Abstract: In a papermaking machine, a method and mechanism for delivering stock to a dewatering web including a pressure headbox with a narrowing slice opening, a receiving throat either with a single traveling forming wire or a pair of traveling forming wires, bridging the space between the headbox opening and the wire so that the stock jet is contained without a free surface, and applying a trailing flexible element opposite the stock in a single wire machine or against one wire in a twin wire machine with the force and location of the trailing element controlled by a series of push rods arranged parallel in a cross machine direction.

Abstract: The present invention relates to a method of reducing the content of halogenated organic compounds in the spent bleach liquor from the bleaching of lignocellulose-containing material with compounds containing halogen, wherein the spent bleach liquor, in a stage where no essential delignification or bleaching of the pulp takes place, is maintained at a pH of from 2.5 up to about 10, and wherein the residence time and the temperature are selected such that the amount of dissolved halogenated organic substances in the spent bleach liquor is reduced by at least 30%.

Abstract: The specification discloses a method for the treatment of black liquor from a kraft or soda pulping process which comprises forcibly conveying the black liquor through an elongate conduit containing at least one vent at a position along its length while subjecting the black liquor to a working action and maintaining the temperature of the black liquor at least about 80.degree. C. so that the black liquor is compressed and mixed as it is conveyed through the conduit to promote the separation of liquid components from the black liquor into the vent by expression and vaporization. As a result, the solids concentration of the material may be increased to provide an improved quality fuel for soda recovery boilers. The process is advantageously carried out using a vented screw extruder which is equipped to supply heat to the black liquor from the screw interiors and barrel housing to promote vaporization of volatiles and to maintain the flowability of the material as it is conveyed through the extruder.

Abstract: A twin-wire former for making a web of paper (9) having two endless loop travelling screens (11, 12) which travel over respective breast rolls (13, 14) and form a wedge-shaped feed gap of a twin-wire region. In the twin wire region the two travelling screens pass first over a curved stationary supporting device (15), then over a forming roll (16) which lies in the same screen loop (11) as the curved supporting device (15), and finally over a screen suction roll (18) which lies in the other screen loop (18). In order to form a large storage volume for water, an additional lattice-like outer shell (27) surrounded by a coarse-mesh textile filter envelope (28) is arranged on the body (16a) of the forming roll. Approximately half the periphery of the screen suction roll (18) is wrapped by the two screens (11, 12). At the end of the said wrapping zone, the one screen (11) runs off from the screen suction roll (18) followed by the other screen (12) together with the web of paper (9).

Abstract: A method of drying black liquor to a dry solids content of about 100% in which water is evaporated from the black liquor by direct heat exchange contact with hot smelt from a recovery furnace in which the dried black liquor is burned.

Abstract: The uniformity of layered paper sheets produced using a layered headbox can be improved by confining the outer layers between parallel surfaces within the headbox immediately prior to leaving the headbox.

Abstract: A process is provided for the treatment of an acidic aqueous effluent derived from a chlorine or chlorine compound bleaching process. The acidic effluent is reacted with a neutralizing base selected from carbonates, hydroxides and oxides of Al, Cr, Co, Fe, Mg, Mn, and Ni. The neutralized effluent is concentrated and residual base and HCl are subsequently recovered. The concentration of neutralized effluent may be accomplished by passing the neutralized effluent through the cooling tower of the pulp mill.

Abstract: A process for removal of adsorbable organic chlorine (AOX) in which the acid-soluble AOX present in kraft chlorination (C.sub.D) effluents are destablized and converted to inorganic chloride by pH shift using the alkalinity and acidity sources available at the mill; C.sub.D effluent, typically having a pH of 1-2 and E.sub.1 effluent, typically having a pH of 9-12 can be mixed in various proportions to achieve a pH between 6.5-9.0 or the C.sub.D effluent is adjusted in pH to 6-11 with an alkaline composition so taht alkaline hydrolysis as well as precipitation of organic material occurs and the treated effluent contains less AOX than present in the original untreated effluents; the AOX removal is enhanced substantially by (i) the presence of a sulphide or (ii) by carrying out the alkaline treatment at elevated temperature and pressure.

