SE535179C2 - Ways of drying a pulp web and apparatus for drying such web - Google Patents

Abstract

'EG 'šâ 2G Truw! ABSTRNIIT* Ah errehgerhent (EG) fbr áryšrhg beišuâbse buåp borhbrisee e ëryihg bex(22), a web bbeiïšorr cerrrrbi unit (24), which ie bberetšve for berrïreiššbg theEeterefl peešršeh b? e web (44) bf befiiuâbee puäb dršed än *the dryârrg bbx (22), enee web fbhwerdihg device (28), which ie eberetive fbr fbrwerbåšhg the web (44)br' pušb threugh the erg/äng bex (22) end thrbugb the web besitâeh bbhïreš ubåt(24). The web beeiribh cehtrbâ unit (24) combršeee e guide reåier (54)errengement ebmbršsâng et Eeeet ene gušde rešâer (69, 62) ene äs oberetšve fbrdeiâverrng e pušp web (44), the šetereš bbeštšon bf which hee been cehtrefišed, eten ehgše bf -45“ re +45* te *the heršzbrrtei båahe. Eieeted for bubiäeeršbrr: Fšg. 2e

Description

AWAPATENT AB Andritz Technology and Asset Management GmbHKontor/Handiäggare Ansökningsnr Vår referensVäxjö/Erik Simonsson/ESN 8521046618 Ät ådETi-iÛBNÜF DRYENG A CELLULOSE PUL? VVÉEÉB ÅND :ÄNARRANGEMENT FÖR DRYENG SUCH A WEB štstisot.tbs__iri_irsri_tieriThe present invention reiates to an arrangement for drying ceiiuiosepuip, the arrangernent comprising a drying box, a Web position controi unit, 5 Which is operative for controiling the iaterai position of a Web of ceiiuiose puipdried in the drying box, and a Web forwarding device, which is operativa forforwarding the Web of pulp through the cirying box and through the Webposition controi unit.

The present invention further reiates to a method of drying a ceiiuiose1G puip in an arrangernent of the above referenced type.

Baokoround of the invention Celiuiose puip is often dried in a convective type of dryer operating in accordance With the air borne Web principie. An exarnpie of such a dryer is15 described in WO 2009/154549. Hot air is biown onto a Web of ceiiulose puip by means of upper biow boxas and tower biow boxes. The air biown by the biovv boxas transfer heat to the web to dry it, and aiso keeps the web fioating above the iower biow boxas. Hot air is suppiied to the bioW boxas by means of a cirouiation air system cornprising fans and steam radiators heating the20 drying air. A cornpiete ceiiuiose puip dryer is iiiustrated in WO Qwßdêtš, A miii producing ceiiuiose puip requires a very iarge space, such spacerequirement not oniy increasing the investment cost of the rniii, but aisomakes the rniii iess effective since both personnei, equipment and theceiiuiose puip as such needs to be transported over iong distances internatiy 25 in the rniii. 1G 2G Summary of the invention An object of the present invention is to provide an arrangement fordrying of a ceiiulose puip web, the arrangement being more space efficientthan the prior art arrangements.

This object is achieved by means of an arrangernent for dryingceiiuiose puip, the arrangement cornprising a drying box, a web positioncontrol unit, which is operativa for controiiing the iaterai position of a web ofceiiuiose pulp dried in the drying box, and a web forwarding device, which isoperativa for forwarding the web of pulp through the drying box and throughthe web position controi unit, wherein the web position controi unit is arrangedupstream, as seen with respect to the direction of forwarding the web, of theweb forwarding device, and cornprises a guide roiier arrangernent comprisingat: ieast one guide roiier and being operativa for deiivering a web of puip, theiaterai position of which has been controiied, at an angie of -45° to +45° to thehorizontai piane.

An advantage of this arrangement is that the arrangement can bemade quite iow, such that other devices, inciuding broke transfer devices forremoving places of puip from the drying box, can be convenientiy integratedwith the arrangement. According to one embodirnent, the guide roiierarrangernent is operativa for delivering a web of puip, the iaterai position ofwhich has been controiied, at an angie of -3G° to +30” to the horizontai piane.An advantage of this enfibodiment is that a further reduction of the height ofthe arrangement is enabied. According to a further embodirnant, the guidaroiier arrangement is operativa for deiiveririg a web of puip, the iateraiposition of which has been controiled, at an angie of -i5° to +15° to thehorizontai plana.

According to one embodiment the guide roiler arrangement comprisesa first guide roiier and a second guide rolier, with the second guide roiierbeing iocated downstream of the first guide rolier as seen in the direction offorwarding the web. Ari advantage of this embodiment is that efficient controiof the iateral position of the web can be achieved aiso in situations where theweb both enters and leaves the guide roiier arrangement at a iow angie, suchas -30° to +30°, to the horizontai piane. 2G 3 According to one embodiment the guide roiier arrangement isarranged inside a housing of the drying box. An advantage of thisembodiment is that the totai iength of the arrangement can be reduced, sincesome of the space required for the web position control unit, in particular inthe iongitudinai direction, as seen aiong the arrangernent, is integrated in thedrying box.

According to a further ernbodirnent the drying box comprises at ieastone deck cornprising biow boxas being operativa for biovving a gas towardsthe web, the guide roiier arrangernent being arranged in said deck. Anadvantage of this embodiment is that a particuiariy short totai iength of thearrangement can be achieved.

According to one embodiment biovv boxes are arranged in said at ieastone deck both upstrearn and downstream of said guide roiier arrangement.An advantage of this embodiment is that the guide roiier arrangement can beintegrated anywhere aiong the dec-k, such as a deck of a drying zone or of acooiing zone, vvhiie stiii rnaintaining most of the drying or cooiing capacity, asthe case may be, of that deck.

According to one embodiment said deck is included in a cooiing zoneof the drying box, said cooiing zone being operativa for cooiing the dried web.An advantage of this embodirnent is that the temperature is normaiiy ratheriow in the cooiing zone, which means that sensitive devices, such aseiectrcnics and control devices, associated with the guide roiier arrangementare not exposed to excessive temperatures.

According to one embodiment the drving box comprises at ieast onecoiumn of turning roiis around which the web of puip may be turned whenbeing forwarded between decks inciuded in the drving box, the guide roiierarrangement being arranged beiow said coiurnn of turning roiis. Anadvantage of this embodiment is that the guide roiier arrangement can beinstaiied in a part of the drying box where it causes minimum reduction of thecapacity of a cooiing zone or of a drying zone, as the case may be.

According to one entbodirnent at ieast a portion of a free distanceneeded for the web downstream of the guide roiier arrangement is arrangedinside a housing of the drying box. An advantage of this embodiment is that 'iÛ 4 the totai length of the arrangement can be reduced, without having tocompromise with the free tength that is desired for a proper function of theweb position controt unit.

