US1788840A - Apparatus for washing pulp - Google Patents

Description

Jan. 13, 1931.l o. MANTlus APPARATUS FOR WASHING PLP Filed April e, 192s s sheets-sheet 1 INLIENTOR. Off@ 'M0/7290.5'

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Jan. 13, i O., MANTIUS I APPARATUS FOR WASHING PULP Y Filed April ,6, 1928 3 Sheets-Shet 2 WM AT RNEYS. f

- Jan. 13, 1931.

Q. MANTlUs f APPARATUS FOR WASHING PULP Filed April 6. 1928 Y 5 Sheets-Sheet 5 Patented Jan. 13, l931 PATENT oFl-lca OTTO MANTIUS, OF NEW YORK, N. Y.

APPARATUS FOR WASHING PULP Application led April 6,

This invention is. an apparatus for removing chemicals from pulp produced by the soda, sulphate or sulphite processes well known to the art.

5 In the commercial preparation of pulp, it

is discharged from the digestcr with a con- -siderable chemical content' which it is desired to remove in order to prepare the pulp for bleaching and to recover the chemical l for.- further use. This removal of the chemical has heretofore been accomplished by placing the pulp in large wash tanks or -difusers and washing out the chemical by causing water to flow through the pulp. l Large quantities of water are required in the removal of chemical in this manner and the process islrelatively sl-ow. -Furthermore, the cost is high due to the quantity of the fresh hot water employed and the relatively large amount of water which must be evaporated in recovering the chemical therefrom.

The purpose of the present invention is to free the pulp of chemical through the cmployment of a 'relatively 'small expenditurev of water by the use of simple and eflicient mechanical means, whereby the cost of heating the water employed is 'mi nimized, and the recovery of the chemicals for further use through steam concentration is accomplished with economy and facility.

Generally speaking, the apparatus of this invention embodies means for passing the pulp through a succession of pressure zones, and between each two consecutive Zones,

means is provided for thoroughly washing the pulp as it travels along a predetermined path, so that the pulp moves continuously and the operations are in effect continuous operations calculated to produce maximum output of the machine.

-In its preferred, practical form, the apparatus of the present invention embodies a plurality of consecutively cooperating conve'yors with which are associatedl pressure i. 45. rolls cooperating with the respectivecon al marked departure 1928. Serial No. 267,978.

veyors to form between them converging mouths through which the pulp to be operated upon is passed by the conveyors in vorder that the pulp may be subjected to successive compressing operations. `Positioned con- 5 tiguous to the outlet of each pressure mouth is a shredding and washing device, so that the material after bein compressed is passed through such device and thoroughly shredded and washed.l

The washing operations are carried on with water supplied from any 'suitable source and the purpose of which is to dilute the chemical contained in the pulp so that when the pulp is subsequently compressed in the next succeeding pressure mouth, the water squeezed out of the pulp by this operation will carry with it a part of the chemical conv tained in the pulp.v

By utilizing a machine having a succes` p sion of these pressure mouthsgwith interspersed'shredding and washing devices, the material is passed through the machine in a continuous manner being alternately shredded and washed and compressed in order to alternately dilute the chemical contained in the pulp and thereupon squeeze the dilute chemical solutiontherefrom. The washwaters used in the successive operations are preferably, though not essentially, employed in preceding washing operations in order to economize in water consumption and to produce, as a product, afairly strong solution of thechemical which can be readily concentrated for the purpose 'of recovering the chemical for further use.

The apparat-us of thisinvention constitutes from prior practice. It embodies numerous novely features, some of'-l whichjmay be used without employing all. Among these novel features may be men- `tionedefiicient apparatus for removing the water-chemical solution from the upper wall of each tapering mouth. This apparatus consists, generally speaking, in a soft surface lremoved from squeezed from the suction roll adapted to absorb the water to be it to a position where it is adapted to be roll and delivered to a suitable duct which conducts it away.

Another important feature of the invention is inherent in a novel form of shredding'l and washing apparatus which is so constructed as to shred, knead and simultaneo-usly wash the pulp in order to bring about a most intimate contact between the washwater and the libres ofthe pulpito the end that the dilution ofthe chemical may cal content as expeditiously as possible. c

' Features of the invention, other than those specified, will be app-arent'from the hereinafter detailed description and claims, when read in conjunction with the accompanying rawings.

