JP6320321B2 - Heat insulation roller - Google Patents

Description

  The present invention relates to a heat insulating roller used in a high temperature furnace.

  Conventionally, a heat insulating roller used in a high temperature furnace such as a heat treatment furnace has been proposed in which cooling water is passed through the roller and the outer surface of the roller is cooled using heat conduction. For example, the heat insulating roller described in Patent Document 1 is configured by laminating a plurality of inorganic material disks in the axial direction on the outer periphery of a metal shaft formed to allow cooling water to pass therethrough. In this heat insulating roller, a fixed flange is welded to one end of a metal shaft, and a moving flange is movably provided at the other end. In addition, a heat-resistant metal tube is fitted between the two flanges, one end of the metal tube is fixed, and the other end is provided so as to be relatively movable with respect to the moving flange. It can be absorbed.

Japanese Patent No. 4101908

  By the way, in a heat insulating roll in which a plurality of disk-shaped members (hereinafter simply referred to as disks) are fitted to the outer periphery of a shaft through which cooling water is circulated and stacked in the axial direction, a combination of disks made of different materials is known. ing. For example, there is one in which variations in the surface temperature of the heat insulating roll are suppressed by combining two types of disks made of materials having different thermal conductivities. However, when disks of different materials are combined, the thermal conductivity is different, so the member temperature is different, and the linear expansion coefficient (thermal expansion coefficient) is also different. There is a difference in the amount of thermal expansion during use.

  Although the thermal expansion and contraction change in the axial direction is absorbed in the heat insulating roll of Patent Document 1 above, since the thermal expansion in the radial direction is not taken into consideration, the disk that has greatly expanded in the radial direction when the heat insulating roll is used. There is a possibility that a large frictional force is generated between the disk and the outer tube by the outer peripheral surface of the tube being in contact with the inner peripheral surface of the outer tube arranged on the outer side. When the frictional force between the disk and the outer tube increases as described above, the thermal strain is restrained and thermal stress is generated, which may damage the heat insulating roller.

  The present case has been devised in view of such a problem, and an object of the heat insulating roller used in the high temperature furnace is to suppress the generation of thermal stress. The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

(1) The heat insulating roller disclosed herein is a heat insulating roller used in a high-temperature furnace, and includes a cylindrical inner pipe through which a cooling medium flows. Further, the heat insulating roller is a plurality of first disks that are externally fitted to the inner pipe and arranged in the axial direction of the inner pipe, and are fitted to the inner pipe and arranged in the axial direction of the inner pipe, the amount of thermal expansion when used in the first circle the hot furnace than Release is rather large, a plurality of the second disc to be pressed in the axial direction together with the first disc, having the inner pipe coaxially, the A cylindrical outer tube covering the outer periphery of the first disk and the second disk. Moreover, the insulation roller, said the second disc outer peripheral surface of the disposed between the inner peripheral surface of the outer tube, the clearance between the outer peripheral surface and the inner circumferential surface definitive when the use is not a negative value Thus, an initial clearance set in advance is provided.

(2) It is preferable that the inner tube and the second disk each have a dimensional tolerance set to a minus side, and the outer tube has a dimensional tolerance set to a plus side.
(3) It is preferable that the first disk is formed of a heat insulating material and disposed so that a ratio of the first disk in the axial direction of the inner tube is larger than that of the second disk.
(4) The first disks are arranged at a predetermined number with an interval in the axial direction of the inner tube, and the second disks are arranged at a predetermined number between the adjacent first disks. It is preferable.

  According to the heat insulating roller of the disclosure, it is possible to suppress the frictional force between the second disk and the outer tube that is generated during use in the high temperature furnace. That is, since it is possible to prevent the heat distortion of the heat insulating roller during use, the generation of thermal stress can be suppressed. Thereby, damage to the heat insulating roller can be avoided.

It is a typical axial direction sectional view showing the composition (state at the time of normal temperature) of the heat insulation roller concerning an embodiment. It is the A section enlarged view of FIG.

  With reference to drawings, the heat insulation roller as embodiment is demonstrated. The embodiment described below is merely an example, and there is no intention of excluding various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit of the present embodiment, and can be selected or combined as necessary.

[1. Constitution]
FIG. 1 is a schematic axial sectional view showing the configuration of the heat insulating roller 1 of the present embodiment, and shows a state at room temperature (for example, 20 ° C.). FIG. 2 is an enlarged view of part A of FIG. In FIG. 1, hatches representing the cross sections of disks 7 and 8 and nuts 6 to be described later are omitted, and in FIG. 2, all hatches are omitted. The heat insulating roller 1 is used, for example, when a high temperature object is conveyed in a high temperature furnace such as a heat treatment furnace. For this reason, the heat insulation roller 1 may become high temperature exceeding 1000 degreeC at the time of use.

