Abstract: The invention relates to a process for preparation, under reducing conditions, of cooking liquors having high sulphidity for sulphate pulp cooking, wherein the black liquor obtained in the cooking process is fed, after evaporation, completely or partly to a reactor operating at increased temperature which is obtained by energy supply from an external heat source and/or release of energy from the black liquor, a melt essentially consisting of sodium sulphide being formed and withdrawn to be further processed to cooking liquor. The process of the invention is characterized in that in addition there are fed to the reactor the whole or part of sulphur-containing and/or sulphur- and sodium-containing materials present in the pulp mill, including sulphur-containing and/or sodium- and sulphur-containing make-up chemicals used for the total chemicals balance of the pulp mill, in such a way that the mole ratio of sodium to sulphur in the total mixture fed to the reactor is within the range of 1.5 to 4.

Abstract: A simplified method and apparatus for handling black liquor (or other spent liquor from the pulp industry) includes utilization of a mixing tank directly with a black liquor storage tank. The mixing tank has a side wall defined by a part of the side wall of the black liquor storage tank, and the mixing tank may either be disposed within the volume of the storage tank, or immediately exterior of it. Fly ash from a recovery boiler and make-up chemical are introduced into the mixing tank along with black liquor from evaporators, and the mixed liquid from mixing tank overflows into the interior volume of the black liquor storage tank. From the storage tank the black liquor is sent to a recovery boiler where it is burned. Also, some black liquor from the recovery boiler is recirculated to the storage tank, and introduced into the storage tank remote from the mixing tank.

Abstract: The invention relates to a twin-wire web former for a paper machine wherein a covering wire and a carrying wire form a twin-wire forming zone between them. A method for dewatering a web is also disclosed. In the invention, water is drained out of a web running through the twin-wire zone through both of the wires. After the twin-wire zone, the web is separated from the covering wire and is transferred on the carrying wire to a pick-up point. In hybrid formers, after an initial single-wire forming zone preceding the twin-wire zone, and in gap formers, after a curved forming zone placed directly after a forming gap, there is a forming shoe provided with a ribbed deck and arranged inside one of the wire loops. This forming shoe is followed by dewatering and web forming units which include forming ribs and are placed inside both of the wire loops. At least one of the dewatering and web forming units is loaded by means of a pressure-hose arrangement.

Abstract: The invention is directed to a paper machine for the production of a fiber web, including a headbox for forming the fiber web. Disposed adjacent the headbox is either a dewatering unit, e.g., a dewatering cylinder, a double wire former or a four-drinier wire section. Also provided are at least one press unit for dewatering the fiber web, a tissue drying cylinder for finish drying the fiber web, a device for fiber web pickup from the tissue drying cylinder (Yankee cylinder), e.g., a creping doctor or a Clupak device, and a carrier belt for carrying the fiber web. At least one of the press units is configured as a shoe press for drying the fiber web, and includes a device for immediately separating the fiber web from a press felt after at least one press pass. The belt is preferably water impermeable, and an adhesion force between the water impermeable belt and the fiber web is greater than an adhesion force between the press felt and the fiber web.

Abstract: Improved system for controlling the forming and dewatering of a web of paper by submerged drainage in which air does not penetrate the fiber/aqueous dispersion and the formed web. The dewatering is via altering the natural tension of the meniscus of the water to induce enhanced drainage of water from the aqueous dispersion of paper making fibers in the wetter end of the system and from the drier end of the fabric. Also, the improved horizontal system provides substantially equivalent side surfaces to the paper formed in such system.

Abstract: Improved apparatus for controlling the dewatering of a web (44, 44') in a Fourdrinier fabric (20, 21) by submerged drainage apparatus in which air does not penetrate through the fiber/aqueous dispersion nor the formed web (44, 44'). The dewatering is accomplished by altering the natural tension of the meniscus of the water to induce enhanced drainage of water from the aqueous dispersion of paper making fibers in the fabric (20, 21) and replacement air for the water draining from the formed web (44, 44') is provided from beneath the lower fabric (20) and, if an upper fabric (21) is employed, from above the upper fabric (21).

