Patent GB-191510824-A (GB)
IPC: F01D15/02
Abstract: 10,824. Parsons, Sir C. A., Walker, R. J., Cook, S. S., and Douglas, L. M. July 26. Motor power plant; driving and transmission mechanism, special applications of.-Relates to marine motor installations of the type in which the ratio of the revolutions of a given motor to the revolutions of the propeller it drives differs at low powers from the ratio at full power, as described, for example, in Specifications 20,366/14 and 9570/15, and consists in arranging installations of this type so that a given motor drives a different propeller at low powers from that which it drives at full power. The installations may comprise two, three, or four propeller shafts and may employ single or double reduction gearing and a variety of crossconnexions between the turbine units, two examples being shown in Figs. 1 and 16. By means of the clutches 7, 11 the propeller shafts a, b, Fig. 1, are respectively clutched at high powers directly to the high and low pressure turbines 1, 2, through which the steam from a, conduit 3 passes in series. For low powers, the clutches 7, 11 are moved so that the turbines 1, 2 are declutched from the shafts a, b and the gearwheels 5, 10 are clutched to the shafts a, b, and by means of the clutches 8, 12, the turbines 1, 2 are clutched to the pinions 6, 9, which mesh with the wheels 10, 5. The turbine 1 then drives the shaft b, while the turbine 2 drives the shaft a. At low powers, the steam may be admitted by a conduit 14 to a cruising stage 13. In a modification, a cruising turbine is employed at low powers to drive one of the propeller shafts through single reduction gearing, while the other propeller shaft is driven through single reduction gearing by the low-presure turbine, which at full power drives the first propeller shaft direct. In other modifications employing pairs of turbines to each propeller shaft, single reduction gearing is used at full power, and double or single reduction gearing atlow powers. In an installation having three propeller shafts a, b, b<1>, Fig. 16, at full power the various clutches are so operated that the wing shafts b, b<1> are each driven through single reduction gearing 26, 24 by their high and low pressure turbines 1, 2, while the shaft a is driven through gearing 17, 57 by the cruising turbine 15, which develops a small power only and discharges into suitable stages of the high-pressure turbines 1. At low powers, the clutches are operated so that the wing shafts b, b<1> are idle, and the centre shaft a is driven by the cruising turbine 15 operating through single reduction gearing 17, 57, and by one high-pressure turbine 1 and one low-pressure turbine 2 each operating through double reduction gearing 26, 24, 58, 57. Means for operating the various clutches simultaneously may be provided, and also interlocking mechanism between the clutchoperating mechanism and the steam-supply valves, as described, for example, in Specification 804/13. Nozzle-regulating valves, and means for by-passing initial expansion stages, may be employed. The turbines may be replaced by other motors, such as electric motors, hydraulic transformers, reciprocating engines, &c.