Patent GB-190611858-A (GB)
Title: Improvements in and relating to Governing Mechanism for Elastic Fluid Turbines.
Filed: 1906-05-21
Granted: 1907-05-21
Abstract: 11,858. Warwick Machinery Co., [General Electric Co.]. May 21. Elastic-fluid turbines. - Relates to governing- mechanism for elastic-fluid turbines wherein the valves are successively opened or closed in response to load changes. In the example described, five valves are used, but the number may be varied. The admission of motive fluid to the turbine is controlled by a series of valves 5, Fig. 1, enclosed in a suitable steam-chest. Sections of the mechanism contained in the casing 15, Fig. 1, are shown in Figs. 3 and 5, and views of portions of the mechanism are shown in Figs. 6 and 7. Each valve is provided with a stem made up of two parts 40, 41, Figs. 1, 5, and' 6, connected together by a slotted coupling 42, Fig. 6, so that the outer portion of the stem can be lifted bodily without disturbing the valve and its attached stem. Within the casing 15 is a main rocking-shaft 45 and an auxiliary rocking-shaft 46. The shaft 45 is continually vibrated by a lever 17, driven off the turbine shaft through worm gearing, eccentric, and lever 18, as shown in Fig. 1. The motion of the shaft 45 is communicated to the shaft 46 by cranks and a connecting-rod. A slide 49, Figs. 3, 5, and 7, is mounted upon the shafts 45, 46, and is adapted to be slid parallel to the rocking-shafts by suitable linkage actuated by a governor mounted upon the turbine sbaft and enclosed in a casing 8, Fig. 1. The object in causing both shafts 45, 46 to rock is to overcome the static friction of the parts, A cross-head 55, Figs. 3, 5, and 6, is constantly reciprocated in a direction at right-angles to the direction of motion of the slide 49 by levers 56, 57, Fig. 6, actuated by the shaft 45. The valve stems pass through slots in the cross-head 55, but are not positively connected to it. For each valve, a centrally pivoted dng 52, Figs. 3 and 5, is carried by the cross-head 55 and reciprocates therewith. Each dog normally stands with one corner up and the other down as shown in Fig. 5. Trip springs prevent it from occupying the intermediate position. The corners of each dog engage shoulders 60, 61, Fig. 5, on the corresponding valve stem. When the dog is in the position shown in Fig. 5, the shoulder 60 is engaged, and as the dog reciprocates the valve is pushed to the left and remains there as long as the dog is tilted as shown. When the other corner of the dog is tipped up, it engages the shoulder 61 and closes the valve. The tilting of the dogs is performed by projections 50, 51 on the governor-controlled plate 49. When the turbine is working at full load, all the dogs are in the position shown in Fig. 5, and all the valves are open. The projections on the plate 49 are so arranged that, as the plate is moved laterally by the governor, the dogs are tilted successively and the valves closed. As a modification, the lateral distance between each pair of projections may be less than the width of a dog, so that at the critical point for each valve the dog will tilt for each reciprocation of the cross-head, thus causing the valve to pulsate. The construction of the centrifugal governor is shown in Fig. 8. Weights 67, 68 are pivoted on knife-edges 70 connected to a spring- controlled sliding piece 73. The spring may be adjusted by a screw 78. The spring is enclosed in a shell 79, secured in the recessed end of the turbine shaft. The movements of the slide 73 is transmitted by a rod 83 to the lever 9 by way of thrust ball bearings in a head 85. Suitable linkage, as previously stated, connects the lever 9 with the regulating-plate 49. A crank-disk 20, Fig. 1, which rocks the lever 18, also furnishes the power for driving the plunger 23 of the lubricating-pump, the letter being enclosed in a casing 25. A pressure-equalizing chamber 26 is connected to the pump. The casing 25 is filled with lubricant which is drawn into the pump through openings 34. Lubricant is forced into both end bearings and is returned to the chamber 25, suitable cocks being provided to regulate the supply. The method of lubricating the valve mechanism is as follows :-Lubricant in an oil cup 35, Fig. 1, drips into the tray formed in the upper part of the crossbead 55, Fig. 6, in which are lubricating-passages 90 leading to the valve stems. The excess lubricant flows over the surface of the stems and lubricates the dogs and pivots. Passages are also provided for the lubrication of the other moving parts. A drain pipe 36, Fig. 1, leads from the casing 15 to the main bearing. The lubricant is finally returned to the pump by a pipe 31.