Abstract: In a twin-wire former for the production of a paper web, two wire belts (11 and 12) together form a twin-wire zone which is divided into three sections (I, II and III). In the first section (I) the two wires (11, 12) travel over a curved forming shoe (16). They form there a wedge-shaped inlet slot (15) with which a headbox (10) is directly associated. In the second section (II), several resiliently supported strips (27) rest against the lower wire (11) and between each of said strips (27) a rigidly mounted strip (28) rests against the upper wire (12). In the third section (III) both wire belts (11, 12) pass over another curved forming shoe (23).

Abstract: The invention concerns a twin-wire web former in a paper machine, comprising a carrying wire and a covering wire which together form a twin-wire forming zone. In this forming zone, a forming unit is fitted, which comprises a forming board and a drainage box placed one opposite the other. In the forming board placed facing the drainage box there are a number of transverse loading ribs placed at a distance from each other. Subsequent transverse loading ribs are interconnected by intermediate parts which, together with the transverse loading ribs form ribbed shoes. These shoes can be loaded by means of loading hoses to produce a dewatering pressure in the web (W) placed between the wires. In the area of the forming unit the dewatering takes place both through the covering wire and through the carrying wire also toward the forming board through the open spaces placed between its transverse loading ribs.

Abstract: A pulp mill has zero or minimum liquid discharges. The large amounts of liquid that must be processed to achieve this result are handled utilizing a multiple effect evaporator provided with heat from a steam exhaust of a condensing type steam turbine. Super heated steam from the recovery and bark boilers is fed to the turbine to generate electricity for the production of bleaching chemical and other uses in the mill. Three or four steam exhausts having different composite temperature and pressure values are taken from the turbine and used where most suitable in the pulp mill. For evaporation of bleach plant effluent the steam taken from the turbine preferably has a pressure of about 1-3 psia and a temperature of about 120.degree.-140 .degree. F, and has no significant adverse affect on power generation.

Abstract: Lime mud from kraft pulp recovery operations is processed using dielectric hysteresis heating, in a two-stage operation, in which wet lime mud first is dried then the dried lime mud is decomposed to lime and carbon dioxide. A two-zone lime mud calciner is employed in which the lime mud is conveyed horizontally, with drying being effected in the first zone and then decomposition being effected in the second zone. A co-current flow of purge air removes steam generated in the first zone and a counter-current flow of purge air removes carbon dioxide generated in the second zone.

Abstract: A direct monitoring and control method is provided for on-line measurement of effective alkali, carbonate, sulfate and thiosulfate concentrations in process liquors for the production of kraft pulp. The control method eliminates frequent sampling, and the need for frequent equipment maintenance. The method includes the steps of withdrawing samples of a liquor from the kraft manufacturing process, subjecting the samples to infrared spectrophotometry at predetermined wave numbers to produce peak-absorbance measurements relative to a background spectrum of water, determining peak absorbance for different alkali concentrations, correlating relationships between the peak-absorbance measurements of samples with the peak absorbance for different alkali concentrations to determine optimum effective alkali in the samples, and controlling at least one process parameter to obtain effective alkali of the liquor.

Abstract: Apparatus for a pulp and paper mill, and methods of acting on liquid effluents produced in the mill, which minimizes the discharge of polluting gaseous and liquid effluents to the environment. Liquid effluents from the bleach plant are concentrated (e.g. evaporated), incinerated (e.g. gasified), leached, crystallized (e.g. freeze crystallized) then washed, and then fed to the plant chemical recovery loop. White liquor produced from the recovery boiler melt is fully oxidized and used in place of caustic in the bleach plant. Essentially all sulfuric acid, sulfur dioxide, caustic, and chlorine dioxide necessary for the pulp mill is produced from mill liquid effluents and gas waste streams, on site at the pulp mill. Typical bleaching sequences that can be used are DE.sub.op D.sub.n D, or AZE.sub.o PZP.

Abstract: A method and apparatus for generation of electricity by pressurized gasification of black liquor in a combined power plant. The gases produced in the gasification of black liquor are purified and introduced into a gas turbine for generating electricity. From the turbine, the gases are conducted to a waste heat boiler. High pressure steam generated in the waste heat boiler and or auxiliary boiler is introduced into a steam turbine to such an extent that the exhaust steam from the steam turbine covers the steam and heat demands of the pulp mill. The excess steam is introduced into the gas turbine or the combustor thereof for increasing the generation of electricity.

