TURBINE WHEEL 



TURBINE WHEEL 



in the turban of the grand vizier, and one in 

 those of other officers. 



During the first half of the nineteenth cen- 

 tury women in Europe and America wore a 

 modification of the Oriental turban, a custom 



TURBANS 



(a) Style worn by Christian priests in North- 

 western Asia; (&) Morocco turban; (c) Syrian; 

 (d) turban of citizen of Damascus. 



alluded to in Mrs. Gaskell's classic of village 

 life, Cranford: 



I was anxious to prevent her from disfiguring 

 her small, gentle, mousey face with a great Sara- 

 cen's-head turban. 



The gaudy headdresses worn by negro women 

 in the West Indies and the Southern United 

 States are also known as turbans. 



TURBINE WHEEL, or TURBINE, tur'bin. 

 The lawn sprinkler, which rotates by the re- 

 action of the air upon the water flowing through 

 holes in its arms, is the simplest type of a tur- 

 bine wheel. By enlarging the sprinkler and in- 

 creasing the pressure of the water a motor 

 might be obtained with sufficient power to run 

 a sewing machine or a coffee grinder, but the 

 waste of water would be so great as to render 

 the motor impracticable. A simple type of 

 turbine wheel, commonly known as a water 

 motor, consists of a small wheel with cups on 

 the outer ends of its spokes, and enclosed in an 

 iron case. A jet of water under high pressure 

 strikes against the cups and causes the wheel to 

 rotate. These motors are from twelve to four- 

 teen inches in diameter and are very successful 

 for operating machines that require but little 

 power. In principle ttey are reaction wheels. 



The larger turbine used in mills consists of an 



iron wheel with curved blades, or flanges, on its 

 surface, enclosed in an iron case to whose inner 

 surface blades similar to those on the whrt'l. 

 but curving in the opposite direction (see Fig. 

 1), are attached. 

 These turbines 

 may be placed in 

 a vertical or a 

 horizontal posi- 

 tion as conditions 

 require, but most 

 of them are hori- 

 zontal . The 

 wheel is placed 

 several feet lower 

 than the surface 



of the water to be , 



(a) Blades on the inner 

 used as a source surface of the case; (b) 



of power, and is blades on the wheel " 

 connected with the water supply by an iron 

 pipe called the penstock (see Fig. 2). When 

 the water is let into the penstock it flows 

 through a number of openings in the case 

 against the blades on the wheel, which is made 

 to revolve by the pressure of the water. 



Since the pressure of water is increased by its 

 depth, a wheel fifty feet below its source of 

 water supply will have twice the power of a 



FIG. 2 

 (a) Case; (6) wheel; (c) penstock. 



similar wheel twenty-five feet below the water. 

 Turbines of this type are known as pressure 

 turbines, and they utilize ninety per cent or 

 more of the power. Pressure turbines vary in 

 size from a few inches to eighteen feet in di- 



