Abstract: For the purpose of separating coarse particles from a liquid such as water, e.g. in the cellulose industry, laundries etc., a vertical container is used in which a nozzle receives liquid from a pump and sprays the liquid in the form of a conical liquid jet up against the underside of a screening cloth. Above this cloth there is an outlet for the liquid, coarse particles impinging against the cloth and falling back to the bottom of the container. In accordance with the invention the total flow from the pump and jet is led off via the screening cloth and outlet above said cloth, the liquid level in the container being disposed between the nozzle and the screening cloth so that the liquid jet is sprayed through a layer of the liquid in the container before reaching the screening cloth.

Abstract: Method of removing slimes from slime-containing slurries in which the slurry is force fed at an acute angle onto a downwardly directed screen surface of a welded profile wire screen having fine screen openings at a pressure which for the slime content and impact angle of the slurry on the screening surface will project water and suspended slimes from the slurry through and beyond the screen a distance sufficient to cause gravity discharge of the slime suspension free of contact with the back of the screen below the impact area.

Abstract: A rotating sorter is provided for the removal of minuscule pollutants from fiber material suspensions by means of a symmetrical fixed filter basket disposed in a fixed spiral-shaped housing and in whose interior a generally vertical axle rotates sorter vanes in close proximity to the filter basket. Fiber material suspension to be sorted is delivered to a generally ring-shaped sorting space formed between the filter basket and housing. The direction of flow of fiber material suspension delivered to the filter basket occurs substantially tangentially thereto and generally perpendicular to the rotating axle, and quality material is sorted into the interior of the filter basket.

Abstract: Method and apparatus in screening a fiber suspension in a pressure screen (10) with an inlet (1) for the fiber suspension and outlets (2, 3) for accept and reject, respectively, a conduit (12, 13) being respectively connected to said outlets, the reject conduit (13) opening to the atmosphere at its end facing away from the reject outlet and being at least partially at a higher level than both inlet (1) and reject outlet (3), the flow through said conduit (13) being measured, the difference between the measured value and a criterion value being determined, and the flow through the reject conduit (13) being changed in response to a function of the difference of the change of the flow through the accept conduit (12) by means of a valve (7) in said accept conduit (12).

Abstract: A centrifugal pulp screen device including a perforate wall cylindrical screen, an outer enclosing housing, a centrally located stock supply conduit and a distributor for the stock including an annular distribution slice opening having a fixed lower lip and movable upper lip with the slice discharging against fixed angular vanes which direct the stock in a spiralling centrifugal flow along the inner surface of the screen with the volume of flow controlled by adjustment of the slice opening and the velocity controlled by a variable delivery supply pump and the velocity affecting the spiralling centrifugal action by impact of the stock against the vanes. A corresponding method for screening the stock is also disclosed.

Abstract: An apparatus for screening fibrous stock. The apparatus includes a preliminary screen, a rotor, and a cylindrical secondary screen. The stock first passes through the preliminary screen into the rotor and secondary screen. The preliminary filtered stock then passes through the secondary screen. Any stock not passing through the preliminary or secondary screens is discharged from the apparatus.

Abstract: A device for cleaning and recovering paper pulp includes a tank divided into inner and outer chambers by a fixed cylindrical sieve. The inner chamber also contains a rotating drum with blades that draw acceptable pulp from the outer chamber through the sieve to the inner chamber for discharge and moves rejected material through a helical path in the outer chamber toward another discharge point. The end of the helical path is blocked to form a dead space where the rejected material is concentrated and then periodically discharged.

Abstract: A method of separating fine coal particles from refuse particles comprising the step of:(a) providing a coal filter cake(b) forming a slurry of fine coal particles, refuse particles in a liquid mixture comprising water and organic liquid,(c) contacting said coal filter cake with said slurry,whereby a major portion of said water and a major portion of said refuse pass through said filter cake and a major portion of said organic liquid and a major portion of said fine coal particles pass across the top of said filter cake.

