US2916216A - Method and apparatus for preparing paper making stock - Google Patents

Description

Dec. 8, 1959 N. A. ALTMANN ETAL 2,91

METHOD AND APPARATUS FOR PREPARING PAPER MAKING STOCK Filed July 25. 1952 2 Sheets-Sheet 1 INVENTORS. NmmmzJQZZmmz/ B/WdZzcU/zfi. Bureau, VW a/Z Dec. 8, 1959 N. A. ALTMANN ETAL 2,916,216

METHOD AND APPARATUS FOR PREPARING PAPER MAKING STOCK Filed July 25. 1952 2 Sheets-Sheet 2 METHOD AND APPARATUS FOR PREPARING PAPER MAKING STOCK Norman A. Altmann, Wilmette, and William H. Bureau,

Glen Ellyn, Ill., assignors to Butler Company, Chicago, 111., a corporation of Illinois Application'July 2'5, 1952, Serial'No. 300,938

, 4 Claims. (Cl. 241-20) This invention relates to an improved method of preparing paper making stock derived from waste printed papers of various types, digested and cooked native pulp, and the like, and to an improved apparatus for carrying out the'method. By practising the improved method the stock is brought readily and rapidly to a very clean ample, waste printed newsprint or magazine paper, is.

preliminarily disintegrated in a water bath to producea slurry, and then is subjected to vigorous hydraulic agitation, with resultant further dispersion, or reduction in concentration, of the fibers in the watery-slurry. This is followed immediately by. mechanical. screening, as the result of which impurities, ink particles, particles of coating material, etc., which have been dislodged from the fibers in the disintegrating. operation and kept in water suspension during hydraulic agitating and scrubbing, are separated from the fibers by an action analogous to that of washing.

It is an object of the invention to provide a paper preparing method, along with apparatus to realize the same as described above, which is very inexpensively performed by reason of its elimination of the use of chemicals and which offers low initial equipment cost and insignificant cost of maintenance, yet which has a high output rate.

Yet another object is to provide such a method comprising steps of extensive fiber disintegration in water to form' a slurry, violent agitation and dispersion of the slurry by the sole action of high velocity water jets, and

a final fiber screening operation, in which the interme-- diate agitating operation has the effect of violently scrubhing the fibers to remove foreign particles not dislodged by the initial disintegration, and of also maintaining is accomplished by the action of small high velocity jets of water discharged at intersecting angles into a body of the slurry, accompanied by a continuous discharge of a Wide, shallow stream of deconcentrated slurry over a flat inclined screening surface, by which the ink par-- ticles and other foreign matter are rapidly screened off, the clean fibers being gravitationally collected after tumbling down the screen, for processing. in a conven tional paper making machine.

Still more specifically, it is an object of the invention to provide fiber scrubbing and agitating apparatus of the foregoing character which is devoid of moving parts, hence very inexpensive and requiring. no maintenance or servicing, the apparatus including a closed agitating and United States Patent 2,916,216 Patented Dec. 8, 1959- scrubbing chamber through which preliminarily disintegrated paper fibers in an. aqueous bath or slurry are continuously circulated, while being subjected to hydraulic agitation by a multiplicity ofhigh pressure water jets directed from different angles; these jetsbeing; primarily responsible for the circulation of the slurry, aswell as the violent thorough agitation and: reduction thereof to a much more dispersed,- less concentrated fiber content; the chamber. having a discharge throat or passage of relatively wide, fanned out shape through which the dispersed slurry flows in the form of a shallow stream onto a screening device immediately adjacent the chamber throat.

The foregoing statements are indicative in a general way of the nature of the invention. Other and morespecific objects will be apparent to those skilled in the art upon a. full understanding of the construction and operation of the method and apparatus.

A single embodiment of the invention is presented herein. for purpose of illustration. It will be appreciated that the invention may be incorporated in other modified" forms coming equally within the scope of the appended claims.

