Abstract: A method of treating a pulp suspension in a screening plant of a pulp mill wherein reject impurities are separated from defibered pulp by screening and/or cleaning, the cleaned pulp is thickened to a consistency of from about 10 to about 20%, the impurities are further treated in the screening plant by screening and defibering the accept fiber material for further screening and thickening and further reject impurities are removed from the screening plant after various screening stages, the method including effecting one or both of the pulp screening and cleaning stages in a closed, pressurized space in the screening plant and preventing the access of air to the pulp treated by effecting the thickening stages in a pressurized state and at the initial pressure of one or both of the preceding screening and cleaning stages.

Abstract: A stock liquid is made to flow into a cell through a stock inlet at one end of the cell. The stock liquid is admixed with air bubbles from an air bubble generating device disposed at a lower portion of the cell and extending between the opposite end plates of the cell, thereby forming the stock liquid into a spiral flow. Ink particles are entrapped by the air bubbles to deink the stock liquid and the air bubbles remain as froth over the free surface of the stock liquid. The froth is made to flow down to the froth trough. The deinked stock liquid is discharged to the exterior of the cell through the stock outlet at the other end of the cell.

Abstract: The invention relates to a method for controlling pressurized screening devices in which fiber pulp is fed to the pressurized screening device and is divided into the accepted portion of the fiber pulp passing through perforations of a cylindrical screenplate and the rejected portion which is removed from the screenplate, the perforated screenplate being treated by a device movable relative thereto and rotatable around the center axis of the screenplate, the fiber pulp being fed parallel with the center axis of the screenplate to baffle blade assembly comprising at least two baffle blades and also being rotatable around the center axis, wherein the speed of rotation of the baffle blade assembly and/or the radial dimension of the baffle blades are adjustable to control the screening. The invention additionally relates to pressurized screening devices for implementing the method.

Abstract: An apparatus, for pressurized screening of a fiber/liquid suspension to separate the fibrous fraction into an accepts portion and a rejects portion, has a housing having an inlet with a heavy and large material trap, an accepts outlet, a rejects outlet, and a dilution liquid inlet. A hollow cylindrical screen having an open top and bottom communicates with the fibrous suspension inlet chamber and the rejects outlet chamber. Accepts fibers in the suspension pass through apertures in the screen to the accepts chamber and are discharged through the accepts outlet. Rejects discharge through the rejects chamber. A rotor having at least four regions, a closed top, and a bottom mounted drive mechanism is coaxially mounted within the screen. Hydrodynamic pulses are induced in the suspension in the screening region by a pattern of bumps and/or depressions impressed upon the rotor surface.

Abstract: The present invention provides an improved arrangement for removing thread-like impurities, such as wire rope, wire and the like, from a defiberizing drum or the like used in the defiberizing of waste paper. A ramped or inclined member, in the form of a bar or a lath, is disposed within a first or inlet portion of the drum and is secured to the drum casing wall at a predetermined distance from the partition wall that separates the first portion from a second portion of the drum. As the drum operatively rotates, a wire ball or mass forming within the first drum portion is elevated by the ramped member to a height sufficient to bring the mass into proximity with an opening defined in the partition wall, thereby directing the mass through the partition wall opening and into the second portion of the drum for further processing and/or discharge from the drum.

Abstract: A system and process for sizing wood chips to provide a flow of wood chips which are acceptable for feeding to a digester of a pulping system. A flow management screen station is provided which divides an incoming unacceptable flow into two fractional flows, neither of which is acceptable for feeding to the digester. One of the output flows from the flow management screen is concentrated in oversized and overthick chips compared to the incoming flow. The other output flow is concentrated in undersized chips and particles compared to the incoming flow. The output flows from the flow management screen are then fed to second and third screening stations which separate "overs" from the respective flows to provide acceptable flows to the digester.

