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Home > and England their use is...
Previous Next The best candle and soap tips online! and England their use is more general. The first care to be taken in purchasing such a kettle, is to choose it without defects, and as thin as possible, for experience has shown that in this state it resists the action of fire better than when thicker. For the same reason soft cast iron must be preferred to hard. The first has a fine and soft grain, and can be more easily filed. It presents less inconvenience than the hard, brittle cast iron, and is capable of lasting much longer than the latter Indeed, a soft cast-iron kettle may last a very long time when well managed, besides, when warm, it requires very little fuel to keep up the heat. Sheet-iron Kettles.—These kettles are now generally used in nearly all the soap manufactories. Fora long time it was difficult to construct them, but since the progress in the mechanic arts, they have been constructed with great perfection. When a sheet-iron kettje is made, the dimensions must be calculated according to the quantity of soap to be manufactured. As we have said before, for every 100 lbs. of fatty matter, it requires a capacity of 37J gallons; starting from this base, the maker will always succeed in giving to the kettle the capacity necessary for the work for which it is intended. As for the thickness of the metal, it varies according to the capacity of the kettle. For a kettle of 750 to 1000 gallons, the iron should have 3 millimetres (0.11 inch) of thickness for the lateral sides, and 4 to 5 millimetres (0.15 to 0.19 inch) for the bottom. All the solidity of such a kettle depends entirely on the riveting; however, as well riveted as a kettle may be, it often happens that the first time it is used it allows a little liquid to escape, but soon the soap, by stopping all the crevices, completely prevents the leaking. Heating of Kettles by Fire.—In the heating of ordinary kettles by fire, the furnaces are constructed so as to absorb the most of the heat produced by the fuel, by applying at first the heat under the bottom of the kettle, and directing it afterwards around the sides, before losing it in the chimney. In soap kettles, on the contrary, a great part of the heat developed by the fuel is lost, because these kettles can 214 TECHNICAL TREATISE ON SOAP AND CANDLES. THE ESTABLISHMENT OF A SOAP FACTORY. 215 be heated only at the hottom, so as not to burn the soap, which would be the case if the heat circulated around the sides. Notwithstanding the imperfection of this kind of construction, and the enormous loss of fuel, experience has demonstrated that it cannot be modified without great inconvenience. To diminish as much as possible the loss of heat, it is necessary : 1. That the fireplace should be right in the central axis of the kettle. 2. That the lining of the hearth should be of refractory brick, in order that the heat may be thrown back below the bottom of the kettle. 3. That the fuel which produces the most intense heat with the least flame should be used; hence hard coal should be selected. 4. That the openings through which the products of the combustion enter the chimney should possess together the same surface as the grate, experience having shown that this Fig. 16. is the best arrangement for obtaining a good draft and effecting a complete combustion of the fuel. It is by fulfilling these conditions that the greatest amount of coal is utilized in heating the kettles. But to obtain this result, it is essential to have a well-constructed furnace, with all the recent improvements. The furnace must be very dry before using it. The figure (Fig. 16) represents a kettle heated by an open fire. The sides are composed of brickwork erected and lined with cement. The upper part/,/,/,/, which never comes in contact with the fire, and is intended to afford space for the soap to rise, expands in the form of a cone. The fireplace B, is separated from the ash-pit H, by the grate r. The fire, after having heated the bottom of the pan, passes by the flue t, t, t, half round the side of the pan into the chimney A. This is accessible for the purpose of cleaning by the door x ; the soot is thrown into the pit L. A tube with a cock leads from the lowest part of the pan for the removal of the spent lye. The whole of the pan is sunk into the floor of the boiling house, which is made of planks, stone, or iron plate, in such a manner that the brickwork of the upper part projects to about three feet above the floor. Heating of the Kettles by Steam.—-The most important invention introduced into the heating of the kettles, is incon-testably the heating by steam. For a long time numerous experiments were made, but it is only within ,about fifty years that this new system has been advantageously applied. The first manufacturers who used steam discharged it directly into the mass of the soap; the result was that the water produced by the condensation of the steam considerably lowered the degree of the lyes used to saponify the fatty bodies. They were then under the necessity of using more concentrated lyes. Soon after, other manufacturers — to obviate the above inconveniences—conceived the idea of causing the steam to circulate in the kettle, within a double casing, in such a manner that water produced by the condensation of the steam should not mix with the lyes, and weaken their degree. This sj^stem is still followed in some manufactories, but it has the inconvenience of heating the sides of the pan too much, and the bottom not enough. The result is that the ebullition is never very regular, and is 216 217 TECHNICAL TREATISE ON SOAP AND CANDLES. more pronounced on the sides than in the centre. Now, in new manufactories, pans with a double casing are suppressed, and the soap is heated directly by means of a flat worm of strong wrought iron, placed at about 3 to 4 inches from the bottom, and in which the steam circulates. This arrangement—as simple as it is ingenious, produces the best results, and the heating is so rapid that it requires only half an hour to boil a kettle containing 1000 pounds of soap, while the heating by an open fire will require from 3 to 4 hours. This advantage is not the only one this system presents; it enables us to heat with a single boiler, and consequently with the same furnace, several pans at a time, which presents a notable economy in fuel, time, and labor. There is no chance to burn the soap, as in heating with an open fire. The use of superheated steam presents greater advantages than those obtained by ordinary steam. Experience has shown that, by the use of "superheated steam, the operation is more rapid, and the expense in fuel greatly diminished. We give a representation of the whole arrangement, consisting of three caldrons, one for white, another for yellow, and a third for palm, and the finer soaps. G designates the main pipe or feeder, which is attached to the steam boiler W, of the establishment. It is stationary, and generally fitted against the wall, immediately above the kettles. The boiling caldrons are partly of iron and partly of wood—the upper portion or curb A being of wood, well hooped round by iron rings, and the lower portion D of cast iron, and so shaped that the worm may hug closely to the sides without loss of room, and the "blowpipe" fit snugly to the bottom. For the convenience of drawing off" the spent lyes, there are attached a pipe and cock I. Each of these kettles, resting upon a hollow pile of circular mason work M, is furnished with a welded wrought-iron worm, which connects with the main feeder at !N", and serves as the boiling medium of the soap paste. The steam is let on or off", by opening or shutting the cock H, and the waste steam is conducted through the other end of the worm X, which passes upward by the side of its inlet, and thence out in «,ny convenient way Previous Next
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