Abstract: A pump for pumping high consistency materials such as paper pulp having a consistency of about 8% or more. The pump includes a pair of rotors disposed in a pumping chamber, and a number of blades extending radially from each rotor, each blade mounted for cooperation with a circumferential portion of the other rotor in sequence during rotation of the rotors in operation. The blades are suitably constructed so that during normal pumping of high consistency material they can produce a head of about 10-170 ft., remaining rigid during normal pumping. However, the blades will flex out of engagement with tramp metal or the like when encountered thereby so that no damage to the pump components results during normal operation. A relatively large clearance can be provided between each blade and its cooperating circumferential portion of the opposite rotor. The pump is especially utilizable in pulp treatment systems between vessels adapted to have high density cellulosic pulp therebetween.

Abstract: A batch type digester for wood chips in which a stream of wood chips is delivered into the center of the top of the digester tank, while liquor is being delivered through a pair of pipes at the top of the tank. Simultaneous with the delivery of the wood chips and liquor, a steam vortex is formed in the upper part of the tank by a plurality of steam jets which are directed downwardly and tangentially and form spiral flow paths below the streams of chips and liquor. The wood chips and liquor are dispersed together and the liquor thoroughly wets the chips. The chips produce a substantially even layer as they fall to the bottom of the tank. The steam vortex maintains a negative relative pressure zone which promotes the dispersion of the stream of chips and the liquor.

Abstract: A processing system including a pressurized blow tank for receiving the high pressure discharge from a wood pulp digester and utilizing the digester steam in evaporators or other heat recovery units. The blow tank which receives the treated cellulose, cooking liquor and high pressure steam from the digester also provides some additional fiber conditioning since the cellulose remains under significant pressure and temperature during the interval before it is discharged from the blow tank. A valve is provided in the blow tank for withdrawing high pressure steam separately from the cooking liquid and treated cellulose, and the valve is operated by a controller responding to pressure sensed in the blow tank. Cold cooking liquor is pumped into the blow tank in response to temperatures measured in the blow tank and the temperature of the cold liquor itself. Alternately the flow of additional cooking liquor can be controlled in response to levels sensed in the blow tank.

Abstract: A method and apparatus for continuously hydrolizing finely comminuted cellulosic fiber material and separately extracting the acid hydrolysate therefrom. Cellulosic material is fed into an upright elongated reaction vessel near the upper or top portion thereof and heated to hydrolysis temperature. The heated fiber material then passes downward through the reaction vessel and is concurrently treated by exposure to a short liquid phase which comprises concurrent impregnation and simultaneous concurrent hydrolysis to partially hydrolize the fiber material. The material is then exposed counter-currently to a liquid phase comprising a counter-current wash with simultaneous hydrolysis of a wash liquid which has been introduced from the bottom or lower portion of the reaction vessel, the wash liquid having been preheated to full hydrolysis temperature.

Abstract: A method and apparatus for continuous oxygen bleaching of cellulosic pulp is provided utilizing first and second pressurized chambers with a number of tubes in fluid communication with both of first and second chambers. Oxygen bearing fluid is intimately mixed with digested cellulosic pulp and is continuously fed under pressure to the first chamber. Communication is selectively provided between the first and second chambers through at least one of the tubular members to allow passage of pulp from the member to the second chamber. The tubular member through which pulp flows to the second chamber is progressively changed as are the members through which passage is blocked, so that the pulp remains within each tubular member sufficient time to allow oxygen-bleaching thereof without degradation, and passes through the members without channelling. The oxygen bleached pulp is continuously discharged from the second chamber. The passage of pulp through the tubular members may either be downwardly or upwardly.

Abstract: An improved tower for gas-phase bleaching of cellulose pulp at high pulp consistency including in series a gas zone space beneath said gas zone for a column of fibrous material, a mixing zone and a dilution zone, wherein a hub body is located centrally at the bottom of the tower and provided with driving means for rotation of the shaft bearing the hub body, and the torque required for rotating the hub body is continuously measured. The rate of dilution liquid is varied inversely with variation in torque thereby maintaining substantially constant the consistency of the diluted fibrous material as withdrawn from the bottom of the tower. The height of the pulp column is measured and kept constant by controlling the withdrawal of diluted fibrous material.

Abstract: A control system and a process is disclosed for a continuous wood chip downflow digestion system. The system maintains chip level in the top of the digester and maintains a consistency in the ratio of chips to liquor in the blowline thus allowing the system to run without constant operator attention. The system comprises a means for measuring the level of chips at the top of the digester and producing a level index over a predetermined time. This level index is compared with a preset level index and an error signal produced which operates a speed control means within preset limits for a rotating scraper feeding into the blowline. There is also provided a means for measuring the feed rate of chips to the digester, and a summating means for adding a predetermined ratio setpoint for the feed rate of chips against a flow in the blowline, to an integral of the error signal above or below a preset range to produce a summated ratio.