Abstract: The invention relates to a method and a screening apparatus (1) for screening pulp. In the method, the maximum length of fibres and shives flowing through holes (4a) in a screen drum (4) is adjusted by moving blades (8) with a sharp front edge close to the surface of the screen drum (4) in such a manner that the sharp edge (8a) of the front face moving closest to the drum surface strikes shives or long fibers passing through the hole (4a) and pulls them back. The rate of travel of the blades (8) is so adjusted that the pulp flows in the hole (4a) only over a distance corresponding to the predetermined fiber length during the interval between the front edge of two successive blades (8). The screening apparatus (1) comprises blades (8) moving in parallel with the surface of the screen drum (4). The front edge of the blades defines in cross-section a sharp angle, the point of the angle defined by the front edge moving closest to the surface of the screen drum (4).

Abstract: Agglomerated ink-containing particles formed during the fiberization of wastepaper in a dry deinking process can be condensed and streamlined in shape to render them more readily separable from the balance of the fiberized wastepaper by slurrying the fiberized wastepaper with water at a temperature of about 130.degree. F. or greater with appropriate agitation.

Abstract: The invention relates to a method and a device for screening and treating pulp. In the invention, the pulp is screened in a screen into an accepted fraction and a rejected fraction, the rejected fraction being treated after the screening by removing water from it. In order to reduce the energy consumption of the refining process, the rejected pulp fraction is screened by means of a means (13) rotating rapidly in a reject space (12) of a screen (1) in such a manner that the rapidly rotating means (13) effects a radial flow of the fine-grained material contained in the rejected fraction outwards through a perforated wall (14) surrounding the rotating means (13) into a space (15, 15a) from where the fine-grained material is discharged.

Abstract: An apparatus is disclosed for removing ash from repulped wastepaper which contains ash together with cellulosic fibers. The apparatus includes a frame and a plurality of rolls which are rotatably secured to the frame, such that the axes of rotation of the rolls are spaced and parallel to each other. The plurality of rolls include an upstream roll and a downstream roll having a cylindrical outer surface. A porous belt is supported by and extends around the plurality of rolls to define an endless loop. The belt moves between the upstream and downstream rolls for defining a screening portion. A headbox is disposed within the endless loop, and adjacent to the screening portion for ejecting the repulped wastepaper through the screening portion. A drainage device is disposed on the opposite side of the screening portion relative to the headbox for receiving ash passing through the screening portion.

Abstract: In apparatus for thickening a suspension of pulp material which includes an endless foraminous belt wrapping two spaced horizontally supported rolls, a special doctor mechanism is provided for transferring thickened pulp from the bare surface of the second roll into a trough mounted in the space bounded by the two rolls and the upper and lower runs of the belt. More specifically, the doctor mechanism includes a rigid doctor blade mounted with its working edge in close but spaced relation with the bare surface of the roll to remove pulp therefrom without contact with the roll surface. Provision is also made for periodically oscillating the blade about a horizontal axis to move its working edge away from and back to its closely spaced working relation with the roll.

Abstract: A method for the screening of defibred pulp bleached in several steps. In the method, the pulp coming from an acidic bleaching step (2) is screened (3, 4, 5, 6) at the same time as it is treated with an alkali. In this way, no separate alkali stage is needed.

Abstract: To remove disturbing wax particles and for increasing the specific volume the short fiber fraction is subjected to a thermal treatment, especially by application of water vapor or steam, in a heater, such as a worm heater throughout a defined residence time and a defined temperature. With relatively low energy expenditure the distrubing wax particles are eliminated in such a manner that no wax spots or speckles can be discerned in the finished product. The specific volume of the short fiber fraction is appreciably increased while obtaining a predetermined strength.

