GB190776A - Improvements in and relating to multiple unit steam turbine installations - Google Patents

Abstract

190,776. Parsons, Sir C. A., and Anderson, E. H. B. Sept. 21, 1921. Motor power plant. - In installations of the kind described in Specification 7468/15 two or more propeller shafts are each driven through gearing by two or more turbines in series. The turbine sets are connected by valve-controlled pipes so that while at high powers steam is supplied direct to the high pressure turbine of each set, at low powers steam is supplied only to some of the high pressure turbines and passes through the initial stages thereof, and then with the aid of the pipes passes in parallel through the final stages of all the turbines. In one form, two sets of turbines are employed in which the high pressure turbines 1, 2, Fig. 1, have initial stages 3, 4 and final stages 5, 6 respectively. Astern stages 7, 8 may be provided. Pipes 11, 12 lead to the low pressure turbines 9, 10 and in the case of astern running pipes 13, 14 are used. A pipe 19 connects the high pressure turbines and a valve 20 in the pipe is normally shut for high power running, steam being supplied at both inlets 15, 16. At low powers steam is supplied at only one of the inlets 15, 16 and the valve 20 is opened so that the steam after passing through one only of the initial stages 3, 4 divides and passes through the stages 5, 6 and the low pressure turbines. In another form, a diaphragm 21. Fig. 3, with labyrinth packing 22 separates the stages 4, 6 of the high pressure turbine 2 and two valves 20, 23 are provided in the pipe 19. At high powers the valve 20 is shut and the valve 23 open so that steam passes from the inlet through the stages 4, 6 in turn but at lower powers when the stage 4 is inoperative the valve 23 is shut and the valve 20 opened to admit steam to the stage 6 from another high pressure turbine. A single two-way valve may replace the two valves 20, 23. The inoperative stage 4 may be connected to the condenser or to some point of low pressure in the turbine to minimize rotational losses.