According to one ernbodiment the guide rotter arrangement isarranged downstream of the drying box, as seen in the direction of forvvardingthe web. An advantage of this embodiment is that the drying box need not bemodified, causing minimum inftuehce on the drying and cooiing efficiency ofthe drying box.

According to one embodiment the web is forvvarded directiy from theguide roiter arrangement to the web forwarding device, the path of the webbeing changed less than +!-'tO° in a verticai direction between the guide roiierarrangement and the web forvvarding device. An advantage of thisembodiment is that the totai tength of the arrangement is minimized when theweb is forwarded directly from the web position controt unit to the webforwarding device.

According to one embodiment the drying box, the vveb position controiunit, and the web forwarding device are att mounted directiy on a commonmachine room fioor. An advantage of this embodiment is that thearrangernent can be made iow, as seen in a vertioai direction, which savesstructurat steei, and makes maintenance and supervision easier.

Another object of the present invention is to provide a method fordwing a celtuiose puip web, the method being more space efficient than theprior art method, This object is achieved by means of a method of drying a ceiiuiosepuip in an arrangement comprtsing a drying box, a web position controi unit,which is operativa for controiting the laterai position of a web of cetiuiose puipdried in the drying box, and a web forvvarding device, which is operativa forforwarding the web of puip through the drying box and through the webposition controi unit, the method comprising forvvarding the dried web to a guide roiier arrangement being inctudedin the web position controt unit and comprising at ieast one guide rotier, controliing the iaterat position of the web by means of the guide roiterarrangement , and 2G 5 deiivering the web from the guide roiier arrangement at an angle of-45° to +45° to the horizontal piane.

An advantage of this method is that the web is fonfvarded in a quite iowmanner downstream of the drying box, such that other process steps,including applying traction force to the web, measuring the properties of thedried web, removing pieces of puip from the drying box at unintentionai stops,etc, can be made to occur at a iow verticai ievei, just above a machine roomfioor, making inspection and maintenance easier. According to oneembodirnent a pulp web, the iaterai position of which has been controiied, isdeiivered from the guide roiier arrangement at an angie of -30° to +30° to thehorizontai piane. An advantage of this embodirnent is that other process stepscan be performed at an even iovver verticai ievei. According to a furtherembodiment, a puip web, the iaterai position of which has been controiied, isdeiivered from the guide roiier arrangement at an angie of -i5° to +15” to thehorizontal piane.

According to one embodiment the method further comprises forwardingthe web, after having passed the guide roiier arrangement, aiong a freedistance, aiong which the path of the Web being changed less than -i-/-1G° in averticai direction, at ieast a portion of said free distance being iocated inside ahousing of the drying box. An advantage of this embodiment is that theprocess steps ooourring in the arrangement can be made to occur aiong a short totai iength, reducing investment and maintenance costs.

According to one embodiment the method further comprises forwardingthe web directiy from the guide roiier arrangement to the web forwardingdevice, the path of the web being changed iess than +l-fb° in a vertioaidirection when being forvvarded from the guide roiier arrangernent to the webforwarding device. An advantage of this embodiment is that the totai iength ofthe arrangement is further reduced.

Further objects and features of the present invention vviii be apparentfrom the description and the ciaims. 'iO Brief description of the DrawinesThe inventien wiii now be described in more detail with reference te theappended drawings in which: Fig. 1 is a sohentatic side view, and iiiustrates an arrangernent fordrying ceiiuiose puip in aooordanoe with prior art.

Fig. 2a is a sohernatic side view, and iiiustrates an arrangernent fordrying ceiiuiose puip in aocordanoe with a first ernbedirnent of the presentinvennon.

Fig, 2b is an eniarged side view, and iiiustrates the area iib of Fig. 2a.

Fig. Zo is a top view, iiiustrating a web position controi unit iiiustrated inFig. 2a.

Fig. 2d is an eniarged side view, similar to that of Fig. 2b, andiiiustrates an optionai roiier.

Fig. Ba is a schernatic side view, and iiiustrates an arrangernent fordrying ceiiuiose puip in accordanoe with a second embodiment.

Fig. 3b is an eniarged side view, and iiiustrates the area iiib of Fig. 3a.

Fig. 4:a is a schenfiatio side view, and iiiustrates an arrangernent fordrying oeiiuiose puip in aeeordance with a third embodiment.

Fig. 4b is an eniarged side view, and iiiustrates the area iVb of Fig. 4a.

Fig. 5 is an eniarged side view and iiiustrates an arrangement fordrying ceiiuiose puip in aocordance with a fourth entbodintent.

Description of preferred entbodiments Fig. i iiiustrates a prior art arrangernent i for drying oeiiuiose puip. Thearrangemant 'i oomprises a drying box 2 in which a web 3 of oeiiuiose puip isdried. The drying box 2 could be simiiar to the drying box iiiustrated inWO 39136315, The dried ceiiuiose puip web 3 ieaves the drying box 2 and isforvvarded to a web position centre! roii 4. The web position oontroi roii 4centrets the iaterai position of the web. After the roii 4, the web 3 is forwardedverticaiiy upwards to a roii 5. The verticai distance i-i from the web positioneontroi roii 4 to the roii 5 shouid be at ieast 9,5 times the width of the web 3,to avoid wrinkiing of the web. The web 3 is then forvtfarded through ameasurement station 6 anaiysing the properties, sueh as rnoisture content,basis weight, any presence of spets of dirt and brightness, of the web 3. A 7 web puiling nlp 7 is arranged after the measurement station 6 to puli the web3 through the drying box 2, and the rolis 4, 5. The web 3 is then transferred toa cutter 8 for being cut to suitable lengths for being baled for transport.Alternativeiy, the dried pulp may be coiiected on a so-called pope reeler onwhich a reel of dried pulp is formed. A broke transfer device 9 is operativa fortransferring pieces of web getting stuck inside the drying box 2 atunintentionai stops from the drying box 2 to a puip pit 1G, in which the piecesof puip may be dissolved and utilized for producing a new puip web.

Fig. 2a iliustrates en arrangement 2G for drying ceilulose pulp inaccordance with a first ernbodiment of the present invention. Fig. 2biliustrates an enlargement of the area llb of Fig. 2a. The arrangement 20comprises a drying box 22, a web position control unit 24, a measurementstation 26, a web forwarding device 28, a cutter 30, and a broke transferdevice 32.