Abstract: A waste paper de-inking system of this invention agitates and mixes waste paper dissolving slurry and treating gas by a multi-stage type vapor-liquid mixer before a floatator treating step, separates and finely pulverizes ink and sticky matters adhered to fiber in the waste paper dissolving slurry and sufficiently absorbs and contains the treating gas in the slurry before reaching the lower most stage to facilitate de-inking operation in later floatators. Further, the high tower multi-stage vapor-liquid mixer can be utilized also as a floatator to reduce a required floor area and required power consumption of the system.Further, high temperature exhaust gas containing SO.sub.2 produced in a factory is utilized as the treating gas to perform various operations, such as desulfurization, heat recovery, bleaching and also purification of a factory environment, thereby a more economical waste paper de-inking system is provided.

Abstract: The fibers of recycled paper are cleaned by agitating the slurry containing the fibers to maintain the fibers in suspension, and contacting the slurry with wash water to remove ink and other contaminants. The apparatus includes a passageway having screens forming opposite sides of the passageway. Agitators are within the passageway, and create enough turbulence to prevent fibers from settling or agglomerating. Channels adjacent to each screen carry wash water, and pump pressure creates a pressure differential across the screens to cause the wash water to contact the slurry and to be removed from the passageway.

Abstract: There has been provided a system and apparatus for recovering turpentine from a thermomechanical pulping process for making paper, which thermomechanical pulping process utilizes a plug screw conveyor for squeezing and feeding pulp chips. The thermomechanical pulping process is conventional. The liquid effluent from said plug screw conveyor contains an appreciable amount of turpentine. The liquid effluent is collected under superatmospheric pressure and flashed into vapor/liquid separator by releasing the pressure on the liquid. This vapor is condensed in a suitable condenser and the condensate collected in a decanter where the turpentine collects as a separate phase and the water also as a separate phase. Condensate from various vents in the conventional thermomechanical pulping process may be collected for more nearly compelete removal of turpentine and other oleoresinous components.

Abstract: A method and several embodiments of apparatus are disclosed for use in foam flotation separation. The method discloses performing the separation in a module operated at nonatmospheric pressure, and the apparatus disclosed are suitable for use as the module of the method. Both the method and the apparatus contemplate positive and negative pressure operation.

Abstract: Improved chemimechanical, particularly chemithermomechanical, pulp (CTMP), is produced by defibrating or refining wood chips to produce pulp, and then screening the pulp and separating out at least 30% by weight of the incoming fiber suspension as a first long-fiber fraction, and also separating out a first fine-fiber fraction, screening the first fine fiber fraction a second time, and separating out a second long-fiber fraction which is combined with the first long-fiber fraction to form a long-fiber fraction of improved properties, and a second fine-fiber fraction of improved properties.

Abstract: Resin is removed from mechanical pulps, such as TMP, CTMP, and the like, in a quick and simple manner. Mechanical pulp at a consistency of about 7-20 percent (preferably 8-15 percent) is subjected to high turbulence. The high turbulence may be effected by fluidizing the pulp, as in a centrifugal fluidizing pump, or otherwise by subjecting it to high turbulence as in a mixer, screen, or disc mill refiner. By subjecting the pulp to high turbulence treatment for a time period of about 0.2-10 seconds, resin removal is greatly enhanced, and in subsequent dewatering of the pulp a pressate is formed which has a higher concentration of resin in the pressate than in pressates produced by conventional processes. After dewatering the pulp is preferably diluted (again to about 7-20 percent consistency), and the turbulence and dewatering steps are repeated. Chemicals to improve deresination can be added to the pulp while it is subjected to high turbulence.

Abstract: Apparatus for treating of old printed papers includes a recycling conduit for the thickening waters of a long fiber fraction upstream of the fractionation apparatus to the pulping and pre-purification apparatus, and a reservoir for the recovery of thickening waters of a short fiber fraction and of thickening/washing waters of the long fiber fraction. This reservoir is fed with clean water for starting the installation and is connected with a second reservoir such that overflow from the first reservoir empties into the second reservoir.

Abstract: A sorting apparatus for sorting fiber suspensions heavily laden with rubbish and other contaminants, which sorter has two successive sorting units each having a ring-shaped strainer space, which are likewise successive, and an accepts space with a rotationally symmetric strainer between the accepts space and strainer space. The first sorting unit is pressurized above atmospheric pressure; diluting water is fed to the second unit strainer space; and a rotating plate is mounted between the first and second sorting units to control the flow between the strainer spaces.

