CA1161011A - Board sorter - Google Patents
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- CA1161011A CA1161011A CA000358277A CA358277A CA1161011A CA 1161011 A CA1161011 A CA 1161011A CA 000358277 A CA000358277 A CA 000358277A CA 358277 A CA358277 A CA 358277A CA 1161011 A CA1161011 A CA 1161011A
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- screen
- set forth
- paper
- impeller
- papers
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21B1/00—Fibrous raw materials or their mechanical treatment
- D21B1/02—Pretreatment of the raw materials by chemical or physical means
- D21B1/026—Separating fibrous materials from waste
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Paper (AREA)
Abstract
BOARD SORTER
ABSTRACT OF THE DISCLOSURE
Apparatus for separating mixed paper qualities especially laminated products such as corrugated cardboards comprises preconditioning the product with a solvent to mollify the adhesive bond, exposing the preconditioned laminate in a mill to procure delamination and selective fragmentation of the constituent plies of the product. The mill comprises an impeller enclosed by a screen through which fragments pass for collection, and a wiper for unclogging the screen.
ABSTRACT OF THE DISCLOSURE
Apparatus for separating mixed paper qualities especially laminated products such as corrugated cardboards comprises preconditioning the product with a solvent to mollify the adhesive bond, exposing the preconditioned laminate in a mill to procure delamination and selective fragmentation of the constituent plies of the product. The mill comprises an impeller enclosed by a screen through which fragments pass for collection, and a wiper for unclogging the screen.
Description
~L~6~
BOA~D SO~ER
I~Lis invention broadly relates to the treatment of waste papers. It particularly relates to the separation of differing grades of paper frcm mixed waste papers. Still more particularly it relates to apparatus and method for the separation and recovery of different paper grades comprising composite laminated pap~r products.
The ccmposite laminated paper product of most concern herein because of its widespread use in ccmm~rce and the con-sequent large volume thereof available for recuperation and salvage is corrugated board, otherwise known in the art as corruyate.
Cor~gate of the most simple construction consists of two q~allta-tively distinct ca-te~ories of paper, wherein a corrugated medium is sandwiched between and adhered to opposed layers of linerboard.
cc~prised principally of long softwood (kraft) fibres and exhibits a relatively high tensile strength. The medium is cc~prised principally of short, hardwood semi-chemical fibres and exhibits a relatively high compression strength but low tensile strength.
It is now well known that significant economic advantages may be gained from the recycling of waste paper, .~ ~
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BOA~D SO~ER
I~Lis invention broadly relates to the treatment of waste papers. It particularly relates to the separation of differing grades of paper frcm mixed waste papers. Still more particularly it relates to apparatus and method for the separation and recovery of different paper grades comprising composite laminated pap~r products.
The ccmposite laminated paper product of most concern herein because of its widespread use in ccmm~rce and the con-sequent large volume thereof available for recuperation and salvage is corrugated board, otherwise known in the art as corruyate.
Cor~gate of the most simple construction consists of two q~allta-tively distinct ca-te~ories of paper, wherein a corrugated medium is sandwiched between and adhered to opposed layers of linerboard.
cc~prised principally of long softwood (kraft) fibres and exhibits a relatively high tensile strength. The medium is cc~prised principally of short, hardwood semi-chemical fibres and exhibits a relatively high compression strength but low tensile strength.
It is now well known that significant economic advantages may be gained from the recycling of waste paper, .~ ~
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10~
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including corrugate, and if the ~JaSte to be recycled -- i.e. the "furnish" -- is ccmprised of mixed papers, it is ~urther known that such economic advantages may be enhanc~d, often to a considerable extent, by sorting the various papers com~rising the furnish according to their respective qualitative categories insofar and to the e~tent it is feasible and possible to do so prelimunary to the actual recycling thereof.
This expedient avoids or minimizes admixture of various paper grades in any one recycling operation which would usually relegate the recovere~ produst to a relatively inferior and, hence, cheaper re-use. Conversely, pre-sorting of the paper makes it possible for the better grades to be sep~ra-ted and recycled separately from the lesser grades and, hence, thereafter ` used in superior and resultantly m~re valuable applications.
In U.S Patent 4,124,168 is~sued Nove~ber 7, 1978 and co~nonly assigned herewith there ls described appaAratus and rnethod for sorting mixtures of papers of different grades. I'he method comprises exposing the dry paper components contemForaneously to a milling operation wherei~ the components are churned whilst avoiding cutting so as to selectively fragment the weaker c~nponents which are retrieve~ by passage through an enclosing screen. It will be apF~rent that slAch metho~ is unsuited for the - separation of corrugate, per se, as the physical nature thereof preclL~es the weaker component, ie the medium, from ~xposure to ~ 25 the selective frasmenting forces.
'; Various methods have been heretofore proposed for , ~ 3 ~ ~9602 P/5CI~
recovering corrugate. Such methods usucally comprise an initial step of breaking the adhesive bond between the liner~oard a~d the medium; subsequent steps to sort and separately recover the liner board an~ medium depo~ largely upon the nature of the initial step. In a first propo5al) small pieces of corrugated bcard are thoroughly mixed with a large excess of water, beaten under high energy conditions to form an all fibre slurry from which fibre qualitiès are reported to be separately recovered by centrifuging. - In a still further - 10 metho~ small pieces of corrugate are treated with limited quantities, in the range of about 20% to about 50% by welght, based on the weight of paper furnish, of a debonding liquid comprising a debonding agent dissolved in a suitable liquid vehicle therefor so as to separate the laminae in an essentially dry state. It appears that it may be necessary to pretreat the furnish thermally prior to contacting with the debonding liquidO
It is possible that corrugate furnish treated in this matter would be separable in the apparatus of aforementioned patent ~,124,168 and in accordance with the method described therein.
In my copending application Serial No. 343,875 filed January 17, 1980 and titled "Method and Apparatus for Preconditioning Laminated Paper for Recycling", c~nm~nly assigned herewith there is di æ losed a method generally inte~nediate the above extre~es whereby corrugate is contacted by a suitable solvent, generally water,to which may be added a ~nall quantity of wetting agent. Contacting is suitably carried out in a bath . . .
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with paddles which sl~ merge the corrugate and propel it through the bath to provide a suitable residence time wnereby the water pick up is generally such that the m.oisture content of the corrugate emerging from the bath is usuallv at least a~out 50%
by weight. '~he adhesive bond between the liner and medi~n is llified and weakened by s~ch treatment wh~reby it is relatively easy to delaminate the corrugate; it is not believed that the delamination and sorting thereof to selectively recover canponent paper qualities 'nas been heretofore realized on a connercial basis.
It is a primary object of my invention -to provide a methcd for the separation and recovery of paper qualities from laminated papers.
It is a further object of my invention to provide a comnercially viable method for the separation and recovery of paper qualities from laminated papers.
It is a still further object of my invention to provide a methcd in accordance with the foregoing for the separation and recovery of linerboard fractions of gocd purity ar~ yield fran corrugate.
It is yet another object of my invention to pxovide appara-tus consonant with the achievesnent of the foregoing objects.
In accordance with one aspect of my invention, an apparatus for separating and recovering muxed papers comprises a mill including a screen and an impeller embraced thereby to chlrn and axially advance the papers in the mill and procure their selective fragmentation and the discharge of paper fragments through the screen, and unclogging ~eans for dislodging paper fragments trapped in the mesh of the screen during the milling ~GlOi~
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operation.
In accordance with a` presently preferred aspect of the invention, the screen is tubular and rotates about its longitudinal axis, so as to bring portions of the screen to the proximity of the unclogging means, In accordance with anot~er presently preferred aspect of of the invention, the unclogging means is formed by a wiper dis~osed in close prcximity to the screen and rotating relative thereto. It is still further preferred that the unclogying means extend substantially the full length of the screen, and m generally parallel proximity thereto. Means may optionally be provided for varying the proximity of the unclogging means to the screen. The wiper, which may be in the form of a bnlsh, the bristles (which may be of any convenient material) of which may then be brought into contact with the screen so as to wipe the screen and rernove okdurately clinging material there-from, or be slightly spaced the~efrom so as to remove paper clinging to the .screen by mechanical contact with the paper or by entraining the paper in air currents generated by the rotating brush, and for this purpose the bnlsh may be constructed so as to generate desirable air currents.
In accordance with yet another preferred aspect of the invention the mill includes a hopper for feeding paper values into the screen enclosure, and a distributor is provided to intercept papers delivered to the nu`ll and generally break up clumps and distribute the paper around the impeller adjacent the screen inlet.
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It is presently preferred that the dis-tributor com2rises a radial propellor which acts to create an axial air flow through the mill, and entrain and distribute the paper feed in the air current. It is also presently preferred that the impeller comprise radial fins spaced thereakout an~ inclined in generally spiroid form w.ith respect to the longitudinal axis of the ~npeller 50 as to advance the papers through the ~ill, as earlier spoken of, and also to generate and supplement the axial air current generated ; by the distributor.
