High Pressure Connections; Pressure Control Valve - Hartridge HB378 Bedienungs- Und Wartungshandbuch

OPERATING & SERVICING MANUAL

4.3 High Pressure Connections

The high pressure connections are different to traditional HP pipe connections. The pipes have
coned and threaded ends and the high pressure seal is made by the pipe nut acting on the threaded
collar and forcing the coned end of the pipe onto the female conical seat.
NOTE When fitting these connections, ensure that the collar is backed off sufficiently to allow
the cone face to seal, rather than the connection bottoming out at the edge of the collar.
NOTE The recommended tightening torque for the pipe nuts is 34-38Nm (do not exceed 50Nm).
For pump flow testing, the high pressure circuit should be as shown in Figure 4.1.
1. Connect the pump to the dump valve using flexible HP hose A079B111. This pipe is fitted with an
M12 pipe nut. If the pump has an M14 connection, then adaptor A069B256 and seal A069B254
will be required – see Figure 4.2.
2. Connect the dump valve to the PCV using pipe A079B114.
Figure 4.1: Pump Flow Testing – Test Oil Circuit

4.4 Pressure Control Valve

The PCV applies a back pressure to the pump to enable flow testing at various pressures. The
required pressure is actually produced by changing the orifice size in the valve (for a given flow, a
larger orifice will generate a smaller pressure, and a smaller orifice larger pressure).
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Figure 4.2: M14 to M12 Adaptor Fitting
HARTRIDGE LIMITED
HL024, Issue 7 (AT2672)