Abstract: Chemical cellulose pulp is made from sawdust utilizing a static down-flow retention vessel. By adding steam and cooking liquor to a flow of sawdust a heated slurry, at a cooking temperature of about 250-350° F., is produced. The heated slurry is, at superatmospheric pressure, moved downwardly in the static down-flow retention vessel while cooking temperature is maintained, for a time period of about 0.5-6 (preferably 1 to 3) hours, the slurry having a consistency of about 5-30%. At superatmospheric pressure, without significant reduction in pressure from the retention vessel, the slurry is cooled to well below cooking temperature by diffusing cooling liquid through it, as in a conventional pressure diffuser. The discharge from the retention vessel is preferably substantially solely gravity action (e.g. using a discharge with single convergence and side relief).

Abstract: The release of malodorous TRS-containing gases from a comminuted cellulosic fibrous material feed system for a digester is minimized utilizing a particular arrangement associated with a pressure isolation device. Material is fed through the pressure isolation device and the pressure of the material increases from the inlet to the outlet, and the material is discharged from the pressure isolation device into a treatment vessel, such as a horizontal steaming vessel. Malodorous gases from the pressure isolation device are discharged substantially independently of the material discharged from the isolation device, and at least some of the malodorous gases discharged from the pressure isolation device are pressurized (e.g. in an eductor or thermocompressor) and reintroduced into the flow of cellulosic material downstream of the pressure isolation device (for example into the horizontal steaming vessel or a vessel downstream of it).

Abstract: A method and apparatus for heating cellulose pulp with steam are provided. Low-pressure (e.g. 3-5 bar (abs.)) steam is supplied into the pulp flowing as a plug flow in such a way that in the flow direction of the pulp, before supplying the low-pressure steam, the pulp is pressurized so that the pulp pressure at the point of the steam introduction is lower than the pressure of the available steam. After the steam is introduced the pulp is mixed with a pressure-raising mixer (such as a fluidizing centrifugal pump) to divide the steam evenly into the pulp and/or to equalize the temperature of the pulp.

Abstract: In the feeding of a slurry of comminuted cellulosic fibrous material to a digester (continuous or batch) in the production of chemical pulp, one of the tanks used in the feed system (which preferably includes a high pressure feeder) may be eliminated without consequent loss of its function by providing a single tank with the combined functions of controlling the level of liquid in a slurrying conduit which supplies slurry to a slurry pump, and storing and substantially continuously supplying liquid to a make-up liquid pump connected to the digester. The single tank preferably surrounds the slurrying conduit and is substantially concentric, and in liquid communication, with it. A gap of 3-48 inches may be provided between the bottom of the conduit and a connection to the slurry pump. A screen or strainer may be provided in the gap, which is substantially surrounded by the tank.

Abstract: Chemical cellulose pulp is made from sawdust utilizing a static down-flow retention vessel. By adding steam and cooking liquor to a flow of sawdust a heated slurry, at a cooking temperature of about 250-350° F., is produced. The heated slurry is, at superatmospheric pressure, moved downwardly in the static down-flow retention vessel while cooking temperature is maintained, for a time period of about 0.5-6 (preferably 1 to 3) hours, the slurry having a consistency of about 5-30%. At superatmospheric pressure, without significant reduction in pressure from the retention vessel, the slurry is cooled to well below cooking temperature by diffusing cooling liquid through it, as in a conventional pressure diffuser. The discharge from the retention vessel is preferably substantially solely gravity action (e.g. using a discharge with single convergence and side relief).

Abstract: Chemical pulp is produced from a slurry of comminuted cellulosic fibrous material using a beneficial additive such as AQ, or polysulfide. In the first treatment zone the effective alkali concentration and temperature conditions are such so that substantially no alkali degradation of the cellulose occurs, but so that the material is effectively impregnated with the additive. Then the material is treated with an alkaline cooking liquor, at cooking temperature, to produce a chemical cellulose pulp with higher yield or strength than if the low temperature, low alkali, additive pretreatment was not practiced. Typical alkali and temperature conditions in the first zone are less than 10 g/l expressed as NaOH; and between about 80-130° C., e.g. about 80-110° C. The first zone is preferably a feed system (which may include a separate impregnation vessel) for a continuous digester, while cooking is in a continuous digester.