The drying box 22 cornprises a housing 34. inside the housing 34 adrying zone 36 and a cooling zone 38 are arranged. The drying zone 36comprises a number of drying decks 4G, each such desk 4D comprising anumber of upper blow boxes 42 and tower biow boxas 43 that are arrangedfor blowing a hot drying gas towards a celiulose puip web 44. Typicaliy, adrying box 22 may comprise 10 to 50 drying decks 4G arranged one abovethe other, although Fig. 2a in the interest of rnaintaining clarity of illustrationonly illustrates the lower portion of the drying box 22. The lower blow boxes43 are operative for keeping the web 44 in a “floating" condition, such that theweb 44 becomes airborne during the drying process. Typicaily air of atemperature of 80 to 25Û°C is utilized for the drying process. The ceilulosepuip entering the dryihg box 22, from an upstream web forming station, notshown in Fig. 2a, typicaliy has a dry soiids content of 40-60 % by weight, andthe celiulose puip web leaving the drying box 22 has a dry soiids content oftypicaily 85-95 % by weight. The celiuiose puip web 44 leaving the drying box22 typicaliy has a basis weight of SÛQ to 1569 glrnz, when measured at amoisture content of 0.11 kg water per kg dry substance, and a thickness ofOßmßmm 6 The cooiing zone 36 comprises at ieast one cooiing deck 46, in Fig. 2atwo such cooiing decks 46 are iiiustrated, each such deck 46 comprising anumber of upper biow boxes 47 and icwer biow boxas 46 that are arrangedfor biowing a cooiing gas towards the ceiiuiose puip web 44. The tower biowboxas 46 are operativa for keeping the web 44 in a “fioating" condition, suchthat the web 44 becomes airborne during the cooiing process. Typicaiiy, air ofa temperature of 15 to 40°C is utiiized as a cooiing gas for the cooiingprocess. An isoiated waii 49 separates the drying zone 36 from the cooiingzone 38.

At a first end 50 of the housing 34 a first coiumn of turnings roiis 51 isarranged, and at a second end 52 of the housing 34 a second ooiumn ofturning roiis 53 is arranged. The web 44 is turned around the turning roiis 51,53 when being transferred from one deck 40, 46 to another deck 40, 46 andwhen being transferred from the drying zone 36 to the cooiing zone 68.

The web position control unit 24 cornprises a guide roiier arrangement54, tvvo Cameras 56, of which oniy one is visibie in Fig. 2a, and two iightsources 56, of which oniy one is visibie in Fig. 2a. The guide roiierarrangement 54, the cameras 56, and the two iight sources 58 are arrangedinside the housing 34, and in fact inside the cooiing zone 36. in accordancewith an aiternative ernbodiment, the web position control unit 24 couid bearranged with oniy one camera 66 and oniy one Eight source 56, since it issometimes enough to keep track on just one of the iaterai sides of the web44.

Fig. 2b iiiustrates the web position controi unit 24 in more detaii. Theguide roiier arrangernent 54 comprises a first guide roiier 60 and a secondguide roiier 62. The direction of forwarding the web 44 is indicated by anarrow T. The web 44 is forwarded above the first roiier 60 and beiow thesecond roiier 62. The upper end of the first roiier 60 is iocated at a higherievei than the icwer end of the second roiier 62, meaning that the web 44 wiiimake two turns, firstiy downwards when passing the first roiier 60, andsecondiy upwards when passing the second roiier 62, as iiiustrated in Fig. 2b.The first and second roiiers 60, 62 are mounted on a roiier rack 64. The roiierrack 64 is mounted on a foundation 66 in such a manner that the roiier rack 16 9 64 may siide on the foundation 66 aiong an arc, having a centrai axis A. Theweb 44 ieaves the guide roiier arrangement 64 at an angie B to the horizontaipiano of about +5° as iiiustrated in Fig. 2b, i.e., at an angle of 5° above thehorizontai piano. Typicaiiy, the angie B would be from -45° to + 452 i.e., theweb 44 wouid leave the guide roiier arrangement 54 at an angie B in therange of from 45° beiow the horizontai plana, to 45° above the horizontaipiane. More often the angie B wouid be in the range of -30° to +36°, or evenin the range of-i5° to +15? Cameras 56 and iight sources 56 are typicaliy located a short distance,typicaiiy 0.2 to 'i m, downstream of second roiier 62.

Fig. 2c iiiustrates the web position controi unit 24 as seen from above.Arrows S indicate how the roiier rack 64 may siide on the foundation 66iilustrated in Fig. Zb, such siiding movement occurring aiong a horizontai archaving its centre in the axis A. The siiding of the roiier rack 64 on thefoundation, and along the arc having its centre in axis A, infiuences theposition of the web 44. The direction of forwarding the web 44 is indicated byan arrow "i" in Fig 2c. The roiiers 60, 62 are provided with motors 6Y, 68 thatare utiiized during start up of the drying process, by forvvarding a narrow "fait"of puip there through. When the puip drying process is in normai operationmotors 67, 68 are inactive. if the roiier rack 64 is siid to the ieft as seen in the direction T offorwarding the web 44, i.e., upwards in the iiiustration of Fig. 2c, the web 44 isforced to the ieft. if the roiler rack 64 is siid to the right as seen in the directionT of forwarding the web 44, i.e., downwards in the illustration of Fig. 2c, theweb 44 is forced to the right. The two cameras 66, one camera 56 beingarranged on each iaterai side of the web 44, as iiiustrated in Fig. Zc, andabove the web 44, as iiiustrated in Fig. 2b, registers an amount of Eightpassing by the web 44 from the respective tight source 56 arranged verticaiiybeiow the respective camera 56, and below the web 44, as iliustrated in Fig.2b and 2c. The two cameras 66 are connected to a controi system 76,iiiustrated in Fig. Zc. The control system 76 anaiyses signais from cameras66, and determines, based on such signais, whether or not it is necessary toadiust the iaterai position of the web 44. if such adiustment is necessary, 2G controi system 7G sends a signai to servomotor 72 to make roiier rack 64siide to the fett or to the right, as the case may be, to adjust the iateraiposition ot the web 44. A controi system ot this type is avaiiabie from FiteCorporation, Dkiahoma city, USA.

Fig. 2a iiiustrates a free distance FD being the distance from thesecond roiier 62 of the roiier arrangernent 54 to a support roiier 74. The freedistance FD is preterabiy at ieast 0.5 times the width W, iiiustrated in Fig. 2G,ot the web 44. As can be seen from a reference to Fig. 2a, most of the freedistance FD is iocated inside the actual housing 34 of the drying box 22, anda substantiai portion of the free distance FD is iocated inside the actuaicooiing zone 38. As iiiustrated in Fig. Zb, upper and tower biow boxas 47, 48may even be arranged downstream of guide roiier arrangement 54. The factthat a substantiai portion ot the free distance FD is iocated inside the housing34 makes it possibie to design an arrangement 2G for drying a very wideceiiuiose puip web, such as a puip web 44 having a width W of 8-20 meters,without substantiaiiy increasing the totai iength of the arrangement 2G,compared to a prior art arrangement drying a puip web of a tower width. Ofcourse the present arrangement 20 can be utiiized aiso for drying a putp web44 of tower width, such as a width VV ot 2 to 8 meters, in which case a verycompact and short arrangement is obtained. in addition to the tree distanceFD between the second guide roiier 62 ct the guide roiier arrangement 54 to asupport roiier 74, it is aiso preferabie that there is another tree distanceiocated upstream ot the first guide roiier du ot the guide roiier arrangement54. Hence, there is preterabiy another tree distance located between theiowest turning roii 51 and the first guide roiier 60, said another free distancebeing preterabiy at ieast equai to the width W ct the web 44.

