Abstract: A process and an apparatus for removing water from a fibrous web are disclosed. The process comprises providing a fibrous web having a moisture content from about 1% to about 99%; providing an oscillatory flow-reversing impingement gas having a pre-determined frequency; providing a gas-distributing system comprising at least one discharge outlet designed to emit the oscillatory flow-reversing impingement gas onto the web; and impinging the oscillatory flow-reversing gas onto the web through the plurality of discharge outlets, thereby removing moisture from the web. The apparatus comprises a web support designed to receive a fibrous web thereon and to carry it in a machine direction; at least one rotary valve pulse generator designed to produce oscillatory flow-reversing air or gas; and at least one gas-distributing system in fluid communication with the pulse generator for delivering the oscillatory flow-reversing air or gas to the web.

Abstract: Each screen drum design has, in front of the rotating screen drum which transports the web, a stationary screen cover whose purpose is retention of the dry air coming from the fan, uniform throughput of the air through the screen cover, and a uniform drying process over the width of the web. The screen cover has a perforation whose permeability is adapted to the degree of drying. At the beginning of the drying process, when the web is not yet very permeably, the screen cover is to be perforated provided a smaller free air throughput surface and, as the degree of dryness increases, a larger free air throughput surface by making the holes larger in diameter or provided a larger number of holes per unit surface.

Abstract: A method for blowing steam against a paper web, whereby the steam is blown by a steam box having several profiling chambers in the cross direction of a paper machine. The cross-profile of the paper web is controlled by means of the steam supplied by the profiling chambers. A gas flow is provided between the profiling chambers to prevent the steam blown by a profiling chamber from affecting the effective area of the steam blown by the adjacent profiling chamber. Further, a steam box for implementing the method is disclosed.

Abstract: A blow box used in the drying section of a papermaking machine and a method for sealing a pocket provided with a blow box, and a blow nozzle. The blow box is arranged to eject air away from the space between a wire and the blow box and/or maintain an underpressure zone in this space. In the interface between the desired underpressure zone and an outside volume, the blow box is provided with a sealing element, such as a blow nozzle, protruding towards the wire to a certain distance “d” seen from the wire, for forming a seal between the underpressure zone and the area remaining outside the underpressure zone. The sealing element is connected to the blow box so that the element may be moved away from the wire to a distance “D” by a push and/or by an actuator, the distance “D” being greater than the distance “d”.

Abstract: A dry end of a machine for manufacturing a material web, in particular a paper or cardboard web, includes at least one convection drier, having at least one drying section. The material web passes through the at least one drying section, and is guided between two air-permeable wire belts.

Abstract: The air mixer defined herein serves for static mixing of a heated air stream in a flow channel of a circulated air stream upstream of a heat treatment chamber for drying textile goods or tissue webs for example. For this purpose the air mixer is provided with air mixing parts that consist of hollow bodies arranged in the flow cross section of the first air stream with spaces between them, said bodies being provided to receive and conduct the second air stream with inlet openings and outlet nozzles located endwise on one side.

Abstract: Device for treating a fibrous pulp web that includes at least one support face, which is one of moving and stationary. The fibrous pulp web may be guided over the at least one support face. The device also includes at least one sealing device positioned on a side of the fibrous pulp web facing away from the at least one support face to strip at least a majority of a bordering air layer that entrained by the fibrous pulp web. The at least one sealing device may include a sealing disc that is one of substantially straight and at least partially curved, and that is at least one of elastically formed and resiliently mounted.

Abstract: The invention concerns a blow-suction box or equivalent for a paper machine or board machine, which box comprises at least a pressure chamber and which box is placed in the vicinity of a cylinder, roll, or equivalent, from which cylinder, roll or equivalent, a web and/or a wire is/are fitted to run past the box. In connection with the pressure chamber, a nozzle slot has been arranged, out of which a sealing blowing is fitted to be applied towards the cylinder, roll or equivalent and/or towards the web and/or wire running on its face in order to disintegrate the boundary-layer air flow carried along with the web and/or wire. In connection with the nozzle slot, an air guide made of a resilient material has been fitted in order to direct the sealing blowing and to enhance the sealing further.

