JPH10237539A - Device for supporting radiant tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deformation and the cracking of a radiant tube caused by expansion and shrinkage in high temp. and to drastically improve the service life by arranging a rotary member between support arranged to a bending tube of the radiant tube in a heat treatment furnace and a receiving metallic tool projected from the furnace wall. SOLUTION: The rotary member is arranged between the support 3 arranged to the curving tube 2 of the radiant tube in the heat treatment furnace and the receiving metallic tool 4 projected from the inner wall of the furnace. The rotary member uses a roller 6 or a spherical body rotating by centering a shaft 2 fitted to the support 3, and also, on the surface of the receiving metallic tool 4, a recessed part matching with a part of the rotary body and introducing this rotary body, is arranged. Since the shifting of the support 3 at the time of deforming due to the expansion and the shrinkage of the radiant tube caused by change of the temp., is executed through the roller 6, the support 3 can smoothly and easily be shifted in the receiving metallic tool 4 and the development of bending and crack of the radiant tube caused by the restriction of shifting of the support 3 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supporting a radiant tube installed in a heat treatment furnace and used as a radiant heat source in the furnace.

[0002]

2. Description of the Related Art In a steel or other heat treatment furnace, when fuel cannot be burned in the furnace, a radiant tube made of a heat-resistant steel tube is installed in the furnace, and a high-temperature gas heated from outside the furnace by a burner or the like is used. Is supplied into the radiant tube to heat the inside of the furnace by radiant heat from the outer periphery of the radiant tube while keeping the furnace atmosphere constant.

[0003] Radiant tubes include a U-shaped or W-shaped tube in which a part of a tube is curved and a curved tube portion is provided in the middle thereof, a straight tube having only a straight tube, and a single-ended tube in which two straight tubes are arranged. There are shapes. For example, as shown in FIG. 1, a W-shaped radiant tube has two long and short straight tubes 1.
a, 1b, 1c, and 1d are arranged in parallel at a distance with a short one in between, and a curved tube 2a curved by 180 °
2b and 2c are welded and connected in a W shape.

[0004] The radiant tubes may be installed in a furnace in a vertical type, a horizontal type, a vertical suspension type, or the like. When the W-shaped radiant tube is installed vertically in the furnace as shown in FIG. 1, the open ends of the straight tubes 1a and 1b are aligned in the vertical direction and fixed to the furnace wall 5a.
a, 2b, 2c each support 3a, 3b, 3c welded
Are provided so as to protrude from the furnace walls 5a, 5b.
b, 4c. In addition, in the case of the U-shaped radiant tubes and when these radiant tubes are installed horizontally, the radiant tube is supported by the support and the receiving member as described above.

[0005] Since such a radiant tube is used at a high temperature in a heat treatment furnace, a large heat load is applied to the tube and the radiant tube is heated.
Since thermal stress due to cooling or temperature gradient, creep stress due to its own weight at high temperature, etc. act, deformation such as bending and cracks are likely to occur. In particular, cracks are likely to occur near the connection between the second straight pipe 1b and the first curved pipe 2a, and this has been a major cause of shortening the life of the radiant tube.

[0006]

As described above, the conventional radiant tube is subjected to a severe thermal load, so that deformation and cracks are generated. In particular, the conventional radiant tube is in contact with the first curved tube 2a of the second straight tube 1b shown in FIG. There is a disadvantage that cracks tend to occur near the connection point, and the life is short.

The present invention has been made in view of such a conventional situation,
An object of the present invention is to provide a radiant tube support device capable of suppressing deformation and cracking of a radiant tube and greatly improving the life thereof.

[0008]

In order to achieve the above object, a radiant tube supporting device provided by the present invention comprises:
A support provided at the end of the curved tube of the radiant tube,
A rotating member is interposed between a metal protruding from the furnace wall and supporting the support.

