Abstract: A doctor blade structural support has the form of a hollow structural member of roughly triangular cross-section, one side of the triangular cross-section being substantially tangent to the surface of the dryer roll. A quantity of water is disposed within the hollow structural member and resides on the inside surface of the structural member adjacent to the heated dryer roll surface. The interior of the doctor support structure is sealed from the atmosphere and is evacuated so that the interior of the structure contains only water and water vapor. Heat radiating from the dryer roll surface to the doctor support structure causes water disposed on the inside surface adjacent to the dryer roll to evaporate, thus raising the internal vapor pressure in the sealed interior of the doctor support structure. The water vapor continuously condenses on the inside surfaces of the support structure which are not exposed to radiant heating from the dryer roll.

Abstract: A method and apparatus for cleaning the forming fabric used on a papermaking machine includes a chamber surrounding a span of the forming fabric on either side thereof. A source of sub-atmospheric air pressure is connected to the chamber for removing water mist surrounding the fabric. Mounted within the chamber is a pair of high pressure-low volume water impingement showers in substantially opposed array for directing jets of relatively high pressure water against the forming fabric as the forming fabric passes through the chamber via slots on either end thereof. In a preferred embodiment, downstream of the pair of high pressure needle showers is a second shower apparatus comprising a relatively low pressure-high volume flooding water shower to direct a water spray against the inner side of the looped forming fabric to flood the interstices of the forming fabric with water to wash out pulp fibers therefrom.

Abstract: A cleaning apparatus is disclosed for cleaning a forming wire of a paper machine. The apparatus includes a shower which is disposed adjacent to the forming wire for applying a shower of cleaning fluid to the wire. A blow box is disposed closely adjacent to the forming wire and downstream relative to the shower. The box is connected to a source of pressurized air for blowing a jet of air through the wire for removing the cleaning fluid therefrom. A plate is disposed between the box and the wire. The plate defines a plurality of slots which are disposed obliquely to a direction of movement of the wire in order to supply a multiplicity of pressure pulses to the wire for removing contaminants therefrom.

Abstract: The dryer section in a papermaking machine has a single tier of all top felted dryer rolls six to nine feet in diameter. Air caps are employed over the dryer rolls to simultaneously dry both sides of the web to prevent curl and to increase drying rates. The air caps employ blown air at a temperature of 250-900 degrees Fahrenheit and air speeds of 8,000-40,000 feet per minute. The dryer fabric employed is foraminous with a permeability of between 300-1,200 cubic feet per minute per square foot and is designed to withstand peak temperatures of up to 900 degrees Fahrenheit and average temperatures of between 500-600 degrees Fahrenheit. A single transfer roll, or more advantageously, two grooved vacuum rolls in a vacuum box are disposed between the dryer rolls to maximize the circumferential wrap of the web and, at the same time, support and transport the web between dryer rolls.

Abstract: The dryer section in a papermaking machine has a single tier of all top felted dryer rolls six to nine feet in diameter. Air caps are employed over the dryer rolls to simultaneously dry both sides of the web to prevent curl and to increase drying rates. The air caps employ blown air at a temperature of 250-900 degrees Fahrenheit and air speeds of 8,000-40,000 feet per minute. The dryer fabric employed is foraminous with a permeability of between 300-1,200 cubic feet per minute per square foot and is designed to withstand peak temperatures of up to 900 degrees Fahrenheit and average temperatures of between 500-600 degrees Fahrenheit. A single transfer roll, or more advantageously, two grooved vacuum rolls in a vacuum box are disposed between the dryer rolls to maximize the circumferential wrap of the web and, at the same time, support and transport the web between dryer rolls.

Abstract: A dryer section employs top-felted and bottom-felted dryer sections each comprised of a single steam-heated drying cylinder with a diameter of about 12 feet. The web is transferred between drying cylinders by a two vacuum roll transfer without an open draw. The dryer fabric wrap on the large dryer cylinders is over 270 degrees resulting in large drying capability per dryer roll. Because each large dryer is followed by another large dryer roll which dries the opposite side of the web, uniformity of drying is maintained. Each dryer cylinder may have its own dryer fabric stretcher and guides. Alternatively, individual dryer fabrics service multiple top-felted dryers and bottom-felted dryers respectively. The web is constrained approximately 96 percent of the time as it passes through the is dryer section. The dryer section can achieve 2.9 inches of dryer surface in the machine direction for every inch of dryer section.