Abstract: Cooked pulp at an elevated temperature and pressure is discharged from a plurality of batch digesters sequentially into a first blow tank. The first blow tank is maintained at a substantially constant pressure which is less than the pressure in the digester and greater than atmospheric. Pressurized steam is released from the first blow tank into a dirty steam system as pulp is discharged into a second blow tank at a substantially constant rate in a non-interrupted flow stream. The pressure in the second blow tank is maintained at about atmospheric pressure. A blow line refiner is interposed between the first and second blow tanks.

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: A chips bin that allows thorough steaming of the chips in the bin without blockage of the chip flow. A chips bin with a vibrating discharge includes an activator cone and a number of support arms extending from the activator cone to the bottom portion of the bin. A number of steam ports are formed in each of the supporting arms and steam is introduced into the supporting arms and underneath the activator cone. The steam ports are formed in sidewalls of the supporting arms, and steam is introduced both underneath the bottom portion of the cone and underneath a top portion of the cone.

Abstract: A screw conveyor which is particularly used for feeding in and compressing ligno-cellulosic material, such as wood chips, shavings, bagasse, sawdust and similar compressable material. The screw conveyor comprises a casing having a bore which tapers conically from a material inlet and to a material outlet end. A screw feeder having helical flights and an intervening spiral groove rotates within the bore to advance the material fed into the casing towards the outlet end while being progressively compressed into a plug. The casing has an opening in which stopper means move in a closed circuit to successively engage the spiral groove during the rotation of the screw feeder, thereby preventing the material from rotating and thus allowing it to be continually advanced while being progressively compressed.

Abstract: A batch type digester for wood chips in which a stream of wood chips is delivered into the center of the top of the digester tank, while liquor is being delivered through a pair of pipes at the top of the tank. Simultaneous with the delivery of the wood chips and liquor, a steam vortex is formed in the upper part of the tank by a plurality of steam jets which are directed downwardly and tangentially and form spiral flow paths below the streams of chips and liquor. The wood chips and liquor are dispersed together and the liquor thoroughly wets the chips. The chips produce a substantially even layer as they fall to the bottom of the tank. The steam vortex maintains a negative relative pressure zone which promotes the dispersion of the stream of chips and the liquor.

Abstract: An apparatus and method for the digestion of cellulosic fiber material providing pulp of very uniform quality. Cellulosic fiber material entrained in treatment liquid is fed into a top portion of a first vertical treatment vessel, impregnation of the fiber material with treatment liquid taking place in the first vessel. A first flow path of fiber material entrained in and impregnated with treatment liquid is established from the bottom of the first vessel to a top portion of a separate second vertical treatment vessel, liquid substantially filling the second vessel. Liquid is withdrawn from the top portion of the second vessel (without screening) and a second flow path is established of the liquid withdrawn from the second vessel back toward the bottom portion of the first vessel, heating of the liquid during transport in the second flow path taking place.

Abstract: A method and apparatus for presteaming of wood chips and the like. The chips are treated in a vertical presteaming vessel with steam under low pressure, and removal of the air from the chips is facilitated by maintaining the presteaming vessel substantially at or near atmospheric pressure. An exhaust fan, controlled by a pressure probe in the presteaming vessel, may be provided for maintaining the pressure in the vessel. The amount of air that can enter the vessel through the chips inlet is minimized by an inclined rotating screw assembly with a partial flight which elevates the packs and chips to form an isolation seal at the chips inlet into the vessel.

Abstract: Impregnation of fiber material before digestion is accomplished utilizing a minimum amount of equipment. Liquid with entrained fiber material -- both fiber material sufficiently impregnated with liquid to be denser than the liquid and material insufficiently impregnated to be denser than the liquid -- is fed from a high-pressure transfer valve to an inlet at the top of a continuous digester. The digester has an outlet disposed vertically above the inlet, and liquid along with fiber material of lesser density than the liquid is withdrawn from the outlet. The withdrawn liquid and fiber material is recirculated back to the transfer valve through a conduit adapted to allow the passage of fiber material entrained in liquid therethrough. Each individual portion of fiber material is continuously circulated until it becomes sufficiently impregnated with liquid to descend into the digester and form a fiber column therein.

Abstract: An improved tower for gas-phase bleaching of cellulose pulp at high pulp consistency including in series a gas zone space beneath said gas zone for a column of fibrous material, a mixing zone and a dilution zone, wherein a hub body is located centrally at the bottom of the tower and provided with driving means for rotation of the shaft bearing the hub body, and the torque required for rotating the hub body is continuously measured. The rate of dilution liquid is varied inversely with variation in torque thereby maintaining substantially constant the consistency of the diluted fibrous material as withdrawn from the bottom of the tower. The height of the pulp column is measured and kept constant by controlling the withdrawal of diluted fibrous material.