Abstract: A method of delignification of cellulosic fiber material is described. The pulp containing said cellulosic fiber material is fed in a main line containing a main reactor in which the pulp is treated with oxygen. The pulp is screened at at lest one point in the main line, and the screen reject obtained is fed in a branch line containing at least one secondary reactor for separate treatment with oxygen. According to the invention the separate treatment with oxygen is carried out without previous refining, and the screen reject thus separately treated in said branch line is returned to the main line at a point upstream of said main reactor.

Abstract: In continuous pulping processes for cellulosic fiberous material pulp, a changeover from deciduous wood raw material to coniferous wood raw material without interruption of the production process, and with a minimum waste of pulp, is provided. The pulp mixture during changeover, having a consistency of about 8-15% is fed to a screen in which the pulp is separated into two pulp fractions depending upon fiber length. A fiber length analyzer is placed in the pulp stream between a treatment or storage vessel and the screen, and controls the rejects line from the screen to determine the amount of pulp passing out the screen rejects conduit. The screen may be directly in a production line from a continuous digester, refiner, or like device for producing the pulp, or it may be connected to a storage vessel to which pulp from a digester or the like has been fed.

Abstract: An apparatus and method for improving the quality of paper manufactured from recycle paper stock which comprises a hydrokinetic amplifier, a pulper, a dump chest, a cyclone separator, a pressure screen, a vibratory screen and a holding tank. Contaminants contained in the fibrous stock are dispersed and emulsified during the process to produce a better quality fiber stock. The hydrokinetic amplifier generates pressure at its exit while dispersing the contaminants in the fiber stock. The energy possessed in the stock can be utilized to feed the stock through additional treatment devices such as ultrasonic generators and a device for causing the stock to take a tortuous path as it is passed therethrough to further break down the contaminants.

Abstract: The apparatus has a main line having stages of cleaning batteries (S1-S5). The respective battery of each individual stage consists of cleaners such as hydroclones which produce three fractions. The medium fraction is conveyed from stage to stage. The heavy fraction of the first stage is cleaned in a first secondary circuit (N1) and the light fraction of all main line stages S1 to S5 is cleaned further in a second secondary circuit N2. The heavy fraction of the main line stages (S2 to S5) following the first stage (S1) is conveyed as accept to a paper machine reservoir, as is the light fraction of the first secondary circuit (N1). The heavy fraction of the second secondary circuit (N2) is conveyed to the inlet of the main line first stage (S1), whereas the light fraction of this second secondary circuit (N2) is cleaned further. The hydroclones of the two secondary circuits may be of the type which is capable of preparing three fractions.

Abstract: The present invention relates to a method of removing ink from secondary fiber by contacting a pulp of said secondary fiber with an aqueous medium in the presence of a polymeric material having a glass transition temperature in the range of from about 20.degree. C. to about 70.degree. C. and a substituted polyethylene oxide to agglomerate the ink into discrete masses and separating the agglomerated ink from the pulp-containing aqueous medium.

Abstract: Method and device for preparation and primary separation of paper pulp in which the initial disintegration is produced in a primary pulper 1 of known type, the contents of the pulper, after this separation is discharged directly and discontinuously into a large-sized vat where it is stirred by an agitator with longitudinal shaft equipped with spiral arms, and from there poured discontinuously into a separator.

Abstract: In a pulping apparatus including a pulper with a rotor near the bottom therein, the pulper has a sluice outlet at the bottom for acceptable pulp suspension. Above the rotor at a corner of the pulper is a second outlet for suspension and dirt. A conduit leads from the second outlet to a horizontally oriented withdrawal apparatus chamber having a suspension agitating rotor at the end of the chamber opposite the entrance for pulp thereinto. A tangential outlet from the withdrawal apparatus chamber lead to a rotary, perforated sorting drum which permits exit of acceptable suspension and which has a rejected suspension and dirt outlet. A valve in the inlet to the withdrawal apparatus chamber is periodically and cyclically opened to permit periodic replacement of the suspension in the withdrawal apparatus chamber, and the suspension which has been agitated in the withdrawal apparatus chamber then moves to the sorting drum.

