Heating roll for a corrugator

Abstract

 The present invention intends to provide a heating roll for use in a corrugator in which the lowering temperature for heating a paper web sheet can be effectively suppressed when condensate of heating fluid forms a liquid film. To this end, according to the present invention, the heating roll is arranged to include a shell (11) formed into a cylindrical shape having a hollow, applied with heat by a heat applying fluid medium (2) supplied into said hollow, contacted to the paper web sheet at the outer periphery of the sheet to heat the paper web sheet, while rotating along the conveying path for conveying the paper web sheet, and a plurality of heat transfer portions (15, 25, 35, 35A to 35K) provided on the inner wall (11a), having a height (H) which enables the heat transfer portion to be projected inwardly toward the shell axis. Even if condensate of the fluid (2) forms a liquid film (3a) covering the inner wall (11a) upon rotation of the shell (11), the heat transfer portions (15, 25, 35, 35A to 35K) project inwardly toward the shell axis and heat of said fluid (2) transfers to said shell (11) through the heat transfer portions (15, 25, 35, 35A to 35K).

Description

BACKGROUND OF THE INVENTION

1) Field of the Invention

[0001] The present invention relates to a heating roll of a corrugator for heating paper web sheets in a production process in which conveying paper web sheets are stuck with each other to form a corrugated paper sheet.

2) Description of the Related Art

[0002] FIGS. 10(a) and 10(b) are diagrams showing an example of a general arrangement of a heating roll which is used in a corrugator as a pre-heater, a corrugating roll, a pressure roll, a belt roll and so on for applying heat to a paper web sheet (single face corrugated paper sheet or a liner) before bonding is effected. FIG. 10(a) is a schematic cross-section as viewed from its front face (as viewed from the sheet conveying direction) and FIG. 10(b) is a cross-section taken along a line A1-A1 of the FIG. 10(a).

[0003] The heating roll (preheater roll) 110 shown in FIG. 10(a) is arranged to heat a paper web sheet while rotating in the conveying direction of the paper web sheet which is wound around the outer periphery thereof. The heating roll includes a cylindrical shell 11 supplied with steam 2 into the inner space thereof for heating the paper web sheet and shafts 12a and 12b supported by a pair of bearings which are provided at both the end portions of the shell 11.

[0004] Of the aforesaid shafts 12a and 12b, one shaft 12a is a pipe-like one and the steam 2 for heating the paper web sheet is supplied through the shaft 12a into the inner space of the shell 11. Also, a drain pipe 14 is inserted through the shaft 12a into the shell 11 so that condensate deriving from the steam (hereinafter referred to as drain) can be discharged from the shell 11 through the pipe 14 to the outside.

[0005] Meanwhile, in order for improving the productivity of the corrugated paper sheet, it is desirable for the rate of rotation of the heating roll to be set as high as possible. However, if the rate of rotation of the heating roll is too high, a centrifugal force will strongly act on the drain within the heating roll due to the rotation, with the result that a rimming water film will be formed on the inner wall of the heating roll. FIGS. 11(a) to 11(c) are schematic cross-sections of the heating roll as viewed from the side thereof. The mechanism of occurring the rimming water film will be briefly explained with reference to FIGS. 11(a) to 11(c). As shown in FIG.11(a), the drain 3 is left within the shell 11. When the shell 11 rotates at a high rate, the high speed rotation will cause the strong centrifugal force, which makes the drain 3 take a state as illustrated in FIG. 11(b). Then, as shown in FIG. 11(c), the drain 3 is formed into a film (rimming water film) 3a covering the inner wall 11a of the shell 11 entirely.

[0006] If the rimming water film 3a is formed on the inner wall 11a of the shell 11, the heat transfer between the steam 2 of the inner side of the rimming water film 3a (shell axis side) and the shell 11 is lowered, and the surface temperature of the shell 11 is lowered. For this reason, the temperature of the paper web sheet heated by the heating roll 110 is remarkably lowered as compared with a case in which the rimming water film 3a is not formed. Thus, unsatisfactory adhesion of the paper web sheets may occur due to the insufficient heat application. Therefore, if the higher rate rotation is requested, addition of the heating roll becomes necessary to secure a predetermined heat to the paper web sheet.

[0007] As a heating roller for suppressing the temperature lowering at the surface of a heating roller upon the rimming water film formation as described above, although not for use in a corrugator, a heating roller for use in a paper machine having spoiler bars is disclosed in USP 3,217,426 (Reference 1) and USP 4,195,417 (Reference 2), for example. Description will be made hereinafter on the structure of the heating roller of Reference 2, in particular, with reference to FIG. 12. In an arrangement of a heating roller 210, a plurality of spoiler bars, each of which is elongated in the roll axis direction, are arrayed on the inner wall of the shell 211 in the circumferential direction with a predetermined interval interposed therebetween. The spoiler bars 212 are made of magnet and hence fixed to the shell 211 as a magnetic material owing to the magnetic force thereof.

[0008] In the heating roller of the paper machine, the thickness of the rimming water film becomes about three to five millimeters. The aforesaid spoiler bar 212 causes turbulence to the rimming water film to bring about a turbulent flow so that heat transfer can be promoted between the drain and the roller inner wall. Thus, lowering of the roller surface temperature can be suppressed even if the rimming water film is formed.