In accordance with another broad aspect of my invention, a method is provided for delaminating and recovering separately different paper qualities comprising different plies of a laminated ' ~ paper product. The metl~d ccnprises ap~lying a solvent to the laminated paper product to Frecondition it for delamination, of feeding the preconditioned laminated paper into a ~ill in which the paper is churned between an ~mpeller and an enclosing screen to procure the delaminatiQn and progressive fragmentation of the respect.ive plies whilst subjecting the screen to unclogging treatment to dislodge paper fragrnents trapped or otherwise retained thereon. In accordance with a further broad aspect of my invention, a method is provided wherein the churning is effected in a relatively clear and unobstructed churning zone between the im?eller and successive portions of the screen successively and cyclically presented in ~his zone, the successive screen portions being subjected to the - 7 - B9602 P/5 C~
unclogging treatment before its presentation in the zone, -rn accordance with the foregoing the unclogging treatment may ccmprise a simple mechanical action as by wiping, wherein the screen itself is wiped, as w~uld ~e indicated where clogging of the screen is particularly troublesome. Unclogging treatment may be less vigorous where indicated and comprise wiping of paper fragments which project through the screen and are trapp2d ; on the mesh thereof. Whilst the wiping may be carried out by the mechanical contact, it may also include the use of fluid currents, particularly air currents, which may be generated by a rotating wiper.
The method is unexpectedly advantageous particularly as applie~ to corrugate in that exposure of the corrugate to aqueous solvents for the purFose of mollifying and dissolving the adhesive bond between the-lamlnae has the further effect of decreasing the strength of the weaker component, ie the medium, to a proportionately ; greater extent than that of the stronger component, t~e lLnerboard.
In part this is due to the different nature of the ~ibres comprisincJ
the two c~alities of paper. It will be appreciated however that the linerboard component of corrugate i5 generally treated with size, and that such treatment reduces the rate at which water is imbibed by the liner. The medium is not usually treated in this manner, ancl the rate of water imbibition is greater t~an that of the linerkoard. In ccmparison to the method of aforementioned U.S. Patent 4,124,168, for sorting relatively dry mixtures of paper qualities, the forces for procuring the fragmentation of ~61~
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the weaker paper qualities may be s~what reduced herein due to their mechanically weakened state. It is observed in a properly progra~mel m;ll that the fragmenting forces of reduced strength have relatively little capacity to fragment the stronger linerboard component, and the power utilization of the instant method is appreciably lower per unit output. It is further observed that there is a more efficient transfer of energy between the rotor of the mill wherein the fragmentation is to be produced and the wet furnish therein than is normally achieved when using dry furnish, due to the increased density of the wet furnish, again leading to decreased p~wer require~ents.
It should be understood that whilst in the specification I speak generally of recovering separately paper qualities from laminated paper products, the apparatus and method of this invention will not necessarily be applicable to all laminated paper products as are presently known and as may be known in the future. The suitability of the method and app~ratus may be gauged by a simple test to be subsequently revealed herein.
My invention will be further explained in relation to ~0 the following description of a preferred embodiment thereof. Such description is for illustrative purposes only and should not be taken as keing limitative of the broad aspects of my invention.
IN THE DRAWINGS:
FIG. 1 - shows a ~11 constructed in accordance with the invention in perspective viewj partially broken away to reveal interior detail;
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FIG. 2 - shows the mill of FIG. 1 m side elevation partially in section;
FIG. 3 - is a view on line 33 of FIG. 2;
FIG. 4 ~ shows an impeller fin in plan view;
FIG. 5 - is a view on 5-5 of FIG. 4, and FIGS. 6 and 7 - relate to testing and preconditioning of furnish for the mill.
Referring now particularly to FIGS. 1 to 3, a paper sorting mill is represented therein generally by the numera1 10 and comprises a supporting framework 12 and a generally i~permeable housing 14. An im~eller 16 is mounted for rotation with shaft 18 journalled in bearings 20 located at opposed ends of the housing. Shaft 18 is driven through pulleys 22 by motor 24 to rotate in a first direction, here shown as clockwise, as viewed from the left hand end in FIGS. 1 and 2.
Impeller 16 is embraced by a screen 26 of stout wire which serves to retain the paper furnish within mill 10 whereby it is acted upon to delaminate and fragment the furnish selectively. The mesh openings of screen 26 are dimensioned to permlt sift~lg of paper frag~ents through the screen for collection.
Screen 26 is secured to c~nd supported by runners 28 at each e~d thereof which are rotatable on trunnions 30 secured to framework 12. Means (not shown) are provided to rotate screen 26 slowly and preferably in the contrary sense to the rotation of i~elIer 16.
Screen 26 is strengthened by securing axially aligned straps 31 to the oNtside thereof extending between op~osed runners 28. Further straps, ~hich are not here seen surroNnd screen 26 for strengthening ` Furposes.
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Intermediate runners and trunnians ~ay also be provided for the pur~ose of additionally supporting screen 26, Impeller 16 includes a drlml 32 supported from shaft 18, and a plurality of f~ns 35 comprising blades 33 secur~d to the surface of the drum through the intermediary of mounting plates 34 The under surface of mounting plates 34 is axially grooved along the length thereof at 36 whereby mounting plates form saddles which sit securely on the arcuate surface of drum 32 when aligned with the axis thereof. The rno~nting plates 34 are secured to drwm 32 by bolts passing through openings 37 to form a plurality of axially aligned rows 38. Fin blades 33 are attached to saddle mounting plates 34 by welding at 39 to inter-sect the axis of the saddle mounting plate at the desired spiroid angle, generally in the range of about 15 to about 30, with 22 ~eing preferred for sorting wet papers, The adjacent ends of fin-blades 33 in a row 38 are in overlapping relationship.
Diagonally adjacent fin blades 33 are generally in spiroidal relationship. It will be appreciated that in accordance with this arrangement the fin blades 33 are planar and generally rectangular, as are r~cunting plates 34, thereby sumplifying the construction. ~lso it is relatively simple rNatter to replace the fins 35 so as to change the spiroid angle as may be desirable in accordance with a particular program for sorting a specific furnish. Of course, I do not preclude the use of arcuately shaped fins 35 or other alternati~e arrangements, particularly where other ~ans are used to advance the furnish in mill 10~
Mill 10 includes an inlet chute 40 having a throat 42 ~ B9602 P/5 C~
connecting the chute to the space enclosed by screen 26. Within chute 40 there locates an eiyht bladed radial propeller 44 secured to shaft 18 and driven therewith. The blades 46 of propeller 44 are pitched in the same direction as fins 35, each blade abutting to a fin, although the angle of pitch of the blades are preferably greater than that of the fins, generally a value in the range of about 30 to 45 having been found to be sultable. In operation,to be further described herein, substantial quantities of air are propelled through mill 10 by propeller 44 and also fins 35 acting in conjunction therewith. me ingress of air is desirably solely through inlet chute 40 via throat 42, and the egress of ~;r is desirably solely through air outlet opening 48 located at the axial end of mill 10 remote frcm chute 40. Cther points of likely ingress and egress are grossly sealed wi-th suitable flanges and covers as generally illustrated.
Impeller 16 is embraced by screen 26, the fins 35 of the impeller being suitably spaced from the screen so as to - procure a scrubbing action on paper furnish entrained between the fins and the screen and the selective fragmentation of the furnish thereby. The interior Æ face of screen 26 is generally devoid of elements that w wld coact closely with fins 35 to cut the feedstock as such cutting action is inimical with selective fragmentation. Ctherwise expressed, there is provided a relatively clear and unobstructed churning and scrubbing zone between the impeller and screen. The fragments of paper formed within m~ll 10 are removed from the action of impeller 16 by siev~ng through the mesh of cree 26 for colleotio . It is .
' found that when the screen 26 and impeller 16 are coaxially moun-ted, paper fragments are expelled about the whole periphery of screen 26. It is des~rable to limit the passage of paper fragments through screen 26 in at least one area thereof where there is positioned a screen unclogging means to be described, so as not to interfere unduly ~ith the unclogging-means. For ; this purpose I locate impeller eccentrically with respect to screen 26, preferably as shGwn by locating the axis of the im~eller shaft 18 beneath the axis of screen 26. The clearance between fins 35 is thus at a maximu~ at superior portlo~s of the screen, and the quantity of paper fragments passing through the screen in the zone is correspondin~ly at a mumLmum, hence it is here that I prefer to locate the unclogging means. Since the screen 26 rotates about its axis to move cyclically between the churning zones and unclogging means, successive portions of the screen are subjected to unclogging treatment before being re-presen-ted to the churning and scrubbing ~ and sieving zone.
; Impenmeable housing 14 includes a first end wall 50, locat~d generally in the plane of the inlet Openlng of screen 26, and a second end wall 52 located adjacent the end of the impeller adjacent air outlet opening 48 so as to generally surround the screen; In the instant embodiment a plurality of transverse partition walls 54, 56 and 58 through which screen 26 passes are shown axially spaced along mill 10, with partition walls 58 locating generally in the plane of the ou~let opening of screen 26, so as to divide mill 10 mto a number of co~ cb~ents.
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The ]c~er portion of each cc~partment forms an ou-tlet hopper, respectively numbered 60, 62, 64 and 66. A rotary outlet feed 67 is located in the base of each hoEr~er so as to generally seal the outlet in conjunction with the pa~er fragments normally contained in the hoppers.
An unclogging means is provided for cleaning screen 26 and here c~nprises a brush 68 extending substantially the full length of screen 26. Brush 68 has its axis generally parallel to the axis of screen 26, and is mounted to be rotatable by motor 70 so as to move relative to the surface of screen 26.
