pressure is permitted only with the venting
procedure described herein, since the piston is located in the lower position.
After generating initial pressure, the high-pressure shut-off valve must always
be closed before pressure is increased using the spindle pump. An integrated
safety overflow valve (adjusted to approximately 100 bar) additionally protects
the low-pressure circulation from any errors on the operator’s part.
The device is now ready to use.