| 摘要 |
979,392. Turbine and compressor blades. BROWN, BOVERI & CO. Ltd. Aug. 8, 1962 [Aug. 10, 1961], No. 30340/62. Heading FIT. Shrouded blading for turbines or compressors comprises a shroud having separate shroud plates attached to the blades, the blades displaying in the non-working and working conditions a torsional prestressing which presses the shroud plates of adjacent blades against one another in the circumferential direction. The shroud plates 2 are parallelogram shaped having edges of contact 4, 5 and surfaces of contact 6, 7 with adjacent plates. The blades have in the assembled condition a torsional prestressing which tends to twist them in a clockwise direction and increase the angle between the edges 4, 5 and the line 8 running parallel to the rotor axis so as to press adjacent shroud plates 2 together and damp oscillations. To compensate for thermal expansion the tangent of the angle is greater than the coefficient of friction between the surfaces of contact 6, 7. Surfaces 6, 7 may be treated to reduce friction. The invention is applicable to both stator and rotor blades. |