Abstract: A revolver valve includes a housing with a cylindrical inner chamber, and a pair of end caps respectively attached to each end of the housing. One of the end caps includes an inlet opening and the other end cap includes an outlet opening. A cylindrical rotor body is rotatably disposed within the inner chamber of the housing. The rotor body includes a pair of end faces respectively positioned closely adjacent to the end caps, and a plurality of longitudinally extending cylinders extending between the end faces. Each cylinder is positioned generally concentrically about an axis of rotation of the rotor body, whereby the plurality of cylinders are sequentially disposed in communication with the inlet opening and the outlet opening during rotation of the rotor body within the inner chamber during use. The revolver valve is preferably used in a fiber stock preparation system in conjunction with a fiber loading apparatus having a pressurized vessel.

Abstract: A pulp bleaching line has an initial stage using gaseous bleaching reagent followed by its subsequent stages without intervening washing or pumping steps. The pulp is transported from the initial stage through a mixer in which the pulp is heated and/or dosed with bleaching chemicals and through the subsequent stage by retained gas pressure developed in the initial stage. A portion of the retained gas may be separated and purged from the mixer through a pressure regulating device to optimize pressure for processes which follow the mixer/heater. This permits elimination of a washer and pump normally provided between the initial reactor and subsequent bleaching stage.

Abstract: Dense, tramp material, is efficiently separated in a comminuted cellulosic fibrous material feed system, for example in a chemical cellulose digester feed system, in a simple but effective matter. By merely utilizing a generally vertical conduit and a slurry flow within it (which may be augmented by high speed liquid introduction), that is caused to turn in a radiused path, centrifugal force allows separation of the tramp material into a cavity beneath the radius transition without requiring any mechanical element to engage the slurry. Appropriate purges, baffles, and discharge mechanisms may be provided. Alternatively, a tramp material separator may be built into an otherwise conventional metering screw in a digester feed system, or one or more centrifugal separators can be provided downstream of the slurry pump in a chip slurry transport system or digester feed system.

Abstract: In a cellulose pulp handling vessel having a first diameter material storing or treating portion above a second diameter discharge which is at least 20% less than the first diameter, reduced compression of the material and reduced power requirements of an agitator (if used), compared to prior art constructions are provided. A first transition, preferably a substantially smooth interior surface substantially frusto-conical transition, is provided between the first and second diameters. A second single-convergent transition may be provided above the first transition. A rotating agitator with at least two arms and associated paddles may be mounted for rotation in the transition about a substantially vertical axis for agitating the material in the transition. If desired, the transition may be moved, such as with a vibrator or oscillator. The invention is particularly suitable for pulp digesters and impregnation vessels.

Abstract: In a cellulose pulp handling vessel having a first diameter material storing or treating portion above a second diameter discharge which is at least 20% less than the first diameter, reduced compression of the material and reduced power requirements of an agitator (if used), compared to prior art constructions are provided. A first transition, preferably a substantially smooth interior surface substantially frusto-conical transition, is provided between the first and second diameters. A second single-convergent transition may be provided above the first transition. A rotating agitator with at least two arms and associated paddles may be mounted for rotation in the transition about a substantially vertical axis for agitating the material in the transition. If desired, the transition may be moved, such as with a vibrator or oscillator. The invention is particularly suitable for pulp digesters and impregnation vessels.

