JP5656411B2 - Rotary kiln - Google Patents

Description

  The present invention relates to a rotary kiln that conveys an object to be processed in the axial direction while swinging in a circumferential direction.

  Patent Document 1 discloses a rotary kiln that includes an inner cylinder, an outer cylinder, and an amorphous heat insulating material. The inner cylinder is made of ceramics. The outer cylinder is made of metal. The inner cylinder and the outer cylinder are arranged coaxially. The amorphous heat insulating material is filled in a gap between the inner cylinder and the outer cylinder. The object to be processed moves in the axial direction inside the inner cylinder.

  Each of the inner cylinder and the outer cylinder includes a heating section and a non-heating section. The heating section is accommodated in the heating unit. The non-heating section is not accommodated in the heating unit. The workpiece inside the inner cylinder is heated while moving by the heat from the heating section moving through the heating section of the outer cylinder, the irregular heat insulating material, and the heating section of the inner cylinder.

JP-A-6-3054 Japanese Patent Laid-Open No. 3-79984

  However, the ceramic inner cylinder has lower thermal conductivity than the metal inner cylinder. For this reason, in the vicinity of the boundary between the high-temperature heating section and the low-temperature non-heating section, the temperature gradient (the rate of temperature change per unit length in the axial direction) tends to increase. Therefore, a large thermal stress is likely to be generated near the boundary between the heating section and the non-heating section due to the temperature gradient. In addition, ceramic inner cylinders generally have lower toughness than metal inner cylinders. Therefore, there is a possibility that a problem occurs in the inner cylinder.

  In this regard, according to the rotary kiln of Patent Document 1, as described in [0020] of the same document, the inner cylinder is supported by the outer cylinder. For this reason, even if some cracks occur in the inner cylinder due to the temperature gradient, it is difficult for defects to occur.

  Patent Document 2 discloses a rotary kiln having an inner cylinder, an outer cylinder, and a gap. The inner cylinder and the outer cylinder are made of ceramics. The inner cylinder and the outer cylinder are arranged coaxially. An inert gas is sealed in a gap between the inner cylinder and the outer cylinder.

  Each of the inner cylinder and the outer cylinder includes a heating section and a non-heating section. The heating section is accommodated in the heating unit. The non-heating section is not accommodated in the heating unit. The workpiece inside the inner cylinder is heated while moving by heat from the heating section moving through the heating section of the outer cylinder, the inert gas, and the heating section of the inner cylinder.

  However, according to the rotary kiln described in Patent Document 2, not only the inner cylinder but also the outer cylinder are made of ceramics. For this reason, it is necessary to consider the temperature difference between the heating section and the non-heating section not only for the inner cylinder but also for the outer cylinder. In addition, the ceramic outer cylinder has lower thermal conductivity than the metal outer cylinder. For this reason, it is difficult for the heat of the heating unit to be transmitted to the workpiece.

  The rotary kiln of the present invention has been completed in view of the above problems. An object of the rotary kiln of the present invention is to provide a rotary kiln in which the heat of the heating part is easily transmitted to the workpiece, and the temperature gradient near the boundary between the heating section and the non-heating section of the inner cylinder is not easily increased.

(1) In order to solve the above problems, a rotary kiln according to the present invention includes a heating device having a heating unit, an outer heating section that is disposed substantially horizontally so as to be rotatable about an axis, and is accommodated in the heating unit, and the heating An outer non-heated section that is not accommodated in the section, and a metal outer cylinder that is coaxially disposed on the radially inner side of the outer cylinder so as to be rotatable around the axis in synchronization with the outer cylinder. An inner heating section accommodated in the inner heating section and an inner non-heating section not accommodated in the heating section, an inner tube made of ceramic in which an object to be processed moves in the axial direction, the outer heating section and the inner side A heating gap interposed between the heating section and a non-heating gap that is interposed between the outer non-heating section and the inner non-heating section and communicates with the heating gap. Moving from the heating gap to the non-heating gap, the inner non-heating section is heated. More, it characterized in that the temperature gradient in the vicinity of the boundary between the inner heating section and the inner non-heating section can be inhibited from increase.

  The rotary kiln of the present invention includes a heating device, an outer cylinder, an inner cylinder, a heating gap, and a non-heating gap. The outer cylinder includes an outer heating section and an outer non-heating section. The inner cylinder includes an inner heating section and an inner non-heating section.