Abstract: An extended drainage strip (3) is placed next to the primary sieve (5) of a double-sieve mold. It has a liquid-intake space (2), which is disposed between the part of the surface (4) facing the sieve and the sieve (5). Disposed next to the other sieve (6) is at least one adjustable strip (7) arranged so that it can be placed opposite the intake space (2). Intake space (2) has a cross-sectional size that increases, if necessary, in the direction in which the liquid flows. By pressing the adjustable strip (7) against the intake space (2) of the extended strip (3), the shape of the intake space (2) can be controlled, and the suction or intake of the liquid in the intake space (2) is regulated. One object is to achieve steadily increasing suction in the flow direction. This result assists in preventing undesired pressure surges. The drainage device is simplified and thus easy to monitor. Drainage proceeds carefully, with higher retention of fine particles in the sheet of material between the sieves.

Abstract: The invention relates to apparatus for the dewatering of a web of cellulosic matter or a web of material for the pasteboard or cardboard production, having endless screen belts or the like circulating in opposite directions between which the web is made to pass for dewatering, the web being made to pass through at least one first dewatering zone with at least two screen belts or the like and thereupon to at least one further dewatering zone, in particular a compresion zone, with at least two screen belts.

Abstract: A mechanism and method for initially dewatering a paper stock slurry between looped traveling forming wires wherein the wires pass over turning bars, controlling the cross machine curvature of the turning bars to compensate for variations in curvature due to temperature effects on the turning bar and to control the cross machine curvature of the turning bar to a predetermined fixed shape for wide machines to control the travel of the wire over the bars by applying bending moments to a support beam for the turning bar such as by providing separate liquid chambers in the beam and directing heated or cooled water into the chambers to bend the bar to either a positive crown, to be straight or to a negative crown.

Abstract: An improved kraft pulping process is characterized by the addition of a spent concentrated sulphuric acid composition containing organic matter to a kraft recovery system to provide a mixture enriched in its total sulphur content that is subjected to dehydration, pyrolysis and reduction in a recovery furnace. The organic matter of the sulphuric acid composition is particularly beneficial as a source of thermal energy that enables high heat levels to be easily maintained to facilitate the oxidation and reduction reactions that take place in the furnace, thus resulting in the formation of sulphide used for the preparation of cooking liquor suitable for pulping.

Abstract: The present invention relates to an apparatus for forming fibrous paper or board web on a double wire section of a paper machine. The double wire section includes a first wire loop and a second wire loop. In a first dewatering zone of the double wire section where the paths of both wire loops are substantially linear, the web direction is adjustably deviated towards the second wire loop. In a second dewatering zone located after the first dewatering zone, the web is curved towards the first wire loop to form a curved dewatering zone. In the linear dewatering zone, the second wire loop is loaded towards the first wire loop with wire support members. In the curved dewatering zone, the compression between the wires is effected by adjustably tightening the wires.

Abstract: A gap former in a paper machine, comprising a lower wire loop (10) and an upper wire loop (20), which together define a substantially horizontal twin wire forming zone, which comprises the following web forming zones (a), (b) and (c): (a) In the area of the forming gap (G), a first suction zone (11a) placed inside the first forming roll (11), and immediately thereafter a second suction zone (11b) is placed in forming roll (11). The suction zones (11a, 11b) are placed in the first upper quarter of the first forming roll (11) at the side of the forming gap (G). The levels of negative pressure (P.sub.1, P.sub.2) in the suction zones are adjustable. (b) A forming shoe (12), which is provided with an open guide deck (26), the interior space in the shoe being divided into at least two subsequent suction chambers (12a, 12b, 12c), the levels of negative pressure (P.sub.a, P.sub.b, P.sub.c) effective in said suction chambers being arranged to be adjustable, preferably separately adjustable.

Abstract: The invention relates to the reception of fibers under fibering machines to obtain a mat of mineral wool. It proposes assigning to each fibering machine its own collecting zone, the surfaces of the collecting zones increasing in the direction of the increase of base weight. The invention also proposes a device characterized by the presence of two reception drums for three fibering machines.