Abstract: Dense, tramp material, is efficiently separated in a comminuted cellulosic fibrous material feed system, for example in a chemical cellulose digester feed system, in a simple but effective matter. By merely utilizing a generally vertical conduit and a slurry flow within it (which may be augmented by high speed liquid introduction), that is caused to turn in a radiused path, centrifugal force allows separation of the tramp material into a cavity beneath the radius transition without requiring any mechanical element to engage the slurry. Appropriate purges, baffles, and discharge mechanisms may be provided. Alternatively, a tramp material separator may be built into an otherwise conventional metering screw in a digester feed system, or one or more centrifugal separators can be provided downstream of the slurry pump in a chip slurry transport system or digester feed system.

Abstract: The release of malodorous TRS-containing gases from a comminuted cellulosic fibrous material feed system for a digester is minimized utilizing a particular arrangement associated with a pressure isolation device. Material is fed through the pressure isolation device and the pressure of the material increases from the inlet to the outlet, and the material is discharged from the pressure isolation device into a treatment vessel, such as a horizontal steaming vessel. Malodorous gases from the pressure isolation device are discharged substantially independently of the material discharged from the isolation device, and at least some of the malodorous gases discharged from the pressure isolation device are pressurized (e.g. in an eductor or thermocompressor) and reintroduced into the flow of cellulosic material downstream of the pressure isolation device (for example into the horizontal steaming vessel or a vessel downstream of it).

Abstract: In a cellulose pulp handling vessel having a first diameter material storing or treating portion above a second diameter discharge which is at least 20% less than the first diameter, reduced compression of the material and reduced power requirements of an agitator (if used), compared to prior art constructions are provided. A first transition, preferably a substantially smooth interior surface substantially frusto-conical transition, is provided between the first and second diameters. A second single-convergent transition may be provided above the first transition. A rotating agitator with at least two arms and associated paddles may be mounted for rotation in the transition about a substantially vertical axis for agitating the material in the transition. If desired, the transition may be moved, such as with a vibrator or oscillator. The invention is particularly suitable for pulp digesters and impregnation vessels.

Abstract: A pulper in a stock preparation system includes a housing with a fiber inlet, at least one water inlet, at least one outlet and an inner chamber. A plurality of stationary pulping foils are attached to the housing and extend into the inner chamber. A rotatable shaft assembly extends through the inner chamber. The shaft assembly includes a shaft, an auger positioned around the shaft and relative to the fiber inlet and a plurality of movable pulping foils carried by and extending from the shaft. A conical valve is positioned in association with the outlet and is selectively movable to open and close the outlet.

Abstract: A walled passageway, having openings therein only at opposite, inlet and outlet ends thereof, has a shaft journalled therein. The shaft carries a screw thereon for moving shredded pulp through the passageway. The screw is foreshortened, having a length less than that of the passageway, and causes inlet-admitted pulp to form into a continuously moving pulp plug. The plug, albeit having some porosity, comprises a gas seal within the passageway, and inhibits any migration of downstream gas from escaping to the atmosphere via the passageway and the inlet thereof. In addition, a source of oxygen or such gas as is inert to any downstream process is controllingly admitted into the inlet to maintain an upstream pressure equal to, or greater than any downstream process pressure to insure against release of downstream gas into the atmosphere.

Abstract: A revolver valve includes a housing with a cylindrical inner chamber, and a pair of end caps respectively attached to each end of the housing. One of the end caps includes an inlet opening and the other end cap includes an outlet opening. A cylindrical rotor body is rotatably disposed within the inner chamber of the housing. The rotor body includes a pair of end faces respectively positioned closely adjacent to the end caps, and a plurality of longitudinally extending cylinders extending between the end faces. Each cylinder is positioned generally concentrically about an axis of rotation of the rotor body, whereby the plurality of cylinders are sequentially disposed in communication with the inlet opening and the outlet opening during rotation of the rotor body within the inner chamber during use. The revolver valve is preferably used in a fiber stock preparation system in conjunction with a fiber loading apparatus having a pressurized vessel.

