GB612578A - Improvements in or relating to the control of end clearances of rotors - Google Patents

Abstract

612,578. Rotary pumps. KEELAVITE CO., Ltd., and CHITTENDEN, G. E. May 28, 1946, No. 16185. [Class 110 (ii)] Axial clearances between the faces of a rotor and its containing casing walls are controlled by pressure fluid which increases the force acting on a rotor face or a piston on the shaft when that face moves towards its adjacent casing wall. The rotor may form part of a rotary engine, pump, or meter, or a rotary valve, and the rotor and casing faces need not be flat but conical, convex or concave. Fig. 1 shows a pump with gears D, D<1> which are formed integrally with bosses D<2> so that the circumferential surfaces of these bosses, and the bores in which they lie, constitute sealing areas between the working chamber of the pump and further bores around bearings E<2>. During operation, the pump delivers liquid under pressure from the delivery chamber C through the clearances between the end faces of the gears to ports H, J, K, L leading to chambers G, G<1>, G<2>, G<3>, which are substantially closed though a small continuous leakage can take place through clearances between the ports F and E<3>. If gear D tends to move to the left, Fig. 1, thus reducing the clearance between its left-hand face and the adjacent face of the casing A<1>, the flow of liquid under pressure to the port H, from delivery chamber C, will be reduced, this reducing the pressure in the chamber G. The increase in flow of liquid through port J, to the chamber G<1> builds up pressure therein and tends to force the gear D back to the right. End recesses A' communicate with a relief chamber A<8> through a bore E<4> and passages A<9>, A<10>. In a modification, Fig. 5, the gears are formed integrally with bosses O<2>, providing circumferential seals with casing parts A, A<1>, and are secured to shafts O<3>, supported in bearings P, carrying pistons P<1> to provide pressure chambers Q, Q<1>, Q<2>, Q<3> to which ports J, H, K, L lead. When gear O moves to the left, extra liquid flows through the port J, less through H, so that pressure builds-up in chamber Q. This causes piston P<1> to move to the right and carry with it, the gear O. In a further modification, liquid is supplied to the chambers Q, Q<1>, Q<2>, Q<3> through metering orifices from a source of high pressure. The liquid escapes continuously through passages at rates which vary with the end clearances between the gears and the casing walls.