Patent GB-433631-A (GB)
Title: Improvements in or relating to internal combustion turbines
IPC: F02C3/36
Filed: 1934-02-19
Abstract: 433,631. Gas turbines. RODDAM, G., 10, New North Road, Bourda, Georgetown, Demerara, British Guiana. Feb. 19, 1934, No. 5399. [Class 110 (iii)] Pure turbine plant on a cycle in which the working fluid is compressed isother mally and then re generatively heatec by the exhaust gases before combustion and expansion, com prisesahigh-temper ature high-pressure turbine mechanically coupled to an isothermal compressor and a lower temperature lower pressure load turbine fed from the exhaust of the first turbine, with a governor controlling the supply of fuel to the combustion chamber, which feeds the first turbine. On reduction of load the restriction of fuel supply by the governor causes a reduction of the working fluid temperature, so that the speed of the first turbine and compressor is reduced and the temperature and pressure of the exhaust from this turbine are adjusted to the requirements of the load turbine ; the reduction of efficiency due to the decreased temperature is balanced by an increase due to the lower compression pressure. The first turbine preferably has a high heat drop in the first pressure stage, which may be relatively inefficient but serves to reduce the temperature to a safe value for the rotor and to localize the effects of high temperature ; the losses in any case appear in the heat of the working fluid and are recovered in the load turbine and regenerator. The primary stage of the first turbine may be velocity compounded, and may be followed by additional impulse or reaction stages of low heat drop. The first turbine, driving the compressor and other auxiliaries, is mechanically independent of the load and may therefore be designed for high speed, with a small rotor which may then be constructed of special metals. Starting is done by stored compressed air, the burners being ignited by electrically heated ignition points or sparking plugs. Where the load is reversible, a separate reverse power turbine is provided, the exhaust from the high-temperature turbine being diverted to this when required. The nozzle 1 of the combustion chamber is supplied through pipe 8 with fuel and through pipe 25 hot compressed air in the correct quantity for best combustion, and is surrounded by a wall 6 which protects the casing 5 from the highest temperatures of combustion ; additional diluent air is admitted to the chamber by pipe 16 to mix with the working fluid after combustion. In order to minimize distortion due to the high temperature and pressure, in the form shown the forward part of the combustion chamber and the high-temperature stage of the turbine are jacketed by the hot compressed air passing from pipe 7 through spaces 13, 14 before entering the combustion chamber ; the pressure on the walls of the parts is thus balanced and transferred to cooler outer walls, and radiation loss is reduced. According to the Provisional Specification, in cases where the plant can be started under " no load " conditions the two turbines may be geared together, the load on the gearing being reduced by the connection of the high-temperature turbine to the compressor ; the compressor may have a second stage driven by the load turbine.