Abstract: A screening cylinder for use in screening apparatus for paper making stock includes a reinforcing skeleton structure comprising multiple bars extending generally axially of the inside of the cylinder which are welded to relatively heavy reinforcing hoops located at both ends of the cylinder and at a plurality of uniformly spaced locations along the length of the cylinder. Between each adjacent pair of these hoops is a plurality of circular rings of metal rod material arranged in closely spaced relation with each other and with the hoops to define a corresponding plurality of circumferentially extending screening slots.

Abstract: To fractionate fiber stock there is used a sieve device which can be constructed in the manner of a secondary stock pulper or fiberizer, yet contains a sieve having a hole size in a range of about 0.8 to 2.4 millimeters diameter. The fiberizer contains a rotor driven by a drive motor and equipped with arms movable around the sieve. At the side of the sieve confronting the rotor there is located a closed long fiber chamber with which merges the infeed line for a cleaned fiber stock suspension which is obtained from waste paper. At the same time a long fiber line leads out of this long fiber chamber into a long fiber vat or container. Behind the sieve there is located a short fiber chamber from which leads a short fiber line to a short fiber vat or container. In at least one of the lines there is arranged a throttle element which is actuated as a function of a signal received from a power measuring device.

Abstract: A screen apparatus for processing stock flowing into a papermaking headbox which includes a cylindrical housing, a tubular screen mounted longitudinally within the housing, and inlet means for introducing a stock suspension into the housing for flow through the screen. Outlet means are provided for receiving the suspension passing through the tubular screen for delivery to the headbox. The improvement of the present invention provides a helical slot in the housing which discharges stock passing through the screen into the outlet means. Foil means mounted for rotation coaxially with the cylinder are provided which create a pressure pulsation to cause a dispersal of the fibers and aid in the screening operation.

Abstract: Apparatus for screening a suspension of liquid, paper making fibers and undesirable rejects to remove a substantial portion of the rejects therefrom comprise a cylindrical screening member provided with circumferentially extending screening slots in the range of from greater than 0.008 inch to approximately 0.030 inch in width, and bars projecting from the inlet face of the screen and cooperating with rotating foils for creating a field of high intensity, fine scale turbulence adjacent the inlet face of the screen. The paper making fibers and other particles of elongated thin shapes can pass through the screening slots, but relatively chunky reject particles, which would pass through the larger openings of conventional paper making screens, are rejected without fractionation of the paper making stock or appreciable variation in the consistencies of the feed, accepts and reject flows.

Abstract: Baffles are added to the blade members of the rotor of an apparatus for screening fibrous stock to cause the flow of stock within the screening zone along the length of the blades to angle away from the blades rather than parallel with the blades. Passageways are added to allow untreated stock to be added at points deep within the screening zone to maintain a proper water to fiber ratio throughout the screening zone.

Abstract: The disclosure concerns a rotary screening machine for moving pulp suspension through a screening slot and for separating impurities from the pulp suspension. An annular rotatable drum is surrounded by an annular porous screen basket that is spaced away to define a screening slot. Pulp suspension is delivered to one axial end of the slot and is discharged from the other axial end of the slot. Generally wedged shaped vanes, widening in the axial direction between the leading and trailing ends of the vane, are provided around the drum. The wedge defining surfaces may also be inclined with respect to a respective plane perpendicular to the axis. The space between the wedge surfaces is an open volume. A wall in that space is oriented to help create appropriate vacuum and eddy conditions behind the vane. The drum may have different zones, with the lower zone being provided with vanes and the upper zone being generally smooth. Other types of vanes or projections may be provided in the intermediate zone.

Abstract: A seperator, for example, for use in paper production, of the kind having a rotationally symmetrical strainer through which the suspension flows, enclosed in a housing which has an inlet for the suspension to be cleaned and outlets both for cleaned suspension and for impurities held back by the strainer, and having blades revolving in front of the strainer which are divided into part-blades along the axis of rotation, that is, by planes perpendicular to the axis of rotation, and are offset relative to each other in the circumferential direction is disclosed. Several rows of part-blades are arranged over the strainer basket, these part-blades being of such a length and staggered over the circumference in such a way that substantially at every height level, relative to the height of the strainer basket, part-blades from several rows pass by the strainer basket. A separator free of troublesome pressure pulsations is thereby provided.

