JPS6353318B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a drying method during papermaking that can improve the uniformity of the moisture profile in the width direction of a sheet in a high-speed papermaking process, and a drying drum for papermaking.

[General explanation of paper making process]

Generally, sheets such as paper are manufactured through a papermaking process in which a water-containing sheet is formed from a suspension of pretreated sheet raw materials and then dried. There were problems that caused distortion and unstable product curl. Before explaining the conventional drying method and drying drum having such drawbacks, the entire papermaking process will be briefly explained. FIG. 4 is a schematic diagram of an example of a papermaking process. In pretreatment step 1 (the illustrations of each device are omitted), the sheet raw material is poured into water and stirred, and then passed through a centrifugal cleaner, a screen, and a decyl radar to remove foreign matter, air bubbles, etc. contained in the raw material. The sheet raw material suspension water obtained in this way is passed through the head box 2 to uniformly disperse the raw material fibers in the width direction, and then flowed onto the wire part 3, where most of the raw material fibers are dispersed using a foil, suction roll, vacuum roll, etc. The water is separated and formed into a sheet, and then the water is squeezed out by the pressure of the rolls of the press part 4 to make the moisture content of the sheet S about 55 to 60%. The water-containing sheet S thus obtained is passed through a smoother roll 5 and a dryer 6 to be dried. The dryer 6 is mainly composed of a large number of drying drums 7, and has a size press roll 8 in the middle, the part before it is called a pre-dryer 6a, and the part after it is called an after-dryer 6b, and in this example, there are 32 rolls of the former. The latter is composed of 14 drying drums 7, respectively. Steam is blown into each drying drum 7 to heat the drum surface, and the moisture in the water-containing sheet S in contact with it evaporates and dries. The sheet S, which has been dried to a moisture content of 4 to 5% at the outlet of the pre-dryer 6a, is coated with, for example, a starch liquid to improve the printability of the sheet S by a size press roll 8, and the moisture content is reduced to 35 to 40%. For example, 5
Dry to ~6%. Steam is blown into the drying drum 7 by sequentially dividing the pre-dryer 6a and after-dryer 6b into a plurality of sections from upstream to downstream, passing through one steam valve for each section, and then blowing steam into each drying drum in that section. The adjustment of the amount of steam supplied to the dry state of the sheet S is carried out by supplying steam to 7.
Pre-dryer 6a and after-dryer 6b
B/M total 9,1 installed after each exit
Pre-dryer 6a with a sheet moisture measurement of 0
This is done by adjusting the steam valves in the most downstream sections of the afterdryers 6b and 6b. Further, the drain generated in each drying drum 7 is sucked and discharged from each drying drum 7 in that section by the same suction force by one suction valve for each section. Sheet S dried in this way
After passing through the calender 11, it is given smoothness and the thickness is made uniform, and then the reel 12
It is wound up.

[Conventional technology]

