T UR HINES.
While the use of the water-wheel, whose inventor is unknown, can be traced back to a period before the Christian era, the turbine, though for several centuries known and employed in sonic imperfect form of construc tion, belongs to the present century. Its development, which was based somewhat on theories, from its crude primitiveness into a construction that could stand the test of perfected technical knowledge, and its intro duction into a wider sphere of usefulness, however, date only from Seg ner's invention in 174o, and from the mode of construction proposed by Euler in 1754.
Turbines (from turbo, turbinis, a top or whirl), also known as vortex wheels, utilize water-power by the effect of the impact of the water, and in addition to this by its reaction, and never, as with the water-wheel, directly by weight. Like water-wheels, however, turbines consist of wheels provided with paddles or buckets, and shafts for guiding their rotation and for transmitting- their power to a convenient place for its application; and while the water-wheels permit the moving water to escape at the side on which it is received, in the turbines it passes through and escapes on the opposite side. Turbines were originally constructed only with vertical shafts and horizontal wheels. They were called " hori zontal " water-wheels, in contradistinction to the hydraulic motors illus trated on Plates 62 and 63, which were termed " vertical " water-wheels. Since, however, turbines with horizontal shafts and vertical wheels have for some time been constructed—as, for example, Figure 3 ( /V. 68)—this des ignation is no longer correct. Turbines are classed as outward-flow, inward flow, and parallel- or downward-flow wheels, according to the direction taken by the water in passing through them. The turbine was introduced into general use by Fourneyron in France in 1827, and soon after by Fairbairn in Englaird and by Boyden, Parker, Swain, and others in America. The varieties of turbines at present in operation throughout the United States are numerous, covering, perhaps, every known form, mode of action, and direction of water-flow through them.
The development of the two principal types of turbines now in use is based on the inventions of Segner and Euler, and doubtless the perfection of a third type, which as regards external appearance and mode of action is an outgrowth from the older constructions, is due to the zeal for improve ment aroused by these two inventions, which are based on the principle of hydraulic reaction. This phenomenon of the reaction of flowing water,
first observed, as is generally supposed, by Bernoulli in 173o, is exempli fied in the Barker mill ( /V. 3, As,r. 6), which consists of a vertical vessel or tube provided with horizontal discharge-pipes, which receive by the out flow of the water a pressure in a direction opposite to the outflowing jet. (See p. 37.) The first one to apply the double sources of power, impact and reaction, to turbines was Fourneyron.
Scgner's Reaction Tzirbinc.—Segner combined the tube with a vertical shaft which could be freely turned on a pivot, and its rotation was effected by placing the aperture of the discharge-pipe at a point farthest from the shaft and in such a manner that the jet flowed out tangentially to the circles described around the shaft. In another construction, employed for driving a flour-mill in Norten, near Gottingen, he provided the lower por tion of a tall vessel secured to a vertical shaft with four radial tubes, each of which contained a discharge aperture, whereby the reactive force of the issuing jets of water rotated the tubes with the vessel and vertical shaft.
Scoilish allied to the preceding, but of a later and more elaborate construction, is the Scottish or Whitelaw turbine (p1. 65, fig. 1), which, however, originated with Mannoury d'Ectot (1807). It consists of an S-shaped tube (A) somewhat expanded in the centre, and connected with the vertical shaft by means of vertical rods. From below and into this central expansion of the S-tube (A) enters a close-fitting pipe (D), which introduces the water from a reservoir placed at a higher level. The tangential discharge of the water from both ends of the S-shaped tube rotates the wheel and shaft by the effect of the above-described reaction. The shaft is suspended from a spindle-block, which, to decrease frictional resistance, runs on rollers. By arranging several such S-shaped tubes and enlarging the central expansion, and at the same time abandoning the complete tangential outflow, there is formed a wheel-shaped body, which, being closely set with tubes, forms the transition to the early form of tur bine, which consisted of two horizontal rims with vertically-curved vanes between them. Cadiat's turbine combines a wheel such as is above de scribed, but which is so far imperfect that it allows the water only to flow in with a loss of impulsive force.