Abstract: A method and apparatus for decomposing waste paper in a storage tank (tower) under the effect of chemicals with a high stock concentration (high-consistency stock method), including the rotation of the paper pulp together with dilution and a vigorous extensive disintegration of the waste paper or rags by a slushing rotor in the lowest part of the storage tank (tower).

Abstract: A method of processing baled secondary fibre furnish is provided. The method includes the steps of breaking the baled furnish, dry screening the furnish to remove abrasive contaminants, and then repulping the dry screened furnish.

Abstract: A method and apparatus for removing stringy contaminants from a pulp in a wastepaper recovery system having a pulping vat with an elongate helically shaped rod in the vat with means for causing a relative rotation between the stock and the helical rod so that long slender contaminants will be captured and climb the rod. In one form, multiple helices are employed and the rods may be driven in rotation, or the stock caused to rotate about the helix by other means.

Abstract: Method in a paper manufacturing process for improving the properties of the paper, in particular its retention. In the method, the fibre material is passed through a refining and screening system to the head-box arrangement of a paper machine, which comprises one or several head boxes, through which the stock suspension is fed onto a forming wire or into a forming gap (G) between a pair of forming wires (40,41). Two different components are formed out of basic stock which contains substantially all the fibres to be used for the paper to be manufactured. Of these components, one component contains mainly fibres longer than the average distribution of fibre length in the basic stock, while the other stock component contains mainly fibres shorter than average and fines as well, in addition to a possible additive component or components for the stock, if any. The stock component of longer fibres is fed, by means of a multi-channel head box, into direct contact with the forming wire or wires (40,41).

Abstract: A waste paper recycling process relates to the treatment of a mixture of waste paper containing non-cellulosic contraries and printing inks, in order to release the contraries from the fibers and further to separate them from the stock in order to produce re-usable pulp for the production of paper and board.The invention has to do with new and useful improvements in methods for first removing the non-ink contraries from the fibrous mass and second releasing and then removing the ink particles from the said fibrous mass.The invention is directed to the treatment of the fiber slurry produced during the ink separation stage, after the ink releasing stage has been applied. One aim of the process is to allow both the use of the fibers and the mineral fillers contained in that slurry, for pulp and board making, and the use the solids-free water contained in the same slurry as the washing liquid in the previous ink-separation treatment, thus closing the fibers and the water circuits.

Abstract: A process is provided for producing high yield bleached cellulose pulp, such as groundwood pulp, thermomechanical pulp, chemimechanical pulp and waste paper pulp, having a broad field of use, which comprises bleaching cellulose pulp, thinning the pulp to a low pulp consistency; mechanically working the pulp; and fractionating the cellulose pulp into a long-fiber fraction and a fine-fiber fraction, the freeness of the long-fiber fraction exceeding the freeness of the fine-fiber fraction by from about 150 to about 600 ml C.S.F. and the fine-fiber fraction constituting from about 35 to about 70% by weight of the bleached pulp.

Abstract: Sulfite pulp having increased tear, Scott bond, and stretch properties and above about 90% dirt reduction without bleaching. Methods for making such sulfite pulp by increasing the consistency of conventional sulfite pulp to above about 12 percent, shearing the increased consistency pulp under compressive forces to improve the tear and stretch properties of the pulp, refining the sheared pulp at pressures above atmospheric to remove dirt particles and achieve a desired freeness level, and removing fiber knots from the refined pulp.