The accompanying drawings illustrate one practical embodiment of the invention, but the construction therein shown is to'be understood as illustrative, only, and not as defining thel limits of. the invention.

Figure 1 is a diagrammatic view of a machine embodying the present invention.

. designated 2, 3, 4, 5 and Figure `2 is an enlarged detail elevation showing apparatus forming a partof the structure illustrated in Figure l, and functioning to press the pulp in order to squeeze the water therefrom.

Figure 3 is a vertical longitudinal section through shredder and washing apparatus shown diagrammatically in Figure 1. This section is taken on the line 3-3 of Figure 4.

Figure 4 is a plan view of the structure shown in Figure 3.

Figure 5 is a side elevation of the same structure showing the manner in which the moving parts are driven.

Figure is a section showing apparatus for removing a portion of the water squeezed out from the material.

Figure 7 is a section on the line 7-7 of Figure 6 showing certain parts in elevation.

The whole apparatus is preferably, though not sentially, mounted within a suitable casin designated in Figure 1 of thedrawings y the reference character 1. This casing may be of any suitable form o-r construction and may, in practice, be the-room of a building.

By reference to Figurel 1, it will be noted that there are a number of conveyors mounted within this casing, and in this figure, I have shown Afive of them. They are respectively 6. These conveyors are mounted one above the other and in such relation that' they are adapted to cooperate' with one another. Thus, the lower reach 7 of the conveyor 2 ispositioned to cooperate with the upper reach 8 of the conveyor 3. The lower reach 9 of the conveyor 3 cooperates with the upper reach 10 of the conveyor the conveyor and to transportk be as great asV of its chemi-` .so that each projects a distance beyond the other in order that pulp placed on the conveyor 3 to the left of the conveyor 2 in Figure 1 may be fed by the conveyor .3 between the reaches `7 and. 8 to 'bejfed after passing between said conveyors to'ashredder'or washer 15 positioned beyond the discharge end of the conveyor 3.

' This shredder and washer above the projecting portion of 4, so that after the material is passed through the shredder and washer 15, it is fed to the conveyor 4 to be carried thereby between reaches 9 and 10 of the conveyors 3 and 4 and discharged into a second shredder or washer 16 from which it is in turn discharged on to the conveyor 5 to be carried thereby between the reaches 11 and 12 of the conveyors 4 and 5 and thereupon discharged into a third shredder and washer 17, from which it is thereafter discharged onto the lowermost conveyor 6 to be carried thereby between the reaches 13 and 14 and delivered down an incline table 18 through a hole 18 into a trough by which the material is conveyed away.

All of the conveyors 2-6 are of the same construction and I find it practical to employ slat conveyors, such as shown in Figure 2. Here each `conveyor is illustrated as embodying metal slats 20 extending transversely of the direction of travel of the conveyor and for the full width of the machine. These slats are positioned edge to edge and are mounted on s rocket chains 21 by which they are supporte and moved. The sprocket chains operate about suitable spacing and driving sprockets 22 as shown and these sprockets are all driven at the same speed so that the conveyors will all travel at uniform speeds.

The cooperating reaches of the several conveyors have associated with them pressure rolls. That is to say, above the lower reach 7 ofthe uppermost conveyor 2 are positioned a lurality of pressure rolls 23, 24 and 25 an cooperating with the u per reach 8 of the conveyor 3 and positione directly below the rolls 23, 24 and 25 are cooperating rolls 23a 24a and 25a. These rolls are positioned to engage with the backs of the slats 20 of the conveyors with which they cooperate and, as shown in Figure 2, said rolls are positioned at progressively decreasing distances apart. Thus, the rolls 23 and 23a are positioned slightly further apart than the rolls 24 and positioned slightlyfurther apart than the ls positioned the conveyor 24a which in turn are l23, 24 and 25 and the cooperating rolls 23a,

24a and 25a Iare mounted in sultable be'arings, so as to be held firmly in position although the bearings may be' spring pressed ythe conveyors meet converging pressure 30 or weighted as shown in Figure 2 so that if with abnormal resistance due, e. g., to unyielding foreign matter carried into the converging mouth by the material acted upon, the rolls may slightly retract or be moved apart sufficiently to permit the material to pass through without damaging the apparatus. Y