Abstract: A process and reactor for recovering energy and chemicals from spent liquor obtained in pulp production by thermal decomposing the spent liquor are described, said decomposing being carried out in a reactor at a pressure of from atmospheric pressure up to 150 bar and at a temperature of 500.degree.-1500.degree. C. so that a gas and solid and/or molten inorganic material are formed, said gas being rich in energy to be used as fuel or being useful as raw material for chemical production. According to the invention the thermal decomposition of the spent liquor is carried out during exposure to low frequency sound and without or with simultaneously supply of oxygen or a gas containing oxygen in an amount below that stoichiometrically required for complete oxidation of the substances formed at the thermal decomposition. The reactor comprises at least one sound generator arranged to generate low frequency sound in the reactor.

Abstract: A direct monitoring and control method is provided for on-line measurement of effective alkali, carbonate, sulfate and thiosulfate concentrations in process liquors for the production of kraft pulp. The control method eliminates frequent sampling, and the need for frequent equipment maintenance. The method includes the steps of withdrawing samples of a liquor from the kraft manufacturing process, subjecting the samples to infrared spectrophotometry at predetermined wave numbers to produce peak-absorbance measurements relative to a background spectrum of water, determining peak absorbance for different alkali concentrations, correlating relationships between the peak-absorbance measurements of samples with the peak absorbance for different alkali concentrations to determine optimum effective alkali in the samples, and controlling at least one process parameter to obtain effective alkali of the liquor.

Abstract: Black liquor from a cellulose pulp processing plant is treated, including by using a direct contact (cascade) evaporator, without need for oxidizing the black liquor, without substantial sulphur emissions at the cascade evaporator, and by maximizing the solids content of the black liquor so that the loss of heating value of the black liquor is minimized. The black liquor is heated under temperature and time conditions sufficient to drive off most of the organic sulphur compounds as off gases, which gases are converted primarily to methane and hydrogen sulfide, with the methane separated by selective absorption in white liquor. The black liquor is then stripped of most remaining sulfur by bringing it into stripping contact with flue gases from the recovery boiler, the flue gases taken from downstream of the direct contact evaporator.

Abstract: A blade mounting frame is attached to a support structure having an endless forming wire rotatably mounted thereon. At least one turn shoe is mounted to the support structure for guiding the rotating path of the forming wire. A blade assembly attached to the blade mounting frame includes a blade in contact with the wire for removing debris from the forming wire before the debris is caught at a nip between the rotating wire and the turn shoes.

Abstract: The present invention relates to a process for partial combustion of cellulose spent liquors using a burner equipped with a liquor lance and an atomizing nozzle, which burner is connected to a reactor operating at pressures in the range of 1.1 to 150 bars while supplying an oxygen containing gas, whereby the weight ratio between the oxygen containing gas supplied through the burner and the spent liquor solids supplied through the burner is less than 2:1, and that at least half of the non-fuel bound oxygen required for the partial combustion is discharged into the reactor through the atomizing nozzle.

Abstract: A process for bleaching wood pulp is provided comprising subjecting the wood pulp, after brown stock washing, to an oxygen delignification stage, a washing sequence, a first chlorine dioxide bleaching stage, an oxidative extraction stage, at least one final chlorine dioxide bleaching stage and then recycling the filtrate from the oxidative extraction stage countercurrently through the bleaching plant and brown stock washing. Additionally, and quite beneficially, the filtrate from the first chlorine dioxide bleaching stage is also recycled countercurrently through the brown stock washing thereby significantly reducing the environmental impact associated with the manufacture of bleach wood pulp.

Abstract: Chemicals are recovered during the production of cellulose pulp by forming two different sulfidity melts in two different sections of a soda recovery boiler, and then producing cooking liquors from different melts in dissolving tanks. The liquors may be causticized and/or oxidized, or may be utilized uncausticized. Uncausticized green liquor having a sulfidity of about 70-90% may be used early in a kraft cooking cycle, followed by treatment with low sulfidity oxidized and causticized white liquor. In the continuous digestion of cellulosic pulp, oxygen may be added to the recirculation loops below the black liquor withdrawal to enhance the alkalinity of the slurry and to assist in delignification. Oxidized cooking liquor with low sulfidity can be added to oxygen bleaching and alkali extraction stages downstream of the digester, and a portion of the high sulfidity cooking liquor can be used to produce acid used in an ozone bleaching stage.