Abstract: A method and an apparatus for improving the drying capacity of a hood covering a Yankee cylinder (10), when drying a web with a Yankee cylinder while conveying the web over the cylinder by blowing hot air jets against the web at the region of a first hood (12), said hot air jets having a temperature mainly <550.degree. C. The drying capacity of the drying hood is increased by blowing hot air jets against the web conveyed over the cylinder at the region of a second hood, a so called hot air hood (14, 14', 14"), said hot air jets having a a temperature which is higher than the temperature of the hot air jets blown against the web at the first hood, or mainly >550.degree. C.

Abstract: A device is known for heat treatment of permeable webs of goods with a housing in which at least one screen roller is mounted and a pumping device is associated endwise with the roller, said pumping device drawing a processing medium in the formal of a vapor and/or gas out of the screen roller, with the through-flow area of the roller, in other words the working width of the screen roller, being capable of being determined by a width-adjusting device on the screen roller. A screen roller of this kind is improved according to the invention ifa) at least in the area covered by the web of goods, it has two coaxially mounted permeable screen roller jackets located with a distance between them,b) a width-adjusting device is provided between the outer and inner screen roller jackets, said devicec) being adjustable by a spindle on the axis of the screen roller, andd) the inner screen roller jacket is made permeable only in the area that corresponds to the minimum working width of the roller.

Abstract: A method and device effect controlled uniform temperature drying of a wet web, such as a paper web substantially immediately after formation in a paper machine, without damaging the supporting fabric carrying the web. The web has a central region and first and second border regions. The wet web to be dried is conveyed on a conventional supporting fabric/wire in a first direction generally parallel to the web border regions, and in a hood drying air is blown against the web from the opposite side thereof as the supporting fabric so that the drying air picks up moisture and becomes moistened air. The moistened air is discharged from the volume adjacent the hood, for example is discharged from at least one hood positioned at and encompassing an impingement surface over which the web and supporting fabric pass. Air supplied for blowing against the web is heated to raise its ability to retain moisture.

Abstract: An arrangement for impingement drying and/or through-drying of a paper or material web in which the web is dried by blowing hot air and/or superheated steam from an impingement drying and/or through-drying dryer in a direction substantially perpendicular to the web, and the web runs on support of a wire or equivalent past the dryer. In the area of the dryer, the web and wire are supported from the opposite side of the wire, opposite in relation to the web, by blowings produced from one or more vacuum blow boxes substantially across the entire width of the web. The outlet direction of the blowings may be substantially the same as the running direction of the drying wire and as such, steam and/or air is/are ejected out of the space between the drying wire and the wall placed in connection with the blow boxes that produce the blowings.

Abstract: Method for one of drying and cooling a web in which a web is passed over an arcuate circumference of a blow device, a gas is directed from an interior of the blow device at the web through first openings formed in a mantle of the device to form a support zone between the mantle and the web, and moistened exhaust gas is drawn from the support zone into the interior of the blow device through second openings formed in the mantle. A revolving edge support is arranged at each end of the blow device to support the web during the passage of the web over the circumference of the blow device, the edge supports being separate from the blow device, and the edge supports include one of interior circumferential and friction surfaces to seal the support zone.

Abstract: The invention describes a device for through-flow continuous processing of textiles, nonwovens, or paper in web form with a gaseous processing medium circulated in the device. The material rests on the outside of a permeable drum subjected to suction, said drum having bottoms on the ends, namely a sieve-type or perforated covering that rests on the drum structure. For this purpose, sheet metal strips firmly connected with the bottoms extend from one bottom to the other between the bottoms of the drum, with the widths of the strips extending in the radial direction. These sheet metal strips are secured over their entire radially aligned height firmly but releasably to the corresponding bottoms by means of the clamping structure.

Abstract: A screen drum design is known whose drum jacket consists of sheet metal strips running axially and whose width extends in the radial direction. These sheet metal strips must be permanently connected with the endwise bottoms to produce the drum jacket. According to the invention, this connection is made movable. For this purpose, an articulated ring (32) is used that consists of a number of connecting arms (13) mounted pivotably, said arms being connected with articulation at their free ends either with sheet metal strip structure (13, 14) or with bottoms (11, 12) that are located at a distance from the ends of sheet metal strips (13). In this way, movement is always possible between the drum jacket and bottoms (11, 12) to compensate for dimensional changes as a result of temperature fluctuations.