  Between the heating section and the inner heating section, that is, the workpiece, from the radially outer side to the radially inner side, the heating section → the outer heating section of the outer cylinder → the heating gap → the inner heating section of the inner cylinder (Hereinafter referred to as “first heat transfer path” as appropriate) is secured. The object to be processed inside the inner heating section is heated while moving by the heat passing through the first heat transfer path. Here, the metal outer cylinder has higher thermal conductivity than the ceramic outer cylinder. For this reason, the heat of a heating part is easy to be transmitted to a to-be-processed object. In addition, since the thermal conductivity is high, the temperature gradient (the rate of temperature change per unit length in the axial direction) hardly increases near the boundary between the outer heating section and the outer non-heating section. Therefore, a large thermal stress is unlikely to occur near the boundary between the outer heating section and the outer non-heating section due to the temperature gradient. In addition, metal outer cylinders generally have higher toughness than ceramic outer cylinders. Therefore, it is difficult for trouble to occur in the outer cylinder.

  A heating gap and a non-heating gap are secured between the outer cylinder and the inner cylinder. As described above, the heating gap constitutes a part of the first heat transfer path. For this reason, the heating gap is heated by the heat from the heating unit. The non-heating gap communicates with the heating gap. For this reason, the heat of the heating gap moves to the non-heating gap. The unheated gap is heated by the transferred heat. An inner non-heating section of the inner cylinder is arranged inside the non-heating gap in the radial direction. For this reason, the inner non-heating section is heated by the heat of the non-heating gap. In this way, between the heating unit and the inner non-heating section, the heat transfer path of the heating unit → the outer heating section of the outer cylinder → the heating gap → the non-heating gap → the inner non-heating section of the inner cylinder (hereinafter referred to as “ Called "second heat transfer path"). The inner unheated section is heated by the heat passing through the second heat transfer path.

  According to the rotary kiln of the present invention, not only the inner heating section can be heated by the first heat transfer path, but also the inner non-heating section can be heated by the second heat transfer path. For this reason, it can suppress that the temperature gradient of the boundary vicinity of an inner side heating area and an inner side non-heating area becomes large.

(2) In the configuration of the above (1), said heating gap and the radial width of the non-heating gaps is not good is better to adopt a configuration is 1mm or more. The reason why the radial width of the heating gap and the non-heating gap is set to 1 mm or more is that, when the width is less than 1 mm, heat hardly moves from the heating gap to the non-heating gap. In particular, the fluid serving as the heat medium is less likely to flow from the heating gap to the non-heating gap.

(3) Preferably, in the configuration of (1) or (2), further, a difference in axial thermal expansion between the inner cylinder and the outer cylinder is allowed, and the non-heating gap is sealed from the outside. it is not good to be configured to have a gap sealing portion to be.

  The metal outer cylinder has a larger linear expansion coefficient than the ceramic inner cylinder. For this reason, the outer cylinder is more likely to thermally expand than the inner cylinder. Accordingly, the amount of axial deformation is greater in the outer cylinder than in the inner cylinder. If the difference in deformation is large, it is difficult to seal the non-heating gap from the outside. In this regard, according to the present configuration, the gap sealing portion is arranged. For this reason, the non-heating gap can be sealed from the outside while allowing a difference in the amount of axial deformation between the inner cylinder and the outer cylinder.

(4) Preferably, in the configuration of (1) to (3), the outer heating section, the mutual arrangement having a heat transfer hole communicating with the heating gap between the heating portion is not good .

  According to this configuration, the fluid serving as the heat medium flows from the heating unit to the heating gap via the heat transfer holes. For this reason, heat can be moved by heat transfer. Further, radiant heat is released from the surface of the heat source of the heating unit to the inner heating section through the heat transfer holes. For this reason, heat can be moved by thermal radiation. As described above, according to this configuration, the heat of the heating unit easily moves to the inner heating section (that is, the workpiece) and the inner non-heating section.

(5) In the configuration of the above (4), as 100% the area of the outer peripheral surface of the outer heating section, an opening area of the heat transfer Netsuana is not good is better to adopt a configuration is 10% or more. The reason why the opening area of the heat transfer holes is set to 10% or more is that when the heat transfer holes are less than 10%, the above-described heat transfer and heat transfer effects by heat radiation cannot be sufficiently obtained.

  According to the present invention, it is possible to provide a rotary kiln in which the heat of the heating part is easily transmitted to the workpiece, and the temperature gradient in the vicinity of the boundary between the heating section and the non-heating section of the inner cylinder is not easily increased.