An arcuate slot 72 centred on the drive shaft of motor 70 is cut in end wall 50, a similar slot (not seen) being cut in partition wall 58 to permit adjustment of brush 68 radially with respect to screen 26 by any convenient mechanism, typically a screw mechanism. Brush 68 locates adjacent the outer surface of - screen 26 an upper quadrant of mill 10, a position in the - range of about 30 - 60 from the vertical axial plane of screen 26 being preferred. A second unclogging means is further shcwn here comprising a compressed air conduit 74 generally coextensive with screen 26 having a plurality of jet openings 76 therein disposed to be directed towards the screen, this second unclogging means also being located adjacent screen 26 in an upper quadrant of mill 10.
The general arrangement of a specific embo~lme~t of the -~ 25 apparatus having been described, the operation thereof will be discussed.
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TESTING AND PRECONDITIONING OF FIJ~NISH
San~le strips 150 n~ by 15 ~ are cut frcm the furnish, where this is corrugated the major dimension being perpendicular to the flute channels. The strips are immersed in a suitable solvent to mollify, dissolve or otherwise weaken the adhesive ~ond between the laminae and withdrawn at time intervals and the resistance to delamination measured on an INSTR~N tester within 1.5 minutes of recovery frcm the solvent.
The resistance to delamination of corrugate is taken as the average force reguired to rupture the bond between crests of the n~dium and the lin~rboard. The furnish is generally considered to be amenable to efficient sorting in a mill such as mill 10 when the delamination occurs substantially at the interface of the laminae with a resistance measured in the test of about 60 grms. Where the delamination is accompanied by indiscriminate tearing of the laminae, the sorting efficienoy of the mill will be generally found to be reduced.
Typical values for the resistance to delamination as a function of immersion time in the above test are shown graphically in E'IG 6~ The furnish in single wall corruyate having a basis weight of (590) gjm2 adhered with a starch base adhesive. "Control" conditions are considered to be where the solvent is water at 20 C. Curve 1 shows the variation of the resistance to delamination as a function of time under control conditions. At zero time, the resistance to delamun~tion considerably exceeds the strength of the individual laminae comprising the corrugate, and indiscrimlnate ~101 - 15 - B9602 P/5 C~
, tearing of the lamunae takes place, with relatively little separation of the paper qualities, "Easy dela~ination" is consider~ to occur when the resistance drops to an arbitrary ; ~Jalue of 60 grc~ms in the above described test procedure. Under this con~ition the strength of the adhesive bond will be normally less than the tear strength of the components. Additionally, the conditioned corrugate w;ll normally be subject to a force of at least this magnitude in m~ll 10. Under control conditions of treatment, easy delamination occ~rs after some 50 seconds of i~mersion (Point A)~
The moisture content of the conditioned corrugate is shown in FIG.7. Under control conditions it may be seen that the moisture content increas~s ~derately rapidly over the time period at c~bout which easy delamination is reached (Curve 1, Point A'). Althcugh not shown in the acco~panying data, it will be appreciatel that the wet strength of the illdividual laminae decreases hoth as the water content thereof increases and also as a function of time.
Under çontrol conditions it is foNnd that the wet strength of the laminae may approach zero, as eviden~ed by the disintegration of the laminae, after about 5 minltes immersion. There is then a differential between the time required for "easy delamination" and that at which disintegration and re-pulping of the corrugate laminae occurs. It will be appreciated that where prepulping of the material occurs, no separation of the qualities thereof is feasible by the instant ~ethod.
In practise this differential may be increased by removLng the corrugate frcm the treatment bath prior to the time at which easy delamination occurs. Solvent entrained with the corrugate will continue to attack the adhesive bond between the lam mae an~ r0duce the resistance to delamination. Part of the entrained solvent will tend to drain from the corrugate. A portion thereof will be imbibed into the corrugate to increase the moisture content thereof and thus to decrease the wet strength thereof. The quantity of solvent available for imbibition may generally be controlled so as to be less than that which will completely saturate the laminae and lead to their disintegration.
~le time differential may also be affected by the temper-ature of operation of the conditioning bath an~ the solvent employed.
In FIGS.6 and 7 values obtained where the temperature of operation is reduced to 10C are shown as Curve 2. Predictably, the time for easy delamination was increased, a value of 1.3 minutes being obtained (Point B)(FIG.7). Surprisingly, the moisture content of the corrugate at the time for easy separation (Eoint B')(FIG.6) was significantly less than that which obtains for the control, pointing to an increased time differential. It may also be re~arked that it 1~ advantageous to reduce the amount of solvent passing into mill 10, whether this be in free form or absorbed by the paper furnish.
rnhe control conditions were further varied by using as solvent water containing 0.004% by volume of a non-ionic surfactant (Triton X-100, trade~ark for a poly alkoxylated alkyl phenol),whilst maintaining the temperature of the bath at 20C. The values obtained are shown in FIGS. 6 and ~ in Curve 3. r~he time for easy separation was reduced, (P~int C~ in compariso~ to the control.
Whilst the rate of moisture pick up of the corrugate essentially duplicated that foun~ for the control, the moistur~ content of the :;corruyate at easy separation time (Point C'~ was significantly lower than that for the control, again pointing to an increased t~me differential.
It will be appreciated from the above that the moisture ~ 5 content of the preconditioned furnish can be somewhat varie~. It ~is generally found that the lower limit of moisture content of - pretreated koard for easy delamunation is about 45 percent by weight. The upper value for the moisture content of pretreated corrugate whe~ sorting corrugate in a commercial operation is generally about 75 percent by weight, it being generally preferred that the moisture conbent be in the range of about 55 percent to about 65 p~rcent by weight.
SORTING oF PRECONDITICNED FURNISH:
In a series of trials summarized in TAELE l, furnish consisting of single wall corruyate, samples of which were pre-viously found suitable in accordance with the aforedescribed test were reduced in size as n~ted in the TAELE and conditioned by steeping in water for a su.itable time, generally in the range of about 3 to 5 minutes at 18C an~ then drained for about 5 minutes.
The moisture content of the so conditioned furnish was measured and the materia]. fed into the chute 40 of mill lO operating under the conditions indicated. Visual observation showed that the furnish was generally delaminated up~n contact with radial propeller 46 and that it was well distributed about the circumference of impeller 16 upon entry to the space enclosed by ~creen 26 It shculd T~e understood that whilst it is believed that propeller 46 is conducive to an improved efficie~y of operation of mill lO, its : .
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presence is not n~ndatory and it may be dis~ensed with.
The ~11 10 was programmed by suitable choice of such parameters as screen mesh size, Impeller speed relative to the -; screen and clearance between the i~peller and screen to subject the conditioned furnish to an intensive scrubbing action. In multi ccmponent paper ~xtures such as are normally found in corrugate material, material programming will desirably progressively reduce the wea]cer components in size whereby they may pass through the mesh of screen 26 and be collected. Such programming will desirably not result in any appreciable size reduction in the last comp~nent, which will preferably be discharged from the en~ opening of the screen 26. By this means the energy consumption of mill 10 may be greatly reduced particularly where the last component comprises a significant pvrtion of the furnish in comF~l-ison to an arrangement whereby all canponents are r~duced in size to pass through the relatively small mesh openings normally provided on screen 26. It will be appreciated that the mesh of the screen of the last sectian or sections of the mill can be increased to such size that the last camponent would pass through without necessitating size reduction in this portion of the mill, and that such arrange-ment w~uld be entirely equivalent to that illustrated in FIGS. 1 an~ 2 herein.
The separation of the two components normally comprising corrugate, ie the linerboard and medium~ is found to be highly specific under ~cdel conditions and go~d yields of the tw~ components in high purity may be collected. The yield of linerbcard recovered - 19 - ~9~0~ P/5 C~
will depend considerably upon the desired purity of the recovered ~; material, which w;ll ~1 turn be so~ewhat dependent upon the end use for the recovered product. In the following reported trials t~he yield of linerboard is express~d at 90%, and g5~ purity, such as w~uld be attainable for exa~ple blending in optimum proportions recovered fractions Fl, F2, F3 and F4 collected at outlet hoppers 60, 62, 64 and 66 respectively.
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.
TABLE 1 SUMMARY OF OPERATING P~SULT.S
Furnish * a a ~ b Moisture Content, wt% 59 55 59 69 Feed rate kg/hr 600 600 600 600 Impeller speed rFm400 400 400 400 Impeller -screen clearance (~min.) cms 3 3 3 3 Fraction **
wt% 20 18 25 18 % liner in fraction 0 0 33 38 wt% 13 12 24 28 % liner in fraction 8 6 49 51
including corrugate, and if the ~JaSte to be recycled -- i.e. the "furnish" -- is ccmprised of mixed papers, it is ~urther known that such economic advantages may be enhanc~d, often to a considerable extent, by sorting the various papers com~rising the furnish according to their respective qualitative categories insofar and to the e~tent it is feasible and possible to do so prelimunary to the actual recycling thereof.
This expedient avoids or minimizes admixture of various paper grades in any one recycling operation which would usually relegate the recovere~ produst to a relatively inferior and, hence, cheaper re-use. Conversely, pre-sorting of the paper makes it possible for the better grades to be sep~ra-ted and recycled separately from the lesser grades and, hence, thereafter ` used in superior and resultantly m~re valuable applications.
