Abstract: A hot soft nip calender apparatus is provided for a paper mill. The apparatus includes at least one heated calender roller and a finishing belt which is moved in proximity to the heated calender roller by a plurality of drive rollers and at least one pressure roller. Thus, a heated calender nip is defined between the heated calender roller and the finishing belt. A web of paper is passed through the nip, such that one surface of the web of paper is contacted by the heated calender roller, while the opposed surface of the web is contacted by the finishing belt. The finishing belt has an extremely smooth surface for contacting the web of paper so as to impart appropriate smoothness and gloss characteristics to that surface. The finishing belt can readily be changed when worn or damaged or to alter the characteristics being imparted to a web of paper.

Abstract: A method of recovering chemicals from spent black liquor used in a kraft pulping process comprising organic materials having oxygen containing functional groups, the method comprising heating the black liquor at an elevated temperature and at a corresponding pressure at which there is no or substantially no boiling of the black liquor, until all or a portion of the oxygen is converted into carbon dioxide to form a slurry comprising microparticulate char and a green liquor suspension. The heating can be accomplished with any suitable means. For example, black liquor is evaporated in an evaporator train, and the liquor pumped in a high pressure pump to a suitable pressure, as for example, a pressure of from about 1200 psig to about 2000 psig. Thereafter, the liquor is transferred to a heat exchanger and heated to the elevated temperature, as for example a temperature of at least about 475.degree. F.

Abstract: A heating element comprising:a body having a heating section;heating means inserted in or adjacent to said body, said means capable of generating heat, having a heat flux Q.sub.1 at a temperature T.sub.1 ; andheat transfer and concentration means capable of transferring said heat from said heating means to said heating section and concentrating said heat in said section such that said section has a heat flux Q.sub.2 at a temperature of T.sub.2, where Q.sub.2 is greater than Q.sub.1 and where T.sub.2 is equal to or less than T.sub.1.

Abstract: A corrugated fibreboard container is provided for packaging a stack of loose paper sheets which comprises a carton and a lid, both formed from two planar blanks. The carton is formed with four sides which define inner dimensions substantially coincident with the dimensions of the paper sheets to be stored therein, with one side being hingedly connected to the bottom of the carton which allows for rotation thereof and access to the stack of loose paper sheets from a point adjacent the hinged side. The container limits the exposure of moisture to the paper sheets stored therein with a moisture resistant coating being disposed on the inner surfaces thereof, special slots, and an adhesive tape being provided for ensuring a tight securement between the lid and the carton. In an alternative embodiment, the lid may be hingedly connected to the carton.

Abstract: A hot soft nip calendar apparatus is provided for a paper mill. The apparatus includes at least one heated calendar roller and a finishing belt which is moved in proximity to the heated calendar roller by a plurality of drive rollers and at least one pressure roller. Thus, a heated calendar nip is defined between the heated calendar roller and the finishing belt. A web of paper is passed through the nip, such that one surface of the web of paper is contacted by the heated calendar roller, while the opposed surface of the web is contacted by the finishing belt. The finishing belt has an extremely smooth surface for contacting the web of paper so as to impart appropriate smoothness and gloss characteristics to that surface. The finishing belt can readily be changed when worn or damaged or to alter the characteristics being imparted to a web of paper.

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: This invention relates to a pallet having a cradle which centers cylindrical articles or materials wound in rolls on the pallet and which allows the rolls to be transported while in a rollingly oriented manner, such that the cradle cooperates with retaining bands extending from a cylindrical core of the article or rolls to notches in runners which are attached to and extend the entire length of the pallet, thereby, securing the rolls in place during transport and storage.

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, optionally at least one final chlorine dioxide bleaching stage and then recycling the filtrate from the oxidative extraction stage counter-currently through the bleaching plant and brown stock washing. Additionally, and quite beneficially, the filtrate from the first chlorine dioxide bleaching stage is also recycled counter-currently through the brown stock washing thereby significantly reducing the environmental impact associated with the manufacture of bleach wood pulp.

Abstract: A method for measuring the size and magnitude of pinholes in a sheet of paper, comprising placing a test sheet of paper on top of a backing sheet and spreading ink, oil or stain across the test paper. Uniform pressure is applied to the test paper in sufficient magnitude to force the ink through any pinholes in the test paper and to create an imprint on the backing sheet. The backing sheet is then removed and allowed to dry. The imprint is then analyzed to determine the number and size of the pinholes in the test paper.

Abstract: A system for continuously monitoring a process such as a paper making process wherein a plurality of video cameras are positioned at various positions along the process to monitor one or more pre-determined characteristics of the process. The system further includes device for converting the monitored characteristics into digital format and a digital data storage device, such as a circular memory, for storage of such data such that as new data is stored earlier stored data is removed. The system includes a control device such as a computer which is capable of communicating with the data storage device and with a detector for detecting deviations from the monitored predetermined characteristic such that on receipt of a deviation signal the control device extracts from the digital data storage device digitized data corresponding to the deviation and displays such extracted deviation digitized data as for example on a video monitor.

