Patent GB-190428131-A (GB)
Title: Improvements in Elastic Fluid Turbines.
Inventor: WILKINSON JAMES
Filed: 1904-12-22
Granted: 1905-04-20
Abstract: 28,131. Wilkinson, J. April 8, [date applied for under Patents Act, A.D. 1901]. Steam turbines.- Means are described for governing turbines of the impact and reaction types and enabling them to be worked efficiently when overloaded or underloaded. A larger number of supply nozzles are provided than are required for the normal load, and the additional nozzles are under the control of the governor, being fully opened for the maximum load and pulsated for loads between the maximum and the normal. Each nozzle is controlled by a valve 27, Fig. 2, which is opened and closed by a piston in a cylinder 31. The lower side of the piston is subjected to a pressure less than that of the supply or, if under the full steam pressure, is made o f smaller area than the upper. The upper end of each cylinder 31 can be subjected to the full steam pressure to close its valve, or can be exhausted to open its valve, by the means shown in Figs. 2 and 4. The normalload valves are controlled by alternate cylinders which communicate with an annular passage 51, and the overload valves are controlled by the other cylinders, which communicate with the similar passage 50. Steam is supplied to a chamber 44, Fig. 4, and is directed by a movable nozzle 46 into the passage 47, 50, or 51, as determined by the governor. In the position shown, the steam is supplied to the passage 50 and the corresponding cylinders and the overload valves are closed. At the same time, the passage 51 is exhausted and the normal-load valves are opened. Should the load increase to the maximum, the nozzle 46 is depressed to direct the steam into the passage 47 leading to the first stage, and the passage 50 is exhausted and the overload valves opened. Should the load be less than the maximum, the nozzle 46 is reciprocated in front of the passage 50 and the corresponding valves are pulsated. Similarly, the normal-load valves may be pulsated when the load decreases, and are finally closed when the load is below the minimum. The steam supply may be further adjusted by closing one or more of the normal-load valves or by reducing their lift by screwing down their stems 82 by hand. At the same time, a corresponding number of stage valves 35, Figs. 7 and 9, are closed by hand, their stems 38 having indicators 40 to show their positions. By means of a small hand-valve, live steam can be introduced into the passage 58 and thence into the lower ends of the cylinders 31 to open all the supply valves at starting. The nozzle 46 is pressed outwards by steam, and its position and movements to pulsate the supply valves are determined by a stepped cam 73, Figs. 5 and 6, which is mounted on the governor spindle. When the roller 72 on the nozzle spindle 49 is on the part 75 of the cam, all the supply valves are closed. When it is on the helical step 74, the normal-load valves are pulsated, and when it is on the cylindrical part 78 they are fully open. Should the load increase, the helical step 77 comes in contact with the roller, and the overload valves are pulsated. When the roller is on the cylindrical part 81, the overload valves are fully open.