GB594764A - Improvements in free piston type internal combustion compressors - Google Patents

Abstract

594,764. Combustion-product plant. ENGLISH ELECTRIC CO., Ltd., and WELSH, R. J. Feb. 11, 1944, No. 2595. [Class 7 (i)] In an internal-combustion compressor of the free-piston type and comprising two opposed pistons operating in a common cylinder, a synchronising linkage between the pistons is omitted and the pistons have an inherent tendency to return to inner dead centre positions symmetrically disposed about a selected transverse plane through the cylinder. Opposed pistons operating in an engine cylinder 1 are each integral with a compressor piston 5 in a pump cylinder 2 and a buffer piston 6 in a cushion cylinder 3, the engine cylinder having inlet ports la connected by passages 15 with the delivery outlets of the compressors and exhaust ports 16 leading for example to a gas turbine. Fuel, ignited by the compression, is supplied through an injector 9 by a pump 30 actuated by fluid pressure from the combustion space as described in Specification 226,523, [Class 7 (iii)], the pump plunger being cleaned by an air blast taken from a cushioning space 3 through a narrow pipe 8. Linked throttles 20 control the inlets to the compressors. In operation, if a piston makes an unusually long stroke the pressure in the cushioning chamber 3 rises abnormally and although the energy in the air trapped in the buffer chamber 3 decreases, the chambers are so proportioned that more energy is availableto return the piston. The abnormal pressure ejects air past a non-return valve along a pipe 24 depresses a spring-pressed piston 26 in a cylinder 25 before the excess pressure is relieved through an escape port 25a. Displacement of the piston rocks a lever 28 to actuate the fuel regulator 30a of the pump 30 to reduce the charge for the next impulse and the increased pressure in the cushioning chamber 3 returns the piston assembly to its normal inner dead centre position, an escape port 3a in the chamber 3 limiting the operation of the pressure or the chamber may be provided with automatic inlet and outlet valves 17, 18, the latter being spring loaded. Alternatively, the piston 26 may operate the air throttles 20 and the fuel control be manual. A narrow pipe 19 connecting the cushioning chambers 3 damps piston oscillation at the inner dead centre position. The leak 25a in the cylinder 25 may be replaced by a servo-motor adapted to supply pressure fluid to or drain off from. the cylinder 25. In the case of a vertical engine, pressure reservoirs are employed to balance the weight of the two piston assemblers either as a whole or individually. A running indicator constructed similarly to the cylinder 25 and piston 26 may be provided on the pipe 24. Specifications 586,989, 595,546, [Group XXVI], 595,547, and 598,530 ,also are referred to.