Abstract: In a pulp digester for continuous cooking under raised pressure and temperature of fiber material in a vertical digester (1), input of fiber material and cooking liquid takes place at the top of the digester, withdrawal of spent cooking liquor is carried out from at least one digester screening arrangement (1D) between the top and the bottom of the digester, and fiber material is fed out from the bottom (1C) of the digester, and at least one screening arrangement (2) in the lower half of the digester, wherein at least one of said screening arrangements (1, 2) has at least one screen element (2A) of which the main configuration is of angular shape, preferably rectangular, most preferred square, having a screen face (3A) of which the total area is less than 1 m.sup.

Abstract: A device for treating a preferably cellulose-containing suspension, comprising a housing (1) on a stand (2).

Abstract: In the continuous cooking of comminuted cellulosic fibrous material (e.g. wood chips) to produce paper pulp, the material is subjected to a minimum of mechanical action, especially under high temperature and pressure conditions, so as to increase the quality of the pulp. Also, even for large digesters the uniformity of treatment is enhanced, and scaling may be reduced while energy efficiency is increased. Material is fed without significant steaming to a feeder screw within a perforated cylinder mounted at the bottom of an impregnation vessel. The material flows upwardly in the impregnation vessel, with screens adjacent the top of the vessel thickening the slurry before it is discharged into the top of a continuous digester. The discharge from the impregnation vessel to the continuous digester is made with a minimum of mechanical action on the pulp. The impregnation vessel may be disposed within, and concentric with, the digester, or it may located exteriorly of the digester and supply more than one digester.

Abstract: An apparatus is disclosed for treating lignocellulosic materials, comprising an enzymatic conversion zone adapted to enzymatically convert alcohol to aldehyde and hydrogen peroxide, a delignification zone, a device for transferring an effluent comprising aqueous hydrogen peroxide from the conversion zone to the delignification zone, a chopper for adding chopped lignocellulosic material to the delignification zone, a separator for separating solid delignified material in the delignification zone from a liquid, and a fermenter adapted to grow alcohol oxidase-producing yeast, and means for transferring alcohol oxidase from the fermenter into the conversion zone.

Abstract: In the continuous cooking of comminuted cellulosic fibrous material (e.g. wood chips) to produce paper pulp, the material passes upwardly in an impregnation vessel which is within and concentric with a continuous digester and open at the top to digester pressure. At the top of the impregnation vessel, a solids/liquid separator (a screw within a screen cylinder) is provided. Separated liquid is returned in a conduit adjacent the exterior of the impregnation vessel, and open at the top to digester pressure, and passes out the bottom of the digester. The impregnation vessel is welded to the bottom of the digester, and the bottom of the digester is generally hemi-spherical, and substantially devoid of packings.

Abstract: Enhanced uniformity of treatment of the material with a treatment liquid in a continuous treatment vessel, is provided. The invention is particularly applicable to the treatment of comminuted cellulosic fibrous material to produce paper pulp, specifically for the digesting (kraft or sulfite, or solvent pulp processing) of wood chips to produce paper pulp. The vessel has at least one annular screen divided into at least four arcuate screen segments disposed around the internal periphery of the vessel, and a first liquid having treatment properties, and a second, spent liquid, are utilized in the treatment. A second liquid is withdrawn through at least a first of the arcuate screen segments while simultaneously the first liquid through or adjacent at least a second of the arcuate screen segments opposite the first screen segment. The various screen segments are operated, and at rest, in sequence to provide the uniformity of treatment.

Abstract: A wall means intended for apparatus for separation of a liquid-containing portion from a liquid-containing particle material which is fed through the apparatus in a predetermined direction (A). The wall means comprises a plurality of bar profiles defining continuous slots between them to allow through the liquid-containing portion. According to the invention each bar profile has on its inner side facing the liquid-containing particle material a ridge portion extending between the ends of the bar profile and being provided with two continuous guide surfaces which, as seen in a cross section of the rod profile, are inclined in relation to the drainage direction (B) of the liquid-containing portion through the adjacent slot. Furthermore, the inclined guide surfaces in their longitudinal direction are disposed to coincide with the predetermined direction of feed (A) of the liquid-containing particle material in order to influence the liquid-containing particle material to maintain this direction of feed (A).