It is a perspective view of the rotary kiln of one embodiment of the present invention. It is an axial sectional view of the rotary kiln. It is radial direction sectional drawing of the heating part vicinity of the rotary kiln. It is a perspective view of the front-end part of the rotary kiln. It is a disassembled perspective view of the connection part of the rotary kiln. It is a front view of the rotary kiln. It is a disassembled perspective view of the tire ahead of the rotary kiln. It is a perspective view of the rear-end part of the rotary kiln. It is an expanded sectional view in the frame IX of FIG. (A) is an enlarged view in the frame X of FIG. (B) is the schematic diagram of the distance-temperature relationship of the inner cylinder of the part shown to (a). It is a graph which shows a temperature measurement result.

  Hereinafter, embodiments of the rotary kiln of the present invention will be described.

<Composition of rotary kiln>
First, the structure of the rotary kiln of this embodiment is demonstrated. In FIG. 1, the perspective view of the rotary kiln of this embodiment is shown. FIG. 2 shows an axial sectional view of the rotary kiln. FIG. 3 shows a radial cross-sectional view in the vicinity of the heating part of the rotary kiln. In the drawings other than FIG. 9, for convenience of explanation, the gap between the outer cylinder 3 and the inner cylinder 4 is highlighted.

  As shown in FIGS. 1 to 3, the rotary kiln 1 of the present embodiment includes a heating device 2, an outer cylinder 3, an inner cylinder 4, a heating gap 50, a pair of non-heating gaps 51 f and 51 r, and a gap seal. The stop portion 6, the pair of tires 8 f and 8 r, the connecting portion 9, the pair of rollers 70 f, and the pair of rollers 70 r are provided.

[Rollers 70f, 70r]
The pair of rollers 70f are arranged on a gantry (not shown). The pair of rollers 70f are arranged side by side in the left-right direction. The roller 70f can rotate around the axis. Flange 700f is arrange | positioned at the front-back direction both ends of the roller 70f. The pair of rollers 70r is disposed behind the pair of rollers 70f with a predetermined interval therebetween. The pair of rollers 70r are arranged side by side in the left-right direction. The roller 70r can rotate around the axis.

[Inner cylinder 4]
The inner cylinder 4 is made of alumina and has a cylindrical shape extending in the front-rear direction. The inner cylinder 4 is disposed substantially horizontally (lowering gently from the front to the rear). The workpiece W is conveyed through the inner cylinder 4 from the front to the rear.

  The inner cylinder 4 includes an inner heating section 40 and a pair of front and rear inner non-heating sections 41f and 41r. The inner non-heating section 41 f is disposed in front of the inner heating section 40. The inner non-heating section 41r is disposed behind the inner heating section 40.

[Outer cylinder 3]
The outer cylinder 3 is made of stainless steel (SUS) and has a cylindrical shape extending in the front-rear direction. The outer cylinder 3 is disposed substantially horizontally (lowering gently from the front to the rear). The outer cylinder 3 is disposed on the radially outer side of the inner cylinder 4. The outer cylinder 3 is arranged coaxially with the inner cylinder 4. Both ends of the inner cylinder 4 in the front-rear direction protrude from the outer cylinder 3 in the front-rear direction.

  The outer cylinder 3 includes an outer heating section 30, a pair of front and rear outer non-heating sections 31f and 31r, a large number of heat transfer holes 32, a pair of front and rear flanges 33f and 33r, and a sprocket (not shown). Yes. The outer non-heating section 31 f is disposed in front of the outer heating section 30. The outer non-heating section 31 r is disposed behind the outer heating section 30. The large number of heat transfer holes 32 are arranged in the outer heating section 30 around the entire circumference. When the area of the outer peripheral surface of the outer heating section 30 is 100%, the total opening area of the numerous heat transfer holes 32 occupies 11%. The flange 33 f is disposed at the front end of the outer cylinder 3. Outer end mounting holes 330f (see FIG. 5 described later) are formed in the front surface of the flange 33f so as to be spaced apart from each other by 120 ° in the circumferential direction. The flange 33r is disposed at the rear end of the outer cylinder 3. The sprocket is disposed in front of the flange 33r. The sprocket is provided around the outer peripheral surface of the outer cylinder 3. A driving force in the rotational direction around the axis is transmitted from the motor (not shown) to the outer cylinder 3 via the sprocket.

