EP0368937B1 - A dryer section apparatus - Google Patents
A dryer section apparatus Download PDFInfo
- Publication number
- EP0368937B1 EP0368937B1 EP88909246A EP88909246A EP0368937B1 EP 0368937 B1 EP0368937 B1 EP 0368937B1 EP 88909246 A EP88909246 A EP 88909246A EP 88909246 A EP88909246 A EP 88909246A EP 0368937 B1 EP0368937 B1 EP 0368937B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- dryer
- web
- felt
- intermediate roll
- drums
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F5/00—Dryer section of machines for making continuous webs of paper
- D21F5/02—Drying on cylinders
- D21F5/04—Drying on cylinders on two or more drying cylinders
Definitions
- Such dryer section usually includes a plurality of heated dryer drums over which the formed web extends. As the web is brought into intimate contact with the heated outer surface of the dryer drums, the web is heated so that at least a portion of the moisture contained therein is removed from the web.
- the so-called "uni run” or “uno run” dryer sections typically include an upper and a lower tier of dryer drums.
- Each upper and lower tier comprise a pluraliry of heated, rotatable dryer drums.
- a felt extends in sinusoidal configuration alternately between dryer drums of the upper and lower tiers and the web is pressed into physical contact with the heated surface of each alternate dryer drum during passage through the dryer section.
- DE-A-1 931 922 published January 21, 1971 to Voith teaches a dryer section having an upper and a lower tier of dryers. However, although lower felts 7 partially extend around the lower tier of dryers, no felts extend around the upper dryers. Therefore, although DE-A-1 931 922 is the closest state of the art, the absence of an upper felt poses various runnability problems.
- the present invention overcomes the aforementioned problems associated with the prior art arrangement by the provision of a unique configuration of upper and lower dryer drums.
- the present invention provides a separate upper and lower felt with the upper felt extending alternatively around an upper dryer drum and an upper intermediate roll in sinusoidal configuration.
- the lower felt extends alternately between each lower dryer drum and a lower intermediate roll.
- the arrangement is such that each alternate intermediate roll of both the upper and lower intermediate rolls are wrapped by both the felt and the web.
- the web extends in open draw between each adjacent upper and lower dryer drum so that the web passes in intimate contact with the heated surface of each upper and lower dryer drum.
- the unsupported distance travelled by the web between adjacent upper and lower dryer drums is kept to a minimum.
- the objective of the present invention is to provide a dryer section apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an apparatus which not only enables the formed web to come into intimate contact with the heated surface of each dryer drum, but also minimizes the open draw between adjacent upper and lower dryer drums.
- the present invention relates to a dryer section apparatus and a method for drying a web extending therethrough.
- the apparatus includes a plurality of lower dryer drums and a plurality of upper dryer drums.
- the apparatus includes a lower felt which partially wraps each of the lower dryer drums of the plurality of lower dryer drums.
- the apparatus also includes a plurality of lower intermediate rolls with each lower intermediate roll being disposed between adjacent lower dryer drums such that each alternate lower intermediate roll guides both the web and the lower felt.
- An upper felt partially wraps each upper dryer drum of the plurality of upper dryer drums.
- the apparatus includes a plurality of upper intermediate rolls with each upper intermediate roll being disposed between adjacent upper dryer drums such that each alternate upper intermediate roll guides both the web and the upper felt so that the web is transferred in open draw between adjacent upper and lower dryer drums thereby minimizing the length of the open draw and inhibiting web flutter during transfer between upper and lower dryer drums.
- the lower felt presses the web into physical contact with the lower dryer drums such that when the lower dryer drums are heated, the web pressed against the lower drums is dried.
- the lower felt extends in sinusoidal configuration between each adjacent lower dryer drum and each lower intermediate roll.
- Each alternate lower intermediate roll which guides both the web and the lower felt is disposed adjacent to an upper intermediate roll which is partially wrapped by only the upper felt.
- Each of the alternate lower intermediate rolls is a vacuum roll.
- Each lower intermediate roll which is partially wrapped by the lower felt and the web and each upper intermediate roll which is partially wrapped by the upper felt and the web defines a pocket.
- a blow box is disposed within each of these pockets for ventilating each of the pockets and for removing boundary air entering into the pockets.