In U.S Patent 4,124,168 is~sued Nove~ber 7, 1978 and co~nonly assigned herewith there ls described appaAratus and rnethod for sorting mixtures of papers of different grades. I'he method comprises exposing the dry paper components contemForaneously to a milling operation wherei~ the components are churned whilst avoiding cutting so as to selectively fragment the weaker c~nponents which are retrieve~ by passage through an enclosing screen. It will be apF~rent that slAch metho~ is unsuited for the - separation of corrugate, per se, as the physical nature thereof preclL~es the weaker component, ie the medium, from ~xposure to ~ 25 the selective frasmenting forces.
'; Various methods have been heretofore proposed for , ~ 3 ~ ~9602 P/5CI~
recovering corrugate. Such methods usucally comprise an initial step of breaking the adhesive bond between the liner~oard a~d the medium; subsequent steps to sort and separately recover the liner board an~ medium depo~ largely upon the nature of the initial step. In a first propo5al) small pieces of corrugated bcard are thoroughly mixed with a large excess of water, beaten under high energy conditions to form an all fibre slurry from which fibre qualitiès are reported to be separately recovered by centrifuging. - In a still further - 10 metho~ small pieces of corrugate are treated with limited quantities, in the range of about 20% to about 50% by welght, based on the weight of paper furnish, of a debonding liquid comprising a debonding agent dissolved in a suitable liquid vehicle therefor so as to separate the laminae in an essentially dry state. It appears that it may be necessary to pretreat the furnish thermally prior to contacting with the debonding liquidO
It is possible that corrugate furnish treated in this matter would be separable in the apparatus of aforementioned patent ~,124,168 and in accordance with the method described therein.
In my copending application Serial No. 343,875 filed January 17, 1980 and titled "Method and Apparatus for Preconditioning Laminated Paper for Recycling", c~nm~nly assigned herewith there is di æ losed a method generally inte~nediate the above extre~es whereby corrugate is contacted by a suitable solvent, generally water,to which may be added a ~nall quantity of wetting agent. Contacting is suitably carried out in a bath . . .
.
.
with paddles which sl~ merge the corrugate and propel it through the bath to provide a suitable residence time wnereby the water pick up is generally such that the m.oisture content of the corrugate emerging from the bath is usuallv at least a~out 50%
by weight. '~he adhesive bond between the liner and medi~n is llified and weakened by s~ch treatment wh~reby it is relatively easy to delaminate the corrugate; it is not believed that the delamination and sorting thereof to selectively recover canponent paper qualities 'nas been heretofore realized on a connercial basis.
It is a primary object of my invention -to provide a methcd for the separation and recovery of paper qualities from laminated papers.
It is a further object of my invention to provide a comnercially viable method for the separation and recovery of paper qualities from laminated papers.
It is a still further object of my invention to provide a methcd in accordance with the foregoing for the separation and recovery of linerboard fractions of gocd purity ar~ yield fran corrugate.
It is yet another object of my invention to pxovide appara-tus consonant with the achievesnent of the foregoing objects.
In accordance with one aspect of my invention, an apparatus for separating and recovering muxed papers comprises a mill including a screen and an impeller embraced thereby to chlrn and axially advance the papers in the mill and procure their selective fragmentation and the discharge of paper fragments through the screen, and unclogging ~eans for dislodging paper fragments trapped in the mesh of the screen during the milling ~GlOi~
- 5 ~ B9602 P/5 CA
operation.
In accordance with a` presently preferred aspect of the invention, the screen is tubular and rotates about its longitudinal axis, so as to bring portions of the screen to the proximity of the unclogging means, In accordance with anot~er presently preferred aspect of of the invention, the unclogging means is formed by a wiper dis~osed in close prcximity to the screen and rotating relative thereto. It is still further preferred that the unclogying means extend substantially the full length of the screen, and m generally parallel proximity thereto. Means may optionally be provided for varying the proximity of the unclogging means to the screen. The wiper, which may be in the form of a bnlsh, the bristles (which may be of any convenient material) of which may then be brought into contact with the screen so as to wipe the screen and rernove okdurately clinging material there-from, or be slightly spaced the~efrom so as to remove paper clinging to the .screen by mechanical contact with the paper or by entraining the paper in air currents generated by the rotating brush, and for this purpose the bnlsh may be constructed so as to generate desirable air currents.
In accordance with yet another preferred aspect of the invention the mill includes a hopper for feeding paper values into the screen enclosure, and a distributor is provided to intercept papers delivered to the nu`ll and generally break up clumps and distribute the paper around the impeller adjacent the screen inlet.
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- 6 ~ Bg602 P/S C~
It is presently preferred that the dis-tributor com2rises a radial propellor which acts to create an axial air flow through the mill, and entrain and distribute the paper feed in the air current. It is also presently preferred that the impeller comprise radial fins spaced thereakout an~ inclined in generally spiroid form w.ith respect to the longitudinal axis of the ~npeller 50 as to advance the papers through the ~ill, as earlier spoken of, and also to generate and supplement the axial air current generated ; by the distributor.
In accordance with another broad aspect of my invention, a method is provided for delaminating and recovering separately different paper qualities comprising different plies of a laminated ' ~ paper product. The metl~d ccnprises ap~lying a solvent to the laminated paper product to Frecondition it for delamination, of feeding the preconditioned laminated paper into a ~ill in which the paper is churned between an ~mpeller and an enclosing screen to procure the delaminatiQn and progressive fragmentation of the respect.ive plies whilst subjecting the screen to unclogging treatment to dislodge paper fragrnents trapped or otherwise retained thereon. In accordance with a further broad aspect of my invention, a method is provided wherein the churning is effected in a relatively clear and unobstructed churning zone between the im?eller and successive portions of the screen successively and cyclically presented in ~his zone, the successive screen portions being subjected to the - 7 - B9602 P/5 C~
unclogging treatment before its presentation in the zone, -rn accordance with the foregoing the unclogging treatment may ccmprise a simple mechanical action as by wiping, wherein the screen itself is wiped, as w~uld ~e indicated where clogging of the screen is particularly troublesome. Unclogging treatment may be less vigorous where indicated and comprise wiping of paper fragments which project through the screen and are trapp2d ; on the mesh thereof. Whilst the wiping may be carried out by the mechanical contact, it may also include the use of fluid currents, particularly air currents, which may be generated by a rotating wiper.
The method is unexpectedly advantageous particularly as applie~ to corrugate in that exposure of the corrugate to aqueous solvents for the purFose of mollifying and dissolving the adhesive bond between the-lamlnae has the further effect of decreasing the strength of the weaker component, ie the medium, to a proportionately ; greater extent than that of the stronger component, t~e lLnerboard.
In part this is due to the different nature of the ~ibres comprisincJ
the two c~alities of paper. It will be appreciated however that the linerboard component of corrugate i5 generally treated with size, and that such treatment reduces the rate at which water is imbibed by the liner. The medium is not usually treated in this manner, ancl the rate of water imbibition is greater t~an that of the linerkoard. In ccmparison to the method of aforementioned U.S. Patent 4,124,168, for sorting relatively dry mixtures of paper qualities, the forces for procuring the fragmentation of ~61~
~ ~ ~ B9602 P/5 CA
the weaker paper qualities may be s~what reduced herein due to their mechanically weakened state. It is observed in a properly progra~mel m;ll that the fragmenting forces of reduced strength have relatively little capacity to fragment the stronger linerboard component, and the power utilization of the instant method is appreciably lower per unit output. It is further observed that there is a more efficient transfer of energy between the rotor of the mill wherein the fragmentation is to be produced and the wet furnish therein than is normally achieved when using dry furnish, due to the increased density of the wet furnish, again leading to decreased p~wer require~ents.
It should be understood that whilst in the specification I speak generally of recovering separately paper qualities from laminated paper products, the apparatus and method of this invention will not necessarily be applicable to all laminated paper products as are presently known and as may be known in the future. The suitability of the method and app~ratus may be gauged by a simple test to be subsequently revealed herein.
My invention will be further explained in relation to ~0 the following description of a preferred embodiment thereof. Such description is for illustrative purposes only and should not be taken as keing limitative of the broad aspects of my invention.
IN THE DRAWINGS:
FIG. 1 - shows a ~11 constructed in accordance with the invention in perspective viewj partially broken away to reveal interior detail;
, _ 9 - ~9602 P/5 CA
FIG. 2 - shows the mill of FIG. 1 m side elevation partially in section;
FIG. 3 - is a view on line 33 of FIG. 2;
FIG. 4 ~ shows an impeller fin in plan view;
FIG. 5 - is a view on 5-5 of FIG. 4, and FIGS. 6 and 7 - relate to testing and preconditioning of furnish for the mill.
Referring now particularly to FIGS. 1 to 3, a paper sorting mill is represented therein generally by the numera1 10 and comprises a supporting framework 12 and a generally i~permeable housing 14. An im~eller 16 is mounted for rotation with shaft 18 journalled in bearings 20 located at opposed ends of the housing. Shaft 18 is driven through pulleys 22 by motor 24 to rotate in a first direction, here shown as clockwise, as viewed from the left hand end in FIGS. 1 and 2.