Under normal conditions, however, the

4pressure rolls are mounted so that the cooperating preaches of the .conveyors will not move apart, but will subject the material fed between said conveyors to a constantly increasing -pressure as it is carried along by and withthe conveyors. rial is fed onto the upper reach of the conveyor 3 down a feed table 26 and iscarried by Ithe conveyor into cooperation with the conveyor .2, it will necessaril 'follow that such material will be carrie mouth formed in the manner described whereby the material will be compressed to a substantially solid cake and during thisl operation, a. large percentage of the water contained in the material will besqueezed out therefrom.

The rollers which. I have described are those cooperating with the lower reach of of the several conveyors are 35a, as well l:as the rolls the conveyor 2 and the upper reach of the conveyor 3, but the three setsof rollsassociated withl the other cooperating reaches formed and mounted in the same manner and function for the same purpose as already explained. I refer in this connection to rolls 33, 34 and 35 and their cooperating rolls 33a, 34a .and

their cooperating rolls 43a, 44a and 45a and also the [rolls 53,154 and` and their cooperating rolls 53a, 54a'and 55a. As a matl ter of fact, the several sets of rolls are pres-l sure rolls and .their purpose is to provide suicient pressure to s ueeze out. a' large proportion of the materlal presented thereto and to form the material into a substantiallyl solid cake.- v

.During thepressing operations, considerable water is freed from the material and this water is caught -.b troughs'30, 40 and 50 and which are posltioned directly beneath the upper reaches ofeaehvofthe conveyors '3, 4,

5 and6.

v The Shreddersl andy-washers of which three are shown in Fi rei v'are illustrated' more in 5 inclusive. All of the Thus, if matethrough the 43, 44 and 45 and tank is in the form of arcuate shaped troughs 62a', 63aand 64a. These troughs are curved on radii of which the axes of the respective drums are the centers. `The periphery of each drum has formed thereon pyramidal shaped studs 65 and similarly shaped studs are formed on the inner faces of the troughs in such Ina-nner that the studs of the respective parts are substantially complementary to one another, but are so placed as to permit rotation of the drums in the troughs and with respect to one another. l

The arrangement may be fully appreciated from the showing in Figs. 3 and 4 and it may be stated that there is one less annularrow of studs on the trough 62a than on the cooperating drum 62.. The same relation eX- V I ists as to the drum 64 and thetrough 64a, whereas there is one less row of studs on the drum 63 than on the cooperating trough 63a. This produces a staggered relation of the parts which permits of rotation. Because of the interfitting of the studs, however, the material passed through the washer is subjected to a shreddinor and at the same time a kneading action, wlhile the rotation of the drums-serves to simultaneously feed the material fed into the tank from the feed table v66 longitudinally through the` tank and thoroughly shred and comminute it'.

The material is freed from the last drum I by a comb 67 having a serrated edge complementary to the studs of said drum and this comb interfits with the studs and combs the fibres free from the drum whereby they are caused to fall on to a discharge plate 68 which delivers them to the next conveyor.

The shredding and kneading drums may be operated by any suitable drive mechanism, but .for the purpose of illustration, Iha've shown-the drums as having drive pulleys 626, 636 and 64b with which a belt 69 is associated. This belt is passed over the lseveral pulleys referred to and around directional and tensioning ulleys 70 and embraces .a

pulley. 71 mounted on the shaft which drives the conveyor 3 so that the several drums are driven from the shaft 7 2 which drives the conveyor 3, whereby the several drums are driven with the said conveyor. e

By reference to Fig. 1, will be noted that the shredder and washer 17 isI supplied with fresh water through a pipe 73. The shred- 'de'r andvwasher 16 -is supplied from water in the trough-60 through a pipe 74, while 'the shredder and washer 15 is supplied by water 76 delivers water les from the tank 50 through a pipe v75. A pipe .40 to t e from thetrough outlet pipe 84 which leads to suitable recovery apparatus. Suitable' pumping and 10 parts of pulp,

terial will be delivered from embodies a thereof and causes the water trunnion 80. The

means, shown as centrlfugal pumps 100, is

provided for causing the passage of water i through these pipes.