- the upper felt presses the web into physical contact with the upper dryer drums such that when the upper dryer drums are heated, the web pressed against the upper dryer drums is dried.
- the upper felt extends in sinusoidal configuration between each adjacent upper dryer drum and upper intermediate roll.
- Each alternate upper intermediate roll which guides both the web and the upper felt is disposed adjacent to a lower intermediate roll which is partially wrapped by only the lower felt and each alternate upper roll is a vacuum roll.
- the apparatus also includes a plurality of doctor blades with each blade cooperating with a corresponding dryer drum of the upper and lower dryer drums such that each blade contacts an unwrapped surface of each respective drum.
- the blades not only assist in stabilizing the web by restricting the influence of external air flows but also assist in directing a tail of the web during threading of the apparatus without the use of ropes.
- a duct is disposed adjacent to each lower intermediate roll partially wrapped only by the lower felt.
- the duct blows air through the lower felt for ventilating an adjacent dryer pocket defined between the upper and the lower felts.
- Ventilating means are disposed adjacent to each upper intermediate roll partially wrapped only by the upper felt.
- the ventilating means blows air through the upper felt for ventilating air from an adjacent dryer pocket defined between the upper and lower felts.
- the vacuum rolls are replaced by grooved rolls.
- Figure 1 is a side elevational view of a prior art dryer section showing an upper and a lower felt with the web extending in open draw for a considerable distance between adjacent upper and lower dryer drums.
- Figure 3 shows a so-called "squat type" dryer section in which the vertical distance between the upper and lower tier of dryer drums is reduced thereby reducing the unsupported distance travelled by the web between upper and lower dryer drums. This figure also shows that the distance between adjacent upper dryer drums is increased thereby reducing the number of dryer drums that may be provided within an available dryer section length.
- Figure 4 is a sectional view of a dryer section apparatus according to the present invention showing the "squat type" arrangement but minimizing the distance between adjacent upper dryer drums and minimizing the distance that the unsupported web travels between adjacent. upper and lower dryer drums, and
- Figure 5 is a similar view to that shown in figure 4 but shows the distance D6 as being the same as the distance D7.
- Figure 1 is a side elevational view of a prior art dryer section generally designated 10 showing an upper felt 12 and a lower felt 14 with the web W extending in open draw for a considerable distance between adjacent upper dryer drums 16 and 18 and lower dryer drum 20 respectively.
- the upper felt 12 does not extend around the lower drum 20 as in the "uni-run" type system but, rather, extends around an intermediate roll 22.
- the lower felt 14 extends in sinusoidal configuration around lower intermediate roll 24 and then around the lower dryer drum 20 such that the web W is disposed between the lower felt 14 and the outer surface 26 of the lower dryer drum 20.
- the lower felt 14 then extends around a further lower intermediate roll 28.
- Figure 4 is a sectional view of a dryer section apparatus 10C according to the present invention.
- Figure 4 shows the "squat type" arrangement but minimizes the distance D4 between adjacent upper dryer drums 16C and 18C. This arrangement also minimizes the distance D5 that the unsupported web WC travels between adjacent upper and lower dryer drums 16C and 20C respectively.
- the dryer section apparatus 10C shown in figure 4 is used for drying a web WC extending therethrough.
- the apparatus 10C includes a plurality of lower dryer drums 20C, 34 and 36 and a plurality of upper dryer drums 16C, 18C and 38.
- the apparatus 10C includes a lower felt 14C partially wrapping each lower dryer drum 20C, 34 and 36 of the plurality of lower dryer drums.
- a plurality of lower intermediate rolls 24C, 28C,40 and 42 are arranged such that each lower intermediate roll 24C, 28C,40 and 42 is disposed between adjacent dryer drums 20C, 34 and 36.
- the lower intermediate roll 28C is disposed between adjacent dryer drums 20C and 34 and the intermediate lower roll 40 is disposed between adjacent dryer drums 34 and 36 respectively.
- Each alternate lower intermediate roll 40 guides both the web WC and the lower felt 14C.
- An upper felt 12C partially wraps each upper dryer drum 16C, 18C and 38 of the plurality of upper dryer drums.
