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Previous Next The best candle and soap tips online! TECHNICAL TREATISE ON SOAP AND CANDLES. MATERIALS USED IN THE MANTJFACTCRE OP SOAPS. 83 which a tin pipe was iixed and carried under the grate of one of the boilers over an open. fire. The contents of one of the melting coops consisted of raw tallow, of first and second qualities, mixed with the required amount of diluted sulphuric acid. The fire under the boiler close by burnt briskly when the steam was admitted into the melting vat. As the vapors developed therein, it was found that they were drawn off completely through the tin pipe which had been placed upon the cover, and streamed towards the fire; they passed freely through the grate, the fireplace, and the chimney. But it very soon became manifest that they extinguished the fire, which before the commencement of the steam development burned very brightly. The admission of steam into the melting vat was now interrupted, the fire was again started afresh and the steam readmitted, and the same observation made for a second and a third time, viz., that the fire was extinguished. The experiment of drawing the vapors under the grate of a fireplace, and there to burn them, gave according to this trial no favorable result. A second experiment was made in this manner: the tin pipe which was intended to carry the vapors from the melting vat was made to discharge itself into the fireplace. The vapors were easily drawn from the melting vat into the flames, did not extinguish the fire, and did not have the least smell at the opening of the chimney, and thus the fetid smelling products had been destroyed. This mode of wet melting, where the melting vessel can be supplied with a well fitting cover and the stirring of the contents does not become neceaaary, can be highly recommended. Fora permanent apparatus of thia kind a cast-iron inlet pipe would answer the purpose best, and should be immured in the side wall of the fireplace about 6 centimetres (2.3o inches) above the grate, right into the flame where this iron pipe might be placed, while outside the wall a tin pipe might Berve. By a third experiment the tin pipe for carrying off the vapors was brought into immediate connection with the chimney of the boiler fire. Here too the success was complete ; the vapors passed off entirely, and no particular smell could be noticed from the chimney opening. That tins manner of carrying off the vapors operates m a high chimney better than in a low chimney is self-evident. Even if it should happen that in foul weather the smoke of the chimney with the impregnated vapors should be pressed down into the streets, the spreading of a bad smell would not be so great as if the vapors were dispersed from the me It ing-room. A further experiment was made by which tallow was melted over an open lire, and where otherwise the well fitting wooden cover of the melting kettle was supplied with an opening for the stirring paddle; in order immediately to draw the vapors off and admit them into the fireplace and there to bam them up, but this operation led to no practical result. The vapors drew off but slowly into the fire, and escaped when the opening for stirring was not closed, or rather through it and the cracks between the rim of the cover and the kettle, instead of making their escape through the pipe. This arrangement would only be applicable when the cover closes perfectly and an opening for the paddle either could be entirely dispensed with, or a steam-tight paddle could be used. This experiment, changed in such a manner that the vapors which develop during the melting over an open fire were carried oft" by means of a pipe through the chimney, furnished a satisfactory result. The vapors vanished so readily that the opening for the paddle might be left open during the entire period of melting without the least escape of vapors or fetid gases. According to the above-described experiments we would recommend, as the most suitable and convenient of all the means thus far known, the carrying off of the vapors and odoriferous matters which form and develop in theoperation of either wet or dry melting1, by steam or over an open fire, by the application of a pipe to the chimney of a fire after it is started. Where the dry melting is preferred, the cover must be made of strong plate-iron and be provided with a slit for the paddle. For the purpose of scooping out the melted tallow, the cover must furthermore consist of two parts which are joined by hingea. Only in rare cases, by reason of inclement weather, may it happen that the vapors 8-1 TECHNICAL TREATISE ON SOAP AND CANDLES. wtjich thus stream through the chimney opening descend into the street and become noticeable. The facts reported by Grodhaus and Fink we can confirm l>y our own experience; we will uot fail, however, to draw attention to the fact, that (he chimney used for the carrying off of vapors must be built of well burned bricks, otherwise in its higher parts where a condensation of water takes place it will gradually become soft and be destroyed. According to the same method and based on the same principle the melting of tallow is performed in England, with thie exception, that the vapors are not, as in the process of Grodhaus nnd Fink, tarried immediately into the chimney, but are admitted into a wide pipe which is carried into the fire. The absorption here is so strong that not only all vapors out of the melting kettle, but also a certain quantity of air is drawn in with it, and the admission of the vapors will be noticed at the opening of every developing pipe. The combustion cueurs in the mouth of the pipe, and the gases reach the chimney almost entirely disinfected. In other establish men ta at Manchester, the vapors are led through a coke oven. In the large soap manufactories of Cowan & Son, twenty square kettles for the preparation of the fat are placed along the wall; every kettle has two openings, of which one opens outside and admits air, while the other is in connection with the ash-pit in which the draught may be regulated according to desire. AH kettles communicate with a horizontal pipe which carries the vapors under a particular fireplace. Among Ihe many new inventionafor rendering tallow, etc., in a manner to ayoid the offensive odors arising from (he operation, that invented by Vohl is perhaps the most successful. The kettles are provided with covers through which the gases are conducted and consumed. Figure 1 represents this apparatus. A is the cast-iron cauldron, lined with sheet lead, and has a riddled bottom id ,- a is a tap to draw off the waste water; b is the tap through which ihe fat is drawn ; p is the fire-grate; B is the door for filling; c the cover, with a mica plate S 8; in the door ie also a mica plate T for viewing the interior. MATERIALS USED IN THE MANUFACTURE OF SOAPS. 85 D is the vessel into which the gases pass by the tibe w; v is a cover with sand joints r r; powdered lime is placed in D on oblique shutes to absorb the offensive gases. Any liquids condensed flow off through the pipe h, and the gases and Fig. 1 Previous Next
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