SE319136B - - Google Patents

Abstract

1,138,607. Centrifugal pumps; hydraulic turbines. DOMINION ENG., WORKS Ltd. Feb. 23, 1966 [Feb. 25, 1965], No. 8170/65. Headings F1C and F1T In a hydraulic turbine, pump or pump-turbine in which fluid friction on the runner 14 is reduced by introducing a gas, such as air, through pipe 24 into an annular space 20 adjacent a shroud 17, a seal comprising an annular axial lip 37 extending from the shroud is provided at the radially outer portion of the space 20, the radially inner surface of the lip being formed so as to extend from the surface of the shroud and serving as a liquid-energizing surface within the space 20 for promoting toroidal circulation of sealing liquid and producing centrifugal separation between the liquid and gas adjacent the lip whereby a stable liquid-gas sealing interface is maintained in sealing relation with the space, and a portion 56 of the housing is provided adjacent the energizing surface with an annular surface which has radially within and axially overlaps the energizing surface so as to obstruct the flow of sealing liquid radially inwards from the seal. Similarly, an annular axial lip 38 is provided to form a seal for a aeration space 22 adjacent shroud 18, but a co-operating housing portion corresponding to the portion 56 is not provided since any water from the seal zone tends to drip off the housing and back into circulation with the sealing liquid. Leakage of air from the spaces 20, 22 towards the draft tube 15 is prevented by supplying water under pressure through pipes 33, 34 to annular seal spaces 26, 30 and to centrifugal separator flanges 29, 32. Further annular seal spaces 28, 31 are provided between the separator flanges 29, 32 and the spaces 20, 22.