Abstract: The present invention relates to a process for manufacturing a Yankee cylinder. The process comprises welding the first reinforcement flanges of two workpieces of Yankee cylinder section from inside of the cylinder case, preheating and welding the two workpieces of Yankee cylinder section from outside of the cylinder case, and then removing the first, second reinforcement flanges, radial inner end area of the weld and their surrounding material in the workpieces of the Yankee cylinder section, so that the joint of the two workpieces of Yankee cylinder section is machined to meet the final dimension requirements for the Yankee cylinder inner grooves. The present invention is also related to a workpiece of Yankee cylinder section used in the said process.

Abstract: A dehumidification system includes a desiccant, a primary heat exchanger, a secondary heat exchanger, three fans, and a burner. The first fan generates a carbon dioxide airflow through the primary heat exchanger and the secondary heat exchanger. The burner generates a flame into one end of the primary heat exchanger. The flame increases an amount of carbon dioxide within the carbon dioxide airflow. The second fan generates a reactivation airflow that flows over a portion of the secondary heat exchanger, a portion of the primary heat exchanger, and then through a first portion of the desiccant in order to dry the desiccant. The third fan generates a process airflow that flows through a second portion of the desiccant in order to provide dehumidification to the process airflow.

Abstract: A vented heat pump dryer, comprising: an outer drum, an air-intake drying air duct and an air-exhaust drying air duct for allowing communicating the outer drum with outside respectively. The dryer is also provided with a heat pump system. A condenser of the heat pump system is arranged in the air-intake drying air duct, and an evaporator is arranged in the air-exhaust drying air duct. The air-exhaust drying air duct comprises at least two branches capable of being controlled to open and close. Each branch is provided with a corresponding evaporator. At different drying stage, the dryer makes exhaust air stream flow through different branches independently or at the same time, so that can adjust the working states of the heat pump reasonably and increase the drying efficiency of the dryer.

Abstract: The invention relates to a process for manufacturing a steel Yankee cylinder (1), where the Yankee cylinder (1) is welded together from individual pre- or finish-machined cylinder sections (8, 9, 10). In this case, the individual cylinder sections (8, 9, 10) are not welded together at the manufacturing location of the cylinder sections (8, 9, 10), but at an assembly location away from the manufacturing location, preferably on the works premises of the customer.

Abstract: A printed sheet drying apparatus includes, among other components, a nozzle connected to a heated air supply, and an exhaust chamber connected to the nozzle and to a blower. The nozzle comprises a heated air outlet portion. The heated air outlet portion comprises a multi-planar surface having parallel slot openings tapering away from the printed sheet to prevent saturation at the boundary layer. The exhaust chamber has an exhaust opening that matches the shape of the multi-planar surface, and the exhaust opening is larger than the nozzle and is positioned to form an exhaust periphery gap surrounding a periphery of the nozzle.

Abstract: The invention relates to a device for the flow-through treatment of web-shaped, gas-permeable material, in particular for drying woven or non-woven fabrics, having the following characteristics: a sieving drum (5), which is rotatably supported and which is connected to a vacuum generator and which has a permeable outer circumference, wherein the material web (M) to be treated rotates around part of the outer circumference of the sieving drum (5); a treatment chamber (BH), which accommodates the sieving drum and to which the gas to be treated, preferably heated air, is supplied; inside the treatment chamber (BH), a sieving cover (SD) or corresponding flow-conducting elements, which surround the sieving drum (5) in the area around which the material web (M) is wound and by means of which the gas flowing into the treatment chamber (BH) is conducted in the direction of the sieving drum surface.

Abstract: A device for positioning a drain pipe (6) of a draining system in a drying cylinder (1), the jacket (2) of which has inner circumferential grooves (3) for condensate which is formed as a result of heat transfer, said draining system comprising an outlet means and a plurality of drain pipes which are connected to the outlet means, wherein the draining system removes the condensate from the grooves via the drain pipes and the outlet means, wherein the device has a pipe positioner (14) which is disposed in an end portion (12) of the drain pipe located closest to the outlet means, said pipe positioner comprising a mounting device (15) for mounting the drain pipe onto the outlet means, and a lockable connection (16) that connects the drain pipe to the mounting device (15). According to the invention, the lockable connection is a joint connection, which defines a fulcrum for pivoting of the drainpipe in a plane to enable positioning of the drain pipe relative to the bottom surface of the groove.

