GB595878A - Improvements in free piston gas generators - Google Patents

Abstract

595,878. Free piston gas generators. VICKERSARMSTRONGS, Ltd., and DAVIS, D. E. July 17, 1945, No. 18336. [Class 7 (i)] In a free piston gas generator of the type in which compressor pistons deliver during the working outward stroke of opposed combustion pistons in a common combustion chamber compressed air to be fed to the combustion chamber and having main pneumatic cushioning means which provide a cushioning action during the outward stroke and part of the necessary expansior. energy for driving the pistons on the inward stroke further pneumatic cushioning means are provided which form stabilising cushions which come into operation near the end of the inward stroke of the pistons to arrest them in the event of overstrokes at low gas pressures tending to cause the pistons in the combustion chamber to contact with each other whilst maintaining the compression pressure in the combustion chamber within the range required for efficient operation of the generator the stabilizing cushions being open to atmosphere and thus inoperative for the greater part of the inward and outward strokes. As shown opposed engine pistons 2, 3 having enlargements 7, 8 work in a common cylinder 1. The pistons 7, 8 compress air on each outward stroke in spaces 5, 6. At the rear of the pistons 7, 8 stabilizing cushioning spaces 5a, 6a, are provided. The main cushion spaces working during the outward stroke are arranged at 13, 14. The additional cushion spaces serve to prevent contact of the pistons when operating at reduced working pressure. Air is trapped in the cushions 5a, 6a when ports 15, 16 are covered by the enlargements. In a modification the positions of the compressor space and the main cushioning space are interchanged. In this case the enlargement of the piston works past a port in its cylinder which admits air to the cushion spaces on both sides of the piston.