Abstract: A cellulose pulp continuous digester (e.g. for producing kraft pulp) is operated so that it has an inverted top separator and is hydraulically filled to above the level of the inverted top separator, and may be substantially completely hydraulically full. A plurality of different liquor flows may be extracted from the inverted top separator, and an in-line drainer may be provided in a conduit through which liquid is extracted.

Abstract: By establishing a relatively flat, for example, non-sharply conical, top profile of wood chips in a treatment vessel (such as a chip bin), the chips will be more uniformly steamed or otherwise treated (or have the treatment time of the chips extended) compared to if a conventional sharply conical top profile is established in the treatment vessel. The relatively flat top profile of the chips in the treatment vessel is established by utilizing a plurality (typically at least three, and preferably four or more) individually controlled gates (typically having a substantially polygon shape, such as triangular). The gates are mounted below the inlet of chips into a treatment vessel so to deflect, not significantly affect, or substantially preclude the flow of chips past them into the vessel depending upon the positions of each.

Abstract: A feeding system for feeding comminuted cellulose containing material and liquid to a continuously operating treatment vessel. The feeding system comprises a chute, operating at a first pressure, a high pressure feeder sluices the material to a second pressure, that is higher than the first pressure, for further conveyance to the treatment vessel. The high pressure feeder also receives a return liquid flow from the treatment vessel at the second pressure and recirculates a recirculation flow to the chute. The high pressure feeder is in fluid communications, regarding both the liquid and the material, with the recirculation flow when any of the pockets of the high pressure feeder is in a location which corresponds to an outlet for the recirculation flow.

Abstract: An insert is bolted to the inlet of a wood chip digester to provide air exhaust during chip loading, and over pressure relief during chip processing. The insert has an upper flange which connects to an overhead chip valve, and a lower flange which mates with the top of the digester inlet. The insert has an outer cylindrical section extending between the upper flange and the lower flange and a lower conical section which extends downwardly into the digester. An inner cylindrical sleeve is positioned coaxially with, and joined to, the outer wall by a conical ring at the top, and is joined to the conical section at the bottom. The outer wall, the conical section, and the inner cylindrical sleeve form a sealed volume, which maybe partitioned into two parts. The first part has a sector between the outer wall and the inner cylindrical sleeve which is connected to a pressure relief fitting, a portion of the sector being porous for allowing pressure relief through the fitting.

Abstract: Pulp is effectively and simply fed into a pulp tower using at least one feed pipe having a number of openings that are spaced different distances from the bottom of the pulp tower. The opening through which the pulp being fed into the tower flows automatically changes depending on the level of the existing pulp in the tower. The feed pipe may have a wide variety of different configurations with openings formed or shaped in different manners, and baffles or similar guides can be used to uniformly spread the pulp being fed through the feed pipe onto the top surface of the existing pulp without mixing. This configuration allows the amount of pulp pumping energy to be minimized while still effectively feeding pulp into a tower.

Abstract: A pressure vessel 1 with an output arrangement 5, primarily for use with pulp bleaching using peroxide at high temperature and high pressure, comprising a pressure vessel housing 1, a first end 2, as well as an output arrangement 3 at a second end, whereby the output arrangement 3 comprises an output scraper 4 with at least one scraper arm 5, as well as at least one cleaning member 6, a driving arrangement 7, a driving axle 8, a bearing 9, a supporting structure 10 for the driving arrangement 7, a normally open first outlet 11, as well as, preferably, a normally closed second outlet, whereby the first outlet 11 and the second outlet 12 are provided in the wall 1 of the pressure vessel.

Abstract: A new and improved way of continuously cooking fiber material, wherein temperatures and alkaline levels are controlled to be maintained within specific levels in different zones of the digesting process in order to optimize chemical consumption and heat-economy and at the same time achieve very good pulp properties. The digesting process includes a top separator that separates the transport liquid from the fiber material and permits the fiber material to be exposed to the cooking liquid.