A conventional radiant tube support device is:
As described above, since the support provided on the curved tube of the radiant tube is supported by the metal fittings protruding from the furnace wall, adhesion (galling) occurs during use, and sliding between the support and the metal fittings occurs. Movement is smooth and not easy. For this reason, thermal expansion and thermal contraction of the radiant tube are restricted,
Due to the repetition of the expansion and contraction, deformation such as bending is likely to occur. In addition, it is considered that a crack is more likely to be induced by the progress of the deformation than the first curved pipe of the second straight pipe having a particularly large temperature gradient.

Therefore, in the present invention, a rotating member is interposed between the support provided at the end of the curved tube of the radiant tube and a metal protruding from the furnace wall, so that the support and the metal can be interposed between the support and the metal. The support device is configured to reduce the contact resistance and facilitate the mutual movement, thereby releasing the thermal expansion and thermal contraction without restraint. In the present invention, it is preferable that the receiving object is provided with a concave portion on which a part of the rotating member fits and guides the surface on which the rotating member rolls. Roller as a rotating member, especially one with a rotating shaft integrated with the roller body, or a sphere (ball)
Is suitable. In the case where a shaft that is a rotating shaft is integrated with the roller body, the support or the receiving object is opened larger than the size of the shaft, and the shaft is inserted before the roller is sandwiched between the support and the receiving object. A structure is provided in which an elongated hole for supporting is provided and the roller body is held. In addition, these rotating members can be made of the same heat-resistant steel as the radiant tube, or ceramics such as silicon carbide, and provided with a surface treatment layer that is subjected to thermal spraying or overlaying to improve heat resistance. You can also.

The radiant tube support device of the present invention will be specifically described with reference to the drawings. First, FIGS. 2 and 3
Is a device in which a roller 6 is provided as a rotating member between a support 3 provided on a curved tube 2 of a radiant tube and a receiving member 4 protruding from a furnace wall. A through hole is formed along the axis of the roller 6, and a shaft 7 inserted into the through hole is fitted into a semicircular groove 8 provided in the support 3. By placing the roller 6 on the upper surface of the receiving object 4, the radiant tube is supported on the furnace wall.

According to the supporting device having the structure shown in FIGS. 2 and 3, since the support 3 is moved via the roller 6 due to the thermal expansion and thermal contraction of the radiant at tube, the support 3 moves on the receiving object 4. The radiant tube can be moved smoothly and easily, and the bending or cracking of the radiant tube due to the restriction of the movement of the support 3 can be suppressed.

The supporting device shown in FIG. 4 and FIG.
A plurality of spheres 10 are arranged side by side as a rotating member on the upper surface of the receiver, and a stopper 11 having a height smaller than the diameter of the sphere 10 is provided on the outer peripheral edge of the receiver 4, so that the sphere 10 falls from the upper surface of the receiver 4. Is to be prevented. The support 3 of the radiant tube is placed in contact with the plurality of spheres 10, and the axial movement of the support 3 on the metal receiving member 4 due to thermal expansion or thermal contraction is smoothly and easily performed by the rotation of the sphere 10. .

Further, another supporting device shown in FIGS. 6 and 7 uses a cylindrical roller 12 as a rotating member. That is, the rail 13 is provided on the upper surface of the receiving object 4 along the axial center line.
An annular concave portion 14 is provided at the center in the longitudinal direction of the outer peripheral surface of the roller 12 so as to fit into the rail 13.
Are arranged on the upper surface of the receiving object 4 so that the annular concave portion 14 and the rail 13 are fitted. A stopper 11 having a height lower than the diameter of the roller 12 is provided at a tip of the metal receiver 4 on the side opposite to the furnace wall to prevent the roller 12 from dropping from the upper surface of the metal receiver 4. Radiant tube support 3 has multiple rollers 12
The support 3 is moved in the axial direction on the metal receiving member 4 by thermal expansion or thermal contraction through the rollers 12, so that it is smooth and easy.