Abstract: A screen and a coaxially radially spaced rotor provide a fluid passage for the fibrous material--liquid suspension. The rotor surface has the effect of pumping or assisting a flow of dilution liquid from the reject end towards the inlet end of the fluid passage, thereby partly or wholly offsetting the natural thickening of the suspension during screening.

Abstract: A method and apparatus provide for the bleaching of mechanical pulp in such a way that the brightness of the mechanical pulp can be increased up to about 7-10 points. Mechanical pulp directly from a secondary refiner is separated, as by first and second centrifugal separators (cyclones), into a fines fraction and a fiber fraction. The fines fraction is under about 200 mesh. The fiber fraction is mixed with hydrogen peroxide (H.sub.2 O.sub.2) and subjected to displacement bleaching, which uses a minimum about of bleaching chemical to obtain the maximum brightness. The fines fraction is mixed with hydrogen peroxide and subjected to non-displacement bleaching. The fines fraction is between about 10-20 percent of the total feed pulp stream. After bleaching, the fines and fiber streams can be recombined before passage to a paper products production machines.

Abstract: An apparatus for improving the quality of paper manufactured from a contaminated fibrous stock having therein recycled paper pulp and contaminants smaller than a predetermined size and with a specific gravity approximately that of the specific gravity of whitewater used in the production of recycled paper stock comprises a hydrokinetic amplifier having a mixing chamber connected to each of a steam inlet, a stock inlet, a chemical feed inlet, an overflow discharge and a venturi. The venturi is connected to an outlet of the hydrokinetic amplifier. The apparatus also includes a pulper, a dump chest, a cyclone separator, a pressure screen, a vibratory screen, a holding tank, a pump, and various auxiliary pumps, valves, piping and sources of steam and whitewater.

Abstract: Apparatus for thickening a suspension of pulp material employs a single pair of liquid-impervious rolls and a single loop of wire trained around both rolls which are spaced from each other in substantially the same horizontal plane. The pulp stock to be thickened is delivered into the wedge zone defined by the upper wire run approaching the top of one roll and the surface of that roll, so that the pulp is trapped between the wire and roll as it travels around the roll with the wire, and the rolls are driven at sufficient speed to develop centrifugal forces which cause liquid to be expressed through the wire from the pulp trapped against the roll.

Abstract: In deinking, the flotation of fiber suspensions is performed in a cylindrical tank 2 to which the fiber suspension is fed through a coupling means 36 as primary stream. The fiber suspension is already aerated and is withdrawn through a suction connection 33 below the coupling means 36 and fed after another aeration through a secondary connection 35 above the coupling means. The volume of the circulated secondary stream is greater than the volume of the primary stream. It is thereby assured that the fiber suspension is aerated at least twice and thus better cleaned.

Abstract: A process and a secondary pulper used in a system for waste paper conditioning wherein the secondary pulper has a tumbling space separated from an accepted stock space by a screen. The secondary pulper includes a central drain line through which a fraction of fiber suspension enriched with light dirt is removed at one end of the secondary pulper, and a circumferential line through which a fraction of the fiber suspension enriched with heavy dirt is removed from the secondary pulper. A pulp inlet sleeve surrounds the central drain line and receives fiber suspension enriched with heavy dirt from the circumferential drain line through a conduit from the circumferential drain line to the pulp inlet sleeve so that the fiber suspension enriched with heavy dirt enters the tumbling space adjacent the entrance to the central drain line.

Abstract: The invention relates to an apparatus for the separation of edge trimmings, in connection with a pulper. The upper portion of the jacket of the pulper (1) serves as a jacket of a first cyclone (5), a second cyclone (8) opposite in direction being provided within said cyclone (5). When the air flow enters the second cyclone and the direction thereof is reversed, it is essentially retarded, whereby also light paper particles fall into the stock contained in the pulper. The object is to provide an efficient device for the separation of edge trimmings, which device does not spread dust in the surroundings.

Abstract: Ink-bearing secondary fiber feedstocks are mechanically fiberized in a substantially dry state to produce substantially discrete fibers and ink-bearing fines, and the fibers are separated from the fines in a substantially dry state.