Abstract: The ledge is arranged transverse to the machine direction in a substantially flexure resistant manner and is adjustable for guiding the wires between which a web of material is formed. The ledge contains a guide surface which faces the wires and has a special contour. For improved control of the pressure changes occurring in the region of the ledge, the ledge contains a supporting member and a pressing member which contains the guide surface. A pressing device is supported at the supporting member and the pressing member can be adjusted in a direction relative to the wires as well as relative to the supporting member by using the pressing device for simultaneously elevating the pressing member and inclining the pressing member with respect to the machine direction. Advantageously the pressing device constitutes a hose which is subjected to a pressurizing medium and thereby deformable.

Abstract: A double screen former for the manufacture of a paper web has two continuous screens forming together a double screen zone. The one screen runs in the double screen zone across rigid laths that are arranged on the dewatering box at a mutual spacing. Additionally, the other screen runs in the double screen zone across several laths which are supported by means of flexible elements and can be forced on the screen at a selective force. The space between the flexibly supported laths is at least approximately twice as large as the space between the rigid laths.

Abstract: A method is disclosed for forming a paper web having a low tensile ratio. The method includes the steps of ejecting stock substantially horizontally from a headbox, and receiving the rejected stock onto a substantially horizontally disposed looped first wire, moving at substantially the same speed and the same direction as the ejected stock. The arrangement is such that a first portion of water is removed from the ejected stock downwardly through the first wire during passage of the ejected stock through an initial dewatering zone. The partially dewatered stock is sandwiched between the first wire and a looped second wire, the wires defining therebetween a secondary dewatering zone for further dewatering the ejected stock. A second and third portion of water are removed downwardly and upwardly, respectively, through the first and second wires during movement of the ejected stock past a curved shoe.

Abstract: The invention concerns a method for the treatment of the spent liquors obtained from pulp production processes in the wood-processing industry, in which method the waste obtained from a chemical cooking process and that obtained from a mechanical process are merged for joint treatment. The chemical process may be e.g. a sulphate process and the mechanical process e.g. a chemi-thermomechanical process (CTMP), and the invention presupposes that the facilities for these processes are located close by each other, suitably within the same industrial complex. The essential feature of the invention is that the spent liquor of the CTMP is used as wash water in counter-current washing of the pulp obtained from the chemical process.

Abstract: A twin-wire former for the production of a web of paper from a fiber suspension. An upper endless loop of wire belt having a lower horizontal run and a lower endless loop wire belt having an upper horizontal run. Guide rolls support the wire belts to define a twin-wire zone. The upstream inlet wedge of the twin-wire zone is disposed at the outlet from a head box. The initial part of the path of the twin-wire zone has a gradual curvature convexly with respect to the lower wire belt, and in that initial portion are positioned guide tables, suction boxes and dewatering elements. This curved initial part is followed by a forming roll within the loop of the upper wire belt. The twin-wires wrap an arcuate sector of the lower region of the forming roll. A support roll follows the forming roll. The support roll is upraised sufficiently to wrap the twin-wires around the bottom of the forming roll and over an arcuate sector at the top of the support roll.

Abstract: A paper web forming apparatus essentially comprising two wires which move together with stock which is held therebetween and a plurality of wire supporting members for supporting the wires, each of the wire supporting members forming a wedge-shaped space as defined between the wire surface and the wire supporting member, wherein the wedge-shaped space is so designed that the width as measured therebetween decreases as seen in the direction of movement of the wires.

Abstract: The present invention relates to an apparatus for guiding the wires of a paper machine former. The former includes a double wire section including two wires (1,2) in parallel direction (R) in which on the other side of the wires (1,2) a dewatering unit (10) is arranged to drain water from the stock (3) flowing between the wires and in which at least the farthest wire (2) from the dewatering unit is compressed with foil lists (20) or equivalent support members against the wire (1) nearest to the dewatering unit (10) in cross-machine direction with respect to wire direction (R) and across the web width. The load of these foil lists (20) is achieved by separate pressurized load hose construction (21) arranged between each foil list (20) and support table or equivalent in order to achieve the desired press to the stock (3) between the wires (1,2).

