GB497005A - Improvements in and relating to internal combustion driven free piston air or gas compressors - Google Patents

Abstract

497,005. Hydraulic transmission of power; hydraulic accumulators ; directacting compressors; reciprocating pumps. PESCARA, R. P. May 11, 1937, No. 13454. Convention date, May 12, 1936. [Class 69 (ii)] [Also in Group XXVIII] In an internal-combustion-driven free-piston air or gas compressor, one or more rotary auxiliary machines, such as a water pump, a lubricating pump or a fan, are driven by a hydraulic pump-and-motor transmission, the pump being connected with a reciprocating or oscillating part of the compressor ; the auxiliary machine being of the kind having a gradual starting and a continuous rotary movement when running, means are provided for storing up some of the hydraulic energy developed by the pump when this is in excess of that required by the auxiliary mechanism and for giving this up when the latter is in a, condition to receive it. One piston A, 4 of the compressor, Fig. 1, is directly connected to the pump comprising a double-acting piston 9 delivering to a gear motor 7 ; a make-up reservoir 38 and air bottle 29 are provided. The air bottle may be replaced. Fig. 2 (not shown), by a spring- loaded piston adapted at excessive pressure to open a byepass. Alternatively, the pump may comprise, Figs. 3, 4, 7, pistons 14, 15 reciprocated by means of a crank pin 18 on a shaft 5<1> coaxial with the shaft 5 of the normal synchronizing linkage; the shaft 5<1> may be integral with the shaft 5, as shown in Fig. 3, a spring 26 acting on a packing 24, 25, or the shafts may be coupled, as shown in Fig. 4, by a leaf spring 27 which acts on the packing. The casing 37 of the compressor may be used as a reservoir for the scavenging air; air leaking past the bearing 5c is vented by passage 42 and charges the reservoir 38, Fig. 3. Alternatively, the reservoir 38. may be charged by some of the liquid from the lubricating pump 2, Fig. 4. The transmitter pump may be supercharged. The hydraulic transmission means may be provided with cooling fins 40 in the zone of action of the fan 3. The accumulator comprises a spring-loaded differential piston 30, Fig. 7, one of the pump plungers delivering to the motor through a bore 34 in the piston ; under excessive pressure the piston uncovers byepass ports 35. In order to compensate for the fact that the speed of the compressor piston on its outward stroke differs from that on its inward stroke, the two pistons of the pump may be of different areas so as to maintain a constant rate of delivery to the motor, Fig. 8 (not shown). In order to cushion the compressor piston at the ends of its stroke, the ends of the pump cylinder may be provided, Fig. 9, with conduits 41, 41<1> permitting restricted discharge when the delivery ports are over-run.