SE2230068A1

SE2230068A1 - A machine for producing a fibrous web

Info

Publication number: SE2230068A1
Application number: SE2230068A
Authority: SE
Inventors: Anders Ottosson; Bruno Tremblay; Mikhail Y Shekhter; Toni Räty; Viktor Bergström
Original assignee: Valmet Oy
Priority date: 2022-03-10
Filing date: 2022-03-10
Publication date: 2022-11-15

Abstract

The invention relates to a machine (1) for producing a fibrous web, such as for tissue, for example paper tissue, comprisinga forming section (2) adapted to form a web (3) from a furnish,and a through air drying (TAD) section (4), comprising a TAD cylinder (401) with a peripheral structure having a plurality of openings, the TAD section further comprising a TAD fabric (402) forming by means of a plurality of rollers an endless loop which partially extends around the TAD cylinder (401),the machine being arranged to transfer the web (3) from the forming section (2) to the TAD fabric (402), whereby the web (3) is brought in contact with the TAD fabric (402) at a transfer station (403) located upstream of the TAD cylinder (401), the machine being arranged to establish a pressure difference externally and internally of the TAD cylinder (401), so that air is drawn through the web (3), the TAD fabric (402), and the peripheral structure of the TAD cylinder (401), wherein the machine is arranged to apply to the web (3) a heated fluid downstream of the transfer station (403) and upstream of the TAD cylinder (401).

Description

A MACHINE FOR PRODUCING A FIBROUS WEB TECHNICAL FIELD The invention relates to a machine for producing a fibrous Web, a through air drying section for a machine for producing a fibrous Web, and a method for producing a ﬁbrous Web.

BACKGROUND In tissue manufacturing technology, through air diying (TAD) has become a Well-established process. A typical TAI) section of a machine for producing a fibrous Web cornprises a TAD cylinder With a peripheral structure having a plurality of openings, and a TAD fabric forming an endless loop Which partially extends around the TAD cylinder. The machine is arranged to establish a pressure difference externally and internally of the TAD cylinder, so that air is draWn through the Web, the TAD fabric, and the peripheral structure of the TAD cylinder. Thereby, the Web is deWatered and dried by non-coinpressive means, thereby avoiding a compaction of the Web.

WO20l7l39l24Al mentions increasing the mobility of papermaking fibers. The document discloses a method including forrning a nascent Web from an aqueous solution of papermakiiig fibers, deWatering the nascent Web to form a deWatered Web, moving the deWatered Web on a transfer surface, and transferring the deWatered Web from the transfer surface to a molding roll. The Web is then transferred from the molding roll to a TAD fabric Which carries the Web and passes around through-air dryers. A steam shower directs steam toWard the Web on the inolding roll and Vacuum is used to draW the steam though the Web, thus heating the Web.

There is neveitheless a desire to further increase the productivity of machines for producing ﬁbrous Webs, Which machines comprise TAD cylinders, and/or reduce the energy consumption of such machines.

SUMMARY An object of the invention is to increase the productivity of machines for producing fibrous Webs, Which machines comprise TAD cylinders, and/or reduce the energy consumption of such machines.

The object is reached With a machine for producing a ﬁbrous Web, such as tissue, for example paper tissue, comprising - a forming section adapted to form a Web from a furnisli, - and a through air drying (TAD) section, comprising a TAD cylinder With a peripheral structure having a plurality of openings, the TAD section further comprising a TAD fabric forrning by means ofa plurality of rollers an endless loop Which partially extends around the TAD cylinder, - the machine being arranged to transfer the Web from the forming section to the TAD fabric, Whereby the Web is brought in contact With the TAD fabric at a transfer station located upstream of the TAD cylinder, - the machine being arranged to establish a pressure difference externally and internally of the TAD cylinder, so that air is draWn through the Web, the TAD fabric, and the peripheral structure of the TAD cylinder, - Wherein the machine is arranged to apply to the Web heated ﬂuid downstream of the transfer station and upstream of the TAD cylinder.

The invention thus provides for the machine to be arranged to apply to the Web heated fluid doWnstream of the transfer station and upstream of the TAD cylinder. The heated fluid may be steam and/or heated air. The heated air may be moist air.