[0009] However, the high rate driving is more and more requested aiming at the improvement of productivity in recent years, and with this high rate driving, the time period of contact between the heating roller and the paper web sheet becomes relatively short. As a consequence, satisfactory suppression of the roller surface temperature lowering is not available by the conventional technology such as one described above in which the turbulent flow is caused in the rimming water film.

SUMMARY OF THE INVENTION

[0010] The present invention is made in view of the above aspect. Therefore, it is an object of the present invention to provide a heating roll of a corrugator which can effectively suppress the lowering of the paper web sheet heating temperature even when condensate of heating fluid forms a rimming liquid film.

[0011] According to the present invention, in order to attain the above object, there is provided A heating roll for use in a corrugator provided to face a conveying path of paper web sheet and for heating said paper web in a production process in which conveyed paper web sheets are stuck to each other to form a corrugated paper sheet, said heating roll of the corrugator characterized by comprising a shell having a cylindrical shape with a hollow, applied with heat by heat applying fluid supplied into said hollow, contacted with said paper web sheet at an outer periphery of said shell to heat said paper web sheet while rotating along said conveying path for conveying said paper web sheet; andapluralityof heat transferportions each of which is provided on an inner wall of said shell, and even if condensate of said fluid forms a liquid film covering said inner wall upon rotation of said shell, height of each of which is set so that said heat transfer portion projects inwardly toward the shell axis compared with said liquid film; wherein heat of said fluid transfers to said shell through said heat transfer portion even if said liquid film is formed.

[0012] With the above arrangement, even if a liquid film is formed upon rotating the shell, the heat transfer portion can cause turbulent flow in the liquid film to promote the heat transfer from the condensate (liquid deriving from condensation of the heating fluid) to the shell. In addition, heat of fluid inside the liquid film conducts to the shell through the heat transfer portions. Accordingly, the temperature of the outer periphery of the shell can be prevented from being lowered, and moreover the lowering of temperature at which the sheet is heated can be suppressed. Thus, it becomes possible to protect the paper web sheets from adhesion failure therebetween which will be effected in the subsequent production step.

[0013] Furthermore, the amount of heat applied to the sheet by a single unit of heating roll can be secured. Therefore, the number of heating roll units requested to provide in the production stage can be decreased as compared with that of a conventional heating roll arrangement.

[0014] The heat transfer portion is desirably fixed to the shell.

[0015] With this arrangement, the heat can be effectively conducted from the heat transfer portion to the shell.

[0016] Each of said plurality of heat transfer portions may be a linear-shaped fin (which is elongated in the axial direction of said shell and whose height sufficiently larger than whose width in the circumferential direction of said shell), and a plurality of said linear-shaped fins may be provided on the inner wall of said shell with a predetermined interval interposed therebetween.

[0017] In this case, it is preferable that each of said fins may be divided into a plurality of fin portions arrayed in the axial direction of said shell with a space interposed therebetween at a predetermined axial position. Further, it is preferable that a ring-like member is attached to one end of said fin portion so that said ring-like member faces said space and takes an upright posture relative to said inner wall of said shell.

[0018] Alternatively, each of said plurality of heat transfer portions may be a ring-like fin (which is formed along the circumferential direction of said shell and whose height sufficiently larger than whose width in the axial direction of said shell), and a plurality of said ring-like fins maybe arrayed in the axial direction of said shell with a predetermined interval interposed therebetween.

[0019] Alternatively, each of said plurality of heat transfer portions maybe a projection (whose lengths in the axial direction and the circumferential direction of said shell are relatively small, respectively), and a plurality of said projections may be arrayed in the axial direction and the circumferential direction of said shell.

[0020] The heating roll is preferably provided with driving means for rotatively driving the shell.

[0021] With the above arrangement, particularly when the shell is rotatively driven at a high rate (the heating roll is rotated at a high rate), the paper web sheet can be free from excessive tension in the conveying direction owing to the rotational drive of the shell by the driving means. Further, if the revolving rate of the heating roll is kept constant regardless of the conveying speed of the paper web sheet, it becomes possible to suppress the fluctuation in the heat transfer between the fluid and the shell.

[0022] Further, the shell may be desirably divided into a plurality of units in the axial direction, and each of the units may be desirably supplied with the heating fluid independently, whereby an amount of heat applied to the sheet material can be adjusted for each unit.

[0023] With the above arrangement, the amount of heat applied to the paper web sheet can be varied in accordance with the posit ion of the sheet width direction (shell axial direction).

[0024] In this case, it is preferable that each of the plurality of units is equipped with driving means for rotatively driving the unit.

[0025] According to the present invention, there is provided a heating roll for use in a corrugator provided to face a conveying path of paper web sheet and for heating said paper web in a production step in which conveyed paper web sheets are stuck to each other to form a corrugated paper sheet, said heating roll of the corrugator characterized by comprising a shell having a cylindrical shape with a hollow, applied with heat by heat applying fluid supplied into said hollow, contacted with said paper web sheet at an outer periphery of said shell to heat said paper web sheet, and rotating along said conveying path for conveying said paper web sheet; a plurality of heat transfer portions, each of which is provided on an inner wall of said shell so as to project toward the shell axis side, is elongated in the axial direction of said shell and is divided at a predetermined position in the axial direction of said shell.

[0026] In this case, it is preferable that the drain pipe is inserted into the shell so that the tip end thereof faces the inner wall of the shell at the space between the divided portions of the heat transfer portion.