Abstract: A process for the continuous digestion of cellulosic fiber material is described wherein the material is impregnated with liquid in a closed system comprising a concurrent flow zone and a countercurrent flow zone, the liquid in the concurrent flow zone including black liquor and possibly white liquor and the liquid in the countercurrent flow zone including white liquor. Liquid is withdrawn from the impregnation system at a point located between the concurrent flow zone and the countercurrent flow zone. Besides white liquor a predetermined amount of black liquor is added to the countercurrent flow zone in order to obtain a high liquid to wood ratio in the inlet of the digester.

Abstract: A method and apparatus for enhancing knot transport in a knot drainer has a provision for decreasing tangential velocity of the feed slurry in the inlet chamber, a hydrodynamic force reduction provision in the screening chamber, and a provision for increasing the ratio of circumferential friction forces to axial friction forces in a housing extension above the screening chamber. This drastically reduces frequency of knot transport interruptions which would otherwise occur in the knot drainer, thereby improving knot drainer performance efficiency.

Abstract: In a pressure diffuser, clogging of the tapered inlet passageway at the bottom of the vessel is minimized by providing a number of lubricating fluid introducing nipples disposed circumferentially around the annular passageway. The nipples introduce lubricating fluid so that it flows upwardly along the inner wall of the vessel. The vessel inner wall and the bottom support for the screen at the passageway are polished and free of projections, so that friction is minimized. The nipples are provided in sets that are staggered so that a nozzle is placed about every 15.degree. around the circumference of the vessel, and a common annular header--mounted on the support legs of the vessel--provides the lubricating fluid. Should screen movement slow as a result of paper pulp properties near the screen bottom support, the flow rate of lubricating liquid can be increased so as to significantly dilute the pulp at the passageway until slow movement of the screen is overcome.

Abstract: An apparatus for treating a pulp suspension in a screening plant of a pulp mill wherein impurities are separated from defibered pulp by screening and/or cleaning, the cleaned pulp is thickened, the impurities are further treated in the screening plant by screening and defibering the accept fiber material for further screening and thickening and further impurities are removed from the screening plant after various screening stages, the apparatus including means for 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 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 process for the continuous digestion of cellulosic fiber material is described wherein the material is impregnated with liquid in a closed system comprising a concurrent flow zone and a countercurrent flow zone, the liquid in the concurrent flow zone including black liquor and possibly white liquor and the liquid in the countercurrent flow zone including white liquor. Liquid is withdrawn from the impregnation system at a point located between the concurrent flow zone and the countercurrent flow zone. Besides white liquor a predetermined amount of black liquor is added to the countercurrent flow zone in order to obtain a high liquid to wood ratio in the inlet of the digester.

Abstract: In a continuous digester for paper pulp (comminuted cellulosic material), abrupt variations in high pressure steam flow are minimized. First and second vertically spaced annular screens are provided in a vertical vessel. Each has an annular header associated with it and first and second circumferentially spaced liquid outlets associated with each header. The first outlet for the first screen is generally vertically in line with the first outlet for the second screen, and the second outlet of the first screen is generally vertically in line with the second outlet of the second screen. Simultaneous withdrawal of liquid from the first outlet of the first screen and the second outlet of the second screen takes place, and then is terminated, and then simultaneous withdrawal of liquid from the second outlet of the first screen and the first outlet of the second screen takes place, and then is terminated. This withdrawal sequence is repeated continously.

Abstract: Screen cylinders, and methods of making the same for use in removing contaminant particles from papermaking stock, have a seamless cylinder body and the openings or slots therethrough are formed by directing a focused laser beam at an outer surface while focusing the beam intermediate the outer an dinner surfaces to form an opening or slot with tapered walls. Wear bars may be applied to the inside surface as a bead of weld material. The seamless cylindrical body is formed by centrifugal casting or by cold roller extrusion.

Abstract: In a paper pulp treating vessel, such as a pulp thickener or diffuser, the screens are backflushed by reciprocating an internal piston utilizing an internally mounted hydraulic cylinder. The screens are supported by conduit arms having a central hub, and the hydraulic cylinder is mounted directly on top of the hub, with the backflushing cylinder mounted below the hub. Hydraulic lines lead from exteriorly of the vessel to the hydraulic cylinder within the vessel, and a sealing conduit is mounted surrounding the hydraulic lines. The sealing conduit extends to a point above the top of the vessel to act as an indicator if hydraulic fluid leaks in the vessel. A flexible bellows is connected between the sealing conduit and the hydraulic cylinder to allow tilting action between the arms and the top of the vessel.

