GB1233376A - - Google Patents

Abstract

1,233,376. Rotary pumps and motors. A. B. COLE. Feb.14, 1969, [Nov. 17, 1967], No.52414/67, Heading F1F. A rotary pump or motor of the kind in which an externally-toothed rotor is disposed within an internally-toothed annulus having one more tooth for meshing engagement with the latter in the same direction of rotation about relatively eccentric axes, wherein the annulus is housed with radial clearance in the pump or motor casing, is substantially constrained against orbital movement and is resiliently and/or fluid-pressure urged radially towards the rotor in a direction tending to reduce the relative eccentricity of the rotational axes whereby tooth to tooth end abutment is maintained between the rotor and annulus through one pitch of movement at the transfer zone between inlet and outlet ports of the pump or motor. In one embodiment described as a pump, a plunger 12, Fig. 2, loaded by a blade spring 13 slides in the casing 9 to urge an annulus 2 towards a rotor 1 over a transfer zone T between suction and delivery ports 10, 11 so that teeth 5, 6 are in ribbing engagement and the annulus is urged towards the rotor to decrease the eccentricity c between axes 3, 4 of the rotor and annulus respectively. Clearance 14 may be connected to the delivery port 11 by a duct 17 to hydrostatically balance bursting stresses acting on the annulus and by a duct 16 to the space behind the plunger 12 to assist or alternatively replace the spring 13. Guide rollers 15 prevent undesired side or orbiting movement of the annulus 2. One or both sides of the rotor 1 and annulus 2 may be engaged by pressure plates 24, Fig. 4, whose rear faces are subjected to pump discharge pressure to seal the pump chambers. In another embodiment, the rollers 15 may be replaced by pressure pads 15a, 15b, Fig.6, sub-dividing the clearance 14 into chambers 14a, 14b, with the chamber 14a connected by a duct 17a to pump discharge 11 so that a spring-loaded plunger 12a is assisted by pump discharge pressure. The chamber 14b is connected to the suction side of the pump by a duct 20 and the pad 15b is loaded by a spring 15c to function as a pressure relief valve. Alternatively or additionally a resilient insert may be provided in each gap 8 between the teeth 6 on the element 2. Alternatively one or other of the elements may be made from a resilient material such as hard rubber. Channels communicating with the pump chamber cut in the casing side plates permit lubrication between the elements and the side plates. The invention permits any wear on the teeth of the elements to be taken up. Other embodiments are also described.