[Heating device 2]
The heating device 2 includes a heating chamber 20, numerous heaters 21 u and 21 d, an outer wall 22, and a heat insulating wall 23. The heating chamber 20 is included in the heating unit of the present invention. The heating chamber 20 accommodates an outer heating section 30 of the outer cylinder 3 and an inner heating section 40 of the inner cylinder 4. The outer wall 22 is made of SUS and has a rectangular parallelepiped box shape. The heat insulation wall 23 is formed by combining a large number of refractory bricks. The heat insulating wall 23 is fixed to the inner surface of the outer wall 22. The heating chamber 20 is partitioned inside the heat insulating wall 23. A large number of heaters 21 u are arranged above the outer cylinder 3 in the heating chamber 20. A number of heaters 21u are arranged in the front-rear direction. A large number of heaters 21 d are arranged below the outer cylinder 3 in the heating chamber 20. A large number of heaters 21d are arranged in the front-rear direction.

[Connecting part 9]
In FIG. 4, the perspective view of the front-end part of the rotary kiln of this embodiment is shown. In FIG. 5, the disassembled perspective view of the connection part of the rotary kiln is shown. FIG. 6 shows a front view of the rotary kiln. In FIG. 5, the inner cylinder 4 is shown in a transparent manner. In FIG. 6, the inner cylinder 4 is hatched. As shown in FIGS. 4 to 6, the connecting portion 9 connects the outer peripheral surface of the inner cylinder 4 and the flange 33 f of the outer cylinder 3.

  The connecting portion 9 includes three holders 90, three connecting members 91, three link arms 92, and six link pins 93. The holder 90 is made of steel and has a partial arc shape extending in the circumferential direction over approximately 120 °. The three holders 90 are connected in an annular shape via three connecting members 91 described later. The three holders 90 cover the outer peripheral surface of the inner cylinder 4 by approximately 120 ° in the circumferential direction. The three holders 90 are disposed in front of the flange 33f. As shown by a thin line in FIG. 6, the curvature of the inner peripheral surface of the holder 90 in the natural state before being attached to the inner cylinder 4 is set larger than the design curvature of the outer peripheral surface of the inner cylinder 4. For this reason, the holder 90 is attached to the outer peripheral surface of the inner cylinder 4 in an unfolded state (with a reduced curvature). The inner peripheral surface of the holder 90 is in line contact with the outer peripheral surface of the inner cylinder 4. In other words, the three holders 90 are in line contact with the inner cylinder 4 at three points separated by approximately 120 °. An inner end mounting portion 900 is disposed substantially at the center in the circumferential direction of the holder 90. The inner end mounting portion 900 has an inner end mounting hole 900a. Both ends in the circumferential direction of the holder 90 are bent outward in the radial direction. A connecting portion 901 is formed in each of the pair of bent portions.

  The link arm 92 is made of steel and has a thin plate shape. The link arm 92 connects the flange 33f and the holder 90 in the radial direction. A total of three link arms 92 are arranged. The link arm 92 includes an outer end hole 920 and an inner end hole 921. The outer end hole 920 is formed at the outer end of the link arm 92. The outer end hole 920 and the outer end attachment hole 330f of the flange 33f are arranged in the front-rear direction. The link pin 93 is inserted into the outer end hole 920 and the outer end attachment hole 330f. For this reason, the link arm 92 can swing around the link pin 93. The inner end hole 921 is formed at the inner end of the link arm 92. The inner end hole 921 and the inner end mounting hole 900a of the holder 90 are aligned in the front-rear direction. The link pin 93 is inserted into the inner end hole 921 and the inner end mounting hole 900a. For this reason, the holder 90 can swing around the link pin 93.

  The connecting member 91 connects the holders 90 adjacent in the circumferential direction. The connecting member 91 includes a bolt 910, a nut 911, and a coil spring 912. The bolt 910 passes through a pair of adjacent connecting portions 901 in the clockwise direction in FIG. The nut 911 is screwed to the through end of the bolt 910. The coil spring 912 is interposed between the nut 911 and the connecting portion 901. By tightening the bolt 910 and the nut 911, the coil spring 912 stores an urging force in the extending direction. That is, the urging force of the coil spring 912 acts in a direction in which a pair of connecting portions 901 adjacent in the circumferential direction are brought close to each other.

[Tire 8f, 8r]
FIG. 7 is an exploded perspective view of the tire in front of the rotary kiln of the present embodiment. Note that the outer cylinder 3 is shown in a transparent manner. As shown in FIG. 7, the tire 8f includes an inner ring 80f, three link arms 82f, an outer ring 83f, and six link pins 84f. The outer ring 83f is made of steel and has an arc shape. As shown in FIG. 4, the outer ring 83f is mounted on a pair of left and right rollers 70f so as to be able to roll. Further, the outer ring 83f is interposed between a pair of front and rear flanges 700f. Returning to FIG. 7, the outer ring 83 f is formed with outer end attachment holes 830 f that are spaced apart by 120 ° in the circumferential direction.

