摘要 |
A double diaphragm pump comprises a center body 10 and two end-caps 11, 12, the outer peripheries of two diaphragms 20, 21 being clamped between the center body and the two end-caps respectively. The diaphragms are interconnected by a hollow push-rod 26 slidably and sealingly mounted in a bush 17 in the center body. A shaft 30 extends centrally through the push-rod, diaphragm and end-cap and has a radial flange at one end and a nut engaged on a screw-thread at its other end whereby the end-caps, diaphragm and center body are clamped axially together. Air under pressure is supplied to the two axially outer chamber 23, 24 formed between the diaphragms and the end-caps under the control of a change-over spool valve 45, change-over operation of which is initiated by the approach of the push-rod 26 to either end of its reciprocating movement.
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