The operation of a manual oil pump can be divided into four stages:
First, the preparation stage, ensuring the pump is correctly connected to the oil source and storage container;
Second, the suction stage, where the piston is lifted by the handle to create negative pressure to draw in oil;
Then, the discharge stage, where the piston is pressed down to expel the oil;
Finally, the circulation stage, repeating the above actions to continuously pump oil. Each stage relies on the precise coordination of valves; any valve malfunction will cause the pump to fail.