Impeller 16 is embraced by a screen 26 of stout wire which serves to retain the paper furnish within mill 10 whereby it is acted upon to delaminate and fragment the furnish selectively. The mesh openings of screen 26 are dimensioned to permlt sift~lg of paper frag~ents through the screen for collection.
Screen 26 is secured to c~nd supported by runners 28 at each e~d thereof which are rotatable on trunnions 30 secured to framework 12. Means (not shown) are provided to rotate screen 26 slowly and preferably in the contrary sense to the rotation of i~elIer 16.
Screen 26 is strengthened by securing axially aligned straps 31 to the oNtside thereof extending between op~osed runners 28. Further straps, ~hich are not here seen surroNnd screen 26 for strengthening ` Furposes.
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. , , ~ 10 - B9602 P/5 CA
Intermediate runners and trunnians ~ay also be provided for the pur~ose of additionally supporting screen 26, Impeller 16 includes a drlml 32 supported from shaft 18, and a plurality of f~ns 35 comprising blades 33 secur~d to the surface of the drum through the intermediary of mounting plates 34 The under surface of mounting plates 34 is axially grooved along the length thereof at 36 whereby mounting plates form saddles which sit securely on the arcuate surface of drum 32 when aligned with the axis thereof. The rno~nting plates 34 are secured to drwm 32 by bolts passing through openings 37 to form a plurality of axially aligned rows 38. Fin blades 33 are attached to saddle mounting plates 34 by welding at 39 to inter-sect the axis of the saddle mounting plate at the desired spiroid angle, generally in the range of about 15 to about 30, with 22 ~eing preferred for sorting wet papers, The adjacent ends of fin-blades 33 in a row 38 are in overlapping relationship.
Diagonally adjacent fin blades 33 are generally in spiroidal relationship. It will be appreciated that in accordance with this arrangement the fin blades 33 are planar and generally rectangular, as are r~cunting plates 34, thereby sumplifying the construction. ~lso it is relatively simple rNatter to replace the fins 35 so as to change the spiroid angle as may be desirable in accordance with a particular program for sorting a specific furnish. Of course, I do not preclude the use of arcuately shaped fins 35 or other alternati~e arrangements, particularly where other ~ans are used to advance the furnish in mill 10~
Mill 10 includes an inlet chute 40 having a throat 42 ~ B9602 P/5 C~
connecting the chute to the space enclosed by screen 26. Within chute 40 there locates an eiyht bladed radial propeller 44 secured to shaft 18 and driven therewith. The blades 46 of propeller 44 are pitched in the same direction as fins 35, each blade abutting to a fin, although the angle of pitch of the blades are preferably greater than that of the fins, generally a value in the range of about 30 to 45 having been found to be sultable. In operation,to be further described herein, substantial quantities of air are propelled through mill 10 by propeller 44 and also fins 35 acting in conjunction therewith. me ingress of air is desirably solely through inlet chute 40 via throat 42, and the egress of ~;r is desirably solely through air outlet opening 48 located at the axial end of mill 10 remote frcm chute 40. Cther points of likely ingress and egress are grossly sealed wi-th suitable flanges and covers as generally illustrated.
Impeller 16 is embraced by screen 26, the fins 35 of the impeller being suitably spaced from the screen so as to - procure a scrubbing action on paper furnish entrained between the fins and the screen and the selective fragmentation of the furnish thereby. The interior Æ face of screen 26 is generally devoid of elements that w wld coact closely with fins 35 to cut the feedstock as such cutting action is inimical with selective fragmentation. Ctherwise expressed, there is provided a relatively clear and unobstructed churning and scrubbing zone between the impeller and screen. The fragments of paper formed within m~ll 10 are removed from the action of impeller 16 by siev~ng through the mesh of cree 26 for colleotio . It is .
' found that when the screen 26 and impeller 16 are coaxially moun-ted, paper fragments are expelled about the whole periphery of screen 26. It is des~rable to limit the passage of paper fragments through screen 26 in at least one area thereof where there is positioned a screen unclogging means to be described, so as not to interfere unduly ~ith the unclogging-means. For ; this purpose I locate impeller eccentrically with respect to screen 26, preferably as shGwn by locating the axis of the im~eller shaft 18 beneath the axis of screen 26. The clearance between fins 35 is thus at a maximu~ at superior portlo~s of the screen, and the quantity of paper fragments passing through the screen in the zone is correspondin~ly at a mumLmum, hence it is here that I prefer to locate the unclogging means. Since the screen 26 rotates about its axis to move cyclically between the churning zones and unclogging means, successive portions of the screen are subjected to unclogging treatment before being re-presen-ted to the churning and scrubbing ~ and sieving zone.
; Impenmeable housing 14 includes a first end wall 50, locat~d generally in the plane of the inlet Openlng of screen 26, and a second end wall 52 located adjacent the end of the impeller adjacent air outlet opening 48 so as to generally surround the screen; In the instant embodiment a plurality of transverse partition walls 54, 56 and 58 through which screen 26 passes are shown axially spaced along mill 10, with partition walls 58 locating generally in the plane of the ou~let opening of screen 26, so as to divide mill 10 mto a number of co~ cb~ents.
-- 13 ~ ~9602 P/5 CA
The ]c~er portion of each cc~partment forms an ou-tlet hopper, respectively numbered 60, 62, 64 and 66. A rotary outlet feed 67 is located in the base of each hoEr~er so as to generally seal the outlet in conjunction with the pa~er fragments normally contained in the hoppers.
An unclogging means is provided for cleaning screen 26 and here c~nprises a brush 68 extending substantially the full length of screen 26. Brush 68 has its axis generally parallel to the axis of screen 26, and is mounted to be rotatable by motor 70 so as to move relative to the surface of screen 26.
An arcuate slot 72 centred on the drive shaft of motor 70 is cut in end wall 50, a similar slot (not seen) being cut in partition wall 58 to permit adjustment of brush 68 radially with respect to screen 26 by any convenient mechanism, typically a screw mechanism. Brush 68 locates adjacent the outer surface of - screen 26 an upper quadrant of mill 10, a position in the - range of about 30 - 60 from the vertical axial plane of screen 26 being preferred. A second unclogging means is further shcwn here comprising a compressed air conduit 74 generally coextensive with screen 26 having a plurality of jet openings 76 therein disposed to be directed towards the screen, this second unclogging means also being located adjacent screen 26 in an upper quadrant of mill 10.
The general arrangement of a specific embo~lme~t of the -~ 25 apparatus having been described, the operation thereof will be discussed.
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TESTING AND PRECONDITIONING OF FIJ~NISH
San~le strips 150 n~ by 15 ~ are cut frcm the furnish, where this is corrugated the major dimension being perpendicular to the flute channels. The strips are immersed in a suitable solvent to mollify, dissolve or otherwise weaken the adhesive ~ond between the laminae and withdrawn at time intervals and the resistance to delamination measured on an INSTR~N tester within 1.5 minutes of recovery frcm the solvent.
The resistance to delamination of corrugate is taken as the average force reguired to rupture the bond between crests of the n~dium and the lin~rboard. The furnish is generally considered to be amenable to efficient sorting in a mill such as mill 10 when the delamination occurs substantially at the interface of the laminae with a resistance measured in the test of about 60 grms. Where the delamination is accompanied by indiscriminate tearing of the laminae, the sorting efficienoy of the mill will be generally found to be reduced.
Typical values for the resistance to delamination as a function of immersion time in the above test are shown graphically in E'IG 6~ The furnish in single wall corruyate having a basis weight of (590) gjm2 adhered with a starch base adhesive. "Control" conditions are considered to be where the solvent is water at 20 C. Curve 1 shows the variation of the resistance to delamination as a function of time under control conditions. At zero time, the resistance to delamun~tion considerably exceeds the strength of the individual laminae comprising the corrugate, and indiscrimlnate ~101 - 15 - B9602 P/5 C~
, tearing of the lamunae takes place, with relatively little separation of the paper qualities, "Easy dela~ination" is consider~ to occur when the resistance drops to an arbitrary ; ~Jalue of 60 grc~ms in the above described test procedure. Under this con~ition the strength of the adhesive bond will be normally less than the tear strength of the components. Additionally, the conditioned corrugate w;ll normally be subject to a force of at least this magnitude in m~ll 10. Under control conditions of treatment, easy delamination occ~rs after some 50 seconds of i~mersion (Point A)~
The moisture content of the conditioned corrugate is shown in FIG.7. Under control conditions it may be seen that the moisture content increas~s ~derately rapidly over the time period at c~bout which easy delamination is reached (Curve 1, Point A'). Althcugh not shown in the acco~panying data, it will be appreciatel that the wet strength of the illdividual laminae decreases hoth as the water content thereof increases and also as a function of time.
Under çontrol conditions it is foNnd that the wet strength of the laminae may approach zero, as eviden~ed by the disintegration of the laminae, after about 5 minltes immersion. There is then a differential between the time required for "easy delamination" and that at which disintegration and re-pulping of the corrugate laminae occurs. It will be appreciated that where prepulping of the material occurs, no separation of the qualities thereof is feasible by the instant ~ethod.