Abstract: A cleaning apparatus is disclosed for cleaning and removing contaminants from a forming wire of a paper machine. The apparatus includes a shower which is disposed adjacent to the wire for supplying a cleaning fluid onto one side of the forming wire. A leading blade is disposed downstream relative to the shower. The leading blade contacts the wire on the one side of the wire and extends in a cross-machine direction across the wire. A trailing blade is disposed downstream relative to the leading blade. The arrangement being such that the leading blade and the trailing blade defined therebetween a cross-machine directional slot. The slot is connected to a source of pressurized air so that the pressurized air flows through the slot and through the wire for removing the cleaning fluid and the contaminants from the wire. Furthermore, the trailing blade and the wire define therebetween a wedge shaped gap which converges in a direction from the slot and away from the leading blade.

Abstract: A cleaning apparatus is disclosed for cleaning a forming wire extending around a wire turning roll of a paper machine. The apparatus includes a shower which is disposed upstream relative to the turning roll for spraying a cleaning liquid onto the forming wire. A housing is disposed between the shower and the turning roll, the housing being connected to a source of pressurized air. The housing defines an opening which has a first and a second end. The housing also defines an orifice which has an upstream and a downstream end for permitting a flow therethrough of the pressurized air such that the flow of air is directed against the wire for at least partially removing the cleaning liquid therefrom. The opening cooperates with the turning roll such that the opening conforms with the turning roll for substantially sealing the opening against loss of the pressurized air so that the flow of pressurized air is directed through the orifice.

Abstract: A new dryer section or an existing dryer section of the two tier double-felted type has air caps disposed over the upper dryer rolls to simultaneously dry both sides of the web to increase drying rates. The heated pressurized air is blown through multiple air impingement holes in the air cap nozzle plates to impinge the web at a temperature of 500-900 degrees Fahrenheit and air speeds of 20,000-40,000 feet per minute. The dryer fabric employed is foraminous with a permeability of between 400-1,200 cubic feet per minute per square foot and is designed to withstand peak temperatures of up to 900 degrees Fahrenheit and average temperatures of between 500-600 degrees Fahrenheit. The design of the air caps utilizes recirculation of the blowing air to control drying rates.

Abstract: A vacuum roll apparatus is disclosed for transferring a web supported on a dryer felt from a first to a second drying cylinder of a dryer section. The apparatus includes a rotatable perforate shell having a first and a second end, the shell defining a cavity which extends from the first to the second end of the shell. The arrangement is such that the dryer felt extends from the first dryer around the perforate shell to the second dryer with the web extending contiguously with the dryer felt, and the dryer felt being disposed between the shell and the web. At least one fin is rigidly secured to the shell and is disposed within the cavity such that when the shell is rotated, the fin generates a flow of air through the perforate shell towards the cavity for drawing the web into close conformity with the dryer felt during movement thereof around the vacuum roll apparatus so that the web is restrained against cross-machine directional shrinkage.

Abstract: The paper dryer section has a single tier of all top felted dryer rolls seven to nine feet in diameter. Air caps are employed over the dryer rolls to simultaneously dry both sides of the web to prevent curl and to increase drying rates. The air caps employ blown air at a temperature of 200-1,000 degrees Fahrenheit and air speeds of 8,000-40,000 feet per minute. The felt employed is foraminous with a permeability of between 300-1,500 cubic feet per minute per square foot and is designed to withstand peak temperatures of up to 1,000 degrees Fahrenheit and average temperatures of between 500-600 degrees Fahrenheit. A single dryer roll, or more advantageously, two vacuum rolls in a vacuum box are disposed between the dryer rolls to maximize the circumferential wrap of the web and, at the same time, support and transport the web between dryers.

Abstract: A single tier drying section apparatus is disclosed for drying a web of paper. The drying section includes a first and a second dryer which are disposed in a single tier for drying the web. A vacuum roll is disposed closely adjacent to and between the first and second dryers for guiding the web from the first to the second dryer. The vacuum roll includes a rotatable roll shell having a first and a second end. The shell defines an outer surface and an internal chamber which extends between the first and the second end of the shell. The shell defines a plurality of channels with each channel extending from the chamber to the outer surface such that the chamber is disposed in fluid communication with the outer surface. A vane mechanism is disposed within the chamber for evacuating the chamber. The arrangement is such that a flow of air flows towards the chamber through the plurality of channels for drawing the web into close conformity with the dryer felt when the web extends around the vacuum roll.

Abstract: A vacuum roll apparatus is disclosed for transferring a web supported on a dryer felt from a first to a second drying cylinder of a dryer section. The apparatus includes a rotatable perforate shell having a first and a second end, the shell defining a cavity which extends from the first to the second end of the shell. The arrangement is such that the dryer felt extends from the first dryer around the perforate shell to the second dryer with the web extending contiguously with the dryer felt, and the dryer felt being disposed between the shell and the web. At least one fin is rigidly secured to the shell and is disposed within the cavity such that when the shell is rotated, the fin generates a flow of air through the perforate shell towards the cavity for drawing the web into close conformity with the dryer felt during movement thereof around the vacuum roll apparatus so that the web is restrained against cross-machine directional shrinkage.