Abstract: In a Fourdrinier paper making system where all of the water from the stock slurry is removed in one direction downwardly through the paper web, a sheet forming unit, including two spaced dandy rolls with a pocket roll inbetween, is added to press a secondary fabric downwardly on the top surface of the paper web. The pocket roll cooperates with a suction box below the paper web to remove water while the web passes over a low vacuum section and then over a high vacuum section and then over a low vacuum section of the suction box. This treatment produces a better internal bond between the fibers in the paper web and also produces better surface properties.

Abstract: Sodium sulphate and/or sodium carbonate containing material from a cellulose pulp mill, such as fly ash from a recovery boiler, or a by-product from a chlorine dioxide production plant, is brought into contact with a a gas containing hydrocarbons and/or hydrogen sulphide which chemically reacts with the material to produce sodium sulphide. Preferably the gas contains one or both of ethene and hydrogen sulphide. The sodium sulphide produced is used to effect sulphate cooking of cellulose pulp. The gas may be brought into contact with the melt of a soda recovery boiler to increase its sulphidity, either prior to, after, or simultaneously with bringing the gas into contact with the material. The sources of the fly ash and melt may be a soda recovery boiler combusting black liquor under oxidizing conditions.

Abstract: A hydraulic support device in a paper making machine for supporting a first beam (52) on a second beam (53), having a pressure cushion (54) between the two beams. The pressure prevailing in the pressure cushion is variable but it is uniform over the entire length of the pressure cushion. The pressure cushion (54) rests on a contact surface of the first beam (52). The width (b) of the contact surface as seen in cross section is less than the total width (B) of the pressure cushion (54). A free space (55) into which a loop of the pressure cushion (54) can penetrate is provided on each side of the contact surface.

Abstract: In order to regulate dewatering of the fiber suspension and the formation of the paper web between the upper and lower wires of the papermaking machines, upper ledges are provided along with the upper wire. These upper ledges are particularly constructed so as to have uniform design. Between these upper ledges, there is left free the same distance or spacing. This distance is not smaller than the width of each upper ledge. The individual distances between the upper ledges can be closed by insertable inserts so that the dewatering can be forcibly accomplished at mutually separated zones. Along the lower wire, there are provided lower ledges at a table, and between these lower ledges, it can be adjusted varying distances or spacing therebetween. The mutual distance or spacing between the lower ledges, according to a favorable construction, is always greater than the width of the individual upper ledges plus the distance or spacing of an upper ledge from the next neighboring upper ledge.

Abstract: In a known method of rebuilding a conventional tissue machine having a conventional C-wrap type twin wire forming section to a TAD machine, a TAD section, which includes a looped TAD fabric (24) and at least one TAD cylinder (22) located inside of the TAD fabric loop for thermally predrying the formed paper web (13) by passing hot air through the web, is incorporated in the machine.

Abstract: A twin-wire former for a paper machine having two endless loop wires, a wire support frame and a head box. The web forming zone leading from the entrance slot, which is at the breast roll in one wire loop and the forming roll in the other wire loop, is inclined at an angle of 30.degree. to 50.degree. to the horizontal. The wire support frame has the shape of an inverted U with a front support arranged upstream of the head box, a rear support arranged downstream of the headbox and an upper beam which connects the upper ends of the front and rear supports to each other. A lower beam is located within the loop of the lower wire and extends to both of the forward and rearward sides of the rear support with one end extending into the U-shaped frame while the other end extends at least approximately up to the remote end of the loop of the lower wire. At least one water removal element of the upper wire is suspended from the upper beam. At least one water removal element of the lower wire rests on the lower beam.

Abstract: Chloride dioxide for a cellulose pulp mill bleach plant is produced by concentrating (evaporating) liquid effluents from the bleach plant to a concentration level high enough for incineration, incinerating the concentrated effluents to produce an ash, chemically reacting at least a part of the ash to produce chlorate, and using the chlorate in the manufacture of chlorine dioxide. The ash is purified to produce sodium chloride and the sodium chloride is reacted with oxygen and external energy to produce sodium chlorate. The chlorate is then used in the manufacture of chlorine dioxide. Sulfates produced are used to manufacture acid and/or caustic, and heavy metal hydroxides are disposed of. A part of the ash may be used directly in chlorine dioxide manufacture. At least some of the salt from chlorate manufacture may be fed to the chemical recovery loop, including a recovery boiler, in the pulp mill. Evaporated gases may be returned to the pulp mill and bleach plant.