Abstract: Extended delignification of kraft pulp in a pressure diffuser allows a pulp mill with a digester (e.g. continuous digester) to increase its production capacity without building a new line, or to decrease its demand in its bleach plant, or to increase the strength of softwood pulp it produces. Comminuted cellulosic fibrous material is kraft cooked to produce kraft pulp having a blow temperature over about 300.degree. F. The pulp is diffusion treated in the first stage of a pressure diffuser to replace the water around the pulp with delignifying liquor. The liquor has a dissolved lignin concentration of less than 12% (optimally less than about 4%), has an effective alkali concentration of at least 2 gm/l (preferably 8-55 gm/l), and a temperature of at least about 300.degree. F. Treating the pulp with the delignifying liquor significantly reduces the K-number (e.g. on the order of about 5). After extended delignification, the pulp is washed in subsequent stages of the pressure diffuser.

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 pressure diffuser includes in a liquid-tight pressurized vessel a vertical screen and which screen and vessel wall define first and second interior volumes for transmitting pulp from a pulp inlet to a pulp outlet and receiving displacement (e.g. wash or bleach) liquid transmitted from headers through the pulp. The screen ends have different cross-sectional areas, and quick movement of the screen effects backflushing. The volumes are segregated by a vertical, generally cylindrical, screen. A chamber is provided in communication on opposite sides of a piston therein with the pulp adjacent the pulp inlet and the extracted liquid. By displacing the piston immediately prior to rapidly moving the screen vertically to effect backflushing through the screen, the pulp pressure on the screen is being reduced and at the same time a volume is made available adjacent the pulp inlet in the chamber thus avoiding pressure shocks and compaction of the pulp adjacent the inlet caused by the movement of the screen.

Abstract: A screen plate and method of making a screen plate for the pressure screening of papermaking stock in pressure screening apparatus includes slots which have been cut therethrough by a machining laser beam focused at the inlet side of the plate, to provide slots with nearly straight walls with minimum taper, and which are recast and have a "glassy" appearance by reason of the melting and resolidification of the immediate wall surface, to provide a low friction path for the stock. Straight, curved and inclined or slanted slots are disclosed including slots which are at a diagonal to the axis of the cylinder. Slots or openings are disclosed which are inclined to a radius line therethrough both with and against the direction of flow of the stock along the inlet surface. Wear bars are applied to the plate for coaction with the rotating foils on the screening apparatus, in the form of strips of weld material of high hardness applied directly to the plate.

Abstract: The screens of a pulp treating vessel, such as a paper pulp thickener, or diffuser, are back flushed in a simple yet effective manner. The screens are mounted to a supporting conduit within a vertical vessel, and a cylinder is connected at one open end to the conduit, and the other open end is disposed within the pulp inside the vessel. A piston is mounted within the cylinder and relative movement between the piston and cylinder is effected periodically in order to force liquid from within the cylinder into the conduit and out the screens, backflushing the screens and preventing clogging. Since no additional volume of liquid is added to the vessel during backflushing, no surge occurs in the vessel. Conventional accumulators, on/off valves, and the like can be eliminated while--in the case of diffusion washing--efficiency can be increased as much as 20-30% and capacity increased as much as about 15%.

Abstract: A pressure diffuser for paper pulp includes a vertical pressurizable liquid-tight vessel having a pulp inlet at the bottom and a pulp outlet at the top. One or more ring shaped screen elements providing first and second concentric screen surfaces, are vertically mounted within the vessel. A number of radially extending header arms mount the screen elements for movement in the vessel and in fluid communication with it. A first linear actuator effects reciprocation of the arms. A cylinder, open at both ends, is affixed to the arms and extends both above and below them, and a piston is disposed within the cylinder, below the arms. A second linear actuator is operatively connected to the piston to effect reciprocation of the piston in the cylinder. A guiding conduit surrounds the open end of the cylinder above the arms and guides reciprocation of the cylinder and transports liquid from the arms to an effluent outlet.

Abstract: For bleaching cellulose pulp or a fraction thereof, e.g. reject pulp, the cellulose pulp or fraction, having a concentration of 0.5-10%, preferably 3-6%, is introduced into a screw press comprising at least a first (47) and a second (48) dewatering zone, is dewatered in the first zone to a concentration of 20-40%, whereupon a liquor of bleach chemicals is introduced centrally into the pulp which, during continued treatment, is dewatered in the second zone to a discharge pulp concentration of 15-50, preferably 15-30%, the liquid pressed out of the second zone, together with fresh bleach chemicals, being returned to the pulp in the screw press as liquor of bleach chemicals.

