500 



HYDRAULICS AND ITS APPLICATIONS 



The method of regulation by pivoted guides has many advantages. Of 

 these the following are the more important : 



(1) At all gates the guide passages are of a gradually convergent form 

 and offer easy curves to the supply water. 



(2) Water is admitted (with the spiral casing) evenly all around the 

 circumference. 



(3) The guide vanes are easily moved, and an easy and rapid regulation 

 of speed under sudden load variations is possible (specially important in 

 electric driving). 



(4) The guides may be arranged to give a small difference in the inclina- 

 tion of the stream entering the wheel buckets, together with a large 

 difference in flow, and therefore to give a constant speed with a constant 

 head and under a variable load, or may be so arranged as to give a greater 

 change in inclination of the guides with a medium change in the flow, 

 and thus to give a fairly constant speed under a variable head and variable 

 load. 



(5) The efficiency at part gate is high. The following test results have 

 been chosen as showing how the efficiency varies with gate opening in 

 this type of machine. 



1 By the Platt Iron Works, Dayton, Ohio, at the Quebec Railway Light .and Power 

 Company's Plant, Montmorency, Quebec. 

 a By Messrs. Escher, Wyss & Cie., at Sihl Paper Mill, Zurich. 

 8 By Messrs. Escher, Wyss & Cie., at Reutte, Austria. 



