US340640A - Papee stock - Google Patents

Description

(No Model.)

I J. D. TOMPKINS. PROCESS OF TREATING VEGETABLE SUBSTANGES FOR MAKING PAPER STOGK.

No. 340,640. Patented Apr. 27, 1886.

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N. PETERS. Photo-Ulhngnpher, Washvngkm. ac.

UNITED STATES PATENT OFFICE.

JOHN D. TOMPKINS, OF NASSAU, ASSIGNOR OF ONE-HALF TO JAMES ARKELL, OF OANAJOHARIE, AND CHARLES VETHERTVAX, OF ALBANY, NETV YORK.

PROCESS OF TREATING VEGETABLE SUBSTANCES FOR MAKING PAPER-STOCK.

ESPECIEICATTON forming part of Letters Patent No. 340,640, dated April 27, 1886.

St rial No. 170,446. (No model.)

To all whom it may concern:

Be it known that I, JOHN D. TOMPKINS, a citizen of the United States, residing in the town of Nassau, in the county of Rensselaer and State of New York, have invented certain new and useful improvements in treating wood, straw, grasses, and other substances for manufacture of paperstock therefrom, without any waste of material and without any to handling of the same after its first introduc tion into an apparatus provided, and without the aid of any mechanisms and power other than the ordinary pumps and pipes and power to operate the same; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same,

The objects of my invention are to simultaneously disintegrate in a thorough and uniform manner all the particles of material to be treated, whether of wood, straw, grasses, i

or other material suitable for making paperstock, and also uniformly dissolve all the water-soluble portions of the lignine, so as to expose only the insoluble portions of the same, together with the cellulose portions, to the ac tion of alkaline liquor, and thereby enable this liquor to be used in a more effective manner,

with a less per cent. of alkali material, and to leave at the lower side of the mass of material and neighboring the discharge-opening of the digest-er the dissolved foreign substances, and also to expose all the particles of the material 5 in a uniform manner to the action of the constantly-circulating liquors and waters it is heated with by means of alternating reversed directions of the currents of said liquors and waters through the mass, so that the particles will not become packed on the bottom of the digesting-chamber, and so that all the particles in the mass will be simultaneously acted.

on and have their soluble portions uniformly dissolved and the cellulose portions uniformly .5 disintegrated, and to thoroughly wash and rinse from the material all traces of soluble portions, alkali, and bleaching substance, together with the coloring-matters in the mate rial, by alternate reversal of circulation of the washing-waters; and, finally, by a series of treatments of the mass within the digestingchamber in a progressive successive order, (as will hereinafter-be fully described,) without removal or transfer of the material after be ing first introduced to any other vessel, to so C digest the material, separate the cellulose from a the lignine, and disintegrate the fiber and bleach the same that the resultant product will be more quickly produced than heretofore, and be of a uniformly-line quality and 6;)

free from all chemical substances and colori ugmatter', and be bleached, and colored with any color or shade of color preferred.

7 To carry my invention into effect, I provide an apparatus consisting of a digesting cham- 6 her situated between two oppositely-located anti chambers, which latter are each separated from the former by a finely-perforated Wall or diaphragm, and a system of pumps and pipes provided with suitable "alves, by means of which the different liquids or liquorsviz., the cooking-water, alkaline liquor, bleachingliquor, several washing and rinsing waters, and the coloring-liquors\\'ill be successively circulated (in their respective times of treat 5 inent) through the mass of material to be op erated with in alternating reversed directions until'each kind of liquor and liquid employed has acted on the respective portions of the material as intended to be effected to'the ex tent required by each.

The preferred form of thisapparatus is illus trated in the accompanying drawings, in which A is a shell, made of boiler-plate, preferably with a diameter of about six to eight feet, and a length of about eighteen to twenty-four feet, more or less. This digester-shell is lined with any suitable material which will prevent the acids or other substances within the appara tus from corrodingthe metal of the wall prop- 0 er of the shell. This shell is preferably arranged stationary and vertical, and may be supported from any proper piers or support ing-base. Central within this shell is the digestingchamber A, and at each end of this shell are chambers O O, which I denominate anti-chambers. These outer chambers are each separated from chamber A by walls or diaphragnis B 13, provided with a series of small perforations, I) I), and form, respectively,

the perforated bottom B and perforated top wall, B, of the digesting-chamber; Material is introduced within this digestingchamber A through man-hole D, which is closed by plate d, and a dischargeopening provided with a discharge-pipe, D, having valve d, is made at the opposite end of the said chamber for the discharge of the product from the same.