[0027] According to the above arrangement, the heat transfer portion extending in the shell axis direction is divided into the predetermined position in the shell axis direction, and the drain pipe is inserted into the shell so that the tip end thereof faces the inner wall of the shell at the space between the divided portions of the heat transfer portion. Therefore, the drain pipe can be free from interference with the heat transfer portion which rotates integrally with the shell, and the drain can be discharged from the shell.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 

FIG. 1 (a) is a diagram showing a heating roll of a corrugator as a first embodiment of the present invention in which there is shown a schematic cross-section as viewed from the front side thereof;

FIG. 1 (b) is a diagram showing a heating roll of a corrugator as a first embodiment of the present invention in which there is shown a schematic diagram corresponding to the cross-section taken along a line A2 - A2 of FIG. 1 (a) wherein the heating roll is placed in a halting state;

FIG.1 (c) is a diagram showing a heating roll of a corrugator as a first embodiment of the present invention in which there is shown a schematic diagram corresponding to the cross-section taken along a line A2 - A2 of FIG. 1 (a) wherein the heating roll is placed in a rotating state;

FIG. 2 (a) is a diagram showing a heating roll of a corrugator as a second embodiment of the present invention in which there is shown a schematic cross-section as viewed from the front side thereof;

FIG. 2 (b) is a diagram showing a heating roll of a corrugator as a second embodiment of the present invention in which there is shown a schematic diagram corresponding to the cross-section taken along a line A3 - A3 of FIG. 2 (a) wherein the heating roll is placed in a rotating state;

FIG. 3 (a) is a diagram showing a heating roll of a corrugator as a third embodiment of the present invention in which there is shown a schematic cross-section as viewed from the front side thereof;

FIG. 3 (b) is a diagram showing a heating roll of a corrugator as a third embodiment of the present invention in which there is shown a schematic diagram corresponding to the cross-section taken along a line A - A of FIG. 3 (a) wherein the heating roll is placed in a rotating state;

FIG. 4 (a) is a diagram showing a heating roll of a corrugator as a fourth embodiment of the present invention in which there is shown a schematic cross-section as viewed from the front side thereof;

FIG. 4 (b) is a diagram showing a heating roll of a corrugator as a fourth embodiment of the present invention in which there is shown a schematic diagram corresponding to the cross-section taken along a line A4 - A4 of FIG. 4 (a) wherein the heating roll is placed in a rotating state;

FIG. 4 (c) is a diagram showing a heating roll of a corrugator as a fourth embodiment of the present invention in which there is shown a schematic diagram corresponding to the cross-section taken along a line A5 - A5 of FIG. 4 (a) wherein the heating roll is placed in a rotating state;

FIG. 4 (d) is a diagram showing a heating roll of a corrugator as a fourth embodiment of the present invention in which there is shown a schematic diagram as viewed on an arrow A6 in FIG. 4 (b);

FIG. 5 (a) is a diagram showing a structure of a modification of a proj ection according to the fourth embodiment of the present invention in which there is shown a schematic diagram corresponding to FIG. 4 (d);

FIG. 5 (b) is a diagram showing a structure of a modification of a proj ection according to the fourth embodiment of the present invention in which there is shown a cross-section taken along a line A7-A7 of FIG. 5 (a);

FIG. 6 (a) is a diagram showing a structure of a modification of a proj ection according to the fourth embodiment of the present invention in which there is shown a schematic diagram corresponding to FIG. 4 (d);

FIG. 6 (b) is a diagram showing a structure of a modification of a proj ection according to the fourth embodiment of the present invention in which there is shown a cross-section taken along a line A8-A8 of FIG. 6 (a);

FIG. 7 (a) to FIG. 7 (e) are diagrams respectively showing a modified arrangement of projections according to the fourth embodiment of the present invention;

FIG. 8 is a diagram showing a heating roll of a corrugator as a fifth embodiment of the present invention in which there is shown a schematic cross-section as viewed from the front side thereof;

FIG. 9 is a diagram showing a heating roll of a corrugator as a sixth embodiment of the present invention in which there is shown a schematic cross-section as viewed from the front side thereof;

FIG. 10 (a) is a diagram showing a general example of an arrangement of a conventional heating roll in which there is shown a schematic cross-section as viewed from the front side thereof;

FIG. 10 (b) is a diagram showing a general example of an arrangement of a conventional heating roll in which there is shown a cross-section taken along a line A1 to A1 of FIG. 10 (a) ;

FIG. 11 (a) to FIG. 11 (c) are schematic cross-sectional diagrams of a heating roll as viewed from the side thereof to which reference is made for explaining a mechanism of forming a rimming water film; and

FIG. 12 is a diagram showing an example of an arrangement of a conventional heating roll inwhich illustrated is a schematic cross-section as viewed from the side thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Embodiments of the present invention will be hereinafter described with reference to drawings.

(1) First embodiment

[0030] FIGS. 1(a) to 1(c) are diagrams showing a heating roll of a corrugator as a first embodiment of the present invention. FIG.1 (a) is a schematic cross-section as viewed from the front side thereof, FIG.1 (b) is a schematic diagram corresponding to the cross-section taken along a line A2 - A2 of FIG.1 (a) wherein the heating roll is placed in a halting state, and FIG. 1 (c) is a schematic diagram corresponding to the cross-section taken along a line A2 - A2 of the FIG.1 (a) wherein the heating roll is placed in a rotating state. Components corresponding to those described as the aforesaid conventional technology are attached with the same reference numerals and they will not be described in detail.

