GB773391A - Improvement in regulating method for free-piston compressors and apparatus for the regulation of such compressors - Google Patents

Abstract

773,391. Compressors. WACHSMUTH, E.A. Jan. 8, 1953, No. 602/53. Class 8(1) In an apparatus for varying the quantity of gaseous fluid delivered per stroke by a free piston compressor which includes a reciprocable piston 39 (Fig. 1)' in a cylinder 32 having an inlet valve 36, a hydraulically operable mechanism for holding the inlet valve open through a portionof the discharge stroke of the piston includes, in combination, hydraulically operable cylinder 61 (Fig. 5) and piston 62 mechanism for holding the inlet valve 36 open (via claws 60, Figs. 1 and 5), a hydraulic impulse giver 42 (Figs. 3 and 5) having means R<SP>1</SP> for varying the time it delivers its impulses, the impulse giver being connected to the hydraulically operable cylinder and piston 61, 62 so that the impulses delivered control the operation of the latter, and means 43 (Fig. 3) responsive to compressor discharge for adjusting the means R<SP>1</SP> for varying the time of delivery of the impulses by the impulse giver 42 to vary such time. The piston 39 is connected by a rocker arm 6 to a shaft 8 on which is mounted a cam 100 for reciprocating the plunger 51 of the impulse giver 42. As the plunger moves up the pressure medium in the space 53 is forced into cylinder 61 against the force of the spring 64 opposing movement of the claws 60 until the clawoperating piston 62 is stopped by the abutment 63 and the valve 36 is held open. As the oblique edge S of the plunger 51 moves upwards over the control port 52, the presure in the system is relieved and the spring 64 withdraws the claw to close the valve 36. The plunger 51 continues its upward movement to expel pressure medium from space 53 through the laterally vented central bore in the plunger and the central port 52 into the space 55 which communicates with the suction space 57 through a throttle gap 56. When the plunger 51 moves down, the suction valve 46 opens. The time at which, during the upper stroke of the plunger, the oblique edge 5 reaches the port 52 depends on the angular position of the plunger and this is controlled by the rack bar R<SP>1</SP>. Gaseous fluid delivered by the compressor is conveyed by a line 89<SP>1</SP> to the device 43 and acts upon spring loaded piston 95, movement of which is transmitted via a lever 88 to the control bar R<SP>1</SP>. The end 90 of the bar is connected to a device which controls an element R governing the delivery of the fuel pump P to the motor cylinder of the compressor (also see Specification 773.392).