The heated fluid applied doWnstream of the transfer station and upstream of the TAD cylinder may preheat the moisture in the Web before reaching the TAD cylinder. Thereby moisture in the Web may be less viscous and thereby more easily removed during the following TAD section. More specifically, the increased temperature caused by the heated ﬂuid application may provide for both the surface tension and the viscosity of the Water in the Web to decrease.

Thereby, the Water flow on the TAD cylinder may increase.

By facilitating the Water floW on the TAD cylinder, less energy may be used in the TAD section. Alternatively, the deWatering improvement can be used to increase the production. In addition, the applied heated fluid may be of a relatively loW temperature and loW value heat, While suppressing the need for high temperature process heat. This Will effectively reduce the need for use of fossil primary energy sources.

The application of the heated fluid doWnstream of the transfer station and upstream of the TAD cylinder, ensures that the effect of the heated fluid on the Web remains in the TAD section. To transfer the Web to the TAD fabric, a suction box or similar Will be needed. An application of heated ﬂuid upstrearn of the transfer station Will result in the Web getting cooled by the suction box. Thereby, the effect of the heated ﬂuid application in the TAD section Will be at least partly lost.

Further, the application of the heated ﬂuid doWnstream of the transfer station means that the ﬂuid application may be located close to the TAD cylinder. This further ensures that the temperature increase obtained by the heated fluid application is retained When the Web reaches the TAD cylinder.

In addition, the application of the heated fluid doWnstream of the transfer station, means that the Web may be transferred from a carrier in the forming section to the TAD fabric, Without any intermediate carrier, While the benefits of the heated fluid application are fully secured. Such a minimization of the number of transfers of the Web is beneficial to the production result.

Further, the application of the heated ﬂuid doWnstream of the transfer station may allow a higher Web Water content after the forming section. This in turn Will alloW an increased Web speed through the forming section, Whereby production is increased.

In addition, embodiments of the invention may have a positive effect on reducing Web moisture Variations. This may be the case even if the heated ﬂuid is applied evenly over the Web Width.

Further, embodiments of the invention may have a positive effect on sheet structuring is, potentially improving sheet bulk.

Preferably, the heated fluid comprises steam and/ or moist air. Thus, the machine may be arranged to apply to steam and/or moist air doWnstream of the transfer station and upstream of the TAD cylinder. By using steam and/or moist air, heat applied to the Web Will have a high energy content. Further, lf the heated fluid is steam and/or moist air, condensation may occur on the Web. This is a very effective mechanism for heat transfer. Moreover, heat may be transferred by means of forced convection, Which is another very effective mechanism for transferring heat.

Preferably, the machine comprises an ejector located on a first side of the TAD fabric, by means of Which ejector the application to the Web of the heated fluid is provided. The ejector may be arranged to apply the heated fluid evenly over the Web Width. This alloWs for an ejector With a simple construction, e. g. compared to knoWn steam or blow boxes With a profiling capability to differentiate the amount of heat supplied in the lateral direction of the Web.

Preferably, the machine comprises a vacuum device adapted to present a reduced pressure on a second side of the TAD fabric, opposite to the location of the ejector. The vacuum device may be located on the second side of the TAD fabric. Thereby, a sub-atmospheric pressure of the vacuum device Will draw the heated ﬂuid into the Web. Further, the vacuum device Will draw the heated fluid through the Web and the TAD fabric. Thereby, the heat is transfeired to the Web and the TAD fabric. The heat transferred to the Web Will make the moisture in the Web less viscous and thereby more easily removed by the vacuum device. Further, the vacuum device may provide a suction deWatering effect. This deWatering effect may be used to further reduce the energy consumption of the TAD section. The inventors estimate that in embodiments Where the ejector, located on a first side of the TAD fabric, applies heated fluid doWnstream of the transfer station and upstream of the TAD cylinder, and the vacuum device presents a reduced pressure on a second side of the TAD fabric, a combined effect of the suction deWatering and the preheating of the Web Will lead to a TAD energy reduction of 5 to 10%, i.e. 200 to 350 kWh/ton.

Preferably, the vacuum device is adapted to mold the Web into the TAD fabric. Thereby, the TAD fabric may have a three-dimensional structure. This Will increase the amount of Web molding that occurs on the TAD fabric. This Will increase the bulk of the Web.