Neighboring the lower end of shell A are pumps E F, connected, respectively, with coact-ing draft and discharge pipes, which are connected with the chamber of said shell. The draft-pipe e is arranged between anti-chamber C and pump E, and discharge-pipe 6 between said pump and lower or opposite end antichamber, C. These pipes are each provided with a proper valve, as i 1'.

Connected with draft-pipe e are a series of liquid-supply pipes. H, I, J, and K, each provided with a suitable valve, h. One of the series ofpipes,as H, is thehot-water-supply pipe, and pipe I a cold-watcr-supply pipe; J, the alkaline-liqu0rsupply pipe, and K the chlorine-liquor-supply pipe. Each of these pipes connects pipe 0 with its respective vessel or tank, (not shown,) and holding the hot and cold waters and liquors to be employed for treating the material within the digestingchamber. The draft-pipef connects the pump F with the lower anti-chamber, C, and discharge-pipef" connects said pump with the opposite end anti-chamber, C. These pipes f and f are each provided with suitable valves, Z Z.

Connecting with discharge pipef are branch discharge-pipes L, M, and N, of which one is for discharge of hot water, as pipe L, and another, as M, for discharge of alkaline liquors, and the other, as N, for discharge of the chlorine liquor. These pipes are each provided with suitable valves,and lead from pipe f to the respective vessels or tanks (not shown) for receiving the respective liquors.

O is a live-steam pipe connecting with a steam-generator and with pipe 0', provided with branches 0 0", which are connected with the respective anti-chambers C C. The pipe 0 is provided with any suitable handvalve, and preferably with a check valve, and branches 0 O are also each provided with a valve, 01. r

A waste-steam pipe, P, connects the upper anti-chamber, C, with the hot-water tank (not shown) by means of any suitable coil placed within the same, as is generally practiced by trade. This pipe is also provided with asuitable valve. Another pipe, Q, provided with a valve, connects the top of upper antiehamber,C,with a tank (not shown) for leading the chlorine gas or other bleaching-gas to the water or chlorine water for reuse in the subsequent treatment of other charges of material to be bleached.

G is a discharge-pipe,provided with a valve, g, and leading from thelower side of the antichamber C; Through this pipe the waste water or drainage of the treating-liquors can be 7 drawn away. Another pipe may be connected with this pipe G andlead to the hot-water tank, for leading the hot water used last for rinsing to thattank for its reuse for rinsing or for hotwater cooking of a subsequent charge of material, and thereby save fuel. The upper end of discharge-pipe e and discharge end of discharge-pipe are preferably connected with a Y-pipe or ring-form pipe arranged within the respective anti-chambers, and provided with numerous largeperforations, so as to make the discharges of the respective pipes e f diffusiv'e in character. The perforations in the walls or diaphragms B B are to be made larger or smaller than one-eighth of an inch, accordingly as the nature of the material to be treated will require, (as well known by the trade to be,) and in their aggregate area of openings they should equal one and one-half or two areas of the bore of discharge-pipes e f. The pumps E and F are preferably rotary pumps of any known kind, and suitable for operating with their coacting pipes for drawing and discharging liquids.

The above-described apparatus is well adapted to be used for carrying my invention into effect; but its parts can be modified in form and relative arrangements, as the conditions of the surroundings of the apparatus may require for economy and convenience for operations with the same.

In charging this apparatus wood, straw, grasses, or other material for making paperstock is introduced into the digesting-chamber A through man-hole D, and while being in troduced hot water will be forced into the bottom of said chamber through the perforated diaphragm B from chamber C to a height about on a plane with thenpper margin of the latter chamber. This introduction of the hot water will be effected by means of rotary pump E, drawing hot water through pipes H and e,

