Blower

Pieces of apparatus for displacing air, usually at low pre ures. The term includes, 1: the fan or centrifugal blowers, in which a wheel with broad vanes or arms is made to Blast Engine. revolve rapidly inside a casing, so that the air between two arms is propelled radially by centrifugal force; 2, the rotary piston blowers, in which two parallel revolving shafts carry vanes of such shape that they are alternately sucking the air from outside the casing in which they revolve and forcing the air within the casing into the outlet; 3, the steam-jet blowers, blow acting on the Venturi principle of induced currents to draw the air, and to force it with a pre ure due to the velocity of the jet of steam. The air-compre or or blowing engine is not usually cla ed as a blower, inasmuch as it delivers small quan of air at high pre ures. See BLAST ENGINE.