514 



HYDRAULICS AND ITS APPLICATIONS 



sliding axially and receiving its motion from two draw-bars which carr 



racks gearing with pinions whic] 

 are actuated either by an ante 

 matic governor or by hand (Figs 

 228 and 242). 



As thus constructed the tur 

 bine is capable of a full-load effi 

 ciency of about 82 per cent., fal 

 ing to about 65 per cent, at hal 

 gate. 



In the Hercules turbine th 

 wheel vanes are provided with 

 series of horizontal wings or prc 

 jections, which to some exten 

 serve the purpose of separate com 

 partments in confining the effec 

 of throttling to one portion of th 

 wheel and thus increasing th 

 part-gate efficiency, at the es 

 pense, however, of that at fui 

 gate. 



Fig. 245 shows the genera 

 arrangement of a vertical Nei 

 American turbine, in which th 

 admission of water is controlle 

 by the wicket gates G. Thes 

 are operated through a rin 

 which is moved by a link cor 

 nected with the governor throng 

 the shaft S. 



Fig. 246 illustrates the San 

 son-Leffel turbine, which cor 

 bines a radial inflow runner j 

 the Francis type with an inwa j 

 radial admission and axial di 

 charge runner of the typicj 



American type of turbine. Ht j 



FIG. 246. Samson- Leffel Turbine. . , , . , , . , . 



again the gates are of the wicl I 



type and are operated from the governor through the pinion P and gear I 

 sector S. 