Abstract: This invention relates to the production of dry black liquor solids and more particularly to a process and apparatus for producing such solids having a moisture content below five percent water by weight. The process includes supplying a first stream of black liquor having a solids content in a range such that the first stream flows as a viscous liquid, supplying a second stream of black liquor solids having a solids content in a range such that the second stream flows as a friable granular dry solid, and mixing the first and second streams of black liquor solids and producing an output stream having a solids content such that the output stream flows as a dry solid.

Abstract: The invention relates to a process for the preparation of an essentially sulfide-free alkali liquor starting from a pulp mill alkali sulfide source, characterized by reacting in alkaline medium the alkali sulfice source with copper (II) oxide and/or copper (I) oxide, optionally with the addition of water, in a mole ratio oxide to sulfide (calculated as alkali sulfide) (charging) of at least 0.9 and allowing the mixture obtained to react at a temperature of from 30.degree. to 130.degree.0 C. to form hydroxide in an amount equivalent to the amount of sulfide and to precipitate a solid phase consisting essentially of copper (I) sulfide, copper (II) sulfide or a mixture thereof, whereupon the solid phase is separated in a way known per se to obtain an essentially sulfide-free alkali liquor, the reaction time of the precipitation reaction being adjusted with regard to the charging and temperature selected so that the residual concentration of copper ions in the final alkali liquor is below 1 mmole/l.

Abstract: A method of and an arrangement for leading a web on to a desired wire in a paper machine or the like. When the web moves between two wires, it is transferred on to one wire after the wires have moved in parallel over a distance with the web therebetween making contact with both wires. The transfer takes place when the wires start to move in different directions by sucking the web on to one of the wires by a vacuum acting through said wire. For improving the detachment of the web from the other wire, the direction of travel of the wire is changed abruptly at the parting point of the wires by leading it along a suction box comprising a cover piece formed by cleats and arranged to form an angle in such a way that the point of the angle projects towards the wire. When the wire moves along the cleats of the cover piece of the suction box, its direction of travel is abruptly changed at the point line of the angle, whereby the web is detached from the other wire completely in a moment.

Abstract: The invention relates to a wet end section of a twin wire paper machine. Each wire forms a wire loop. The wires are led together along a vertical, rising, common path, which starts at a wedge shaped feed nip at the bottom of the common path. The nip is formed by the two wires and is defined by a forming cylinder arranged in the loop of the inner wire. Inside the other outer wire, there is a fixed curved surface or outer surface having a center of curvature which lies on one side of the rising common wire path. A further curved inner surface which follows the outer surface along the wire path is provided on a doctor blade carrier or pivotable crossbeam located inside the loop of the inner wire. This is followed by a suction roll arranged in the loop of the outer wire. The length of the further inner surface is shorter than the length of the outer surface.

Abstract: A method of cleaning green liquor of solid particulate impurities by adding caustic lime corresponding to 0.5 to 10% of the amount of caustic lime needed for complete causticizing of the green liquor to the green liquor in a soda dissolving tank or in a separate mixing tank to which the liquor is led directly from the dissolving tank. Calcium carbonate precipitates and forms, with the impurities, particles having better settling and filtration properties than particles in green liquor which has not been treated with caustic lime.

Abstract: In a causticizing process for separating at least white liquor and lime sludge out of the process, filters in the form of discs or drums are arranged. The filtrations take place under positive pressure and the filters are arranged in a closed system. Such a pressure filter can also be arranged for the separation of sludge.

Abstract: A twin-wire former for a paper machine having a lower wire and an upper wire. The former has a twin-wire forming zone which has forming members and forming zones situated in a specific sequence as follows. A downwardly curved forming zone is confined to a sector of a large-diameter forming roll mounted on a frame of a lower wire unit, the magnitude of this sector being within the range of <90.degree.. A second forming roll then follows which is preferably provided with a hollow face and onto which the wires arrive from the first forming roll. The twin-wire forming zone is curved within a certain sector of less than 90.degree. on the second forming roll so as to become horizontal. A forming shoe is provided with a ribbed deck and fitted after the second forming roll inside the lower wire loop, this forming shoe having a relatively large curve radius after which the twin-wire forming zone ends and the web is arranged to follow along with the lower wire.