In practise this differential may be increased by removLng the corrugate frcm the treatment bath prior to the time at which easy delamination occurs. Solvent entrained with the corrugate will continue to attack the adhesive bond between the lam mae an~ r0duce the resistance to delamination. Part of the entrained solvent will tend to drain from the corrugate. A portion thereof will be imbibed into the corrugate to increase the moisture content thereof and thus to decrease the wet strength thereof. The quantity of solvent available for imbibition may generally be controlled so as to be less than that which will completely saturate the laminae and lead to their disintegration.
~le time differential may also be affected by the temper-ature of operation of the conditioning bath an~ the solvent employed.
In FIGS.6 and 7 values obtained where the temperature of operation is reduced to 10C are shown as Curve 2. Predictably, the time for easy delamination was increased, a value of 1.3 minutes being obtained (Point B)(FIG.7). Surprisingly, the moisture content of the corrugate at the time for easy separation (Eoint B')(FIG.6) was significantly less than that which obtains for the control, pointing to an increased time differential. It may also be re~arked that it 1~ advantageous to reduce the amount of solvent passing into mill 10, whether this be in free form or absorbed by the paper furnish.
rnhe control conditions were further varied by using as solvent water containing 0.004% by volume of a non-ionic surfactant (Triton X-100, trade~ark for a poly alkoxylated alkyl phenol),whilst maintaining the temperature of the bath at 20C. The values obtained are shown in FIGS. 6 and ~ in Curve 3. r~he time for easy separation was reduced, (P~int C~ in compariso~ to the control.
Whilst the rate of moisture pick up of the corrugate essentially duplicated that foun~ for the control, the moistur~ content of the :;corruyate at easy separation time (Point C'~ was significantly lower than that for the control, again pointing to an increased t~me differential.
It will be appreciated from the above that the moisture ~ 5 content of the preconditioned furnish can be somewhat varie~. It ~is generally found that the lower limit of moisture content of - pretreated koard for easy delamunation is about 45 percent by weight. The upper value for the moisture content of pretreated corrugate whe~ sorting corrugate in a commercial operation is generally about 75 percent by weight, it being generally preferred that the moisture conbent be in the range of about 55 percent to about 65 p~rcent by weight.
SORTING oF PRECONDITICNED FURNISH:
In a series of trials summarized in TAELE l, furnish consisting of single wall corruyate, samples of which were pre-viously found suitable in accordance with the aforedescribed test were reduced in size as n~ted in the TAELE and conditioned by steeping in water for a su.itable time, generally in the range of about 3 to 5 minutes at 18C an~ then drained for about 5 minutes.
The moisture content of the so conditioned furnish was measured and the materia]. fed into the chute 40 of mill lO operating under the conditions indicated. Visual observation showed that the furnish was generally delaminated up~n contact with radial propeller 46 and that it was well distributed about the circumference of impeller 16 upon entry to the space enclosed by ~creen 26 It shculd T~e understood that whilst it is believed that propeller 46 is conducive to an improved efficie~y of operation of mill lO, its : .
- 18 - ~50~ P/5 CA
presence is not n~ndatory and it may be dis~ensed with.
The ~11 10 was programmed by suitable choice of such parameters as screen mesh size, Impeller speed relative to the -; screen and clearance between the i~peller and screen to subject the conditioned furnish to an intensive scrubbing action. In multi ccmponent paper ~xtures such as are normally found in corrugate material, material programming will desirably progressively reduce the wea]cer components in size whereby they may pass through the mesh of screen 26 and be collected. Such programming will desirably not result in any appreciable size reduction in the last comp~nent, which will preferably be discharged from the en~ opening of the screen 26. By this means the energy consumption of mill 10 may be greatly reduced particularly where the last component comprises a significant pvrtion of the furnish in comF~l-ison to an arrangement whereby all canponents are r~duced in size to pass through the relatively small mesh openings normally provided on screen 26. It will be appreciated that the mesh of the screen of the last sectian or sections of the mill can be increased to such size that the last camponent would pass through without necessitating size reduction in this portion of the mill, and that such arrange-ment w~uld be entirely equivalent to that illustrated in FIGS. 1 an~ 2 herein.
The separation of the two components normally comprising corrugate, ie the linerboard and medium~ is found to be highly specific under ~cdel conditions and go~d yields of the tw~ components in high purity may be collected. The yield of linerbcard recovered - 19 - ~9~0~ P/5 C~
will depend considerably upon the desired purity of the recovered ~; material, which w;ll ~1 turn be so~ewhat dependent upon the end use for the recovered product. In the following reported trials t~he yield of linerboard is express~d at 90%, and g5~ purity, such as w~uld be attainable for exa~ple blending in optimum proportions recovered fractions Fl, F2, F3 and F4 collected at outlet hoppers 60, 62, 64 and 66 respectively.
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- 20 - B9602 P/5 C~
.
TABLE 1 SUMMARY OF OPERATING P~SULT.S
Furnish * a a ~ b Moisture Content, wt% 59 55 59 69 Feed rate kg/hr 600 600 600 600 Impeller speed rFm400 400 400 400 Impeller -screen clearance (~min.) cms 3 3 3 3 Fraction **
wt% 20 18 25 18 % liner in fraction 0 0 33 38 wt% 13 12 24 28 % liner in fraction 8 6 49 51
3 5 3 8 18 % line~ in fraction 83 30 80 77 wt~ 62 67 43 36 % liner in fraction 100 100 98 97 Yield of linerb3ard 95% purity 100 99 7] 55 90% purity 100 100 76 71 Notes 2 2 * ~a) single wall, ~asis wt 590 g/m ; surface area ca 600 cm ;
mIn~mum dimension 20 cm (b) single wall, basis wt 590 g/m ; shredded to random size ** weight and percentages on dry material .; .
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Whilst in the re~orted trials four fractions are collected, and mill lO is constructed to acccmplish this end by the provision of intermediate partition walls 52, 54 and 56, the number of fractions that are desirably collected will vary according to the furnish and en~ use of the recovered material.
Under model r~onditions, shown in Table 1 as Runs l and 2, Fraction 4 accounts for in excess of 90% of the recovered liner-board and has a purity of 100%. It will be ap~arent that in this instance just two fractions could be collected with little loss in yield, and that the intermediate walls could ke omitted.
In Runs 3 and 4 where the furnish ccmprised linerboard shredded in a hammermdll to rando~ sizes, the relatively low yield of recovered Iinerboard is due mainly to the passage of fragments of linerboard produced in the shredding process thro~lgh screen 26, together with the fragments of medium produced in mill lO in the early fractions. It is to be remarked that the linerboard I
; contained in these fractions is completely delaniulated from the medil~n. The yield may be increased by reducirlg the mesh size of screen 26, at least in the first skages of the sorting. ~wever a preferred method of increasing the yield is to subject the ~ rly fractions to a further sorting operation in a ~ill lO
wherein the mesh size of screen 26 is suitably reduced. About 95+ % by weight of the individual pieces of liner~oard collected in Fraction 4 of Runs 1 and 2 were unchanged in size from furnish used in these Runs, indicating further the very high specificity of the ractionating process.
The peripheral speed of the various car~onents in the reported RLns was not found to be critical, and since the vement of the parts is relative the speeds will to sQme extent be interrelated.
Generally, and considering a mill lO wh~rein the diameters of screen 26, impeller 16 and rotary brush 68 are respectively 96 cm, 76 cm, - and 25 cm, screen 26 will rotate at some 2 to 10 rpm, and brush 68 at about 500 to 1000 rpm, and impeller about 200 to 700 rpn. It is emphasized that these ranges are illustrative and will be inter-dependent with other variables such as furnish, feed rate, residence lO time and hold-up, and clearance between the screen and impeller. In comparison to the sorting of relatively dry papers as in aforementioned U.S. Patent 4,124,168, the program for sorting the preferred furnish herein with its relatively high moisture content is less severe, due to the more efficient energy transfer from the impell~r herein to the furnish, and due also the weakened bonding between the fibers occasioned by exposure to moisture. A preEerred speed of rotation of impeller 16 dimensioned as above, in conjunction with preconditioned furnish, is generally not greater than about 400 rpm, c~bove which the yields of liner tend to be reduced and the power consumption increased.
20 me furnish is advanced rapidly under these program conditions by setting the fins 35 at a relatively large spiroid angle oc in the range of about 15 to 30, with 22 being preferred.
It will also be recalled that propeller 44 and fins 35 act to propel a significant air current throuyh mill lO which also serves to advance the furnish within the mill. Still other means are generally known in the art for advancing the furnish, which means may supplement or supplant those specifically used herein.
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'' ', In general, with corrugate furnish spoken of, residence times of up to about one minute are preferred.
When operating mill 10 under the conditions generally reported for Runs 1 and 2, screen 26 may be maintained m a 5 clean condition by the use of rotating brush 68 which is positioned so that the bristles thereof rotate in close proximity to the screen without physically wiping same. Visual - examination of the screen unclogging process under these conditions indicates paper fragments to lo~p around the wire mesh of screen 26, with one or both ends of the loop projecting outwardly frcm the screen. In some instances physical contact between the papex fragments and bristles of brush 68 is made, in others air currents entrained by the brush act to reorient the fragments and detach them from screen 26. Brush 68 is preferably constructed to induce air currents by spirally inclining the rcws of bristles~ Screen unclogging with air jets frcm jet openings 76 is also effective undex these conditions. In the absence o;f any unclogging means, screen 26 beccmes clogged at a generally exponential rate in the course of operating mill 10.
