CALENDER, a mechanical engine employed by cloth-lappere, for dressing and finishing cloths and stuffs of various descriptions and fabrics, before ex posure to sale, or delivery to purchasers. It is also used by calico-printers, in order to extend and smooth the surface of their cloths, after they have been bleached, and before they are subjected to the ope rations of the printing table or copperplate press.
In all cases two, and in many three, must be attained, in order to give to cloth that ap pearance which it is deemed necessary that it should possess, to attract the eye and gratify the fancy of the purchaser and consumer, The first of these requisites consists in as perfect extension and smoothness of surface as can be at tained ; so that no wrinkle or doubled folding may remain in it, excepting such as shall afterwards be intentionally made, in order to the reducing of it so the proper form and shape.
The second requisite acquired by the calendering of cloth, is the compression of the yarn or threads of which the texture is composed, which in some de gree divests them of their cylindrical shape, and re dukes them to a degree of flatness, which, by bring ing them more closely into contact with each other, gives to the fabric a greater appearance of closeness and strength, than it would otherwise possess. The operation of the calender also improves the, su perficial appearance, by flattening down all knots, lumps, and other imperfections, from which no mate rial, from which cloth is fabricated, can ever be entirely freed during the previous processes of spin ning and weaving.
And thirdly, in many fabrics it is desirable and esteemed a great addition to the effect and beauty of the • superficial, that cloth should re ceive, by means o friction and an application of bleached wax, an additional lustre or polish, which is generally distinguished by the appellation of glazing, and is chiefly required in those stuffs which are em ployed in the ornamental descriptions of female attire.
Such, in a strictly limited sense, are the sole and ex clusive effects resulting from the mechanical operation of the calender ; but, as other operations besides smoothing or glazing are necessary for the proper preparation of cloths for the market, these also are carried on by the same persons and in the same pre mises. Hence by a natural, although not strictly
correct, extension of its acceptation, the term ca lender, which really means only the chief mecha nical engine employed, gives the general name to the whole establishment where all the varied operations of cloth-lapping are carried on ; and it is as usual to say that goods are packed, as that goods are dress ed, at a calender. In the illustration, therefore, of those operations, which the limits of this article will admit, the first object will be to convey a distinct idea of the principles, construction, and operation of the principal machinery employed ; and then to add such general and miscellaneous observations as may serve to elucidate how the business of cloth lapping is carried on in its present extended form.
For the purpose of smoothing both surfaces of a' piece of cloth, it is necessary that they should be exposed to universal contact and pressure in every point, with some body of sufficient density to acquire the requisite degree of superficial polish. Such equality of surface, however, as will produce this effect, is not very easily attainable in large plane surfaces. Hence the contact of cylinders, in this operation, has been found to be in all respects in finitely preferable to that of planes, both in the speed and the effect of the operation. The common domestic smoothing iron is. the most simple of all calendering utensils ; but, even in the application of its small and limited surface,. in would be difficult to procure any table or board sufficiently to bring the whole cloth into equal contact with the iron, without the intervention of a few folds of blanket, or some other thick and soft woollen cloth.