and discharging through pipe 6 into chamber C. After the chamber Chas been filled pump F will draw through pipe f the water from chamber C and discharge the same into the upper anti-chamber, 0, through pipe f, the pump E at the same time feeding hotwater into the lower chamber. The hot water discharged into upper chamber, 0, will be showered down through the many small perforations in diaphragm B on the material being introduced through opening D above. This operation of filling in the material to be treat ed and showering down the same will be continued until the digesting-chamber A has been filled with the material in a soaked con dition up to the top of the digesting-chamber or to perforated wall B, with the water filling up the same and the upper anti-chamber, C, to a plane with the discharge end of pipe f. Pump E will then be stopped, and pump E will continue its operations of drawing the water from the lower end of chamber C and discharging the same into upper chamber, C, when the water in the digesting chamber will be made to circulate downward through the mass of material in that chamber in a constant manner. Vhile this downward direction of circulation of the water through the mass is going on steam will beintroduccd into the upper chamber and the digestingchamber through live-steam pipes O and O. The volume of steam so introduced is to be maintained so as to heat the water in the digesting-chamber while it is circulating to a degree a little below boiling-point, so that the cooking of the material will be had with the water below boiling and not above boiling heat. This downwardly direction of circulation will be continued by means of pump F for ten (10) to thirty (30) minutes, more or less, accordingly as will be required by the nature of the material treated and its tendency to precipitate and pack down on the perforated bottom B. The circulation of this cooking-water will then be reversed to an upwardly direction by stopping the operation of pump F and operating pump E, when this pump will draw the hot water from upper chamber, C,,and discharge the same through pipe 6 into the lower chamber, 0. This direction of draft and discharge of the cookingwater will cause the same to circulate in an upwardly direction through the mass of ma terial in the digesting-chamber, and this direction of circulation will be continued with the cooking-water maintained a little below boiling for ten (10) to thirty (30) minutes, when the direction of circulation of the water through the mass of material will be reversed and made to be again circulated in a downwardlydireetion by operations of pump F and its coacting pipes ff, as before described, for ten (10) to thirty (30) minutes, when the circulation of this cooking-water will be changed in its direction to that of an upwardly course by means of pump E and its eoacting pipes e c. This alternation of the directions of circulation of the cooking'water or reversal of the currents of the same through the mass of material will be continued for from one (1) to four (4-) hours, according to the nature of the material treated, and the finish of this watercooking will be made with an upwardly direction of circulation through the mass, and from the discharge-opening of pipe D, so that all the dissolved and disengaged portions of the lignine of the material treated will be brought to the lower side of the mass within the digester, and be prevented from passing up through the same, the material operating as a straining medium and permitting the upward passage of the water, so that the thickened substance resulting from this hot-water cooking will be in situation mostly neighboring the discharge opening to discharge-pipe D,for immediate and first discharge from the bottom of the digesting-chamber, instead of being left as a deposit on the top surface of the mass treated, as is had in those processes where the circulation is in one direction only, and that downward, as heretofore.

It should be understood that by cooking with water above boiling temperature the coloringmatter in the material will be more or less fixed in the disintegrated particles, and as a consequence a larger per cent. of bleaching material will be required to clear the fiber of such color taken up by it in overcooking. In this first step of my process I avoid this overcooking, and consequent fixing the color, as is done in the old process, and 1 effect a partial disintegration of the material and a dissolving of all the water-soluble portions of the gums, acids, and other parts of the lignine in the material, and leave only those substances associated with the cellulose which will by the subsequent alkaline cooking be readily dis solved while completing the perfect disintegration of the material begun to be had by this water-cooking, and the advantageous results attending this water-cooking in the manner above described are, that in the subsequent treatment the measure of foreign substances in the material to be affected by the alkalineliquor cooking will be greatly reduced from that which otherwise would be required to be affected were this water-cooking omitted, and a less measure of alkali will be required to dissolve the remaining portions of the lignine and complete the reduction of the material to fiber.

The second step in this invention is the complete removal of all the dissolved foreign substances from the material. This is done by pure hot-water washing and rinsing. After the water-cooking is completed valve 9 will be opened, and the accumulated dissolved foreign substances in the water at the bottom of the digester will be discharged therefrom through pipe G into the \vastemain, and while being discharged the more pure and clear water above the bottom of the digester will run or circulate by gravity downward through the mass in the digesting-chamber and carry with it the loosened foreign substances. After this cooking-water has been drained from the mass pumps E and F will be operated to fill the digesting-chamber with pure hot water, (not boiling,) when pump F will be stopped, and the operation of pump E will be continued with the valve of the hot-watersupply pipe closed for about five minutes, to effect an upward circulation of this water through the mass, when the circulation will be reversed by stopping pump E and operating pump F, and this washing or rinsing water will be made to circulate downwardly through the mass in the digesting-chamber for about five minutes, when the direction of the circulation will be reversed by operatin gpum p E and stopping pump F. This upward circulation of the water will be continued for a few minutes, when the pump will be stopped and the water discharged into the wastemain through waste pipe G. A second washing and rinsing with hot pure water will be made in substantially the same manner, when it will be found that all the water dissolved substances will be washed out from the mass of material in the ICO IIO

digesting-chamber, and the bulk of the material will be considerably reduced from its original measure. The complete removal of these dissolved substances can be readily ascertained by examination of samples taken from tester T. The third step in this invention is treating the resultant product from the hot-water cooking and washing withan alkaline-liquor cooking for the complete removal of all the lignine and other substances remaining associated with the pure cellulose and the complete disintegration of the latter and its reduction to fine fiber or paper-stock. The digesting-chamber is now filled with the alkaline solution orliquor by means of the two pumps and their coacting pipes (the pump E drawing through pipe 6 and alkali-liquor-supply pipe J) in the same manner as when that chamber is filled with cooking or washing water above described.

