Why does the gear pump hydraulic system enter the air,      Parker Gear Pump    analysis 9 points

1 The oil level of the fuel tank is lower than the oil standard, and the oil suction, oil filter or suction oil pipe is exposed on the oil surface. 2 The oil return pipe in the fuel tank is too close to the oil suction pipe, and there is no partition between the two (or the broken bubble net). The foam generated by the oil returning is not as heavy as the air is sucked into the pump.

2 The pipe joint exposed between the oil level and the inlet of the hydraulic pump is not well sealed or the pipe joint is loose due to vibration, or the pipe is cracked, and the air is sucked in.

3 Air is introduced due to damage to the oil seal of the pump shaft and damage to the seal between the pump body and the cover of the gear pump.

4 The oil suction pipe is too thin and too long. The oil suction filter is blocked by dirt or the capacity of the oil filter is designed to be too small to increase the oil absorption resistance.

5 The oil deteriorates and deteriorates. Due to the emulsification of the influent water, the foam breaking performance deteriorates. The bubbles are dispersed inside the oil layer or floated on the oil surface with the mesh bubbles, and the system is sucked into the system when the pump is working.

6 The hydraulic cylinder is not exhausted for exhausting.

7 The oil is mixed with volatile substances (such as gasoline, ethanol, benzene, etc.), which volatilize from the oil in the low pressure zone to form bubbles. On the return line without the back pressure valve, and sometimes the cylinder is under negative pressure.

8 hydraulic cylinder head cover is not well sealed, sometimes intake air, sometimes oil leakage.