Abstract: A device for fiber fractionation to analyze for coarse particles or chips in which fractionation takes place by washing a sample of the fiber material on a horizontally disposed slotted plate submerged in water, a central bundle-type nozzle which extends from above into the water above the slotted plate, the jets of which are directed downwardly, preferably angularly, against the slotted plate, and means for collecting the material passing through the slotted plate.

Abstract: A separator for separating coarse particles from cellulose pulp suspensions and the like comprises a first separation chamber provided with an inlet for incoming mixture, a first outlet for the light fraction, and an outlet for an intermediate fraction enriched in coarse particles. A second separation chamber is provided with a second inlet, a second outlet for a light return fraction, and an outlet for separated heavy fraction, the outlet for intermediate fraction being connected to the second inlet leading from a first zone in the first separation chamber. Said zone has a higher pressure than a second zone connected to the second outlet, the second zone being located in the first separation chamber or connected to the latter, the first and second separation chambers thus communicating to form a circuit.

Abstract: A pressurized screening device has an inlet arrangement by which a feed slurry is directed to a central portion of a screening chamber, a plurality of chevron-shaped rotor foils are mounted for rotation near the inner surface of a cylindrical screenplate to split the flow of the feed slurry into separate flow portions directed toward opposite ends of the screening chamber, and separate reject chambers are provided adjacent its opposite ends of its screening chamber. The chevron-shaped foil structure enables the screening device to operate as if it were two smaller screening devices and to remove efficiently both light and heavy impurities from the feed stock.

Abstract: Apparatus for screening pulp slurry in an annular screening zone in the space between a screen of circular cross-section and a closed surface drum carrying pulse creating means, the screen and drum being coaxially mounted for relative rotation about their common axis, is characterized by means for feeding the slurry providing at least one inlet to the space extending substantially the full axial length of the screening zone, and means for removing from the space rejects not passing through the screen having at least one rejects outlet from the space extending substantially the full axial length of the screening zone.

Abstract: A paper machine screening apparatus generally includes a centrifugal pump member mounted for rotation about the axis of a tubular screen plate. A delivery passageway extends concentrically about the pump impeller for receiving pumped stock flow and includes an annular axially extending passage formed between a ribbed hub surface of the pump and the screen. Flow through the screen is passed from the screening apparatus to headboxes. Downstream of the annular passage is an end cavity for receiving particles unable to pass through the screen holes which are washed into the end cavity by the axial flow through the annular passage. The ribbings on the hub surface serve to agitate the stock flow to raise pressure forces tending to force flow out through the screen holes.

Abstract: In a screen device for a paper material which includes a substantially cylindrical housing equipped therein with a raw paper material inlet at its one end and with a refined paper material outlet and an impurity outlet at the other end, a cylindrical screen member disposed in said housing so as to divide it into an exterior chamber communicating with said raw paper material inlet and with said impurity outlet, and an interior chamber communicating with said refined paper material outlet, and a screen surface-cleaning mechanism disposed in such a manner as to rotate with a small gap between it and the screen surface of said screen member; the improvement wherein the screen open portions of said screen member are shaped into continuous slant slits, the slant angle is brought into substantial conformity with the flowing direction of the paper material flowing on the screen surface and the end slits on the downstream side in the passing direction of the paper material through the screen are left open.

Abstract: A pressurized screening device has two pairs of concentric cylindrical screenplates, one pair mounted coaxially above the other in a common housing. Each pair of screenplates has a separate rotary impeller mechanism, the impellers being mirror images of each other. The pair of screenplates share a common central feed chamber, common accepts chamber, and a common drive for the two rotary impellers. Each pair of screenplates is provided with a separate rejects collection chamber, one located at the base of the housing and the other located near the top of the housing. This arrangement permits both high capacity operation as well as efficient removal of heavy and light impurities from a feed stream.