In the practice of this invention I ascertain by proper chemical analysis of the kind of wood, straw, grass, or other material to be made into paper-stock the nature or charac ter of the alkali natural to and in the material, whether potash or soda, and the per cent. of each therein contained and forming constituent parts of the material to be reduced, and, having ascertained these facts, I provide an alkaline solution which will be in harmony with and have aiiinity for the alkali in greatest measure natural in the material to be treat ed and reduced. This solution or liquor is made with a strength proportionate to the per cent. of silica and othersubstances to be resolved, which will be previously ascertained by the analysis made. in most cases potash is preferable, as this kind of alkali is generally contained in vegetable materials in a much larger quantity than is soda or lime. After the digesting-chamber has been filled the liquor will be brought to a boil under pressure of live steam introduced from any suitable steam-generator through pipe 0 and its branches; and this alkaline cooking of the material will be proceeded with while the liquor is circulated through the mass of material in the digester alternately in upwardly and downwardly directions by means of the pumps E and F and their coacting pipes, being alternately operated in the same manner as when the water cooking and washing were in progress. I prefer to commence this cooking in the alkali liquor with the circulation of the same in a downwardly direction, and continue the same for from ten to thirty minutes by operating pump F, and then reverse the direction of circulation by operating pump E for a similar length of time, when the circulation will be again reversed by operating pump F and stopping pump E, and this reversion of the circulation of the liquor will be made at each ten to thirty minutes, (more or less,) accordingly as the nature of the material will require, and until the cooking is fully completed and the foreign substances are all dissolved, with the pure cellulose or fiber finely disintegrated and reduced suitable for paper-stock. This cooking will be completed when thecirculation of the liquor is in an upwardly direction, so that the dissolved portions of the material will be deposited at the lower side of the mass by the straining of the liquor in its upward passage through the same, which will effect a stoppage of all the thickened portions at the lower side of the mass and neighboring the lower anti-chamber, G, for ready discharge through pipe G. \Vith some materials the perfect disintegration and reduction of the cellulose to fine fiber or paper-stock will be effected by the above dc scribed process of alkaline cooking under reversed circulations of the liquor in from one to two hours, while with other materials the time required will be from two to four hours, (more or less;) and in all cases the progress and completion of this cooking can be readily ascertained by examining samples taken from testerT from time to time. \Vhen this alkaline cooking is completed, the pumps will be stopped, and the valves of their respective coacting pipes will be closed and vent V will be opened, and valve 9 of discharge-pipe G will be also opened, when the thickened portions ofthe liquor,containing the dissolved lignine, will be discharged from said pipe, while the less thickened portions will be carried down from between the particles of disintegrated fiber, and be also discharged, as the body of the liquor circulates downward, by its gravity through the mass to its discharge, or is drawn down by means of pump F and pipe f and discharged into some suitable vessel through pipes f and M, preparatory to being evaporated and reduced by burning to potash, soda, or other alkali for reuse.