When operating mill 10 under conditions generally reported for Runs 3 and 4, using random size shredded corrugate board, visual examination of the screen in the absen oe of effective unclogging means reveals there to be a build up of fine matPxial ~hich adheres tenaciously to the inside surface of screen 26 and which acts to retain larger size paper fragments ~a~Ll - 2~ - ~96~2 P/5 C~
on the screen. When rotary brush 68 is used as an unclogg mg means it is positioned so as to mechanically contact and scrub the wire mesh of the screen. miS action may also ~e desirably supplemented by the use of air jets 76.
S The foregoing description of an operative embodiment of the invention being the best form of the invention presently knc~n to me, it is by no means inconceivable that me~ls or procedures other than those specifically enumerated may be resorted to and preferred for carrving out the inventive concepts described without departing from the substance of the invention as defined in the following claims.
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:
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mIn~mum dimension 20 cm (b) single wall, basis wt 590 g/m ; shredded to random size ** weight and percentages on dry material .; .
_ 21 - Bg602 P/5 CA
Whilst in the re~orted trials four fractions are collected, and mill lO is constructed to acccmplish this end by the provision of intermediate partition walls 52, 54 and 56, the number of fractions that are desirably collected will vary according to the furnish and en~ use of the recovered material.
Under model r~onditions, shown in Table 1 as Runs l and 2, Fraction 4 accounts for in excess of 90% of the recovered liner-board and has a purity of 100%. It will be ap~arent that in this instance just two fractions could be collected with little loss in yield, and that the intermediate walls could ke omitted.
In Runs 3 and 4 where the furnish ccmprised linerboard shredded in a hammermdll to rando~ sizes, the relatively low yield of recovered Iinerboard is due mainly to the passage of fragments of linerboard produced in the shredding process thro~lgh screen 26, together with the fragments of medium produced in mill lO in the early fractions. It is to be remarked that the linerboard I
; contained in these fractions is completely delaniulated from the medil~n. The yield may be increased by reducirlg the mesh size of screen 26, at least in the first skages of the sorting. ~wever a preferred method of increasing the yield is to subject the ~ rly fractions to a further sorting operation in a ~ill lO
wherein the mesh size of screen 26 is suitably reduced. About 95+ % by weight of the individual pieces of liner~oard collected in Fraction 4 of Runs 1 and 2 were unchanged in size from furnish used in these Runs, indicating further the very high specificity of the ractionating process.
The peripheral speed of the various car~onents in the reported RLns was not found to be critical, and since the vement of the parts is relative the speeds will to sQme extent be interrelated.
Generally, and considering a mill lO wh~rein the diameters of screen 26, impeller 16 and rotary brush 68 are respectively 96 cm, 76 cm, - and 25 cm, screen 26 will rotate at some 2 to 10 rpm, and brush 68 at about 500 to 1000 rpm, and impeller about 200 to 700 rpn. It is emphasized that these ranges are illustrative and will be inter-dependent with other variables such as furnish, feed rate, residence lO time and hold-up, and clearance between the screen and impeller. In comparison to the sorting of relatively dry papers as in aforementioned U.S. Patent 4,124,168, the program for sorting the preferred furnish herein with its relatively high moisture content is less severe, due to the more efficient energy transfer from the impell~r herein to the furnish, and due also the weakened bonding between the fibers occasioned by exposure to moisture. A preEerred speed of rotation of impeller 16 dimensioned as above, in conjunction with preconditioned furnish, is generally not greater than about 400 rpm, c~bove which the yields of liner tend to be reduced and the power consumption increased.
20 me furnish is advanced rapidly under these program conditions by setting the fins 35 at a relatively large spiroid angle oc in the range of about 15 to 30, with 22 being preferred.
It will also be recalled that propeller 44 and fins 35 act to propel a significant air current throuyh mill lO which also serves to advance the furnish within the mill. Still other means are generally known in the art for advancing the furnish, which means may supplement or supplant those specifically used herein.
:' - 23 - B9602 P/5 C~
'' ', In general, with corrugate furnish spoken of, residence times of up to about one minute are preferred.
When operating mill 10 under the conditions generally reported for Runs 1 and 2, screen 26 may be maintained m a 5 clean condition by the use of rotating brush 68 which is positioned so that the bristles thereof rotate in close proximity to the screen without physically wiping same. Visual - examination of the screen unclogging process under these conditions indicates paper fragments to lo~p around the wire mesh of screen 26, with one or both ends of the loop projecting outwardly frcm the screen. In some instances physical contact between the papex fragments and bristles of brush 68 is made, in others air currents entrained by the brush act to reorient the fragments and detach them from screen 26. Brush 68 is preferably constructed to induce air currents by spirally inclining the rcws of bristles~ Screen unclogging with air jets frcm jet openings 76 is also effective undex these conditions. In the absence o;f any unclogging means, screen 26 beccmes clogged at a generally exponential rate in the course of operating mill 10.
When operating mill 10 under conditions generally reported for Runs 3 and 4, using random size shredded corrugate board, visual examination of the screen in the absen oe of effective unclogging means reveals there to be a build up of fine matPxial ~hich adheres tenaciously to the inside surface of screen 26 and which acts to retain larger size paper fragments ~a~Ll - 2~ - ~96~2 P/5 C~
on the screen. When rotary brush 68 is used as an unclogg mg means it is positioned so as to mechanically contact and scrub the wire mesh of the screen. miS action may also ~e desirably supplemented by the use of air jets 76.
S The foregoing description of an operative embodiment of the invention being the best form of the invention presently knc~n to me, it is by no means inconceivable that me~ls or procedures other than those specifically enumerated may be resorted to and preferred for carrving out the inventive concepts described without departing from the substance of the invention as defined in the following claims.
.
:
:' ' .
Claims (34)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus for separating mixed papers comprising: -a mill including a screen and an impeller embraced thereby for churning said papers against said screen procuring selective fragmentation of said papers and the discharge of the resulting paper fragments through the screen while said papers are being advanced from the input end of said mill towards its output end, and unclogging means for dislodging paper fragments trapped in the mesh of the screen during the milling thereof.
2. Apparatus for separating mixed papers as set forth in Claim 1 wherein said screen is tubular and rotates about said impeller.
3. Apparatus for separating mixed papers as set forth in Claim 1 or 2 wherein said unclogging means is disposed in close proximity to the screen and rotates relative thereto.
4. Apparatus for separating mixed papers as set forth in Claim 1 or 2 wherein said unclogging means comprises a wiper disposed in close proximity to the screen.
5. Apparatus for separating mixed papers as set forth in Claim 1 including an input chute for delivering said papers to the input end of said mill, and a distributor located in said input chute for feeding said papers into the space enclosed by said screen.
6. Apparatus for separating mixed papers as set forth in Claim 1 wherein said impeller is elongated and equipped with radical fins spaced circumferentially about the impeller and extending in rows lengthwise thereof; the fins in each row being aligned with each other axially of said impeller and somewhat inclined to its axis.
7. Apparatus for separating mixed papers as set forth in Claim 6 wherein said fins are inclined to said axis at an angle in the range of about 15° to about 30°.
8. Apparatus for separating mixed papers as set forth in Claim 6 or 7 wherein said fins comprise a plurality of segments each said segment including a mounting plate therefor having an axially aligned groove in the under surface thereof so as to form a saddle.
9. Apparatus for separating mixed papers as set forth in Claim 1 wherein said unclogging means comprises a wiper extending substantially the full length of the screen and in generally parallel proximity thereto; means being provided for varying the proximity of the wiper to the screen.
10. Apparatus for separating mixed papers as set forth in Claim 5 wherein said impeller is elongated and equipped with radical fins spaced circumferentially about the impeller and extending in rows lengthwise thereof; the distributor being constituted by a plurality of blades co-rotatable with the impeller and disposed radially fan-wise over its end at the input to the mill.
11. Apparatus for separating mixed papers as set forth in Claim 9 wherein said screen is tubular and rotates about said impeller and the wiper rotates relative to the screen.
12. Apparatus for separating mixed papers as set forth in Claim 9 wherein the proximity of the wiper to the screen is variable by said means between one position in which the wiper brushes the screen and another position in which it is spaced marginally therefrom.
13. Apparatus for separating mixed papers as set forth in Claim 10 wherein the respective fins are inclined to generate an air stream flowing from the input end towards the output end of the mill when the impeller is rotating.
14. Apparatus for separating mixed papers as set forth in Claim 10 wherein each said blade is aligned with an impeller fin at the input end of said mill.
15. Apparatus for separating mixed papers as set forth in Claim 11 wherein the wiper is constructed to generate a current of air when it is rotated rapidly.
16. Apparatus for separating mixed papers as set forth in Claim 15 wherein the wiper is a rotary brush with rows of bristles extending lengthwise thereof.