Abstract: Method for steam recapture in the drying of a tissue paper web with a cylinder that is fed from a live steam network and with a hot air hood that flows hot air onto the tissue paper web, includes the steps of: removing condensate from the cylinder; compressing the condensate to a first pressure level essentially corresponding to that of the live steam network; heating the condensate by heat exchange with the exhaust air from the hot air hood; vaporizing the condensate; and feeding generated steam into the live steam network.

Abstract: A support apparatus and method is disclosed for supporting a syphon within a rotating cylinder. The apparatus includes a hub which is disposed within the rotating cylinder. The hub has a first and a second end, the hub defining a bore which extends between the ends of the hub for rotatably supporting the syphon. A first, second and third arm extend from the hub, each of the arms extending radially outwardly from the hub. Each of the arms has an inner and an outer extremity. The inner extremities of the arms are disposed adjacent to the hub. Also, the outer extremities of the arms are disposed adjacent to an internal surface of the rotating cylinder such that the arms and the hub support the syphon within the rotating cylinder while permitting rotation of the rotating cylinder relative to the syphon.

Abstract: A system and method for self cleaning an air idler are provided. An air idler non-contactingly guides printable media using a flow of fluid through a porous surface portion. Rotation of the air idler results in rubbing contact with one or more wipers, during which debris is removed from the porous surface portion. A cleaning solution is used to remove ink and/or paper residue from the porous surface portion. The cleaning solution can wet one or more of the wipers. The cleaning solution can circulate through a reservoir disposed in contact with a portion of the air idler.

Abstract: A heat pump module and a drying apparatus having the same are provided. The heat pump module may include a housing, an evaporator provided in the housing that condenses humid air introduced into the housing via evaporation of a refrigerant, a condenser provided in the housing that heats the air having passed through the evaporator via condensation of the refrigerant, and at least one condensed water guide or remover provided in the housing that removes condensed water generated on a surface of the evaporator therefrom.

Abstract: The steel-made Yankee cylinder includes a cylindrical shell (11) joined to two ends (13, 15), to which are fixed respective-support journals (3). The cylindrical shell (11) is joined to the ends through a circumferential weld formed between opposing surfaces of each end and of the cylindrical shell.

Abstract: The object of the invention is an apparatus and a method for improving the detachment of paper (1) from the cylinder of a paper machine in a drying section implemented with a single wire transfer, which drying section comprises means for heating the paper on the drying cylinder (3) and for transporting it onwards on the wire (2) via a hitch roll (8) to the next drying cylinder such that the paper together with the wire in the section between the cylinders is sucked against the wire by means of low pressure. What is essential to the invention is that in order to improve the detachment of the paper (1) an apparatus is installed on the opposite side of the drying wire (2) at the detachment point (7), which apparatus comprises a nozzle (14), with which an air jet (11) is blown against the direction of travel (15) of the drying wire, and a carrying surface (9) such that the air jet (11) ejects secondary air (17) along with it causing an air flow (18) between the planar carrying surface (9) and the drying wire (2).

Abstract: Device and process for producing and treating a fibrous web. The device includes a moistening unit structured and arranged to simultaneously influence a cross machine moisture profile of the web and the curl of the web independently of each other. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

Abstract: Disclosed is an apparatus for drying a fibrous web, in particular a paper web, paperboard web or tissue web, by way of hot air, on which the fibrous web is charged with the supply air for the drying from a supply air chamber and on which exhaust air from the drying operation passes into an exhaust air chamber, whereby the exhaust air from the exhaust air chamber is supplied at least partly to the suction side of a pressure booster and at least a part of the supply air from the pressure side of the pressure booster is supplied to the supply air chamber.

Abstract: A through-air dryer system that diverts the airflow within the through-air dryer during warm up and cool down from the normal airflow during the drying of paper in the papermaking process. During warm up and cool down, a majority of the airflow is supplied to one of the dryer's heads and extracted through the opposite head to reduce thermal stresses. If needed to further reduce thermal stresses, a minority of the airflow is supplied through the dryer's shell.