Abstract: A process and an apparatus for removing water from a fibrous web are disclosed. The process comprises providing a fibrous web having a moisture content from about 10% to about 90%; providing an oscillatory flow-reversing impingement gas having frequency of from 15 Hz to 1500 Hz; providing a gas-distributing system comprising a plurality of discharge outlets designed to emit the oscillatory flow-reversing impingement gas onto the web; and impinging the oscillatory flow-reversing gas onto the web through the plurality of discharge outlets, thereby removing moisture from the web. The apparatus comprises a web support designed to receive a fibrous web thereon and to carry it in a machine direction; at least one pulse generator designed to produce oscillatory flow-reversing air or gas; and at least one gas-distributing system in fluid communication with the pulse generator for delivering the oscillatory flow-reversing air or gas to the web.

Abstract: A through-air drying apparatus for drying a traveling wet paper web supported on a continuous fabric comprises a dryer roll about which the fabric and web are partially wrapped and which has a foraminous roll face, a supply hood which surrounds the portion of the roll about which the fabric and web are wrapped and which supplies heated air through the fabric and web and through the roll face into the interior of the roll, and an exhaust system for exhausting air from the roll. An axial exhaust passage is formed through at least one head of the roll. An exhaust manifold is connected to the exhaust passage and defines two outlets on opposite sides of the manifold. A pair of movable ducts are sealingly and releasably engaged with the outlets in the opposite sides of the manifold, the ducts being spaced apart on opposite sides of the roll so that an access space is defined between the two ducts for access to the roll and supply hood.

Abstract: A Yankee hood is disclosed for use in drying wet paper webs. The Yankee will provide a manufacturer to operate at supply temperatures above 1000.degree. F. at lower total energy costs and at increased production. All major components, supply fans, flow concentrator, air flow equalization plenum and gas burner are consolidated and are mounted directly on the device to eliminate the need for additional space requirements. The hood assembly includes an internal high impingement air system which is supported on a floating structural support member. The nozzle impingement system which incorporates a plurality of nozzle boxes will cover approximately a 240.degree. wrap of a typical Yankee cylinder which will be decoupled from its main support end plate members to allow for increases in cross-machine expansion. The support structure for the externally located direct drive motor is designed to eliminate hood vibrations and operate above the natural building frequency.

Abstract: A papermaking machine has a heated Extended Nip press following the pressing section. High temperature pressing raises the exit solids out of the press to 55 to 65 percent. The web then enters a high intensity dryer section where the web is pressed onto a dryer roll in intimate contact with the roll where it is dried up to approximately 90 percent solids. A coating on the dryer roll and the Extended Nip backing roll is composed of ceramic, metal and a fluorocarbon to allow the web to be separated from the backing roll and the dryer roll with ease. The dryer roll is internally heated by steam or preferably gas to between 200.degree. F. and 500.degree. F. An aircap positioned over the web on the dryer blows hot air at a temperature of 200-500.degree. F. at a velocity of 15,000 to 30,000 feet per minute onto the web.

Abstract: A method for drying a cellulose web, in particular a moist paper web evincing a dry-state specific surface weight of between 10 and 80 g/m.sup.2 and initially a solids content between 8 and 30% approximately, and including supporting the web on a permeable conveying fabric and having a high-speed flow of hot air pass through the web, is characterized in that the flow of air is generated by a relative negative pressure of 100 to 500 mbars generated underneath the fabric.

Abstract: A steam distribution and condensate recovery system for pulp dryers has a plurality of steam heat exchangers. The system includes a steam feed conduit adjacent one end of each heat exchanger. A condensate conduit is adjacent the one end of each heat exchanger. A first connecting conduit is positioned adjacent the one end of each heat exchanger and connects each heat exchanger to the steam feed conduit. A second connecting conduit is placed adjacent the one end of each heat exchanger and connects each heat exchanger to the condensate conduit. Preferably the connecting conduits includes expansion loops. The expansion loops extend away from heat exchanger and away from access doors adjacent each heat exchanger.