The structure of the conventional drying drum 7' used in the dryer 6 in the papermaking process as described above will be explained with reference to FIG. 5, which is an explanatory diagram briefly showing one example thereof. In the figure, 13 is the drum body, and the steam blowing pipe 1
4, the drum surface 13a is heated and the sheet S in contact with it is dried. Reference numeral 15' denotes a drain discharge pipe provided at the axial center of the drum body 13 so as to protrude outside the drum body 13. 16
is a drain suction port, which is disposed close to the inner peripheral surface of the drum body 13 at a position near the center of the width of the drum body 13. Reference numeral 17 is a drain suction pipe that communicates the drain discharge pipe 15' and the drain suction port 16. Drain suction port 16 and drain suction pipe 17
and the drain discharge pipe 15' form one flow path,
It has traditionally been called a siphon. This siphon has a rotary type that is fixed to the drum body 13 and rotates with the rotation of the drum body 13, and a rotary type that is supported and fixed independently of the drum body 13 and remains fixed even when the drum body 13 rotates. There is a fixed type that does not rotate. The illustrated example is a rotary type, and in this case, a steam connection pipe 18' having a joint mechanism is attached to the protruding part of the drain discharge pipe 15', and a seal flange 19, a packing 20 and a spring 2 are installed.
1, the steam inlet 18a' and the drain outlet 18b' are separated by the sealing 22 pressed by the seal 22, and the steam inlet 18a' and the drain outlet 18b' are separated from each other.
The drum body 13, the steam blowing pipe 14, and the drain discharge pipe 15' are connected to the steam connecting pipe 1.
It is possible to rotate while maintaining the sealed state with 8'.
In addition to the illustrated example, drain suction pipe 17 and drain suction port 1
6 may be provided in the opposite direction, but even in this case, the two drain suction ports 16 are arranged at the same position close to the inner circumferential surface 13b of the drum body 13 and at the same position in the drum width direction. It is on the circumference. If the siphon is a rotary type, a convex portion is provided at the drain suction port 16 to provide a small distance from the drum body 13, and a spring 23 is installed on the opposite side of the drain suction port 16 and the drain suction pipe 17 as shown in the figure.
It is often fixed by its elasticity. When drying the wet sheet S using the conventional drying drum 7' as described above as each drying drum of the dryer 6 shown in FIG. Drain is easily sucked and discharged near the suction port 16, the thickness of the drain is thinner, and heat conduction is good, so the sheet S is easy to dry near the circumference of the drum surface corresponding to the position close to the drain suction port 16. Further, on both sides of the drum surface 13a of the drying drum 7', outside the paper width, there is no heat removal due to latent heat of evaporation, resulting in high temperatures that tend to overdry both side edges of the sheet S. Even if the food balance of the dryer 6 is adjusted optimally, the moisture profile of the sheet S is not uniform, and the center and both sides become overdry, resulting in R (the difference between the maximum and minimum moisture values in the sheet width direction). ) was on average around 1.5%. As a countermeasure against this, a dam ring 2 is installed on one or both sides of the interior of some drying drums 7' as shown in FIG.
4 to allow the drain on the side to remain without being sucked into the drain suction port 16, or by pasting a heat insulating material on the inner surface of the side, heat transfer on the side is made poor and the drum surface with the center part is prevented. The method of balancing the temperature, and the position of the drain suction port 16 with respect to the flow direction of the sheet S, using the drying drum 7', in which the drain suction port 16 is disposed at different positions left and right from the center of the drum width. Countermeasures have been taken, such as arranging the drums in a staggered manner to disperse the areas with high drum surface temperatures adjacent to the drain suction ports 16 in the width direction of the sheet S.

[Problems to be solved by the invention]

As a result of the above measures, when the papermaking speed is slow and the rotational speed of the drying drum 7' is low, the moisture profile of the drying sheet S is slightly improved and R is now within 1%, but it is still not sufficient. There is no improvement in drying efficiency. Moreover, the moisture profile pattern varies depending on paper width, basis weight, ash content,
It changes depending on various factors such as paper making speed, and these factors constantly change depending on the manufacturing plan.
In the various countermeasures described above, the countermeasures are fixed and cannot be modified in accordance with changes in the above-mentioned factors. In addition, the above method of arranging the positions of the drain suction ports 16 in a staggered manner allows the dryer 6 as a whole to disperse the high-temperature areas on the drum surface, but at the time of passing through each drying drum 7', the sheets S are locally dispersed. This causes thermal distortion and makes the product curl unstable. Furthermore, when the papermaking speed is high, such as 350 m/min or more, and the rotation speed of the drying drum 7' is high, the thickness of the drain in the drying drum 7' becomes uniform in the width direction of the drum due to centrifugal force, and the thickness of the drain is uniform on the drum surface. It was not possible to disperse the high temperature portions in the width direction of the sheet S. Conventional drying techniques during papermaking have had various problems as described above.

[Problem development process]

As a means for solving the above-mentioned problems, the present inventors have proposed that in a conventional drying drum 7', two or three sets of drain suction pipes 17 and drains are connected to one drain discharge pipe 15' at different positions in the width direction of the drum. A drying drum equipped with a suction port 16 was manufactured and examined. 6th
The figure shows three sets of drain suction pipes 17 and drain suction port 1.
6 is an explanatory view showing the main parts of the drain pipe 6 attached to one drain discharge pipe 15'. Inner peripheral surface 13b of the generally rotating drum body 13
A drain containing steam is pressed against the drain by centrifugal force. By exerting a suction force on the drain suction port 16 that overcomes this centrifugal force, the drain near the drain suction port 16 is sucked, but since the drain in a distant location is difficult to flow horizontally due to the centrifugal force, the drain suction port The thickness of the drain becomes thinner only in the vicinity of the drain suction port 16, and therefore the drum surface temperature increases, so even if three drain suction ports 16 are installed, the drain thickness will be lower than when there is only one drain suction port 16 as shown in Figure 5. The only thing that could be done was to suppress the localized high temperature of the drum surface and disperse it. However, in this drying drum, the drain suction force was applied to each drain suction port 16 through one control valve common to each drain suction port 16, so the suction was directed from the side closer to the suction source (drive side) to the side farther from the suction source (operation side). Since the force changes from strong to weak and the drain suctioned from the three suction ports 16 interferes with each other within one drain discharge pipe 15', the amount of drain sucked from the three drain suction ports 16 can be made uniform. It was difficult to do so. Furthermore, since the amount of drain generated varies depending on changes in the manufacturing plan such as paper width and sheet product configuration, it has been more difficult to equalize the amount of drain sucked from each drain suction port 16. The above effect is due to the slow paper making speed and drying drum 7'.
This is an effect that occurs when the rotation speed of is low,
When the paper making speed is slow and the rotational speed of the drying drum 7' is low, the drain suction port 16 is operated with a suction force that overcomes this centrifugal force.
Drain from a very limited area near 6 is sucked in, but the centrifugal force of the drain from far away areas makes it even in the width direction of the drum, so the drum surface temperature can be adjusted to the desired temperature distribution. I couldn't do it.