Fig. 2a further iiiustrates how the puip web 44, after having passedthrough the web position controi unit 24 and the support roiier 74 arrangeddownstream thereof, as seen with reference to the direction of forwarding thepuip web 44, is fonivarded to the measurement station 26. The measurementstation 26 inciudes a measurement beam 76 being supported by ameasurement rack 78 and comprising one or severai measurement devices,such as moisture measurement devices, brightness measurement devices, 19 11 basis weight measurement devices etc. The measurement beam 78measures those various properties of the web 44 being passed through thestation 28. The measurement rack 78 is, same as with the housing 84 of thedrying box 22 and the web position controi unit 24, mounted directiy on amachine room fioor 80. By “mounted directiy on a machine room fioor” ismeant that no intermediate stands, vibratiori dampers, etc of a height of morethan about i rn are arranged between the machine room fioor 89 and therespective rack 78, :trying box 22, etc.

The web 44 is fonfvarded further to the web forwarding device 28. Theweb forwarding device 28 cornprises a nip roiier 82 and a drive roiier 84arranged verticaiiy above each other and forming between them a nip 88through which the web 44 is forwarded. The drive roiier 84 is driven by amotor (not shown) and appiy a traction force to the web 44, forcing the webthrough the drying box 22, the web position control unit 24 and themeasurement station 26. The roiiers 82, 84 are arranged in a drive roiier rack88, which is mounted directiy on the machine room fioor 89.

The web 44 is further forwarded, above a puip pit 90, from the webforwarding device 28 to the cutter 89 for being cut to sheets suitabie for beingbaied. As aiternative to being cut and then baied, the dried puip may becoiiected on a so-caiied pope reeier on which a reei of dried puip is formed.

The broke transfer device 32 is operated when an operation probiemhas occurred and pieces of puip has gotteri stuck inside the housing 34. Thebroke transfer device 32 comprises a puip forvvarding siide 92 which extendsfrom the drive roiier rack 88 to a iift 94 which can be moved verticaiiy aiongthe housing 34, as indicated by an arrow V. The puip forvvarding siide 92 ismounted en a siide stretching roiier 98. The siide stretching roiier 98 makes itpossibie to adept the length of the puip forwarding siide 92 to the presentposition of the iift 94, such that the siide 92 is aiways in a stretched conditionwhen in use. When puip pieces has gotten stuck inside the housing 34 anoperator directs the iift 94 to be in iine with that deck 48 at which puip pieceshave been stuck. The operator takes out puip pieces from the deck 48 inquestion, puts the puip pieces on puip forwarding siide 92, and aiiows thepuip pieces to giide aiong siide 92, such that the puip pieces fait into the puip 12 pit 90, as indicated by an arrow P. it couid be noted that during such puipcieaning procedure, there is no web 44 extending from the web forwardingdevice 28 to the cutter 30, giving a free passage for the puip pieces to passfrom the siide 92 and down into the puip pit 90, in which the pieces of puip aredissoived and utiiized for producing a new puip web.

The fact that the puip web 44 ieaves the second roiier 62 of the guideroiier arrangernent 54 at an angie B of -45° to +45° to the horizontai piane, asiiiustrated with reference to Fig. 2b, makes it possibie to arrange themeasurement rack 76 and the drive roiier rack 68 directiy on the machineroom fioor 80. Thanks to this fact, the puip forwarding siide 92 wiii siope fromthe iift 94 towards the puip pit 90 aiso when the iift 94 is moved to the towerdecks 40 of the drying box 22. This is, as iiiustrated in Fig. t, not possibie inthe prior art, where measurement station 6 and web puiiing station 7 areiocated high above the ground, mounted on a separate stand, making itdifficuit in the prior att to transport puip pieces removed from iower decks tothe puip pit 10. Returning to Fig. 2a, a vertical distance i) between themachine room fioor 80 and the web 44 is preferabiy iess than 2 rn, aii the wayfrom the guide roiier arrangement 54 to the web fon/varding device 26.

Fig. 2d is a schernatic and eniarged side view, simiiar to that of Fig. 2b,and iiiustrates an optionai third guide roiier 63 added to the web positioncontroi unit 24. A guide roiier arrangement 54 is arranged in a sirniiar manneras described hereinbefore with reference to Figs. 2a-2c, and comprises a firstguide roiier 60, a second guide roiier 62, and the third guide roiier 63, which isarranged downstream of the second guide roiier 62, as seen in the directionof forwarding the web 44, indicated by arrow T. The first, second and thirdguide roiiers 60, 62, 63 are arranged, in this order as seen in the direction offorwarding the web 44, on a common roiier rack 65. The roiier rack 65 ismounted on a foundation 69 in such a manner that the roiier rack 65 maysiide horizontaiiy on the foundation 69 along a horizontai arc, in a simiiarmanner as described hereinbefore with reference to Figs. 2b and 2cconcerning the roiier rack 64 siiding on the foundation 66, in order to controithe iaterai position of the web 44. Upon controiiing the iaterai position of theweb 44 aii three roiiers 60, 62 and 63 move together, since they are mounted 16 36 13 on the common roiier rack 65. As can be seen from Fig. Zd, the web 44ieaves second guide roiier 62 at an angie of about 36° to the horizontai piane.Optionai third guide roiier 63, iocated downstrearn of roiier 62, breaks thepath of web 44, such that web 44 traveis aiong a substantiaiiy horizontai pathdownstream of roiler 63. The vertical ievei of web 44 is substantiaiiy the samedownstream of third guide roiier 63 as upstream of first guide roiier 66.Ûpticnai third guide roiier 63 may be utiiized in such cases where there is adesire to have the web 44 ieaving guide roiier arrangement 54 aiong asubstantiaiiy horizontai path, ie., at: an angie to the horizontai piane of aboutO? Fig. 3a iiiustrates an arrangement 126 for drying ceiiuiose puip inaccordance with a second embodiment of the present invention. Fig. Bbiiiustrates an eniargemerit of the area iiib of Fig. Ba. Those parts of thearrangement 126 that are sirniiar to the parts of arrangement 20 describedhereinbefore with reference to Figs. 2a-2c have been given the samereference numbers and are not described in detaii. The arrangement 126oomprises a drying box 122, a web position controi unit 124, a measurementstation 26, a web forwarding device 28, a cutter 36, and a broke transferdevice 32.