Abstract: A paper drying section utilizes two reversing rolls between each dryer roll to extend the available time for vapor to flash from the web. A vacuum box is disposed between the two reversing rolls to support and dry the felt and paper web as it passes from one reversing roll to another. An air cap is used to blow high velocity air onto the exposed surface of the paper web which is held by the vacuum box. The spacing of the two reversing rolls increases the wrap of the single tier dryer by approximately twenty percent over that of a conventional single tier dryer with a single reversing roll. Another configuration dryer section positions the first of the two reversing rolls downwardly beneath its adjacent dryer roll creating a long draw between the dryer roll and the first reversing roll. This long draw is supported by a vacuum box adjacent the felt.

Abstract: The dryer of this invention employs a vacuum chamber interposed below and between first and second heated dryer rolls. The vacuum chamber has two sides and a top which overlies two grooved reversing rolls. The vacuum chamber controls all flow of air in the gap between and below the dryer rolls. The dryer-fabric-backed paper web passes from the first dryer roll around the reversing rolls and up to the second dryer roll. The dryer fabric seals the vacuum chamber, and air is drawn therefrom. The provision of the grooved rolls permits a greater wrap of the felt around the dryers and the application of vacuum to hold the web against the felt during movement of the web between the dryers and the grooved rolls and between the grooved rolls.

Abstract: A press apparatus and method for pressing water from a paper web is disclosed. The apparatus includes a frame and a first press roll which is rotatably supported by the frame. A second press roll cooperates with the first roll for defining therebetween a pressing nip such that in use of the apparatus, the web extends through the nip for pressing the water therefrom. An elastomeric cover covers at least one of the rolls such that the pressing nip is extended in a machine direction so that the residence time of the web during passage of the web through the nip is increased.

Abstract: An apparatus and method is disclosed for removing fluid from a fibrous web. The apparatus includes a press member and a blanket which cooperates with the press member for defining therebetween an elongate pressing section such that the web is pressed between the press member and the blanket during passage through the pressing section. An elongate shoe urges the blanket towards the press member such that when the web passes through the pressing section, fluid is removed from the web. A heater is disposed adjacent to the press member for transferring heat to the web such that when the web passes through the press section, the web is subjected for an extended period to increased pressure and temperature so that water vapor generated within the pressing section during passage through the pressing section forces the fluid in the liquid phase away from the web. The press member defines a pressing surface which is porous so that delamination of the web is inhibited.

Abstract: A heated extended nip press apparatus and method are disclosed for pressing water from a formed web. The apparatus includes a frame and a backing roll rotatably supported by the press frame. A press device is connected to the press frame and movable relative to the backing roll. The press device cooperates with the backing roll for defining therebetween n extended nip for the passage therethrough of the web. An endless looped blanket extends through the extended nip such that the web is disposed between the blanket and the backing roll. Additionally, the press device includes an arrangement for selectively changing the pressure applied on the blanket along a machine direction relative to a further pressure applied for moving the press device relative to the backing roll such that optimum web properties are obtained and delamination of the pressed web is inhibited.

Abstract: A heated extended nip press apparatus is disclosed for pressing water from a formed web. The apparatus includes a frame and a backing roll rotatably supported by the press frame. A press device is connected to the press frame and movable relative to the backing roll. The press device cooperates with the backing roll for defining therebetween an extended nip for the passage therethrough of the web. An endless looped blanket extends through the extended nip such that the web is disposed between the blanket and the backing roll. Additionally, the press device includes an arrangement for selectively changing the pressure applied on the blanket along a machine direction relative to a further pressure applied for moving the press device relative to the backing roll such that optimum web properties are obtained and delamination of the pressed web is inhibited. Cross-machine direction recesses in the press shoe enable the shoe to be selectively positioned in the machine direction.

Abstract: An apparatus and method is disclosed for removing fluid from a fibrous web. The apparatus includes a press member and a blanket which cooperates with the press member for defining therebetween an elongate pressing section such that the web is pressed between the press member and the blanket during passage through the pressing section. An elongate shoe urges the blanket towards the press member such that when the web passes through the pressing section, fluid is removed from the web. A heater is disposed adjacent to the press member for transferring heat to the web such that when the web passes through the press section, the web is subjected for an extended period to increased pressure and temperature so that water vapor generated within the pressing section during passage through the pressing section forces the fluid in the liquid phase away from the web. The press member defines a pressing surface which is porous so that delamination of the web is inhibited.