The vacuum device may be iion-rotatiorial. For example, the vacuum device may be provided in the form of a so-called molding box. Thereby, there is no need for any motor etc. to rotate the vacuum device. However, in some embodiments, the vacuum device comprises a roll. The roll could be a molding roll. Thereby, the time of contact of the web with the vacuum device may be longer than in a case of a iion-rotational vacuum device. Thereby, the effect of the vacuum device may be improved. ln some embodiments, the machine comprises a molding device located downstream of the transfer station and upstream of the TAD cylinder, and adapted to mold the web into the TAD fabric, wherein the ejector is located downstream of the molding device. Thereby, the molding function may be separate from the heated fluid application function. Thereby, the vacuum device may be dedicated for the heated ﬂuid application. The position location downstream of the molding device may ensure a short distance between the heated fluid application and the TAD cylinder. Thereby, a high retention of the applied heat may be secured. lt should be noted however, that is some embodiments, the ejector is located upstream of the molding device.

Preferably, the heated fluid applied to the web is a Waste product of another process. This will further reduce the need for energy in the TAD section. This may lead to lower emissions. Also, the waste product, e. g. steam, may be available cheaply. Thus, cost savings may be provided. In other words, the heated fluid application may utilize excess heat providing inexpensive thermal energy to increase the temperature of the web and the TAD fabric. ln some embodiments, the machine is arranged so that the heated fluid applied to the web is provided by means of the air drawn through the web, the TAD fabric. and the peripheral structure of the TAD cylinder. For example, the heated fluid applied to the web may be taken from an exhaust of an air system for the TAD section. This provides an effective use of energy for the TAD process as well as for the heated fluid application.

In some embodiments, the machine is arranged so that the heated fluid applied to the Web is provided by means of steam from a biomass combustion process. The biomass combustion may be provided for a boiler.

In some embodiments, Wherein the machine coinprises a yankee dryer doWnstream of the TAD section, the machine is arranged so that the heated ﬂuid applied to the Web is provided by means of an exhaust of a hood of the yankee dryer.

In some embodiments, Wherein the machine comprises a vacuum bloWer arranged to provide a pressure gradient across the Web in the forming section to remove Water from the Web, the machine is arranged so that the heated fluid applied to the Web is provided from an exhaust from the vacuum bloWer.

The object is also reached With a through air drying (TAD) section for a machine for producing a fibrous Web, such as tissue, for example paper tissue, comprising - a TAD cylinder With a peripheral structure having a plurality of openings, and a TAD fabric forming by means of a plurality of rollers an endless loop Which partially extends around the TAD cylinder, - the TAD section being arranged to receive a Web from a forming section of the paper machine, Whereby the Web is brought in contact With the TAD fabric at a transfer station located upstream of the TAD cylinder, - the TAD section being arranged to establish a pressure difference externally and internally of the TAD cylinder, so that air is draWn through the Web, the TAD fabric, and the peripheral structure of the TAD cylinder, - Wherein the TAD section is arranged to apply to the Web heated ﬂuid doWnstream of the transfer station and upstream of the TAD cylinder.

The TAD section may present any of the features presented by TAD section of the machine for producing a fibrous Web disclosed above. As understood, the forming section may be adapted to form the Web from a fumish.

The object is also reached With a method for producing a fibrous Web, such as tissue, for example paper tissue, comprising - forming a Web from a furnish, - transferring the formed Web to a TAD fabric, Which forms by means of a plurality of rollers an endless loop Which partially extends around a TAD cylinder With a peripheral structure having a plurality of openings, Whereby the Web is brought in contact With the TAD fabric at a transfer station located upstream of the TAD cylinder, - establishing a pressure difference externally and intemally of the TAD cylinder, so that air is draWn through the Web, the TAD fabric, and the peripheral structure of the TAD cylinder, - Wherein the method comprises applying to the Web heated fluid doWnstreani of the transfer station and upstream of the TAD cylinder.

DESCRIPTION OF THE DRAWINGS BeloW embodiments of the invention Will be described With reference to the draWings, in Which fig. l shoWs schematically a machine for producing a fibrous Web, fig. 2 shows steps in a method for producing a fibrous Web, fig. 3 shoWs a machine for producing a ﬁbrous Web according to an alternative embodiment of the invention, fig. 4 shoWs a machine for producing a fibrous Web according to a further embodiment of the invention, fig. 5 shows a part of the machine in fig. l and a system for supplying heated fluid to be applied to a Web in the inachiiie, fig. 6 shoWs a part of a machine for producing a fibrous Web, and an alternative system for supplying heated fluid to be applied to a Web in the machine, and fig. 7 shoWs a part of a machine for producing a fibrous Web, and another alternative system for supplying heated ﬂuid to be applied to a Web in the machine.

