GB1270344A - Runners for axial water flow machines - Google Patents

Abstract

1,270,344. Mounting rotors of electrical machines. ENGLISH ELECTRIC CO. Ltd. 18 Sept., 1970 [19 Sept., 1969], No. 46223/69. Heading H2A. [Also in Division F1] A runner for an axial flow hydraulic turbine, pump or pump-turbine has the rotor of an electrical machine attached to the periphery of the runner vanes by resilient means arranged to permit relative radial movement. The resilient means may be stressed at assembly such that when the runner is stationary each vane is loaded compressively in a radial direction. In one arrangement, Fig. 2, the rotor 6 of an electrical generator carries poles 10 and is secured to the tip 20 of each vane of a turbine runner by a spring device 8. The latter comprises two stacks of conical spring washers 12, 14 separated by a flange 16 on a stud 18 screwed into the vane tip 20 and surrounded by a tubular housing 22 screwed to a flange 24À2 of rotor 6. The washers 12, 14 are thus held in compression and permit radial movement of rotor 6 relative to the vanes under thermal or centrifugal influence. Housing 22 may be filled with a damping liquid. Figs. 3 to 13 (not shown) illustrate arrangements which are basically similar to Fig. 2. In a further modification, Fig. 14, the generator rotor is secured to each vane by a stud 100 screwed into the vane tip. A bush 102 surrounds the stud and is bonded to a rubber or plastics cylinder 104 bonded in turn to a sleeve 106 fitted within a cylindrical housing 108 formed in the rotor. In a modification, Figs. 16, 17 (not shown), the bush 102 is replaced by a stack of rubber or plastics annuli, each annulus (110) being sandwiched between a collar (112) fixed to a central stud and a corresponding collar (114) fixed within a housing (116) formed in the rotor. In a further arrangement, Fig. 18, the generator rotor is formed in four circumferential segments and each segment is secured to the tip of a vane by an elastic beam 118. The latter is secured at its centre by bolts 124 to a pair of flanges 120 on the vane and is connected at both ends to the segment by bolts 122. In order to achieve an interference fit each bolt 122, 124 is tapered and surrounded by a split collar (126, Figs. 19 to 21, not shown) having a corresponding internal taper so that when the nut on the bolt is tightened the collar expands. In a modification, Figs. 22 to 25 (not shown), the beam (128) is secured in a different manner. The beam may be divided at the vane and the two halves cantilevered from the ends of the rotor segment to which they are attached. In any of the embodiments rubber or plastic packings (e.g. 96, 98, Figs. 12, 13, not shown) may be provided between adjacent radial faces of the vane tip and generator rotor to absorb torsional and axial forces. The runner may be disposed in a tube forming part of a tidal flow hydro-electric scheme.