Abstract: A draft tube for a reaction turbine is formed of two gutter-shaped members of semi-circular transverse cross-section which are secured along their edges to a dividing plate. Flat guide plates are secured in the gutters to permit flattening the stream of water during its passage through the curved part of the draft tube.

Abstract: The present invention relates to a machining process especially suitable for facilitating the construction of large turbines wherein displaceable guide blades for directing fluid to the rotor have to be provided on the downstream side of the volute or spiral tank of the turbine. Hitherto the whole unit had to be machined and assembled in the workshop and then transported to site.

Abstract: A hydraulic installation includes a gate valve and an injector rectilinearly mounted in series in a water inlet conduit which feeds a turbine. The injector includes a central body portion in which first and second servo-motors are housed. The first servo-motor controls the tip of the injector and the second servo-motor controls the movement of the plug of the gate valve. A single crosspiece secures the injector to an outer annular casing and also absorbs hydraulic forces otherwise exerted on the gate valve and the injector.

Abstract: A valve shutter is fitted in a channel and is adapted to be shifted, between a valve-opening position and an intermediate position facing a seat provided in the valve body, through rotation around a transverse axis, while the channel is set under still water conditions. The actual fluidtight application of the valve shutter against its seat is ensured by the pressure of the upstream water when normal flow conditions are restored. This dual movement is possible due to the fact that the shutter supports or bearings are resiliently or pneumatically held in position with reference to the valve body.