Abstract: A black liquor gasification system intended for use as a replacement for a Tomlinson cycle, Chemical Recovery Unit, and which operates at a temperature below the ash melting temperature thereby removing the potential for smelt-water reactions and explosions. The subject black liquor gasification system is based on the use of a circulating fluidized bed operating at atmospheric pressure that produces dry, recoverable salts as well as low calorific gases to be used within the paper-making process.

Abstract: The wet section of a twin wire papermaking machine is provided with an open forming roll at the lower wire and with the combination of a suction box at the lower wire and a vacuum suction box at the upper wire. Furthermore, by selecting the elevational position or level of the individual wire sections there can be obtained particularly advantageous conditions for the operation of the papermaking machine throughout a wide field of application, especially heavy types of paper at relatively low operating velocities of the papermaking machine. Gap-former and hybrid-former constructions of the papermaking machine are possible.

Abstract: A dewatering device for the web-forming or wet section of a papermaking machine comprises foils arranged transverse to a forming wire, that is to say, extend in the cross-machine direction. Force or powering elements act upon the foils so as to exert a force or pressure upon the forming wire, and thus, bring about dewatering and sheet formation of a layer of fiber stock suspension reposing upon the forming wire. The force elements are constructed and positioned such that additional moments are generated which counteract tilting moments produced by the frictional force present between the foils and the forming wire. In certain arrangements, the force elements also can be interconnected with one another.

Abstract: A twin wire former wherein the forming turbulence of a first forming section is quieted by a main forming roller. Behind the main forming roller, as viewed with respect to a predetermined direction of travel of the forming wires, there is accomplished a further forming of the paper web or sheet from the fiber stock suspension in a second forming section. Due to this arrangement there is possible optimum formation of the paper web or sheet with the use of very little dilution water for the fiber stock suspension. Additionally, due to intensive shear forces present in the second forming section flocks formed in the fiber stock suspension and the paper web or sheet at the region of the main forming roller, can be eliminated so that the structure of the paper web or sheet is made more uniform.

Abstract: A wire or felt forming section of a paper-making machine has breast rollers for guiding a respective one of two forming wires. The two rollers are disposed with a pulp gap formed between the two rollers and the wires are disposed just downstream of a pulp suspension ejecting nozzle of a headbox. Each roller is supported against the respective taut forming wire by a hydrostatic bearing. The hydrostatic bearing has two circumferentially separated resiliency chambers provided in a combined region of resiliency disposed over an arc of the circumference of the roller. A sealing strip after the region of resiliency prevents fluid from contacting the wire.

Abstract: A twin wire sheet-forming apparatus for a paper machine having at least two fixed hydroextractors which have separate places for drainage to the hydroextractor side from places for dispersion of fibers. These hydroextractors are arranged alternately in the two wire loops, and have shoe blades, with a wedge shaped trough in a mid-portion of each shoe blade. The wires do not bend at a front leading portion of each shoe, yet do bend at the mid-portion or back portion of each shoe for generating a pressure pulse to disperse the fibers.

Abstract: The invention disclosed here is a process or system for treating the effluent from a BCTMP pulp mill. The effluent is evaporated to produce a water condensate and a remaining waste product concentrate. The condensate is recycled for use in the BCTMP mill, or is dumped into the environment. The concentrate is incinerated in a recovery boiler. Incineration results in the recovery of certain reusable chemicals. At least some of such chemicals are fed back into the effluent while it is being evaporated, to buffer it, and thereby prevent the carryover of undesirable organic acids into the condensate. This ensures sufficient condensate purity for recycling it in the BCTMP process, or for otherwise dumping it into the environment.

Abstract: The invention relates to a process for the recovery of heat and chemicals from a mixture of ashes and spent liquor by carrying out the final concentrating (2) of the liquor, and its feeding (8) into the soda recovery unit (5), under pressure and at a temperature higher than the atmospheric boiling point of the liquor. According to the invention, the ashes (1) are not mixed with the waste liquor (7) until after the final concentrating (2) of the liquor, and the mixture is further expansion evaporated (4) before the thus concentrated pressurized liquor is fed into the soda recovery unit (5).

