GB1140268A - Improvements in or relating to rotary fluid pumps - Google Patents

Abstract

1,140,268. Rotary fluid-pumps. M. TUROLLA. June 30, 1966 [July 1, 1965 (2); Aug. 9, 1965], No.29427/66. Heading F1F. In a pressure-loaded rotary fluid-pump of the externally-meshing gear type, a wear-plate or cheek-plate 6 for the pumping gears 4, 5 is clamped between a central portion 3 of a housing or casing and an end cover 2 therefor, the flexibility of the portion of said plate abutting the gears being increased by an annular groove 15 in the face of the plate that is remote from the gears, the profile of which groove, Fig. 2 (not shown), is substantially similar to that of the pumping gears. The aforesaid portion of the plate 6 is pressed against the adjacent side faces of the gears by the pressure of fluid entering said groove and a shallow recess or depression 16 contiguous thereto from the high-pressure side of the gears, the profile of said recess being substantially that of a figure-of-eight. Fluid on the highpressure side of the gears has access to the groove 15 and the recess 16 through a cavity 17 and an axial bore 18 in the wear-plate. The groove 15 and recess 16 are sealed by rings 13, 14 that are lodged in the end cover 2. A spindle 204 attached to the gear 4 is coupled to a driving shaft 20 that is supported by a ball bearing 25 in a portion 21 of the housing, there being splines formed on the wall of a bore 26 in said shaft that engage with splines formed on a sleeve 27 attached to the spindle 204. In a modification, Figs. 5 to 8 (not shown), the groove 15 has a profile substantially similar to that of a figure-of-three, the central portion of the groove on the high-pressure side of the gears being replaced by a curvilinear slot or slit (35), which gives fluid across to the recess 16. In the embodiment shown in Fig. 1, the depth of the groove 15 varies and is greatest on the high-pressure side of the gears, Figs.3 and 4 (not shown), so that the flexibility of the portion of the plate 6 abutting the gears varies accordingly and the pressure exerted on the gears by said plate matches the pressure gradient of fluid lodged in the gear-tooth spaces. A similar provision is made in the pump according to Figs. 5 to 8 and the required variation in the flexibility of the plate 6 is facilitated by the slot (35) therein, Fig. 10 (not shown). It is indicated that the pump may be provided with two wear-plates with the gears situated therebetween, each plate being provided with a groove 15 and a slot (35).