[0031] Similarly to the conventional heating roll 110 described with reference to FIGS. 10(a) and 10(b), a heating roll 10 of the present embodiment is utilized as a preheater for pre-heating a paper web sheet ( single-faced corrugated paper sheet or a liner) before gluing, a corrugating roller and a pressure roller or a belt roller for use in a corrugator. This heating roll 10 is comprised of a cylindrical shell 11 having a hollow and a pair of shaft portions 12a and 12b. The shaft portion 12a is disposed at one end of the shell 11 and the shaft portion 12b is disposed at other end of the shell 11. The shaft portion 12a and 12b are rotatively supported through bearings 13 respectively. Of the shaft portions 12a and 12b, one shaft portion 12a is a pipe shaped one so that steam for heating the paper web sheet (fluid for heating) 2 can be supplied through the shaft portion 12a into the shell 11. The shell 11 can heat the paper web sheet while rotating in the direction in which the paper web sheet wound around the shell 11 is conveyed.

[0032] On the inner wall 11a of the heating roll 11, there are provided a plurality of fin portions 15a and 15b each of which elongates in the shell axial direction (hereinafter sometimes referred to as a width direction or a CD direction), has a height dimension H sufficiently higher than the width (length along the shell circumferential direction) W and has a large ratio of surface to the volume thereof. This heating roll 10 is different from the aforesaid conventional heating roll 110 and 210 in the above point.

[0033] The shell 11 can be regarded as one having on its inner wall 11a a plurality of elongated fins 15, eachof which is composed of the aforesaid pair of fin portions 15a and 15b arrayed along the CD direction with a predetermined space interposed therebetween, arrayed around the entire roll inner wall 11a with a predetermined interval placed in the roll circumferential direction. Further, each of the aforesaid elongated fins 15 can be regarded as one divided into a plurality of fin portions (in this case two fin portions) 15a, 15b at a predetermined position in the CD direction.

[0034] In this case, the fin portions 15a and 15b are integrally fixed to the inner wall 11a (so as to achieve intimate contact thereto) by welding.

[0035] FIG. 1(b) is a diagram showing the heating roll in a halting state. Steam 2 supplied into the shell 11 is utilized for heating the paper web sheet running in contact with the outer periphery of the shell 11 and condensate of the steam 2 becomes drain 3. When the heating roll 10 is placed in the rotating state shown in FIG. 1(c), the drain 3 forms a rimming water film (liquid film) 3a covering the entire inner wall 11a owing to a centrifugal force of the rotation.

[0036] Each of the fin portionsfins 15a and 15b is arranged to have the height sufficiently higher than the thickness t of the rimming water film 3a. That is, the tip end of each fin portions 15a and 15b can be projected above the rimming water film 3a so that the fin portions 15a and 15b can be reliably contacted to the saturated steam 2 inside the rimming water film 3a(on the side of the roll axis). With this arrangement, even if the heating roll 10 is revolved at a high rate (i.e., upon the high rate driving of the corrugator) and the rimming water film 3a is formed on the inner wall 11a of the shell and the steam 2 is surrounded by the rimming water film 3a, the heat of the saturated steam 2 can be effectively transferred through each fin portions 15a and 15b to the shell 11.

[0037] Further, the rimming water film 3a placed between the fin portions 15a or between the fin portions 15b will be brought into a turbulent state owing to the sandwiching state of the fin portions 15a or 15b. As a consequence, the heat conducting rate between the drain 3 and the fin portions 15a and 15b will be improved and the heat of the drain 3 can be effectively recovered.

[0038] In the FIGS.1 (b) and 1 (c), the mounting pitch of the fin portions 15a and 15b along the roll circumferential direction is relatively wide for convenience of illustration. However, it is preferable that the sumof circumferential direction length of areas at which the fin portions 15a and 15b are mounted is longer than the sum of circumferential direction length of areas at which no fin is mounted.

[0039] In this case, the inner diameter Di of the shell 11 is set to 674mm and the rimming water film 3a will have a thickness t of about 0.5 to 1 mm. The fin portions 15a and 15b are set to have the height H of 44mm (corresponding to 6.5% of the inner diameter Di of the shell 11). Thus, the height H is set to be sufficiently high relative to the thickness t of the drain water film 3a. In this way, it is preferable for the fins 15a, 15b to have the height H of about 6% of the inner diameter Di of the shell 11. Further, the fin portions 15a, 15b are set to have a width W of 12mm in the roll circumferential direction.

[0040] As shown in FIG. 1 (a) , the drain pipe 14 is inserted into the shell 11 so that the tip end thereof (drain suction opening) faces the inner wall 11a at a portion of the shell 11 between the fin portions 15a and 15b. Therefore, the drain pipe 14 can be free from interference with the fin portions 15a and 15b which will be rotated together with the shell 11.

[0041] The heating roll of the corrugator as the first embodiment of the present invention is constructed as described above. Therefore, the following effects and advantages can be expected.