17. Apparatus for separating corrugate comprising:
a tubular screen having an inlet end and an outlet end;
an impeller embraced by said screen for churning delaminated corrugate contained within said screen to procure the selective fragmentation of the medium layer, said impeller including air propelling means for propelling air from said inlet end to said outlet end;
a generally m permeable housing generally surrounding said screen, at least one transverse partition wall located externally of said screen adjacent said outlet end separate collecting means located on each side of said transverse partition wall for collecting paper discharged from said screen on each side of said partition wall;
an air outlet opening in said impermeable housing located in the end thereof remote from the inlet end of said screen, and unclogging means for dislodging paper fragments trapped in the surface openings of said screen.
a tubular screen having an inlet end and an outlet end;
an impeller embraced by said screen for churning delaminated corrugate contained within said screen to procure the selective fragmentation of the medium layer, said impeller including air propelling means for propelling air from said inlet end to said outlet end;
a generally m permeable housing generally surrounding said screen, at least one transverse partition wall located externally of said screen adjacent said outlet end separate collecting means located on each side of said transverse partition wall for collecting paper discharged from said screen on each side of said partition wall;
an air outlet opening in said impermeable housing located in the end thereof remote from the inlet end of said screen, and unclogging means for dislodging paper fragments trapped in the surface openings of said screen.
18. Apparatus as defined in Claim 17 wherein said air propelling means include radial fins spaced circumferentially about said impeller and inclined to the axis thereof.
19. Apparatus as defined in Claim 17 wherein said air propelling means includes a radial propeller located adjacent the intlet end of said screen.
20. Apparatus as defined in Claim 19 wherein said radial propeller is contained within a input chut connected to the inlet end of said screen.
21. Apparatus as defined in Claim 17 wherein said unclogging means comprises a rotary brush.
22. Apparatus as defined in Claim 17 wherein said unclogging means includes air jets.
23. Apparatus as defined in Claim 17 wherein said unclogging means locates adjacent said screen in an upper quadrant thereof.
247 Apparatus as defined in Claim 23 wherein the axis of the impeller locates below that of said screen.
25. A method of delaminating and separating the respective plies of laminated papers separably bonded together comprising the steps of:
applying a solvent to the laminated paper to precondition it for delamination by attacking and weakening the adhesive bonding of the respective plies to each other;
feeding the laminated paper with its weakened adhesive bonding into a mill in which the paper is churned between an impeller and a screen procuring delamination of the paper and the selective fragmentation of a constituent ply thereof;
collecting fragments of said constituent ply discharged through said screen, and collecting other constituents of said laminated paper at the outlet end of said screen.
applying a solvent to the laminated paper to precondition it for delamination by attacking and weakening the adhesive bonding of the respective plies to each other;
feeding the laminated paper with its weakened adhesive bonding into a mill in which the paper is churned between an impeller and a screen procuring delamination of the paper and the selective fragmentation of a constituent ply thereof;
collecting fragments of said constituent ply discharged through said screen, and collecting other constituents of said laminated paper at the outlet end of said screen.
26. A method of delaminating and separating the respective plies of laminated paper as set forth in Claim 25 wherein the churning of the paper is effected in a clear and unobstructed churning zone between the impeller and successive portions of said screen successively and cyclically presented at the zone aforesaid; each said successive screen portion being subjected to unclogging treatment to dislodge paper fragments trapped in its mesh before its presentation at the said zone.
27. A method of delaminating and separating the respective plies of laminated paper as set forth in Claim 25 or 26 wherein the preconditioned laminated paper is distributed upon its entrance to the mill to entrain the paper in air currents generated in said mill.
28. A method of delaminating and separating the respective plies of laminated paper as set forth in Claim 25 or 26 wherein the unclogging treatment is effected mechanically by physically wiping the paper fragments from the screen.
29. A method of delaminating and separating the respective plies of laminated paper as set forth in Claim 25 or 26 wherein the unclogging treatment is carried out by a combination of air currents and by physically wiping the paper fragments to dislodge them from the screen.
30. A method of delaminating and separating the respective plies of laminated paper as set forth in Claim 25 or 26 wherein the unclogging treatment is carried out by air currents directed at said paper fragments to dislodge them.
31. A method of delaminating and separating the respective plies of laminated paper as set forth in Claim 25 or 26 wherein the laminated paper consists of corrugate with a corrugated medium sandwiched between spaced apart plies of linerboard.
32. A method as defined in Claim 25 or 26 wherein said laminated paper is corrugate and the preconditioning step comprises applying an aqueous solvent whereby the moisture content of said corrugate is in the range of about 45 percent by weight to about 75 percent by weight.
33. A method as defined in Claim 25 or 26 wherein said laminate is corrugate and the solvent consists essentially of water, and wherein the moisture content of said corrugate when preconditioned is in the range of about 45 percent by weight to about 75 percent by weight.
34. A method as defined in Claim 25 or 26 wherein said laminate is corrugate and the solvent consists essentially of water and a minor quantity of a surfactant, the moisture content of said corrugate when preconditioned being in the range of about 45 percent by weight to about 75 percent by weight.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000358277A CA1161011A (en) | 1980-08-14 | 1980-08-14 | Board sorter |
| SE8100794A SE8100794L (en) | 1980-08-14 | 1981-02-04 | APPARATUS FOR SORTING PAPER FIBER PRODUCTS |
| GB8103638A GB2082217B (en) | 1980-08-14 | 1981-02-05 | Board sorter |
| FR8104756A FR2488627B1 (en) | 1980-08-14 | 1981-03-10 | APPARATUS AND METHOD FOR SEPARATING DIFFERENT QUALITIES OF PAPER CONTAINED IN OLD MIXED PAPERS AND, IN PARTICULAR, IN CORRUGATED PAPERBOARDS |
| JP4025381A JPS5739290A (en) | 1980-08-14 | 1981-03-19 | Paperboad peeling method , paperboad sorting machine and corrugated layer separator |
| DE19813132072 DE3132072C2 (en) | 1980-08-14 | 1981-08-13 | Method and apparatus for separating the respective layers of laminated paper |
| FI812514A FI812514L (en) | 1980-08-14 | 1981-08-14 | SORTERINGSMASKIN FOER KARTONG |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000358277A CA1161011A (en) | 1980-08-14 | 1980-08-14 | Board sorter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1161011A true CA1161011A (en) | 1984-01-24 |
Family
ID=4117655
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000358277A Expired CA1161011A (en) | 1980-08-14 | 1980-08-14 | Board sorter |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5739290A (en) |
| CA (1) | CA1161011A (en) |
| DE (1) | DE3132072C2 (en) |
| FI (1) | FI812514L (en) |
| FR (1) | FR2488627B1 (en) |
| GB (1) | GB2082217B (en) |
| SE (1) | SE8100794L (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3238742A1 (en) * | 1982-10-20 | 1984-04-26 | Escher Wyss Gmbh, 7980 Ravensburg | Process for the sorting of fibre material, especially for paper making, and sorting apparatus for carrying out the process |
| JPS61201712A (en) * | 1985-03-02 | 1986-09-06 | Kobe Steel Ltd | Pretreatment of molten pig iron |
| DE3935151C2 (en) * | 1989-10-21 | 1998-09-17 | Voith Gmbh J M | Rotor for a sorter for the recovery of fibers from paper or cellulose |
| DE4120685A1 (en) * | 1991-06-22 | 1992-12-24 | Hoechst Ag | LAMINATE MATERIAL WITH LATENT INNER DELAMINATION POTENTIAL |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB209648A (en) * | 1923-04-03 | 1924-01-17 | American Reduction Co | Means for recovering paper stock |
| GB1134611A (en) * | 1967-01-28 | 1968-11-27 | Australian Paper Manufacturers | Process and apparatus for cleaning and disintegrating fibrous materials |
| CH612707A5 (en) * | 1974-11-07 | 1979-08-15 | Ahlstroem Oy | Process for recovering fibres from fibre material, for example waste paper, and equipment for carrying out the process |
| SE406607B (en) * | 1975-11-14 | 1979-02-19 | Ahlstroem Oy | PROCEDURE AND DEVICE FOR TREATMENT OF RECOVERY PAPER |
| CA1078351A (en) * | 1976-12-29 | 1980-05-27 | Reed Ltd. | Paper sorting method and apparatus |
| US4224168A (en) * | 1978-11-20 | 1980-09-23 | Teafilter International A/Ps | Holder for filter bags |
| CA1127356A (en) * | 1980-01-17 | 1982-07-13 | Milos Stradal | Method and apparatus for preconditioning laminated paper for recycling |
-
1980
- 1980-08-14 CA CA000358277A patent/CA1161011A/en not_active Expired
-
1981
- 1981-02-04 SE SE8100794A patent/SE8100794L/en not_active Application Discontinuation
- 1981-02-05 GB GB8103638A patent/GB2082217B/en not_active Expired
- 1981-03-10 FR FR8104756A patent/FR2488627B1/en not_active Expired
- 1981-03-19 JP JP4025381A patent/JPS5739290A/en active Pending
- 1981-08-13 DE DE19813132072 patent/DE3132072C2/en not_active Expired
- 1981-08-14 FI FI812514A patent/FI812514L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5739290A (en) | 1982-03-04 |
| GB2082217A (en) | 1982-03-03 |
| DE3132072A1 (en) | 1982-04-22 |
| GB2082217B (en) | 1985-06-26 |
| FR2488627B1 (en) | 1986-12-05 |
| SE8100794L (en) | 1982-02-15 |
| FI812514L (en) | 1982-02-15 |
| DE3132072C2 (en) | 1987-02-05 |
| FR2488627A1 (en) | 1982-02-19 |
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