Section 100.—HEATING APPARATUS.
For general purposes this comprises Furnaces, Stoves, Ranges, Ovens, Boilers (see [Section 6]), Hot-blast, Steam-heated Vessels, Gas Jets, &c., most of which are tolerably well known and in common use.
For special purposes in connection with machinery various heating devices are required, of which steam and gas are those most universally used. Steam tubes or coils may be carried through any fixed or movable part of a machine. Steam-heated surfaces, such as tables, pans, chambers, &c., steam-jacketed cylinders, and similar contrivances, are much used. Gas jets from perforated tubes, which may be shaped to any required position, are also convenient for dry heat and higher temperatures than can be obtained from steam.
Hot irons are sometimes used, shaped to fit a cavity, but of course require to be replaced periodically.
Hot water in pipes or jackets, and hot air in flues are common appliances for warming and drying; with the former its circulation must be provided for, and with the latter, either a forced draught or an upward inclination given to the flues to maintain circulation.
[1876]. Gill pipes for radiating the beat of steam or hot water.
[1877]. Gill stove, on similar principle, presents an extensive surface in contact with the air for radiation of heat.
Section 101.—DRAWING AND ROLLING METALS, &c.
[1878]. Rolls for bar iron, grooved to suit the section required, one-half the groove being usually in each roll, and the size and shape of the grooves are graduated down from that of the square billet to the finished bar.
[1879]. Grooved rolls for producing a tapered bar.
[1880]. Rollers for turning up and welding tubes from a flat strip.
[1881]. Bending rollers.
[1882]. Rolls for solid tyres, without a weld.
[1883]. Wire drawing apparatus.
For grips for drawing wire, &c., see Nos. [505], [518]. Laths of various sections are drawn through suitable steel dies by a draw bench; the end of the lath is held by a grip tongs and the lath drawn forcibly through the dies (using a lubricant) and afterwards straightened. Rolling does not answer for this kind of work.
The drawing frame used for cotton and other fibres has two, three, or more pairs of rollers; the lower rollers are grooved longitudinally and the upper ones weighted and covered with leather, the lower ones being geared together to drive at proportionate speeds, so that in passing through, the material is stretched between each pair of rollers, the object being to extend and lay all the fibres parallel.
For drawing lead pipes, see [No. 1183]. Earthenware pipes are made by a similar process.