  As shown in FIG. 1, the heat insulating roller 1 includes a cylindrical inner tube 2 in which a plurality of two kinds of disks 7 and 8 of different materials are fitted on each other in the direction of the central axis C (hereinafter referred to as the axial direction). The outer periphery of these discs 7 and 8 is covered with the outer tube 3 and arranged. The central axis C is the axis of the inner tube 2 and the axis of the heat insulating roller 1. The inner tube 2 is a component that constitutes the rotating shaft of the heat insulating roller 1. A cooling medium flows through the inner pipe 2 as indicated by black arrows in the figure. Thereby, the heat insulation roller 1 at the time of use is cooled.

  A first flange 4 fixed by welding is provided on one side (the left side in the figure) of the outer peripheral surface 2a of the inner tube 2. On the other hand, on the other side (right side in the figure) of the outer peripheral surface 2a of the inner tube 2, there are a second flange 5 that is movable in the axial direction, and a nut 6 that is screwed into a screw portion formed on the outer peripheral surface 2a. Provided. The nut 6 gives an urging force in the axial direction to the second flange 5. Between the first flange 4 and the second flange 5, a plurality of two types of disks 7 and 8 each having a circular hole at the center are arranged. These disks 7 and 8 are pressed in the axial direction by the first flange 4 and the second flange 5 when the second flange 5 is biased toward the first flange 4 by the nut 6. The plurality of disks 7 and 8 are each formed of the same material and the same shape.

  The outer tube 3 is coaxial with the inner tube 2, one end (left end in the figure) is fixed to the first flange 4 by welding, and the other end (right end in the figure) is relative to the second flange 5. It is provided so as to be movable. That is, one of the outer pipes 3 in the axial direction is provided as a fixed end, and the other is provided as a free end. Thereby, restraint of the thermal elongation of the outer tube 3 is prevented, and damage such as buckling, creep and ratchet deformation of the outer tube 3 is avoided.

In the present embodiment, one of the two types of disks 7 and 8 that has a small thermal expansion amount (thermal expansion amount) at the time of use is called a first disk 7 and the other one that has a large thermal expansion amount at the time of use is a second disk. Call it 8. Since the thermal expansion amount in use and the linear expansion coefficient (thermal expansion coefficient) are in a proportional relationship, the linear expansion coefficient α ₂ of the second disk 8 is more than the linear expansion coefficient α ₁ of the first disk 7. Can also be said to be large (α ₁ <α ₂ ). The first disk 7 is formed of a heat insulating material made of inorganic fibers such as glass fibers and ceramic fibers. On the other hand, the second disk 8 is formed of a metal such as stainless steel or high Cr steel. The first disk 7 and the second disk 8 also have different thermal conductivities. The second disk 8 of the present embodiment has a higher thermal conductivity than the first disk 7.

  As shown in FIG. 2, the first disk 7 has an outer peripheral surface 7 a that contacts the inner peripheral surface 3 b of the outer tube 3 and the inner peripheral surface 7 b that is the outer peripheral surface of the inner tube 2 when the heat insulating roller 1 is at room temperature. It has an inner diameter and an outer diameter so as to contact 2a. On the other hand, the second disk 8 forms a predetermined clearance 9 between the outer peripheral surface 8a and the inner peripheral surface 3b of the outer tube 3 when the heat insulating roller 1 is at normal temperature, and the inner peripheral surface 8b is the inner tube 2. The inner diameter and the outer diameter are in contact with the outer peripheral surface 2a.

That is, a clearance 9 is provided in advance on the inner side of the outer tube 2 on the outer periphery of the second disk 8 having a large amount of thermal expansion during use (having a large linear expansion coefficient α ₂ ), and the outer peripheral surface 8 a of the second disk 8. And the inner peripheral surface 3b of the outer tube 2 are brought into a non-contact state. Hereinafter, this clearance 9 is referred to as initial clearance 9. The initial clearance 9 is set in advance so that the contact between the outer peripheral surface 8a of the second disk 8 and the inner peripheral surface 3b of the outer tube 2 starts when the heat insulating roller 1 is used (that is, at a high temperature).

  The initial clearance 9 takes into account the respective thermal expansion amounts in the radial direction of the inner tube 2, the outer tube 3 and the second disk 8 when the heat insulating roller 1 is used. X)) is calculated. In other words, the heat insulating roller 1 has each dimension in the radial direction of the inner tube 2, the outer tube 3, and the second disk 8 so that an initial clearance 9 having a length X calculated based on each thermal expansion amount is formed. Is set. In addition, the dimension of the radial direction of the 1st disk 7 is also set by each dimension of the radial direction of the inner tube 2 and the outer tube 3 being set.