[0042] That is, even if the rimming water film 3a is formed on the shell inner wall 11a upon the high rate rotation of the heating roll 10, turbulent flow can be caused in the rimming water film 3a and the heat of the rimming water film 3a can be effectively transferred to the shell 11. Moreover, the fin portions 15a and 15b mounted on the inner wall 11a of the shell can effectively conduct the heat of the saturated steam 2 inside the rimming water film 3a to the shell 11. Therefore, the paper web sheet can be satisfactorily heated even when the heating roll is rotated at a high rate, the amount of heat to be applied to the paper web sheet can be secured without additionally providing the heating roll, and bonding the paper web sheets carried out in the subsequent production stage can be stably performed.

[0043] Further, since the fin portions 15a and 15b are integrally fixed to the shell inner wall 11a by welding, the heat transfer between the fins 15a, 15b and the shell 11 can be effectively performed.

(2) Second embodiment

[0044] FIGS. 2 (a) and 2(b) are diagrams showing a heating roll of a corrugator as a second embodiment of the present invention. FIG.2 (a) is a schematic cross-section as viewed from the front side thereof, and FIG. 2 (b) is a schematic diagram corresponding to the cross-section taken along a line A3 - A3 of FIG.2 (a) wherein the heating roll is placed in a rotating state. Components corresponding to those described above are attached with the same reference numerals and they will not be described in detail.

[0045] As shown in FIGS. 2 (a) and 2 (b) , the heating roll 10A of the present embodiment differs from the aforesaid heating roll 10 of the first embodiment shown in FIGS. 1(a) and 1(b) in that a dam ring 16a and 16b shaped into a ring-like member is intimately attached to the shell inner wall 11a.

[0046] The dam rings 16a and 16b are attached within the shell 11 so that they take a substantially upright posture (including a complete upright posture) relative to the shell inner wall 11a.

[0047] The dam rings 16a and 16b are attached to the inner wall 11a so that the rings can close the divided faces of fins 15. That is, the damring 16a is intimately attached to the end (divided face of fin 15) on the center side in the CD direction of the fin portion 15a which is disposed on the left side in FIG. 2 (a) and the dam ring 16b is intimately attached to the end (divided face of fin 15) on the center side in the CD direction of the fin portion 15b which is disposed on the right side in FIG. 2 (a).

[0048] In other words, the couple of straight fin portions 15a and 15b elongated in the CD direction are arrayed in the CD direction so that a space S is interposed therebetween at a predetermined position in the CD direction, the dam ring 16a is attached to the shell inner wall 11a so as to abut against the end of each fin 15a facing the aforesaid space S, and the dam ring 16b is attached to the shell inner wall 11a so as to abut against the end face of each fin 15b facing the aforesaid space S.

[0049] The heating roll of the corrugator as the second embodiment of the present invention is constructed as described above. Therefore, the following effects and advantages can be expected. That is, if the shell 11 is vibrated in the up-and-down direction upon rotation, then fluctuation is caused in the distance between the suction opening of the drain pipe 14 and the shell inner wall 11a, and fluctuation is also caused in the amount of absorbed by the drain pipe 14. However, owing to the dam ring 16a, it becomes possible to keep substantially constant the thickness t of the drain water film 3a on the outer side relative to the dam ring 16a in the CD direction (i.e., the left side in FIG. 2(a)). And owing to the dam ring 16b, it becomes possible to keep substantially constant the thickness t of the drain water film 3a on the outer side relative to the dam ring 16b in the CD direction (i.e., the right side in FIG. 2(a).

[0050] When the heating roll 10A is rotated, vibration will be caused in the drain 3 between the fin portions 15a (or the fin portions 15b), leading to turbulent flow in the drain 3. At this time, if the thickness t of the drain water film 3a reaches a specific thickness, then the drain 3 between the fin portions 15a (or the drain 3 between the fin portions 15b) are brought into a resonance mode. As a result, the aforesaid turbulent flow is more promoted, the heat transfer between the drain 3 and the fin portions 15a and 15b is more effectively performed, and the paper web sheet can be heated at a higher temperature.

(3) Third embodiment

[0051] FIGS. 3 (a) and 3(b) are diagrams showing a heating roll of a corrugator as a third embodiment of the present invention. FIG.3 (a) is a schematic cross-section as viewed from the front side thereof, and FIG. 3 (b) is a schematic diagram corresponding to the cross-section view taken along a line A - A and the view on arrow A of the FIG. 3 (a) (the shaft portion 12a and the drain pipe 14 are not illustrated) wherein the heating roll is placed in a rotating state. Components corresponding to those described above are attached with the same reference numerals and they will not be described in detail.

[0052] While in the above-described respective embodiments a plurality of the straight shaped fins 15a and 15b elongated in the CD direction are arrayed in the circumferential direction of the shell 11, the heating roll 10B of the present embodiment has a plurality of ring-like fins (heat transfer portion) 25 arrayed in area covering overall width of the shell 11 with a predetermined interval interposed there between in the CD direction as shown in FIG. 3(a) and FIG. 3(b). Each of the ring-like fins 25 is formed to have a height H sufficiently larger than the width (length along the CD) direction W1 or the thickness t of the drain water film 3a, and shaped into a ring extending along the shell inner wall 11a.

[0053] The heating roll of the corrugator as the third embodiment of the present invention is constructed as described above. Therefore, effects and advantages can be expected such that heat of the steam 2 inside the drain water film 3a can be transferred to the shell through the fins 25 which project toward the shell axial side relative to the drain water film 3a. Accordingly, the shell 11 can satisfactorily heat the paper web sheet and the paper web sheets can be free from bonding failure.