Abstract: The invention refers to a device for distributing suspensions, particularly pulp suspensions, in a tank 1, particularly a bleaching tower. It is characterized by a disc 6 being provided near the base 3 of the tank with at least one opening 7 so that the suspension is fed to the tank 1 and distributed in cycles over the tank cross-section near its base 3.

Abstract: A process and apparatus for treating and particularly bleaching pulp contacts a pulp with a gaseous reaction medium in a reactor tower. The pulp is fluffed and refined before being added to the pulp bed and then homogeneously permeated with the gaseous reaction medium to produce a uniformly treated pulp. A distribution device is included in the reactor to uniformly distribute the pulp in the reactor and form a homogenous pulp bed having a substantially even upper surface uniform bed depth.

Abstract: Dense, tramp material, is efficiently separated in a comminuted cellulosic fibrous material feed system, for example in a chemical cellulose digester feed system, in a simple but effective matter. By merely utilizing a generally vertical conduit and a slurry flow within it (which may be augmented by high speed liquid introduction), that is caused to turn in a radiused path, centrifugal force allows separation of the tramp material into a cavity beneath the radius transition without requiring any mechanical element to engage the slurry. Appropriate purges, baffles, and discharge mechanisms may be provided. Alternatively, a tramp material separator may be built into an otherwise conventional metering screw in a digester feed system, or one or more centrifugal separators can be provided downstream of the slurry pump in a chip slurry transport system or digester feed system.

Abstract: A cellulose pulp continuous digester (e.g. for producing kraft pulp) is operated so that it has the advantages of a hydraulic digester yet has a gas-filled zone over the liquid level. A slurry of chips and cooking liquor is introduced into the top of the digester vessel through an inverted top separator. A liquid level is established below the inverted top separator, and a chips level is established below the inverted top separator (above or below the liquid level). A gas-filled zone above the liquid level includes compressed gas, and is at a temperature of less than 160 (preferably less than 120).degree. C. and at a pressure of between 50-200 (preferably 80-150) psig. The digester may have a first diameter portion (about 3-5 meters) at the top and a second diameter portion (at least about seven meters) below the top, with the inverted separator in the first diameter portion, the liquid level in the first diameter portion, and the chips level in the second diameter portion.

Abstract: In a vertical digester for producing chemical pulp, or other vessel for treating a slurry of comminuted fibrous cellulosic material, the cost of manufacturing the shell is significantly reduced by eliminating the external step increases in the digester shell. The digester shell has a substantially constant internal diameter from just below the inlet to just above the outlet, screen assemblies being provided by an internal transition (e.g. conical) having an angle of convergence of less than 40.degree. (e.g. about 10-25.degree.) above each screen assembly so that the slurry flows through the transition without bridging or hang-up, and a step increase, or other increase, in diameter back to the first diameter after the screen assembly.

Abstract: A chip feeding system for a continuous digester provides for a greater rate of delivery of chip slurry to the digester, and is much less expensive than conventional chip feeding systems, typically being only 40-50% of the height of the conventional system. An atmospheric vessel may be connected at the bottom thereof to a slurry pump which pumps the chip slurry to a conventional high pressure feeder. A recirculation loop for returning liquid from the feeder to the vessel may include an atmospheric level tank, and a liquid cooler. The vessel may have one dimensional convergence and side relief, and instead of a conventional cylindrical chip bin, the chip bin may have a hopper having two transitions with one dimensional convergence and side relief. The chip bin also may be at atmospheric pressure so that no low pressure feeder between the bin and vessel is necessary.

Abstract: A method and apparatus for bleaching high consistency pulp with a gaseous bleaching reagent. The pulp is shredded and then fluffed in the presence of a contacting gas which includes the gaseous bleaching reagent within an upstream vessel comprising a pin/foil contactor so as to suspend the pulp in the contacting gas and react the bleaching reagent with the pulp. The pulp is retained in the contactor for a predetermined time which is sufficient to consume about 75% to about 90% of a selected dose of the gaseous bleaching reagent which is required to delignify the high consistency pulp from an initial Kappa number to an intermediate Kappa number. The pulp and contacting gas are then separately supplied to a porous bed reactor where the reaction of the selected dose of the gaseous bleaching reagent with the pulp is substantially completed so as to further delignify the high is consistency pulp from the intermediate Kappa number to a final Kappa number.