As described above, according to the supporting device of the present invention in which the rotating member is interposed between the support and the receiving object, the contact resistance between the support and the receiving object is reduced, and the supporting member is relatively easily moved. Even if the radiant tube thermally expands or contracts, the support can easily move on the metal receiving member to release the expansion and contraction. Therefore, deformation and cracking of the radiant tube due to thermal stress can be effectively prevented, and the life thereof can be greatly extended.

Although the supporting apparatus using the rollers as shown in FIGS. 2 and 3 can sufficiently achieve the object intended in the present invention, since the temperature in the furnace is high, the supporting apparatus can be used for a long time. In the case of using the body of the rotating member (the inner peripheral surface of the roller 6)
And the rotating shaft (outer peripheral surface of the shaft 7) is liable to be baked at high temperatures to cause poor rotation of the rotating member or to deteriorate the rotating performance of the rotating member, thereby causing thermal expansion of the radiant tube. Also, there is a concern that the movement of the radiant tube may be deformed such as bending due to the generation of thermal stress due to the movement due to heat shrinkage.

In the present invention, when there is such a concern, a configuration as shown in FIGS. 8A to 8C is applied.
8A to 8C, the main body of the roller 6 and the shaft 6a are integrated and rotatably supported via a washer 9 in a long hole 3a provided in the support 3. . With such a structure, the roller 6 does not slip on the support 3 and the receiving object 4. Further, since the shaft portion 6a of the roller 6 is passed through the elongated hole 3a, the roller 6 is installed when the radiant tube is installed.
But it doesn't fall easily. In particular, when the radiant tube is extended, the roller 6
The roller 6 is provided with an inclined surface in order to appropriately roll the roller 6, so that the roller 6 can secure a movement allowance of the roller 6 at the initial position where the roller 6 is sandwiched between the support 3 and the metal receiving member 4. In the example of FIG. 8, the roller 6 comes to the tip of the support 3 so that the opening surface below the elongated hole 3a is inclined toward the tip so that the initial position can be set. It is preferable that the opening is larger than the size of the shaft 6a so that the opening 6a is in contact with the opening surface of the elongated hole 3a and burning does not occur at that position (when the roller 6 is placed at the initial position, the shaft 6a It does not touch any part of the long hole 3a). The length of the elongated hole 3a may be at least half the moving distance of the radiant tube. In the configuration shown in FIGS. 8A to 8C, the roller 6 is set at the distal end of the support 3, and when the support 3 moves toward the distal end due to thermal expansion of the radiant tube, The roller 6 rolls between the support 3 and the receiving object 4 and moves gradually to the mounting portion of the support. At this time, the shaft 6a smoothly expands and contracts without contacting the opening surface of the elongated hole 3a. . In particular, FIG.
As shown in (c), if a groove M is provided in the metal receiving member 4 so as to surround the surface on which the roller 6 rolls, the support 3 will fall off the metal receiving member 4 even if the radiant tube is deformed by thermal expansion or contraction. It is not.

FIGS. 9 (a) to 9 (c) show an example in which the body of the roller 6 is curved and the metal receiving member 4 having the groove M adapted to the bending is combined. It can also be applied to what is being done without modifying the receiving hardware.

FIGS. 10 (a) to 10 (c) show a single sphere 1 as a rotating member interposed between the support 3 and the receiving member 4. FIG.
This is an example in which 0 is applied. With such a structure, even when the thermal expansion and contraction deviate from the axial direction, the sphere can rotate smoothly and restrain the restraint.