Abstract: Pressure sorting method and apparatus in which the velocity of the rejected suspension component along the screen surface in a substantially direct path to a rejected suspension outlet has a vertical velocity component which is a multiple of the velocity of the accepted suspension through the screen openings by virtue of the cross-sectional area of the unsorted and rejects annular chamber at the inlet end being less than one third the sum of the clear cross-sections of the screen openings. The velocity ratio is maintained by decreasing the area of the annular chamber from the inlet to the rejects outlet. In a preferred embodiment, the accepts annular chamber increases towards the accepts outlet to compensate for the decrease in the unsorted and rejects annular chamber area.

Abstract: An installation for processing waste paper containing a stock pulper or slusher equipped with a rotor and two sieves or screens having different size holes or openings. By means of the sieve having the larger size openings there is conducted the obtained stock suspension through a primary line system which, for instance, leads to a papermaking machine. Cooperating with the sieve having the larger size openings or holes is an auxiliary circulation circuit containing a device for the removal of contaminants or rejects. There is preferably arranged at the auxiliary circulation circuit or system a separator for heavy contaminants or rejects, a pump, a secondary stock pulper or fiberizer and a sieve or filtering device.

Abstract: In screening apparatus for paper making fiber incorporating a cylindrical screen member provided with screening perforations which are either cylindrical or slotted in section, the perforations are characterized by greater flow area on the inlet side of the cylinder than on the accepts side of the cylinder. More specifically, each of the screening perforations includes a generally funnel-shaped portion on the inlet side of the cylinder which leads to a short parallel sided portion on the accepts side of the cylinder.

Abstract: A sieve chain having upper and lower ends is disposed in a housing and comprises a plurality of sieve sections and hinge means connecting adjacent ones of said sieve sections in series from one of said ends to the other. Each of said sieve sections has an inclination in the general direction from said upper to said lower end. A hinge connects one of said ends of said chain to said housing. An adjusting device is hingedly connected to the other end of said chain. The suspension flows over said sieve chain in the general direction from said upper to said lower end.

Abstract: A rotary pulp screening device is disclosed which is less sensitive to variation in pulp flow, pulp consistency and pressure than existing pulp screens. The device is of the vertical pressure type and includes a cylindrical housing having an upper inlet chamber and a lower screening chamber with a disc ring dividing the upper chamber from the lower chamber, an inlet aperture in the upper chamber, a cylindrical screen mounted within the lower chamber, a rotary impeller mounted for rotation about a central vertical axis within the screen, the impeller being approximately in the form of a paraboloid, means for rotating the impeller, impeller blades radiating from the impeller and extending to within a short distance of the screen over the length of the screen, at least two dilution systems for diverting dilution water into different areas of the screen and a pulp discharge outlet from the lower chamber outside the pulp screen.

Abstract: A plurality of parallel sieve bars are transversely spaced apart in a plane to form a sieve. Each sieve bar has a side face enclosing an angle with the plane and diverging therefrom in the same direction so that the side faces constitute a stepped surface on said one side of said sieve. In sieving apparatus, such a sieve is arranged with said sieve bars spaced apart in an inclined plane and all side faces are disposed on the upwardly facing side of the sieve so that the angles of inclination of the side faces decrease progressively in groups of bars or from bar to bar.

Abstract: A rotary screening apparatus is provided for separating impurities in suspensions such as paper pulp or other slurries. The apparatus has a pressurized housing with a cylindrical screenplate separating the housing into an outer annular accepts chamber and an inner feed chamber. An impeller with one or more blades is mounted inside the feed chamber and imparts a rotary motion to the slurry. A series of horizontal baffles attached to the impeller divide the feed chamber into at least three sections. Piping is provided to inject dilution liquid into at least the lower two sections at separately controllable rates to compensate for the dewatering which occurs in the inlet section. The ability to treat and control individually each successive section of the screening device enables essentially complete separation of desirable fibers from impurities.

Abstract: A screening apparatus for screening fibrous material in liquid suspension includes a housing having an inlet and accept fraction outlet and reject fraction outlet. The suspension is introduced under pressure via the inlet. A cylindrical screen is positioned centrally within the housing to define an involute reject passage within the housing and outboard of the screen with the rejected fraction passing under pressure from the reject passage outwardly of the housing via the rejected fraction outlet. The accepted fraction passes from the reject passage inwardly through the screen and is then passaged under pressure outwardly of the housing via the accepted fraction outlet. The suspension is under pressure in its travel through the apparatus and is pulsed en route by a plurality of elastically mounted diaphragms driven in compressing and decompressing strokes by means eccentrically mounted on a rotating mainshaft.

