GB1292046A - Improvements in or relating to power plants for use in a high-pressure environment - Google Patents

Abstract

1292046 Power plant PLESSEY CO Ltd 16 Jan 1970 [24 Jan 1969] 4256/69 Heading F1Q [Also in Division F4] A power plant for use in a high-pressure environment, e.g. for propulsion of a submarine, comprises a reaction chamber into which are introduced materials for an exothermic chemical reaction, a fluid-pressure motor driven by the vapour produced in the reaction chamber, and means for condensing the vapour leaving the motor by transfer of heat to the high-pressure environment. In one arrangement, Fig.1, a reaction chamber 3 can be supplied through orifice 18 with a fuel metal in liquid or extrudable form from tank 1 and through orifice 19 with a concentrated hydrogen peroxide solution from tank 2, the tanks 1, 2 containing respectively a piston 15 and membrane 16 pressurized by a nitrogen bottle 12. The fuel metal is an alkali metal or an earth alkali metal from the lower numbered periods of groups IA and IIA of the periodic system. The metal and H 2 O 2 react exothermally in chamber 3 and the steam formed passes through a valve 20 and nozzle 4 to drive a turbine 5 connected to a propeller 8. The steam exhausting from turbine 5 is condensed in a surface condenser 11 cooled by water taken from outside submarine hull a, the condensate being ejected through an outlet e in the hull by a pump 7 driven through gearing 9. The latter also drives a pump 6 which takes in outside water through an inlet b and injects it through an orifice 10 into the reaction chamber 3 to provide additional steam. Valve 20 can control the steam flow to turbine 5 in response to a turbine speed signal which may be sensed via line f as the delivery pressure of pump 6 or the pressure rise therein. Alternatively the pump pressure signal can control the speed by acting on valve 14 via line g to control the nitrogen pressure in tanks 1, 2. In a modification, Fig.3, the concentrated H 2 O 2 is stored in a tank 52 pressurized by outside water admitted through pipe 73 and the fuel metal is stored in a container 51 through which heat exchanger tubes 53 extend to permit the metal to be kept molten during operation. The H 2 O 2 is forced by pump 56 from tank 52 to a chamber containing a catalyst bed 60 which may comprise platinized asbestos, stones impregnated with potassium permanganate solution, or silver plated wire gauze. The H 2 O 2 decomposes into steam and oxygen in passing through bed 60 and the hot products pass through heat-exchanger tubes 53 into a chamber 61a containing the fuel metal pump 57 which is thus heated. The hot products then pass through a perforated partition 64 into the reaction chamber 61 to react exothermally with the fuel metal injected through nozzle 62, additional steam being formed by water injected into the chamber through a nozzle 77. The latter receives its water supply from outside hull a via a pump 58, line 78a, passages 75a in partition 64, annular manifold 75 and a cooling jacket 76 surrounding the chamber 61. Excess water from jacket 76 is returned through line 84 to the condenser cooling water downstream of condenser 71. The steam leaving chamber 61 drives a turbine 67 &c. as previously described. Starting can be effected by a cartridge 80 which directs gases through a nozzle 81 on to the turbine 67 to drive pumps 56, 58, 59, rotation of fuel metal pump 57 being prevented by a slipping or disengageable clutch 79 until the metal has melted. An electric heater 55 may be provided to melt the metal prior to starting. Instead of using cartridge unit 80 starting can be effected by an electric motor 82 driving through a clutch 83. Valve 66 is controlled in response to turbine speed sensed by a centrifugal governor or an electric tachogenerator or sensed as the output pressure or pressure rise of water pump 58 or the output pressure of H 2 O 2 pump 56. If the submarine is intended to operate at great depths the cooling system may be arranged to operate at a lower pressure than the water pressure outside the hull a. In this case pump 58 is replaced by a pressure reducing valve 85 while a pump 58a is fitted in the coolant outlet line 71a. A further slightly modified embodiment is illustrated in Fig.2 (not shown).