The drying box 122 oomprises a housing 134. inside the housing 134 adrying zone 36 and a cooiing zone 136 are arranged. The drying zone 36comprises a number of drying decks 40 that are sirniiar to those describedhereinbefore with reference to Fig. 2a.

The cooiing zone 136 comprises at ieast one cooiing deck 46, in Fig.Sa two such cooiing decks 46 are iiiustrated, each such desk 46 comprising anumber of upper biow boxas 47 and tower biow boxas 48 that are arrangedfor biowing a cooiing gas towards the oeiiuiose puip web 44.

At a first end 66 of the housing 134 a first coiumn of turnings roiis 51 isarranged, and at a second end 52 of the housing 134 a second coiumn ofturning roiis 53 is arranged. The web 44 is turned around the turning roiis 51,53 when being transferred from one deck 46, 46 to another deck 46, 46 andwhen being transferred from the drying zone 36 to the cooiing zone 138. 3G 14 The web position control unit 124 comprises a guide roller arrangernent54, two Cameras 55, of which only one is visible in Fig. 3a, and a two lightsources 58, of which only one is visible in Fig. Sa. The guide rollerarrangement 54 is arranged inside the housing 134, just below the secondcolumn of turning rolls 53. The carneras 55 and the light sources 55 arearranged just outside of the housing 134. ln accordance with an alternativeernbodirnent, the web position control unit 124 could be arranged with onlyone camera 55 and only one light source 55, since it is sometimes enough tokeep track on just one of the lateral sides of the web 44.

Fig. Sh illustrates the web position control unit 124 in more detail. Theguide roller arrangernent 54 comprises a first guide roller 65 and a secondguide roller 52 and functions in a similar manner as the guide rollerarrangement 54 described hereinbefore with reference to Figs. 2a-2c.

The first roller 50 and the second roller 52 of guide roller arrangement54 of web position control unit 'l24 are located at substantially the samehorizontal level, meaning that the web 44 will make two turns, firstlydownwards when passing the first roller 50, and seoondiy upwards whenpassing the second roller 52, as illustrated in Fig. 3b. The web 44 leaves theguide roller arrangement 54, in the direction of the arrow T, at an angle B tothe horizontal plans of about -i-'i0° as illustrated in Fig. Bb, i.e., at an angle ofi0° above the horizontal plane. Typicallv, the angle B would be from ~45° to+45°, ie., the web 44 would leave the guide roller arrangement 54 at an angleB in the range of from 45° below to the horizontal piane, to 45° above thehorizontal plans. lVlore often the angle B would be in the range of -3G° to+30°, or even in the range of -'i5° to +l5°. in the embodiment illustrated in Fig. Bb the first and second guiderollers 50, 52 are mounted on a roller rack 54 which is mounted on an angledfoundation 155. The roller rack 54 is, due to the foundation 155, tilted at anangle which is similar to the angle B, i.e., at an angle of about +iO° to thehorizontal plane. The roller rack 54 may slide on the foundation 156 along atilted arc, having a central axis A, the central axis A being tilted about 'iO° tothe vertical plane. Utilizing a tilted foundation 155 may be advantageous tothe control of the lateral position of the web 44 when the angle 5 behrveen the 1D 3D web 44 leaving guide roiier arrangement 54 and the horizontal piane is fromabout 10° to about 45°, or from -10° to about -45°, Fig. Sa iilustrates a free distance FD being the distance from thesecond roiier 62 of guide rolier arrangement 54 to a nip 8b of the webforwarding device 28. The web forwarding device 28 comprises a hip roiier 82and a drive roiier 84 arranged to generate a traction force to the web 44,forcing the web through the drying box 122, the web position controi unit 124and the measurement station 26. The roiiers 82, 84 are arranged in a driveroiier rack 88, which is rnounted on the machine room fioor BOIThe freedistance FD is preferabiy at ieast 0.5 times the width of the web 44. As can beseen from a reference to Fig. 3a, a part of the free distance FD is iocatedinside the actuai housing 134, and the rest of the free distance FD is iocatedbetween the housing 134 and the web forwarding device 28.

As is iiiustrated in Fig. 3a a support roiier 174 is iocated between thesecond roiier 62 of the guide roiier arrangernent 54 and the nip Bb of the webforwarding device 28. The support roiier 174 stabilizes the web 44 todecrease fiuttering of the web 44 upon entry into the measurement station 26,such that reiiabie measurements are ensured.

Fig. 3b iiiustrates the support roiier 174 in more detaii. The supportroiier 174 is mounted on a support roiier rack 175 which is mounted directiyon a machine room fioor 8G, on which aiso the housing 134 and the guideroiier arrangement 54 are mounted. The support roiier 174 changes the pathof the web 44 to a very iimited degree. As iiiustrated in Fig. 3b, the supportroiier 174 changes the path, in the verticai direction, of the web 44 by anangie C of about + 3? Typicaliy, the angie C wouid be from -1Ü° to + 102 i.e.,the support roiier 174 would change the path of the web 44 in the range offrom 1G° beiow the path that the web 44 has after the second roiier 62, to 1Û°above the path that the web 44 has after the second roiler 62. More often theangie C wouid be in the range of -5° to +5°.Such a smaii change of path, i.e.,iess than 10°, and more often iess than 5°, wouid not induce any webwrinkiing, and would not interfere with the required free distance FD, althoughthe support roiier 174 is in fact located aiong the free distance FD, asiiiustrated in Fig. 3a. According to one embodimeht, the support roiier 174 1G 16 couid be provided with a very smooth surface, for exampie a chromium-piatedsurface, to obtain a minimum friction and, hence, a minimum interference withthe web 44. Continuing with Fig. Ba, the measurement station 26 wouidnormaiiy perform most of the measurements on the web 44 in a contact-free,or at ieast iow contact, manner. Hence, the measurement station 26 wouidnot induce any web wrinkiing, and wouid not interfere with the required freedistance FD, aithough the measurement station 26 is in fact located aiong thefree distance FD, as iiiustrated in Fig. Sa. i-ienoe, the support roiier 174 andthe measurement station 26 wiii not resuit in a negative effect on the freedistance FD required between the roiier 62 and the nip 86. As iong as thepath of the web 44 is changed by iess than -i-/-10° in a vertical directionbetween the guide roiier arrangement 54 and the web forwarding device 28,and the web 44 is not forwarded through any nip formed between roiiers orsirniiar device substantiaiiy restricting the iaterai movement of the web 44,such forwarding is defined as a ”direct” fonivarding of the web 44 from theguide roiier arrangement 54 to the web forvvarding device 28.

