494 



HYDKAULICS AND ITS APPLICATIONS 



square inch is supplied to the annular chamber C surrounding the 

 bush B, and escapes outwards between the fixed and rotating discs at Z). 



These discs have an outside diameter 

 of 36 inches and a bearing area of 

 about 780 square inches, the upper 

 thus floating on a film of oil and 

 giving a very frictionless bearing. 

 The hollowed screwed spindle S is 

 14" outside and 8j" inside diameter, 

 and is provided with two locknuts 

 at N, by means of which the turbine 

 shaft may be adjusted vertically. 

 Any slight swing or lateral wear of 

 the shaft is permitted by the spheri- 

 cal bearing surface of the lower 

 disc. 



Speed regulation is performed by 

 a centrifugal governor (Fig. 234E), 

 operating a regulating valve which 

 regulates the supply of oil (main- 

 tained at a pressure of 1,120 Ibs. per 

 square inch) to the upper side of a 

 relay cylinder C, the downward pres- 

 sure on this piston overbalancing 

 the weight of the gate mechanism 

 and thus operating the cylindrical 

 speed gates. Adjustment of the 

 speed while the turbines are running 

 may be performed by the hand regu- 

 lating wheel H. 



The turbine runners have a di- 

 ameter of 64 inches and a blade 

 depth of 11 '8 inches, while each 

 carries twenty-one vanes. The 

 guide vanes are twenty-two in num- 

 ber. The tail-race which takes the 

 discharge from the whole battery 

 of turbines is 2,590 feet in length, 

 and has a gradient of 7 in 100, being designed to discharge, at full load, 

 8,800 cubic feet of water per second, As the sectional area of the tail- 



GFeet. 



Scale oF Lengths. 



FIG. 234D. Main Footstep Bearing for 



10,250 H.P. Turbine. 