In the drawings:

Fig. l'. is a fragmentary view in side elevation illustrating an improved apparatus for performing the operations involved in theimproved method;

Fig. 2 is a fragmentary top plan view of the apparatus;

Fig. 3 is. a somewhat enlarged, fragmentary view in vertical central sectionthrough the apparatus, being taken along a line corresponding generally to line 3--3 of Fig. 2; and

Fig. 4 is a fragmentary view in cross section along the" line 44 of Figs. l and.3.

Present day paper making stock, derived to a great extent from waste papers of different types, is ordinarily prepared by mechanically disintegrating the waste paper, and cooking the same at elevated temperatures in a chemical de-inking and/or defibering bath for the purpose of loosening and dissolving inks, pigments, coating materials, etc. from the waste paper fibers. These reclaiming operations are expensive, due to the costly chemicals and time and labor involved. Furthermore, the-native pulp fibers are substantially darkened by cooking, hence requiringv bleaching. Extensive washing; of' the fibers is always necessary, in any event, in order to free them from the chemical agents in which they have been treated. All this greatly increases the cost of the reclaiming operations necessary to prepare the fibers for paper making.

The invention provides an improved method and apparatus whereby cooking in chemical agents at elevated:

temperatures and repeated washings, bleaching, etc., are

eliminated. The: waste paper fibers are readied for thepaper making. process by three simple successive operations. The method and apparatus are also suited to the treatmentof digested and cooked native pulp, as well as:

reclaimed stock.

Referring to drawings, the reference numeral 10 generally designates. an improved fiber scrubbing, agitating and dispersing unit according to the invention. This is supplied with liquid pulp or waste paper slurry through a forward intake fitting 11 to which a pipe 12 is connected. Unit 10 comprises an enclosed, generally U-shaped metal. housing 13 which may be supported by appropriate legs 14 on an elevated platform 15 of any suitable type. Housing 13 has vertical side walls 16, a rearwardly and upwardly inclined bottom wall or floor 17, and a semicircular? rear wall 18 merging at its bottom and top with the floor and with: a forwardly and downwardly inclined top housing wall 19. 7

Lower intake and upper discharge legs 20, 21, rc-

3 spectively, for the U-housing 13 are defined by the housing walls and by a forward V-shaped plate member, generally designated 22. A forwardly and upwardly inclined upper surface 23 of this plate converges with respect to the top housing wall 19 of the housing, defining a forwardly narrowing discharge throat 24 of uniform horizontal width. The lower surface 25 of V-member 22 parallels floor 17 of the housing. Member 22 is coextensive in width with the housing, and is sealed at its opposite ends to the side walls 16 of the latter to define a U-shaped housing structure. Intake fitting 11 is applied to a rectangular wall 26 which otherwise seals the intake leg 21 at the forward intake end of the housing.

It may be found desirable to provide an inspection opening to the interior chamber of the housing; in the illustrated embodiment such opening is provided by an upstanding rectangular chimney member 27, which extends upwardly-from a rather large, like shaped aperture at the junction of the rear and top walls 18, 19 of the housing. A removable closure member 28 may be applied to the chimney, if desired.

In order to laterally confine the stream of relatively thin watery slurry issuing from the discharge throat 24 of the housing, we provide vertical side fences or walls 29 extending forwardly and downwardly at either side of and above the housing. This wall is well'fiared out laterally at 30 (Fig. 2) to enable sidewise spread of the stream which issues through dischargethroat 24. The body of liquid slurry in housing 13 is agitated with great turbulence as the same traverses the housing from intake fitting 11 to discharge throat 24. This agitation is performed solely by hydraulic action. As illustrated best in Fig. 3 of the drawings, housing 13 is provided With a number of transversely extending horizontal jetting tubes which emit high velocity water jets S to the housing chamber. One of these, designated 32, is applied to a full length opening at the junction of forward Wall 26 and floor 17, being in liquid tight relation to the housing. Tube 32 is perforated to provide a plurality of small radial jet orifices 33, these being aligned in longitudinally spaced relation along the tube. Water is supplied through a supply line 34 to one end of tube 32 under a relatively high pressure.

