GB701503A - Improvements relating to gas turbine power plant - Google Patents

Abstract

701,503. Gas turbine plant; centrifugal compressors. CENTRAX POWER UNITS, Ltd., and BARR, R. H. H. March. 10, 1950 March 25. 1949; July 4, 1949 ; Aug. 19, 1949], Nos. 8252/49, 17625/49 and 21602/49. Classes 110 (1) and 110 (3) A gas turbine plant including a centrifugal compressor having a vaneless annular diffusing space, combustion apparatus and a turbine sys, tem) comprising one or more turbines each of which is a single stage inward radial flow turbine, to drive the compressor and supply external power, has adjustable nozzle means through which the working fluid is continuously admitted to substantially the whole circumference of the turbine rotor or rotors and control means for varying the quantity of fuel fed to the combustion chamber both of which means are so interdependent that a variation in mass flow effected by adjustment of the nozzle means is associated with a corresponding variation in the quantity of fuel, burnt. The gas turbine plant, Fig. 7, comprises a compressor A which discharges through a heat exchanger D to a combustion chamber E where fuel is burnt. The combustion gases from the chamber E pass to a turbine B which drives the compressor A and a useful power turbine C arranged in series. The compressor A has an impeller 1, Fig. 6, which sucks in air through the intake 2 and delivers it into a vaneless diffuser space 3, the outside diameter of which is at least one and a half times the impeller step diameter. The gases from the combustion chamber E are led to a volute 11 giving access to a variable admission nozzle ring 12 of the radial-vaned centrifugal flow compressor driving turbine B which exhausts to a power turbine C of similar type controlled by a variable admission nozzle ring 20. The shaft 23 of the turbine C is arranged at right angles to but does not intersect the shaft 18 of the turbine B so that the duct leading to the volute 19 can be short and almost straight. The nozzle vanes 12; Fig. 9, are mounted on stub pins 13 so that they can be adjusted. The pins 13 carry short levers 14 the free ends of which carry pins 14a engaging radial slots 29 in an annulus 30 supported on rollers 31. The annulus 30 has internal teeth 32 engaged by a pinion 33 mounted on an operating arm 35. The vanes 20 are actuated by similar mechanism. The plant is controlled by a single accelerator pedal 36, Fig. 11, linked to a shaft 37 which through bevel gears 38 rotates a shaft 39 carrying lever arms 40, 41, 42 linked to rods 43, 44 and 45. The rod 43 operates a throttle valve 46 located in the spill line from the burners 8, the rod 44 moves a lever 35 operating the nozzle vanes of the turbine B and the rod 45, through a member 47 provided with a cam slot 48, actuates a lever 49 which adjusts the nozzle vanes of the turbine C. Actuation of the pedal 36 alters the fuel supply and at the same time brings about an appropriate variation of the mass flow through the turbine. An alternative form of construction for the compressor A Fig. 12, comprises the arrangement after the diffusing space 3 of a secondary diffuser consisting of diverging passages defined by fixed vanes 50. In a further modification, the compressor is as described in Specification 701,560, in which the secondary diffuser is located parallel to the axis of the compressor and the diffusing action is obtained by diverging the walls of the casing. In a still further modification, the gas supply to the turbines B and C is controlled by a pivoted flap mounted in the inlet to the volute 11. The invention may be applied to a plant having a single turbine, i.e. the compressor turbine or a plant having a number of useful power turbines. The latter arrangement may be used in a vehicle and one turbine may be connected to the wheels on one side of the vehicle and another turbine to the wheels on the other side. According to the first Provisional Specification, the compressor may be of the normal type provided with pivoted diffuser vanes. It is also stated that in the arrangement using two useful power turbines attached to the wheels of a vehicle the two turbines may be arranged back to back and supplied with working fluid through one set of variable nozzles. This arrangement may be used to give a differential effect so that retardation of one turbine accelerates the other. According to the second Provisional Specification, the adjustable nozzle guide vanes of the useful power turbine may be moved from one position in which the turbine rotates in one direction to another in which it rotates in the other. Specification 701,552 also is referred to.