Abstract: A screen for fibre pulp is provided with means for removal of light reject. The screening apparatus comprises a vertical cylindrical screen (2); and a rotor (3) which is concentrically disposed inside the screen and the substantially closed outer surface (9) of which together with the inner surface (10) of the screen defines a screening zone (11) for the pulp. A pipe (19) is provided inside the rotor (3) the upper end of the pipe being disposed adjacent to the inner surface (21) of the closed upper end (12) of the rotor (3).

Abstract: The sorting apparatus contains a screen forming at least part of a circular-cylindrical surface and a rotor having a rotor shaft which is coaxially located at the lengthwise axis defined by the circular-cylindrical surface. The rotor possesses clearing blades and propelling blades arranged to follow or trail the clearing blades as seen in the rotary direction of the rotor. The clearing blades each comprise a front-positioned clearing edge which moves along the screen and a run-up surface which is inclined relative to a radial direction defined by the rotor. The run-up surface moves the fiber stock in a direction towards the rotor shaft and provides an open through-passage in the central region of the rotor. The propelling blades extend from the rotor shaft towards the screen and terminate at a distance from the surface defined by the screen.

Abstract: An apparatus for treating a fibre suspension in a liquid to remove therefrom solid foreign particles. The apparatus has an inlet for receiving inflowing fibre suspension mixed with solid foreign particles; a first outlet for discharging part of the suspension liquid and said solid foreign particles; a screen positioned to define a filtering enclosure extending between said inlet and first outlet; a rotor disposed within said filtering enclosure for rotation therein to apply to the suspension fluidizing forces breaking up interlocked fibre flocs present therein and thereby fluidizing a part of said suspension to exit therefrom through said screen; and a second outlet communicating with the exterior of said screen to allow exit of fluidized suspension.

Abstract: A screening device for immersion in a vessel containing a pulp or slurry, said device comprising a screening chamber having at least one side wall defined by a screen and closed at the top and bottom said screen being located to be immersed in the pulp or slurry, a discharge pipe located within the screening chamber having an open lower end and positioned close to the bottom and an upper end opening into a discharge outlet external to said vessel said discharge outlet being located below the surface level of the pulp or slurry and above the level of the bottom of the chamber, the capacity of the discharge outlet being such as to maintain a flow rate through the screening chamber and discharge pipe to maintain the solids in the pulp or slurry passing through the screening device in suspension.

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 process, and apparatus for recovering cellulose fibers from contaminated paper-plastic mixtures by exposing the mix to controlled wetting to increase the weight of paper cellulose components relative to the weight of the plastic components; subjecting the wetted mixture to abrasive forces to fiberize the paper component and then separating the fiberized paper cellulose product from the plastics and other contaminants, to yield several classified products showing distinctly improved quality.

Abstract: A centrifugal screening device comprises a cylindrical screen surrounded by a cylindrical casing spaced radially from the screen. A central shaft inside the screen carries a plurality of blades which are inclined so that material fed into one end of the space between the shaft and screen is thrown toward the screen by centrifugal force and is also propelled axially of the screen to an exit at the other end. Fine material passing through the screen is collected in a funnel at the lower end. The screen is made up of semicylindrical sections each comprising a frame in which metal mesh is secured by strips of woven synthetic resin material.

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 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: 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: 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 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: 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 drum type screening machine has a centrifuging rotor within it. A perforated retaining element is carried by the shaft between a feed inlet and an entry region of the drum. The perforations of the retaining element are small enough to retain the foreign bodies which it is intended to retain but larger than the perforations of the screen. The retaining element has an access aperture, a closure element and means for holding the closure element movably in position to close the aperture. The retaining element can be a basket made up of a perforate plate with a perforate rearward flange. The closure element can be a half-moon segment, located by locating pins and rotatable on the shaft with respect to the remainder of the retaining element on clearing the locating means when pressed axially against the force of a bias spring. Use of the retaining element prolongs the screen life so much that tension adjustment become necessary. Provision is made for this to be done from outside of the machine.

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: Method and apparatus of concentrating solids from a suspension by feeding material in a liquid medium to a first zone that includes a vertically oriented foraminous filter basket supported by circular bands which are connected to an open frame basket supporting cage. Rotary impeller arms significantly spaced from the basket inclined from the vertical and located about midway of the lower half of the basket impart a circular laminar movement to the material. A vertical cylindrical tank surrounds the basket. Filtrate is collected in the annular region between the basket and tank. Discharge outlets with rate of discharge controls extend outwardly and downwardly from the bottom of the separator apparatus. Operation can be batch or continuous with level of filtrate in the tank being maintained on a par with the level of the feed in the basket.