Abstract: A paper machine for manufacturing a soft crepe paper web, comprising a wet end (1) having a forming wire (4) for forming and carrying a paper web (7), and a drying section (2) provided with a drying cylinder (12), said paper machine having a first operating arrangement for manufacturing a soft crepe paper web with certain bulk and softness values, in which first operating arrangement the drying section has a felt (13) arranged to run in a loop from a pick-up roll (14) at the transition between the wet end and drying section, to a press roll (15) at the drying cylinder, and the carrying forming wire runs up to the pick-up roll (14) to transfer the paper web to the felt (13).

Abstract: A method and apparatus for improved dewatering of a papermaking stock in a web forming section of a papermaking machine including directing a stock jet stream into the head end of a run between opposed looped forming wires traveling in a substantially parallel forming run passing over a curved vacuum forming box and thereafter passing over one or more pressure locations with a pressure dome on one side and a water collecting chamber at the other side of the wires with the pressure dome in one form divided into compartments each applying an increasing pressure to the wire and stock between the wires with the air pressure being heated such as by being delivered from the dryer section and the wires separated slightly following the pressure location with a last smaller pressure compartment transferring the web to one of the wires and the wire carrying the web thereafter turning over a couch roll and the other wire carried over a turning roll.

Abstract: A twin screen paper forming apparatus is provided having upper and lower screens moving in a first direction and wrapping around a portion of a leading forming roller positioned at the beginning of a forming zone where the upper and lower screens converge to form a twin screen. At least one stationary forming element is positioned downstream of the leading forming roller to contact with the lower screen. A water guide element is also located in the region of the forming zone approximately at the start of the forming zone. At least one forming rail contacts the upper screen and a pulp suspension discharge nozzle is positioned, to prevent preliminary draining, upstream of the location where the upper and lower screens converge.

Abstract: A device for supporting a plurality of dewatering elements contacting a lower surface of a paper-making belt, wherein the plurality of dewatering elements are pivotably connected with each other through a link, the dewatering elements each being aerially supported by a stand, the stand being provided with a jack capable of reciprocally moving upwardly and downwardly, an upper end of the jack being pivotably connected to the link so that each of the dewatering elements can be aerially supported thereon, the link being pushed up and pushed down by the upward and downward movements of the jack, thereby adjusting inclination of each dewatering element.

Abstract: A twin-wire web former in a paper machine includes a covering wire and a carrying wire defining a forming zone, at the beginning of which zone there is a forming gap into which the discharge opening of a headbox feeds a pulp suspension jet. A first forming roll is located on the twin-wire zone, in the area of the forming gap, on which the twin-wire zone is curved within a certain sector, followed by a dewatering unit(s), which is in turn followed by a second forming roll(s) in the twin-wire zone. Thereafter, the web is detached from the covering wire and passed on the carrying wire to a pick-up point. Between the first forming roll and the second forming roll(s), a dewatering unit(s) is provided which comprises a press-support unit which guides the wire that enters into contact with the unit as a straight run. The dewatering unit(s) also includes a dewatering equipment facing the press-support unit and provided with suction and foil equipment for removing a substantial amount of water out of the web.

Abstract: A wire loading device in a paper machine, by whose means a mechanical load is applied to the wire of the paper machine across its entire width, is disclosed. By means of this load, a pressure pulse is applied to the fiber layer or web supported by a wire or between wires. By means of the pressure pulse, the dewatering of the web is promoted, the formation of the web is improved, and/or the transverse profiles of different properties of the web are controlled, such as the transverse profiles of dewatering, filler distribution, formation, and/or retention. The loading device includes a plate-shaped spring blade, whose side is arranged as substantially parallel to the run of the wire or wires. The spring blade is adapted to drag against the inner face of a wire loop to produce a pressure pulse. The spring blade is attached, from outside its dragging area, to a frame part of the loading device.

Abstract: The present invention relates to a process for the separation of sulphur and sodium compounds from a hot process gas generated during gasification of spent liquor from the kraft pulping industry, through contact with hydrogen sulphide ion and hydroxide ion containing alkaline liquids in two or more stages, whereby the process gas in a first stage passes through a venturi throat and/or liquid trap where it is brought into contact with an alkaline washing liquid, whereby melt droplets in the process gas are separated from the gas flow and drawn off as an aqueous solution, whereby the process gas in a subsequent washing stage is brought into contact with a finely dispersed washing liquid containing hydroxide ions and hydrogen sulphide ions with a molar ratio greater than 4:1.

