GB1158314A - Rotary Pumps or Motors of the Radially-Slidable Abutment Type. - Google Patents

Abstract

1,158,314. Rotary pumps and motors. DOWTY TECHNICAL DEVELOPMENTS Ltd. July 25, 1966 [July 29, 1965; Dec. 16, 1965], Nos.32441/65 and 53535/65. Heading F1F. [Also in Division G3] A rotary pump, compressor or motor of the radially-slidable abutment kind, as described for compressing gaseous refrigerant in the refrigeration system of a motor car, comprises a casing 12, Fig. 2, having an inlet port 11, and outlet port 42 controlled by a leaf-spring valve 43, and at least one radially-sliding abutment 32 between the inlet and outlet ports normally urged by a torsion spring 34 into sealing engagement with a ring member 27 bearingly mounted on an eccentrically mounted rotor 18 and liftable against the torsion spring 34 to remove the abutment away from the ring member 27 to put the inlet and outlet ports into direct communication with each other to render the compressor inoperative. The torsion spring 34 is carried by a rod 39 to which a bell-crank 63 is fixed with one end of the bell-crank engaging the spring and the other end in engagement with a spring-loaded piston 66 whose movements are controlled by a solenoidactuated spool type valve 69, Fig. 4. A rotary positive-displacement pump 55, Fig. 1, coupled to and driven with the rotor 18 sucks in lubricant from a reservoir 23 through a pipe 57 and delivers it through a line 59 to bearings 16, 20 supporting the rotor 18, and bearings 25, 26 supporting the ring member. At the same time the output from the pump 55 is used to operate the piston 66. In normal operation, the solenoid actuating the valve 69 is de-energized and the valve is positioned to direct lubricant to act on both ends of the piston 66 whence the spring 66a urges the piston rightwardly so that the abutment 32 engages the ring member 27. On energizing the solenoid, the valve 69 is positioned to cut off the supply of lubricant to the spring side of the piston 66. The piston then moves leftwardly to lift the abutment 32 away from the ring member 27 and uncover a passageway 72 through which lubricant passes to the bearings which would otherwise be starved of lubricant. In another embodiment, a solenoidactuated valve 144, Fig. 9 is operated in accordance with temperature in the car. With the solenoid energized, the valve spool 145 is displaced so that a groove 149 directs low-pressure refrigerant from a branch 139 connected to the compressor inlet line 117 via a chamber 151 and connection (not shown) to a chamber 152 above a piston 133 operably connected to the pump abutment member 120. The larger lower area of the piston 133 is also subjected to the pressure in the compressor inlet line 117 whence the piston is moved upwardly and held in that position by a spring-pressed detent 138 so that the abutment 120 engages a member 115 surrounding the compressor rotor 114. On a sufficient fall in temperature in the car the solenoid actuating the valve 144 is de-energized whence the valve spool 145 moves rightwardly under the action of its spring 145a to close the groove 149 and open a groove 148 whence refrigerant at compressor discharge pressure within the casing 116 is directed to the chamber 152 above the piston 133 to move it downwardly to lift the abutment 120 away from the member 115 so that the compressor idles. The fall in compressor discharge pressure causes a non-return ball valve 128 in a branch line 127 from the pump discharge line 118 to snap closed and so maintain the pressure in the casing 116 to hold the piston in its downward position until the solenoid actuated valve is again operated by a temperature change.