- a plurality of upper intermediate rolls 44,22C and 46 is arranged such that each upper intermediate roll 44, 22C and 46 is disposed between adjacent upper dryer drums.
- Upper roll 22C is disposed between dryer drums 16C and 18C and upper intermediate roll 46 is disposed between adjacent upper dryer drums 18C and 38 respectively.
- Each alternate upper intermediate roll such as roll 22C guides both the web WC and the upper felt 12C so that the web WC is transferred in open draw 48 between adjacent lower and upper dryer drums 20C and 16 respectively thereby minimizing the length D5 of the open draw 48 and inhibiting web flutter during transfer of the web between upper and lower dryer drums.
- Alternate lower intermediate roll 40 is disposed adjacent to the upper intermediate roll 46 which is partially wrapped by only the upper felt 12C.
- Each alternate lower intermediate roll of rolls 24C, 28C, 40 and 42 is a vacuum roll.
- Each lower intermediate roll such as 40 which is partially wrapped by the lower felt 14C and the web WC and each upper intermediate roll such as 22C which is partially wrapped by the upper felt 12C and the web WC defines pockets 50 and 51 respectively.
- a blow box generally designated 52 is disposed within the pocket 51 for ventilating the pocket 51 and for removing boundary air indicated by the arrow 54 entering into the pocket 51.
- the upper felt 12C presses the web WC into physical contact with the upper dryer drums 16C, 18C and 38 such that when the upper dryer drums 16C, 18C and 38 are heated, the web WC pressed against the upper dryer drums is dried.
- the upper felt 12C extends in sinusoidal configuration between each adjacent upper dryer drum 16C, 18C and 38 and upper intermediate rolls 44, 22C and 46.
- the dryer section apparatus 10C includes a plurality of doctor blades 56, 57, 58 and 59.
- Each blade 56 to 59 of the plurality of blades cooperates with a corresponding dryer drum 16C, 18C, 34 and 36 of the upper and lower dryer drums such that each blade 56 to 59 contacts an unwrapped surface 60, 61, 62 and 63 respectively of each drum 16C, 18C, 34 and 36.
- the blades 56 to 59 assist in stabilizing the web WC by restricting the influence of external air flows. Furthermore, the blades 56 to 59 assist in directing a tail (not shown) of the web during threading of the apparatus without the use ropes.
- the intermediate vacuum rolls are replaced by grooved rolls.
- Figure 5 is a side-elevational view of a dryer section apparatus which is the same as the dryer apparatus shown in figure 4 except in that the distances D8 and D9 are the same whereas in the arrangement of figure 4, D7 is greater than D6.
- D7 is greater than D6.
- a tail (not shown) of the web WC is guided between the lower felt 14C and the lower dryer drum 20C.
- the web is heated by direct contact with the outer surface 26C of the lower dryer drum 20C and passes in a short open draw D5 towards and around upper dryer drum 16C with the web WC being disposed between the upper felt 12C and the outer surface of the dryer drum 16C.
- the combined felt 12C and web WC extend around upper intermediate roll 22C so that the felt and web 12C and WC respectively together extend around the upper dryer drum 18C.
- the blow box 52 blows a curtain of air in a direction as shown by the arrow 74 such that any boundary air 54 entrained by the drum 16C is directed away from entry into the pocket 51.
- the rotational speed of the drums is increased to operational speed and it will be appreciated that the web extends around each of the dryer drums 20C, 16C, 18C, 34, 36 and 38 in intimate contact with the heated surfaces thereof for a considerable portion of the circumference of each dryer drum. Furthermore, the distance D5 that the web extends in open draw between adjacent upper and lower dryer drums is minimal thereby inhibiting the possibility of sheet flutter between adjacent dryer drums. Additionally, because of the aforementioned configuration, the number of upper and lower dryer drums that may be incorporated within a given dryer section length is increased due to the wrapping of both the web and felt around each alternate intermediate roll.
Abstract
Description
- This invention relates to a dryer section apparatus for drying a web extending therethrough. More particularly, the present invention relates to an apparatus having a plurality of lower dryer drums and a plurality of upper dryer drums.
