CALENDERING. The operation by which all accidental wrinkles and creases are removed from various kinds of cloths, and their surfaces rendered smooth and uniform previous to packing for transport: calicoes are likewise calendered before printing. The common calendering machine nearly resembles the ordinary mangle, but worked by a horse-wheel, on account of its greater dimensions and weight ; but the more improved machines consist of a series of rollers, between which the cloth passes, the rollers being subjected to heavy pressure, and turning simultaneously either by simple contact, or by means of wheel work. Machines on this principle we believe are of foreign invention, but have received two important improvements in this country ; first, by the introduction of tubular cast iron rollers, into which heaters can be inserted when requisite, which greatly assists the operation with some kind of goods ; and secondly, in the substitution of rollers formed of pasteboard for wooden rollers, the former not being liable to crack or warp like the latter, and being susceptible also of an astonishing degree of polish. These paper or pasteboard rollers are formed as follows : the axis or shaft is formed of a square bar of wrought hen, turned cylindrical at the bearings ; a circular iron plate, of the exert sizs of the intended roller, is placed upon the square part of the shaft, and near to tile end, and a great number of discs of pasteboard, somewhat larger than the intended roller, and having square holes in the centre, are next put upon the shaft, and then another iron plate, and the whole are screwed together by nuts at the ends of four long iron bolts extending from one iron plate to the other. In this manner a cylinder is formed, considerably longer than the intended cylinder; this is removed to a stove or hot room, and as the paper shrinks by the heat, the plates are gradually screwed up. When, at the end of some days, the paper ceases to shrink, the cylinder is removed from the stove, and becoming exposed to the humidity of the atmosphere, it has a tendency to expand, and becomes exceedingly dense and solid, and is completed by turning in a lathe to the intended size. Some goods are required to have a high polish, called glazing.
upon one side ; this glazing was formerly effected by rubbing the cloth with a smooth flint stone, but is now generally performed in the calendering machine, by an addition of wheels, which causes one of the rollers to move slower than the rest, and the cloth consequently rubbing over the polished surface of the slowest mover, becomes glazed. a a Fig.1, are two paper rollers, each of 20 inches diameter; b b two hollow cast iron cylinders, 8 inches diameter, and 2 inches thick, the exteriors of which are turned perfectly smooth ; c a paper roller, 14 inches diameter ; d d the framing of cast iron, containing the bushes or bearings, in which the journals of the rollers revolve ; these are firmly pressed together whilst the cloth is passing through, by means of weighted levers. Fig. 2 is an end view of the same calender, with the wheels for glazing the cloth ; the wheel on the upper cylinder b is 10 inches diameter, that on the under cylinder b is 13 inches diameter, and both are connected by the wheel f ; so that the wheel on the under cylinder being nearly one-third more in diameter than that on the upper cylinder, the difference of their motions retards tho centre paper roller, by which means the upper cylinder passes over the cloth one•third quicker than the cloth passes through the calender, and polishes it in consequence. For dressing muslin., gauzes, and other light, transparent fabrics, a smaller species of calender is employed. It consists of only three cylinders, of equal diameters, (generally about 6 inches,) and is easily moved by a common winch or handle. The middle cylinder is of iron ; they are all moved with equal velocities by small wheels. This machine is always used in a cold state. Calendering forms one part of the business of a packer ; iii the subsequent stages the goods are folded into certain forms, depending upon the nature of them, and the markets for which they are intended ; they are then subjected to the action of a very powerfid press, and whilst under pressure are corded, so that when removed from the press they occupy much less room than they otherwise would do.