Abstract: A pressurized screen particularly adapted for screening paper making pulp includes a cylindrical screen plate mounted in a cylindrical casing and defining with it an annular chamber which receives unscreened pulp from which rejects are removed as the good pulp passes from the annular chamber through the screen plate. The axes of the screen plate and the casing are offset with respect to each other, forming an enlargement of the chamber which extends approximately from an inlet into the annular chamber to a rejects outlet which is diametrically opposite the inlet. A partition in the chamber extends parallel to the axes of the casing and screen plate from a position opposite the inlet to a position above the rejects outlet.

Abstract: An apparatus for sorting a fibrous suspension for removing both heavy weight and light weight particulate impurities is disclosed. An antechamber is positioned above a main chamber. Fibrous stock suspension is inletted tangentially to the antechamber and moves down to the main chamber. An annular rotor in the main chamber creates a vortex of the fibrous stock suspension, which drives the heavier particulate impurities to the side wall of the main chamber and moves the lighter weight impurities toward the center of the vortex. The heavier weight impurities fall to the bottom of the main chamber from which they are removed. The lighter weight impurities are removed by a drainage line extending toward the center of the antechamber. Above the rotor is a strainer and the rotor cooperates with the strainer to drive purified fluid suspension to an annular outlet chamber surrounding the bottom of the antechamber and from there into an outlet line.

Abstract: A glass bead separating apparatus and method are disclosed, for use with a slurry blast cabinet. The system is capable of continuous operation, so that glass beads which are broken and undersized can be separated out of the slurry along with debris from the blasting operation, on a continuous basis while blasting takes place, and the slurry can be continuously returned to the blasting cabinet in the purified condition. Used slurry is withdrawn from a hopper at the bottom of the blasting cabinet, pumped up to the top of the separator apparatus and delivered through a nozzle over an inclined screen sized to pass everything but reuseable, whole glass beads. The reuseable beads are collected in a bin, while the remainder passes down onto another, much finer screen which retains nearly everything but the liquid slurry medium, which is preferably water. The relatively clean water drops into a holding tank at the bottom of the separator apparatus, with an overflow weir provided to maintain a preselected water level.

Abstract: The disclosure concerns an apparatus for separating impurities from a fibrous suspension. The apparatus includes a tiltable housing having a screen basket supported coaxially therein. A rotor is supported inside the screen basket. The rotor has three zones. There is an upstream zone communicating with the fiber suspension inlet, and inlet in the upstream zone is into the interior of the rotor and then outward past sorting vanes formed at the exterior of the rotor in the first zone and inside of the basket. Downstream of the transport vanes is a second baffle zone defined by a closed drum having transport vanes on the outside thereof. The suspension and impurities are moved downstream by the transport vanes in the second zone. Downstream of the second zone is a third zone with further means for moving impurities downstream, comprising either a centrifugal impeller in the form of vanes or a helical ring.

Abstract: An apparatus for screening fibrous stock. A rotor is rotatably mounted within an open ended, cylindrical screen which is mounted in a hollow housing. Fibrous stock is introduced into the housing and rotation of the rotor causes the portion of the fibrous stock that will pass through the screen to do so. Any fibrous stock that passes through the screen is discharged from the housing. The rotor includes a cylindrical body member having a plurality of blade members attached thereto and spaced substantially evenly about the circumference of the body member and radiating outwardly therefrom. Each blade member has a leading edge and a trailing edge with the leading edge spaced farther from the body member than the trailing edge.

Abstract: A solid-liquid separation element which remarkably, improves the solid-liquid separation capacity of a solid-liquid separation device having the separation element therein is provided. In this separation element, guide members for accelerating the through-flow of the liquid are mounted on the back surface of a stationary inclined screen and, optionally, guide members for transporting solid materials are arranged on the surface of the screen so as to be substantially in parallel to each other and in a downward inclining direction from both edges of the screen. The solid-liquid separation apparatus having said separation element and a cleaning brush which is reciprocated in rubbing contact with the back surface of the screen is also provided. The range of the reciprocating motion of the brush is more than the width of the screen.

