| 摘要 |
994,537. Turbine blade mounting. BROWN, BOVERI & CO. Ltd. July 9, 1963 [July 11, 1962], No. 27110/63. Heading FIT. A method of fitting steam or gas turbine blades 3, having abutting parallellogram shaped tip shrouds 4 and fir-tree roots 1 in a circumferential channel in the rotor comprises introducing the roots of all but the last blade into the rotor channel and applying a twist to the blades 3 so as to reduce the space occupied by their shrouds 4 in the peripheral direction. The twist is applied to the blades 3 by a stirrup comprising a sector 9, offset screws 10 and an observation hole 13. Each pair of opposing screws 10 bears upon a wedge 11 mounted in a transverse groove in a temporary extension 4a of the shroud 4 of each blade 3 so as to exert a twisting movement upon the blade. Each stirrup covers about five blades 3 and successive segments of blades are acted on by a number of stirrups until all the fitted blades have been twisted to the required angle. The last blade is then fitted in the groove and divided spacing wedges 7 fitted between it and the roots 1 of adjacent blades and between the remaining blades. Wedges 11 are removed and shroud extensions 4a machined away. The construction effects vibration damping. |
