1. Charging: when the oil pump starts to work, the oil is inhaled into high, low pressure one-way suction valve by the plunger and pushed into operating cylinder via high, low pressure one-way outlet valve. When the pressure increases to 1.5 MPa, the low pressure relief valve opens and the low pressure oil spills back to the reservoir.
2. Boosting: the high pressure plunger continues to work after that and the pressure increases gradually. When the pressure exceeds the rated pressure 63 MPa, the high pressure valve will open and the high pressure oil will be back to the reservoir from the high pressure relief valve, so the pressure will be maintained at 63 MPa. The high-pressure valve is the safety valve.
3. Working: during the working process, the energy will decrease as the working cylinder works, so the handle should be pumped to keep the required working pressure until the work ends.
4. Discharge: when the oil pump work ends, the pressure should be reduced to zero. Open the unloading valve and the liquid oil flow back to the reservior. The discharge work is finished.
Charging, boosting and working are indivisible, which are driven by pumping the handle.