- When a formed web of paper emerges from a press section of a papermaking machine, the formed web still contains a large percentage of water therein. Much of this water is removed from the formed web during passage of the web through a drying section of the papermaking machine. Such dryer section usually includes a plurality of heated dryer drums over which the formed web extends. As the web is brought into intimate contact with the heated outer surface of the dryer drums, the web is heated so that at least a portion of the moisture contained therein is removed from the web.
- The so-called "uni run" or "uno run" dryer sections typically include an upper and a lower tier of dryer drums. Each upper and lower tier comprise a pluraliry of heated, rotatable dryer drums. A felt extends in sinusoidal configuration alternately between dryer drums of the upper and lower tiers and the web is pressed into physical contact with the heated surface of each alternate dryer drum during passage through the dryer section. Although the aforementioned system provides support for the web by the felt during passage through the dryer section, such prior art systems suffer from the following disadvantages.
- First, the web is brought into physical contact with only each alternate heated dryer drum during passage through the dryer section because each alternate dryer drum includes the supporting felt disposed between the heated surface of the dryer drum and the web. Secondly, as the web extends around the dryer drum with the felt disposed between the web and the heated surface of the dryer drum, there existed the tendency for the web to be thrown by centrifugal force and for the web to be detached from the felt due to the wedge of air pressure at the ingoing nip.
- DE-A-1 931 922 published January 21, 1971 to Voith teaches a dryer section having an upper and a lower tier of dryers. However, although lower felts 7 partially extend around the lower tier of dryers, no felts extend around the upper dryers. Therefore, although DE-A-1 931 922 is the closest state of the art, the absence of an upper felt poses various runnability problems.
- The present invention overcomes the aforementioned problems associated with the prior art arrangement by the provision of a unique configuration of upper and lower dryer drums. Unlike the prior art "uni run" system, the present invention provides a separate upper and lower felt with the upper felt extending alternatively around an upper dryer drum and an upper intermediate roll in sinusoidal configuration. Similarly, the lower felt extends alternately between each lower dryer drum and a lower intermediate roll. The arrangement is such that each alternate intermediate roll of both the upper and lower intermediate rolls are wrapped by both the felt and the web. By such arrangement, the web extends in open draw between each adjacent upper and lower dryer drum so that the web passes in intimate contact with the heated surface of each upper and lower dryer drum. Furthermore, because of the aforementioned unique configuration, the unsupported distance travelled by the web between adjacent upper and lower dryer drums is kept to a minimum.
- Therefore, the objective of the present invention is to provide a dryer section apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an apparatus which not only enables the formed web to come into intimate contact with the heated surface of each dryer drum, but also minimizes the open draw between adjacent upper and lower dryer drums.
- Other objects and advantages of the present invention will be evident to those skilled in the art by consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings.
- The present invention relates to a dryer section apparatus and a method for drying a web extending therethrough. The apparatus includes a plurality of lower dryer drums and a plurality of upper dryer drums. The apparatus includes a lower felt which partially wraps each of the lower dryer drums of the plurality of lower dryer drums. The apparatus also includes a plurality of lower intermediate rolls with each lower intermediate roll being disposed between adjacent lower dryer drums such that each alternate lower intermediate roll guides both the web and the lower felt. An upper felt partially wraps each upper dryer drum of the plurality of upper dryer drums. The apparatus includes a plurality of upper intermediate rolls with each upper intermediate roll being disposed between adjacent upper dryer drums such that each alternate upper intermediate roll guides both the web and the upper felt so that the web is transferred in open draw between adjacent upper and lower dryer drums thereby minimizing the length of the open draw and inhibiting web flutter during transfer between upper and lower dryer drums.
- In a more specific embodiment of the present invention, the lower felt presses the web into physical contact with the lower dryer drums such that when the lower dryer drums are heated, the web pressed against the lower drums is dried. The lower felt extends in sinusoidal configuration between each adjacent lower dryer drum and each lower intermediate roll. Each alternate lower intermediate roll which guides both the web and the lower felt is disposed adjacent to an upper intermediate roll which is partially wrapped by only the upper felt. Each of the alternate lower intermediate rolls is a vacuum roll.