Abstract: A pressurized screening apparatus removes both bouyant contaminants and denser contaminants from a liquid suspension containing desirable fibers and contaminants. Both the undesirable bouyant contaminants and the undesirable denser contaminants are accumulated in the same section of the pressurized screening apparatus. If desired, the accumulating bouyant contaminants and denser contaminants may be intermittently removed from the pressurized screening apparatus.

Abstract: The stock slurry pulsing rotary foils in a cylindrical paper making machine screen comprise sets which are shorter than the screen and respectively extend from opposite ends of the screen and have their inner end portions alternating in circumferentially spaced but axially overlapping relation. Thereby, the frequency of the hydraulic pulses transmitted directly to the accepts outlet is increased, but the total amplitude of the foil pulses transmitted to the outlet pipe is reduced, and this is accomplished without significant change in horsepower for driving the foil means, as compared with an arrangement of half the total number of foils wherein each foil extends throughout the effective length of the screen.

Abstract: An apparatus for sorting fiber suspensions comprising a stationary cylindrical screen cage and a rotor having a cylindrical wall mounted concentrically relative to the screen cage to form an annular space, the unsorted fiber suspension entering the annular space at one end and flowing generally toward the other end of the annular space, the fiber suspension increasing in consistency as it flows toward the other end of the annular space, the rotor having openings and/or elevations to cause the dilution of at least a portion of the thickened stock in the annular space not passing through the screen with a portion of lower consistency fibrous suspension to allow it to flow more readily. In one embodiment the rotor is mounted within the screen cage and a portion of the unsorted fiber suspension is introduced to the interior of the rotor, passing outwardly through openings in the rotor along the length of the annular space to dilute the thickened, dewatered suspension within the annular space.

Abstract: A centrifugal screening apparatus for scalping or sizing bulk materials in which an auger assembly conveys the bulk materials from an intake chamber into a cylindrical screening sleeve mounted within an enclosed screening chamber and subjects the bulk materials to centrifugal force for impingment against the screening sleeve, with the fines passing through the screen for gravity discharge from the screening chamber and the tailings being conveyed to a separate tailings chamber for separate gravity discharge therefrom. The auger assembly within the screening sleeve is equipped with a cylindrical shell integral with the auger assembly and extending the effective length of the screening sleeve that defines along the length of same uniformly spaced apertures thereabout that are separated by imperforate walling.

Abstract: An apparatus for purifying paper pulp in the liquid state by screening. The apparatus comprising a cylindrical fixed screen disposed coaxially with a rotor within a housing. The rotor has longitudinal blades which, in section transverse to the rotor axis, have the general shape of an angle one side of the angle being substantially radial to the rotor and a second side inclined thereto. This apparatus is capable of both centripetal and centrifugal operation, and at concentrations of from 3 to 4%.

Abstract: A classifying apparatus for a suspension, especially for a pulp suspension, having a screen drum, means for feeding the suspension to one side of the screen drum, for removing thickened suspension from the same side of the screen drum and liquid from the opposite side of the screen drum, blades inclined in relation to their direction of rotation so that any one of the ends of the inclined blades is substantially on the same screen drum line parallel to the screen drum axis as the opposite end of some other blade and fitted to sweep at least one surface of the screen drum, and driving means for moving the blades in relation to the screen drum.

Abstract: A screening apparatus for fiber suspensions comprising a stationary cylindrical screen one side of which is in flow communication with the inlet for the fiber suspension and the other side, from which the accepted stock emerges, forming an annular space with a rotor comprising a cylindrical wall having elevations for producing positive and negative pressure thrusts serving to keep the screen clear and openings behind the projections through which some of the accepted stock passes to provide an alternative path to the outlet for the accepted stock.

