USRE7485E - Boyers - Google Patents

Description

.11. L. :EEN s. n. BuRGE'ss,

Assiguors fo AMERICAN WOOD PAPERYO). PROCESS AND APPARATUS FOR EVAPORA'TIIG AND CALCIFING ALKALINE SOLUTIONS.

Ressuad Jan. 30, 1877.

7,485. PROCESSES AND APPARATUS FOR EVAPORATING AND CALCINING ALKALINE. SOLUTIONS. M. L. Keen, Stroudsburg, and Hugh Burgess, Royers Ford, Pa., assignors to American Wood Paper Company. Patent No. 46,244, dated Feb. '7, 1865. [Filed Jan. 1'7, 1877.]

To all whom it may concern Be it known that we, MORRIS L. KEEN, 0f Stroudsburg, in Monroe county. and State of Pennsylvania, formerly of Royers Ford. in

`lVIOntgOmery county, and State of Pennsylva nia, and HUGH BURGEss, of said Royers Ford, have invented certain new and useful improvements in recovering alkali for use in pulping wood, and similar vegetable substances,from the alkaline solutions with which such substances have heen treated` and in apparatus for evaporatiug and calcining such alkaline solutions, and Vthe following is a description of the process and the construction and operation of the apparatus for performing the same, which We have invented, reference heing had to the accompanying drawing, making part of this specilcation, in Which- Figure l represents a longitudinal and vertical section, taken through the body of the main furnace. Fig. 2 represents a vertical transverse section through the line x x of Fig. l, and showing also in section the calciningfurnace connected thereto. Fig. 3 represents a front elevation of the evaporating-t'urnace, and a side view of the calciningfuruace.

Similar letters of reference, Where they occur inthe separate figures, denote like parts in all the drawings.

In the process of pulping or disintegrating wood, straw, and other similar fiber-yielding substances by the use of alkaline solutionswhich, as is well known, are prepared by dissolving soda-ash of commerce or commercial caustic soda or alkali in water with lime, then settling thesalne and drawingoff the clear alkaline solution with which the wood is treatedit is desirable to recover the alkali in such so- .ing the liquors in which the vegetable mat ters have been treated, to a' state-ofV dryness,

-and completing thercstora-tion of the dry mass to ashy similar to the original whence the fresh 1 alkaline solution, wasv obtained for the pulping process, by burning and calcining the same. I Y

For this purpose we make use of a furnace constructed and operated in such manner that the liquid to be evaporated on thesole or hearth of the furnace is directly exposed to theV llame and hot gasesfrom .the lire, which are.

urged by a blast or strong draft. And when the solution is evaporated to dryness the mass on the sole or hearth of the furnace is further exposed directly to the llame and hot gases from the Ere in continuation of the process of. 'recovering the alkali, thereby consuming the vegetable matters contained in the mass and completing the restoration ofthe alkali; and

we also use, in combination with the main evaporating-furnace, one or two calcining or finishing furnaces, as an appendage to the evaporating-fnrnace, or separately from it, but forming a continuation of the process of recovering the alkali; and we, moreover, utilize the remainderof the heat of the flame and hot gases from the fire unabsorbed after their passage over the surface of the liquid to be evaporated on the sole or hearth of the furnace, by passing it, before its nal escape to the chimney or stack, o ver and under a series of pans, or their equivalent, through which flows the alkaline solution in its transit from the reservoir to the hearth.

To enable others skilled in the art to make and use our invention, we will proceed to describe the same with reference to the drawing.

A represents the main evaporating-hearth, and B the pan-chamber closed at each end by iron doors C. a represents a reservoir, in which the liquor'to be evaporated is collected Y after the pulping process is performed, and

this reservoir a may be placed, as shown, over the pan-chamber, or in other convenient position. The solution to be evaporated is supplied from this reservoir by a cock or other eontrolable means to the pans b in quantity proportionate to the evaporation to be effected. The alkaline solution lowsl from one pan to the next below it by means of .the overflows b2 until it reaches the hearth A, where it is exposed to the action of the flame and gases from the fire, which is at f. The fire is urged by a blast or strong draft, which enters the ash-pit at f2. The course of the hot air and gases is indicated by the arrows, which show their passage over the surface of the solution Y on the hearth and under and over the pans,

.urged by a regulated blast or draft.

ilamefand hot gases from the. tire urged by a regulated blast or draft, and at a lower temperature than that employed for evaporation, to prevent loss of the alkali bysublimation,

yand the calcination is aided by the combustion of the vegetablermatter contained in the .alkaline mass.

This calcination may be effected in another furnace, in whicha lower degree of h eat is maintained to prevent loss of the alkali by sublimation. In such case the calcining-fnrnace may be separate from the main evaporator, or, as we prefer, attached to it, as shown i in Figs. 2 and 3, at E, and connected with it at or near the bridge wall M. The'calciningfurnace E, or, as we prefer, two furnaces, E E, are constructed in every way similar to the hearth of the main evaporator A, and are provided with tires at their ends f3, which are At the proper stage of inspissation of the solution on the hearth of the main evaporator the said solution is allowed to flow, or may be moved, into the calcining furnace or furnaces E E, and there evaporated to dryness and calcined. The products of combustion of the vegetable matter in the alkaline mass passing over the hearth of the main evaporator are thus utilized. When two furnaces, E E, are constructed they are used alternately, thus obviating the necessity of lowering the temperature of the main evaporator, which is worked continuously.

It is 'obvious' that the number, form, and mode of setting the pans may be altered to suit thev circumstances of the case; or, if itis deemed desirable, in the place ofa series ofVv pans the following may be adopted: A tower constructed of stone, brick, or iron may he filled with pieces of stone, brick, or othersuitable material, down and over which the alkaline solution is made to flow by any suitable arrangement on top of the towel', while the waste or excess of heat from the hearth of the furnace enters the tower at or near its base, and in its ascent is absorbed by the descending alkaline solution, which flows onto the hearth from the receiving-tank.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is-

l. The improved process of rt-coverip'g the alkali from alkaline solutions used in pnlping wood, by first evaporating such solution to dryness, and then consuming the vegetable matter and calcining the alkaline mass by exposing the solution and dry mass directly to the action-of the flame-and hot gases from the re,.substantiall y as described.

2. The improved process of evaporating and calcining alkaline solutions used in pulping wood by exposing the solution until evaporated to dryness, and the dry mass until calcined to the vdirect action of the flame and hot gases from the re, urged by a blast, whereby the vegetable matter is consumed, and the alkali recovered from the solution, substantially as described.

3.v The improved process of calcining alkaline solutions, used in pnlping wood,andvevap orated to dryness, by exposing thevmass to the direct action of thelame and hot gases from the fire, urged by a regulatedblast, whereby the vegetable matter is consumed and the alkali recovered, substantially as described.

4. `In combination with the main evaporat- 'the solution is evaporated vnearly or quite to dryness, in'combination with a pan or pans, or the equivalent thereof, where the heat from l.the fire unabsorbed in its passage over the hearth isutilized for evaporatingthe solution -con'tainedin said pan or pans, substantially as described.

MORRIS L. KEEN. HUGH BURGESS.

Witnesses SAMUEL LEA, TBEoDoRE NYE.

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