Abstract: A screen plate and plate and method of making a screen plate for the pressure screening of papermaking stock in pressure screening apparatus includes slots which have been cut therethrough by a machining laser beam focused at the inlet side of the plate, to provide slots with nearly straight walls with minimum taper, and which are recast and have a "glassy" appearance by reason of the melting and resolidification of the immediate wall surface, to provide a low friction path for the stock. Straight, curved and inclined or slanted slots are disclosed including slots which are at a diagonal to the axis of the cylinder. Slots or openings are disclosed which are inclined to a radius line therethrough both with and against the direction of flow of the stock along the inlet surface. Wear bars are applied to the plate for coaction with the rotating foils on the screening apparatus, in the form of strips of weld material of high hardness applied directly to the plate.

Abstract: The screens of a pulp treating vessel, such as a paper pulp thickener, or diffuser, are back flushed in a simple yet effective manner. The screens are mounted to a supporting conduit within a vertical vessel, and a cylinder is connected at one open end to the conduit, and the other open end is disposed within the pulp inside the vessel. A piston is mounted within the cylinder and relative movement between the piston and cylinder is effected periodically in order to force liquid from within the cylinder into the conduit and out the screens, backflushing the screens and preventing clogging. Since no additional volume of liquid is added to the vessel during backflushing, no surge occurs in the vessel. Conventional accumulators, on/off valves, and the like can be eliminated while--in the case of diffusion washing--efficiency can be increased as much as 20-30%, and capacity increased as much as about 15%.

Abstract: In a falling film exchanger, a screen arrangement for preventing solid particles in the liquid to be heated from plugging liquid distribution outlets of a perforated liquid distributing tray or reaching the heating surface of the heat exchanger.

Abstract: Comminuted cellulosic fibrous material, such as wood chips, are treated in a continuous digester to produce paper pulp or the like in a manner providing completely uniform treatment of the chips. The chips are introduced in a feed liquid slurry into the top of the digester having a plurality of annular screen systems each set vertically spaced from the other sets. At each screen set a plurality of nozzles are provided circumferentially spaced around the digester, each nozzle cooperating with only a particular radial segment of the screens. Withdrawal of liquid through the nozzles is practiced so that liquid is being withdrawn substantially through only one nozzle at a time, and it is being withdrawn at the same radial segment of the digester at each screen set at any particular point in time, with progressive switching in a circumferential sequence of the nozzles through which liquor is being withdrawn.

Abstract: An apparatus for fiberizing and screening of fibrous material, which comprises of a rotating drum (1) the drum wall (2) of which consists of a non-perforated (7) and a perforated (8) part. The non-perforated part in the inlet end of the drum is separated from the perforated part in the outlet end of the drum by means of a partition wall (9) having an opening (10). The height (h) of the partition wall varies so that a periodical overflow is achieved when the drum rotates.

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: In vertical vessels, particularly continuous pulp digesters, fibrous material suspended in liquid passes downwardly past screens through which treatment liquid is withdrawn. The screens are reciprocated vertically up and down utilizing a piston and cylinder assembly, operatively connected by a two-way valve to a source of fluid under pressure or a vent. The piston and screen are connected by a universal joint, and the screen is positively guided during movement. The piston is vertically above the screen and the screen moves downwardly under pressure from the pump, and returns upwardly, under the influence of interior digester pressure, during normal digester operation.

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: Comminuted cellulosic fibrous material, such as wood chips, are treated in a continuous digester to produce paper pulp or the like in a manner providing completely uniform treatment of the chips. The chips are introduced in a feed liquid slurry into the top of the digester, with a swirling action, and establish a vertical column in the digester having a substantially horizontal top, with some liquid between the top of the digester and the top of the chips. Below the top of the chips the feed liquor is withdrawn through a first set of withdrawal screens, and recirculated to entrain other chips to feed them to the top of the vessel. At other vertically spaced areas of the digester other screens are provided for withdrawing, cooking, quench, washing, and like liquors, and effecting recirculation thereof. At each screen set a plurality of nozzles are provided circumferentially spaced around the digester, each nozzle cooperating with only a particular radial segment of the screens.