The apparatus which I have thus far describedfis employed in operating upon pulp in thetfollowing manner.. c The pulp is taken as it comes from the digester in a loose semisolid condition and containing generally about 90 parts of Awater-chemical solution and this semi-solid mass is fed into the apparatus down the table 26 on to the conveyor 3.

The wet semi-solid mass moves along with the conveyor 3 until it is carried thereby into cooperation with the conveyor 2, whereupon both conveyors cooperate to vcompress the mass and feed it through the tapering mouth between the pressures rolls 23, 23a, 24, 24a, 25 and 25a. During its passage between said rolls, it is subjected to increasing pressures and a large percentage of the water therein is squeezed out so that the mathel last cooperating rolls 25 and 25a in the form of a relatively solid cake or web. The water which is freed in the manner described carries with it an appreciable part of the chemicals which enter into solution with the water. The Water freed from the under side of the material passes through the-cracks between the conveyor slats and falls into the trough 30. The Water freed from the upper face of the material is squeezed through the cracks between the slats of the upper conveyor on to the upper surface ofthe lower reach of such conveyor. A part of this water overiowsv throu h a by-pass pipe 77 into the trough 30, w ile the remainder of such water is picked up by the apparatus shown in Figs. 6 and 7 and delivered to the trough 30 through a pipe 78.

he apparatus shown in Figures 6 and 7 perforated lmetal cylinder' 79 to rotate freely on hollow trunnions cylinder 79 is covered with absorbmounted 80. The

1 ent material 81, such as soft felt which as it rolls over the conveyor acts as a blotter to suck upthe water. A hard surface roll 82 bearsagainst the felt coveri vg 81 at the top out through perforations in the circumference ofthe cylinder. This water falls into the interior ofthe cylinder and is caught in a basin 83, which communicates with a hollow pipe 78 is connected with a hollow trunnion, so .that the water thus gath- `torily.

ered is conveyed through the pipe 78 to the,

trough 30. This apparatus hasv been found in practice to give unusually satisfactory results, particularly in dealing with hot liquids where a pump would not operate satisfac- Apparatus such as shown in Figures 6 and is associated with each 'gang vof pressure 'Abe further diluted.l The y divided form and in a y reach 12 of the conveyor 5 `which deliver a third cake'or to be squeezedv the material` is rolls and an-overflow pipe' 77 `also cooperates therewith.

The solid cake or ribbon resulting from the first pressing operation is delivered from the conveyor. 3 y way of table 66 to the first shredder and washer 15. This shredder and washer thoroughly shreds the cake or'comminutes it while wash-water is shredder through ,a pipe 75. y Y The shredding and washing thus takes place in'the presence of further water in order that the chemical within the material may material is delivered from the shredder and washer 15 in efficiently wet semi-solid condition to the upper reach of the conveyor 10, which serves to carry the material into cooperation with the lower reach of the conveyor 3 and these conveyors collectively pass the material through Vthe second pressing operation to again form the material into a cake and simultaneously squeeze out the waterchemical solution into the trough 40. After leaving these'cond gang of pressure rolls, the material is delivered to a secondfshredder and washer 16 supplied with' water through .the pipe 74'and wherein a second shredding and washing operation with further dilution takes place. The material is delivered from 'the second shredder and washer on to the upper to be carried thereby between the third gang of pressure rolls, web to a third shredder and washer 17 and deliver the products Iof the further dilution to the tank 50.

The shredding and washing operations described are repeated in the apparatus 17 supplied with water through the pipe 73 and the finely divided pulp is thereupon delivered to the conveyor 6 to c throu h the fourth and last ressing operation, t

e aqueous product of w ich is received web is fed down the incline table 18 out of the'machine.

Particular attention is called to the fact that prior'to'each com ressing operation, a diluent is added and eac time the material is subsequently compressed, this diluent. is s ueezed out, carrying therewith a portlon o the chemical previousliyl7 contained in the pulp. In other words, eac time the material 1s washedand thereafter compressed, 1t 1s freed of a further portion of the chemical'so that by successive washings and pressinps,

finally freed of substantia ly all of its chemical content. In practice, I find it thoroughly practical to feed fresh water through the pipe 73 tothe last washer 17, whilethe washers 16 and 15 are supplied from the troughs and 50, respectively. This constitutes 1n effect a counter-current washin with thelast washin st Y utilizing fres water. Thig is a hig ye cient manner of fed to the simultaneously be passed. therewith treating the-material since a relatively small portion of fresh water is required' with consequently less water flowing from the trough through the pipe 84 for treatment to recover the chemicals.

