Pump Pressure Relief Valve Operation (Steering)

Pump Pressure Relief Valve Operation

= Fluid intake

A

B = Fluid discharge

1. Inlet port
2. Discharge port

A pressure relief valve is located in the centre of the flow control valve. If the pressure on the discharge side of the metering orifice reaches a predetermined level, a spring loaded ball in the centre of the valve will lift from its seat and allow pressurized fluid to recirculate within the pump.

The pressure relief valve will operate if the discharge from the pump is restricted, steering held at full lock. If the discharge from the pump is completely blocked, all fluid discharged will be recirculated through the pump.

As no fresh oil is drawn into the pump from the reservoir, the fluid temperature inside the pump will increase quickly. Consequentially, periods of operation of full lock should be kept to minimum to avoid overheating the pump and the fluid within it.

3. Metering orifice
4. Pressure relief valve