Abstract: A heating element comprising:a body having a heating section;heating means inserted in or adjacent to said body, said means capable of generating heat, having a heat flux Q.sub.1 at a temperature T.sub.1 ; andheat transfer and concentration means capable of transferring said heat from said heating means to said heating section and concentrating said heat in said section such that said section has a heat flux Q.sub.2 at a temperature of T.sub.2, where Q.sub.2 is greater than Q.sub.1 and where T.sub.2 is equal to or less than T.sub.1.

Abstract: The invention is a system for monitoring a process in which process data relating to a predetermined characteristic of the process is collected and stored in digital format and extracted based upon a predetermined criterion for display. A plurality of monitors are strategically positioned at various locations of interest to observe the predetermined characteristic. Data obtained by the monitors are converted into digital format and stored. A central control is provided for retrieving the digital data in accordance with a predetermined criterion and transmitting the retrieved data to a display unit. The predetermined criterion for display may be specified as a deviation from the predetermined characteristic, and a plurality of deviation detectors may be coupled to the system for obtaining and relaying information relating to such deviations. Upon deviation, the central control may be adapted to retrieve digital data based on time and location of the deviation.

Abstract: A hot soft nip calender apparatus is provided for a paper mill. The apparatus includes at least one heated calender roller and a finishing belt which is moved in proximity to the heated calender roller by a plurality of drive rollers and at least one pressure roller. Thus, a heated calender nip is defined between the heated calender roller and the finishing belt. A web of paper is passed through the nip, such that one surface of the web of paper is contacted by the heated calender roller, while the opposed surface of the web is contacted by the finishing belt. The finishing belt has an extremely smooth surface for contacting the web of paper so as to impart appropriate smoothness and gloss characteristics to that surface. The finishing belt can readily be changed when worn or damaged or to alter the characteristics being imparted to a web of paper.

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 or ozone bleaching stage, an oxidative extraction stage, an ozone activation stage followed by a chlorine dioxide bleaching stage in the absence of an intermediate washing stage.

Abstract: A method for shutting down and starting up a chemical recovery process of the type comprising burning concentrated black liquor in the furnace of a recovery boiler to produce a flue gas and a hot molten smelt in the bottom of said furnace and discharging the hot molten smelt in a continuous yet variable quantity via a smelt spout into a dissolving tank partially filled with an aqueous solution, said method comprising:inserting an elongated heating element into said spout;shutting down said boiler with said element in said spout such that on solidification of molten smelt in said spout said element is fixed in said solidified smelt; andstarting up said boiler by heating said element to a temperature equal to or greater than the melting point of said smelt to form molten smelt and removing said element from said spout to provide a substantially open spout for discharge of said molten smelt from said furnace.

Abstract: A composite barrier laminate for a carton for citrus juices that extends the shelf life of the citrus juice by inhibiting the proliferation of microbial growth therein. The composite barrier laminate has a plurality of layers with one layer being a thin barrier skin coat in contact with the juice. The skin coat is impervious to the antimicrobial agent D-limonene and is effective to prevent the migration of the D-limonene found in the citrus juice. A method for extending the shelf life of a citrus juice stored in a paperboard carton for preventing the D-limonene present in the citrus juice stored in a carton from migrating into the carton structure by making the innermost layer of the carton impervious to D-limonene is disclosed as is a method for preserving the antimicrobial properties present in a citrus juice that is stored in a paperboard carton formed from a laminate by preventing migration of D-limonene from the citrus juice into the laminate by making the innermost layer impervious to D-limonene.

Abstract: The flow patterns of the wood/paper pulp in a paper pulp treatment tower are controlled to provide for even flow through and discharge of the pulp from the upper end of the tower. Flow-altering fluids are injected into the pulp stock in the tower via appropriately positioned nozzles which create flow-altering fluid streams in the pulp stock. The streams are operable to produce either an inwardly directed pulp flow, or an outwardly directed pulp flow, whichever is desired. The system results in smooth, relatively even movement of the pulp stock from the bottom of the tower to the top, so that each fraction of the pulp mass will spend substantially the same dwell time in the tower, whereby the pulp mass is evenly processed and reacted in the tower. The resultant treated stock is superior to pulp stock treated in a tower without such flow controls.

Abstract: A coating installation is provided for a paper mill to apply a coating to at least one surface of a continuous web of paper. To reduce catastrophic damage to the web of paper passing through the coating installation, a continuous support belt is provided for supporting the web entirely through and beyond the location at which the coating is applied to the web. The continuous support belt is formed from a smooth dimensionally stable material exhibiting appropriate stiffness and compressibility for a particular coating application.