Abstract: Apparatus for adjusting the axial position of a rotatable feeder (2) in a charger for sluicing lignocellulose material and, if appropriate, liquid from a first space, with a first pressure, to a second space, with a different pressure, which apparatus (10) comprises an adjustment housing (11) connected immovably to the charger housing and an adjustment shaft (16) which moves the feeder in an axial direction. A worm wheel (23) is arranged on the adjustment shaft, and is coaxial with respect to the same, a shaft for a worm (27) extends through the adjustment housing wall, the worm (27) itself is in engagement with the worm wheel, turning members (29) are arranged to turn the worm and the worm wheel, conversion mechanisms (25, 26) are arranged for converting the rotational movement of the worm wheel, into an axial movement of the adjustment shaft and thus the feeder.

Abstract: An apparatus for delignifying and bleaching a lignocellulosic pulp without the use of elemental chlorine. The bleaching reactor is a horizontal vessel having a central rotatable shaft which preferably contains paddles, cut and folded screw flights or a ribbon flight, to disperse and advance the pulp particles in a plug flow manner while contacting and mixing the pulp particles with a gaseous bleaching agent such as ozone for substantially uniform bleaching thereof.

Abstract: Pumping of medium consistency cellulose pulp is effected from stand pipes or like small sized pulp vessels to which pulp is normally discharged from storage towers, treatment towers, washers, filters, presses, thickeners, or the like, particularly pumping of high temperature pulps from said stand pipes. A pump inlet is attached to a discharge opening of a stand pipe, pressurizing cellulose pulp in said stand pipe by closing the stand pipe off from the atmosphere, maintaining a superatmospheric pressure in the stand pipe, allowing the cellulose pulp to flow into the pump through the pump inlet, and pumping the cellulose pulp further using the pump.

Abstract: A method and apparatus for improving a batch cooking process, e.g. providing about 7% increase in discharge time, are provided. The invention is especially suitable for improving modern displacement batch cooking processes. A dedicated pump is mounted directly to each digester and discharges to a common superatmospheric pressure discharge tank.

Abstract: A number of distinct parallel digesters are fed with chips from a common steaming vessel. After steaming the chips are slurried and pressurized, and substantially simultaneously the steamed, slurried, and pressurized chips are transferred to at least some of (and typically each of) the distinct parallel digesters. A material stream is split into a number of individually controllable material streams (one for each of the digesters) either at the discharge from the steaming vessel, after slurrying (or at the discharge from a slurrying vessel), or after pressurizing (e.g. in a high pressure transfer device). For example a multi-branch conduit may be connected to the slurry outlet from the high pressure transfer device, the conduit having a branch directly connected to each of the digesters. A distinct return conduit may also be provided from each of the digesters to the high pressure transfer device, each return conduit preferably has a distinct flow control device and/or pump which are individually controlled.

Abstract: A pulp mill includes a digester which contains a raw material, a digesting medium, and a source of steam. Oxygen is injected into the steam line, at a point which minimizes exposure of the oxygen to the steam outside of the digester. The oxygen can also be injected directly into the digester. The oxygen speeds the chemical reactions in the digester, allowing the digesting process to be completed with a reduced quantity of chemicals and/or steam, and at a faster rate. The present invention improves the quality of the effluents from a pulp mill, and makes it easier for the operator of the mill to comply with environmental regulations.

Abstract: A process and apparatus for treating and particularly bleaching pulp contacts a pulp with a gaseous reaction medium in a reactor tower. The pulp is fluffed and refined before being added to the pulp bed and then homogeneously permeated with the gaseous reaction medium to produce a uniformly treated pulp. A distribution device is included in the reactor to uniformly distribute the pulp in the reactor and form a homogenous pulp bed having a substantially even upper surface and uniform bed depth.