  The inner ring 80f is made of steel and has an arc shape. The inner ring 80f is disposed on the radially inner side of the outer ring 83f. The inner ring 80f covers the outer peripheral surface of the outer cylinder 3 all around. An inner end mounting portion 800f is disposed on the inner ring 80f so as to be separated from each other by 120 ° in the circumferential direction. An inner end attachment hole 800fa is formed in the inner end attachment portion 800f.

  The link arm 82f is made of steel and has a thin plate shape. The link arm 82f connects the inner ring 80f and the outer ring 83f in the radial direction. A total of three link arms 82f are arranged. The link arm 82f includes an outer end hole 820f and an inner end hole 821f. The outer end hole 820f is formed at the outer end of the link arm 82f. The outer end hole 820f and the outer end mounting hole 830f of the outer ring 83f are aligned in the front-rear direction. The link pin 84f is inserted into the outer end hole 820f and the outer end attachment hole 830f. Therefore, the link arm 82f can swing around the link pin 84f. The inner end hole 821f is formed at the inner end of the link arm 82f. The inner end hole 821f and the inner end mounting hole 800fa of the inner ring 80f are arranged in the front-rear direction. The link pin 84f is inserted into the inner end hole 821f and the inner end attachment hole 800fa.

  The configuration of the tire 8r is the same as the configuration of the tire 8f. The arrangement of the tire 8r is symmetrical with the arrangement of the tire 8f. Therefore, explanation is omitted here.

[Gap sealing part 6]
In FIG. 8, the perspective view of the rear-end part of the rotary kiln of this embodiment is shown. FIG. 9 shows an enlarged cross-sectional view in the frame IX of FIG. As shown in FIGS. 8 and 9, the gap sealing portion 6 includes a stepped flange 60 and a seal ring 61. The stepped flange 60 is made of steel and includes a base portion 600 and a protruding portion 601. The base 600 has an annular shape. The base 600 is fixed to the flange 33r of the outer cylinder 3 with bolts and nuts. The protruding portion 601 has an annular shape. The protruding portion 601 is formed to protrude rearward from the inner peripheral surface of the base portion 600.

  The seal ring 61 is a heat-resistant gland packing and has an annular shape. The seal ring 61 is interposed between the rear surface of the flange 33r and the front surface of the protruding portion 601. The seal ring 61 is in elastic contact with the outer peripheral surface of the inner cylinder 4. For this reason, the non-heating gap 51r is isolated from the outside. Further, the outer peripheral surface of the inner cylinder 4 can slide relative to the seal ring 61 in the front-rear direction. For this reason, the inner cylinder 4 can be displaced relative to the outer cylinder 3 in the front-rear direction.

  Thus, the inner cylinder 4 and the outer cylinder 3 can be displaced in the axial direction (front-rear direction) by the connecting portion 9 at the front end portion and the gap sealing portion 6 at the rear end portion, and synchronously around the axis. It is connected so that it can rotate.

[Heating gap 50, non-heating gaps 51f, 51r]
As shown in FIG. 2, the heating gap 50 is interposed between the inner heating section 40 of the inner cylinder 4 and the outer heating section 30 of the outer cylinder 3. The non-heating gap 51 f is interposed between the inner non-heating section 41 f of the inner cylinder 4 and the outer non-heating section 31 f of the outer cylinder 3. The non-heating gap 51r is interposed between the inner non-heating section 41r of the inner cylinder 4 and the outer non-heating section 31r of the outer cylinder 3. The non-heating gap 51f, the heating gap 50, and the non-heating gap 51r communicate with each other in the front-rear direction. The radial widths of the heating gap 50 and the non-heating gaps 51f and 51r are both 2.5 mm.

<Rotary kiln movement>
Next, the movement of the rotary kiln 1 of this embodiment will be described. As described above, the driving force in the rotational direction is transmitted to the outer cylinder 3 from the motor via the sprocket. The driving force is transmitted to the inner cylinder 4 through the connecting portion 9 and the gap sealing portion 6 as shown in FIG. For this reason, the outer cylinder 3 and the inner cylinder 4 rotate around the axis in synchronism with the pair of rollers 70f and the pair of rollers 70r.

  The workpiece W moves from the front to the rear while swinging in the radial direction inside the inner cylinder 4 (because the inner cylinder 4 is rotating). The inner heating section 40 of the inner cylinder 4 is accommodated in the heating chamber 20. For this reason, the workpiece W is heated by the heaters 21u and 21d when passing through the inner heating section 40. Specifically, as shown in FIG. 3, the air in the heating chamber 20 heated by the heaters 21 u and 21 d flows into the heating gap 50 through the heat transfer holes 32. Further, radiant heat is released directly from the surfaces of the heaters 21 u and 21 d to the inner heating section 40 through the heat transfer holes 32. The workpiece W inside the inner cylinder 4 is heated by such heat transfer.

