THOMSON TURBINE 



497 



This turbine may be constructed either as a double or single vortex 

 wheel. In the double wheel a series of vanes is fixed on either side of the 

 runner disc, which is keyed to the turbine shaft. Discharge takes place 



FIG. 235. Thomson Vortex Turbine. 



radially at the centre, and the water is then diverted axiaiiy through two 

 discharge pipes, or draught tubes, placed one on each side of the wheel. 

 This gives a wheel which is perfectly in balance as regards end thrust. To 

 facilitate the discharge, the wheel vanes are usually curved at their outlet 

 edges so as to direct the discharge water in the direction of the axis, 



