Patent GB-664202-A (GB)
Title: Improvements in or relating to starting internal-combustion operated free-piston power-plant, such as combustion product generators
IPC: F02C5/08
Filed: 1949-06-14
Abstract: 664,202. Free -  piston gas - generators ; starting. SOC. D'ETUDES ET DE PARTICIPATIONS EAU, GAZ, ELECTRICITE, ENERGIE SOC. ANON. June 14, 1949 [June 16, 1948], No. 15874/49. Classes 7(i) and 7(v) . In a starting control device for freepiston power plants such as internal-combustion, combustion product generators including at least two free-piston gas generators A and B, Fig. 1, each of which is provided with at least one starting chamber into which gas under pressure is introduced for starting purposes through a pneumatically operated starting valve 12, and respective pneumatic operating means, such as piston 15 and cylinder 14. being caused to operate by the movement of a common operating member, for example, manual valve 24; there is provided means. such as conduits 19 of different lengths and/or cross-sections, for 'regulating the velocity of flow and/or the quantity of gas in the respective gas streams in each conduit 19 by means of which the opening of the valves 12 is effected in such a manner as to produce a lag between the opening of one valve 12 and the opening of the other or others. In the end wall 7a of each compressor cylinder is an orifice 11 -controlled by one of the valves 12 to the stem of which is attached the piston 15 sliding in the cylinder 14, the piston having a passage 17 therethrough. The passage 17 is controlled by a check valve 18 that opens into a chamber 13 above the piston 15 and the valve 12 is normally closed by a spring 16. The underside of each cylinder 14 is connected through one of the conduits 19 to a control member or valve 24 that either connects each conduit 19 to a compressed air supply or to exhaust. The conduit 19 leading to generator B is different from that leading to generator A in that it either includes a part of different length and/or crosssection for a portion of its length or as shown embodies a check valve 25 which is byepassed by a conduit 26 of reduced crosssection. When air is admitted by valve 24 to both conduits 19 it enters the two chambers 13 via valves 18, the valve 24 then being moved to open both conduits to atmosphere. The air underneath the pistons, 15 of generator A thereby escapes to permit the air in the corresponding chamber 13 to open valves 12 and enter the starting chamber beneath the compressor pistons 6 to start the generator. However, the presence of valve 25 and conduit 26 causes the air flowing to atmosphere from the underside of piston 15 of the generator B to be retarded so that the latter starts 180 degrees or an odd multiple of this value behind generator A. In a modification, as applied to two aligned generators, the air enters the chamber 13 through valves 29, Fig. 2, and cylinder 14 through valves 30 as well as acting on a piston 32 attached to a valve 31 to keep the latter closed. When valve 24 is operated to connect conduit 33 to atmosphere, the air in cylinder 14, which acts on the underside of piston 32 through orifices 35a and 35b, now moves the latter inwardly to open valve 31 to permit the air in these chambers to escape to atmosphere. Since the orifice 35a is larger than orifice 35b the left-hand chamber 14 empties first and so causes the corresponding generator to start first. The chamber 13 of the righthand generator is charged to a slightly higher pressure than the left-hand chamber by providing weaker springs to load the associated valves 18 or 29. The out-ofphase starting of the machines may also be obtained by making each spring 16 of different strength or by filling each of the cylinders 14 with air at different pressure. The opening of valves 12 could be effected by pressure air instead of connecting the underside of pistons 15 to atmosphere. A device may be provided to maintain the generators in operation with the same phase difference as obtained at starting. Specification 633,863 is referred to.