The fact that a portion of the tree distance FD is iocated inside thehousing 134, and another portion of the free distance FD is iocated betweenthe housing 134 and the web forwarding device 28, makes it possibie todesign an arrangernerit 12Q for drying a very wide oeiiuiose puip web, such asa puip web 44 having a width of 8-20 meters, without substantiaiiy increasingthe totai iength of the arrangement 120, compared to arrangements dryingpuip webs of a tower width. Furthermore, with the arrangement 120 the webposition controi unit 'E24 does not interfere with the cooiing zone 138 and theupper and tower biow bcxes 47, 48 arranged therein, meaning that thecooiing effect of the cooiing zone 138 wiii not be impaired by the fact that theweb position controi unit 124 is partiy mounted inside the housing 134 of thedrying box 122.

Fig. Sia further iiiustrates how the puip web 44, after having passedthrough the web position controi unit 124, the support roiier 174, themeasurement station 26, and the web forwarding device 28, is furtherforwarded, above a puip pit 90, from the web forwarding device 28 to thecutter 3G for being cut to sheets suitabie for being baied. 3G 17 The broke transfer device 32 is operated in substantiaiiy the samemanner as described hereinioefere with reference te Fig. 2a, and comprisesthe same components. The fact that the puip web 44 teaves the second roiier62 of the guide roiier arrangement 54 at an angte B of -45° to +45° te thehorizontai piane, as iiiustrated with reference to Fig, Sto, makes it possibie toarrange the measurement rack 78 and the drive roiier rack 88 directiy on themachine room fioor 80. Thanks to this fact, a puip forwarding siide 92 of thebroke transfer device 32 wiii siope from a iift 94 towards the puip pit 90 aisowhen the iifi: 94 is moved te the tower decks 40 of the drying box 122.

Fig. 4a iiiustrates an arrangement 220 for drying ceiiuiose puip inacoordance with a third embodiment of the present invention. Fig. 4biiiustrates an eniargement of the area iVb of Fig. 4a. Those parts of thearrangement 220 that are similar to the parts of arrangement 2G describedhereinbefore with reference to Figs. 2a-2c have been given the samereference numbers and are not described in detaii. The arrangement 220cornprises a drying box 222, a web position controi unit 224, a measurementstation 25, a web forwarding device 28, a cutter 39, and a broke transferdevice 32.

The drying box 222 cornprises a housing 234. inside the housing 234 adrying zone 36 and a cooiing zone 238 are arranged. The drying zone 36comprises a number of drying decks that are simiiar to the drying decks 4Gdescribed hereinbefere with reference te Fig. 2a.

The cooiing zone 238 comprises at ieast one cooiing desk 46, in Fig.4a two such cooiing decks 43 are iiiustrated, each such deck 46 comprising anumber of upper blow boxes 47' and tower biow bexes 48 that are arrangedfor biowing a oeoting gas towards the oeiiuiose puip web 44.

The housing 234 comprises turning roiis 51, 53 arranged in a similarmanner as described hereinbefore with reference to Fig. 2a.

The web position controi unit 224 is arranged just after the housing234, as seen in the direction T of forwarding the web 44, and comprises aguide roiier arrangement 54, two carrieras 56, ef which oniy one is visibie inFig. 4a, and a two tight sources 58, of which oniy one is visibie in Fig. 4a. 18 Fig. 4b iiiustrates the web position controt unit 224 in more detaii. Theguide roiier arrangement 54 combrises a first guide roiier 60 and a secondguide roiier 62 and functions in a sirniiar mannar as the guide roiierarrangement 54 described hereinbefore with reference to Figs. 2a-2c, The web 44 ieaves the guide roiier arrangement 54, in the direction ofthe arrow T, at an angie B to the horizontai piane of about +t6° as iiiustratedin Fig. 4bi Typicaiiy, the angie B wouid be from -46° to +45°, ie., the web 44wouid ieave the guide roiier arrangement 54 at an angie B in the range offrom 45° beiow to the horizontai piahe, to 45° above the horizontai piane.More often the angie B wouid be in the range of -30° to +80°, or even in therange of -t6° to +15? Fig. 4a iiiustrates a free distance FD being the distance from thesecond roiier 62 of the guide roiier arrangement 54 to a nip 86 of the webforwarding device 28. The web forvvarding device 28 comprises a nio roiier 82and a drive roiier 84 arranged to generate a drag to the web 44, forcing theweb through the drying box 222? the web position controi unit 224 and themeasurement station 26, The roiiers 82, 84 are arranged in a drive roiter rack88, which is mounted directiy on the machine room floor 80. The free distanceFB is preterabiy at ieast 0.5 times the width of the web 44.

As seen from a reference to Figi 4a, the measurement station 26 isiocated between the guide roiier arrangement 54 and the nio 86, ie., aiongthe free distance FD. The measurement station 26 wouid normaiiy performmost of the measurements on the web 44 in a contact-free, or at ieast iowcontact, manner. Fience, the measurement station 26 wouid not induce anyweb wrinkiing, and wouid not interfere with the required free distance FD,aithough the measurement station 26 is in fact iocated aiong the free distanceFD, as iiiustrated in Fig. 4a.

The fact that the free distance FD is iocated between the housing 284and the web forwarding device 28, the measurement station 26 not giving anegative impact on the free distance FU required between the roiier 62 andthe nip 86, makes it oossibie to design an arrangement 226 for drying a verywide ceiiuiose buip web, such as a puip web 44 having a width W of 8-20meters, with just a moderate increase in the totai iength of the arrangement 19 220, compared to arrangements drying pulp webs of a tower width. With thearrangement 220 the web position controi unit 224 does not interfere with thecooiing zone 238, meaning that the cooling effect of the cooiing zone 238 wiiinot be impaired by the web position controi unit 224.

Fig. 4a further iiiustrates how the puip web 44, after having passedthrough the web position control unit 224, the measurement station 26, andthe web forwarding device 28, is further forvvarded, above a puip pit 90, fromthe web forwarding device 28 to the outter 3G for being cut to sheets suitabiefor being loaled.

The broke transfer device 32 is operated in substantiaily the samemanner as described hereinbefore with reference to Fig. 2a, and comprisesthe same components. The fact that the puip web 44 ieaves the second roiier62 of the guide roiier arrangement 54 at an arigie B of -45° to +45° to thehorizontai piane, as iliustrated with reference to Fig. 4b, makes it possibie toarrange the measurement rack 78 and the drive rolier rack 88 directiy on themachine room floor 80. Thanks to this fact, a puip forwarding siide 92 of thebroke transfer device 32 wiii slopa from a iift 94 towards the puip pit 9G aisowhen the iift 94 is moved to the tower decks of the drying box 222.