Abstract: In screening apparatus for paper making stock including a housing, a cylindrical perforated screen member separating the interior of the housing into a supply chamber and an accepts chamber on the inside and outside respectively of the screen member, an inlet port for supplying stock to one end of the supply chamber, an outlet port from the accepts chamber, a reject port from the supply chamber, and a rotor mounted for rotation within the screen member, the rotor is characterized by comprising a substantially circular disk which is of a thickness constituting a very minor fraction of the axial length of the screen member and has vanes mounted on its outer periphery which extend lengthwise of the screen member for rotation with the disk in the annular space between the periphery of the disk and the inner surface of the screen member.

Abstract: A twin hydrocyclone used for instance in cellulose and paper mills for purifying pulp suspension, the twin hydrocyclone consisting of two hydrocyclones mounted with their larger ends against each other and having one common infeed connector and one common purified fraction discharge connector. The hydrocyclones of prior art have the drawback of complex design and of division of the feed flow causing disturbances in the feed flow in view of the hydrocyclone's operation. The twin hydrocyclone, meant to solve these problems, is characterized in that the feed flow from the common infeed connector of the hydrocyclones is directed to each hydrocyclone as a separate feed flow by means of a helical member the helices of which constitute, in each hydrocyclone, feeding ducts confined by the walls of the hydrocyclones.

Abstract: An assembly for straining of pulp suspensions and the like comprises a strainer drum (1) mounted in a strainer house (2). One or a plurality of devices (5-9) are provided, in order to free impurity particles from fibers, preferably designed like an impact plate, in the strainer house (2) in the flow path, so that the particles in the stream partly are subject to an impact action, and so that the stream is subjected to a variation in velocity.

Abstract: A rotary pulp screening device of the vertical type is disclosed having a high screening efficiency and high capacity. The screen provides a streamline flow of pulpstock, and aims to supply a fairly constant flow of pulp through the screen from top to bottom, thus utilizing the full height of the screen. The screening device includes a cylindrical housing with a vertical cylindrical screen therein, a rotary impeller mounted for rotation within the screen, the impeller having a body whose top is substantially level with the disc ring and bottom is adjacent the lower end of the cylindrical screen, the body having a shape with circular axial cross section from the top to the bottom, whose diameter increases from the top to the bottom thus leaving a larger annular space at the top, and impeller blades radiating from at least a portion of the body of the impeller and extending to within a short distance from the screen for the height of the screen.

Abstract: A system for wastepaper processing which uses a newly developed wash filter of a simple design. The wash filter includes a generally round agitating space and an accepted stock space. The accepted stock space is separated from the agitating space by an essentially flat screen. An agitating wheel is positioned within the agitating space and in front of the flat screen. An entrance space for receipt of fibrous suspension and wash water is also included in the wash filter. The entrance space has a smaller diameter than the diameter of the agitating space. Flow of the suspension from either a primary pulper or a secondary pulper is received in the entrance space of the wash filter. A tailing removal line is in communication with and extends from the agitating space of the wash filter.

Abstract: An improved method for screening and fractionation. By using a housing interiorly divided by a screen plate into a primary and a secondary chamber with the secondary chamber further divided by a fluid impermeable wall, a process fluid stream containing particulate material has a second and a third process fluid stream diverted from it. The second stream is outputed from the housing while the third stream is recirculated to the first chamber. It is demonstrated that high screening or fractionation efficiency is obtained by this method.

Abstract: A method of deinking comprises: (a) mechanically fiberizing a secondary fiber source in a substantially dry state, preferably air dry, thereby producing a fibrous material consisting of substantially discrete fibers and ink-bearing fines: (b) depositing the fibrous material onto a moving screen or wire which retains fibers and allows fines to pass therethrough; and (c) lifting the fibrous material above the screen with upwardly directed forced air and redepositing the material onto the screen, whereby upon re-deposition of the material, additional fines pass through the screen.