JPH0771443A - Hollow roll for travelling of raw material web - Google Patents

Abstract

PURPOSE: To provide a hollow roll for travelling on a material web, capable of reducing a difference between the diameter at both ends and the diameter at others when heated. CONSTITUTION: The temperatures of a calendar roll in use for machining a material web, a press roll and a hollow roll 1 in use for a drying cylinder at their ends are controlled. The roll 1 has an inner face heating device 20 and outer face heating devices 30, 30'. The inner face heating device 20 is arranged in the roll 1 for heating the inner face of the hollow roll 1 in a range smaller than the width of the material web 2 passing through the outer face of the roll 1. The outer face heating devices 30, 30' are arranged near both ends of the roll 1 for heating the outer face of the roll 1 at its ends.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calender roll used for processing a raw material web, a press roll and a hollow roll used as a drying cylinder.

[0002]

2. Description of the Related Art Some of the hollow rolls used as calender rolls, press rolls and drying cylinders for paper machines are equipped with a means for partially heating the hollow roll itself. There are various means. Then, in the processing of endless raw material web such as paper, by providing a plurality of heatable hollow rolls, a meandering path is provided, and by means of this meandering path, the raw material web is conveyed, The raw material web has been subjected to various treatments. In this case, the type of hollow roll with which the raw material web should come into contact and its contact angle differ depending on what kind of treatment is performed. Further, depending on the treatment, whether the raw material web directly contacts the hollow roll or whether the raw material web is indirectly supported by the hollow roll by interposing a screen or the like between the raw material web and the hollow roll varies.

[0003]

In the ordinary treatment, the raw material web does not come into contact with the heated hollow roll over its entire length, so that the temperature varies in the lengthwise direction of the hollow roll. In other words, in the region of the hollow roll where the raw material web comes into contact, heat is absorbed by the raw material web, whereas in the region where the raw material web does not come into contact (that is, both ends of the hollow roll), there is This is because relatively little heat is taken away through the rotation center axis or by radiation to the surrounding air.

Therefore, both ends of the hollow roll are overheated as compared with the contact region of the hollow roll which comes into contact with the raw material web, which causes the diameter of both ends of the hollow roll to increase. This means "ox bow (ox
-bow) effect ". In this case, the web is further dried at both ends as compared with the other parts of the hollow roll, and cracks may occur at both edges of the web.

A tensile force is applied along the longitudinal direction of the web in order to run the web. However, since the diameter of the end portion of the hollow roll becomes large, this tensile force is applied in the width direction of the web. There is a problem that it is scattered in. In this case, variations in the density of the web,
That is, while the density increases at both edges of the web,
It occurs that the density becomes smaller in other parts.

As described above, when the web is manufactured or processed by the heated hollow roll, the temperature distribution is not uniform in the length direction of the hollow roll, so that the quality of the web is deteriorated. . Such quality problems include thin edges at both ends of the web, excessive drying of both edges of the web and cracking, and excessive drying shrinkage at both edges of the web. It can be said that it becomes thicker. Furthermore, if a screen or the like is interposed between the raw material web and the hollow roll, the above-mentioned "ox-b (ox-b
Since the diameter of both ends of the hollow roll increases due to the "ow) effect", there is also a problem that the wear of the screen and the like is fast.

The present invention has been made to solve the above problems, and a raw material web capable of reducing the difference between the diameter of both ends of a heated hollow roll and the diameter of other portions thereof. An object is to provide a traveling hollow roll.

[0008]

In order to solve the above problems, the raw material web running hollow roll according to the present invention is a hollow roll designed to control the temperature at both ends thereof. The inner surface heating means for heating the inner surface of the hollow roll in a narrower range than the width of the raw material web passing on the outer surface of the hollow roll, and arranged near both ends of the hollow roll. At least one of the outer surface heating means for heating the outer surface of both ends of the hollow roll is provided.

[0009]

In the hollow roll according to the present invention, the amount of heat to be applied to the region where the raw material web of the hollow roll travels and both ends thereof is selectively controlled. Such control of the amount of heat is performed by means for heating the inner surface, which is arranged in a range narrower than the width of the raw material web wound around the hollow roll, and near the edge of the raw material web (that is, the end of the hollow roll). It is adapted to be performed by at least one of the arranged external surface heating means. Also, control of the amount of heat
It is also possible to use both the inner surface heating means and the outer surface heating means to heat both edge portions of the web to achieve a synergistic effect of the both.