Fig. 5 iiiustrates an arrangement 320 for drying ceiiuiose puip inaccordance with a fourth embodiment of the present invention. Those parts ofthe arrangement 320 that are simiiar to the parts of arrangernent 20 describedhereinbefore with reference to Figs. 2a-2c have been given the samereference numbers and are not described in detaii. The arrangement 326 isiiiustrated in Fig. 5 in a sirniiar perspective as that of Figs. 2b and 3b. Thoseparts of the arrangement 320 that are not iliustrated in Fig. 5 are similar if notidenticai to the corresponding parts of the arrangement 20 as iiiustrated inFig. 2a.

Returning to Fig. 5, the arrangement 320 comprises a drying box 322,a web position controi unit 324, a measurement station 26, a web forvvardingdevice 28, a cutter (not shown), and a broke transfer device (aiso not shown).The drying box 322 comprises a housing 334. inside the housing 334 a dryingzone and a cooling zone are arranged in a similar manner as describedhereinbefore with reference to Fig. 2a.

The web position control unit 324 cornprises a guide roller arrangement354, at least one camera 56 and at least one light source 66. The guide rollerarrangement 364 is arranged inside the housing 334, just below a secondcolumn of turning rolls 53. The camera 66 and the light source 63 arearranged lust outside of the housing 334.

The guide roller arrangement 354 comprises a single guide roller 360and functions according to a similar principle as the guide roller arrangement54 described hereinbefore with reference to Fig. 2o, with the single guideroller 360 of guide roller arrangement 354 moving along an arc having itscentre in the axls A.

The web 44 is forwarded betvveen blow boxes 47, 48 and enters webposition control unit 324 substantially horizontally, makes a turn upwardswhen passing the single guide roller 360, and leaves the guide rollerarrangement 354, in the direction of the arrow T, at an angle B to thehorizontal plane of about 30° as illustrated in Fig. 5. Typicailv, the angle Bwould be from -45° to +45°, ie., the web 44 would leave the guide rollerarrangernent 364 at an angle B in the range of from 45° below to thehorizontal plane, to 46° above the horizontal plane. More often the angle Bwould be in the range of -30° to +30°, or even in the range of -t5° to +16°. ltwill be appreciated that the web 44 would need to make at least some turnaround single guide roller 360, and hence encircle single guide roller 360 tosome degree, to make it possible for the single guide roller 360 to control thelateral position of web 44. ilence, if the angle B is around 0°, for example inthe range of -l5° to +l5°, it may be suitable to have one or more roliersarranged upstream of single guide roller 360 such that web 44 in such a caseis forwfarded towards single guide roller 360 at an angle. For example, lf angleB is 0°, it would be suitable that the web 44 enters single guide roller 360 atan angle of for example 20-45° to the horizontal plane, such that the web 44in such a case encircles the single guide roller 360 to a similar degree asillustrated in Fig. 6. With a single guide roller 360 it would be suitable that anangle BG, illustrated in Fig. 5, between web 44 entering single guide roller360 and web 44 leaving single guide roller 360 is in the range of 100-160”.still being within the above specified range for the angle B. 1G 21 ln the embodiment iliustrated in Fig. 5 the single guide roller 366 isrnounted on a roller rack 364 which is mounted on an angled foundation 366,in a similar manner as described hereinbefore with reference to Fig. 3b.Returning to Fig. 5, the roller rack 364 is, due to the foundation 366, tilted atan angle which is similar to the angle B, i.e., at an angle of about 36° to thehorizontal plane. The roller rack 364 may slide on the foundation 366 along atilted arc, having a central axis A, the central axis A being tilted at an angleAE of about 60° to the horizontal plana. tltilizing the tilted foundation 366 maybe advantageous to the control of the lateral position of the web 44 since theangle B between the web 44 leaving guide roller arrangement 354 and thehorizontal plans is 30°, ie., in the range of about 'l6° to about 45” as notedhereinbefore with reference to Fig. 3b.

Fig. 5 illustrates how the web 44 is forvvarded directly from the guideroller arrangernent 354 to the web forwarding device 28, along a free distanceFD being the distance from the single guide roller 360 of guide rollerarrangement 354 to a nio 66 of the web forwarding device 28. The freedistance FD is preferably at least 6.5 times the width of the web 44. As can beseen from a reference to Fig. 5, a part of the free distance FD is locatedinside the actual housing 334, and the rest of the free distance FD is locatedbetween the housing 334 and the web forwarding device 26. The drying box322, the web position control unit 324, the measurement station 26 and theweb forwarding device 26 are all mounted directly on a common machineroom floor 80.

The fact that a portion of the free distance FD is located inside thehousing 334, and another portion of the free distance FD is located betweenthe housing 334 and the web forwarding device 28, makes the arrangement320 compact. The fact that the angle B is within the range of -45° to +45°makes the arrangernent 326 low, such that a broke transfer device 32 of thetype illustrated in Fig. 2a can be conveniently arranged. ln accordance with afurther alternative embodiment, the guide roller arrangement 354 comprisingthe single guide roller 360 could be arranged just outside of the housing 334,in a similar manner as the guide roller arrangement 54 of the arrangement 22 220 illustrated in Figs. 4a and 4b, making the arrangernent slightly longer, butstill quite low as seen in a vertical direction. lt will be appreclated that numerous variants of the above describedernbodiments are possible within the scope of the appended clairns. ' l-lereinbefore it has been described, with reference to for example Fig.2b, that the web 44 is fonvarded above the first roller 60 and below thesecond roller 62 of the guide roller arrangement 54. lt will be appreciated thatit would be egually possible to forward the web 44 below the first roller 66 andabove the second roller 62, efter a suitable vertical elevation of the roller rack64. l-lereinbefore it has been described, with reference to Figs. 2b and 2G,that the roller rack 64 may slide along foundation 66 along an arc having itscentre in the vertical axis A. it will be appreciated that roller rack 64 could, asalternative, be moved in another manner to control the lateral position of theweb 44. For example, the roller rack 64 could be turned around a vertical axiswhich is located in one lateral end of the roller rack 64, or a vertical axis whichis located at the centre of the roller rack 64 to achieve control of the lateralposition of the web. According to a further alternative, the roller rack 64 couldbe turned around a horizontal axis located at one lateral end of the roller rack64, or at the centre of the roller rack 64. lt would also be possible to controlthe position of one or more guide rollers 66, 62, 63, 366 independently fromthe roller rack 64. llenoe, control of the lateral position of the web 44 can beachieved in many different manners using at least one guide roller 66, 62,63, 360, the position of which can be controlled in the vertical and/orhorizontal direction. l-iereinbefore it has been described, with reference to Figs. Ze and Zb,that the guide roller arrangement 64 may be installed inside the cooling zone36 of the drying box 22. lt will be appreciated that it in case the drying boxdoes not comprise any cooling zone, the guide roller arrangement 54 couldbe installed, according to similar principles, in the drying zone of such adrying box, i-lereinbefore it has been described that the drying box 22 comprises ahousing 64 in which drying decks 40, and, optionally, Cooling decks 46, arearranged for drying a pulp web in aocordance with the air borne web principle, 23 in accordance with this principie the web is torvvarded in a horizontai directionbetween upper and tower blow boxes 42, 43, 47, 48 biowing air towards theweb. it wiil be appreoiated that an arrangernent for drying ceiiuiose puipcould, as alternative, inciude a dryihg box operating in accordance withanother principie. One exarnpie of such another principle is the so-caiiedverticai web dryer in which the web is torirvarded, in a verticai direction,between biow boxes. An example ot a dryer operating in accordance with theiast-ntentioned principie is described in US 6,014,8i8. As described in thatdocument upper and iower turning roiis are arranged in a drying box to makethe web travet verticaiiy through a number of verticai drying decks, and/oroooiing deoks between biow boxas, caiied “iet boxes" in US 61314318. A webposition controi unit 24; 124; 224; 324 of one of the types described in thepresent document with reference to Figs. Za to 5 oouid be arranged inside, orjust outside, of the housing ot a drying box ot a verticai web dryer to controithe iateral position of the web ieaving the vertioai web dryer.