[Means to solve the problem]

Through the process of developing a means for solving the above-mentioned problems, the present inventors divided the drum in its width direction using partition rings, and applied suction force to each drain suction port 16 at a different position in the partitioned width direction. The present invention was completed based on the discovery that the temperature in the width direction of the drum can be controlled by adjusting the temperature. That is, one of the present inventions relates to a drying method during paper making to solve the above problems,
The wet sheet transferred through the wire part and the press part is guided to a dryer equipped with a number of drying drums into which steam is blown, and the sheet is dried while being brought into contact with the surface of each drying drum and moved at high speed. At this time, one or more drying drums are fixed with partition rings on the inner circumference of the drum, and drain suction ports are arranged circumferentially close to the drum inner circumferential surface at different positions in the width direction of the drum partitioned by the partition rings. The moisture profile in the width direction of the sheet is made uniform by adjusting the drain suction force for each group of suction ports arranged on the top and on the same circumference to make the temperature of the drum surface uniform. . Another aspect of the present invention relates to a papermaking drying drum suitable for carrying out the drying method during papermaking, in which a partition ring is fixed to the inner periphery of the drum body equipped with a steam blowing pipe. A drain suction port group configured for each inner circumference, with one or more drain suction ports arranged close to each of two or more inner circumferential surfaces at different positions in the width direction of the drum partitioned by a partition ring; , a drain discharge pipe having a multi-tube structure, which is provided at the axial center of the drum body so as to protrude outside the drum body and forms channels equal in number to the number of drain suction port groups; and each flow channel of the drain discharge pipe. A drain flow path is formed by the three types of members mentioned above, including a drain suction pipe that connects each drain suction port group with each other within the drum body, and the portion of the drain discharge pipe that protrudes outside the drum body connects each drain It is characterized in that a suction tube whose suction force can be adjusted is connected to each flow path. Hereinafter, the present invention will be explained in detail with reference to the drawings.
FIG. 1 is an explanatory diagram schematically showing the structure of an example of a drying drum for paper making according to the present invention, and FIGS. 2 and 3 show examples of the arrangement of the drying drum according to the present invention in a pre-dryer and an after-dryer, respectively. The explanatory diagram shown in FIG. 7 is a diagram showing the drying drum configuration of the afterdryer in the embodiment.

[Specific explanation of drying drum]