  FIG. 10A shows an enlarged view in the frame X of FIG. FIG. 10B shows a schematic diagram of the distance-temperature relationship of the inner cylinder in the portion shown in FIG. In FIG. 10B, the temperature gradient is shown by a straight line for convenience of explanation.

  As shown in FIGS. 10A and 10B, there is a temperature gradient near the boundary between the inner heating section 40 and the inner non-heating section 41 r of the inner cylinder 4. That is, as the distance from the heating chamber 20 increases, the temperature of the inner cylinder 4 gradually decreases.

  If the heating gap 50 and the non-heating gap 51r are separated, or if the heating gap 50 and the non-heating gap 51r themselves do not exist, the boundary between the inner heating section 40 and the inner non-heating section 41r of the inner cylinder 4 The temperature gradient in the vicinity increases as shown by a straight line L2. On the other hand, when the heating gap 50 and the non-heating gap 51r communicate with each other, air can flow from the heating gap 50 to the non-heating gap 51r as indicated by an arrow in FIG. . For this reason, the temperature gradient in the vicinity of the boundary between the inner heating section 40 and the inner non-heating section 41r of the inner cylinder 4 becomes smaller as a straight line L1.

<Effect>
Next, the effect of the rotary kiln 1 of this embodiment is demonstrated. As shown in FIG. 3, between the heating chamber 20 and the inner heating section 40, that is, the workpiece W, from the radially outer side to the radially inner side, the heating chamber 20 → the outer heating section 30 → the heating gap 50 → A first heat transfer path called the inner heating section 40 is secured. The workpiece W is heated while moving due to the heat passing through the first heat transfer path. Here, the metal outer cylinder 3 has higher thermal conductivity than the ceramic outer cylinder. For this reason, the heat of the heating chamber 20 is easily transmitted to the workpiece W. Further, since the thermal conductivity is high, as shown in FIG. 2, the temperature gradient is unlikely to increase near the boundary between the outer heating section 30 and the outer non-heating sections 31f and 31r. Therefore, a large thermal stress is unlikely to occur near the boundary between the outer heating section 30 and the outer non-heating sections 31f and 31r due to the temperature gradient. In addition, the metal outer cylinder 3 generally has higher toughness than the ceramic outer cylinder. Therefore, troubles are unlikely to occur in the outer cylinder 3.

  A heating gap 50 and non-heating gaps 51f and 51r are secured between the outer cylinder 3 and the inner cylinder 4. As described above, the heating gap 50 constitutes a part of the first heat transfer path. For this reason, the heating gap 50 is heated by the heat from the heating chamber 20. The non-heating gaps 51f and 51r communicate with the heating gap 50. For this reason, the heat of the heating gap 50 moves to the non-heating gaps 51f and 51r. The unheated gaps 51f and 51r are heated by the moved heat. Inner non-heating sections 41f and 41r of the inner cylinder 4 are arranged inside the non-heating gaps 51f and 51r in the radial direction. For this reason, the inner non-heating sections 41f and 41r are heated by the heat of the non-heating gaps 51f and 51r. Thus, between the heating chamber 20 and the inner non-heating sections 41f and 41r, the heating chamber 20 → the outer heating section 30 of the outer cylinder 3 → the heating gap 50 → the non-heating gaps 51f and 51r → the inner side of the inner cylinder 4 A second heat transfer path of non-heating sections 41f and 41r is secured. The inner non-heating sections 41f and 41r are heated by the heat passing through the second heat transfer path.

  According to the rotary kiln 1 of the present embodiment, not only the inner heating section 40 can be heated by the first heat transfer path, but also the inner non-heating sections 41f and 41r can be heated by the second heat transfer path. For this reason, as shown in FIG.10 (b), the temperature gradient of the boundary vicinity of the inner side heating area 40 and inner side non-heating area 41f, 41r can be made small.

  Further, as shown in FIG. 2, the radial widths of the heating gap 50 and the non-heating gaps 51f and 51r are both 2.5 mm. That is, it is 1 mm or more. For this reason, the air serving as the heat medium easily flows from the heating gap 50 to the non-heating gaps 51f and 51r.

