GB697822A - Improved diaphragm pump - Google Patents

Abstract

697,822. Diaphragm pumps. NAAMLOOZE VENNOOTSCHAP DE BATAAFSCHE PETROLEUM NAATSCHAPPIJ. July 23, 1951 [July 21, 1950], No. 17405/51. Class 102 (i) [Also in Group XXIX] A pump, particularly suitable for muddy liquids, comprises a pair of chambers, 1, 1<SP>1</SP>, divided by diaphragms 2, 2', the lower chambers of which form the pumping chambers and are connected to suction and delivery valves 6, 6', 8, 8'. The upper chambers are alternately supplied with operating liquid or connected to suction for withdrawing the liquid under the control of the change-over valve 15, and it is arranged that the suction stroke is performed more quickly than the forcing stroke, e.g., by arranging that the forcing pump 13 has a smaller capacity than the suction pump 12. The change-over valve is arranged that during the operation of changing the connections to the diaphragm chambers, the rate of increase in area of one set of passages is equal to the rate of decrease in area of the other set so that the combined delivery of the two diaphragms remains constant. The change-over valve is actuated by a piston 22, the supply and exhaust of pressure fluid to which is controlled by a slide valve 34 for each diaphragm and actuated by stops 38, 39 on a rod 37 connected to the diaphragm. The arrangement is such that the diaphragm that executes its suction stroke adjusts the appropriate valve 34, but the piston 22 is not operated until the other valve 34 is adjusted by the diaphragm reaching the end of its forcing stroke. The diaphragms may carry valves that close the liquid passages when the diaphragms are at the ends of their strokes. Indicators 45, 45' may be provided that respond to electrical conductivity or di-electric constant of the liquid passing in pipes 18, 18' to detect leakage of the muddy liquid pumped into the operating liquid. The pumps may be supplied with muddy liquid under pressure.