Abstract: A dryer uses conduits to carry a heating medium, such as steam, to heat the outer surface of the dryer. The volume of steam is successfully reduced to non-explosive levels and the shell need not be designed to prevent an explosion. Conduits may be formed through the shell itself or grooves may be formed on the inner surface of the shell, with the conduits retained within the grooves. Also, the conduits can be placed against the inside surface of the dryer and a material, such as zinc, can be filled in about the conduits. The material serves to both retain the conduits in place and thermally couple the conduits to the dryer to assure efficient heat transfer between the conduits and dryer. These modifications relieve the dryer from the Unfired Pressure Vessel classification to the classification of a piping assembly under ASA code regulations. This results in savings in operation safety, installation cost and operating costs due to the absence of costly inspections.

Abstract: A shoe device secured to a syphon is disclosed for removing condensate from an internal surface of a rotating cylinder. The shoe device includes a shoe portion which is disposed adjacent to the internal surface of the rotating cylinder. The shoe portion defines a passageway having an upstream and a downstream end. The passageway permits a flow there through of the condensate from the internal surface of the rotating cylinder, through the upstream end of the passageway to the downstream end of the passageway. The shoe portion has a first and a second side, a surface extending between the first and second sides of the shoe portion. The surface is disposed adjacent to the internal surface of the cylinder. The shoe portion also has a leading and a trailing end and a face extending between the leading and trailing ends of the shoe portion. A clamp is secured to a distal end of the syphon and is connected to the shoe portion for clamping the shoe portion to the syphon.

Abstract: Web stabilizer particularly for one-sided flotation of a running web. The device includes two discharge slots which allow for increased draw down force, which flattens machine direction wrinkles in a floating web. There is a primary discharge slot and a second discharge slot spaced from and stepped down from the primary discharge slot, a first web support surface between the primary discharge slot and the secondary discharge slot, and a second web support surface downstream of the secondary discharge slot in the direction of web travel. An integral blower provides a supply of air that is uniformly distributed to the primary and secondary slots. Air discharged from the primary slot is gathered into the air stream of the secondary slot and creates an increased air cushion to provide greater support to the web and thereby remove machine direction web wrinkles caused by higher tension in light weight webs.

Abstract: A drier installation (1) for drying web (2), more particularly paper, which installation is provided for drying a maximum web width, the installation (1) comprises gas-heated radiant elements (3) for radiating the web, arranged according to at least one row (4) stretching out in the transversal (5) direction over the substantially entire maximum web width. The installation (1) comprises at least a transversal convective system (7, 36) equipped with suction and blowing devices (8) for sucking at least part of the combustion products produced by the radiant elements (3) by means of a suction duct (13) and for blowing this pa o the combustion products towards the web (2) by means of a blowing duct (14). Both suction (13) and blowing (14) ducts stretch out in the transversal (5) direction of the web (2).

Abstract: A dual-purpose, cooling/drying apparatus comprising a rotatable cooling/drying cylinder wherein air, steam, and water supplied from sources external of the cooling/drying cylinder are selectively introducible into and removable from a space defined inside the cylinder. The apparatus includes a first flow path through which the water is selectively introducible into the cylinder space, and a second, separate flow path through which either of the air and steam are selectively introducible into the cylinder space. The apparatus is characterized by a cooling mode, in which the water and air are selectively introducible into the cylinder space through the first and second flow paths, respectively, and a drying mode, wherein the steam is selectively introducible into the cylinder space through the second flow path.

Abstract: A paper machine configured as a swing machine capable of producing both light and heavy grades providing a Yankee hood split into a wet end half and a dry end half, at least one hood half being a flex-hood half wherein the supply for that half is capable of being run with either combustion heat or recycled heat and is capable of either recirculating the exhaust from the hood or discharging it to the atmosphere. The heater for the flex-hood half comprises both a primary combustion heat source and an indirect heat source capable of extracting by-product heat from another operation. The exhaust system for the flex hood half is capable of being run in either a straight through mode or in a recirculating mode.

Abstract: A device for continuous drying of a pulp web, particularly a tissue web, with a drying drum (1) and an air circulating system, where the drying drum (1) has a cylindrical shell (9) designed as a honeycombed body with an annular, flexible transition profile (13) at the edges of the shell and connected to the end covers.