DETAILED DESCRIPTION OF EMBODIMENTS Pig. l shoWs a machine l for producing a fibrous Web. The fibrous Web produced by the machine may be for example used for paper tissue, such as cloth or toWel.

The machine comprises a forming section 2 adapted to forrn a Web 3 from a furnish. A first forming fabric 204 and a second forrning fabric 206 partly encircles a forrning roll 208. The furnish is introduced through a headbox 202. The furnish is introduced between the first forrning fabric 204 and the second forming fabric 206. After passing the forrning roll 208, the ﬁrst forming fabric 204 and the second forming fabric 206 diverge. The second forming fabric 206 and the Web 3 pass through a dewatering region 212. ln the deWatering region 212 suction boxes 214 remove moisture from the Web 3. Also, for the deWatering, hot air may be used in the deWatering region 212.

The machine further comprises a through air drying section 4. Through air drying is usually abbreviated TAD. The TAD section 4 comprises a TAD cylinder 401. The TAD cylinder has a peripheral structure having a plurality of openings. The openings of the peripheral structure may extend in the radial direction of the TAD cylinder. The peripheral structure of the TAD cylinder may be of a honeycomb design. The TAD section 4 further comprises a TAD fabric 402. The TAD fabric 402 forms by means of a plurality of rollers an endless loop Which partially eXtends around the TAD cylinder 401.

The machine is arranged to transfer the Web 3 from the forrning section 2 to the TAD fabric 402. More specifrcally, the machine is arranged to transfer the Web 3 from the second forming fabric 2()6 to the TAD fabric 4()2. Thereby the Web 3 is brought in contact With the TAD fabric 402. The transfer station 403 may comprise a shoe (not shown) that presses the TAD fabric 402 against the second forming fabric 206. The transfer station 403 may comprise a suction box 403” to separate the Web 3 from the second forniirig fabric 206. In some embodiments, the transfer station 403 cornprises a vacuum shoe that applies a sub- atmospheric pressure to assist in the transfer of the Web 3 to the TAD fabric 402.

The TAD cylinder 4()1 is partly surrounded by a TAD hood 407. The machine is arranged to establish a pressure difference externally and internally of the TAD cylinder 401, so that air is draWn through the Web 3, the TAD fabric 4()2, and the peripheral structure of the TAD cylinder 401. Tlius, air is draWn into the TAD cylinder 401. The pressure difference is provided by a TAD air system, e. g. as the one exemplifred beloW. A sub-atrnospheric pressure is established Within the TAD cylinder 401 by one or more circulation fans in the TAD air system. The air is heated before it is supplied to the TAD hood 407. From inside the TAD hood 407 the air is draWn through the Web 3, the TAD fabric 402, and the peripheral structure of the TAD cylinder 401. Thereby, the air comes in contact With Water in the Web 3, and moisture is transferred from the Web to the air.

The machine further comprises a yankee dryer 5. The machine is arranged to transfer the vveb from the TAD section 4 to the yankee dryer 5. ln the yankee dryer 5 the Web 3 is further dried When being passed around a yankee drum 501. The yankee drum 501 is partly surrounded by a yankee hood 502. The Web is doctored off the yankee drum 501 by doctor blade 503 and is taken up by a reel (not shown).

According to the invention, the machine is arranged to apply to the Web 3 a heated fluid downstream of the transfer station 403 and upstream of the TAD cylinder 401. ln this embodiment, the heated ﬂuid comprises steam and/or moist air. For this, the machine comprises an ejector 404 located on a first side of the TAD fabric 402. The ejector 4()4 is arranged to apply the heated ﬂuid to the Web 3. The machine further comprises a Vacuum device 405 adapted to present a reduced pressure on a second side of the TAD fabric 402, opposite to the location of the ejector 404. Thus, the ejector 404 and the vacuum device are at the same position along the path of the Web, but on opposite sides of the Web. The Vacuum device 4()5 is adapted to mold the Web 3 into the TAD fabric 402. ln this embodiment, the vacuum device 405 is non-rotational.