Particular stress is placed on the fact that the oppration of treating the pulp is continuous, t e pulp being in the state of continuous movement fromthe time it enters until it leaves the machine. -Thus, I am able'to ob tain with a minimum supply of water a thorough washing with maximum speed and output. The pulp which is operated upon by the apparatus shown and described is of a very slippery nature which renders its comp-ression by rolls alone difficult. It is for this reason that the continuous cooperating conveyors are employed in conjunction with the rolls to efliciently feed the pulp through the pressure zones.

Each roll assembly has been illustrated as embodying three sets of cooperating rolls,

but a greater or lesser number may be used. Moreover, if desired, I mayemploy pressure roll assemblies of the character described and claimed in my Patent No. 1,764,456 of `J une 17, 1930, Fiber Board Machine, but such apparatus is not essential for the carrying out of the present method, it being particularly desirable here to produce a iushing or c1r culat-ion of the water through the material so that itwill entrain the chemicals and carry them off .in solution.

The foregoing detailed description sets forth the invention in its preferred practical form. It will of course be understood, however,

that a greater or lesser number of conveyors and washing device may be employed than shown without departing from this invention. For this reason and others, the invention is to be understood as fully commensurate with the appended claims.

The apparatus which I have described is -primarily intended for use in the removal of chemicals from pulp, but it may be used for other purposes without departing from this invention.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is: i

1. In'an apparatus of the character described, pressure means to compress pulp to Y free. the pulp from a quantity of its water content, means to thereupon shred and knead said compressed pulp and thoroughly commingle water therewith, and pressure means to receive the commingled pulp'and water,

scribed, means for shreddingand kneading and means for again compressing and again compress said pulp to again squeeze the water therefrom. 2. In an apparatus of `the character depulp and thoroughly commingling water therewith, means for compressing the .pulp prior to feeding it to the shredding means, the pulp to squeeze the water therefrom after it has been shredded and commingled with such water.

.` 3. In an apparatus of the character de-v scribed, means for squeezing water from pulp and simultaneously forming the pulp into a relation to one reach of the other, rollers positioned back of thecooperating reaches of said conveyors and coacting therewith to form between said cooperating reaches a compression mouth, means for actuating the conveyors to convey pulp through said mouth for the purpose of squeezing water out of the pulp and forming said pulp into a web, means positioned contiguous to the loutlet of said mouth to finely divide the web and miX water with the material thereof, and means for thereafter compressing said mixture of water and material to'squeeze the water from the material and again form the material into a web.

5. In an apparatus of the character described, a pair of cooperating conveyors positioned in superimposed relation with one reach' of each in spaced apart relation to one' reach of the other, rollers positioned back of the cooperating reaches of said conveyors and coacting therewith to form between said cooperating reaches a compression mouth, means for actuating the conveyors to convey pulp through said mouth for the purpose of squeezing water out of the pulp and forming tiguous to the outlet of said mouth to finely divide the webv and mix water with the material thereof, and a third conveyor positioned subjacent to and cooperating with one of the first mentioned conveyors,r rollerscoacting with cooperating reaches of these two latter conveyors to formbetween adjacent reaches thereof a second pressurev mouth through which the mixture of material and water is fed for the purpose of squeezing out the water from suchmaterial and simultaneously vforming the 'material'again into a-web.

6. In an apparatus of the character` described, apluralityl of superimposed conveyors positioned consecutively in staggered partially overlapped relation to form between contiguous reaches of the several conveyors pressuremouths adapted to compress-,pulp fed b` the respeotiveconveyors through said mout srollers positioned back, of and engaging with the contiguous reaches of the con- ,said pulp into a web, means positioned coni lll) the 'pulp as the pulp is carried through the pressure mouths. of the conveyors for the purpose of freeing the pulp from its chemical 5 content.