Abstract: There is described a method and apparatus for applying steam from a steam source to a moving web to thereby improve the smoothness and gloss of the web. A housing has at least one cooling chamber upstream and at least one steam chamber downstream. The cooling air in the cooling chamber is used to cool the web before steam is applied to the web from the steam chamber. This allows a sufficient volume of steam to be delivered to the web to thereby raise its moisture content to a desired level to thus achieve optimized calendering of the web.

Abstract: This device comprises a drum having a lateral surface through which fluid can pass, and two flexible belts (2) which pass over the lateral surface of the drum (1) at a distance from one another, each of them on an idle guide roller (3) of its own. Each roller (3) is mounted so as to pivot about a vertical axis (7).

Abstract: A dryer uses conduits to carry a heating medium, such as steam, to heat the outer surface of the dryer. The volume of steam is successfully reduced to non-explosive levels and the shell need not be designed to prevent an explosion. Conduits may be formed through the shell itself or grooves may be formed on the inner surface of the shell, with the conduits retained within the grooves. Also, the conduits can be placed against the inside surface of the dryer and a material, such as zinc, can be filled in about the conduits. The material serves to both retain the conduits in place and thermally couple the conduits to the dryer to assure efficient heat transfer between the conduits and dryer. These modifications relieve the dryer from the Unfired Pressure Vessel classification to the classification of a piping assembly under ASA code regulations. This results in savings in operation safety, installation cost and operating costs due to the absence of costly inspections.

Abstract: A steam blower box unit having a steam blower box for applying steam to a passing material web, especially a paper or board web, and having a withdrawal device at least partly integrated in the steam blower box. The steam blower box, located opposite the material web in an operating position, can be moved out of its operating position laterally via the withdrawal device, that is to say generally transversely with respect to the web running direction, and can be moved into this operating position again from its lateral position. In this case, preferably the entire steam blower box can be moved appropriately via the withdrawal device.

Abstract: To minimize the heat energy required for supplying dry air. A dry air-supplying apparatus 1 comprises a dry air-supplying air path 6 for supplying air from the surroundings that has been heated as dry air and a discharge air path 7 for discharging the moist air to the surroundings after the drying operation by the supplied dry air. Thus, the dry air-supplying air path draws in surrounding air and provides heat-exchanges by a heat exchanger 13 with the air in the discharge air path, this heat-exchanged air is heated by a radiator 14 and is supplied as dry air; while the discharge air path provides heat-exchanges, by the heat exchanger, the moist air after the drying operation with the air in the dry air-supplying air path, cools and dehumidifies the air that has been heat-exchanged by a cooler, and discharges it.

Abstract: An apparatus for dewatering a fiber web in a paper machine includes a heated drying surface, a permeable fabric carrying the fiber web, and a condensing region adjacent a portion of the permeable fabric on a side opposite the fiber web. The fiber web is interposed between and contacts each of the heated drying surface and the permeable fabric. The condensation region has: a) a temperature which is less than a temperature of the permeable fabric; and/or b) a pressure which is greater than an ambient pressure.

Abstract: There is described a method and apparatus for applying steam from a steam source to a moving web to thereby improve the smoothness and gloss of the web. A housing has at least one cooling chamber upstream and at least one steam chamber downstream. The cooling air in the cooling chamber is used to cool the web before steam is applied to the web from the steam chamber. This allows a sufficient volume of steam to be delivered to the web to thereby raise its moisture content to a desired level to thus achieve optimized calendering of the web.

Abstract: A through-air device includes a permeable roll having a hollow interior and mounted for rotation about a longitudinal axis. At least one divider is located in the hollow interior so as to define a plurality of roll channels within the roll, the roll channels being positioned side-by-side along the longitudinal axis. A first housing bounds a first portion of the roll, and a second housing bounds a second portion of the roll. At least one partition is located in the second housing so as to define a plurality of housing channels within the second housing. Each one of the housing channels is aligned with a corresponding one of the roll channels. The device further includes structure for individually controlling airflow through each pair of corresponding roll channels and housing channels.

Abstract: An air processing cylinder useful in drying, curing, thermal bonding, cooling, and web transferring materials such as fabrics, papers, and the like. Air is exhausted out of the cylinder surface through a plurality of conduits equipped with distribution means for profiling the flow of air. The drying cylinder further includes a duct network on its outer shell for exhausting air out of one axial area only or, alternatively, the drying cylinder may contain multiple duct networks for exhausting air out of several axial areas, each having its own flow characteristics.

