GB438418A - Improvements relating to the method of and apparatus for starting multi-stage free-piston compressors - Google Patents

Abstract

438,418. Free - piston compressors. JUNKERS, T., (Representative of JUNKERS, H.), 18, Hindenburgstrasse, Gauting, Munich, Germany. July 30, 1935, No. 21606. Convention date, Aug. 11, 1934. [Class 8 (i)] For starting a multi-stage free piston compressor by compressed gas admitted to the compressor side of the apparatus a gas is employed with pressure greater than that of the final compression pressure and is admitted to one or more but not all of the compressor stages. When starting gas is to be admitted to the high pressure unit there is fitted an admission chamber 31 connected by a pipe line 32 with the storage supply tank 34 and in valved communication with the cylinder 6. The valve 28 carries on its stem a larger piston 29 which is under spring control 30 and has a balanced connection by means of a connecting pipe containing a loaded valve 35 with the chamber 31. On opening the valve 33, starting gas is admitted past the valve 28 to move the piston 4 and thereafter is closed by the redistribution of pressure on the piston 29. In some cases, the valve is provided with a small aperture to provide a slow leak, and a similar leak aperture 38 is used for the chamber 36. When the engine starts a portion of the re-compressed starting air is discharged past the valve 41 which has an adjustable spring 27. In a modification, further valved connections are employed so that the working cycle is established after the first double stroke. In a further modification, the parts are held in the starting position by a pawl which is controlled by the starting gas and released in proper sequence. This pawl is itself restrained from re-locking the parts during the working period.