The fourth stepthe washing from the reduced material all traces of alk ali-will then be proceeded with. In this operation the digesting-chamber will be filled with hot water, as in the first washing above described, by means of pumps E and F and their coacting pipes, when this water will be circulated alternately upward and downward by operating the said pumps alternately, as before described, for a few minutes each, when this first washing and rinsing water will be drawn off through pipe G. A second charge of hot washing and rinsing water will be made, when the pumps will be again operated alternately for a few minutes each, for causing this water to be circulated in reversed directions at alternate times, as before described. If on examination of simples of the fiber taken from tester T it be found that all the alkali is not removed, a third washing and rinsing will be had in the same manner. When this washing is fully completed, the water will be permitted to drain from the material in the digesting-chamber, and the resulting material will be in condition for treatment with the bleaching solution, which is the fifth step in the progress of this invention. The bleaching-liquor will be introduced into the digesting-chamber from any tank containing the same through pipes K, e, and e and pump E until said chamber is filled, This bleaching-liquor, preferably chlorine liquor, is now circulated through the material within the digesting-chamber in'alternate times of reversed directions by alternating the operations of pumps E and F, so that for a few minutessay from ten to twenty minutes-this liquor will be made to circulate upwardly through the mass of reduced fiber, and then for about the same length of time downwardly through the same, and then again upwardly for a like time, and then downwardly, so on continuing this reversed circulation until all the particles of the fiber have been acted on by the bleaching agent in the liquor to the extent required. By means of the tester T the operator can readily ascertain when this treatment of the fiber is completed by taking samples of the fiber from the same from time to time. This treatment of the fiber to the action of the bleaching-liquor will be finished with an upwardly direction of circulation, as before described, to be had with the hot-water cook and alkaline cook in this process. 'Whcn this bleaching treatment is completed and the pumps stopped and all the valves of their coacting pipes are closed, the valve ofbleaching-gas pipe Q will be opened, and a pressure of live steam will be intro duced into the digesting-chamber from antichamber 0 below, so as to drive the chlorine gas (or other bleaching-gas) in the liquor up ward to enter pipe Q, and be discharged hence into any suitable tank or vessel of water or bleaching -liquor, to be preserved for reuse. After the volatile portions of this bleaching-liquor have been forced out from the digesting -chamber, the liquor will be drawn off through pipes f, f, and L by means of pump F, and discharged into the same vessel the gas was discharged into, or any other suitable vessel for containing the same. This bleached fiber now contained within the digesting-chamber will now be washed and cleared from all traces of chlorine or bleaching substances by introducing hot pure water until that chamber is filled,when the bleached fiber will be washed and rinsed by a succession of reversed circulations of this water through the inass by means of the pumps E and 1* and their respective coacting pipes operating at alternate times, as in the prior washings above described. \Vhen this washing and rinsing have been completed, the water will be drawn off through pipe G, and with a second charge of washing and rinsing water, also hot, the fiber will be again operated with bya succession of reversed circulations of the water through the mass. After the discharge of the water from this second wash a third charge of hot water can be made and circulated as before described if by the two washings of the fiber all the bleaching material is not fully cleared from the same. \Vith the last washing with pure water the resulting product in the digestingchamber will be the finely-disintegrated fiber or paper-stock, ready to be colored, or discharged into any suitable vessel, to be from thence immediately used for making paper, or to be otherwise operated with or cared for for future use. When this resultant product is to be colored before its discharge from the apparatus, the coloring-liquor will beintroduced into the digesting-chamber, containing the paper-stock, until it is filled, and will be circulated alternately in reversed directions, the same as were the cooking-water and alkaline and bleaching liquors, by means of the pumps and their pipes.

The discharge of the resultant paper-stock, whether plain or colored, will be effected through discharge-pipe D.

It is well known that in the process of cooking the materials for reduction to fiber or paper-stock the soluble portions of the same will be taken up by the cooking-liquor, which will gradually become thickened by the dissolved substances separating from the pure cellulose. In the old processes, where the cooking-liquor is circulated continuously down ward, the material becomes compacted in the lower portion of the digester, and the top portion of the mass operates as a strainer to prevent the thickening matter in the liquor from passing through the same, so that all the gum my portions of the dissolved substances associated with the fiber will be deposited in the uppermost portions of the compacted mass, and necessitates the transfer of the material to aspecial washing-machine for effecting a cleansing of the fiber from the gums, acids, and other dissolved substances mixed in with the same, which washing is attended with a considerable amount of labor for handling the ma terial, and the use of much fuel if the water is used hot, and the employment of a very great amount of water and considerable power for agitating the samewhile the washing is proceeded with.

In the old processes, where the cooking-liquors are circulated in one direction and downwardly continuously, the liquor is gradually weakened in its strength as it passes downward through the compacted mass and strained by the upper portions of the same, as a large portion of the alkali in the liquor is taken up by the dissolved portions of the lignine and held from acting on the undissolved portions below, so that additional alkali is re quired to be introduced from time to time to maintain a proper strength of liquor. In these old processes the continuously downward direction of circulation of the cookingliquor through the mass of fiber operates to produce in the same a few vertical channels, through which the liquor will freely pass and more rapidly affect the particles of the material immediately around these channels, while those particles more remote are less affected, as are also those portions of the material nearer the bottom of the digester; hence to complete the cooking of all portions of the material in these old processes some of the parts will be overcooked, while if overcooking be ICO prevented some portions will not be properly cooked, and must be strained off by a subse quent operation to be recooked or otherwise operated with or be thrown away. In either case a loss will be had of either the good material or of time and power for the proper reduction of the same.