Abstract: Apparatus for drying a web and modifying the moisture profile of the web includes a housing within which is disposed a through air dryer roll supporting a web. A fan located at an end of the roll causes flow of air through the web while the web is on the roll and through openings in the roll into the interior of the roll. The air then flows through a roll end and into the interior of the housing externally of the roll for recirculation back into the roll interior through the web and through the openings in the roll. Heaters heat the flowing air and are used to modify the moisture profile of the web. The apparatus is very compact.

Abstract: In the device disclosed, a paper web is carried on a belt and stabilized by an underpressure produced by a box opposite the roll, the paper web being sucked by the underpressure against the belt. Located in the box, immediately following the underpressure zone, may be a pressure zone which assists to transfer the paper web to the roll. In an alternative embodiment, a fan can be avoided. Instead the air entrained by the rapidly running belt is deflected by a wedge-shaped deflector and passed over a slit to generate an underpressure inside the box.

Abstract: Apparatus and method for drying a wet web and modifying the moisture profile of the web. A plurality of gas burners are located within the interior of a through air dryer hood to variably heat air passing through the hood interior before it contacts a wet web on a through air dryer web support. The flowing air within the hood interior is divided into air flow portions directed toward different incremental width portions of the wet web. The burners are separately controlled to vary the heat of the individual flowing air portions to provide a uniform web moisture profile.

Abstract: The present invention relates to heating systems for drying wet coatings such as printing inks, paint, sealants, etc. applied to a substrate. In particular, the invention relates to a drying system in which a blower having an inlet directs a current of heated gas such as air towards a wet coating on a substrate to dry the coating and wherein the heated air is circulated back to the inlet of the blower once the air impinges the coating on the substrate. The present invention also relates to a drying system in which the substrate is supported about a thermally conductive roll having a plurality of energy emitters disposed within the conductive roll along a length of the conductive roll. The plurality of energy emitters are controlled to selectively emit energy along the length of the conductive roll.

Abstract: A web support foil positioned adjacent to a Yankee dryer above a creping doctor. The foil supports the web as it leaves the dryer. Mounted to the top of the foil is an adjustable air deflector which is positioned tangent to the Yankee dryer. The air deflector blocks air moving along the web. A slotted opening draws air from a leading-edge pocket collecting fibers which are broken loose during the creping action. The web is held against the bottom side of the foil by one or more air jets which are directed over the bottom surface on the foil. The jets of air function as coanda air jets and prevent the web from sticking to the bottom surface of the foil while creating a Bernoulli effect which holds the web against the bottom of the foil.

Abstract: A device for threading a paper web from a dryer section to a finishing device situated after the dryer section in the running direction of the web including a rope threading arrangement. A leader strip is separated from the edge of the paper web in the dryer section and the leader strip is directed between a pair of ropes included in the rope threading arrangement. The leader strip is carried to the finishing device on support of the ropes. To effect the transfer of the leader strip from the drying wire to the rope, at the inlet side of the last drying cylinder in the dryer section, a rope gap is formed out of the ropes and the leader strip, which is supported by the drying wire thereat, is transferred by an air blowing into the rope gap. The leader strip is passed by the ropes over the last drying cylinder to the finishing device.

Abstract: A machine for producing a material web, e.g., a paper or cardboard web, with a dryer section including at least one dryer group having a plurality of dryer cylinders and a plurality of web guide rolls, e.g., suction web guide rolls. At least one web guide roll, and preferably all, may be associated with an external suction box. Further, a jacket of the at least one web guide roll may include a plurality of through openings and at least one groove formed in an outer surface of the jacket. A predetermined number, and preferably all, of the through openings may be coupled with a bottom portion of the at least one groove to enable the external suction box to suction the at least one web guide roll.

Abstract: A paper drying apparatus including a first rotatable drum, wherein the first rotatable drum has an inner perimeter and an outer perimeter and a second rotatable drum having an inner perimeter and an outer perimeter. A fabric sheet for carrying a paper web is provided, wherein the fabric sheet passes around the outer perimeter of the first rotatable drum and proceeds to next pass around the outer perimeter of the second rotatable drum. As the fabric sheet conveys the paper web around the first rotatable drum, a drying air is applied to the paper web in a direction from the inner perimeter of the first rotatable drum toward the outer perimeter of the first rotatable drum, further passing through the paper web. As the fabric sheet and paper web proceed around the second rotatable drum, a drying air is applied to the paper web in a direction from the outer perimeter of the second rotatable drum toward the inner perimeter of the second rotatable drum, further passing through the paper web in a similar direction.

