1044 



TURBINE 



with the guide-blades by means of links, cranks, &c. (see the figures), in such a way 

 that when the handle is moved, the four entrance orifices are all enlarged or contracted 

 alike. The gudgeons of the guide-blades, seen in fig. 2064, as small circles near the 

 points, are sunk in sockets in the floor and roof of the guide-blade chamber, and so 

 they do not in any way obstruct the flow of the water. M is the pivot-box of the upright 

 shaft, and is constructed with peculiar provisions for oiling the pivot, which, by reason 

 of its being under water, does not admit of being oiled by ordinary means. N is a 

 hanging bridge which forms the mixture of the pivot. 



This vortex is calculated for 50 horse-power, with a fall varying from 90 to 100 feet. 

 On account of the great height of the fall, the machine comes to be of very small 

 dimensions ; the diameter of the water-wheel itself being only about 15 inches, and 

 or . . . he extreme diameter of the case 



3 feet 9 inches. The speed for 

 which the wheel is calculated, in 

 accordance with its diameter and 

 the velocity of the water enter- 

 ing its chamber, is 768 revolu- 

 tions per minute. 



A low-pressure vortex con- 

 structed for another mill near 

 Belfast, is represented, in vertical 

 section and plan, in figs. 2066 

 and 2067. This is essentially 

 the same in principle as the 

 vortex already described, but it 

 differs in the material of which 

 the case is constructed, and in 

 the manner in which the water 

 is led to the guide-blade cham- 

 ber. In this the case is almost 

 entirely composed of wood. The 

 water flows with a free upper 

 surface w w, into this wooden Wise, which consists chiefly of two tanks A A, and B B, 

 one within the other. The water-wheel chamber, and the guide-blade chamber, are 

 situated in the open space between the bottom of the outer and that of the inner 

 tank, and will be readily distinguished by reference to the figures. The water of the 

 head race having been led all round the outer tank in the space, c c, flows inwards 

 over its edge, and passes downwards by the space D D, between the sides of the two 

 tanks. It then passes through the guide-blade chamber and the water-wheel, just in 

 the same way as was explained in respect to the high-pressure vortex already de- 

 scribed ; and in this one likewise it makes its exit by two central orifices, the one 

 discharging upwards and the other downwards. The part of the water which passes 



downwards flows away at onco 

 to the tail race, and that which 

 passes upwards into the space E, 

 within the innermost tank, finds 

 a free escape to the toil race 

 through boxes and other channels, 

 F and G, provided for that pur- 

 pose. The wheel is completely 

 submerged under the surface of 

 the water in the tail race, which 

 is represented at its ordinary 

 level at Y Y, fig. 2066, although 

 in floods it may rise to a much 

 greater height. The power of 

 the wheel is regulated in a simi- 

 lar manner to that already de- 

 scribed, in reference to the high- 

 pressure vortex. In this case, 

 however, as will be seen by the 

 figures, the guide-blades are not linked together, but each is provided with a hand- 

 wheel H, by which motion is communicated to itself alone. 



The foregoing descriptions are sufficient to explain the principal points in the 

 structural arrangements of these water-wheels. 



And now a few words more in respect to their principles may be added. In these 

 machines the velocity of the circumference of the wheel is mado the same as the 