Here, an example of a method for calculating the length X of the initial clearance 9 will be described. Hereinafter, the length from the central axis C to the radial center 8c of the thickness of the second disk 8 (the length obtained by subtracting the inner diameter from the outer diameter divided by 2) at the normal temperature of the heat insulating roller 1 is This is called the center radius r _{2 of} the two disk 8. Similarly, a length of up radial center 2c of the wall thickness of the inner tube 2 from the center axis C, called the central radius r ₃ of the inner tube 2, the radial center 3c of the wall thickness of the outer tube 3 from the central axis C This length is referred to as the center radius r _{4 of} the outer tube 3. In addition, the linear expansion coefficients of the inner tube 2 and the outer tube 3 are α ₃ and α ₄ , respectively.

First, the in-furnace temperature of the high-temperature furnace in which the heat insulating roller 1 is used, the cooling conditions of the heat insulating roller 1 (cooling medium temperature, flow rate, cooling time, etc.), the heat transfer coefficient of the inner pipe 2 which is a cooling pipe, The heat conduction calculation is carried out from the dimensions and the respective thermal conductivities of the disk 8, the inner tube 2 and the outer tube 3, and each of the second disk 8, the inner tube 2 and the outer tube 3 when the heat insulating roller 1 is used. calculating an average temperature _{T 2, T 3, T 4} .

Next, the temperature at normal temperature is subtracted from each of the above temperatures T ₂ , T ₃ , T ₄ , and the temperature differences ΔT ₂ , ΔT ₃ , ΔT ₄ of the second disk 8, the inner tube 2, and the outer tube 3 are obtained. Ask. The temperature differences ΔT ₂ , ΔT ₃ , ΔT ₄ are multiplied by the linear expansion coefficients α ₂ , α ₃ , α ₄ and the center radii r ₂ , r ₃ , r ₄ , respectively. The respective thermal expansion amounts Δr ₂ , Δr ₃ , Δr ₄ in the radial direction of the disk 8, the inner tube 2, and the outer tube 3 are calculated.

Here, when the length of the clearance 9 'between the outer peripheral surface 8a of the second disk 8 and the inner peripheral surface 3b of the outer tube 3 when the heat insulating roll 1 is used (hereinafter referred to as the clearance 9' during use) is X '. The length X ′ of the in-use clearance 9 ′ is expressed by the following formula (1).
X ′ = X + Δr ₄ −Δr ₂ −Δr ₃ (1)

As described above, the initial clearance 9 is set so that the contact between the outer peripheral surface 8a of the second disk 8 and the inner peripheral surface 3b of the outer tube 2 starts when the heat insulating roller 1 is used (X '= 0). ) Is set. That is, the length X of the initial clearance 9 is calculated by the following equation (2).
X = Δr ₂ + Δr ₃ −Δr ₄
= Α ₂ ΔT ₂ r ₂ + α ₃ ΔT ₃ r ₃ −α ₄ ΔT ₄ r ₄ (2)

  The respective dimensions in the radial direction of the inner tube 2, the outer tube 3 and the second disk 8 are set so that the initial clearance 9 having this length X is formed. However, in the heat insulating roller 1 of the present embodiment, the initial clearance 9 is set so that the length X ′ of the clearance 9 ′ during use does not become a negative value. That is, the dimensional tolerance of the outer tube 3 is set on the plus side, and the dimensional tolerances of the inner tube 2 and the second disk 8 are both set on the minus side. Thereby, at the time of use of the heat insulation roller 1, at least the second disk 8 and the outer tube 3 are prevented from being an interference fit.

  In addition, each axial direction length of the 1st disk 7 and the 2nd disk 8 is not specifically limited, These may be the same length and a different length may be sufficient as them. Further, the first disks 7 are arranged at a predetermined number with a predetermined interval in the axial direction of the inner tube 2, and the second disks 8 are arranged at predetermined intervals between the adjacent first disks 7, 7. Be placed. These predetermined numbers are not particularly limited, and may be the same number or different numbers.

  However, the heat insulating roller 1 of the present embodiment, as shown in FIGS. 1 and 2, the proportion of the inner tube 2 in the axial direction is such that the first disk 7 is larger than the second disk 8. Each axial length and each predetermined number are set. In other words, the first disk 7 is arranged so that the proportion of the first disk 7 in the axial direction is larger than that of the second disk 8. For example, when the axial lengths of the first disk 7 and the second disk 8 are the same, the predetermined number of the first disks 7 is set to be larger than the predetermined number of the second disks 8. Further, when the axial length of the first disk 7 is longer than the axial length of the second disk 8, the predetermined number of the first disk 7 and the predetermined number of the second disk 8 may be the same.