Abstract: A process and apparatus for producing pulp from impregnated cellulose-containing starting materials such as wood, straw, grass, waste materials etc. in a compacting apparatus comprising a shell (1) and two mutually opposite pistons (4, 4') contained in said shell. The material to be compacted is disposed between said pistons and constitutes a resistive electrical load. The pistons are movable relative to each other and the shell is movable relative to the pistons. The impregnated starting materials are digested at a relatively low hydromodulus of 0.5 to 2 with a direct action of heat on the impregnated starting materials in the compacting apparatus at a digesting temperature of 160.degree. to 300.degree. C. The digesting times are short and depend on the digesting temperature.

Abstract: A method and apparatus for selectively withdrawing liquor from digester cooking screens for controlling the temperature in continuous digesters. First and second pairs of screens, with cooperating headers, are provided, and first and second outlets spaced circumferentially around the digester are associated with each header. Each header provides a circumferential cavity free of dividing members. Within each pair of screens withdrawal is practiced so that each header is rested during each ultimate withdrawal step, and the side from which the liquor is drawn each successive withdrawal step that the same header is used is alternated. In practicing the invention, header blockage caused by deposited debris and scale is minimized and increased uniformity and improved product quality result.

Abstract: A diffusion washer and/or thickener assembly is provided that is greatly simplified. A number of withdrawal screens and fluid introducing structures are provided supported by spider arms which comprise conduits for introduction of liquid into and withdrawal of liquid from an elongated upright hollow vessel in which the assembly is disposed. The conduit means, with attached screen structures, is reciprocated up and down by a single linear actuator located preferably above the vessel and within the cross-sectional area thereof so that the wall of the vessel need not be penetrated by the conduits. The screens and fluid introducing structures remain stationary with respect to each other during reciprocation. A number of wiper blades, which may be operated by a single linear actuator, are provided at the top of the vessel for moving upwardly flowing pulp into withdrawal conduits surrounding the vessel periphery.

Abstract: Thickening of paper pulp, or a like suspension, is effected prior to feeding the pulp to an apparatus utilizing stationary screens for effecting washing, bleaching, or further thickening of the pulp. The stationary screens are mounted in a top portion of a vertical-axis vessel, and a plurality of radially extending rotating hollow arms, with annular screens mounted on them, is provided in the bottom of the vessel to effect thickening of the suspension from, for example, 11/2% consistency to about 9-14% consistency. Extraction from the hollow arms is provided through conduits extending vertically through a hollow shaft for rotating the arms, and a filtrate valve is also mounted within the hollow shaft in operative communication with the filtrate conduits, and includes a valve member which is rotatable in a different direction, and at a different speed, than the hollow shaft.

Abstract: In a paper making process the liquid fraction of wood pulp stock liquor is sampled between the bleaching and caustic extraction stages and after caustic introduction to regulate the amount of caustic introduced into the pulp stock liquor. A particular sampling device with a lower pressure chamber extracts that stock liquor from the periphery of a higher pressure pipe and passes the sample to previously known continuous testing apparatus. A particular double screen type interfacing joins the sampling device and pulp stock to allow liquor extraction without excessive wear or plugging of the interface.

Abstract: A method and apparatus for effecting washing, bleaching, or thickening, etcetera of paper pulp of the like utilizes stationary screens, yet provides efficient treatment without significant screen clogging. Pulp introduced into the bottom of a cylindrical upright vessel is caused to flow in particular radial segments and channels. Introduction of pulp into all channels of a particular radial segment, extraction of withdrawn liquid from the radial segments, removal of treated pulp from the top of the vessel, and the introduction of treating liquid between the stationary screens, are coordinated so that uniform treatment of the upwardly flowing pulp results.

Abstract: A diffusion washer and/or thickener assembly is provided that is greatly simplified. A number of withdrawal screens and fluid introducing structures are provided supported by spider arms which comprise conduits for introduction of liquid into and withdrawal of liquid from an elongated upright hollow vessel in which the assembly is disposed. The conduit means, with attached screen structures, is reciprocated up and down by a single linear actuator located preferably above the vessel and within the cross-sectional area thereof so that the wall of the vessel need not be penetrated by the conduits. The screens and fluid introducing structures remain stationary with respect to each other during reciprocation. A number of wiper blades, which may be operated by a single linear actuator, are provided at the top of the vessel for moving upwardly flowing pulp into withdrawal conduits surrounding the vessel periphery.

Abstract: A digester strainer locking assembly for strainer panels supported interiorly of a generally cylindrical digester vessel wherein a socket member receives a clamp lock member and a lock member all wedgingly interrelated to clamp the panels releasably in place.

