SOAP. —Boiling.
771
in diameter and 15 feet deep, and capable of yielding25 to 30 tons of soap at one operation. The pan orkettle is fixed in the brickwork, and so built roundthat the heat acts solely at the bottom. The wastelyes are withdrawn from the bottom by means of apipe fixed to the boiler. The pans are usually eastwith a flange at the upper rim, so that if necessarythe boiler may be enlarged by adjusting a hollowcone of wood, iron bound, and which is termed thecurb. It may extend as high as desired, and shouldbe surrounded with mason work like the rest of thepan. The boiling of the soap is accomplished bymeans of steam, either conducted directly into thematerials in the boiler, or when a high tempera-ture is not desirable, by applying the steam to theouter surface of the caldron. The application ofsteam is a method of communicating heat to the
caldrons far preferable to the old method of placingthe boiler directly in contact with the fire. Not onlyis there a great saying of fuel, but less attention,and consequently fewer hands are required, whilethe facility of arresting the operation at any desiredmoment is of great importance. In the annexedrepresentation (Fig. 1) are shown three caldrons,A, a, A, set in solid masonry, m. The main pipeor steam feeder, G, is attached by the cock, p, tothe boiler, w, which is stationary, and generallyplaced against the wall immediately above thekettles or caldrons. These latter are partly of ironand partly of wood, the upper portion or curb beingwood, well hooped round by iron rings, and thelower portion of cast iron, and so shaped that theworm can lie closely to the sides, and that the blow-pipe can fit upon the bottom. The steam is admitted
H tlj]
mmmmtsmmmmm
1 1 it
mm
to the vats by the cock, it, on the pipe, n. In thesection at k the position of the coil is displayed; thewaste steam is led away at x. The cock, i, is forthe withdrawal of the spent lyes. The pipe, l, serveswhen necessary to communicate additional heat tothe contents of the pan, and is useful also to agitatethe mass. In some manufactories the boiling vatsare made wholly of wood, well fastened by ironclamps.
Another arrangement of soap caldrons is shownin Fig. 2. a is the steam boiler; b b, the soap pans;C, the chimney; D, the steam chest, whence theserpentine coils, s s, are supplied with steam by thepipes, E E. The lyes are withdrawn from the panshy the cocks, 11 , and the condensed water from thecoils by the cocks, H h.
The process is rendered more rapid and fuel issaved by employing superheated steam. An in-
genious contrivance of Moefit’s for this purpose isshown on next page.
This apparatus (Fig. 3) is used for mixing, stirring,and heating, at one and the same time, the con-tents of vessels of any size or form, by superheatedsteam. It is well adapted for the manufacture of soap.a is the containing vessel, which may be a panwith a round bottom or a wooden tub. Firmlyfixed to the centre of the bottom of this vessel is aslightly conical metallic socket, communicating witha waste pipe, L; and adjusted to and turning inthis socket is the upright metallic shaft, C, carryingthe tubular arms or coils, db, ee, arranged in hori-zontal and vertical series alternately. There maybe two, four, or more of these series of branchingtubes. Each is tightly joined with the shaft at f,the centre of which is hollow from that point up-wards to the stuffing box, G, as a passage way for