482 



HYDRAULICS AND ITS APPLICATIONS 



In either case a thrust bearing must be provided to take care of any 

 unbalanced pressure. This consists either of an ordinary submerged 

 step bearing with the shaft running in a lignum-vitse bush, or preferably 

 of a suspension bearing placed above tail- water level. The latter method 

 provides obvious advantages in the way of accessibility, ease of examina- 

 tion, and freedom from grit, and enables forced lubrication to be applied. 

 One type of suspension bearing is illustrated in Fig. 225. 1 Here the turbine 



wheel is keyed to a hollow shaft which 

 terminates at its upper end in the lantern 

 A. This lantern is connected by the 

 feather key D to the steel shaft (7, which 

 is fitted with a lock-nut E, by which the 

 vertical adjustment of the wheel may be 

 altered. 



A gun-metal washer F works between 

 fcae hardened steel discs G and H, of which 

 G is rigidly fixed to the bottom of the 

 shaft C, and H to the oil cup J, which in 

 its turn is cottered on to the shaft K. 

 This latter shaft is continued downwards 

 and is firmly fixed in a cast-iron socket 

 on the tail-race floor. The bottom end 

 of the shaft C is prevented from moving 

 laterally by the gun-metal bush 0, and a 

 series of radial grooves on each face of the 

 washer F enable oil to reach every part of 

 the bearing surfaces. 



The comparative ease of regulation 

 by cylindrical gates, together with the 

 large passage areas possible with the 



axial flow type of wheel, led to the design, for fairly large powers undei 

 low heads, of the cone turbine. 



Here, as indicated in the sketch (Fig. 226), 2 the flow is diagonal from 

 the entrance to the exit from the wheel, and the turbine becomes inter- 

 me liate between the inward radial and the axial flow type. As shown 

 the wheel may be subdivided into several complete wheels of different 

 diameters, each of which may be regulated by a cylindrical gate. This 



FIG. 225. Suspension Bearing for 

 Vertical Turbine Shaft. 



1 By kind permission of Messrs. Gilbert Gilkes & Co., Ltd.. Kendal. 

 8 By permission of Messrs. Escher, Wyss & Cie., Zurich. 