Claims (17)

36 24

1. CLAih/iS i. Arrangement for drying ceiiuiose puip, the arrangement cornprising adrying box (22; 122; 222; 322), a web position controi unit (24; 124; 224; 324),which is operativa for controiiing the iaterai position of a web (44) of ceiiuiosepuip dried in the drying box (22; 122; 222; 322), and a web forwarding device(26), which is operativa for forwarding the web (44) of puip through the dryingbox and through the web position controi unit, c h a ra o t e r i s e d in the web position controi unit (24; 124; 224; 324)being arranged upstrearn, as seen with respect to the direction (T) offonrvarding the web (44), of the web forwarding device (28), and cornprising aguide roiier arrangement (54; 354) coniprising at ieast one guide roiier (66,62, 63; 366) and being operativa for deiivering a web (44) of puip, the iateraiposition of Which has been controiied, at an angie (B) of -45° to +45° to thehorizontai piane.

2. Arrangement according to ciaim f, wherein the guide roiierarrangement (54) comprises a first guide roiier (66) and a second guide roiier(62), with the second guide roiier (62) being iooated downstrearn of the firstguide roiier (60) as seen in the direction (T) of fonvarding the web (44).

3. Arrangernent according to any one of the preceding oiaints, whereinthe guide roiier arrangement (54; 354) is arranged inside a housing (34; 134;334) of the drying box (22; 122; 222).

4. Arrangement according to any one of the preceding ciairns, whereinthe drying box (22) corriprises at ieast one deck (46; 46) comprising biowboxas (42, 43; 47, 46) being operativa for biowing a gas towards the web(44), the guide roiier arrangement (54) being arranged in said dock (46; 46).

5. Arrangernent according to ciairn 4, wherein biow boxas (47, 48) arearranged in said at ieast one deok (46) both upstream and downstream ofsaid guide roiier arrangement (54).

6. Arrangernent according to any one of ciairns 4-5, wherein said deck(46) is inciuded in a cooiing zone (36) of the drying box (22), said cooiingzone (38) being operativa for cooiing the dried web (44). 18 3G

7. ?. Arrangement according to any one of the preceding ciaims, whereinthe drying box (122; 322) comprises at ieast one column of turning roiis (53)around which the web (44) of puip may be turned when being forvtIardedbetween decks (40; 46) inciuded in the drying box (122; 322), the guide roiierarrangement (54; 354) being arranged beiow said coiumn of turning roiis(53).

8. Arrangement according to any one of the preceding ciaims, whereinat ieast a portion of a free distance (FD) needed for the web (44) downstreamof the guide roiier arrangement (54; 354) is arranged inside a housing (34;134; 334) of the drying box (22g 122; 322).

9. Arrangement according to any one of ciaims 1-2, wherein the guideroiier arrangement (54) is arranged downstream of the drying box (234), asseen in the direction (T) of forwarding the web (44).

10. Arrangement according to any one of the preceding ciaims,wherein the web (44) is foivvarded directiy from the guide roiier arrangement(54; 354) to the web forwarding device (28), the path of the web (44) beingchanged iess than +/-“it3° in a vertical direction between the guide roiierarrangement (54; 354) and the web forwarding device (28).

11. Arrangement according to any one of the preceding ciaims,wherein the drying box (22g 122; 222; 322), the web position controi unit (24;124; 224; 324), and the web forwarding device (28) are aii mounted directiyon a common machine room fioor (80).

12. Arrangernent according to any one of the preceding ciaims,wherein the guide roiier arrangement (5-4; 354) is operativa for deiivering aweb (44) of puip, the iaterai position of which has been controiied, at an angie(B) of -30° to +30° to the horizontai piane.

13. A method of drying a ceiiuiose puip in an arrangernent cornprisinga drying box (22g 122; 222; 322), a web position controi unit (24; 124; 224;324), which is operativa for controiiing the iaterai position of a web (44) ofceiiuiose puip dried in the drying box (22; 122; 222; 322), and a webforwarding device (28), which is operativa for forwarding the web (44) of puipthrough the drying box and through the web position controi unit,characterised in forvvarding the dried puip web (44) to a guide roiier arrangernent (54;354) being inciuded in the web position controi unit (24; 124; 224; 324) andcomprising at ieast one guide roiier (60, 62, 63; 360), controiiing the iaterai position of the web (44) by means of the guideroiier arrangement (54; 354), and deiivering the web (44) from the guide roiier arrangement (54; 354) atan angle (B) of -45° to +45° to the horizontai piane.

14. A method according to ciaim 13, further cornbrising foryvarding theweb (44), after having oassed the guide roiier arrangement (54; 354), aiong afree distance (FD), aiong which the path of the web (44) being changed iessthan +l-10° in a verticai direction, at ieast a portion of said free distance (FD)being iocated inside a housing (34, 134; 334) of the drying box (22; 122; 322).

15. A method according to any one of ciaims 13-14, further comprisingforwarding the web (44) direotiy from the guide roiier arrangement (54; 354)to the web forwarding device (28), the path of the web (44) being changediess than +I-10° in a verticai direction when being fonivarded from the guideroiier arrangement (54, 354) to the Web forwarding device (28).

16. A method according to any one of ciaims 13-15, further comprisingforwarding the web (44) through the guide roiier arrangement (54) whichcomprises a first guide roiier (60) and a second guide roiier (62), with thesecond guide roiier (62) being iocated downstream of the first guide roiier (60)as seen in the direction (T) of forwarding the web (44).

17. A method according to any one of ciaims 13-16, wherein the web(44) is forwarded from the guide roiier arrangement (54g 354) to the webforwarding device (28) at a verticai distance (D) of Bess than 2 m above amachine room tioor (80) on which the guide roiier arrangement (54; 354) andthe web fonivarding device (28) are mounted.