First, the drying drum 7'' for papermaking according to the present invention will be explained. In FIG.
4 is similar to the conventional drying drum 7'. In the present invention, the drum body 13
A partition ring 30 is fixedly installed on the inner periphery of the drum, and one or more drain suction ports are provided adjacent to each of the two or more drum inner peripheral surfaces 13b separated by the partition ring 30 and located at different positions in the drum width direction. 16 are arranged to constitute a drain suction port group for each partitioned inner circumferential surface 13b of the drum. Although one drain suction port group may be composed of a plurality of drain suction ports 16,
As shown in the figure, even one can be used. In the case of a plurality of them, it is preferable to arrange them at equal angular intervals with respect to the axis X. It is necessary to have a plurality of drain suction port groups, but two or three are common, and it is preferable that they are arranged at substantially symmetrical positions with respect to the center line Y of the width of the drum body 13. Multiple drying drums 7 of dryer 6
When there is a plurality of drying drums 7'' according to the present invention occupying a part of
There may be more than one drying drum 7''.The drain discharge pipe 15 used in the present invention has a multi-tube structure, and the innermost pipe and each pipe wall gap are designed to accommodate the number of drain suction port groups. Each flow path of the drain discharge pipe 15 and the drain suction port 16 of each drain suction port group are communicated with each other by a drain suction pipe 17.1
Drain suction port 16 with two or more drain suction port groups
In this case, all of these drain suction ports 16 are communicated with one flow path of the drain discharge pipe 15. Drain suction port 16 and drain suction pipe 1
7 and the drain discharge pipe 15 form a drain flow path, a so-called siphon. Example drying drum 7″
Now, each flow path and 2 of the drain discharge pipe 15 with a double pipe structure
1 each constituting each drain suction port group.
A siphon is formed by communicating the two drain suction ports 16 with a drain suction pipe 17, and a spring is attached to the extensible end 25a of each drain suction pipe 17 and the column 25 attached to the opposite side of the drain suction port 16. 23 is applied to the drain suction port 16 and the support column 2 against the inner circumferential surface 13b of the drum body 13.
By pressing the tip 25a of 5, the drain discharge pipe 15, drain suction pipe 17 and drain suction port 16 are removed.
A siphon consisting of is fixed to the drum body 13. A steam connecting pipe 18 having a joint mechanism is attached to the portion of the drain discharge pipe 15 that protrudes outside the drum body 13 and to the steam blowing pipe 14.
The steam connecting pipe 18 has one steam inlet 18a and drain outlets 18b, 18c, etc., equal to the number of drain passages in the drain discharge pipe 15.
0 and a seal ring 22 pressed by a spring 21, the steam inlet 18a and the plurality of drain outlets 18b, 18c, etc. are separated from each other and communicated with the inside of the drum body 13 and each drain passage of the drain discharge pipe 15. The drum body 13, the steam blowing pipe 14, and the drain discharge pipe 15 are rotatable while maintaining a sealed state with the steam connecting pipe 18. In the case of a fixed type siphon, the steam connecting pipe 18 except for the rotating and sliding part of the steam blowing pipe 14
The structure is easy because it can be fixed without rotating and sliding parts. Each drain outlet 18b, 1
A suction pipe 26 whose suction force can be adjusted by a regulating valve 27 is connected to each of the suction pipes 8c, etc., and a steam supply pipe 28 whose pressure can be adjusted by a regulating valve 29 is connected to the steam inlet 18a. Note that the drying drum 7'' according to the present invention may be provided with a dam ring 24 on the drum drive side in addition to the partition ring 30 that partitions the drain suction port group into two or more groups at different positions in the drum width direction. Good.This is because steam is generally blown in from the drive side, so the surface temperature of the drum on the drive side tends to rise.Furthermore, since there is a large space for the steam connection pipe 18, etc., the air temperature is not high and drying is promoted. This is because Dumb Ring 2
4 reduces the drum surface temperature by about 10° C., so it is usually sufficient to attach it to two or less drying drums 7''. The drying drum 7'' according to the present invention is constructed as described above.

[Specific explanation of drying method]

The drying method during papermaking according to the present invention, as explained in the general explanation section of the papermaking process with reference to FIG. A partition ring 3 is formed on the inner circumference of the drum body 13 in more than one drying drum 7.
0 is fixed, and drain suction port groups are provided at two or more different positions in the width direction of the drum partitioned by the partition ring 30, and the drain suction force is adjusted for each drain suction port group. This is a method of making the moisture profile of the sheet S uniform in the width direction by making the surface temperature uniform. In order to carry out such a drying method, it is most appropriate to use the drying drum (hereinafter sometimes referred to as improved drum) 7'' according to the present invention in accordance with the following installation standards. When correcting the non-uniformity of the moisture profile in the dryer 6a, if the pre-dryer 6a is composed of, for example, 32 drying drums 7, all drying drums 7 (the drums are shown) of the pre-dryer 6a as shown in FIG. The numbers in the circle are drum numbers) from the upstream side: sheet preheating section (10 pieces) A, evaporation section (15 pieces) B,
It is preferable to install the improved drum 7'' in the middle to the latter half of the whole, especially in the evaporation part B, since the improvement effect is large, and the number of drums is Six drums is appropriate, but it is best to determine this by looking specifically at the moisture profile of the sheet dried in the target pre-dryer 6a.The lower part of Figure 2 shows the arrangement of six improved drums 7''. Upper drum in Figure 2
The arrangement examples shown in correspondence with No. are also shown, and the uneven moisture profile occurring on the operation side H and the drive side D of the pre-dryer 6a and the two parts of each improved drum 7'' to correct this are shown. The positional relationship between two drain suction port groups G'' and one drain suction port group G' of another drying drum 7' is shown. (ii) When correcting the non-uniformity of the moisture profile in the afterdryer 6b, if the afterdryer 6b is composed of, for example, 14 drying drums 7, all drying drums 7 of the afterdryer 6b as shown in FIG.
(The numbers in the circles indicating the drums are the serial numbers of the drums attached consecutively to the pre-dryer.) Similarly to the pre-dryer 6a, from the upstream side, the sheet preheating section (2 drums) A', the evaporation section (8 drums) It can be divided into three groups: B' and seaming part (4 pieces) C'.The improved drum 7'' is the first half up to the center of the whole,
In particular, it is preferable to install it in the evaporation section B' because the improvement effect is large, and the appropriate number of drums is about 4, but specifically, the applicable afterdryer is 6.
It is best to determine this by looking at the moisture profile of the sheet dried in step b. The lower part of Figure 3 shows an example of the arrangement of four improved drums 7'', similar to the lower part of Figure 2.
It also shows the positional relationship between the uneven moisture profile and the drain suction port group G'' of each improved drum and the drain suction port group G' of the other drying drum 7'. In accordance with the above installation standards. After installing the improved drum 7'' and configuring the dryer 6, the sheet S may be dried according to a general papermaking process while sucking the drain from the improved drum 7'' as described below.

