GB656970A - Improvements in or relating to hydraulic reciprocating pumps - Google Patents

Abstract

656,970. Reciprocating pumps. HOBSON, Ltd., H. M., SIMPSON, T., EDWARDS, T., and GREENLAND, L. S. Jan. 19,1949, No. 1498. '[Class 102(i)] [Also in Groups XXVI and XXIX] A variable delivery hydraulic pump has at least one pair of pump units discharging into a common outlet, each unit comprising a pump barrel disposed radially to a cam shaft and having inlet and delivery valves at its outer end; a cam mechanism on the cam shaft for reciprocating the pump plungers in the barrels and so shaped that the plungers of each pair of units produce a constant rate of flow through the outlet; a regulating member co-axial with the cam shaft and having rocker arms pivoted thereto on axes parallel with the shaft for imparting motion from the cam mechanism to the plungers; and means for rotating the regulating member for varying the effective length of the rocker arms and thus varying the stroke, the plungers being held at their outer positions when the regulating member is turned to zero delivery position in which the rocker arm pivots are aligned with the plunger axes. The pump which is intended for supplying liquid fuel to a gas turbine comprises four banks A, C, B, D, Fig. 4, each of four radial cylinders 66 arranged " in line " and containing spring- loaded plungers 80. The plungers in banks A, C are actuated by a cam 61 and those in banks B, D by a cam 62, both cams being integral with a shaft 60 splined to a drive shaft 65. The two cylinders A, B of each line of cylinders are connected through spring-loaded delivery valves 88 with the same delivery passage 87, Fig. 5, and the two cylinders C, D are connected together in a similar manner. The cams 61, 62 are disposed 180 degrees out of place and are so shaped that the delivery from the connected cylinders is constant. Between the cams and plungers rocker-arms 77 are interposed, these being.pivoted on axial pins 76 carried by a sleeve 67 surrounding the cams and having at their ends rollers 78 which extend through openings in the sleeve and are pressed into engagement with the cams by springs 79. The delivery of the pump is variable between maximum and zero by rotating the sleeve 67 through a manuallyoperated vane type servomoter (see Group XXIX), and thus varying the point of contact of the rocker arms and their respective plungers and hence the stroke thereof. Fuel is supplied to the cylinders through spring- loaded inlet valves 85 and axial passages 83 which communicate with a common inlet connection 19. A gear pump supplies fuel under pressure from a reservoir. Specification 632,261 is referred to.