GB428418A - Improvements in or relating to multi-stage free-piston compressors - Google Patents

Abstract

428,418. Air-compressors. JUNKERS, H., 21, Hauptmann, Loeper Platz, Dessau, Anhalt, Germany. May 22, 1934, No. 15308. Convention date, May 20, 1933. [Class 8 (i)] A multi-stage compressor actuated by an opposed free piston internal - combustion engine, the opposed masses being coupled together for working in unison, is characterized by the disposition of the working diameters of the compressor asymmetrically on the two sides of the engine, the volumetric or pressure ratio of the compression chambers being such that the rate of doing work in the compressor on the working stroke on each side of the engine is substantially the same and the rate of doing work in the compressor to return the moving masses is also substantially the same on each side of the internal-combustion engine. The cylinder 1 of the internal-combustion engine has opposed pistons 2, 3 which are linked by rack gear 12, 12<1> and pinions 13 for working in unison. The pistons are continued and carry compressor pistons 8, 10, 21. The first stage compressor piston has its cylinder portion 9 provided with inlet valves 14 and outlet valves 15. The compressed gas passes through the pipe 16 to the inlet valves 17 of the second stage compressor 11 and is delivered past the outlet valves 18 through pipe 19 to the inlet valves 20 of the high stage compressor 22 and thence by delivery valves 23 to the storage chamber. The inner side of the piston 8 may be used in conjunction with the chamber 30 for supplying scavenging air to the engine. The inner side of the piston 21 may also be similarly used for doing work. When it is necessary to increase the piston area in any one stage to a greater extent than is obtainable by increasing the volumetric ratio, it is necessary in order to prevent absorption of energy rising too high, to arrange for a portion of the indrawn gas to be ejected at the beginning of the working stroke, and this is arranged for by providing delivery valves 24 through which a portion of the gas drawn in through the valve 17 is returned to the receiver 16 at the beginning of the working stroke until the piston 10 has masked the valves 24. Similar discharge valves 25 are provided in the first stage and the air thus discharged is used to supplement the scavenging air.