656 



HYDRAULICS AND ITS APPLICATIONS 



The general effect of the curvature, length, and dimensions of entrance of 

 the guide passages, and of the curvature and angle of delivery of the return 

 passages to the eye of the impeller, are shown in the curves of Fig. 324. 1 



Head and efficiency curves are given for four different designs of guide 

 and return passages, the same impeller of standard shrouded type being 



100 



200 300 



GALLONS, PER MINUTE '. \ 



B 

 iOOO 



FIG. 324. Effect of Guide and Return Passages of Different Form. 



used in each case. Design A has short guide vanes with wide opening 

 on the radial line. The return passages are of similar curvature. 

 Design B has similar guide vanes, hut the return passages have a shoi 

 curve becoming radial near the eye of the impeller. Design C also hi 

 similar guide vanes and the return passages are similar in curvatui 



1 Proc. Inst. Meek. Bug., 1912, No. 1, p. 18. 