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: 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: A method and mechanism including a housing having a screening chamber therein with a cylindrical screen and foils rotating past the surface of the screen with the housing having circumferentially spaced outlets which are at nonuniform circumferential locations, are different in number than the foils, and lead to a common manifold which will lead to a paper machine headbox. An air dome is at one end of the chamber.

Abstract: The pressurized screening apparatus for screening fibrous material in liquid suspensions includes a fixed cylindrical screen mounted within a housing to form an inner chamber. An axially extending annular channel receives the suspension. A dilution liquid is passed tangentially into the channel. The dilution liquid helps in the separation of the acceptable fibers from the undesired constituent so that a large proportion of the acceptable fibers is fed through the cylindrical screen and a minimal amount of undesired material flows to the bottom of the annular channel as part of the rejects.

Abstract: A method and apparatus for dewatering of cellulose pulp or other fiber suspensions. A suspension of relatively low solids concentration is passed into a sealed housing through an inlet, substantially filling the housing. The suspension is dewatered by bringing it into contact with perforated surfaces of a pair of drums or the like mounted for rotation about a vertical axis within the housing. Liquid from the suspension passes into an interior drum chamber, and at least a portion thereof is expelled from the housing through a liquid outlet. After passing a nip point between the two drums, the suspension has a higher solids concentration than the desired product suspension, and an amount of liquid is added thereto from the drum interior to dilute it to the final concentration.

Abstract: In a screening machine of the type having a perforated cylinder through which the material being screened is passed and a rotor for maintaining the cylinder perforations open, failure of the cylinder due to torsional forces imposed on it by rotation of the rotor is prevented by providing several beam-like cantilevers which extend longitudinally of the cylinder and resist the twisting, torsional forces imposed on the cylinder during screening operations. Intermediate reenforcing rings, which are designed to withstand radially directed loads imposed on the cylinder, are restrained against movement longitudinally of the cylinder by means of clips which are welded to the cantilevers on opposite sides of each of the rings. The cantilevers, therefore, also serve as an area on the cylinder to which the clips can be welded, eliminating the necessity of making welds at undesirable locations near perforated portions of the cylinder.

Abstract: Screening apparatus for paper fiber stock and other fiber suspension is especially designed to handle relatively suspension containing stringy material. A perforate screen cylinder forms the outer wall of the supply chamber for the stock to be screened, and a rotor operates in the supply chamber and includes vanes which travel in spaced relation with the inner wall of the screen cylinder. These vanes are supported on the rotor hub by imperforate arms of substantial axial extent which act as propeller blades to maintain a high rate of circulation of the stock within the supply chamber and also to direct the stock toward the reject collecting chamber from which stock is continuously discharged at a high volumetric rate approaching or equal to the rate of discharge of accepted stock. Helical ribs on the inner surface of the screen cylinder aid in channeling the flow of reject-containing stock toward the reject outlet.

Abstract: A classifying apparatus is disclosed for use in separation of different portions of fibrious suspensions such as waste papers stock coming from a pulper. The apparatus is a unit comprising a vortex cleaner combined with a pressure screen. It includes a cylindric rotor whose circumferential portion carries agitating rods for the screen, the bottom of the rotor being provided with means for intensifying the motion of the stock fed into the vortex cleaner portion of the apparatus. The cylindric rotor defines a comparatively narrow gap between the rotor and the screen cage.

Abstract: A negatively pressurized rotating hollow foil pulse device having a curved leading surface, a V-shaped trailing surface and one or more openings in the trailing surface is placed in close proximity to a pulp screen for removing oversized pulp reject material. A rotating disc seal separates a reject compartment from the material to be screened.

Abstract: A paper fiber treatment system utilizes a screw revolving in a perforated cylinder as a tailings screen in place of conventional vibratory or other screens to separate undefibered fibrous materials or other undesirable solids from the free fibers. The tailings screen may be used, for example, in an otherwise conventional fiber treatment system to screen paper stock, downstream from a pulper for pulping waste paper or refuse containing a high percentage of paper fibers, or downstream of a digester for separating knots or other undefibered wood particles from the cooked fibers ejected from the digester.