(4) Fourth embodiment

[0054] FIGS. 4(a) to 4(d) are diagrams showing a heating roll of a corrugator as a fourth embodiment of the present invention. FIG. 4 (a) is a schematic cross-section as viewed from the front side thereof, FIG. 4 (b) is a schematic diagram corresponding to the cross-section taken along a line A4 - A4 of FIG. 4 (a) wherein the heating roll is placed in a rotating state, FIG. 4 (c) is a schematic diagram corresponding to the cross-section taken along a line A5 - A5 of FIG. 4 (a) wherein the heating roll is placed in a rotating state, and FIG. 4 (d) is a schematic diagram as viewed on an arrow A6 in the FIG. 4 (b). Components corresponding to those described above are attached with the same reference numerals and they will not be described in detail.

[0055] The heating roll 10C of the present embodiment is constructed as shown in FIGS. 4 (a) to 4 (c). While in the above respective embodiments the heat transfer portions are arranged as straight shaped fins 15 elongated in the CD direction or the fins 25 formed into a ring-shape, the heat transfer portion of the present embodiment is composed of a dot-shaped projection 35 having relatively small dimensions in the CD direction and in the shell circumferential direction. The projections 35 are arrayed on the overall shell inner wall 11a so as to avoid locally biased placement.

[0056] In this case, as shown in FIGS. 4 (b) to 4 (d) , each of the projections 35 is formed into a columnar shape and attached to the shell inner wall 11a so that the axis thereof stands vertically with respect to the shell inner wall 11a. FIGS. 4(b) and 4(c) are diagrams respectively showing cross-sections of the roll taken along the cross-sectional planes adjacent to each other in the CD direction in which groups of the projections 35 are involved, respectively. As will be understood from the diagrams, the placement of the projections in the plane of FIG. 4(b) is shifted by half the pitch in the shell circumferential direction with respect to the placement of the projections in the plane of FIG. 4(c) which neighbors that of FIG. 4(b). That is, all of the projections 35 are arrayed in a staggered relationship. Of course the arrangement of the projections 35 is not limited to the staggered relationship.

[0057] The heating roll of the corrugator as the fourth embodiment of the present invention is constructed as described above. Therefore, effects and advantages can be expected such that heat of the steam 2 inside the drain water film 3a can be conducted to the shell 11 through the projections 35 which project toward the shell axial side relative to the drain water film 3a. Accordingly, the shell 11 can satisfactorily heat the paper web sheet and the paper web sheets can be prevented from unsatisfactory bonding to each other.

[0058] While in the above-described embodiment the projection 35 is formed into a columnar shape, the shape of the projection 35 may not be limited thereto but the projection may be formed into a shape of a projection 35A shown in FIGS. 5(a) and 5(b) or that of a projection 35B shown in FIGS. 6 (a) and 6(b), for example. FIGS. 5 (a) to 6 (b) are set of diagrams showing modified structures of the projection. FIG. 5(a) and FIG. 6(a) are schematic diagrams corresponding to FIG. 4(d). FIG. 5(b) is a cross-section taken along a line A7-A7 of FIG. 5 (a), and FIG. 6 (b) is a cross-section taken along a line A8-A8 of FIG. 6(a).

[0059] As shown in FIGS. 5(a) and 5(b), the projection 35A is formed into a cylindrical shape having a hollow in the inside thereof, and the drain 3 can be kept in the hollow 35Aa. Further, as shown in FIGS. 6(a) and 6(b), the projection 35B has a cylindrical shape similarly to the projection 35A, but the projection 35B additionally has provided at the tip end (the end on the shell axis side) of its main body portion 35Ba a ceiling portion 35Bb having a ring-shape extending toward the cylinder axis side of the main body portion 35Ba. Owing to the ceiling portion 35Bb, compared to projection 35A, increase of a contact area to the steam 2 and a higher performance in heat conductivity from the steam 2 to the shell 11 will be available.

[0060] The projections 35A and 35B are attached to the shell inner wall 11a so that the axes thereof keep an upright posture relative to the shell inner wall 11a.

[0061] Further, the shape of the projection or arrangement of the projections may be arranged as shown in FIGS. 7(a) to 7(e) (in FIGS. 7(a) to 7(e), the shell inner wall 11a is illustrated as if it is a plane surface for convenience of illustration). FIGS. 7(a) to 7(c) show examples in which each of the proj ections has a rectangular cross-section and stands on the shell inner wall 11a with a rectangle posture inclined with respect to the shell circumferential direction. Of these examples, the example shown in FIG. 7(a) is one in which arrays of projections 35B and 35B adjacent to each other in the CD direction have a rectangle posture of the same inclination, the example shown in FIG. 7(b) is one in which arrays of projections 35C and 35D adj acent to each other in the CD direction have rectangle postures of inclinations symmetry with respect to the center line thereof, and the example shown in FIG. 7(c) is one in which projections 35E and 35F adjacent to each other in the CD direction and projections 35G and 35H adj acent to each other in the CD direction have rectangle postures of inclinations symmetry with respect to the center line thereof. In the example of FIG. 7(c), projections 35E and 35G adjacent to each other in the shell circumferential direction and projections 35F and 35H adjacent to each other in the shell circumferential direction have postures of inclinations symmetry with respect to the center line thereof.

