| 摘要 |
A diaphragm pump comprises a body defining a chamber in which a diaphragm is arranged to divide the chamber into a drive chamber and a pump chamber. The pump chamber has an inlet and an outlet for fluid to be pumped, each of the inlet and outlet being provided with a one-way valve. The drive chamber has an inlet for driving fluid and the inlet is provided with a valve which is open under normal operating conditions of the pump. The valve is arranged so that, if a high pressure persists in the pump chamber when the pressure in the drive chamber is relieved causing the diaphragm to expand, the diaphragm will contact the movable valve member of the valve to move it to a position closing the inlet opening so that the drive chamber is isolated from the drive fluid pressure variations while the abnormal pressure subsists in the pump chamber.
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