- Each of the lower intermediate rolls which guides both the web and the lower felt is disposed at a first distance relative to the upper intermediate roll which is partially wrapped by only the upper felt. Each of the lower intermediate rolls which are partially wrapped by the lower felt only is disposed a second distance relative to an adjacent upper intermediate roll partially wrapped by both the web and the upper felt. The arrangement is such that the second distance is the same as, or greater than the first distance.
- Each lower intermediate roll which is partially wrapped by the lower felt and the web and each upper intermediate roll which is partially wrapped by the upper felt and the web defines a pocket. A blow box is disposed within each of these pockets for ventilating each of the pockets and for removing boundary air entering into the pockets.
- The upper felt presses the web into physical contact with the upper dryer drums such that when the upper dryer drums are heated, the web pressed against the upper dryer drums is dried. The upper felt extends in sinusoidal configuration between each adjacent upper dryer drum and upper intermediate roll.
- Each alternate upper intermediate roll which guides both the web and the upper felt is disposed adjacent to a lower intermediate roll which is partially wrapped by only the lower felt and each alternate upper roll is a vacuum roll.
- The apparatus also includes a plurality of doctor blades with each blade cooperating with a corresponding dryer drum of the upper and lower dryer drums such that each blade contacts an unwrapped surface of each respective drum. The blades not only assist in stabilizing the web by restricting the influence of external air flows but also assist in directing a tail of the web during threading of the apparatus without the use of ropes.
- A duct is disposed adjacent to each lower intermediate roll partially wrapped only by the lower felt. The duct blows air through the lower felt for ventilating an adjacent dryer pocket defined between the upper and the lower felts.
- Ventilating means are disposed adjacent to each upper intermediate roll partially wrapped only by the upper felt. The ventilating means blows air through the upper felt for ventilating air from an adjacent dryer pocket defined between the upper and lower felts.
- In an alternative embodiment of the present invention, the vacuum rolls are replaced by grooved rolls.
- Although the present invention as described in the detailed description teaches intermediate rolls which are vacuum rolls, or grooved rolls, the present invention is not limited to the use of such rolls but includes pocket ventilation rolls, vented rolls, partially grooved rolls or the like. Although the present invention is described with certain particularity in the detailed description hereinafter, it will be appreciated by those skilled in the art that many modifications and variations of the basic concept of the present invention can be made without departing from the scope of the present invention as defined by the claims and that such variations and modifications fall within the scope of the present invention.
- Figure 1 is a side elevational view of a prior art dryer section showing an upper and a lower felt with the web extending in open draw for a considerable distance between adjacent upper and lower dryer drums.
- Figure 2 is a similar view to that shown in figure 1 but shows in the prior art arrangement of figure 1 how the upper dryer drums are brought close together in order to increase the number of dryer drums within a given available dryer section length.
- Figure 3 shows a so-called "squat type" dryer section in which the vertical distance between the upper and lower tier of dryer drums is reduced thereby reducing the unsupported distance travelled by the web between upper and lower dryer drums. This figure also shows that the distance between adjacent upper dryer drums is increased thereby reducing the number of dryer drums that may be provided within an available dryer section length.
- Figure 4 is a sectional view of a dryer section apparatus according to the present invention showing the "squat type" arrangement but minimizing the distance between adjacent upper dryer drums and minimizing the distance that the unsupported web travels between adjacent. upper and lower dryer drums, and
- Figure 5 is a similar view to that shown in figure 4 but shows the distance D6 as being the same as the distance D7.
- Similar reference characters refer to similar parts throughout the various figures.
- Figure 1 is a side elevational view of a prior art dryer section generally designated 10 showing an
upper felt 12 and alower felt 14 with the web W extending in open draw for a considerable distance between adjacentupper dryer drums lower dryer drum 20 respectively. As shown in figure 1, theupper felt 12 does not extend around thelower drum 20 as in the "uni-run" type system but, rather, extends around anintermediate roll 22. Similarly, thelower felt 14 extends in sinusoidal configuration around lowerintermediate roll 24 and then around thelower dryer drum 20 such that the web W is disposed between thelower felt 14 and theouter surface 26 of thelower dryer drum 20. The lower felt 14 then extends around a further lowerintermediate roll 28. - Figure 2 is a similar view to that shown in figure 1 but shows in the prior art arrangement of figure 1 how the
upper dryer drums - Figure 3 shows a so-called "squat type" dryer section in which the vertical distance DI between the upper and
lower tier lower dryer drums upper drums - Figure 4 is a sectional view of a dryer section apparatus 10C according to the present invention. Figure 4 shows the "squat type" arrangement but minimizes the distance D4 between adjacent upper dryer drums 16C and 18C. This arrangement also minimizes the distance D5 that the unsupported web WC travels between adjacent upper and lower dryer drums 16C and 20C respectively.