[0062] FIG. 7(d) shows an example of placement of projections 35J in which each of the projections 35J has a rectangular shape having a side extending in the CD direction longer than a side extending in the shell circumferential direction. FIG. 7(e) shows an example of a staggered arrangement of projections 35K in which each of the projections 35K has a rectangular shape having a side extending in the shell circumferential direction longer than a side extending in the CD direction.

(5) Fifth embodiment

[0063] FIG. 8 is a diagram showing a heating roll of a corrugator as a fifth embodiment of the present invention in which there is shown a schematic cross-section as viewed from the front side thereof. Components corresponding to those described above are attached with the same reference numerals and they will not be described in detail.

[0064] A heating roll 10D of the present embodiment is constructed as shown in FIG. 8. The arrangement of the heating roll 10D has an arrangement similar to that of the heating roll 10C of the aforesaid fourth embodiment, and has additionally provided driving means 17 for rotatively driving the heating roll main body composed of the shell 11 and the shaft portions 12a and 12b. The driving means 17 is composed of a motor 17a, gears 17b and 17c. The gear 17b is fixed to the driving shaft of the motor 17a. The gear 17c is meshed with the gear 17b and fixed to the shaft 12a of the heating roll 10D.

[0065] The shape and the arrangement of the projections 35 of the present embodiment may be replaced with those shown in FIGS. 5(a) to 7(e) similarly to the above-described fourth embodiment.

[0066] The heating roll of the corrugator as the fifth embodiment of the present invention is arranged as described above. Therefore, if the driving means 17 drives the shell 11 to rotate in the running direction of the paper web sheet, the paper web sheet wound around the heating roll 10D can be free from excessive tension in the conveyed direction of the sheet upon a high rate rotation. Moreover, the heating roll 10D may be kept constant in the rotation speed thereof regardless of the running speed of the paper web sheet so that the state of the drain reserved within the shell can be made stable. Thus, fluctuation of the heat conducting rate between the drain 3 and the shell 11 can be suppressed and the performance of heat application to the paper web sheet can be stabilized.

(6) Sixth embodiment

[0067] FIG. 9 is a diagram showing a heating roll of a corrugator as a sixth embodiment of the present invention in which there is shown a schematic cross-section as viewed from the front side thereof. Components corresponding to those described above are attached with the same reference numerals and they will not be described in detail.

[0068] As shown in FIG. 9, a heating roll 10E of the present embodiment is composed of a plurality of (in this case, a couple of) cylindrical units 11A and 11B having the same diameter arrayed coaxially with each other in the CD direction. In other words, the shell 11 is divided into the plurality of units 11A and 11B arrayed in the CD direction.

[0069] Each of the units 11A and 11B is rotatably supported by bearings 13 at the shaft portions 12a and 12b attached to both the ends of the unit. The units 11A and 11B are engaged with the driving means 17 for rotatively driving the units 11A and 11B, respectively.

[0070] Each of the units 11A and 11B has a cylindrical shape having a hollow therein and steam 2 is supplied into the unit through the shaft portion 12a having a pipe-shape independently. The drain pipe 14 is inserted through the shaft portion 12a into the unit 11A, 11B, whereby drain can be discharged through the drain pipe 14.

[0071] The aforesaid shaft portion 12a is connected with a steam supplying pipe not shown in the FIG. 9 and a steam regulator valve is attached with the steam supplying pipe. By independently controlling the steam valve, the pressure of the steam to be supplied to each unit 11A and 11B, and consequently, the amount of heat to be applied from each unit 11A and 11B to the paper web sheet can be independently adjusted.

[0072] Similarly to the above-described fourth embodiment, the projections 35 are arranged based on the staggered relationship in each of the units 11A and 11B. Therefore, the cross-section taken along a line A9-A9 of the unit 11A and the cross-section taken along a line A12-A12 of the unit 11B become similar to FIG. 4 (b). Further, the cross-section taken along a line A10-A10 of the unit 11A and the cross-section taken along a line A11-A11 of the unit 11B become similar to one illustrated in FIG. 4(c).

[0073] The shape and the arrangement of the projections 35 of the present embodiment may be replaced with those shown in FIGS. 5(a) to 7(e) similarly to the above-described fourth embodiment.

[0074] The heating roll of the corrugator as the sixth embodiment of the present invention is constructed as described above. Therefore, similarly to the aforesaid fifth embodiment, when the respective units 11A and 11B are rotatively driven, the rate of rotation of the units 11A and 11B may be kept constant so that the fluctuation of the heat conducting rate between the drain 3 and the shell 11 is suppressed. Moreover, the amount of heat applied to the paper web sheet on the respective units 11A and 11B arrayed in the CD direction can be independently adjusted and the profile along the CD direction of temperature for applying heat to the paper web sheet can be adjusted.

(7) Other disclosure

[0075] While several embodiments of the present invention have been described above, the present invention is not limited to the above embodiments but various changes and modifications can be effected without departing from the gist of the present invention.

[0076] For example, while for the above respective embodiments description has been made on examples in which the fins 15, fins 25, projections 35, 35A to 35K are attached on the shell inner wall 11a, a way for providing the heat transfer portion on the shell inner wall 11a is not limited thereto but the shell inner wall (raw material) may be subjected to grinding work so that the heat transfer portion can be formed integrally with the shell. Alternatively, the heat transfer portion may be integrally cast with the shell to form a unitary body, if possible.

[0077] As described above, the fifth embodiment is particularly shown as an example having the driving means for rotatively driving the shell 11 together with the heating roll 10C of the fourth embodiment, the driving means may be provided on the heating rolls 10, 10A, 10B of the first to third embodiments.

