Patent GB-1319034-A (GB)
Title: Closed cycle gas turbine systems
IPC: G21D1/02
Filed: 1971-01-22
Abstract: 1319034 Closed cycle gas turbine plants ENGLISH ELECTRIC CO Ltd 21 Jan 1972 [22 Jan 1971] 2975/71 Heading F1G The invention relates to a closed cycle gas turbine plant of the type having a separate power turbine, in which means are provided such that in the event of loss of load of the power turbine, a part of the gas passing to the power turbine is diverted so as to flow to the power turbine in a reverse direction so as to rapidly destroy the pressure drop across it, the remainder of the gas being passed to a cooling means. The plant shown comprises a compressor drive turbine 3 from which in normal operation gas passes to the separate power turbine 5 the gas from which flows through line 7, the valve 13 being open and the valves 12, 14 and 22 being closed. Upon loss of load, the valve 13 is closed and the valves 12 and 14 are opened so that the gas outlet from the power turbine is closed and gas from the compressor-drive turbine passes through duct 20 to the outlet side of the power turbine which is rapidly brought to rest. Gas discharging from the turbine 3 also passes through line 4 and the valve 12 to the cooler 18 finally rejoining the line 7 downstream of the valve 13. In the event of excess gas temperature at the inlet of the compressor-drive turbine 3, the valve 22 is opened and the gas flows through valves 22, 13, 14 and 12 to the cooler 18. A heat exchanger 8 is provided for pre-heating gas passing from the compressors 10, 11 to the heater 1 which is of the nuclear type. The apparatus is shown disposed in the wall of the nuclear reactor, gas passing through duct 29 to the compressor-drive turbine 3, the gas then passing through duct 31 to flow vertically upwardly through the power turbine 5. The gas discharges through a lateral duct and the open valve 13 to the duct 42, the exhaust gas then discharging through gas pre-heater 8. The valve 13 is of the poppet type comprising a stem 35 and a head 34, the stem being mounted in a sleeve 37 and being movable by linkage 38, 39; the valve 13 is combined with the valve 14 which comprises a cylindrical sleeve 44 co-operating with an annular port 48, the sleeve being connected with the valve head 34 by spokes 46. Upon loss of load the valve 13 is moved to the right to close off the outlet of the power turbine and the valve 14 moves simultaneously to open the annular port 48. The valve 12 also comprises a cylindrical sleeve 64 co-operating with an annular port 63 and simultaneously moves from the closed position shown to the open position. A portion of gas discharging from the turbine 3 now passes through the open valve 14 to the discharge side of the power turbine 5 whereby the turbine is rapidly brought to rest; the remaining portion of gas from the turbine 3 passes to the open valve 12 through the annular port 63 to the gas cooler 18 whereby the heat in the gas is dumped. The cooled gas passes through outlets 95 thence through duct 42 to the gas pre-heater 8. In the event of excess gas temperature at the inlet of turbine 3, the valve 22 is opened, so that gas bypasses the turbine 3 and passes through the open valves 14 and 12 to the gas cooler 18 the valve 13 being closed. The construction of the valves 13, 14 is shown in detail in Fig.3 and the construction of the valve 22 is shown in Fig.4; these Figures are not shown.