GB1010132A - Improvements in rotary gear pumps - Google Patents

Abstract

1,010,132. Gear pumps. PARKER-HANNIFIN CORPORATION. Sept. 1, 1962, No. 33637/62. Heading F1F. A gear pump comprises a casing 10 (Fig. 1) having an end cap 11 and containing a generally cylindrical unitary gear subassembly 12 which includes pumping gears 24, 25 having integral bearing-stubs or journals 26 lodged in bushings 35 carried by end plates 30, 30a on either side of a centre plate, 31 the assembly being placed in casing 10 to effect engagement of a splined driving-shaft 22 with splines 28 in either of the pumping gears. Fluid entering the pump through an inlet 15 passes into assembly 12 through an opening 40 (Fig. 4) in end plate 30 and an opening 33 in centre plate 31 having a volute configuration (Fig. 8, not shown) to suppress cavitation in the fluid approachthe gears, opening 40 and an opening 40a in axial alignment therewith in end plate 30a being in communication with spaces 44a to effect cooling of the assembly. To facilitate entry of the fluid into the gear-tooth spaces, shallow recesses 45, 45a are provided in wear plates 32, 32a adjacent notches 43, 43a therein which are in register with openings 40, 40a, further recesses 48, 48a being provided in the wear plates to facilitate discharge of fluid from the gear-tooth spaces through bores 46, 46a 47, 49, 49a, 50 in plates 30, 30a 31 and thence to an outlet 16 through a ring 51 lodged in end cap 11. Pressure exerted on ring 51 by fluid passing therethrough effects axial loading of the assembly to minimise leakage of fluid between the side faces of the gears and the wear plates, the ring being sealed by an O-ring 55. Lubrication of journals 26 is provided by leakage of fluid through axially-extending grooves 37 in bushings 35 from annular grooves 27 in the gears to shallow bores 39, 39a which intersect openings 40, 40a. Grooves 27 in each gear communicate with one another through bores 74 (Fig. 6) in end plates 30, 30a and bores 58a, 59, 60a containing a clamping screw 57 to equalize pressures on either side of the gears and improve the lubrication of journals 26. Leakage fluid in a seal assembly 18 for shaft 22 escapes by flowing downwardly through one or other of a pair of passages 19, the uppermost passage being closed by a plug 20.