Abstract: A joint dewatering zone of wires for dewatering a web to be formed in a two-wire papermachine having a first wire loop and a second wire loop, includes a first forming roll which is situated inside the second wire loop and other dewatering means which are situated after the first forming roll inside the first wire loop. The other dewatering means comprises as a combination a first suction box, a second suction box with a curved guiding surface, and a roll interposed between the suction boxes.

Abstract: A web former for a paper machine having a lower-wire loop which forms an initial single-wire part of a dewatering zone. The former also includes a top-wire unit which includes an upper wire which forms a twin-wire dewatering zone together with the lower wire. The former also includes a first forming roll in a direction of web travel that is provided with an open hollow face and is fitted inside the upper-wire loop. The twin-wire forming zone begins in conjunction with the first forming roll. There is a forming shoe inside the lower-wire loop which is provided with a curved deck that guides the lower-wire loop. The former includes a second forming roll fitted inside the upper wire loop and situated after the forming shoe. A device for collecting water is provided in the former and operates without any external suction source, with dewatering being based upon kinetic energy of water that is being removed and/or upon gravity.

Abstract: Hybrid former for a paper machine which has a lower-wire loop forming a single-wire dewatering zone in which water is removed from a web being formed by a dewatering member situated inside the wire loop through the lower wire. The former also has an upper-wire unit which includes an upper-wire loop forming a second twin-wire dewatering zone after the first single-wire dewatering zone, together with a run of the lower wire. The former additionally includes a hollow-faced first forming roll fitted inside the upper-wire loop, at which the second, twin-wire dewatering zone starts, this zone being curved upwardly over a certain sector of this forming roll. A forming shoe is fitted inside the lower-wire loop after the forming roll and guides the second dewatering zone. This forming shoe is provided with a curved deck for guiding the lower-wire loop.

Abstract: The present invention relates to a method of recovering chemicals from spent liquors while at the same time utilizing energy liberated during the process. The spent liquors are gasified and partially disintegrated in a reactor (1), external thermal energy independent of combustion being simultaneously supplied to the reaction zone (2) of the reactor, after which the resultant melt is separated (at 9) at substantially the temperature prevailing at combustion, the gaseous product thereby formed being quenched in a quenching and cooling zone (6), to a temperature below 950.degree. C. A product gas is thus obtained which contains substantially no sulphur impurities, an alkali product with high sulphide content and an alkali product substantially free from sulphide and having low Na.sub.2 CO.sub.3 content.

Abstract: A method and apparatus are disclosed for concentrating an alkaline waste liquor containing sulfur compounds, the so-called black liquor, which is discharged from a step of Kraft-cooking wood fibers, in order to recover the cooking chemicals from said waste liquor, characterized in that CO.sub.2 gas and/or a gas containing CO.sub.2 gas is added to said waste liquor as a boiling-point-lowering agent, viscosity-lowering agent and solidification promoter, after a step of oxidizing said waste liquor and in or prior to one or more stages during the step of concentrating said waste liquor. Also disclosed is an apparatus for concentrating an alkaline waste liquor containing substantially no sulfur compounds (i.e.

Abstract: This device, preferably formed as a dual paper machine, has according to a preferred embodiment two endless screens, mainly a lower screen (21) and an upper screen (22). The lower screen (21), on which is formed a paper web, and the upper screen (22) are moved together in the lower part of a dehydration cylinder (25) arranged in the upper screen. Both screens (21,22) are unrolled from the rising lower quadrant of said cylinder (25) and are laid on the upper part of the support cylinder (26) arranged in the lower screen (21). The bandage of the dehydration cylinder (25) has hollows which absorb water from the screens along their arcs of contact with the cylinder and which project the water towards the inside of the loop formed by the screens of the cylinder. In the feed direction of the screens and downstream of the support cylinder (26), there is arranged a receiving container (36) for the projected water.

Abstract: A method to simultaneously de-water and form a sheet of pulp is disclosed. The method employs a pair of wire meshes, the meshes being adapted to move continuously under tension and to receive pulp continuously from a stock inflow tank. A layer of pulp is subjected simultaneously to progressive mechanical compression and to aspiration of the water at a constant value owing to a siphon effect. Also disclosed is an apparatus to carry out this method.

