837,743. Gas turbine plant. ROLLS-ROYCE Ltd. Dec. 31, 1957 [Jan. 4, 1957], No. 607/57. Class 110 (3). [Also in Group XL (a)] A turbine and a recuperator unit for use in a closed cycle gas turbine plant comprises a pressure carrying casing 35 having at least one removable closure plate 36 which accommodates within it a compressor system 10, 12 driven by a turbine system 15, a recuperator 13a, 13b for heating the air supplied to the heater by the turbine exhaust gases and a power turbine 17 ; the pressure carrying casing 35 also has means to divide it into a number of spaces forming parts of the gas flow path for the power plant. The invention is described with reference to a closed cycle gas turbine plant in which air compressed in a low-pressure compressor 10 is passed through an intercooler 11 to the highpressure compressor 12 which discharges through a recuperator 13a, 13b and heater 14 to a highpressure turbine 15 driving the compressors 10, 12 and a low-pressure useful power turbine 17 which discharges through the recuperator 13a, 13b and cooler 20a, 20b to the intake of the compressor 10. The heater 14 may be in the form of a heat exchanger wherein the working gas is heated by a liquid coolant such as the liquid sodium from a nuclear reactor, or the heater may be a nuclear reactor in which the working gas e.g. helium or air is used as a coolant. A by-pass controlled by a valve 22 is provided round the turbine 17. An accumulator 23 containing a receiver drum 24 is also provided. The drum 24 is connected to the accumulator 23 by a motor-driven positive displacement pump. The drum 24 is connected to the discharge of the compressor 12 through a conduit 27 containing a control valve 28. The accumulator 23 is connected by the conduit 29 containing a control valve 30 with the conduit 68 connecting the recuperator 13 with the heater 14 and by the conduit 31 containing the control valve 32 with the intake of the compressor 10. During normal running the valves 22, 28, 30, 32 are closed so that the compressor 10 sucks working fluid from the interior of the upper part of the casing 35 and discharges it through the duct 38 and intercooler 11 to the intake of the compressor 12 which discharges through the recuperator 13 formed in two parts 13a, 13b to the heater 14. The outlet from the heater 14 is connected through a duct 46 with the inlet of the high-pressure turbine 15 driving the compressors 10, 12, the exhaust of which passes through a duct 15b to the useful power turbine 17. The exhaust of the useful power turbine 17 passes through a space 75 and upwardly through the recuperators 13a, 13b and cooler 20a, 20b back to the space from which the compressor 10 inhales air. The compressor 10, 12 and turbine 15 are enclosed in a casing 37 secured to the casing 35 by bolts 40 engaging flanges on the ducts 38, 39. The inlet manifold 59 of the recuperators 13a, 13b is connected to the casing 37 by links 60 and duct 58. The outlet manifold 63 is supported by pillars 69 from the casing 35 to which it is connected by a duct 64. Lateral lugs 70 on the recuperators engage notched brackets 71 secured in the casing 35. Connectors 72 allow for misalignment of the sections of the recuperators. The casing 37 projects through an internal wall 50 which defines a chamber 51 between itself and the closure plate 36. The downstream end of the casing 37 encloses a part of an elbow pipe 48 and is connected to the wall 50 by flexible bellows 49. The elbow pipe is in open connection with the chamber 51 through ports 52. The turbine 17 discharges into a space 75 formed by liner 73, side walls 73a and a wall 74 level with the lower ends of the recuperators 13a, 13b. During idling, the valves 32, 34 are closed and valves 22, 28, 30 are open. The working fluid then flows through the low-pressure compressor 10, the intercooler 11, the high-pressure compressor 12, the receiver drum 24 and transfer pump to the accumulator 23 from whence it passes through the heater 14 and compressor driving turbine 15, through the power turbine by-pass, recuperator 13 and precooler 20 back to the inlet of the compressor 10. When power is being increased the valves 22, 28, 30 and 34 are closed and valve 32 open so that in addition to the working gas flowing in the closed circuit as for normal running, further gas is fed into the circuit at the intake of the compressor 10 from the accumulator 23. On reduction of power, valves 22, 30, 32, 34 are closed and valve 22 is open so that in addition to the working gas flowing in the circuit as for normal running, working gas is tapped off from the delivery of the high-pressure compressor and conveyed to the receiver drum 24 and accumulator 23. On emergency shut down, valves 22, 28, 30 and 34 are open and valve 32 closed, so that part of the discharge of the high-pressure compressor flows back to the inlet of the low-pressure compressor and part to the receiver drum 24 and accumulator 23 from which it passes through the heater 14, compressor driving turbine 15, power turbine by-pass, recuperator 13 and precooler back to the inlet of the low-pressure compressor.