Abstract: Untreated wood chips are fed to treatment, e.g. steaming at substantially atmospheric pressure, using a mechanical conveyor. Steaming may be accomplished utilizing a vertical chip bin with one dimensional convergence and side relief fed by a horizontal conveyor (e.g. screw conveyor) having a physical restriction which insures formation of a chip plug to prevent leakage of gas through the conveyor housing inlet. The physical restriction may be a generally vertical hinged plate, with an opening containing elastomeric material through which the shaft of the conveyor may pass, or a stationary generally vertical plate with one or more openings, which openings also may be covered with yielding flexible material and with the degree of sealing provided controlled by the speed of rotation of the conveyor shaft.

Abstract: The reactor comprises a pressurized vessel having an outlet member at its top and further including a blow line. The outlet member includes a housing that is in fluid communication with the vessel and to which the blow line is connected. A rotor is arranged in the housing for urging pulp in a direction of an inner side of the housing so that the pulp is discharged to the blow line while gas accumulates in the center of the housing. An outlet line is in fluid communication with an outlet channel for removing the gas from the center of the housing.

Abstract: A system and method for feeding comminuted cellulosic fibrous material such as wood chips to the top of a treatment vessel such as a continuous digester provide enhanced simplicity, operability, and maintainability by eliminating the high pressure transfer device conventionally used in the prior art. Instead of a high pressure transfer device the steamed and slurried chips are pressurized using one or more slurry pumps located at least thirty feet below the top of the treatment vessel and for pressurizing the slurry to a pressure of at least about 10 bar gauge. A return line from the top of the digester may, but need not necessarily, be operatively connected to the one or more pumps and if connected to the pumps the pressure in the return line may be reduced utilizing a pressure reduction valve and/or a flash tank. Steam from the flash tank may be used in steaming the chips.

Abstract: System for feeding a suspension, preferably a suspension of chips in a liquid carrier, to a pressurized vessel in a cellulose pulp mill, which system comprises at least one pump (25, 26) between a low-pressure part and the pressurized vessel for driving the suspension from the low-pressure part into the vessel, which pump is of the type which comprises a number of parallel discs (40, 42) which are held together to form a stack (39) and rotate in a pump chamber (36) in a pump housing about a common axis of rotation, with the spaces (46) between the discs being greater than the particles in the suspension, and with an axial inlet and a tangential outlet for the suspension. The invention also includes a pump and an apparatus unit which are intended to form part of the system.

Abstract: The present invention relates to a scraper device, preferably a bottom scraper arranged at the bottom of a continuous digester for pulp production, which scraper comprises at least one scraper arm (12), preferably arranged with shovel members (13), a shaft (6) and drive device (15) for driving the scraper arm (12), an axially extending bore (8) inside the shaft (6) for supplying liquid, and a sealing arrangement (3, 4, 5, 14) for sealing between the atmosphere and the medium in which the scraper arm (12) is intended to rotate, the bore (8) extending along only a limited part of the shaft (6) at that end of the shaft (6) on which the scraper arm (12) is arranged.

Abstract: Low temperature steaming and slurrying of wood chips results in significant improvement in treatment, the chips being maintained at a temperature below 110.degree. C. (more desirably at about 105.degree. C. or less, and most desirably at about 100.degree. C. or less) until actually heated to cooking temperature. Steaming may be accomplished utilizing a vertical chip bin with one dimensional convergence and side relief or a horizontal steaming vessel, the steaming device connected to a high pressure feeder. A pump having an NPSHR less than the NPSHA may be used for drawing slurry into the high pressure feeder from the steaming device, or a pump may be disposed between the steaming device and the high pressure feeder for forcing slurry into the high pressure feeder through a conduit including a radiused elbow. The steaming is practiced at a pressure of 5 psig or less, preferably substantially atmospheric steaming is practiced.