[2. effect]
Since the above-described heat insulating roller 1 has an initial clearance 9 set in advance so that contact between the outer peripheral surface 8a of the second disk 8 and the inner peripheral surface 3b of the outer tube 3 starts when used in a high-temperature furnace, The frictional force generated between the second disk 8 and the outer tube 3 during use in the high temperature furnace can be suppressed. That is, it is possible to prevent the thermal strain of the heat insulating roller 1 from being restricted during use, and thus it is possible to suppress the generation of thermal stress. Thereby, damage to the heat insulating roller 1 can be avoided.

  In the heat insulating roller 1 described above, since the dimensional tolerances of the inner tube 2 and the second disk 8 are both set to the minus side and the dimensional tolerance of the outer tube 3 is set to the plus side, the clearance 9 ′ during use is It will never be negative. For this reason, at the time of use of the heat insulation roller 1, generation | occurrence | production itself of the frictional force between the 2nd disk 8 and the outer tube | pipe 3 can be suppressed, and generation | occurrence | production of a thermal stress can further be suppressed. Even if there is a minute clearance 9 ′ during use, the cooling effect by the cooling medium passing through the inner tube 2 is transmitted to the outer tube 3 by heat conduction via the first disk 7, and the outer tube 3. The temperature is controlled to an appropriate temperature. Further, the load of the conveyed product can be borne by the first disk 7. Accordingly, the presence of a minute clearance 9 'during use does not cause a problem.

  The above-described heat insulating roller 1 is arranged such that the proportion of the first disk 7 in the axial direction is larger than that of the second disk 8. Therefore, the temperature of the outer tube 3 can be controlled to an appropriate temperature by heat conduction via the first disk 7. Further, the first disk 7 can bear a large load on the conveyed product. If arranged in this way, the temperature of the outer tube 3 can be controlled to a more appropriate temperature by heat conduction via the first disk 7 even when a minute clearance 9 ′ in use exists. In addition, the first disk 7 can bear a greater load on the conveyed product.

  Further, in the heat insulating roller 1 described above, the first disks 7 are arranged at a predetermined number with an axial interval, and the second disks 8 are arranged at a predetermined number between the adjacent first disks 7 and 7. Therefore, the temperature distribution in the axial direction of the heat insulating roller 1 can be made uniform, and variations in the surface temperature of the outer tube 3 can be suppressed. Thereby, it is possible to easily maintain the temperature of the outer surface of the heat insulating roller 1 (surface temperature of the outer tube 3) at an appropriate temperature.

[3. Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, the above-described method for calculating the length X of the initial clearance 9 is an example, and is not limited to the above. In the above-described method, the temperatures T ₂ , T ₃ , T ₄ of the second disk 8, the inner tube 2, and the outer tube 3 when the heat insulating roller 1 is used are calculated by conducting heat conduction. These temperatures may be acquired by actual measurement, or calculation and actual measurement may be combined.

  In the above embodiment, the dimensional tolerance of the outer tube 3 is set on the plus side so that the length X ′ of the clearance 9 ′ in use does not become a negative value, and the dimensional tolerance of the inner tube 2 and the second disk 8 is set. Are set on the negative side, but the dimensional tolerances are not limited to these. For example, the dimensional tolerances of the inner tube 2, the outer tube 3, and the second disk 8 are all set to the negative side, and the length X ′ of the clearance 9 ′ in use is allowed to be slightly positive. You may do it.

DESCRIPTION OF SYMBOLS 1 Heat insulation roller 2 Inner tube 3 Outer tube 7 First disk 7a Outer peripheral surface 7b Inner peripheral surface 7c Radial center 8 Second disc 8a Outer peripheral surface 8b Inner peripheral surface 8c Radial center 9 Initial clearance

Claims (4)

A heat insulating roller used in a high temperature furnace,
A cylindrical inner pipe through which a cooling medium flows;
A plurality of first disks externally fitted to the inner tube and disposed in the axial direction of the inner tube;
Are arranged in the axial direction of the inner tube is fitted on the inner tube, the amount of thermal expansion when used in the first circle the hot furnace than Release large active, is pressed in the axial direction together with the first disc A plurality of second disks,
A cylindrical outer tube that is coaxial with the inner tube and covers the outer circumference of the first disk and the second disk;
Wherein the second disc outer peripheral surface of the disposed between the inner peripheral surface of the outer tube, the initial clearance of the outer peripheral surface definitive during use and the inner peripheral surface is set in advance so as not to negative A heat insulating roller, comprising: a clearance; The inner pipe and the second disk are both set with a dimensional tolerance on the negative side,
The heat insulation roller according to claim 1, wherein the outer tube has a dimensional tolerance set to a plus side. 3. The heat insulating roller according to claim 1, wherein the first disk is disposed so that a ratio of the first disk in the axial direction of the inner tube is larger than that of the second disk. The first disks are arranged at predetermined intervals with an interval in the axial direction of the inner tube,
The heat insulation roller according to any one of claims 1 to 3, wherein the second disks are arranged at a predetermined number between the adjacent first disks.

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