| 摘要 |
1,259,903. Centrifugal,reciprocating and rotary pumps. C. M. CHRISTIE. Dec.17, 1969, No.61520/69. Headings F1A, F1C and F1F. A liquid supply system (particularly a water supply system for a boat or caravan) comprises a supply tank or reservoir having an outlet pipe with a discharge end located at a level above that of the tank or reservoir, a manually operable valve device a tap 7 at or adjacent the discharge end, and an electric switch a micro-switch 15 actuable by a cam 12 by opening and closing movements of the valve device respectively to energize or de-energize the driving motor of a pump which generates the necessary pressure in the outlet pipe, energization taking place before the valve device has been moved sufficiently to establish fluid communication between the pump and the discharge end and de-energization taking place after communication has been broken. Preferably, the pump is of centrifugal type. Alternatively, the pump may have a relief valve to limit the output pressure or may be a self-priming pump having flexible blades which yield above a certain output pressure or a diaphragm pump having a compressible air chamber which limits the output pressure.
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