'One of the distinguishing features of this invention is the cooking of the material in hot (about boiling) water while the latter is circulated through the former at alternate times in opposite or reversed directions, preferably downward and upward,so that all packing of the material will be prevented, and the cooking-water will be made to move in such an active contact with all the particles of the material treated that they will be made to move against each other in a loosened manner in all portions of the digester,and cause all the particles to be simultaneously and uniformly cooked, and the soluble portions of the lignine (dissolvable in water) to be uniformly dissolved,and the coloring-matterextract-ed from the material, and thereby prod uce a partial disintegration of the material and a considerable reduction of its bulk and removal of the larger portion of the coloring-matter originally in the material, so as to leave (after washing) a less quantity of lignine to be dissolved and less work of disintegration of the material to be effected by the subsequent alkaline cooking, and a less amount of bleaching to be had in the final'blcaching process to which the fiber will be subjected.

Another distinguishing feature is the cooking ofthe material with boiling alkalineliquor under pressure while the latter is circulated through the body of the former continuously and in alternating reversed directions, preferably downward and upward at alternate times, wherebyapacking of the particles of the treated material in the lower portion of the digesting-chamber, as heretofore had, is effectually prevented, and the liquor is made to uniformly saturate and envelop all the particles being treated, and operate with equal strength on the same, while the particles are being stirred against each other and constantly changing in their relative situations in the digesting-chamber, so that the alkali of the liquor will be brought into the most effective contact with all the particles and act simultaneously and uniformly on all the soluble matters associated with the pure cellulose in the treated material, and thereby rapidly effect a complete disintegration of the material and reduction of the same to fine fiber without any portions of the same being overcooked While other portions are only sufficiently cooked or undercooked, as heretofore had in the old processes.

Another distinguishing'feature of this invention is the treating of the disintegrated pure fiber to the action of a bleaching-liquor, (preferably chlorine liquor,) with or without pressure, while it (the liquor) is being c011- tinuousl y circulated through the mass of fiber in alternating reversed direetions,whereby all the particles of the fiber will be in a state of constant movement in the liquor, and be simultaneously and uniformly acted on by the chlorine or other bleaching agent held in the 'water, which saturates and penetrates these constantly-moving fibers, so that each fiber will be as effectually acted on both externally and internally by the bleaching agent as the others. The advantageous result had from this part of my invention is that the bleaching of the fiber can be effected without any handling whatever in a few hours, where in the old processes it required treatment of two or more days and employment of labor to handle and stir the mass being treated, so as to expose all portions to the action of the bleaching agent, which is wholly done in the practice of my invention by the reversed circulations of the bleaching-liquor.

Another distinguishing feature is effecting the advantageous deposit of all the dissolved portions of the lignine associated with the cellulose and resulting from the water-cooking or alkaline-cooking at the lower side of the mass and neighboring the waste discharge pipe by finishing the cooking with an upwardly circulation, so as to cause the unaffected portions of the material treated to operate as a strainer by permitting the passage of the purer cooking water or liquor upward, and holding the thickened dissolved matters from having such passage and stopping the same at the under side of the mass for ready discharge from the digesting-chamber without retention within the mass; and by this operation I obviate the necessity of removal of the cooked material to a special washing-machine and the necessity of employing power for continuous agitation of the material in water.

The advantageous results had by the practice of this invention are that with a single attendant and a single apparatus provided with mechanism by which the water and liquor (employed in the several successive treatments above described) will be constantly and repeatedly circulated through the mass of the material within the digesting-chamber in alternating reversed directions, I am enabled in a period of from six to twelve hours (more or less. according to the nature of the material treated) to dissolve and remove all the lignine associated with the pure cellulose, and reduce the latter to pure fine fiber or paper-stock in a suitably-bleached condition without the removal of the material from the apparatus or any rehandling of the same, as is required in the old processes, while at the same time the fiber will be so evenly cooked and reduced that it will be softer and stronger than the stock treated by the old process, and the reduction will be effected without any waste of either material or fuel, and the use of many different machines and apparatuses heretofore employed and the consequent numerousrehandling of the material and expense attending the same in the practice of the old processes will be fully obviated.

IIO

It should be understood that if acids forcooking or treatment of the material is preferred in lieu of alkali, liquors of those substitutes can be circulated in alternate reversed directions through the mass treated with the same advantageous results, and in such cases the digester should be lined with some material which will not be affected by those substitutes.