- More specifically, the dryer section apparatus 10C shown in figure 4 is used for drying a web WC extending therethrough. The apparatus 10C includes a plurality of
lower dryer drums lower dryer drum intermediate rolls intermediate roll adjacent dryer drums 20C and 34 and the intermediatelower roll 40 is disposed between adjacent dryer drums 34 and 36 respectively. Each alternate lowerintermediate roll 40 guides both the web WC and the lower felt 14C. An upper felt 12C partially wraps eachupper dryer drum 16C, 18C and 38 of the plurality of upper dryer drums. A plurality of upper intermediate rolls 44,22C and 46 is arranged such that each upperintermediate roll intermediate roll 46 is disposed between adjacentupper dryer drums 18C and 38 respectively. Each alternate upper intermediate roll such as roll 22C guides both the web WC and the upper felt 12C so that the web WC is transferred inopen draw 48 between adjacent lower andupper dryer drums 20C and 16 respectively thereby minimizing the length D5 of theopen draw 48 and inhibiting web flutter during transfer of the web between upper and lower dryer drums. - The dryer section apparatus 10C is arranged such that the lower felt 14C presses the web into physical contact with the
lower dryer drums lower dryer drums lower dryer drums lower dryer drum intermediate rolls - Alternate lower
intermediate roll 40 is disposed adjacent to the upperintermediate roll 46 which is partially wrapped by only the upper felt 12C. Each alternate lower intermediate roll ofrolls - The lower
intermediate roll 40 which guides both the web WC and the lower felt 14C is disposed at a first distance D6 relative to the upperintermediate roll 46 which is partially wrapped by only the upper felt 12C. Each of the lower intermediate rolls such as 28C which is partially wrapped by the lower felt 14C only is disposed a second distance D7 relative to an adjacent upper intermediate roll 22C partially wrapped by both the web WC and the upper felt 12C. The second distance D7 is greater than the first distance D6. - Each lower intermediate roll such as 40 which is partially wrapped by the lower felt 14C and the web WC and each upper intermediate roll such as 22C which is partially wrapped by the upper felt 12C and the web WC defines
pockets pocket 51 for ventilating thepocket 51 and for removing boundary air indicated by thearrow 54 entering into thepocket 51. - The upper felt 12C presses the web WC into physical contact with the upper dryer drums 16C, 18C and 38 such that when the upper dryer drums 16C, 18C and 38 are heated, the web WC pressed against the upper dryer drums is dried. The upper felt 12C extends in sinusoidal configuration between each adjacent
upper dryer drum 16C, 18C and 38 and upper intermediate rolls 44, 22C and 46. - Each alternate upper intermediate roll such as 22C which guides both the web WC and the upper felt 12C is disposed adjacent to a lower intermediate roll 28C which is partially wrapped by only the lower felt 14C. Each of the alternate upper rolls such as 22C is a vacuum roll.
- The dryer section apparatus 10C includes a plurality of
doctor blades blade 56 to 59 of the plurality of blades, cooperates with acorresponding dryer drum blade 56 to 59 contacts anunwrapped surface drum blades 56 to 59 assist in stabilizing the web WC by restricting the influence of external air flows. Furthermore, theblades 56 to 59 assist in directing a tail (not shown) of the web during threading of the apparatus without the use ropes. - As shown in figure 4, the apparatus 10C also includes a duct 64 disposed adjacent to each lower intermediate roll such as 28C partially wrapped only by the lower felt 14C. The duct 64 blows air (shown by the arrow 66) through the lower felt 14C for ventilating the
adjacent dryer pocket 50 defined between the upper and the lower felts 12C and 14C respectively. The apparatus 10C also includes ventilating means 68 disposed adjacent to each upper intermediate roll such as 18C partially wrapped only by the upper felt 12C. The ventilating means 68 blows air (as shown by the arrow 70) through the upper felt 12C for ventilating air from an adjacent dryer pocket 72 defined between the upper and the lower felts 12C and 14C respectively. - In an alternative embodiment of the present invention, the intermediate vacuum rolls are replaced by grooved rolls.
