The seat body is composed of a seat body and a hand pump which is buckled on the seat body. The seat body is provided with an oil inlet passage, an oil outlet passage and a filter tank channel. A compression spring is arranged between the seat body and the hand pump. A one-way valve is arranged on the oil inlet passage, a one-way valve is arranged on the oil outlet passage, and a filter tank oil channel is connected at the lower side of the middle part of the oil inlet passage,
When it works, when the hand pump of the manual pump is lifted, the check valve is closed, and the one-way inlet valve is opened. The fuel in the fuel tank directly enters the filter through the oil inlet channel on the filter seat and the filter tank channel, and enters the filter seat through the open oil inlet check valve after being filtered by the filter element,
When the hand pump of the manual pump is pressed down, the inlet check valve is closed and the check valve is opened. The fuel in the filter seat is pressed to the oil outlet passage through the open one-way valve,
Press the hand pump repeatedly, the air in the filter will be squeezed out of the filter tank by the fuel, and the clean fuel filtered by the filter element will reach the oil outlet passage.