I have described my new process when a single digesting-chamber is used; but, if preferred, this process can be practiced in an apparatus employing two digesters properly connected with each other by suitable pipes, so that when the circulations of the treating waters and liquors are upwardly through the mass in one digesting-chamber they will be downwardly through that in the other, and the reverse alternately, when the same advantageous results will be had as when the successive treatments are had in a single digester.

I am aware that it is not new to circulate the treating'liquids through the body of wood, straw, or other particles of vegetable materials, as such process was practiced by Dixon and Harding in their apparatus, described in Letters Patent No. 5=t,510, granted May 8, 1866. In this old process the material at the bottom portion of the digester would be com pleted and withdrawn before the other portions above were finished, and at each withdrawal of the finished pulp a fresh small charge of raw material would be introduced from a chamber above, when fresh liquor would be introduced from an exterior tank into the lower end of the digester for contact with the more nearly-finished portion which had previously replaced the withdrawn finished pulp; and the treating-liquor in this old process was made to have, save in the interruptions, a constantly downward circulation through the differently-treated portions of the material in the digesting-chamber by the force ofa pump situated in the eourseot' a single pipe which drew from the lower end of the digester and discharged into the upper end of the same. This old mode of procedure forms no part of my invention, as in my process the digestingehamber isat first sufficiently filled bya single charge with the material to be treated until completion in all its portions, and is then treated continuously and uniformly, so that the particles will he held substantially in suspension in the liquor, while thelatteris forced by the actions of suitable reversely-operating pumps to circulate in one direction for a suitable length of time by one of the pumps being operated for the time, and then in an opposite direction by the other pump forasimilar length of time, to be followed by repeated and similar alternating reversed circulations of the liquor by the alternate actions of these pumps until all the particles of the material are uniformly and completely finished for withdrawal, or for discharge of the liquid or liquor from the completed pulp.

I am also aware that it is old to treat single and full charges of material until completed, as instanced in Letters Patent No. 117,427, granted to S. A. Keen, July 25, 1871; but this treatment was had in digesters which were mounted on hollow trunnions and revolved, and which were provided with steampipes and suitable valves for communicating from the hollow trunnions to the opposite ends of the digester, so that from time to time the currents of steam were at will momentarily reversed i'or clearing the strainer at one end of the digester. Such operations form no part of this invention, as in all the time of treatment of the material by this old process the changes of the liquor in relation to the particles of material were only effected from the rotation of the digester, which agitated both the liquor and the material as the same were shifted alternately from one end to the other in therotation of the di gester, while thesteamcurrents were only momentarily changed for clearing the strainer of adhering particles. In my process this shifting of the mixed material and liquor from one end to the other of the digester, as in this old process in rotary digesters, is prevented, and the material is made to be constantly suspended in the treating-liquor in the best condition for the active circulation of the treatingliquor between the suspended particles in alternatelyreversed directions under the force of the reversely-opcrating pumps employed at alternate times, whereby the liquor is made to affect every particle of the material uniformly the same as all the others until the completion of the treatment.

I am also aware of the process of treating single and full charges of material with digesting-liquors, as in the Lahousse patent, No.

148,125, dated March 3, 187st, in which was employed a rotary digester (similarly mounted on trunnions, as in Keens patent) provided with a system of internally'arranged steampipes and a central steam-pipe having perforated radial tubular arms, by which currents of steam entering the central pipe and escaping from the radial arms operated to effect a circulation of the steam through the body of the mixed material and treating-liqnor, by which the latter will be kept boiling while the digester is rotated, while in my process I produce an active circulation of the treating-liquor through the entire mass of material in alternating reversed directions without employment of steam as a force to give motion to the liquor, or a rotary movement of the digester for shifting the material, and am also enabled to circulate the liquor, as described, by the force of the alternately-opcrated pumps without boiling the same when it is preferred to use the treating-liquor below boiling heat.

I am also aware of the process of digesting materials for making pulp by employment of cooking-liquids with the same in rotary digesters similar to that shown in Patent No.

ICO

IIO

206,277, granted to Thorpe, July 23, 1878, in v which steam is admitted at intervals as the digester is revolved through a cut-off connecting by means of hollow trunnions with two interior perforated distributing-pipes, to which the steam is admitted alternately as the digester is revolved. No part of such old process forms a part of my invention, for I dispense with the use of steam for effecting a circulation of the treating-liquor employed.