  As shown in FIG. 9, a gap sealing portion 6 is disposed at the rear end portions of the inner cylinder 4 and the outer cylinder 3. For this reason, even though the inner cylinder 4 is made of alumina and the outer cylinder 3 is made of SUS, a difference in the amount of axial deformation due to the difference in linear expansion coefficient between both members can be allowed. In addition, the non-heating gap 51r can be sealed from the outside. Further, due to the elastic contact force of the seal ring 61, a difference in radial deformation amount due to a difference in linear expansion coefficient between the two members can be allowed. That is, even if the radial width of the non-heating gap 51r changes, the non-heating gap 51r can be sealed from the outside.

  As shown in FIG. 3, the outer cylinder 3 is provided with a large number of heat transfer holes 32. For this reason, air flows from the heating chamber 20 to the heating gap 50 through the heat transfer holes 32. Therefore, heat can be transferred by heat transfer. Further, radiant heat is released from the surfaces of the heaters 21 u and 21 d to the inner heating section 40 through the heat transfer holes 32. For this reason, heat can be moved by thermal radiation. As described above, according to the rotary kiln 1 of the present embodiment, the heat of the heating chamber 20 easily moves to the inner heating section 40 (that is, the workpiece W) and the inner non-heating sections 41f and 41r shown in FIG. Moreover, since air flows through many heat-transfer holes 32, it can suppress that the temperature of the inner side heating area 40 varies. For this reason, it becomes easy to heat the workpiece W uniformly.

  Moreover, when the area of the outer peripheral surface of the outer heating section 30 is 100%, the total opening area of the numerous heat transfer holes 32 occupies 11%. Since the total opening area is 10% or more, the heat transfer effect by the heat transfer and heat radiation can be sufficiently obtained.

  As shown in FIG. 6, a connecting portion 9 is disposed at the front end portions of the inner cylinder 4 and the outer cylinder 3. For this reason, although the inner cylinder 4 is made of alumina and the outer cylinder 3 is made of SUS, a difference in the amount of radial deformation due to the difference in linear expansion coefficient between both members can be allowed. That is, even if the radial width of the non-heating gap 51f changes, the inner cylinder 4 and the outer cylinder 3 can be continuously connected.

  Further, as shown in FIG. 2, a flange 700f is disposed on the roller 70f, while a flange is not disposed on the roller 70r. For this reason, the axial deformation of the outer cylinder 3 due to thermal expansion can be allowed. Further, as shown in FIG. 7, a gap is defined between the inner ring 80f and the outer ring 83f of the tire 8f. For this reason, the radial deformation of the inner ring 80f and the outer cylinder 3 due to thermal expansion can be allowed.

<Others>
The embodiment of the rotary kiln of the present invention has been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  The shape, arrangement, number, and opening area of the heat transfer holes 32 are not particularly limited. What is necessary is just to set suitably according to arrangement | positioning of the heaters 21u and 21d, the kind of to-be-processed object W, etc. The heat medium flowing through the heating gap 50 and the non-heating gaps 51f and 51r is not particularly limited. The heat medium may be an inert gas. The heat medium may be a liquid as well as a gas. The driving force transmission mechanism to the outer cylinder 3 and the inner cylinder 4 is not particularly limited. The outer cylinder 3 and the inner cylinder 4 may be rotated by driving the rollers 70f and 70r. The heat source of the heating chamber 20 is not particularly limited. A burner or the like may be used. The material of the inner cylinder 4 is not particularly limited. It may be made of other ceramics such as mullite and zirconia. The material of the outer cylinder 3 is not particularly limited. It may be made of other metals such as general structural rolled steel (SS) and carbon steel for mechanical structure (SC).

  Hereinafter, a temperature measurement experiment in which the temperature distribution in the axial direction (front-rear direction) of the inner peripheral surface of the inner cylinder 4 is measured will be described. An example is the rotary kiln 1 of the said embodiment. As shown in FIG. 2, the total length of the inner cylinder 4 in the front-rear direction is 2000 mm, the outer diameter (diameter) is 160 mm, and the inner diameter (diameter) is 148 mm. The overall length of the outer cylinder 3 in the front-rear direction is 1564 mm, the outer diameter (diameter) is 178 mm, and the inner diameter (diameter) is 165 mm. The radial widths of the heating gap 50 and the non-heating gaps 51f and 51r are both 2.5 mm. When the area of the outer peripheral surface of the outer heating section 30 is 100%, the total opening area of the large number of heat transfer holes 32 is 11%. The total length in the front-rear direction of the heating chamber 20 (= the total length in the front-rear direction of the outer heating section 30 = the total length in the front-rear direction of the inner heating section 40) is 950 mm. A comparative example is a rotary kiln which does not have the outer cylinder 3 with respect to the rotary kiln 1 of the said embodiment (that is, the rotary kiln of the existing single pipe (corresponding to the inner cylinder 4)).