In'4 an apparatus of the character described, a plurality of superimposed, endless conveyors having openings therein for the passage of liquid therethrough and posi- "tioned consecutively in staggered partially overlapped relation to form between contignous reaches of the several conveyors pressure mouths adapted to compress pulp fed by the respective conveyors through said mouths,

` rollers positioned back of and engaging with the contiguous reaches ofthe conveyors at the mouths to subject the pulp to pressure while passing through the mouths, means for thoroughly wetting the pulp after its passage through one, mouth and priorto its passage through thenext mouth, whereby the water thus introduced-serves to dilute the chemical in the pulp and cause the water-chemical solution tobefsqueezed from the pulp as the pulp is fed through thepressure mouths for the purpose of freeing the pulp from its chemical content, and a suitable receptacle positioned to catch the water freed from the pulp at each compressing operation.

8. In an apparatus of the character described, a plurality of superimposed, endless slatted conveyors positioned consecutively in staggered partially overlapped relation to form between contiguous reaches of the several conveyors pressure mouths adapted to compress pulp ed by the respective conveyors through said mouths, rollers cooperating with the conveyors at the mouths to subject the pulp to pressure while passing through the mouths, shredding and washing means positioned between the outlet of each mouth and the inlet 'ofthe next mouth to receive the material dischargedyfrom each mouth land to shred it and thoroughly admix it with water before delivering such material to the-next mouth.

9. In an apparatus of Athe character described, a pluralityy of"superimposed, endless. conveyors having openings therein for the passage of liquld f therethrough and positionedfconsecutively in staggered partially overlapped relation to form between contiguous reaches of the several conveyors pressure mouths adapted to compress pulp fed by e respective conveyors through said mouths, rollers .cooperating with -the conveyors at lthe mouths to subject the pulp to pressure while passing through the mouths,qshredding .and

was g meanspo'sitioned between the outlet of each mouth and the inlet of the next mouth -to receive the material discharged from each it with water before delivering such material to the next mouth, said shredding and washpulp and causethe l' lng meanscomprising a plurality of toothed ro ls positioned within a suitable tank adapted to contain water, and means to revolve said rolls to produceupon the material a combination shredding and kneading action to bring 'l about a thoroughv admixture of the water withthe pulp.

l0. In an apparatus of the character del scribed, a plurality of conveyors positioned consecutlvely in staggered partially over- -lapped relation to form between' contiguous reaches of the several conveyors pressure mouths adapted to compress pulp fed by the respective conveyors through said mouths, rollers cooperating withthe conveyors at the mouths to subject the pulp to pressure while passing through the mouths, shredding and washing means positioned between the o'utlet of each mouth and the inlet of the next mouth i to receivey the material discharged from each mouth to `shred it and thoroughly admix' it with water before delivering such l material to the next mouth, said shredding and washing means comprising'a plurality of toothed rolls positioned within a suitable tank adapted to contain water, and provided with teeth projecting beneath the teeth of the rolls, and means for rotating the rolls to shred and knead the pulp between the cooperating teeth ofthe rollers and tank and to form a thorough the shredded 11. In an scribed, a pa1r of cooperating endless conveyors provided with openings through which liquid ma pass and positioned with one reachof eacli in spaced relation to one reachof the other, rollers positioned back of each of said cooperating reachesof the conveyors andl coacting therewith to form between said reaches j through which material is adapted to be fed to squeeze liquid from the material and cause it to flow through veyors to the back surfaces of said conveyors, and means for removing such liquid from the pulp,

back surface of one of the conveyors, saidmeans embodyin ign relatively so ed to bear against water therefrom,

a perforated cylinder havabsorbent covering adaptthe conveyor and suck up a roll bearing against said absorbent covering for squeezing the liquid through the perforations 1 the openings of the conmixture of the water and apparatus of the character de- 'i a compression mouth scribed, a pair of cooperating conveyors posi` l tioned with one reach of each in spaced apart converging relation to one reach of the other;

means supportmg and 'ding said reaches to formv between said reac esa converging cornpression'mouth through which material 1s adapted to be fed to squeeze liquid therefrom, l

and means positioned in advance of the compression mouth `to shred. and wash pulp and deliver it to one of the conveyors in advance of the compression mouth.

' In testimony whereof I have signed the foregoing specification.v

OTTO MANTIUS.

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