[0078] While in the above-described embodiments the heat transfer portions to be provided on the shell inner wall 11a are the fins extending in the CD direction, the fins extending in the shell circumferential direction or dot like projections, the heat transfer portions may be composed of a mixture of the fins extending in the CD direction and the dot-like projections, or a mixture of the fins extending in the shell circumferential direction and the dot-like projections, for example.

[0079] Furthermore, the shapes, respective dimensions, the mounting pitches and so on of the heat transfer portions may not be limited to the examples illustrated in respective diagrams but they are properly varied or changed depending on various conditions which are determined by the diameter of the shell, the temperature and pressure of the heating fluid, and so on.

Claims

1. A heating roll for use in a corrugator provided to face a conveying path of paper web sheet and for heating said paper web in a production process in which conveyed paper web sheets are stuck to each other to form a corrugated paper sheet, said heating roll of the corrugator characterized by comprising:

a shell (11) having a cylindrical shape with a hollow, applied with heat by heat applying fluid (2) supplied into said hollow, contacted with said paper web sheet at an outer periphery of said shell to heat said paper web sheet while rotating along said conveying path for conveying said paper web sheet; and

a plurality of heat transfer portions (15, 25, 35, 35A to 35K), each of which is provided on an inner wall (11a) of said shell (11), and even if condensate of said fluid (2) forms a liquid film (3a) covering said inner wall (11a) upon rotation of said shell (11), height of each of which is set so that said heat transferportion (15, 25, 35, 35A to 35K) projects inwardly toward the shell axis compared with said liquid film (3a);

   wherein heat of said fluid (2) transfers to said shell (11) through said heat transfer portion (15, 25, 35, 35A to 35K) even if said liquid film (3a) is formed.

2. A heating roll for use in a corrugator according to Claim 1, characterized in that said heat transfer portions (15, 25, 35, 35A to 35K) are fixed to said shell (11).

3. A heating roll for use in a corrugator according to Claim 1 or 2, characterized in that
   each of said plurality of heat transfer portions is a linear-shaped fin (15) which is elongated in the axial direction of said shell (11) and whose height (H) sufficiently larger than whose width (W) in the circumferential direction of said shell (11) and
   plurality of said linear-shaped fins (15) are arrayed in the circumferential direction of said shell (11) with a predetermined interval interposed therebetween.

4. A heating roll for use in a corrugator according to Claim 3, characterized in that
   each of said fins is divided into a plurality of f in port ions (15a, 15b) arrayed in the axial direction of said shell with a space (S) interposed therebetween at a predetermined axial position, and
   a ring-like member (16a, 16b) is attached to one end of said fin portion (15a, 15b), so that said ring-like member (16a, 16b) faces said space (S) and takes an upright posture relative to said inner wall (11a) of said shell (11).

5. A heating roll for use in a corrugator according to Claim 1 or 2, characterized in that
   each of said plurality of heat transfer portions is a ring-like fin (25) which is formed along the circumferential direction of said shell (11) and whose height (H) sufficiently larger than whose width (W1) in the axial direction of said shell (11) and
   plurality of said ring-like fins (25) are arrayed in the axial direction of said shell (11) with a predetermined interval interposed therebetween.

6. A heating roll for use in a corrugator according to Claim 1 or 2, characterized in that
   each of said plurality of heat transfer portions is a projection (35, 35A to 35K) whose lengths in the axial direction and the circumferential direction of said shell (11) are relatively small, respectively and
   a plurality of saidprojection (35, 35A to 35K) are arrayed in the axial direction and the circumferential direction of said shell (11).

7. A heating roll for use in a corrugator according to any one of Claims 1 to 6, characterized by comprising driving means (17) for rotatively driving said shell (11).

8. A heating roll for use in a corrugator according to any one of Claims 1 to 6, characterized in that
   said shell (11) is divided into a plurality of units (11A, 11B) arrayed in the axial direction, each of the units (11A, 11B) is supplied with said heating fluid (2) independently, and an amount of heat applied to said paper web sheet can be adjusted for each unit (11A, 11B).

9. A heating roll for use in a corrugator according to Claim 8, characterized in that
   each of said plurality of units (11A, 11B) is equipped with driving means (17) for rotatively driving said unit.

10. A heating roll for use in a corrugator provided to face a conveying path of paper web sheet and for heating said paper web in a production process in which conveyed paper web sheets are stuck to each other to form a corrugated paper sheet, said heating roll of the corrugator characterized by comprising:

a shell (11) having a cylindrical shape with a hollow, applied with heat by heat applying fluid (2) supplied into said hollow, contacted with said paper web sheet at an outer periphery of said shell (11) to heat said paper web sheet, and rotating along said conveying path for conveying said paper web sheet; and

a plurality of heat transfer portions (15) , each of which is provided on an inner wall (11a) of said shell (11) so as to project toward the shell axis side, is elongated in the axial direction of said shell (11) and is divided at a predetermined position in the axial direction of said shell (11).

11. A heating roll for use in a corrugator according to Claim 10, comprising a drain pipe (14) inserted into said shell (11) for discharging drain from said shell (11) and inserted into said shell (11) so that the tip thereof faces the inner wall (11a) of said shell (11) at the space between the divided portions (15a, 15b) of said heat transfer portion (15).

Drawing