Having described my invention, what I claim, and desire to secure by Letters Patent, 1s

1. In the manufacture of paper stock orfiber, the process above described of dissolving the gums, acids, and other watersoluble matters associated with the cellulose,of wood, straw, and other vegetable materials, which consists in confining the material within a chamber which is between two adjoining and oppositelylocated chambers and separated from each by a perforated diaphragm, then subjecting this confined mass of material to the action of highly-heated water, which is repeatedly circulated through all of said chambers and the confined mass in alternating reversed directions by means of reversely-operating pumps which are operated at alternate times, substantially as described.

2. In the manufacture of paper stock or fiber, the process above described of disintegrating wood, straw, and other vegetable subtances, and dissolving the gums, acids, and other matters not soluble with water and associated with the cellulose in said material,which consists in confining a mass of said material within a chamber situated between two adjoining and op positely-loeated liquid-chambers, which are separated from the former by perforated diaphragms, then subjecting this confined mass of material to the action of a chemical liquid which is capable of dissolving the said gums and other matters when heated under pressure of steam, and repeatedly circulating the same through all the said chambers and through the confined mass in alternating reversed directions by means of reversely-operating pumps which are operated at alternate times, substantially as described.

3. In the manufacture of paper stock or fiber from wood, straw, and other vegetable materials, the process above described of gathering and depositing below the mass of previously disintegrated cellulose the dissolved gums, acids, and other matters associated with said cellulose, which consists in drawing forasuitable length of time by means ofapumptheeooking-liqnorfromtheupperend of the chamber containing the mass, and again introducing the same liquor by means of the same pump into said chamber at its lower end and below the mass to circulate upwardly, while the disintegrated cellulose operates as a strainer, substantially as described.

4. In the manufacture of paper stock or fiber, the process above described of bleaching in bulk the cleaned disintegrated cellu lose or fiber, which consists in confining the mass of fiber within a chamber situated between two adjoining and oppositely-located liquid-chambers, and separated from each by a perforated diaphragm, then subjecting this confined mass of cleaned fiber to the action of a bleaching-liquor, which is repeatedly circulated through all said chambers and through the said confined mass of fiber in alternating reversed directions by means of reversely-opcrating pumps which are operated at alternate times, substantially as described.

5. In the manufacture of paper stock or pulp or fiber, the process above described of washing, rinsing, and clearing the disintegrated fiber from the dissolved matters and chemicals adhering to and associated with the fiber after the withdrawal of the previouslytreating liquids or liquors, which consists in subjecting the mass of fiber, when confined within a chamber situated between two neighboring and oppositely-located chambers and separatedtherefrombyperforateddiaphragms,

to the action of repeated circulations of pure 2 water by the force of reversely-operating pumps which are operated at alternate times through all said chambers and the confined mass in alternating reversed directions, with suitable durations of circulation in each direction, substantially as described.

6. In the manufacture of paper stock or fiber, the process above described of treating wood, straw, and other vegetable materials for reduction to pulp or fiber, which consists in confining the material within a digesting-chamber which is separated by perforated diaphragms from liquid-chambers which adjoin the respective opposite ends of the digesting-chamber, then filling all the chambers with cooking liquid or liquor and heating the same under pressure of steam, then holding the material in suspension in the cookingliquid by the alternate operations of reversely-operating pumps and coacting pipes pro vided with suitable cocks and having connection with both said liquid-chambers, and repeatedly circulating the cooking-liquid in alternating reversed directions by means of the same pumps operated at alternate times through this suspended mass of material,with suitable durations of circulation in each direction for preserving such suspension, sub stantially as described.

7. In the manufacture of paper fiber or stock from wood, straw, grasses, or other known equivalent material,the continued progressive process above described, which consists in circulating the differing and respective cooking-liquids above described through the material in the digester in alternating reversed directions with that of the hot-water cooking, followed by the hot-water washing and rinsing and preceding the alkalinecooking, substantially as described.

8. In the manufacture of paper stock or fiber from wood, straw, grasses, or other equivalent material, the continuous and progressive process above described, which consists in circulating in the order substantially as above described the respective treatingliquids set forth through the mass of material contained Within the digester in alternating reversed directions, With thealkaline cooking following the hot-water Washing and rinsing, preceded by the water-cooking, and followed by the alternating reversed circulations of the bleaching-liquor through the same mass after 10 the alkali has been washed and rinsed therefrom, the material being retained within the digester all the while it is being treated with the respective treating liquids and liquors, all substantially as and for the purposes set forth.

JOHN D. TOMPKINS.

Vitnesses:

ALEX. SELKIRK, CHARLES WETHERWAX.

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