Abstract: In a twin-wire former in a paper machine, an operation of a hybrid former mode and that of a gap former mode are conducted, and papers of quality conforming to the kind of papers can be made in a wide range of basis weight with regard to multiple kinds of papers.In the twin-wire former, a forming roll, which guides a top wire so that it can approach to a bottom wire to pinch the stock of paper and run approximately horizontally, is made adjustable in an up and down direction.Upper surfaces of blades of a forming board and a forming shoe provided inside a loop of the bottom wire, are upwardly convex so that dewatering can be effected mainly downward.

Abstract: Nozzles for directing a jet of steam against a spout flow stream of sodium recovery boiler smelt are secured to an articulating anchor mount for the purpose of maximizing the shattering impact of the steam jet upon the smelt flow stream under a wide range of boiler operating conditions.

Abstract: A method of rinsing a slurry contained between a pair of converging mesh belts comprising the steps of splitting the slurry into two streams, each stream adjacent one of the converging mesh belts, introducing a stream of rinsing fluid between the two slurry streams, the point of introduction of the rinsing fluid between the two slurry streams is not more than 12 inches before and not more than 72 inches after the slurry streams contact the converging mesh, and creating compressive forces within the pair of mesh belts, which compressive forces continue for a distance of at least 24 inches after introduction of the stream of rinsing fluid.

Abstract: A saveall apparatus is disclosed for collecting water ejected from stock through a forming wire of a papermaking machine. The apparatus includes a box which is disposed closely adjacent to the forming wire. The box defines an enclosure which is connected to a source of partial vacuum so that water ejected from the stock is collected within the enclosure. A throat wall is rigidly secured to the box and has an upstream and a downstream end. The upstream end of the throat wall slidingly engages the forming wire. A moveable throat wall cooperates with the throat wall for defining therebetween a vacuum slot which is connected to the enclosure such that the water ejected from the stock is drawn by the partial vacuum through the vacuum slot into the enclosure. The throat wall is disposed in a first plane, and the moveable throat wall is disposed in a second plane such that when the moveable throat wall is moved relative to the throat wall, an angle defined between the planes remains constant.

Abstract: A twin wire forming apparatus for forming a web from stock having an ash content above 20% has upstream end disposed closely adjacent to a headbox. A curved shoe cooperates with a second wire and is immediately downstream relative to the upstream end of the forming section. The second wire is between a first wire and the shoe, so that a first portion of water is removed through the first wire when the wires and the stock move over the shoe. A dewatering device is between the shoe and the downstream end of the forming section and cooperates with the first wire and is on the opposite side of the wires relative to the shoe. The dewatering device has a curvature which is less than, and opposite to that of the curved shoe. A second portion of water is removed from the stock through the second wire during movement of the stock and the wires over the dewatering device.

Abstract: Method of feeding separate streams of (1) an aqueous dispersion of pulp and (2) white water from a paper making process into a wedge-shaped space between horizontal travelling upper and lower converging wire meshes, applying a siphon means to the upper wire mesh in said zone to form a web of solid fibrous material between the meshes separating the upper wire mesh from the web to leave it supported on the lower wire mesh as the meshes leave the wedge-spaced zone; washing all solids from the wire meshes into a receiving vessel, recycling the contents of the receiving vessel to the paper making process, and recycling the liquid from the white water to the paper making process; and apparatus to perform the above method.

Abstract: A means for controlling wires in a twin-wire section in a paper or cardboard machine where the wires run over the other for dewatering stock that is present between the wires, where a dewatering box is provided on one side of the wires and where a number of strips disposed side by side are provided on the other side of the wires, said strips running across the transport direction of the wires and over the total width of the wires, and where the strips have been arranged to be pressed against the wire lying closest to the strips, with the aid of pressure elements, where said pressure elements are disposed to act between the strips and a supporting table or equivalent, said supporting table being fixedly mounting relative to said dewatering box.

Abstract: The de-watering apparatus for a two-wire paper machine is constructed in such a manner that following the convergence of both wires, firstly, a uniform pressure at a forming roll is exerted on the suspension layer located between the wires. Subsequently, both wires pass de-watering rails which may be located in the upper and/or the lower wire. In this case, an under-pressure is exerted at least at the rails located in the upper wire. At least one further de-watering member then follows before both wires are separated again. The de-watering apparatus can also be used after a preliminary de-watering section, for example an endless wire, and also in the direct vicinity of a head box.