[Effect]

In the improved drum 7'', an independent drain discharge flow path is formed for each drain suction port group G'' at two or more different positions in the drum width direction, which are partitioned by the partition ring 30, The suction force can be adjusted for each drain suction port group G'' by the control valve 27. Therefore, the suction force of each drain suction port group G'' can be adjusted in response to the drain generation state due to changes in various factors such as the paper width. To uniformize the thickness of the drain in the width direction of the drum, and therefore the drum surface temperature, as quickly as possible by adjusting the suction force and distributing the drain at multiple positions in the width direction of the drum. I can do it. Dryer 6 with such an improved drum 7″
By drying the sheet S in one or more suitable locations of all drying drums 7, the moisture profile of the product can be significantly improved. In addition, the product profile can be improved by using a dam ring 24, which is conventionally provided on one or both sides of the inside of the drum body 13, in addition to the partition ring 30 that partitions the drain suction port group in the improved drum 7''. However, since the dam ring 24 fixes the thickness of the drain on the end side of the drum body 13 compared to the part where the internal dam ring 24 is provided, it cannot accommodate changes in the product configuration of the sheet, etc. Therefore, it is preferable to install the partition ring 30 at the position where the dam ring 24 is installed.

[Example, comparative example]

Drum width is 3750mm and pre-dryer 6a
is composed of a conventional drying drum 7' having one drain suction port 16 in the middle of the drum width, and the after-dryer 6b is similar to that shown in FIG. The following paper products were made using the papermaking process under the following conditions. Sheet width: 3000 to 3400mm (varies depending on product width) Drying temperature: around 120℃ (sheet) (3Kg/cm ² saturated steam used) Product composition: Basis weight 60Kg/m ² Thickness 84μm Paper making 1 (comparative example) Above Paper products (basis weight 60 Kg/m ² ) are processed at a speed of 800 using a dryer 6 consisting of conventional drying drums 7' in which all drying drums 7 of the after-dryer 6b have one drain suction port 16 in the middle of the drum width.
Dry at m/min. Paper Making 2 (Example) The above paper product (basis weight 60 kg/m ² ) was made at a paper speed of 800 m by a dryer 6 using an improved drum 7″ for four drying drums 7 as shown in FIG. 7 with an after dryer 6b. /min. Each of the four improved drums 7″ is equipped with two drain suction port groups.
Two of the improved drum 7″ drain suction ports
The interval between G'' is wider than the others, and a dam ring 24 is attached to the drive side, and a partition ring 30 is attached approximately in the middle of the interval between the drain suction port groups G''. The target value, maximum value, minimum value, and R of product moisture for each paper making of the moisture profile measured before winding on the reel 12 of each paper product obtained by each of the above paper making processes are shown in the following table.

[Table] From the table above, it can be seen that the moisture profile of paper products in a dryer configured only with the conventional drying drum 7', which has one drain suction port 16 in the middle of the drum width, as seen in Paper Making 1, is is a defective type M and has a large R of 1.3%.
Compared to these, when the improved drum 7'' according to the present invention is partially used and dried by the drying method according to the present invention, as seen in Paper Making 2, the moisture profile of the paper product is greatly improved, and the R The amount is extremely small at 0.3%, and the product is extremely stable without curling.