Abstract: An apparatus is disclosed for increasing a transfer of thermal energy through an inner surface of a hollow cylindrical dryer of a papermaking machine to a peripheral outer surface of the dryer. The apparatus includes a plurality of bars of rectangular cross-sectional configuration, each of the bars extending axially within the dryer. The bars are disposed spaced and parallel relative to each other with each of the bars being urged outwardly against the inner surface of the dryer. Also, each of the bars defines an axially extending enclosure.

Abstract: A thermal transfer roller includes a first end chamber in communication with a source of thermal transfer fluid, an annulus for receiving the fluid and facilitating thermal transfer to a substrate, and a second end chamber in communication with the annulus for receiving the spent thermal transfer fluid. At least one end chamber includes a plurality of channels, each channel having a wider end approaching the annulus and a narrower end away from the annulus. Preferably, the channels are present in both end chambers. The channels substantially reduce angular flow of the fluid caused by rotation of the roller, and help stabilize and maintain desired fluid volumes flowing through the roller as its velocity is increased.

Abstract: An apparatus for drying a travelling wet fibrous web is provided which comprises a rotating air-permeable drum. The drum is at least partially surrounded by a hood which has an interior space for receiving a flow of air and directing the flow of air through a permeable inner wall towards the outer surface of the drum. At least a portion of the hood is divided into individual sections in a cross-machine direction. Apparatus is provided for supplying a flow of drying air at a first temperature to the hood, and for supplying profiling air at a selected different temperature different from the first temperature to at least one of the individual sections.

Abstract: A steam blower box for the application of steam on a material web, particularly paper, which travels past the steam blower box includes a housing wall which faces the material web and extends transversely of the web travel direction. A plurality of steam outlet openings are arranged in the housing wall. The steam outlet openings are arranged in at least two separate groups, wherein at least one section which is free of steam application is provided between two adjacent groups, and wherein the air entrained by the material web is discharged through this section.

Abstract: A method for increasing the drying capacity of a steam group (6) in a drying section of a pulp or paper machine. According to the method, a main steam flow (3) having a first steam pressure is fed to the steam group (6), the main steam flow (3) is conducted to at least one thermocompressor (9), which is driven by motive steam (4) having a second steam pressure, which is driven by motive steam (4) having a second steam pressure, which is higher than the first steam pressure, and the output steam (13) of said at least one thermocompressor (9) is fed to the steam group (6), the steam pressure of the steam that is fed to the steam group (6) being higher than the first steam pressure.

Abstract: A method and an apparatus for arranging exhaust air and supply air in a drying section covered with a hood (14) in a paper machine, having drying cylinders (10) or the like and devices operating by negative and positive pressure. The exhaust air from the devices operating by negative pressure, such as suction rolls (20) and suction boxes is supplied out from the drying section via a first heat recovery tower (22). Substitute air is supplied via this first heat recovery tower to the runnability components (38) operating by positive pressure in the drying section. Substitute air can be additionally supplied via a second separate heat recovery tower (22′) to devices (40, 42) supplying heating air and/or ventilation air. The main portion of the exhaust air from the air space of the hood is supplied via this second heat recovery tower and out from the drying section.

Abstract: There is described a method and apparatus for applying steam from a steam source to a moving web to thereby improve the smoothness and gloss of the web. A housing has at least one cooling chamber upstream and at least one steam chamber downstream. The cooling air in the cooling chamber is used to cool the web before steam is applied to the web from the steam chamber. This allows a sufficient volume of steam to be delivered to the web to thereby raise its moisture content to a desired level to thus achieve optimized calendering of the web.

Abstract: A rotary cooling roller includes outer and inner cylinders, two end plates fixed to both ends of the outer cylinder, and a supporting shaft protruding from the end plates. A cylindrical space, provided between the outer and the inner cylinders, communicates with the inner space of the inner cylinder via through-holes formed in the inner cylinder. A coolant contained is allowed to flow back and forth between the cylindrical space and the inner space of the inner cylinder. Ring-shaped spacers are provided in the cylindrical space for passing an external force exerted on the outer cylinder to the inner cylinder.

