GB1040331A - Improvements in or relating to hydraulic actuators - Google Patents

Abstract

1,040,331. Reciprocating pumps. J. F. A. MEYER. March 28, 1963 [Feb. 7, 1962], No. 4633/62. Headings F1A, F1N and F1P. A pump, compressor or singlestroke motor diaphragm or piston is moved by the vapour pressure produced by passing an electric current through a liquid, e.g. water, in a chamber. In the embodiment of Fig. 1, diaphragm 2 is moved against a spring 29 by vapour pressure generated in chambers 7, 8, 9 and 10 acting through liquid contained in the system. The stroke is varied by selectively operating the chambers, vapour from chambers 8, 9 and 10 passing into chambers 5 and 6. The volumes of chambers 5, 6 and 7 are in the ratio 8:2:1 to give a stroke range of 10 steps. The electrode tips may be shaped such that when the liquid level falls to partially uncover them, the current flow is reduced to a level sufficient to maintain the volume of vapour constant, a time switch acting to cut off the current prior to the return stroke. During the return stroke under spring 29, the vapour condenses, cooling fins 18 being provided. In another embodiment a cooling jacket surrounds the vapour chamber and is filled with liquid, e.g. oil, during the return stroke and emptied during the working stroke. The electrode may be mounted on a bimetallic strip to compensate for pressure fluctuations. Compensation for liquid losses from the system or for variation in volume with temperature, is effected by a bellows either manually or automatically, e.g. by a sight-glass and set-screw, or a photo cell and cam. More than one electrode may be provided in the vaporizing chamber. Alternative shapes and arrangements of electrodes are described.