Abstract: A forming apparatus (10) is disclosed for forming a web from stock. The apparatus (10) includes a frame (14) and a first and second plurality of guide rolls (16-26 and 30-34) rotatably connected to the frame (14). A first and second forming wire (28,36) extend respectively around the first and second plurality of guide rolls, with the first and second wires (28,36) cooperating together to define therebetween, a forming section (38) having a first and second (40,42) end. A headbox (12) is disposed adjacent to the first end (40) of the forming section (38). A suction shoe (44) is disposed adjacent to the first end (40) of the forming section for effecting an initial dewatering of the web. The suction shoe (44) has a curved surface (46) which abuts against the first wire (28) for removing a first portion of the water through the first wire (28) and a second portion of the water through the second wire ( 36).

Abstract: The invention relates to a method of regulating, for the purpose of burning soda-ash in a recovery boiler furnace, the feeding-in or combustion conditions of concentrated spent liquors of varying chemical and physical properties by measuring some physical property of a liquor fed into the recovery boiler furnace and by regulating the feeding-in and combustion conditions directly on the basis of the thus measured physical properties. According to the invention, the maximum swelling, upon heating, of a dry-matter particle of the liquor fed into the recovery boiler furnace is measured. On the basis of this measurement the temperature, pH value, or injection pressure of the liquor fed into the furnace, or the height of the injection point or the direction of injection, or the feeding of air into the furnace is adjusted directly on the basis of the maximum swelling measurement.

Abstract: The invention relates to a filter belt press for separating solid matter from material suspensions, in particular fibrous material suspensions, in which the filter belts are guided through a wedge-shaped dehydrating zone in which the filter belts are supported at least over portions by wedge-like converging filter plates. For an optimation of the pressing effect, it is provided that the filter belts (3,4) be guided from this first dehydrating zone (1), in which the filter plates (5) are optionally supported by dehydrating boxes (6) or provided with dehydrating boxes (6) on their outsides, into a surface press (2) or surface pressure means for the material (29) or filter cake present between the filter belts (3,4), the press (2) in particular being immediately adjacent the end of the wedge-shaped dehydrating zone (1).

Abstract: In a method for burning evaporated waste liquor obtained at pulp production in accordance with cooking processes on sodium basis for recovering sodium carbonate and sulphide, the liquor (10) is injected towards the inlet end side (4) of a cylinder-shaped reaction chamber with mainly tangential gas supply (6). In this cyclone (2) the liquor is dried and pyrolysed by hot fumes recirculated from the outlet portion (12) and obtained through the ejector action of the liquor injection. After ignition of the pyrolysis gas and rests of the liquor the formed smelt (16) is discharged after sulphuration from the outlet portion of the cyclone. The fumes of the cyclone are oxidized in a separate furnace (14) after the cyclone (2). A stable and, from a process technical point of view, suitable combustion without support firing with any other fuel can be maintained with liquor including 25-40 % of water.

Abstract: An apparatus is disclosed for making a paper web from stock. The apparatus includes a first and a second forming wire which cooperate together to define therebetween a web-forming section having a first and a second end. A headbox is disposed adjacent to the first end of the forming section for ejecting the stock between the wires such that the web is formed from the stock during passage of the stock from the first towards the second end of the forming section. A first felt is disposed downstream relative to the forming section with the first felt running contiguously relative to the second wire such that the second wire is disposed between the first felt and the web. A second felt is disposed downstream relative to the forming section and on the opposite side of the web relative to the first felt.

Abstract: All of the essential operating parts for adding a top former assembly to a new Fourdrinier paper machine or for converting an existing Fourdrinier paper machine into a top former are carried by a supplemental frame assembly which can be mounted on the main Fourdrinier frame with minimal modification of the latter except the addition of simple parts for securing the supplemental frame assembly on top of the main frame. The primary operating parts of the top wire assembly are a hollow foraminous roll and a top wire deflector which cooperate to collect and deliver liquid expressed through the top wire into a receptacle that is carried by the supplemental frame assembly, and special provision is made for utilizing the top wire deflector to correct for irregularities in the cross machine profile of the paper sheet as it is being formed. Provision is also made for operating the resulting top former in roll former mode, blade former mode, or a combination roll and blade former modes.