Abstract: A method and a system for cleaning and classifying fibrous suspensions whereby the suspension, by screening, is divided into a first stream of accepted stock and a second stream of rejected stock. The latter is then screened once more and thereby divided into a third stream of accepted stock and a fourth stream of rejected stock. The third stream is added to the first stream, whereas only the fourth stream is subjected to a fibre flake break-up process followed by a further screening process resulting in a stock finally rejected and an accepted stock added to the fibrous suspension upstream of the means for carrying out the first screening.

Abstract: In screening apparatus for paper fiber stock of the type wherein a cylindrical perforate screen member defines screening and accepts chamber on the inner and outer sides thereof in a closed housing, the inlet chamber for stock to be screened is located below the screening chamber, and the reject chamber for accumulating reject material is located above the screening chamber. Provision is made for retaining high specific gravity materials within the inlet chamber and for trapping and removing them therefrom without ever reaching the screen chamber. In addition, provision is made for developing centrifugal force effective to concentrate low specific gravity materials, such as bits of plastic foam, in the central part of the reject chamber, and a discharge outlet from the reject chamber located generally centrally of its top wall assures elimination of such light reject materials.

Abstract: A method and apparatus for treating a suspension of liquid, paper making fibers and undesirable rejects to remove a substantial portion of the rejects from the suspension. A cylindrical screen is utilized which has narrow slots on the order of 0.001 to 0.008 inch in width disposed normally with respect to the screen axis, and bars projecting from the inlet face of the screen and cooperating with rotating foils for creating a field of high intensity, fine scale turbulence adjacent the inlet face of the screen. This permits the paper making fibers to pass through the narrow screen openings but causes very small reject particles, which would pass through the larger openings of conventional paper making screens, to be removed without fractionation of the paper making stock or appreciable variation in the consistencies of the feed, accepts and rejects.

Abstract: A fractionating apparatus for separating fine fibers from coarse fibers in water containing a certain amount of air. A spray nozzle is arranged in a vessel and directed towards a screening cloth incorporated as a part of the vessel walls and which, on its discharge side, is arranged for free runoff of the fine particles and the part of the liquid passing through the seal means to its discharge side, while coarse particles and the other part of the liquid is bounced off the inner side of the screening cloth and collected in the vessel to a predetermined liquid level maintained by allowing the liquid to depart through an outlet. A desired pressure difference is maintained across the sieve means. The vessel is closed with the exception of the places where the sieve means are situated and where the outlet is arranged.

Abstract: Method and apparatus for pulping and grading waste material in which the waste material is introduced into a cylindrical chamber having two end walls with a perforate screen in one of the end walls. An impeller in the chamber adjacent the perforate screen provides for pulping and pumping of the stock as well as provides rotational movement of the stock within the chamber. Lightweight rejects are continuously removed through an outlet centrally located in the end wall opposite the screen and heavy rejects are removed through an outlet in the cylindrical wall adjacent the end wall opposite the screen. The stock is introduced to the chamber through an annular inlet which surrounds and is coaxial with respect to the lightweight rejects outlet line.

Abstract: An apparatus for straining liquid fibrous suspensions to remove contaminants and foreign objects has a stationary screen basket located in a housing. Purging blades rotate in the interior of the screen basket in close proximity to the interior walls of the screen and create pressure pulses, causing trapped contaminants and foreign objects to migrate toward an outlet, whereas the purified suspension, including the useful fibers, passes through the screens.The average path traversed in the apparatus by contaminants and foreign objects is shortened due to the disposition of an intermediate chamber, at mid-height of the screen basket, through which contaminants may also be eliminated from the apparatus. The purging blades are appropriately extended to sweep the walls of this intermediate chamber. The shortened average path reduces the probability that contaminants will pass through the screen on their way to the outlet.

Abstract: Apparatus for the refinement of colloidal asbestos dispersions comprises a horizontally disposed cylindrical tube having a plurality of closely spaced holes around the periphery thereof, a helical screw disposed within the tube, and a flanged jacket concentric with and spaced outwardly from the tube. A slurry of unrefined dispersion is continuously fed into the tube to fill it. Refined slurry is drawn through the holes by a suction pump connected to the jacket while contaminants are retained in the tube and moved by the screw to the outlet end of the tube where they are compacted and removed as sludge through a spring loaded discharge door.