| 摘要 |
Diaphragm pumps are used for pumping liquids and comprise rods passing through a housing for effecting diaphragm return movement. This invention provides a novel diaphragm pump which avoids the use of those rods. The novel pump has an air chamber (26) and a pumping chamber (30) separated by a composite diaphragm (16, 18). Feeding compressed air to the air chamber (26) moves the diaphragm to effect a pumping stroke. The return stroke of the diaphragm is achieved by exhausting the air chamber (26) while feeding compressed air to a further air chamber formed between first (16) and second (18) membranes of the composite diaphragm. The area difference between the membranes is sufficient to make the composite membrane (16, 18) self-erecting, to draw fluid into the pumping chamber (30) ready for the next pumping stroke of the diaphragm. |