Abstract: A method and apparatus for filling a treatment vessel with a fiber material -- liquid mixture. A conventional feeder rotor, having a number of pockets extending therethrough, has each pocket thereof sequentially filled with chips-liquid mixture in a first position from a pretreatment vessel. A portion of the liquid is withdrawn from the pocket, and the pocket rotates to a second position wherein the chips-liquid mixture in the pocket is discharged into a digester by a liquid flow. The pocket then rotates to a third position wherein the liquid in the pocket is discharged by admitting a gas, such as steam, under pressure into the pocket (and the pocket simultaneously filled with gas), and then to a fourth position wherein the gas is allowed to expand and be transported to a pretreatment vessel while the pocket is filled with cooking liquor, and thereby is ready to begin another cycle.

Abstract: An apparatus and method for the displacement impregnation of cellulosic chips material with digesting liquid. Cellulosic chips material and liquid are fed from a source to a high pressure transfer valve whereat the pressure of the chips and liquid is boosted. The chips are fed from the high pressure transfer valve through a feed system to the topmost portion of a vertical treatment vessel, the vessel having a topmost portion and an impregnation zone in an upper portion thereof below the topmost portion. A countercurrent flow of digesting liquid in the vessel impregnation zone is established to impregnate the chips material with digesting liquid, and displace the water and minerals therefrom, and liquid withdrawn from the top of the treatment vessel is withdrawn into the feed system. The withdrawals insure that essentially no free water enters the impregnation zone. A chips plug is established at the vessel top through which all withdrawn liquid must pass.

Abstract: An apparatus and method for impregnating fiber material with treatment liquid before treatment thereof in a high pressure vertical fiber material treatment vessel. Fiber material and treatment liquid under relatively low pressure flow in a first flow system, continuous withdrawal of liquid from the first system taking place. A second flow system of fiber material and treatment liquid, under relatively high pressure (the second flow system including an impregnation portion of the treatment vessel), is provided. Fiber material entrained in liquid in the first system is transferred to the second system, and the pressure thereof boosted, by a pocketed-rotor transfer device.

Abstract: A static discharger includes a vertical casing connected to a pressurized pulping digester for receiving a stream of fibrous material and having a valve isolated scrap collector positioned on its lower end. A discharge neck on which a blow valve is mounted extends from the casing above the scrap collector and is covered with a grid plate having self-cleaning openings. A pipe mounted tangentially on the casing introduces flooding liquid thereto while a similar pipe may be located on the scrap collector. A sealed casing cleanout opening may be provided. No moving parts are involved since discharger agitations result from the flooding media. Heavy foreign body impurities in the stream sink to the scrap collector where they are removed without process interruption. Buoyant objects remain suspended in the liquid. Blow valve plugging is eliminated. For higher fiber consistency, a grid plate wiping agitator may be advantageously installed in the casing.

Abstract: A method and apparatus for filling a treatment vessel, such as a digestor, with fiber material and liquid. A chips-liquid mixture from a pretreatment vessel is fed through a conventional feeding valve to a treatment vessel while the chips-liquid mixture is being acted on by other means in the feeding valve. The feeding valve includes a rotor having a number of pockets extending therethrough, and a plurality of inlets and outlets arranged around the periphery of the valve for communication with the pockets thereof. In a first position of the valve chips-liquid mixture is fed into a pocket, and a portion of the liquid is strained off, then the valve rotates to a second position wherein a quantity of the liquid is displaced by gas or steam while the chips are maintained in the pocket, and then the valve rotates to a third position wherein the chips in the pocket are discharged into the treatment vessel.

Abstract: A method for continuous treatment of fiber material in a digestor or the like that allows substantial segregation of the digestor treatment zones so as to prevent upflow of liquid from a bottom zone to an upper zone. An area of reduced cross-sectional area is provided between each treatment zone which increases the velocity of flow of fiber material and entrained liquid in that area, and substantially prevents upward movement of liquid therepast.

Abstract: An improvement in continuously feeding slurry material to vertical upflow treatment towers. The improvement comprises providing a plurality of spaced apart inlet or outlet openings in the bottom inlet end of the tower and opening and closing the openings in timed sequence to allow the material to selectively flow into the tower from different spaced locations but continuously at a substantially constant rate.

Abstract: Gaseous reaction apparatus wherein a portion of the supplied gas is discharged from the reaction vessel at a location below the upper level of a therein contained columnar mass of material wherein the gas is discharged into a receiving chamber extending along the outer periphery of the vessel and open to the lower portion of the vessel through an unrestricted opening being free from screens and filters, and such discharged portion of the gas, with or without cooling, is recirculated back into the upper inlet end of the vessel, thereby controlling the temperature in the vessel by removing or redistributing heat therein. Such apparatus is particularly useful in the gas phase treatment of fibrous material such as the bleaching or delignification of lignin-containing cellulose pulp.

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.