With one or several periodic changes in the sealed cavity, ---- positive displacement pump.
It has a port device to separate the oil suction and pressure chambers (Port refers to the conversion of oil suction and output)
The volume of oil inhaled or discharged by the pump per revolution depends on the change of sealing volume
The absolute pressure of the liquid in the tank is greater than or equal to atmospheric pressure.
The essence of oil absorption is the action of atmospheric pressure
The discharge pressure depends on the total resistance
The oil drain time gap causes leakage, and the leakage causes volume loss