Patent GB-191509570-A (GB)
Title: Improvements in and relating to Turbine Installations for Ship Propulsion.
Inventor: PARSONS CHARLES ALGERNON
IPC: F01D15/02
Filed: 1915-06-30
Abstract: 9570. Parsons, C. A., Walker, R. J., Cook, S. S., and Douglas, L. M. June 30. Plant; driving and transmission mechanism, special application of.-Relates to marine turbine installations of the kind described in Specification 20,366/14, wherein the ratio of the revolutions of a main turbine to the revolutions of the propeller it drives differs at low powers from the ratio at full power, and consists in utilizing at low powers supplementary gearing in conjunction with members of the transmission gearing normally used for full power. Of the single-shaft and twoshaft installations described, four examples are shown. The propeller shaft c, Fig. 1, can be connected by means of the clutch h, either to the low-power gear-wheel e, or to the full-power gear-wheel d, which may be permanently connected to the shaft of the low-pressure turbine b. On the shaft l of the high-pressure turbine a are mounted two pinions f, g engaging the wheels d, e and having a clutch k between them. The turbines a, b work in series, and the clutches h, k are moved so that, for full power, the turbine b drives the shaft c directly and the turbine a drives the shaft c through the pinion f and wheel d, while for low powers, the turbine a drives through the pinion g and wheel e and the turbine b drives through the train d, f, g, e in series. A cruising-stage may be fitted to the turbine a, or a cruising-turbine may be geared to the pinion f or to the wheel e direct, and adapted to exhaust into either the low-pressure or highpressure turbine. The low-pressure turbine b may be geared to the pinion d. An installation with a geared intermediate-pressure turbine is also described. In another modification, Fig. 5, the wheels d, e, which can alternatively be clutched to the propeller shaft c, mesh with the pinions f, g of the high-pressure turbine a, with the pinions q, q<1> of the low-pressure turbine b, and with the pinions u, v of an additional shaft s. By suitable operation of the clutches, four speed ratios are available, the gearing f, d and q, d being employed for full power, the gearing g, e and q, d, f, g, e for lowest powers, the gearing f, d, u, v, e and q, d, u, v c for lower intermediate powers, and the gearing f, d, q, q<1>, e and q<1>, e for higher intermediate powers. In a further modification, Fig. 7, the pinions v<1>, u' on the additional shaft s<1> mesh with pinions e', x, which can be respectively clutched for low powers to the propeller shaft c and the shaft c' of the wheel d', to which the turbines a, bare geared, while for high powers the shaft c is clutched directly to the shaft c<1>. In a two-shaft installation, Fig. 10, one propeller shaft c is provided with turbines a, b and gearing d, e, f, g, as in the first form Fig. 1, while the other shaft c<2> is provided with a coaxial low-pressure turbine b<2> and a high-pressure turbine a<2> connected through gearing f<2>, d<2>. A cruising turbine m drives the shaft of the pinion f<2> through gearing n, y. For full power, steam is admitted by conduits 1 to both turbines a, a<2>, which exhaust by conduits 2 into the turbines b, b<2>, the propeller shafts being driven directly by the turbines b, b<2> and through single reduction gearing by the turbines a, a<2>. Under cruising conditions, steam is admitted by the conduit 3 to the turbine m, which exhausts through the conduit 4 into the turbine b, while auxiliary exhaust steam led by conduit 5 to the turbine a exhausts also into the turbine b, the propeller shaft c<2> being driven by the turbine m operating through double reduction gearing, and the other shaft c being driven by its main turbines operating through supplementary gearing giving a different ratio from that obtaining under full-power conditions. Specification 20,082/14 is referred to in connexion with the steam flow of this installation, and several modifications of the gearing and of the crossconnexions for the steam are described. The full range of expansion may be maintained by using valves regulating the number of operative jets of certain of the initial stages where they are of the impulse type. Additional initial stages may be provided, and by-passes as described in Specification 7468/15; also initial stages of the partial-impingement type as described in Specifications 28,047/07, 17,872/08, 27,907/08, 28,373/08, 28,375/08, 28,376/08, 27,283/09, 29,119/09, 2295/10, 22,969/10, and 9005/15. In place of ordinary cruising-stages, coacting nozzle sections and reaction cruising-stages may be used as described in Specification 8980/11. The nozzles of all the impulse stages may be regulated simultaneously and proportionately by a single control member; mechanism of the kind described in Specification 20,366/14 may be used. Interlocking mechanism for the clutches and steam-supply valves may be used as described in Specification 804/13.