Patent GB-606358-A (GB)
Title: Improvements in and relating to compounding systems for steam locomotives
IPC: F01K15/02
Filed: 1945-12-20
Abstract: 606,358. Locomotives. SUPERHEATER CO. Dec. 20, 1945, Nos. 34526 and 34527. Convention dates, Jan. 11 and Sept. 13. [Class 79 (i)] [Also in Group XXVI] A locomotive comprises a turbine having means for varying the volume of steam admitted thereto and a reciprocating engine with variable cut-off, both being coupled to the driving wheels, together with means for admitting unthrottled superheated steam at constant pressure to the turbine and for exhausting steam from the turbine to the reciprocating engine. The whole of the turbine exhaust may be fed to the reciprocating engine, or in the case of high boiler pressures, some steam may be bled from the turbine at an intermediate stage thereof, and the balance utilised for draught purposes and/or for pre-heating the boiler feed water. When operating in reverse, the turbine may be byepassed, steam going direct to the reciprocating engine. As shown, the locomotive comprises a boiler 1, the steam from which passes through a superheater header 3, and pipe 4 to a valve chest 5. Pipes 8a, b, c, d connect the valves 5a with nozzles 6 of a steam turbine 7. Exhaust steam from the turbine is fed into the cylinders of the reciprocating engine 11. Both the turbine and reciprocating engine are adapted to drive the main driving wheels of the locomotive through gearing 21, 23, 24 and through the usual connecting rods 18 respectively. The valves 5a in the turbine valve chest 5 vary the volume of steam admitted to the turbine and are controlled from the cab by a hand-wheel 33 operating shafts 32, 31 and gearing 29, 30. Means are provided for altering the valve cut-off for the reciprocating engine, comprising a lever 25 mounted in the cab, operating rods 26, 28, the latter being connected to a valve operating gear 15. A gauge 39, Fig. 5, located in the cab records the pressure of the partially expanded steam in the pipe 9 between the turbine and the reciprocating engine. Fulcrummed on the pointer axis is another pointer which indicates the cut-off position of the valve 12 and is connected to the operating lever 25 by an adjustable push-pull control 42, Fig. 5. The scale 44 indicates the steam pressure and scale 45 to cut-off position, the latter being adjusted so that when the pointers coincide, the reciprocating engine is working at optimum cut-off for the steam pressure supplied to it. When starting, the lever 25 is adjusted to give the longest possible cut-off to the valves 12, indicated by the gauge pointer 41 being in its extreme right position, and steam admitted into the turbine in such quantity as will not cause wheel slip. The pressure in the pipe 9 connecting the turbine and reciprocating engine will be the maximum boiler pressure and will be indicated by the gauge pointer 51 in its extreme left position. As the locomotive accelerates, more turbine valves are opened and the pressure in the pipe drops. The valve cut-off is then adjusted so that the pointers 41, 51 coincide for optimum working conditions. In locomotives using higher steam pressure, e.g. over 300 lbs., the amount of steam used by the turbine is limited by the displacement of the reciprocating engine, whose size must not cause wheel slip. In such a case, steam for the reciprocating is tapped off from an intermediate position in the turbine, e.g. by a pipe 62, Fig. 6, the balance of steam passing through the turbine exhausts into the smoke stack by a pipe 61. Feed water heaters 68 and 72 may be provided to further utilise heat from the turbine exhaust. A valve 63, operated manually or automatically, e.g. by hydraulic pressure from a pump 65 driven by the turbine, may be opened when a predetermined turbine speed is reached, allowing turbine exhaust steam to escape into the smoke-stack. U.S.A. Specification 2,102,806 is referred to.