GB816556A - Improvements relating to rotary pumps and motors - Google Patents

Abstract

816,556. Rotary engines &c. PRENDERGAST, C. S. Dec. 30, 1957 [April 15, 1957; Oct. 23, 1957], Nos. 12298/57 and 33098/57. Class 110 (2). Sliding vane pump or motor having three circular rotors 4, 5, 6 keyed to a coaxial shaft 1 between end casings 2, 3, the outer rotors 4, 5 being provided with fixed eccentric stators 9, 10 while the eccentricity of the stator 11 of the rotor 6 can be adjusted by screw means to vary the output of the pump between zero and a maximum. Partitions 7, 8 separating the rotors have peripheral grooves 7A, 8A closed by casing rings 7B, 8B, while grooves extending over about 90 degrees of the periphery of stators 9, 10 are closed by casing rings 9B, 10B and communicate through radial passages respectively with an axially aligned passage 19 leading from an inlet port 20. Each rotor has eight equi-spaced radial grooves 15 in which vanes 16 slide, the outer end of each vane being shaped to conform to the bore of the stator. As fluid enters the stators 7, 8 from passage 19, the vanes driven outwards by centrifugal force entrain the fluid while sweeping across arcuate grooves 9C, 10C communicating with the quarter-circle grooves and force the entrained fluid through arcuate grooves 9D, 10D respectively communicating with the grooves in the partitions. In the adjustable stator 11 are two radial passages 11A, 11B communicating with an inlet port 21 and an outlet port 22 through arcuate grooves 12B, 12C, the groove 12C being in communication with the grooves 7A, 8A, so that fluid entrained by the rotors 4, 5 passes to the groove 12C and thence through port 22. When the relative eccentricity of the stator 11 and rotor 6 is in opposition to that of the outer pumping units, fluid entering by port 21 is entrained by rotor 6 and forced through outlet 22 in addition to that supplied by rotors 4, 5. If there is no relative eccentricity of stator 11 and rotor 6, the total displacement of the pump is from rotors 4, 5. When the relative eccentricity of stator 11 and rotor 6 is in the same sense as that of the rotors 4, 5, the rotor 6 absorbs the displacement of rotors 4, 5 and returns the fluid to the supply through port 21. The angular distances between the grooves in the stators are greater than those between any pair of adjacent vanes to provide a seal between the expansion and contraction chambers of each rotor.