Abstract: The apparatus for drying an electrode plate for a battery has: a support drum of a cylindrical shape having a peripheral face on which a long sheet-like electrode plate for a battery is to be wound, and in which a large number of blow holes for allowing the electrode plate for a battery to run in a levitated manner are formed; external air blowing means which is adjacent to the support drum and which has a blowing port through which air is blown to a surface of the electrode plate for a battery wound on the support drum; and moving means for causing the electrode plate for a battery to run in a longitudinal direction of the electrode plate for a battery. The heat loss is small and the productivity is excellent, and a high-performance battery electrode plate which is free from a crack and a scratch and which has a stable quality can be produced.

Abstract: A method and device for drying a coating on a paper web or equivalent in which the direction of running of the paper web is turned, free of contact, by blowings produced by a turning device and the coating on the paper web is dried free of contact by blowings of drying devices placed at both sides of the paper web. The direction of running of the paper web is turned by drying blowings. The exhaust air of the turning device and drying device, which is placed at the side of the turning device, is removed from direct vicinity of the paper web or equivalent by a common exhaust device. The turning device and drying device are placed under and within a common box construction so that access of the exhaust air into the surrounding space is prevented. The device includes a turning device for turning the running direction of the paper web free of contact and a drying device for contact-free drying of the coating on the paper web.

Abstract: The invention is directed to a drying section of a paper machine for drying a fiber web. The drying section includes a plurality of drying groups, with each drying group having a plurality of heatable drying cylinders and a continuous hold-down belt. The hold-down belt has a longitudinal tension which biases the fiber web against the drying cylinders. The plurality of drying groups include at least one high-pressure group comprising a single-row drying group having one row of drying cylinders and one row of corresponding deflection rolls. The high-pressure group has a corresponding hold-down belt with a longitudinal tension which is at least 10 kN/m.

Abstract: An apparatus for the application of steam onto a paper web has a steam blower box with numerous zone chambers arranged side by side over the web width. The steam blower box is displaceable so that the spacing between it and the web path is adjustable. A steam supply line extends from each zone chamber in the longitudinal direction through the interior of the steam blower box, and from there outward to a support plate. There the clearance between adjacent steam lines is substantially greater than in the interior of the steam blower box. A steam control valve, that is connected via a flexible line to the support plate, is provided for each zone chamber laterally outside the paper-making machine.

Abstract: Apparatus for drying a wet web, such as a wet paper web, includes a through air dryer roll. A rotatable fan member having fan blades is located within the through air dryer roll interior at one end of the through air dryer roll. Rotation of the fan member causes air flow through a web on the through air dryer roll, through openings of the through air dryer roll into the through air dryer roll interior, through the end of the through air dryer roll accommodating the fan member, and through an air flow passageway to the exterior of the through air dryer roll.

Abstract: A device is arranged in the drying section of a papermaking machine for reducing the effects of the tendency of a paper web (4) to adhere to a drying cylinder (1) as it passes from the drying cylinder to a subsequent guide roll (2). In the drying section, the paper web (4), supported by a drying fabric (5), is conducted alternatingly over a plurality of drying cylinders (1) and guide rolls (2). A blow box (6) is arranged in the transition portion (A) and has a wall (7) extending in parallel with the drying fabric (5) so as to form a narrow air gap (8) between the wall and the drying fabric. The blow box (6) comprises nozzle (12) having a slot-shaped opening for ejecting a well-defined air jet (P1) towards the drying fabric (5) away from the air gap (8). The nozzle (12) is directed such that its center plane intersects the circumferential surface of the drying cylinder (1) along a first straight line positioned upstream of a second line, along which the paper web (4) leaves the drying cylinder (1).

