Chapter VII: Section 7: Blowing and Exhausting

Some of the mechanical blowers are too well known to need illustration here; such are the ordinary Beam Blowing Engine, as in use for blast furnaces, Vertical Blowing Engine, and Horizontal Blowing Engine. In all these a cylinder and piston form the blowing device. Nearly every form of rotary engine (see Section 75) may, by reversal, be converted into a blowing machine. See Root’s patent, No. 1307; Baker’s, 1325, and others in common use. Fans, centrifugal, (see No. 1337) are still the commonest blowing machines, and are especially suited for light pressures and large volumes of air; but for pressures of from ¹⁄₂ lb. per square inch and upwards, the rotary or cylinder types are best. The following are devices not so well known, but sometimes useful:--

=101. The “Trompe,” or water-jet blower.= Water under pressure is discharged through a rose into a funnel-shaped inlet, carrying with it a quantity of air (see Section 45); the water runs off at an overflow, and the air is led away by a pipe.

=102. Steam-jet blower.= (See Section 45.)

=103. Organ bellows.= The lower “feeders” pump alternately into the double-tier upper “reservoir,” which has the upper set of ribs inverted, as shown, to equalise the pressure throughout its rise. The reservoir is loaded with weights to the required pressure.

=104. Smiths’ bellows,= either circular or hinged at one side.

The valves used for bellows are plain flap valves faced with leather
similar to No. 1619.

=105. Bell, or gasometer blower,= for light pressures and large volumes.

=106. Regulator, or reservoir,= for blowing engines to steady the blast. The weighted piston serves the same purpose as an air vessel to the ordinary pump.

=107. Disc blower,= with elastic diaphragm piston.

=108. One-crank three-throw blower,= for organs, &c., to give a continuous blast. The three feeders deliver into the central triangular box.