Abstract: Eenrgy and process chemicals are recovered from spent liquor in pulp preparation by thermally decomposing the spent liquor to solid and gaseous products at an elevated pressure and with addition of oxygen. The supply of oxygen should be less than that stoichiometrically required for a complete combustion and the temperature at the decomposition should be below the temperature at which a melt is formed.After recovery of sulfur-containing compounds the gas formed can give off energy in a gas turbine, thereafter generate steam and finally be used for drying fuel which is subsequently gasified under pressure and provides a further contribution of energy in the form of a combustible gas.Process chemicals are recovered from the solid products in known manner.

Abstract: Process for controlling, or reducing, the level of oxidized anions, usually oxidized sulfur compounds or oxidized nitrogen compounds, in a reaction medium, preferably in a closed loop recirculating system. The process comprises withdrawing a purge stream from the reaction medium and reducing the oxidized anions in a reduction furnance 44 having a char bed 48. The reduced compounds are recovered from the reduction furnace as smelt 50. Where the reduced compounds are useful in the reaction medium from which the purge stream was withdrawn, the reduced compounds are preferably returned to the reaction medium for further use therein.

Abstract: A multi-ply paper web forming apparatus utilizes first and second forming wires which travel in a co-running path for a portion of their length and which form a throat into which an aqueous slurry of paper pulp fibers is introduced. The slurry is dewatered between the co-running first and second forming wires upwardly and downwardly to quickly produce a substantially formed, but still moist, top ply web which is carried on the second forming wire onto a base ply web which has previously been formed on the wire of a single wire former. The first surface of the top ply web is brought into ply bonding engagement with the surface of the base ply web to produce a composite multi-ply web which has superior overall ply bond, retention and dryness before leaving the web forming section of a papermaking machine.

Abstract: Process for recovering chemicals and energy from cellulose waste liquors preferably black kraft liquor obtained in a paper pulp sulphate process, comprising the following, three distinct and separate steps: In the first step the concentrated black liquor is gasified in a pressurized gasification reactor by so called flash-pyrolysis at 700.degree. to 1300.degree. C., normally 800.degree.-900.degree. C., whereby an energy rich gas is produced, and in which the inorganic chemicals of the black liquor are contained in the form of molten suspended droplets, mainly comprising sodium carbonate and sodium sulphide. In the second step the gas from the gasification reactor is rapidly cooled through direct contact with water, and with green liquor, which is formed when the molten droplets and the hydrogen sulphide are dissolved in the quench liquid. The cooled gas subsequently passes through a scrubber.

Abstract: The invention concerns a dewatering band press. The wires (2) in the press are wider than the rolls (1), and in view of sealing the edge of the pulp web (3), two rails (4) are placed outside the ends of the rolls, the wires running between the said rails, and a sealing beam (5) is placed between the rails and the wires. The solution is durable and reliable, because it has no readily worn abrading parts.

Abstract: A process for cooking and bleaching pulp in a closed system, wherein spent liquors from the cooking and the bleaching are recovered and their chemicals are regenerated and recycled as cooking and bleaching chemicals.

Abstract: A two-wire paper forming apparatus wherein the co-running forming wires converge over a forming roll and diverge over a couch roll downstream of the forming roll. A curved forming zone begins where the forming wires converge over the forming roll to receive a stock stream, and extends to before the couch roll whereby the forming roll in conjuction with a pair of convexly curved dewatering shoes disposed against the forming wires between the forming roll and the couch roll form the web while providing improved retention and formation.

Abstract: The present invention relates to a support apparatus of a dewatering unit (30) below a bottom wire of the twin wire forming section of a paper or board machine.The problem in known, corresponding arrangements has been insufficient crosswise stiffness of the dewatering unit and lack of adjustability.The above-mentioned disadvantages have been eliminated or minimized by a support arrangement, characterized in that the dewatering unit (30) is supported on beams (36) transversely in view of the machine direction by means of a hose-like pressure-medium filled elements (37), which also allow a longitudinal adjustment of the dewatering unit by means of an adjusting element (38).