FRANCIS TURBINE 



493 



Figs. 234 1 A, B, c, D and B, illustrate one of a series of double Francis 

 turbines installed (1903) in the power-house of the Canadian Niagara 

 Power Company. These are vertical shaft machines, each direct-coupled 

 to a generator and developing 10,250 H.P. at 250 revolutions under a 

 head of 133 feet. 



Power is transmitted through a tubular steel shaft 40 inches diameter 

 and '582 inch thick. The weight of the rotating parts is about 120 tons 



Balance 

 Chamber 



5 6Feet 



Scale of Lengths. 

 FIG. 234c. Section through Lower Runner and Balance Chamber of 10,250 H.P. Turbine. 



and is balanced, partly by the upward pressure on the bottom face of the 

 lower runner, water under the full pressure of the supply head being 

 admitted to a balance chamber (Fig. 234c), beneath this runner, and 

 partly by the upward pressure on the rotating balancing piston P 

 (Fig. 234s), which is mounted on the turbine shaft, and which is 

 exposed over its under side to the full pressure of the supply head. 

 Leakage past this piston is drained away to the tail -race, and by adjusting 

 the valve on the pipe S which supplies pressure water, the upward pressure 

 on the piston may be regulated with great nicety. Any unbalanced load 

 is supported by the suspension bearing (Fig. 234o), which is placed on 

 the upper deck. In this bearing, oil under a pressure of 375 Ibs. per 



1 By courtesy of Messrs. Escher, Wyss & Cie, 