- Figure 5 is a side-elevational view of a dryer section apparatus which is the same as the dryer apparatus shown in figure 4 except in that the distances D8 and D9 are the same whereas in the arrangement of figure 4, D7 is greater than D6. By this arrangement, the felt wrap on
dryers 20D and 34D is increased. - In operation of the dryer section apparatus 10C when threading the apparatus, a tail (not shown) of the web WC is guided between the lower felt 14C and the lower dryer drum 20C. The web is heated by direct contact with the outer surface 26C of the lower dryer drum 20C and passes in a short open draw D5 towards and around upper dryer drum 16C with the web WC being disposed between the upper felt 12C and the outer surface of the dryer drum 16C. The combined felt 12C and web WC extend around upper intermediate roll 22C so that the felt and web 12C and WC respectively together extend around the upper dryer drum 18C. The
blow box 52 blows a curtain of air in a direction as shown by thearrow 74 such that anyboundary air 54 entrained by the drum 16C is directed away from entry into thepocket 51. The upper felt 12C after partially wrapping the drum 18C continues around upperintermediate roll 46 while the web WC continues travelling with the drum 18C and is guided by aid of thedoctor 57 into contact with the outer surface of thelower dryer drum 34. The tail is directed between the lower felt 14C and thedrum 34 and the felt 14C and the tail of the web extend together around lowerintermediate roll 40 and thereafter arounddrum 36. The tail of the web in open draw extends towards and aroundupper drum 38 between thedrum 38 and the upper felt 12C while the lower felt 14C extends around a further lowerintermediate roll 42. - When the web has been threaded, the rotational speed of the drums is increased to operational speed and it will be appreciated that the web extends around each of the dryer drums 20C, 16C, 18C, 34, 36 and 38 in intimate contact with the heated surfaces thereof for a considerable portion of the circumference of each dryer drum. Furthermore, the distance D5 that the web extends in open draw between adjacent upper and lower dryer drums is minimal thereby inhibiting the possibility of sheet flutter between adjacent dryer drums. Additionally, because of the aforementioned configuration, the number of upper and lower dryer drums that may be incorporated within a given dryer section length is increased due to the wrapping of both the web and felt around each alternate intermediate roll.
- The present invention provides a dryer section apparatus of compact configuration that enables the heating capability of each dryer drum within the section to be maximized. The arrangement also provides sufficient room for the inclusion therein of a doctor blade adjacent each individual dryer drum. Furthermore, the distance travelled by the unsupported web between adjacent dryer drums is minimized thereby reducing sheet flutter considerably.
Claims (15)
a blow box (52) disposed within each of said pockets (51) for ventilating each of said pockets and for removing boundary air entering into said pocket.
a plurality of doctor blades (56,57,58,59), each blade of said plurality of blades cooperating with a corresponding dryer drum of the upper and lower dryer drums such that each blade contacts an unwrapped surface of each respective drum.
a duct (64) disposed adjacent to each lower intermediate roll partially wrapped only by said lower felt (14C), said duct blowing air through said lower felt for ventilating an adjacent dryer pocket defined between said upper and lower felts.
ventilating means (68) disposed adjacent to each upper intermediate roll partially wrapped only by said upper felt, said ventilating means blowing air through said upper felt for ventilating air from an adjacent dryer pocket defined between said upper and lower felts.
