Abstract: The present invention relates to a pump, which comprises a pump body, a pair of check rings and a pneumatic control valve. When the pneumatic control valve is operated, a main shaft in the pump body is enabled to reciprocally move in a shaft hole, thereby enabling two diaphragms to be stretched and compressed at the same time for performing the compressing and the sucking stroke for the liquid; when subject to the hydraulic pressure, an arc-shaped convex ring of each of the check rings is deformed, and a contract ring is contracted for enclosing the main shaft thereby forming a liquid checking effect; when each of the check rings is not subject to the hydraulic pressure or the air pressure, the arc-shaped convex ring is not deformed thereby forming a slit between the contract ring and the main shaft.

Abstract: The present invention relates to a pump, which comprises a pump body, a pair of check rings and a pneumatic control valve. When the pneumatic control valve is operated, a main shaft in the pump body is enabled to reciprocally move in a shaft hole, thereby enabling two diaphragms to be stretched and compressed at the same time for performing the compressing and the sucking stroke for the liquid; when subject to the hydraulic pressure, an arc-shaped convex ring of each of the check rings is deformed, and a contract ring is contracted for enclosing the main shaft thereby forming a liquid checking effect; when each of the check rings is not subject to the hydraulic pressure or the air pressure, the arc-shaped convex ring is not deformed thereby forming a slit between the contract ring and the main shaft.

Abstract: The present invention relates to a separation type pneumatic dual partition membrane pump, which comprises a pump body and an external pneumatic control valve which is separately installed. Through the operation of the external pneumatic control valve, the main shaft of the pump body and the valve rod of the external pneumatic control valve are reciprocally moved, and the two partition membranes respectively generate stretch and compress motions for changing the volume of each liquid room in the pump body so as to perform the pump stroke and the liquid suction stroke to the liquid.