As shown in FIG. 2, the center part in the front-rear direction of the rear wall of the heating apparatus 2 on the inner peripheral surface of the inner cylinder 4 is a point B, and the part in the 200 mm heating chamber 20 forward from the point B is the point A A point where the 125 mm tire 8r is arranged backward is defined as a point C. These points A to C were taken as temperature measurement positions. The temperature measurement results are shown in Table 1 and FIG.

  As shown in Table 1 and FIG. 11, it was found that in both the example and the comparative example, the temperature decreases as the distance from the heating chamber 20 increases. The temperature gradient between the points A and B is 0.75 (° C./mm) in the example (= (840−690) / 200) and 1.4 (° C./mm) in the comparative example (= (860−580). ) / 200). The temperature gradient between the points B to C is 2.08 (° C./mm) in the example (= (690-430) / 125) and 2.16 (° C./mm) in the comparative example (= (580-310). ) / 125). The temperature gradient between points A to C is 1.26 (° C./mm) in the example (= (840-430) / 325) and 1.69 (° C./mm) in the comparative example (= (860-310). ) / 325). That is, it was found that the temperature gradient in the example was smaller than that in the comparative example.

1: Rotary kiln, 2: Heating device, 3: Outer cylinder, 4: Inner cylinder, 6: Gap sealing part, 8f: Tire, 8r: Tire, 9: Connection part.
20: heating chamber (heating unit), 21d: heater, 21u: heater, 22: outer wall, 23: heat insulation wall, 30: outer heating section, 31f: outer non-heating section, 31r: outer non-heating section, 32: heat transfer Hole, 33f: Flange, 33r: Flange, 40: Inner heating section, 41f: Inner non-heating section, 41r: Inner non-heating section, 50: Heating gap, 51f: Non-heating gap, 51r: Non-heating gap, 60: Step Attached flange, 61: seal ring, 70f: roller, 70r: roller, 80f: inner ring, 82f: link arm, 83f: outer ring, 84f: link pin, 90: retainer, 91: connecting member, 92: link arm, 93 : Link pin.
330f: outer end mounting hole, 600: base, 601: protrusion, 700f: flange, 800f: inner end mounting portion, 800fa: inner end mounting hole, 820f: outer end hole, 821f: inner end hole, 830f: outer end Mounting hole, 900: inner end mounting portion, 900a: inner end mounting hole, 901: connecting portion, 910: bolt, 911: nut, 912: coil spring, 920: outer end hole, 921: inner end hole.
W: Object to be processed.

Claims (3)

A heating device having a heating section;
A metal outer cylinder that is disposed substantially horizontally so as to be rotatable about an axis and is housed in the heating section, and an outer non-heating section that is not housed in the heating section;
An inner heating section that is coaxially disposed radially inward of the outer cylinder and is accommodated in the heating section, and an inner non-heating section that is not accommodated in the heating section, so as to be rotatable around an axis in synchronization with the outer cylinder And a ceramic inner cylinder in which the workpiece is moved in the axial direction.
A heating gap interposed between the outer heating section and the inner heating section;
A non-heating gap that is interposed between the outer non-heating section and the inner non-heating section and communicates with the heating gap;
With
Between the heating section and the inner non-heating section of the inner cylinder, the heating section, the outer heating section of the outer cylinder, the heating gap, the non-heating gap, and the inner non-heating section of the inner cylinder A heat transfer path through the section is secured,
The heat of the heating part moves to the non-heating gap through the heat transfer path, and the inner non-heating section of the inner cylinder is heated, whereby the inner heating section and the inner non-heating section of the inner cylinder are heated. While suppressing the temperature gradient near the boundary with the section from increasing,
The heating gap and the radial width of the non-heating gaps is state, and are more 1 mm,
The non-heating gap is arranged on both sides in the axial direction of the heating gap,
The pair of non-heating gaps communicate with each other in the axial direction via the heating gap.
The outer heating section is a rotary kiln having a heat transfer hole communicating the heating unit and the heating gap .   The rotary kiln according to claim 1, further comprising a gap sealing portion that allows a difference in axial thermal expansion between the inner cylinder and the outer cylinder and seals the non-heating gap from the outside.   The rotary kiln according to claim 1 or 2, wherein the area of the outer peripheral surface of the outer heating section is 100%, and the opening area of the heat transfer holes is 10% or more.

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