Page:Encyclopædia Britannica, Ninth Edition, v. 10.djvu/104

Rh 94 soluble in water, to obtain a strong amnioniacal liquor from the scrubber, and at the same time, as far as possible, to ‘*..:!W‘‘ H ,lII. I < Fl: '1, i' |l,;II| ‘ 1‘,J:'.‘,' ~ ‘. -. ." ‘i t I I Fig. 9.—Hislop’s Scrubber—éectional Elevation. prevent the heavy hydrocarbons from being acted on,—they being also soluble in water. The ordinary form of scrubber 5' DISCHARGE TO PUMP FROM FUN "= I2 6 n I_ 2 3 sc§_LI:_e,___5 -,, 9 »'‘‘Z—- ...a—_ _-'j..__**.-j Fig. 10.—Hislop's Se;ubber—Plan. consists of a tower or hollow column, vertically divided into two, and ﬁlled with coke, &c. The gas passes up one side G AS and down the other, and from the top a constant small stream of weak annnoniaeal liquor trickles down. Such a scrubber, it is stated, is subject to clogging by deposits of tar, and equally eflicient work is done without that draw- back by an apparatus in which perforated iron plates occupy the place of the coke, and in the Livesey scrubber layers of thin deal boards are employed. These boards are set in tiers perpendicularly, slightly crossing each other, with about of an inch between each tier. Anderson's washer is a form of scrubber recently introduced, in which the interior is occupied with a series of rotating wli-ah-bone brushes, which dip into troughs of annnoniacal liquor, and in their revolution meet and agitate the gas in its passaL_-e upwards through the tower or column. The scrubber shown in section and plan in ﬁgs. 9 and 10 is a form introduced by Mr James Ilislop. It contains 10 tiers of trays of cast iron, perforated with §-inch holes at a distance of 2 inches from centre to centre. The gas passes upwards through these, meeting in its course a shower of arnmoniacal liquor pumped up and distributed by the rose arrange- ment shown in ﬁg. 9. The bottom part of the scrubber, to the height of the ﬁrst course of plates, is ﬁlled with liquor, which is repumped till it reaches the strength (lc-« sired for the manufacturer of ammonia sulphate. T/cc P-zwzgfiers.-—The ordinary lime puriﬁer, by which sulphuretted hydrogen and carbonic acid are abstracted from the gas, consists of a large rectangular vessel seen in seetio11 in ﬁg. ll. Internally it is occupied with ranges FIG. 1l.—Section of Lime Puriﬁer. of wooden trays or sieves A, made in the form of grids of
 * 1,»-inch wood, with about half an inch between the bars.

These are covered with slightly moistened slaked lime B to the depth of about 6 inches, anrl from three to six tiers of such sieves are ranged in each puriﬁer. The gas enters at the bottom by a tube C, the mouth or inlet being protected from lime falling into it by a cover D, and it forces its Way upward through all the trays till, reaching the lid or cover E, it descends by an internal pocket F to the exit tube G, which leads to the next puriﬁer. The edges of the lid dip into an external water seal or lute II whereby the gas is prevented from escaping. The puriﬁer.»- are generally arranged in sets of four, three being in use, through which the gas passes in succession while the fourth is being renewed; and to control the course of the gas current among the puriﬁers, the following ingenious arrange- ment of centre valves and pipes was devised by Mr Malam (ﬁg. 12). It has a cover fitting within it in such a way as to communicate with the pipe at and either of the four inlet pipes, and also to coin- munieate between one of the outlet pipes and the pipe I1, which carries off the puriﬁed gas. The inlet pipes, b, d, f, admit the gas from the central ease to the bottom of the puriﬁers; and the outlet pipes, c, c, g, return the gas from the puriﬁers back to the case, after it has passed up through the layers of lime, and descended at the back of a partition plate in each purifier to the outlet pipes at the bottom. (6 is the main inlet pipe for conveying the gas fro-m the scrubber or the condenser, and his the main outlet pipe for eonveying the gas to the gasholder. The central cylinder contains water to the depth of 10 inches, and the ten pipes rise up through the bottom to the height of 12 lllI'llt'S, so that the mouth of each is