The hollow roll according to the present invention is provided with means for controlling heating in order to compensate for the amount of heat taken by the raw material web as described above. This heating control means
It is designed to be able to selectively heat both ends of the hollow roll, including both ends of the hollow roll close to the center pin that is the axis of rotation of the hollow roll.
The temperature distribution on the surface of the hollow roll is made uniform over the length direction of the hollow roll.

[0011]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a side sectional view showing a hollow roll (hereinafter, referred to as a roll) 1 according to the present invention.
In the same figure, the central axis of the roll 1 is indicated by the symbol A. This roll 1 has a roll pin 10 that serves as a rotation center axis.
Installed on. An inner surface heating device 20 is arranged inside the roll 1 so as to be concentric with the surface of the roll 1. A supply line X is provided on the inner surface of the roll 1 and inside the roll pin 10, and thermal energy is supplied to the inner surface heating device 20 from the outside by the supply line X. As heat energy supplied to the inner surface heating device 20, steam heat, heat of heated oil, or heat of electricity can be used. Also, the inner surface heating device 20
Are arranged so as to be elongated along the axial direction of the roll 1, and the inside of the device 20 for heating the inner surface can be separately operated depending on the state of the roll 1 as shown by an arrow S. It is preferable that the area is provided by being divided into.

When this roll 1 is used, each of the divided insides of the apparatus 20 for heating the inner surface is divided according to the width W of the raw material web (hereinafter referred to as a web) 2 which is passed through the surface of the roll 1. Decide which of the zones will operate. Here, each area does not act on the entire width W of the web 2, and both edge portions (indicated by Δ) of the web 2 are not directly heated by the inner surface heating device 20. (However, it is indirectly heated by heat conduction). In FIG. 1, the edge of the web 2 running on the roll 1 is indicated by the symbol R. Also the symbol G
Indicates a boundary line of a region directly heated by the inner surface heating device 20, that is, a boundary line of the inner surface heating device 20. As shown in FIG. 1, by providing a difference Δ between the width W of the web 2 and the boundary line of the apparatus 20 for heating the inner surface, a problem that frequently occurs when the raw material web is heated, for example, the raw material web Excessive drying, improper shrinkage, abrasion, etc. can be reduced.

In the present embodiment, the inner surface heating device 20 is provided in the region where the web 2 is in contact with the roll 1 in an overlapping manner. However, the present invention is not limited to this, and the inner surface heating device 20 may be used. The amount of heat at both ends of the roll 1 may be controlled by heating the entire inner surface of the roll 1 by using a heat insulating material or a cooling device.

In the present embodiment, as shown in FIG. 1, the inner surface heating device 20 is arranged in a range narrower than the width W of the web 2 (that is, inside the edge portion Δ of the web 2 protruding from the inner surface heating device 20). In this way, both ends of the roll 1 can be prevented from being overheated. Therefore, the temperature distribution on the surface of the roll 1 can be made substantially uniform over the entire length of the roll 1. However, if the inner surface heating device 20 is used alone, the web 2
Both edge portions (shown by Δ in FIG. 1) of the boundary line G and the edge R
(The length of the portion between the two), that is, the temperature at both ends of the roll 1 is rather decreased, which may lead to deterioration of the quality of the raw material web.

Therefore, in the present invention, a device for heating the outer surface may be used in order to avoid the temperature drop at both ends. In this embodiment, two external heating devices 30, 3 are used.
0'is used. External heating device 30, 30 '
Are arranged near both ends of the roll 1 and near both end edges Δ of the web 2 traveling on the roll 1. The amount of heat supplied to the external heating device 30, 30 'is
It is selected according to the amount of heat supplied to the inner surface heating device 20. Therefore, the region heated by the outer surface heating device 30, 30 ′ is the same as the region heated by the inner surface heating device 20,
Both ends of the roll 1 partially overlap with each other.