Abstract: A method and an apparatus for arranging exhaust air and supply air in a drying section covered with a hood (14) in a paper machine, having drying cylinders (10) or the like and devices operating by negative and positive pressure. The exhaust air from the devices operating by negative pressure, such as suction rolls (20) and suction boxes is supplied out from the drying section via a first heat recovery tower (22). Substitute air is supplied via this first heat recovery tower to the runability components (38) operating by positive pressure in the drying section. Substitute air can be additionally supplied via a second separate heat recovery tower (22′) to devices (40, 42) supplying heating air and/or ventilation air. The main portion of the exhaust air from the air space of the hood is supplied via this second heat recovery tower and out from the drying section.

Abstract: The invention relates to a method and a drying section for dewatering a fibrous web (9), the drying section preferably being intended to dry fibrous webs in a paper machine, and the drying section comprising a number of drying cylinders (8), by which an inlet and outlet nip are formed when running the fibrous web, and the drying section comprising drying devices for decreasing the moisture content of the fibrous web, the drying devices comprising a blow device for blowing air in the proximity of the surface of the fibrous web.

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 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: The invention concerns a method and a device in the dryer section of a paper/board machine. In the dryer section a normal single-wire draw is applied at least partly, in which method the web (W) is passed through the dryer group on support of a drying wire (H). The drying wire (H) presses the web (W) on the drying cylinders (Kn, Kn+1 . . . ) against the heated cylinder faces, and on the reversing cylinders or rolls (Sn, Sn+1 . . . ) between the drying cylinders (10) the web (W) remains at the side of the outside curve. There is one integrated device, through which a support suction and/or blowing is produced in order to improve the runability of the web (W) and to keep the web (W) in contact with the face of the wire, and through which same device, additionally, impingement blowing is produced in order to dry the web (W) and/or to control its tendency of curling.

Abstract: An apparatus for processing a continuous web having a first side and a second side includes a plurality of rollers are arranged for cooperative rotation. The plurality of rollers are positioned to define a corresponding plurality of nips. The continuous web is processed through at least two of the plurality of nips. At least a first roller of the plurality of rollers has at least one void formed in the cylindrical middle surface. First and second sealing panels engage first and second circular ends of each of the plurality of rollers and define a chamber. A first pressure source is fluidly coupled to the chamber to pressurize the chamber. A membrane is positioned adjacent the first side of the continuous web to separate the continuous web from direct communication with the chamber.

Abstract: A steam box in a paper machine, the steam box including a main steam zone and at least one side steam zone through which steam is blown to a paper web. The side steam zone is placed in a side section of the steam box and arranged to form a curtain in order to prevent air from entering between the steam box and the paper web from outside the steam box and/or to prevent steam from exiting between the steam box and the paper web. Steam is supplied to the side steam zone from a steam chamber through a side steam zone valve arranged inside the steam box.

Abstract: A steam box includes a elongated steam-distribution chamber, regulator chambers set in a row next to the elongated steam-distribution chamber and covered on one side with a continuous perforated screen. Operating devices distribute the steam from the distribution chamber to each regulator chamber. The steam box is intended to feed steam through the perforated screen to the web, to heat it according to a desired profile. The perforated screen is secured along one long edge to hinge members and along the opposite edge to locking members and is arranged to be able to be opened, to permit access to the regulator chambers.

Abstract: Soft roll that may include a roll tube having an outside surface and a sealed interior space, and an elastic coating provided on the outside surface. The sealed interior space may include a vaporizable liquid and a heat exchanger for cooling heat generated in the roll during use. The sealed interior space may be gas-tight and the temperature of the heat exchanger may be set to condense vaporized liquid.

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: A method and apparatus for drying a fiber web, in which the fiber web is dried between two tight bands moving in the same direction and turning around turning rolls. The first band is heated and the second band is cooled by a cooling chamber. The cooling chamber includes at least one cooling element and the cooling element includes at least one inlet chamber and at least one outlet chamber. The fiber web is arranged to run through a drying zone, with at least one felt or wire, such that the fiber web is in contact with the surface of the first, heated band and the felt or wire is between the fiber web and the second, cooled band. The pressure of the cooling element is balanced by a pressure balancing means, and the second band is provided with a hydraulic bearing for allowing the band to slide evenly and with little friction on the cooling chamber.