Abstract: Apparatus for distributing a heating medium, such as steam or hot air, to a paper web or calendar roll in sheet making machinery includes a removable profile screen to permit easy cleaning and maintenance. The apparatus comprises an elongated chamber to receive steam or hot air from a supply source with a front wall adapted to receive a removable screen. The removable screen is flexible and defines at least a portion of the front wall conforming generally to the shape of the adjacent surface to be heated. The screen member has a plurality of apertures through which the heating medium is forced to heat the surface. The screen is removably mounted to the apparatus by clip members.

Abstract: A steam blast box for applying steam to a web of paper conducted over a roll of a paper machine. The box has a closed steam blast chamber which extends along the roll transverse to the direction of travel of the web and to which steam can be fed. The front wall of the box, which faces the roll, has a plurality of steam outlet openings. A steam propagation space is formed between the front wall of the steam blast box and the roll. For controlling the temperature and/or for regulating the amount of heat transferred to the web of paper in the steam propagation space, an air outlet channel, which extends transverse to the direction of travel of the web and is located at the web inlet end of the steam propagation space, is provided for the admixing of air in the steam. In this way, sensitive separate, zone-wise control of the heating of the paper web can be obtained. The steam propagation space can be cooled zone-wise by feeding air on the inlet side.

Abstract: A device for continuous treatment of sheet material or the the like includes a permeable drum for wet or dry treatment of textile material, paper or other permeably materials of a certain width having a normal perforated sheet metal drum jacket, upon which sheet metal strips extending longitudinally over the length of the drum are welded at a spacing from one another. The sheet metal strips improve the uniform ventilation of the material lying externally on the a screen mesh covering on the edges of the sheet metal strips and in addition increase the resistance of the drum to bulging.

Abstract: A permeable sheet-metal drum for the wet or dry treatment of textile material, paper or other permeable material of a certain width comprises a normal perforated sheet-metal drum body, on which, along the length of the drum body, projecting sheet-metal strips are attached at a distance from one another. The attachment is achieved by means of bolts or rivets which are inserted into a transverse flange of each metal strip which is perforated like the perforations of the drum and extends perpendicular to each of the sheet-metal strips. The sheet-metal strips increase the drum's resistance to denting and improve the uniform ventilation of the textile or like material lying externally on the edges of the sheet-metal strips on a screen mesh covering.

Abstract: An apparatus for drying photo-sensitive material having a transfer path for the photo-sensitive material having at least one curved section, a supply device for supplying hot air to the photo-sensitive material, and a suction duct for sucking the hot air provided inside the curved section. The apparatus further includes turn rollers provided along the inside of the curved section, and a paper guide having an opening for circulating hot air, provided between the adjacent two rollers of the plurality of turn rollers in such a manner as not to contact with the photo-sensitive material. It is possible to dry all the portions of the photo-sensitive material under a uniform condition, while maintaining the transfer characteristics so that no drying irregularity appears; thereby, making it possible to prevent the reduction in the printing quality of the picture due to the drying irregularity.

Abstract: A method and apparatus for cleaning the surface of a backing roll in a coater or a calender roll. The roll is cleaned by injecting steam from a steam injection chamber against the roll surface at a 15.degree. angle counter to the rotational direction of the roll. Steam impinging on the surface performs effective removal of accumulated dirt and the detached dirt is carried away on the web without a deleterious effect on the quality of the web. Steam injected against the roll is vacuumed away from the roll surface via a suction chamber, whereby the cleaning steam is prevented from escaping to the surroundings.

Abstract: An adiabatic saturator receives a sample of exhaust air exiting a yankee dryer hood to determine the humidity of the exhaust air. The humidity is determined by temperature readings of the exhaust air, saturated air exiting the interior of a saturator cell, and water supplied to the saturator cell interior. An air distributor in the saturator cell interior promotes saturation of the exhaust air and a backflush mechanism backflushes the saturator cell interior to keep the water in the cell interior clean.

Abstract: Blistering of a wet paper web upon a yankee dryer drum is controlled by directing compressed dry air toward the wet paper web in the space between a pressure roll external of the yankee dryer hood and the entry opening between the dryer hood and the yankee dryer drum. The flow of compressed air is controlled so that air flow can be modified across the full width of the wet paper web.

