Scientific American Supplement No. 822, October 3, 1891 eBook

This eBook from the Gutenberg Project consists of approximately 128 pages of information about Scientific American Supplement No. 822, October 3, 1891.
the pulp from the last chest, delivers it into a pipe, h, by which it may be conveyed to any desired point, the said pulp having been sufficiently bleached before arriving at the said pipe, h.  It will be seen that by these means all the pulp is thoroughly and uniformly subjected to the bleaching agent and that the bleaching is gradually performed in all parts of the pulp, which is first acted upon by the weaker bleaching agent that has previously operated upon the pulp before treated, and that finally, when nearly bleached, the pulp is acted upon by the bleaching material of full strength, this action being far more efficient than when the materials are simply mixed together, the unbleached material with the strong bleaching agent, and allowed to remain together until the bleaching operation is finished, in which plan the bleaching agent loses its strength as the bleaching operation approaches completion, so that when the pulp is nearly bleached it is operated upon by a very weak bleaching agent.  By having the pulp transferred from one chest to the next in the reverse order to that in which the liquid is transferred it will be seen that all parts of the pulp are acted upon uniformly and equally and that the operation may go on continuously for an indefinite period of time without necessitating stopping to empty the vats, as is the case when the liquor only is transferred from one vat to the next.  A pump may be used for lifting the bleaching liquid, as shown, for example, at k, Fig. 1. where said pump is used to raise the liquid delivered from the chest, a2, and discharge it into the trough, m, by which the pulp is carried to the inlet pipe, b.  By the use of the pump, h, a stronger flow of the liquid into the pipe b, of the first chest, a, is effected than if it were taken directly from the washer of the chest, a2, which is desirable, as the pulp is delivered in the trough, m, with but little moisture.

It is obvious that the construction of the apparatus may be varied considerably without materially changing the essential features of operation.  For example, the washers might be dispensed with and the liquid permitted to flow through suitable strainers from one chest to the next in order, by gravity, the successive chests in the order of the passage of the pulp being placed each at a higher level than the preceding one, and it is also obvious that the construction of the pulp conveyors might be widely varied, it being essential only that means should be provided for removing the pulp from one chest and delivering it into the next while carrying only a small amount of the liquid from one chest to the next with the pulp.

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Scientific American Supplement No. 822, October 3, 1891 from Project Gutenberg. Public domain.
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