Similar jetting tubes 35, 36, 37, 38 all beneath the normal level 'of the slurry in the chamber, are fitted into appropriate apertures in the upper wall 25 of the V-member 22 defining housing intake leg 21, these tubes being likewise provided with radial jetting orifices 33 like those of the tube 32, and similarly spaced longitudinally of the respective tubes. Tubes 35, 36, 37, 38 are fed from a manifold pipe 39 which is in turn supplied with water at a pressure mentioned laterby a feed line 40.

A still further submerged jetting tube 41 is fitted in the upper wall 23 of housing V-member 22, being provided with series of jetting orifices 33, as in the case of the other jetting tubes. If desired, still further jetting tubes identical to those described may be applied to the housing; an example is the tube 42 on the arcuate rear housing wall 18 referred to above. Supply lines 40 service the jetting tubes 41, 42, it being understood that jetting occurs at all tubes under uniform pressure. Suitable provisions not necessary todescribe connect the various pressure lines 34, 40 and 40' with a source of water at relatively high pressure, say 50-300 p.s.i.

The arrangement of the various sets of jet orifices 4 however, we find that the approximate arrangement shown in Fig. 4 is effective.

The angular disposition of the orifices, in respect to the direction of the water jets S emitted therefrom, is of considerable importance in accomplishing the desired turbulence. As shown in Fig. 3 of the drawings, jets S issuing from tubes 36 and 37 intersect those from tube 38 at an acute angle, while the jet from forward bottom tube 32 intersects all three sets of these, flowing rearwardly and at a slight upward angle, with reference to the entry flow of slurry from supply pipe 12. The jets from tube 35 generally parallel those from tube 38, being in obtuse intersecting relation to the jets of tube 32, while. the tube 42 has its orifices 33 arranged to direct downward and forward jets S in intersecting relation to those out of tubes 32 and 35.

The arrangement of radial orifices 33 in the throat jetting tube 41 is important. They are disposed so that a rearward stream S issues in direct opposition to the path of flow of slurry forwardly to discharge throat 24. This insures a final vigorous agitation of the now considerably dispersed and thinned slurry as it issues from the housing, keeping ink particles and other particles of foreign matter in liquid suspension until the flow passes onto a forward continuation 43 of the surface 23.

In issuing forth onto floor extension 43, the relatively shallow stream spreads out, though laterally confined by the members 29, 30, and gravitates down an acute angled ramp 44, which is in superposed, longitudinally overlapping relation to a screening device 45 (Figs. 1 and 2 of the drawings). Device 45 includes a fine wire'screen 46 (70-80 mesh) which is suitably supported by appropriate framework 47, for example upon the platform 15 which mounts scrubbing and agitation unit 10.

Screening device 45 may consist of but a single screen, or it may be in the form of a plurality of screens arranged in cascaded relation, in a manner Well known to the art. The scrubbed fibers tumbling thereover are collected at the bottom of unit 45, particles of foreign matter and ink particles being water carried through the interstices of the screen. The collected fibers are generally sufiiciently washed after a single run through unit 10 to be charged directly to a paper making machine for the production of a very bright sheet; however, a second run may be made if desired. It will thus be appreciated that the method of the invention is exceedingly economically performed, there being no chemical or cooking cost involved and the apparatus required for the performance thereof involving the ultimate in simplicity and ease of operation.

In practising the improved method, waste paper is preliminarily disintegrated and pulped in a suitable apparatus well known to the art, such as a conventional beater or a refiner of any oneof various types. This is done, without chemical treatment, in a water bath or carrier preferably substantially below room temperature, i.e. at 5070 F. As described in our copending application Serial No. 263,965, filed December 28, 1951, now abandoned, we have found that disintegration at relatively low temperatures, as compared with known cooking treatments, promotes shattering of ink and other particles in the mechanical grinding operation, and also increases the surface tension of the water.