Abstract: Apparatus for drying a wet paper web during manufacture of the paper web. The apparatus allows the moisture profile of the web to be carefully controlled and adjusted. The apparatus includes a rotatable dryer drum and a hood partially encompassing the rotatable dryer drum. A plurality of elongated heater nozzle boxes are disposed in the hood interior and extend across the dryer drum in the cross-machine direction, the elongated heater nozzle boxes being arrayed side-by-side in the machine direction. A plurality of gas burners is located in each of the nozzle box interiors and arranged side-by-side along the length of the nozzle box interiors for producing hot combustion gases within the nozzle box interiors of the heater nozzle boxes.

Abstract: One or more nozzle boxes are supported by support walls of a yankee dryer hood. The mounting arrangement serves to maintain the nozzle boxes concentric to the yankee, reduce thermal stresses, and alleviate edge misalignment problems between the nozzle boxes and web cages caused by thermal expansion.

Abstract: A paper web impulse drying apparatus and method. A paper or paperboard web, typically of indefinite length, is treated after issuing from a Fourdrinier or other paper making apparatus by passing it through the nip of a pair of rolls, at least one of which is heated. The rolls both compress the web and raise it to a relatively high temperature. Such treatment enhances certain properties of the web. Web delamination due to flashing of superheated water, after the web leaves the nip, is prevented by both (a) a steam chamber on the exit side of the nip through which the web passes, and (b) heating the web prior to its entrance into the nip. This permits lower roll temperatures to be employed, thereby decreasing the magnitude of the sudden decrease in pressure experienced by the web as it exits from the roll nip. By preheating the sheet and passing it through the steam chamber, the temperature of the heated drying roll or rolls can be decreased to 120.degree.-150.degree. C.

Abstract: Heat protection hood for heated rolls (1) in particular for rapidly running rolls (1) in paper machines which are partly surrounded by the heat protection hood. In this arrangement an outer screen (7) is arranged partly around the roll (1) and is concentric to it. The outer screen (7) and a likewise concentrically extending partition screen (4) present between it and the roll (1) form an inner gap (5) and an outer gap (6). Respective deflection zones (9) for the air flow drawn along by the roll (1) in the inner gap (5) adjoin each of the ends of the partition screen (4). Deflecting units (10, 11) are provided there so as to deflect the recirculating air flow around the ends of the partition screen (4). The invention is intended to substantially reduce heat losses through radiation and convection and offers the possibility of influencing the axial temperature profile of the roll (1).

Abstract: A vacuum roll transfer apparatus is disclosed for drying a web extending through a single tier dryer section of a paper machine. The apparatus includes a rotatable perforate shell having a first and a second end. A stationary duct is disposed within and along the length of the shell between the ends of the shell. The duct is connected to a source of partial vacuum and the shell defines a plurality of holes along the length thereof such that in use of the apparatus, when the duct is connected to the source of partial vacuum, a partial vacuum is generated within a chamber defined between the shell and the duct. A flow restricting arrangement is disposed within the duct for generating a greater vacuum level adjacent to at least one of the ends of the shell for facilitating threading of a tail of the web.

Abstract: In the sieve drum device, a screen cover is not arranged, as customary, horizontally with sieve drums located, for example, in side-by-side relationship, but rather concentrically surrounds the respective sieve drum in the region covered by the material. In order to facilitate cleaning of the screen cover, the cover is swingable swung about a joint arranged on an axis in parallel to the sieve drum axis.

Abstract: A nozzle arrangement in a blow box of a paper machine, comprising one or several nozzles (22a, 22b) placed in connection with the blow box (20) or pipe, through which nozzles a blowing of air can be applied to a moving member in a paper machine placed in their proximity, such as a wire, drying cylinder, guide roll, felt, or the equivalent. The blow box (20) and its nozzles (20a, 20b) are at a certain operational safety distance (C) from the moving member. In connection with the nozzle slots of the nozzles (22a, 22b) or nozzle, a respective nozzle flap (24a, 24b) pivotable around a respective transverse hinge shaft (P) is hinged. The nozzle flaps (24a, 24b) respectively guide the blowing of air (F.sub.a, F.sub.b) to the desired object and if necessary maintain a required difference in pressure.