Patent GB-725816-A (GB)
Title: Improvements in or relating to internal-combustion-operated free-piston gas-generators
Inventor: LOVATT BERNARD CHARLES
IPC: F02B71/04
Filed: 1953-02-05
Abstract: 725,816. Free-piston gas generators. MUNTZ & CO., Ltd., A. Jan. 28, 1954 [Feb. 5, 1953], No. 3328/53. Class 7 (1). [Also in Group XXVIII] In an internal combustion operated free piston gas generator of the inward compressing type including a compressor cylinder 17 having a detachable cover 44 at its outer end and closed at its inner end by means of a head plate 28 in which are mounted delivery valves 27 through which gas compressed in the compressor cylinder is delivered to an engine case 26 the head plate has an outer diameter small enough to pass through the compressor cylinder bore is adapted to be removed together with the valve or valves therein without the need to remove the compressor cylinder and is provided with water cooling passages 45, 48 extending radially between adjacent delivery valves and communicating through axially directed ducts 46 with water cooling passages in the engine case. As shown the head plate 28 is held in place by socket-headed bolts 36 provided with nuts 37. The nuts are prevented from rotating and falling to the left (Fig. 2) by means of retaining straps 38. The delivery valves 27 are detachably secured by clamps 42. Cooling water enters at 50. Two plugs 52 are provided in a circular duct 47. Thus water passes around the lower half of the duct 47 and inwards through radial passages 45 to an annular duct 48. From the duct 48 it flows outwardly through upper passages 45 into the upper part of the duct 47 and flows out through the outlet 51. The plugs 52 allow slight leakage so that air on the lower side of the plugs can escape into the upper part of the duct 47. The duct 47 communicates through ducts 53 one of which is provided between each adjacent pair of suction valves 32 with cooling passages 54, 55. To restrict the flow through the passages 53 the annular passage 54 is separated from the main water jacket 55 by an outwardly projecting flange 56. The annular passage 54 is blocked up more or less completely at two points at opposite ends of a horizontal diameter. At each side of each of these two blocks an axial groove (not shown) is cut in the flange 56 to communicate with the water jacket 55. Thus the water flowing into and circulating around the bottom half of the passage 54 must in order to reach the upper half of the passage 54 all pass through the two grooves below the blocks into the water jacket 55 and back again into the upper half of the passage 54 through the two grooves above the blocks. An additional groove not shown may be cut in the flange 56 at its highest point to allow heated water in the jacket 55 which tends to collect at the top together with any air to escape. The delivery valves may be of rectangular shape and arranged on two concentric annular belts in the head plate the valves in the outer belt having their longer dimension approximately tangential with respect to their belt and the valves in the inner belt having their longer dimension approximately radial. The compressor 16 also comprises a head plate constructed as described. During the outward stroke the piston 14 uncovers exhaust ports (not shown) and shortly afterwards the piston 11 uncovers scavenging ports (not shown). Racks 19, 20 have portions of circular cross section guided in sleeves 23 (Fig. 3), A suitable form of exhaust manifold and other details are disclosed in Specification 726,215.