GB190913653A - Improvements relating to Rotary Compressors and Vacuum Pumps or Exhausters. - Google Patents

Abstract

13,653. Pittler, W. von. Dec. 9, 1908, [Convention date]. Movable-abutment type; regulating pumps; starting. - Relates to rotary compressors or vacuum pumps having axiallysliding abutments. Means are provided for setting the abutments out of action when the desired pressure or vacuum is exceeded. The piston 3, a development of the periphery of which is shown in Fig. 4, is provided with projecting vanes 3<a>, 3<b> arranged symmetrically on either side. Each vane is provided with a packing-bar 7 and camsurfaces on either side against which the abutments 5<a>, 5<b> bear. Bushes 4 surrounding the piston shaft 2 guide the lower edges of the sliding abutments. The compressor, shown in the drawings, has a suction pipe 9 leading to ports 8, and discharge ports 10, provided with non-return valves, are arranged at the openings to the abutment-recesses, and lead to the pipe 11. The abutments are submitted to the pressure of the compressed fluid, which is admitted behind them by a cock 27, a pistonvalve, and passages 14<a>, 14<b>, 15, 16. The piston valve has two heads 17, 17<1> of different area, and the pressure of a spring 18 is so adjusted by a screw 19 that the valve is in equilibrium when the desired pressure is ob tained by the compressor. Any additional pressure will close the valve and shut off the fluid supply to the abutments, which will remain in the inoperative position. A screw 20 limits the downward motion of the valve, and a duct 21<1> affords communication with the atmosphere. An auxiliary reservoir 22 of compressed air, connected by a pipe 25 and cock 26 to the abutment casing, may be employed at starting, and springs may also be provided which can be rendered inoperative either automatically or by hand. A check valve 24 prevents the return of compressed air from the auxiliary reservoir 22 to the main receptacle, when the pressure in the latter decreases. The duct 12 and cock 27 may be omitted if the pipe 25 is connected to the valve-casing 13. The ascending slopes of the piston vanes 3<a>, 3<b> have a small gradient to prevent the abutments from being thrown back too violently when relieved of fluid-pressure.