Patent GB-860556-A (GB)
Title: Improvements in rotary motion pumps or motors
IPC: F01C1/344
Filed: 1959-11-20
Abstract: 860,556. Rotary pumps or motors. TROJAN CORPORATION. Nov. 20, 1959 [Nov. 20, 1958], No. 39493/59. Class 110 (2). In a rotary pump or fluid-pressure motor of the kind wherein vanes arranged radially in a circumferential groove in a rotary body act piston-wise relatively to a stationary block or blocks in the groove and are cammed transversely out of the groove and back again to clear the block, the angle of travel over wnich camming is effected at each side of the block is increased to exceed the angular extent of the respective part at that side of the block, the camming angle being at least 180 degrees/B 1 b (1--)--- t, where B is the number of n 2 blocks, n is the number of vanes per block, t is the angular thickness of each vane in degrees and b is the angular thickness of the, or each, block in degrees. The blocks may be on the rotary member and the vanes may be displaced radially for clearing the blocks, but as shown in Fig. 4, blocks 57, 57a, 57b, 57c are carried by a stationary bushing 40 in which rotates a drum 42 having grooves 55, 55a, 55b, 55c into which the blocks project. The capacity of the machine is increased by increasing the number of vanes per block, but in Fig. 4, two blocks, that is, an upper and lower block, and light vanes 66 are provided in each groove, the vanes being formed between block-clearing notches 70, 70a, 70b, 70c on a slider 68 operated by stationary cam faces 76, 77. To prevent binding of the slider due to unbalanced fluid pressures on its faces, passages 120, 122 join recesses 121, 123 beneath the sliders to the high and low pressure ports which are, at the moment, above the sliders; and leak passages 441, 451 equalize fluid pressures at both ends of the drum. The sliders 68 may be kept clear of the bottoms of the slots in which they work, by supporting them on a line of ball-bearings which run in complementary half-grooves in the side walls of the sliders and their guiding slots. Also, to prevent the cams 76, 77 from bending the ends of the sliders 68, the ends are not allowed to protrude from the slots, the cams 76 being formed with annular parts which project into annular grooves which intersect the guide slots for the sliders 68. The cams 76, 77 are axially adjustable by screws 81. The inlet and exhaust manifolds 85, 86 are in communication with ports 89, 90 and 91, 92 respectively, the inlet and exhaust ports 89, 91 and 90, 92 being arranged on each side of upper and lower blocks 57. The blocks are positioned by pins 58 which project into slots in the blocks which are thus able to adjust themselves axially of the drum. The fluidpressure differentials on the sides of the blocks tend to cant the blocks in the grooves 55, and this is prevented by wing-like projections 150, 151 which are tapered on one side and are curved to fit into the grooves. To balance on both sides, of the wings, fluid-pressures caused by trapping of fluid between a vane and a block, a clearance space 154 is left to receive counteracting fluid, passages 158 through the wings and a passage 159 through the block, being provided if necessary. The cam surfaces are designed to allow the transversely moving vanes 66 to follow closely the tapering contours of the wings, which reduces the time during which the vanes are fully displaced from their working positions. Trapping of fluid between the sides of the notches in the transversely moving sliders 68 and the blocks, is prevented by allowing sufficient clearances in the notches to allow the fluid to pass from one side of the notch to the other side. The sealing surfaces between the stationary bush 40 and an outer casing 41 are slightly tapered and are tightened by set screws 41a, and the relatively moving contacting surfaces of the bush 40 and the drum 42 also are slightly tapered and are adjusted axially.