Reference is made also to ﬁg. 2. Using the machine in fig. 1, an embodiment ofa method for producing a fibrous Web comprises the following sequence of steps: A Web 3 is formed Sl from a furnish. The Web 3 is transferred S2 to the TAD fabric 402. Heated ﬂuid is applied S3 to the Web 3 doWnstream of the transfer station 403 and upstream of the TAD cylinder 401. Air is draWn S4 through the Web 3, the TAD fabric 402, and the peripheral structure of the TAD cylinder 401. lt should be noted that the invention is applicable also to machines With more than one TAD cylinder. The TAD cylinders may form a sequence of cylinders along the path of the Web. Thereby. the machine is preferably arranged to apply to the Web the heated ﬂuid upstream of the first TAD cylinder in the sequence of TAD cylinders. HoWever, it is conceivable that the machine is arranged to apply to the Web a heated ﬂuid between tWo TAD cylinders. Thereby, the machine is still arranged to apply to the Web the heated fluid doWnstream of the transfer station and upstream of a TAD cylinder. More specifically, between the latter and the transfer station a further TAD cylinder inay be provided.

Reference is made to fig. 3, showing a machine Which is similar to the one in fig. 1, except for the following: The vacuum device 405 comprises a roll. Thereby, the tiine during Which the Web 3 is subjected by the application of steam from the ejector can be relatively long.

Reference is made to fig. 4, showing a machine Which is similar to the one in fig. 1, except for the following: The machine coinprises a molding device 406 located downstreain of the transfer station 403 and upstream of the TAD cylinder 401. The nioltliiig device is adapted to mold the Web 3 into the TAD fabric 402. The ejector 404 and the vacuuin device 405 are located downstreain of the moldiiig device 406.

Reference is made to fig. 5, showing a part of the machine in fig. 1. and a TAD air system for the machine. The TAD air system circulates the air from the interior of the TAD cylinder 401 via a circulation conduit 421. The circulation is provided by means of a circulation fan 414 in circulation conduit 421. The air is heated by a burner 411 fed by added air AA and fuel FL, such a natural gas. The heated air is fed to the TAD hood 407.

Some of the air from the TAD cylinder 401 is guided through an exhaust conduit 422. An exhaust fan 413 is provided in the eXhaust conduit 422. Some of this air is guided to the atmosphere as eXhaust EX. Some of the air in the exhaust conduit is fed by an ejector feeding conduit 423 to the ejector 404. A boost fan 412 is provided in the ejector feeding conduit 423.

Thereby, the machine is arranged so that the heated fluid applied to the Web 3 by the ejector 404 is provided by means of the air drawn through the Web 3, the TAD fabric 402, and the peripheral structure of the TAD cylinder 401. More specifically, some of the air drawn through the Web 3, the TAD fabric 402, and the peripheral structure of the TAD cylinder 401 is applied as the heated fluid to the Web 3.

Reference is made to fig. 6, showing an alternative manner of providing the heated fluid to the applied to the web. In the formiiig section 2, a vacuum bloWer 223 is arranged to provide a pressure gradient across the Web 3 in the dewatering region 212 to remove Water from the web. Water and moist air from the Suction boxes 214 are fed to a separator 221, in which 11 Water is removed. From the separator, moist air is fed by a feeding conduit 222 to the ejector 4()4. The vacuum blower 223 is provided in the feeding conduit 222. Thereby, the machine is arranged so that the heated fluid applied to the Web 3 is provided from an exhaust from the vacuum bloWer 223.

Reference is made to fig. 7, showing a further alternative manner of providing the heated ﬂuid to be applied to the Web. Air from the yankee hood 502 is guided through an exhaust conduit 5l l. An exhaust fan 512 is provided in the exhaust conduit 5 l l. Some of this air is guided to the atmosphere as exhaust EX. Some of the air in the exhaust conduit is fed by an ejector feeding eonduit 513 to the ejector 404. A boost fan 514 is provided in the ejeetor feeding conduit 513. Thereby, the machine is arranged so that the heated fluid applied to the Web 3 is provided by means of the eXhaust of the yankee hood 502.