It is preferable that the degree of heating by the outer surface heating devices 30 and 30 ′ becomes larger as the position is closer to the outside, that is, the roll pin 10 along the axial direction of the roll 1. Further, depending on the operating state of the roll 1, the outer surface heating devices 30 and 30 ′ may be arranged only inside the both end edges R of the web 2. Alternatively, the external surface heating device 30, 30 ′ may extend to the outside considerably longer than both end edges R of the web 2. For this purpose, long external surface heating devices 30, 30 'may be used, or a plurality of external surface heating devices 30, 30' may be provided.

External heating devices 30, 3 shown in FIG.
0'is arranged substantially parallel to the central axis A of the roll 1 (that is, in the direction of arrow Y). In addition, in FIG. 1, the outer surface heating devices 30, 30 ′ are provided below the roll 1.
Although the outer surface heating devices 30 and 30 ′ are provided around the roll 1, it is arbitrary. As described above, since the positions where the external surface heating devices 30 and 30 'are provided can be freely selected, it is particularly advantageous when a large number of rolls 1 are arranged and the web 2 travels in a zigzag manner. Further, although not shown, the external surface heating device 3
A heat supply unit such as a heated air supply unit is connected to 0 and 30 ', but as described above, the external surface heating device 3
This connection is easy because the positions where 0 and 30 'are provided can be freely selected.

In FIG. 1, the length of the arrow S'is made larger toward the outer side along the axial direction of the roll 1, but as described above, this is the degree of heating by the outer surface heating device 30, 30 '. Indicates that the larger the distance from the roll pin 1 along the axial direction of the roll 1, that is, the closer to the roll pin 10, the larger. Specifically, the degree of heating gradually increases from the inside of the web 2, and the degree of heating becomes constant outside the web 2. At the boundary line G, which is a portion that overlaps with the inner surface heating device 20, the amount of heat per unit length provided by the outer surface heating devices 30 and 30 ′ is equal to the outer surface heating device 30,
It is about half of the total output of 30 '. Then, in the portion deviated from the inner surface heating device 20, the amount of heat given by the outer surface heating device 30, 30 'increases linearly, and at the outer end of the outer surface heating device 30, 30' near the roll pin 10, the heat amount is changed. It corresponds to the total output of the external heating devices 30, 30 '. The amount of heat applied to the vicinity of the roll pin 10 is constant, and thus the temperature of the roll pin 10 is also constant. In order to achieve the above, a device for heating the inner surface 2
As is the case with 0 as indicated by the arrow S, the external surface heating devices 30, 30 'may also be divided by as indicated by the arrow S'to provide zones and enable each zone individually.

The outer surface heating device 30, 30 'may preferably be a heater utilizing an induction current, infrared rays, or a vortex current, or may use steam, heated air, or heated oil. The inner surface heating device 20 and the outer surface heating devices 30, 30 ′ may be of the same type or of different types.

Next, the characteristics of the roll according to the present invention and the characteristics of the conventional roll will be compared and described with reference to FIGS. 2 (a) to 2 (c) are other (conventional) devices that do not use the heating device 20, 30, 30 'shown in FIG.
The roll 1'is heated by the method and the web 2 is
2 shows a thermal state of the roll 1'in the vicinity of the edge R'when the roll is run. In this case, the roll body itself of the roll 1'is the same as the roll body of the roll 1 shown in FIG. 2D and 2E show ideal thermal states of the roll. In addition, (a) to (e) of FIG.
Shows a thermal state near the edge R when the web 2 is run by the roll 1 according to the present invention.

In FIG. 2A, the entire inner surface of the roll 1'is
In the heated state, the web 2 (virtually indicated by a chain double-dashed line
Is near the edge R'when the roll passes through the surface of the roll 1 '
Shows the thermal state of. The web 2 passes through as shown.
In the region, the heat quantity Q from the roll 1 '_PWill be robbed.
In addition, in FIG. 2, an edge R ′ virtually illustrated by a one-dot chain line
The right side of the roll overlaps the web 2 of the roll 1 '.
No, it shows the part that does not contact. From (a) of FIG.
It is relatively large in the area U where the roll 2 and the roll 2'are overlapped.
Calorie Q_PYou can see that has been robbed. Meanwhile, roll
1'web 2 is relatively small in non-overlapping area
Heat quantity Q _LOnly taken away. Heat loss Q in this part_LIs
This is due to heat conduction and heat radiation to the surrounding air. this
As a result, there is a large temperature difference near the end of the roll 1 '.
Jijiru

