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Previous Next The best candle and soap tips online! TECHNICAL TREATISE ON SOAP AND CANDLES. THE ESTABLISHMENT OF A SOAP FACTORY. 211 dry the soap, while with a much smaller expense of fuel a treble quantity of soap can be dried in eight or ten hours in a room heated by hot air. Fig. 15 presents a longitudinal section of a drying-room with hot air. A. Furnace in which the fuel is burned. B. Grate. C. Ash-pan. D. Door of the fireplace. E E. Cast-iron flue through which the fire and smoke pass to the chimney. F F. Chimney for the exit of the products of combustion. G. Register in the chimney, used to regulate the draft of the fire, and thus control the temperature of the hot air in the room. H H. Opening for the introduction of cold air; this air grows warm by circulating round the furnace A, and passes into the room by means of proper apertures. 111 I. Walls of the room which must have the thickness of a brick. KKK, Chimneys by which the air escapes, more or less saturated with the moisture of the room. L. Door by which the trays, full of soap, are introduced into the room. M M M M. Squares representing the pieces of soap to be dried. N .N". Vacant space between the trays and the bottom of the room. OOOO. Vent holes in the masonry which traverses the room in all its length, and which is provided with many openings to allow the hot air to pass into the room. P P P P P. Stone or brick foundation on which the room is built. The manner of using this drying-room is very simple. After filling the trays with pieces of soap, they are introduced into the room by the door L ; the door is closed, and the fire lighted. The cold air enters by the openings H H, grows warm by circulating around the furnace, and flows continually into the room by the openings 0 0 0. The temperature must not be too high but must be kept between 26.6° C. (80° F.) and 30° C. (86° F.). With an ordinary room, it is possible to dry 20,000 pounds of soap in a day. Kettles.—In our description of the necessary plan, the first item should be the kettles, which are of various kinds. Kettles are vessels in which, by means of heat, the manufacturer combines fatty bodies with lyes of potash or soda to form soap. Their dimensions vary according to the quantity needed. It is always advantageous to operate with large kettles, because they present a greater economy of labor, fuel, and lyes than the small ones. As for the capacity, we have ascertained that, for the treatment of every 100 pounds of fatty matter, we require a capacity of about 37J gallons, thus: to saponify 1000 pounds, a kettle of a capacity of 375 gallons ; for 2000 pounds, 750 gallons ; and for 3000 pounds, from 1000 to 1125 gallons, Avhich represents the ordinary size of the kettles of Marseilles. Whatever are their dimensions, these kettles have always a circular form, and gradually widen up to the top, so as to form a cone. Some have flat bottoms, others have convex or concave bottoms. Experience has shown that the latter arrangement is the best, and the most convenient for the work. Whatever is their capacity, they are always provided at their lower part with a pipe, with valve used to draw off, after each operation, the sub-lyes collected under the soap. Masonry Kettles.—At Marseilles nearly all the kettles of soap manufacturers are made of masonry, except the bottom, which is of copper or sheet iron. The most essential condition for the construction of such a kettle is to establish it on a good solid foundation. This foundation is covered with a thick mass of masonry, constructed of good materials, which is rendered tight with hydraulic mortar, a little soft, so that it may penetrate into all the interstices of the mass; by which means the infiltrations of liquid are rendered impossible. The kettle is afterwards built on this mass, beginning at the hearth and the surrounding walls, to which a thickness is given proportioned to the capacity of the kettle. When the level is reached on which the bottom of the kettle has to rest, it is 212 TECHNICAL TREATISE ON SOAP AND CANDLES. THE ESTABLISHMENT OF A SOAP FACTORY. 213 important to employ materials of the best quality, and the least apt to be destroyed by the action of heat and lyes. Some stones are not good for these kinds of construction, because the heat quickly injures them. Good stone must be used for the outside walls. As for the inside of the kettle, it is always formed of a thick counter wall, of hard and well-burned bricks, and of pozzuolana cement, employed with a certain quantity of fine sand. It is very important to fill all the interstices exactly, for, independently of the loss of material, they would have the effect of accelerating the destruction of the masonry. To preserve the kettle, it is surrounded outside with hoops of very thick iron. It is by these precautions that great solidity is given to these kettles. It is true, their construction is costly, and they require frequent repairs, but these inconveniences are well repaid by the advantages they present. The superiority attributed to these kettles over those made of metal, is generally recognized by the manufacturers of Marseilles, who use no others. Besides the advantage of better retaining the heat of the mass during the saponification, they are said to have that of not coloring the pastes, as is done by metal kettles. We do not know if there be any foundation for this assertion, but we can affirm that very white soaps are prepared in cast-iron or sheet-iron kettles; then, if the alteration of the whiteness and purity of the pastes were due to the use of metallic kettles, necessarily colored soaps would have been obtained, since these kettles were the only ones used ; but it is not so—it is sufficient to see fine white soaps manufactured in such kettles, to be assured that there is no foundation for the statement. The only condition to be observed, is to keep the kettles always cjean and dry, to prevent the formation of oxide of iron, which, by combining with the soap, would communicate to it a yellow coloration. Cast-iron Kettles.—Cast-iron kettles are not much used in soap manufactories, because they are more costly than those of sheet iron, and also, because it is very difficult to have them of a large capacity, made of a single piece. In France they are used only in small manufactories, but in Belgium Previous Next
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