Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is superimposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. Also disclosed is the effective mixing of the jets generating cross-machine direction (CD) shear between the rows of jets that form at the outlet of the tubes inside the nozzle chamber of the headbox to align paper fibers in the cross-machine direction.

Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is superimposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. Also disclosed is the effective mixing of the jets generating cross-machine direction (CD) shear between the rows of jets that form at the outlet of the tubes inside the nozzle chamber of the headbox to align paper fibers in the cross-machine direction.

Abstract: Methods and apparatus to condition the paper fiber stock of a wet paper web for enhanced dewatering and formation with an acoustic foil assembly used for removing water and redistributing fibers. A plane ultrasonic wave field is employed for interacting with water suspended pulp and paper fiber stock using acoustic techniques to subject particulate suspensions. The continuous process employees a piezoelectric ceramic transducer to selectively deflect flowing paper fiber stock as they penetrate the ultrasonic field. Depending upon the amount of dissolved gas in water, conditioning is obtained using a traveling wave field to improve paper properties for increased productivity and formation quality with headbox components having hydrodynamic optimization for paper and board forming.

Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is superimposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. A specific flow inside the headbox distributes the fibers in an isotropic form, i.e., uniform in all directions, in the sheet substantially eliminating the MD preferential fiber orientation to produce an isotropic and uniform sheet.

Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is superimposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. Also disclosed is the effective mixing of the jets generating cross-machine direction (CD) shear between the rows of jets that form at the outlet of the tubes inside the nozzle chamber of the headbox to align paper fibers in the cross-machine direction.

Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is superimposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. Also disclosed is the effective mixing of the jets generating cross-machine direction (CD) shear between the rows of jets that form at the outlet of the tubes inside the nozzle chamber of the headbox to align paper fibers in the cross-machine direction.

Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is super imposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. A specific flow inside the headbox distributes the fibers in an isotropic form, i.e., uniform in all directions, in the sheet substantially eliminating the MD preferential fiber orientation to produce an isotropic and uniform sheet.

Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is superimposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. Also disclosed is the effective mixing of the jets generating cross-machine direction (CD) shear between the rows of jets that form at the outlet of the tubes inside the nozzle chamber of the headbox to align paper fibers in the cross-machine direction.

Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is superimposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. Also disclosed is the effective mixing of the jets generating cross-machine direction (CD) shear between the rows of jets that form at the outlet of the tubes inside the nozzle chamber of the headbox to align paper fibers in the cross-machine direction.

Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is superimposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. Also disclosed is the effective mixing of the jets generating cross-machine direction (CD) shear between the rows of jets that form at the outlet of the tubes inside the nozzle chamber of the headbox to align paper fibers in the cross-machine direction, thus increasing CD strength of the manufactured sheet.

Abstract: Coating devices for application of coating material to the surface of a web or a flexible substrate utilizing the study of flow patterns in blade coating to develop high-speed coaters, wherein the coater may be modified to provide an air layer between the coating liquid and any lower boundary. The coater devices of the described embodiments provide two inlet channels and an outlet channel. The first inlet channel carries the coating liquid, and the second channel can be used to pump the carrier fluid, e.g. air, into the coating head to pressurize the chamber and to keep the contact wetting line at the upstream section attached to the substrate. The air layer serves as a carrier fluid removing the wall shear stress on the coating liquid in the channel, and thus the coating flow for the operation of the device may proceed without flow separation from the wall (i.e., in a vortex-free mode) at relatively low flow rates appropriate for commercial applications.

Abstract: Methods and apparatus to enhance paper and board forming qualities with insert tubes and/or a diffuser block in the paper forming machine headbox component which generates vorticity in the machine direction (MD) which is superimposed on the streamwise flow to generate a swirling or helical flow through the tubes of the diffuser block. Tubes of the diffuser block are designed such that the direction of the swirl or fluid rotation of the paper fiber stock may be controlled and the direction thereof is controlled in such a way to provide effective mixing, coalescence and merging of the jets of fluid emanating from the tubes into the converging section, i.e., nozzle chamber of the headbox. Also disclosed is the effective mixing of the jets generating cross-machine direction (CD) shear between the rows of jets that form at the outlet of the tubes inside the nozzle chamber of the headbox to align paper fibers in the cross-machine direction, thus increasing CD strength of the manufactured sheet.

Abstract: The present invention is directed to a coating device for application of coating material to the surface of a web or a flexible substrate. The coating device contains a pressurized channel where a flowing stream of the coating liquid first comes into contact with the substrate. The coating liquid enters the channel at the upstream side and wets the substrate as it flows in the same direction as the substrate. A doctor element is positioned at the downstream side of the channel where the excess coating in the channel follows the contour of the boundary formed by the doctor element and leaves the channel. The geometry of the streamlined boundaries of the coating device eliminate the formation of recirculating eddies or vortices. The elimination of vortices eliminates flow instability due to centrifugal forces and removes harmful pressure fluctuations which could result in coat-weight nonuniformities.

Abstract: The present invention is directed to a coating device for application of coating material to the surface of a web or a flexible substrate. The coating device contains a pressurized channel where a flowing stream of the coating liquid first comes into contact with the substrate. The coating liquid enters the channel at the upstream side and wets the substrate as it flows in the same direction as the substrate. A doctor element is positioned at the downstream side of the channel where the excess coating in the channel follows the contour of the boundary formed by the doctor element and leaves the channel. The geometry of the streamlined boundaries of the coating device eliminate the formation of recirculating eddies or vortices. The elimination of vortices eliminates flow instability due to centrifugal forces and removes harmful pressure fluctuations which could result in coat-weight nonuniformities.

Abstract: A coating applicator for application of coating material to the surface of a web or a flexible substrate. The coating device contains a walled application chamber where a flowing stream of the coating liquid first comes into contact with the substrate. The coating liquid enters a channel of the application chamber at the upstream side and wets the substrate as it flows in the same direction as the substrate. A doctor element is positioned at the downstream side of the channel where the excess coating in the channel follows the contour of the boundary formed by the doctor element and leaves the channel. One of the applicator walls is designed to be a floating or moving wall or belt. The floating applicator wall and geometry of the streamlined boundaries of the coating device eliminates the formation of recirculating eddies or vortices. The elimination of vortices eliminates flow instability due to centrifugal forces and removes harmful pressure fluctuations which could result in coat-weight nonuniformities.