Abstract: Cellulose pulp is discharged from the dilution zone of a high consistency pulp tower at a substantially even volume flow and a substantially steady pulp consistency by mounting a particular parting member within a bottom portion of the tower. The parting member is constructed so as to define a first cross-sectional area between it and the tower side wall which is smaller than a second cross-sectional area below the parting member, in the dilution zone. The parting member may comprise a cone, cone frustum, pyramid, or pyramid frustum mounted substantially concentrically with the tower axis. The first cross-sectional area is at most 95% of a second cross-sectional flow area in the dilution zone, and typically about 90% or less. A ring may extend inwardly from the side wall at the parting member and define the first cross-sectional flow area with the parting member. Alternatively the parting member may itself comprise a ring having a substantially triangular (e.g.

Abstract: A chip feeding system for a continuous digester provides for a greater rate of delivery of chip slurry to the digester, and is much less expensive than conventional chip feeding systems, typically being only 40-50% of the height of the conventional system. An atmospheric vessel may be connected at the bottom thereof to a slurry pump which pumps the chip slurry to a conventional high pressure feeder. A recirculation loop for returning liquid from the feeder to the vessel may include an atmospheric level tank, and a liquid cooler. The vessel may have one dimensional convergence and side relief, and instead of a conventional cylindrical chip bin, the chip bin may have a hopper having two transitions with one dimensional convergence and side relief. The chip bin also may be at atmospheric pressure so that no low pressure feeder between the bin and vessel is necessary.

Abstract: The present invention relates to an arrangement for spreading paper pulp in a container for storing or treating the pulp, which arrangement comprises an inlet for supplying the pulp to a rotatably mounted spreader wheel and a driving member for driving said spreader wheel. The spreader wheel is provided with spreader blades, where each spreader blade has a surface which is directed towards the direction of rotation and is shaped to transport and spread the pulp outwards towards the periphery of the container during rotation of the spreader wheel. A spreader shield is arranged to divert a part of the outwardly directed pulp towards the center of the container so that the pulp is essentially spread over the entire cross-sectional area of the container.

Abstract: The invention relates to a method and a device for feeding out fiber pulp over an overflow rim (2) at the upper end of a cylindrical container (1), through which the pulp, which is suspended in liquid, is being fed continuously from the bottom and upwards. The distinguishing features are that the pulp is diluted at a level below the upper surface of the pulp by means of a multiplicity of diluting nozzles (15A-D), which extend downwards in the pulp and which are rotated around the vertical center line (12) of the container, and that the pulp, which has been fed upwards through the container, and the diluting liquid are mixed with each other to form an essentially homogeneous suspension with the aid of rotating scraper elements (14A-D) which extend downwards in the surface layer of the suspension and, at the same time as they are homogenizing the mixture, feed the suspension outwards towards, and finally over, the overflow rim.

Abstract: A batch digester loading method is described wherein a flow stream of steam enters the digester near the bottom thereof as a flow stream of wood chips enters through the top filler neck. Steam flow begins in the bottom portion of the digester at an initial, reduced flow rate after a minimum chip mass is accumulated. Steam flow is thereafter increased at a rate proportional to the inflow rate of chips.

Abstract: In a continuous digester system the chip feed equipment is greatly simplified by substituting a single vertical vessel for the conventional chip bin, steaming vessel and chip chute. An outlet at the bottom of the single vessel is connected, through a low pressure pump, to the low pressure input of a high pressure transfer device which is connected to a digester (either directly or through an impregnation vessel). A metering device, preferably through a pressure isolation device for maintaining superatmospheric pressure in the vessel, feeds chips into the top of the vessel. A first level, of chips, is established in the vessel and a second, liquid, level below the first level is also established. Steam is supplied to a volume between the top of the vessel and the second level utilizing a conduit with an automatically controlled valve and a temperature controller for at least partially controlling the valve.