【effect】

As detailed above, if the drying drum for papermaking according to the present invention is used and dried by the drying method during papermaking according to the present invention, the paper width, basis weight, thickness, and other product configurations will change in the high-speed papermaking process. In response to changes in the condensate generation situation caused by this, the condensate suction force is changed in the width direction by the division ring that is divided corresponding to the condensate suction port group, and the condensate thin film stuck inside the drum is removed. By adjusting
Since the temperature can be made uniform in the width direction of the drying drum, the moisture profile of the sheet product can be improved, and the product curl can be stabilized, making it possible to form a good sheet product. It is also possible to improve drying efficiency.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing the structure of an example of a drying drum for papermaking according to the present invention, and FIGS. 2 and 3 show the arrangement of the drying drum for papermaking according to the present invention in a pre-dryer and an after-dryer, respectively. An explanatory diagram showing an example, Fig. 4 is a schematic diagram of an example of the papermaking process, Fig. 5 is an explanatory diagram briefly showing the structure of a conventional drying drum, and Fig. 6 shows three sets of drain suction pipes and drain suction ports. FIG. 7 is an explanatory diagram showing the main parts of the after-dryer attached to one drain discharge pipe, and FIG. 7 is a diagram showing the drying drum configuration of the after-dryer in the embodiment. 1... Pretreatment step, 2... Head box, 3
...Wire part, 4...Press part, 5...
...Smoother roll, 6...Dryer, 6a...
... Pre-dryer, 6b... After-dryer, 7... Drying drum, 7'... Conventional drying drum, 7''... Drying drum (improved drum) according to the present invention, 8... Size press roll, 9,10 ……
B/M meter, 11...Calender, 12...Reel, 13...Drum body, 13a...Drum surface, 13b...Drum inner peripheral surface, 14...Steam blowing pipe, 15, 15'...Drain discharge Pipe, 16...Drain suction port, 17...Drain suction pipe, 18,1
8'...Steam connection pipe, 18a, 18a'...Steam inlet, 18b, 18b'...Drain outlet, 18c...
Drain outlet, 19... Seal flange, 20...
Packing ring, 21...Spring, 22...Seal ring, 23...Spring, 24...Dam ring, 25...Strut, 25a...End, 26...Suction pipe, 27...Control valve, 28... Steam supply pipe, 2
9... Control valve, 30... Division ring, G'... Drain suction port group of conventional drying drum, G''... Drain suction port group of drying drum according to the present invention, S... Seat, X... Axis of the drying drum, Y...The center line of the drum width.

Claims (1)

[Claims] 1. A wet sheet transferred through a wire part and a press part is guided into a dryer equipped with a number of drying drums into which steam is blown, and brought into contact with the surface of each drying drum at high speed. When drying sheets while moving them, one or more drying drums have partition rings fixed on the inner periphery of the drum, and drain suction ports are installed at different positions in the drum width direction partitioned by the partition rings on the inner periphery of the drum. The moisture profile in the width direction of the sheet is made uniform by arranging them on the circumference close to the drum surface and adjusting the drain suction force for each group of suction ports on the same circumference to equalize the temperature of the drum surface. A drying method during paper making that is characterized by 2 A partition ring is fixedly installed on the inner periphery of the drum main body equipped with a steam blowing pipe, and 1 or more partition rings are arranged adjacent to each of two or more inner peripheral surfaces at different positions in the width direction of the drum partitioned by the partition ring. There is a drain suction port group configured for each inner peripheral surface with the above drain suction ports arranged, and a drain suction port group that is provided at the axial center position of the drum body and protrudes outside the drum body, and the number of drain suction port groups is equal to the number of drain suction port groups. From the above three types of members: a drain discharge pipe with a multi-tube structure forming a channel, and a drain suction pipe that communicates each flow path of the drain discharge pipe with each drain suction port group within the drum body. A drying drum for papermaking, characterized in that a drain flow path is formed, and a suction pipe whose suction force can be adjusted is connected to each drain flow path at a portion of the drain discharge pipe that protrudes outside the drum body. 3. The papermaking drying drum according to claim 2, wherein the drain suction port group, the drain discharge pipe, and the drain suction pipe rotate together with the drum body. 4. The papermaking drying drum according to claim 2, wherein the drain suction port group, the drain discharge pipe, and the drain suction pipe are fixed.