Abstract: A method and apparatus for screenless treatment of cellulose fiber material without channeling of treatment liquid through a fiber material column being treated. An inner vertical vessel extends into an outer vertical vessel which has a larger diameter than the inner vessel, and an annular space in the outer vessel is defined by a portion of the inner vessel extending into the outer vessel. At least three baffles extend through the annular space into the area of the outer vessel below the inner vessel to define at least three distinct flow areas, and an outlet nozzle is provided in each of the flow areas. Liquid is withdrawn from the annular space through at least two of the flow areas, while liquid is backflushed into one of the flow areas.

Abstract: A process and apparatus for automatically maintaining the moisture content in a continuously conveyed batch of porous materials is described. The porous material is continuously fed through a treatment tank, wherein it is contacted with a liquid to be absorbed therein. The moisture content of the material is continuously monitored as a direct function of the combined weight of the material and the treatment tank to generate correction signals. The correction signals are utilized to vary the dwell times (up or down) of the porous material in the treatment tank. By varying the dwell times the porous material is contacted by the treating liquid for either larger or shorter periods until the weight of the tank and material therein returns to the weight desired. Thus, the moisture content of the porous material is continuously adjusted to a substantially constant value.

Abstract: Apparatus for the production of a lignocellulose material from chips, sawdust, chopped plants, bark, small fibres comprising a vertical column with a series of successively-mounted horizontal perforated plates partly abutting upon the inner surface of the column; at the free ends of said plates retaining baffles are secured for partial entrapment of coarse particles of the product; a clearance is provided between the baffle and inner surface of the column and the plates are disposed relative to each other so that baffles of each successive plate are located diametrically opposite to the baffles of each preceding plate thus forming a zigzag labyrinth along the total height of the column for increasing the time of contact of coarse particles of the raw materials with the oxygen-containing gas and alkaline reagent.A pulsator means is operably connected to the column for setting liquid reagents in the column into reciprocating vertical motion.

Abstract: Apparatus and method for digestion of cellulose material in a continuous digestion process, that do not require screens in the outlet of the digesting zone. Cellulose chips and digesting liquid at relatively low temperature are introduced into a relatively long and thin cylindrical impregnation vessel, having a first diameter. The chips from the impregnation vessel pass into a digestion vessel having a second diameter substantially greater than the first diameter, the outlet for the impregnation zone into the digestion vessel being disposed well into the digestion vessel and below an outlet(s) disposed in the top of the digestion vessel, and form a chips column in the digestion vessel.

Abstract: A method and apparatus for the thickening of a suspension of comminuted fiber material and liquid. A reciprocal screen assembly having a variable volume interior chamber is mounted for movement along the axis of a container through which suspension to be dewatered flows. Mechanical apparatus, such as a hydraulic cylinder actuated rod, moves the screen assembly in either the direction of flow of suspension in the container, or in the direction opposite thereto, and the screen assembly is relatively rotatable with respect to the container. During movement of the screen assembly in the direction of flow of the suspension (at about the same velocity as the suspension flow), liquid passes through the screen assembly into the interior chamber, and is expelled from the container. The screen assembly is moved more quickly in the direction opposite to the direction of suspension flow, and the variable volume of the interior chamber thereof decreases quickly so that backflushing of the screen assembly is effected.

Abstract: A strainer construction including a generally rectangular screen section for the interior of a walled vessel equipped with unique hook receiving means for supporting the same and facilitating expansion of the number of screen sections.

Abstract: A method and apparatus for dewatering a suspension of comminuted fiber material and liquid. A suspension is passed in a given direction in a container of generally circular cross-section having a hydraulic piston mounted generally concentrically therein. There are no movable components extending between the piston and the walls of the container in which it is disposed, therefore leakage from the container is minimized. The piston has screens for separating liquid from the suspension associated therewith, and is movable in the same direction as the suspension flow during removal of some liquid from the suspension, and is movable in a direction opposite to the direction of fluid flow to facilitate cleaning of the screens and to return the piston to a position wherein it can move in the direction of flow again.

Abstract: A continuous digester in which liquor is drained, at various levels, through a screen into a compartment formed by half rings attached to the interior of the digester. The compartment is provided with rotating vanes, which backwash the screen by pulsing liquid therethrough. The digester includes a lower cone, provided with an impeller and compartment for introducing and circulating liquor for "cold blow" of product.