guiding the web between a lower felt and a lower drum dryer;
directing the web in open draw towards and around an upper dryer drum such that the web is disposed between the upper dryer drum and an upper felt;
moving the combined web and upper felt around an upper intermediate roll and thereafter around a second upper dryer drum;
directing the upper felt around a second upper intermediate roll;
moving the unsupported web away from the second upper dryer drum towards and around a second lower dryer drum such that the web is disposed between the second lower dryer drum and the lower felt; and
thereafter moving the combined web and lower felt together around a second lower intermediate roll towards a third lower dryer drum such that the web is brought into intimate contact with the heated surface of each of the heated dryer drums and the unsupported distance travelled by the web between adjacent dryer drums is minimized.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT88909246T ATE79425T1 (en) | 1987-07-23 | 1988-06-13 | DRYING SECTION. |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB878717387A GB8717387D0 (en) | 1987-07-23 | 1987-07-23 | Dryer section apparatus |
GB8717387 | 1987-07-23 | ||
US07/110,405 US4835881A (en) | 1987-07-23 | 1987-10-19 | Dryer section apparatus |
US110405 | 1993-08-23 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0368937A1 EP0368937A1 (en) | 1990-05-23 |
EP0368937B1 true EP0368937B1 (en) | 1992-08-12 |
Family
ID=26292530
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP88909246A Expired - Lifetime EP0368937B1 (en) | 1987-07-23 | 1988-06-13 | A dryer section apparatus |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0368937B1 (en) |
JP (1) | JPH076156B2 (en) |
AU (1) | AU608386B2 (en) |
BR (1) | BR8807626A (en) |
FI (1) | FI89523C (en) |
WO (1) | WO1989001073A2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FI92420C (en) * | 1992-04-10 | 1994-11-10 | Valmet Paper Machinery Inc | Stabilizer for a paper web in a cylinder group contained in the drying portion of a paper machine |
DE4328555A1 (en) * | 1993-08-25 | 1994-03-31 | Voith Gmbh J M | Paper-making machine twin-blanket drying section - has structured gap between suction deflection rollers in upper row of cylinders and blanket path at lower row to reduce web path |
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---|---|---|---|---|
DE92297C (en) * | ||||
DE343644C (en) * | ||||
US3384973A (en) * | 1966-06-09 | 1968-05-28 | Svenska Flaektfabriken Ab | Ventilating dryers |
DE1931922A1 (en) * | 1969-06-24 | 1971-01-21 | Voith Gmbh J M | Drying device for drying a moist web, in particular the drying section of a paper machine |
JPS4515607Y1 (en) * | 1969-09-09 | 1970-06-30 | ||
US4483083A (en) * | 1982-08-18 | 1984-11-20 | Beloit Corporation | Drying and runnability for high speed paper machines |
FI68278C (en) * | 1983-03-01 | 1985-08-12 | Valmet Oy | FICKVENTILATIONSANORDNING FOER EN MAONGCYLINDERTORK I EN PAPPERSMASKIN |
FI68279C (en) * | 1984-03-22 | 1985-08-12 | Valmet Oy | FOERFARANDE OCH ANORDNING FOER ATT HINDRA PAPPERSBANAN ATT FLADDRA I TORKNINGSPARTIET AV EN PAPPERSMASKIN |
DE3623971A1 (en) * | 1986-07-16 | 1988-01-28 | Voith Gmbh J M | Drying section for drying a web of fibre material |
-
1988
- 1988-06-13 WO PCT/US1988/002019 patent/WO1989001073A2/en active IP Right Grant
- 1988-06-13 JP JP63508472A patent/JPH076156B2/en not_active Expired - Lifetime
- 1988-06-13 AU AU25512/88A patent/AU608386B2/en not_active Ceased
- 1988-06-13 BR BR888807626A patent/BR8807626A/en not_active IP Right Cessation
- 1988-06-13 EP EP88909246A patent/EP0368937B1/en not_active Expired - Lifetime
-
1990
- 1990-01-19 FI FI900306A patent/FI89523C/en not_active IP Right Cessation
Also Published As
Publication number | Publication date |
---|---|
EP0368937A1 (en) | 1990-05-23 |
FI89523C (en) | 1995-04-25 |
BR8807626A (en) | 1990-06-26 |
JPH076156B2 (en) | 1995-01-30 |
WO1989001073A2 (en) | 1989-02-09 |
AU608386B2 (en) | 1991-03-28 |
JPH03500790A (en) | 1991-02-21 |
FI89523B (en) | 1993-06-30 |
AU2551288A (en) | 1989-03-01 |
FI900306A0 (en) | 1990-01-19 |
WO1989001073A3 (en) | 1989-02-23 |
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