摘要 |
A diaphragm pump comprising a pumping chamber (10) is operated by a continuous flow of pressure gas to a driving chamber (12) separated from the pumping chamber by a flexible diaphragm (8 or 52). Deflection of the diaphragm by the gas pressure drives liquid out of the pumping chamber. The driving chamber has a normally closed outlet valve (30 or 54) connected to the diaphragm through a flexible or lost-motion connection (34, 36 or 56) so that the valve is opened after a certain deflection of the diaphragm. The driving chamber pressure is thereby released and allows the diaphragm to return, drawing further liquid into the pumping chamber. The return movement of the diaphragm also allows the valve to reclose and the cycle is repeated while the supply of pressure gas to the driving chamber is maintained. |