Claims

1. A machine (1) for producing a fibrous Web, such as for tissue, for example paper tissue, comprising - a forming section (2) adapted to form a Web (3) froin a furnish, - and a through air drying (TAD) section (4), comprising a TAD cylinder (401) With a peripheral structure having a plurality of openings, the TAD section further comprising a TAD fabric (402) forming by means of a plurality of rollers an endless loop Which partially extends around the TAD cylinder (401), - the machine being arranged to transfer the Web (3) from the forming section (2) to the TAD fabric (402), Whereby the Web (3) is brought in contact With the TAD fabric (402) at a transfer station (403) located upstream of the TAD cylinder (401), - the machine being arranged to establish a pressure difference externally and internally of the TAD cylinder (401), so that air is draWn through the Web (3), the TAD fabric (402), and the peripheral structure of the TAD cylinder (401), - characterized in that the machine is arranged to apply to the Web (3) a heated fluid doWnstreani of the transfer station (403) and upstreain of the TAD cylinder (40 1).

2. A machine according to claim 1, Wherein the heated fluid comprises steam and/or moist air.

3. . A machine according to any one of the preceding claims, Wherein the machine comprises an ejector (404) located on a first side of the TAD fabric (402), by ineans of Which ejector (404) the application to the Web (3) of the heated fluid is provided.

4. . A machine according to claim 3, Wherein the machine comprises a vacuum device (405) adapted to present a reduced pressure on a second side of the TAD fabric (402), opposite to the location of the ej eotor (404).

5. . A machine according to claiin 4, Wherein the vacuum device (405) is adapted to mold the Web (3) into the TAD fabric (402).A machine according to any one ofclaims 4-5, Wherein the vacuum device (405) is non-rotational.

6. A machine according to any one of claims 4-5, Wherein the vacuum device (4()5) comprises a roll.

7. A machine according to any one of claims 3-7, Wherein the machine comprises a molding device (406) located doWnstream of the transfer station (403) and upstream of the TAD cylinder (401), and adapted to mold the Web (3) into the TAD fabric (402),

8. Wherein the ejector (404) is located doWnstream of the molding device.

9. A machine according to any one of the preceding claims, Wherein the machine is arranged so that the heated fluid applied to the Web (3) is provided by means of the air dravvn through the Web (3), the TAD fabric (402), and the peripheral structure of the TAD cylinder (401).

10. A machine according to any one of the preceding claims, Wherein the machine is arranged so that the heated fluid applied to the Web (3) is provided by means of steam from a biomass combustion process.

11. A machine according to any one of the preceding claims, Wherein the machine comprises a yankee dryer doWnstream of the TAD section (4), Wherein the machine is arranged so that the heated ﬂuid applied to the Web (3) is provided by means of an eXhaust of a hood of the yankee dryer.

12. A machine according to any one of the preceding claims, comprising a vacuum bloWer arranged to provide a pressure gradient across the Web in the forrning section to remove Water from the Web, Wherein the machine is arranged so that the heated ﬂuid applied to the Web (3) is provided from an exhaust from the vacuuin bloWer.

13. . A through air diying (TAD) section (4) for a machine for producing a fibrous Web, such as for tissue, for example paper tissue, comprisinga TAD cylinder (401) With a peripheral structure having a plurality of openings, and a TAD fabric (402) forming by means of a plurality of rollers an endless loop Which partially extends around the TAD cylinder (401), the TAD section (4) being arranged to receive a Web (3) from a forrning section (2) of the paper machine, Whereby the Web (3) is brought in contact With the TAD fabric (402) at a transfer station (403) located upstream of the TAD cylinder (401), the TAD section (4) being arranged to establish a pressure difference externally and internally of the TAD cylinder (401), so that air is draWn through the Web (3), the TAD fabric (402), and the peripheral structure of the TAD cylinder (401), characterized in that the TAD section (4) is arranged to apply to the Web (3) heated ﬂuid doWnstream of the transfer station (403) and upstream of the TAI) cylinder (401).

14. A method for producing a fibrous Web, such as for tissue, for example paper tissue, comprising forniing a Web (3) from a furnish, transferring the formed Web (3) to a through air drying (TAD) fabric (402), Which forms by means of a plurality of rollers an endless loop Which partially extends around a TAD cylinder (401) With a peripheral structure having a plurality of openings, Whereby the Web (3) is brought in contact With the TAD fabric (402) at a transfer station (403) located upstream of the TAD cylinder (401), establishing a pressure difference eXternally and internally of the TAD cylinder (401), so that air is draWn through the Web (3), the TAD fabric (402), and the peripheral structure of the TAD cylinder (401), characterized by applying to the Web (3) heated fluid downstream of the transfer station (403) and upstream of the TAD cylinder (401).