FIG. 2B shows the amount of heat Q _I ′ given to the roll 1 ′ when only the portion of the roll 1 ′ adapted to the width of the web 2 is heated. In this case, as shown in FIG. 2C, at a position slightly apart from the edge R ′ of the web 2, the distribution of the temperature T is almost the same on the left side and the right side of the edge R ′. ((C) in FIG. 2 shows the same portion as (a) and (b), that is, the change in the temperature T near the edge R ′ of the web 2.) However, when the roll 1'is heated over the entire width of the web 2 as described above, a large variation in the temperature T occurs at a position extremely close to the edge R'of the web. In this case, a difference in the diameter of the roll 1'is caused, which affects the quality of the raw material web.

FIG. 2D shows an ideal heat supply state in the vicinity of the edge R'of the web 2, that is, the heat quantity Q _A 'is selectively supplied only to the portion in contact with the edge R'and the web 2. Shows the state of being. 2E shows an ideal temperature distribution state, that is, a state in which a constant temperature T _O 'is distributed over the entire surface of the roll 1'. An object of the present invention is to perform ideal heat supply as shown in FIG. 2 (d) to achieve an ideal temperature distribution as shown in FIG. 2 (e).

The above-described problems described with reference to FIGS. 2A to 2C are caused by the heat control shown in FIGS. 3 and 4 using the roll 1 shown in FIG. Can be resolved.

FIGS. 3A to 3C show the thermal state of the roll 1 near the edge portion Δ of the web 2 shown in FIG. 1, respectively. FIG. 3A shows the amount of heat taken from the roll 1 by the web 2 similarly to FIG. 2A. Web 2
Since the amount of heat absorbed is also largely different between the left and right edges R of FIG. 3, (a) of FIG. 3 is the same as (a) of FIG.

However, according to the present invention, the device 20 for heating the inner surface is similar to the case of FIG. 2 in that the device 20 for heating the inner surface is arranged on the side opposite to the web 2 with the roll 1 interposed therebetween. It is directly heated by the boundary line G of the roll 1.
Since it is only the area inside in the axial direction, it is possible to prevent the influence of the heat Q _I by the inner surface heating device 20 from reaching the edge R of the web 2 as shown in FIG. 3B. it can. The amount of heat supplied from the inside to the surface of the roll 1 is, as shown in (b), the boundary line G from the inside in the axial direction.
Is constant until the vicinity of, but from the vicinity of the boundary G to the web 2
A curve that decreases toward the edge R of is drawn.

As a result, the temperature distribution on the surface of the roll 1 is
It becomes as shown in FIG. Since the heat loss is small on the right side of the edge R of the web 2, the low temperature portion is between the boundary line G and the edge R. Then, as shown in (d) of FIG. 3, the heat quantity Q _A sufficient for accurately compensating for this low temperature portion is set by the outer surface heating device 30, 30 ′.
, The ideal constant temperature T _O distribution can be obtained as shown in FIG.

FIG. 4 shows an example of the synergistic effect of the inner surface heating device 20 and the outer surface heating devices 30, 30 'of the roll 1 shown in FIG. In FIG. 4, the heat quantity given to the roll 1 by the inner surface heating device 20 up to the boundary line G is shown as Q _I , and the heat quantity given to the roll 1 by the outer surface heating device 30 or 30 ′ is shown as Q _A. There is. As shown in the figure, the area heated by the outer surface heating device 30 or 30 ′ partially overlaps the area heated by the inner surface heating device 20. The heat quantity Q _A gradually increases from the web 2 side, and at the boundary line G, the heat quantity Q _I
Is about half of the above, and the maximum output is reached at a position of about half of the edge portion Δ of the web 2. Rather than that, the edge R of the web 2
At a position close to, the heat quantity Q _A remains constant at the maximum output.

Although one embodiment of the present invention has been described above, the following may be adopted as another embodiment. For example, it is possible to further adjust the above calorific value correction curves by the inner surface heating device and the outer surface heating device depending on the properties of the raw material web and the operating state of the roll (including mechanical characteristics). In this case, the operating states of the inner surface heating device and the outer surface heating device can be dynamically adjusted in accordance with temperature changes on the outer surface of the roll and changes in the width of the raw material web in the operating initial state. It is also possible to control the temperature of the roll outer surface by adjusting the temperature of the inner heating device and the outer heating device while monitoring the temperature of the edge region of the web. It goes without saying that the above description is for facilitating the present invention and is not intended to limit the present invention, and various modifications can be made.