The resultant watery slurry is transferred directly, as by pumping through supply pipe 12, to the inner chamber of housing '13. Here it is violently agitated by high velocity jets submerged in the slurry in the manner described above, while at the same time being considerably thinned or dispersed by the added water of the jets. The fiber slurry proceeds, under such agitation, around the U-turn of the housing chamber and approaches discharge throat 24. Here it is given a final violent agitation by the jets S from tube 41. Issuance of the liquid from the housing is followed by screening and separation of foreign matter, as described above.

The temperature of the water used in jetting is preferably relatively low, certainly not in excess of room temperature. In short, the water may be at a temperature falling within the same range as that used in the preliminary disintegrating operation, since it is contemplated that the source of this water shall be the same as any other water used in the paper making operation, for example, a river or a water main.

The amount of water required in operation of the apparatus is not excessive and the output rate of the apparatus is high, being controlled largely by the hydraulic pressure in the jetting tubes, the number of tubes, the number of tube orifices, etc. As stated, the pressure may range from 50 lbs. per square inch to 300 lbs. per square inch, however, as far as we are able to ascertain, these values do not appear to be critical, other than in respect to the output rate of the unit. Quite obviously, if the pressure falls below a minimum necessary to keep foreign matter, ink particles, etc. in suspension, they will tend to redeposit upon the fibers, with resultant loss of operational effectiveness.

We claim:

1. Apparatus for dispersing the fibers in a slurry of wastepaper pulp and stripping ink particles from the fibers, which comprises, a generally U-shaped chamber, a slurry inlet adjacent the outer end of one of the legs of said chamber, a narrow outlet opening extending across the outer end of the other leg, and Wash water distributing means located in opposite walls of said chamber having spaced jet openings on the interior of said chamber whereby as a slurry of wastepaper pulp is flowed in a U-shaped path through said chamber it may be subjected to high velocity jets of wash water introduced therein under pressure from said jet openings.

2. Apparatus for dispersing the fibers in a slurry of wastepaper pulp and stripping ink particles from the fibers which comprises, a generally U-shaped chamber having parallel side walls and adapted to be supported with one leg overlying the other, a slurry inlet adjacent the outer end of the lower leg of said chamber, a narrow outlet opening extending across the outer end of the upper leg, and wash water distributors extending across the inner and outer U-shaped walls of said chamber having spaced jet openings communicating with the interior of said chamber whereby as a slurry of wastepaper pulp is flowed in a U-shaped path through said chambers it may be subjected to high velocity submerged jets of wash water introduced thereinto under pressure from said jet openings.

3. Apparatus for dispersing the fibers in a slurry of wastepaper pulp and stripping ink particles from the fibers so as to condition the slurry for separation of the ink particles from the fibers, comprising, a U-shaped chamber having vertical and parallel side walls, means for supporting said chamber on its side with one leg overlying the other, the lower leg being substantially deeper in cross section than the upper leg and having a slurry inlet located adjacent its outer extremity, the outer end of said upper leg terminating in a narrow outlet opening extending across the width of the chamber, an apron joined to the bottom lip of said outlet opening for receiving slurry discharged therefrom, and wash water distributors extending across the inner and outer U- shaped walls of said chamber having spaced jet openings communicating with the interior of said chamber whereby as a slurry of wastepaper pulp is flowed in a U-shaped path through said chambers it may be subjected to high velocity submerged jets of wash water introduced thereinto under pressure from said jet openings.

4. The method of processing a slurry of wastepaper pulp which has been subjected to a disintegrating action to defiber the wastepaper and dislodge ink and other particles from the fibers, comprising, subjecting an enclosed stream of said slurry of relatively deep cross section to the action of a plurality of high velocity submerged jets of wash water so as to intensely agitate the slurry and disperse the fibers and said particles in the water vehicle while lowering the consistency to a thin watery slurry, and immediately discharging the thin watery slurry onto a screen and draining the water and suspending particles from the fibers so as to leave them in a clean condition.

References Cited in the file of this patent UNITED STATES PATENTS 955,990 Petsche Apr. 26, 1910 1,026,577 Hahle May 14, 1912 1,026,578 Hammond May 14, 1912 1,399,184 Billingham Dec. 6, 1921 2,641,164 Hill et a1 June 9, 1953

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