GB737648A - Improvements in gas turbine power plants - Google Patents

Abstract

737,648. Gas turbine plant. AKT.-GES. FUR TECHNISCHE STUDIEN. Dec. 2, 1953 [Jan. 13, 1953], No. 33535/53. Class 110 (3). In a gas turbine plant in which the working medium flows in a closed circuit including a heater, a turbine, a cooler and a compressor and the turbine has an inner and outer casing, working medium is taken from the circuit at a point where the temperature is lower and the pressure higher than the inlet temperature and pressure of the turbine and led through the space between the inner and outer casings to a labyrinth packing of the turbine where one part is directed towards the turbine rotor for cooling it and protecting the shaft from the hot working medium and the other part is expanded in a part of the labyrinth packing to a point of lower pressure. In the plant shown, working medium compressed in a compressor 6 is heated by the turbine exhaust in a heat exchanger 1 and then further heated in a heater 2 before expansion in a turbine 4. The turbine exhaust after passing through the heat exchanger 1 is cooled in a cooler 5 and then passed to the compressor 6. The turbine 4 comprises an outer housing 8 and an inner housing 10 separated by a space 9 which is connected by a duct 16 to a point 17 where the working medium is at a lower temperature and higher pressure than the working medium entering the turbine 4 at the inlet 11. The space 9 exhausts through a port 18 formed between the two parts 14, 15 of the labyrinth packing. A part of the cooler working medium flows through the part 14 of the packing towards the turbine rotor 12 to cool the rotor. The remainder of this working medium flows through the part 15 to a space 19 which is connected through a duct 20 with a point 21. The space 19 is sealed by labyrinth packing 22. If desired, the duct 20 and packing 22 may be dispensed with and the cooler working medium passing through the packing 15 passed to atmosphere. The outer housing 8 is maintained at such a temperature by the cooler working medium that it is capable of taking up the stress produced by the internal pressure. The outer housing 8 at the low pressure end is in direct contact with the exhaust working medium. As the temperature at the point 17 is substantially equal to the temperature, the entire outer casing is maintained at the exhaust temperature. A duct 24 connected to the compressor discharge may also be connected to the space 9. A valve 23 may be used to control the flow through the duct 24 and so control the temperature of the working medium flowing to the space 9. The space 9 may be connected at a plurality of points to the point 17.