[0030]

According to the present invention, by heating the inner surface of the hollow roll in a range narrower than the width of the raw material web,
It is possible to prevent both end portions of the hollow roll, which takes in relatively little heat, from becoming overheated. As a result, the diameter of the end of the hollow roll becomes larger than the diameter of other parts, so-called "ox-bo (ox-bo)".
w) effects can be avoided. Therefore, the density of both end edges of the raw material web is different from that of other portions, the thickness of both end edges of the raw material web is different from that of other portions, cracks occur at both end edges, and the raw material web. It is possible to reduce the abrasion of the screen itself, the screen interposed between the raw material web and the hollow roll, and the like.

Further, by providing an outer surface heating means and controlling the temperature of both ends of the hollow roll by using the outer surface heating means and the inner surface heating means in combination, the hollow roller is heated only by the inner surface heating means. In this case, it is possible to prevent the temperature of both ends of the hollow roll from being lowered rather. Further, by dividing the inner surface heating means and the outer surface heating means, thereby providing separately operable areas, and selectively operating these areas, the hollow roll is partially selected and heated. It is possible to Thereby, an ideal temperature distribution, that is, a uniform temperature distribution can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view showing a hollow roll according to the present invention.

Figure 2 is a graph showing the thermal properties of the vicinity of the end portion of the case of using the conventional roll roll, (a) shows distribution of heat Q _P Q _L taken away, (b) is fed to the roll Shows the distribution of the heat quantity Q _I ', (c) shows the distribution of the temperature T,
(D) shows the ideal distribution of the heat quantity Q _A 'supplied to the roll, and (e) shows the ideal temperature T _O ' distribution.

3A and 3B are graphs showing the thermal characteristics near the end of the roll when the roll according to the present invention is used, where FIG. 3A shows the distribution of the heat quantity Q taken away, and FIG. The distribution of the heat quantity Q _I supplied to the roll is shown, (c) shows the distribution of the temperature T when heated only by the inner surface heating device,
(D) is the heat quantity Q _A supplied to the roll by the external heating device
(E) shows the distribution of the temperature T _O when the inner surface heating device and the outer surface heating device are used in combination.

FIG. 4 is a heat quantity Q _I supplied to the roll by the inner surface heating device when the end portion of the roll is simultaneously heated by the inner surface heating device and the outer surface heating device using the roll according to the present invention. 3 is a graph showing the distribution of the heat quantity Q _A supplied to the roll by the outer surface heating device.

[Explanation of symbols]

 2 Raw material web 10 Roll pin 20 Inner surface heating device (means) 30, 30 'External surface heating device (means) A Central axis R Edge of raw material web G Edge line of inner surface heating device W Raw material web width Q Calorie T Temperature Δ Edge

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Meinetsuke, Albrecht Germany, 89520 Heidenheim, Hans Holbein Schuttraße 39

Claims (6)

[Claims] 1. A hollow roll configured to control the temperature of both ends, wherein the hollow roll is arranged inside the hollow roll and is narrower than a width of a raw material web passing on an outer surface of the hollow roll. An inner surface heating means for heating the inner surface of the hollow roll, and at least one of an outer surface heating means arranged near both ends of the hollow roll for heating the outer surface of both ends of the hollow roll. A hollow roll for running a raw material web. 2. The both ends of the hollow roll are simultaneously heated by the inner surface heating means and the outer surface heating means to be temperature controlled.
The hollow roll described in 1. 3. The inner surface heating means and the outer surface heating means such that regions heated by the inner surface heating means and the outer surface heating means at least partially overlap each other at both ends of the hollow roll. The hollow roll according to claim 2, wherein the hollow roll is arranged. 4. Hollow roll according to claim 1, characterized in that the means for heating the inner surface are segmented and provided with zones which are individually operable. 5. Hollow roll according to claim 1, characterized in that the means for heating the outer surface are segmented and provided with zones which are individually operable. 6. The hollow roll according to claim 1, wherein the means for heating the outer surface is arranged parallel to the central axis of the hollow roll.