| 摘要 |
<p>A diaphragm valve for the water intake in irrigation systems or similar comprises a hollow body (1) having a port (1a) to connect a hydraulic or pneumatic system to the interior of the body of the valve and at least one ventilation opening through a side wall or walls of the body from the exterior to the interior of the valve. A diaphragm (7) is movably mounted within the interior of the body and normally closes the port. There is a bleed aperture through the diaphragm around the guide member (10) to a cavity (12) behind the diaphragm. When the pressure on the port side of the diaphragm falls below the external pressure, the diaphragm will move away from the port to open the port to fluid entering the interior of the body of the valve through the side wall(s) of the body of the valve, and the diaphragm will move to close the port when the pressure on the port side of the diaphragm is equalised whith the external pressure. Preferably the diaphragm comprises a thin flexible annula r skirt (7c) extending from the periphery of the diaphragm with the distal edge of the skirt retained in an annular recess (8) around the cavity behind the diaphragm to movably mount the diaphragm within the interior of the body of the valve so that the diaphragm moves by flexing and/or folding of the skirt.</p> |
