GB1330610A - Metering pump - Google Patents

Abstract

1330610 Reciprocating pumps CHEMIE UND FILTER GmbH and V DULGER S DULGER A DULGER and R DULGER 6 June 1972 [15 June 1971] 26418/72 Heading F1A A pump, e.g. for feeding small amounts of phosphate into process water, comprises a pumping element 30 reciprocated through a liquid column by an actuating piston 20, an adjustable throttle 35 in the liquid column acting to control the speed of at least the discharge stroke of the pump. As shown, the throttle is by-passed on the suction stroke by a non-return valve 31. A second throttle 37 is responsive to the pressure drop across throttle 35. Pumping element 30 may be a diaphragm, as shown, a pistonactuated bellows, Fig.3 (not shown), or a piston. Actuating piston 20 is moved forwardly by a solenoid 12 and rearwardly by a spring 17, the solenoid stroke being adjustable by a stop 18, 19. The solenoid is controlled by a switch 58 responsive to the pressures in the actuating chambers 26, 29 detected by gauges 56, 60. Gauge 60 regulates the solenoid power to maintain a constant actuating pressure. A make-up valve 34 supplies liquid to the column from reservoir 25. Vent values 32, 33 are provided. Two pumps, Fig.1 (not shown) may be arranged to operate alternately with switch 58 energizing one pump as the other reaches the end of its discharge stroke. Value 31 alternatively may be electromagnetically operated in response to the end of the discharge stroke. The solenoid stroke may be adjusted electronically.