GB462668A - Methods and apparatus for regulating free piston gas compressors - Google Patents

Abstract

462,668. Free - piston compressors. PESCARA, R. P. Sept. 9, 1935, No. 25103. Convention date, Sept. 7, 1934. [Class 8 (i)] In a free-piston compressor wherein the power unit is an internal-combustion engine having a device for regulating the quantity of fuel supplied thereto in accordance with the length of stroke of the piston of the engine, the regulating device is controlled in accordance with the pressure prevailing in the pressure chamber at the end of the compression stroke or in an auxiliary chamber of the apparatus. The injection unit 11 of the engine is controlled by a slide 10 which is actuated by a piston 9 receiving fluid from the pump 7 in accordance with the position of a valve 8. The pump 7 is operated by cam gear 12 operated by linkages from one of the reciprocating parts, whilst the valve 8 is under spring restraint 19 and subjected in the chamber 17 to the pressure prevailing in the compression space 3. The pump 7 normally pumps from a tank 14 and when the valve 8 is in the neutral position, corresponding to normal piston stroke, through a return valve 24, but with the valve in the position shown liquid is pumped past the hollow portion 20 of the valve through the conduit 27 to the underside of the piston 9 thereby altering the slide control 10 of the injection unit. In another form, the acceleration of the reciprocating piston which is proportionate to the final compression pressure is utilized. In this case a cylinder 49 is carried by one of the reciprocating members which contains a piston 50 having a non-return valve 60 and acting under spring restraint 49. According to the acceleration as the cylinder is reciprocated, the piston will take up varying position against the spring 49 and so pass fluid through an opening 53 and pipe line 55 to the underside of the control piston 9. As before, the plunger of the injection pump 11 is operated by a cam 13 carried by a reciprocating rod 13<1> and is governed by a slide member 10. In a further modification, an indicator 62 is provided which is moved by the rod 73 of the control piston 9 and indicates the stroke on a scale 63. With abnormal strokes, the valve 66 on the rod 73 is positioned so that pressure fluid is admitted to the conduit 67 and acts on the piston 64 and the linkage 65 operates to cut out the injection unit 11 and stop the machine. A further control is dependent upon the pressure in the reservoir, such pressure acting on a piston 70 which moves a cam 71 over the end of the floating lever 72. In modifications, the pressure in the buffer cylinder and other like auxiliary chambers is utilized to act upon the control valve 8.