FIGS. 11 (a) and 11 (b) show an apparatus using the sphere 10 and having the structure shown in FIG. 10 described above, in particular, a concave portion for guiding the sphere 10 to the bottom of the groove M of the metal receiving member 4. M ₁
Is provided. In such a structure, even if the radiant tube is deformed unevenly, the side surface of the support 3 does not come into contact with the side wall of the groove M, so that the support 3 and the receiver 4 move relative to each other. Therefore, there is an advantage that thermal expansion and contraction of the radiant ant tube can be reliably absorbed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the radiant tube support device of the present invention will be described with reference to FIGS. The radiant tube has a thickness of about 10 m as shown in FIG.
m between the first straight pipe 1a and the fourth straight pipe 1d having a length of about 2510 mm, and the second straight pipe 1 having a length of about 1495 mm.
b and the third straight pipe 1c are arranged in parallel at a distance from each other,
Curved pipes 2a, 2b and 2c each having a central radius of curvature of about 150 mm and curved by 180 ° are welded to these and connected in a W shape.

The thickness of the curved pipes 2a, 2b, 2c is slightly larger than the straight pipes 1a, 1b, 1c, 1d.
The inner diameter of each straight pipe 1a, 1b, 1c, 1d is about 17
The diameter is in the range of 5 to 195 mm, and is gradually reduced in this order so as to reach the fourth straight pipe 1d.

Supports 3a, 3b, 3c made of heat-resistant steel are welded to the ends of the curved pipes 2a, 2b, 2c, respectively. Each of the supports 3a, 3b, and 3c includes one roller 6 at the tip of the support 3, as shown in FIGS. That is, the inside of the lower end of the tip of the support 3 is hollow, and the roller 6 is housed in this hollow so that the lower half is exposed.

The roller 6 is made of heat-resistant steel drum having a maximum diameter of about 70 mm and having a large diameter at its central portion. A shaft 7 having a diameter of about 30 mm is inserted through a through hole formed along the axis of the roller. After inserting the washers 9 at both ends of the shaft 7, the length of the shaft 7 protruding from the curved tube 2 is about 245 mm and the width is about 100 m.
The shaft 7 is fitted and fixed in a semicircular groove 8 provided on the lower surface of the m support 3.

The radiant tube is placed in the heat treatment furnace by placing the roller 6 held by the support 3 on the upper surface of the metal receiving member 4 projecting from the furnace wall as shown in FIGS. Supported within. The supporting method was a vertical type in which the straight pipes 1a, 1b, 1c, and 1d were arranged along the vertical direction as in FIG.

The steel sheet was subjected to continuous heat treatment in a heat treatment furnace equipped with this radiant tube. That is, the furnace temperature 950
36 ° C (maximum temperature of radiant tube 1100 ° C)
The heat treatment was performed for 0 hours, and then the operation was stopped for 48 hours (the temperature in the furnace was at room temperature). The radiant tube could be used without any trouble. Even after 12 months, the radiant tube was bent or cracked. Was not found.

The apparatus having the structure shown in FIGS. 4 to 11 was also examined, and in each case, the same result as the apparatus shown in FIGS. 1 to 3 was obtained.

[0028]

According to the present invention, the support of the radiant tube and the receiving object can easily and smoothly move to each other, so that the support can easily move on the receiving object even if the radiant tube undergoes thermal expansion or thermal contraction. To absorb thermal expansion and thermal contraction. Therefore, deformation and cracking of the radiant tube can be suppressed, and the life thereof can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a front view of a vertical W-type radiant tube.

FIG. 2 is a front view showing a specific example of the radiant tube support device of the present invention.

FIG. 3 is a bottom view of the radiant tube support device shown in FIG. 2;

FIG. 4 is a front view showing another specific example of the radiant tube support device of the present invention.

FIG. 5 is a plan view of the radiant tube support device shown in FIG. 4;

FIG. 6 is a front view showing another specific example of the radiant tube support device of the present invention.

FIG. 7 is a plan view of the radiant tube support device shown in FIG. 6;

FIGS. 8A to 8C are diagrams showing another specific example of the radiant tube support device of the present invention.

FIGS. 9A to 9C are diagrams showing another specific example of the radiant tube support device of the present invention.

FIGS. 10A to 10C are diagrams showing another specific example of the radiant tube support device of the present invention.

FIGS. 11A to 11C are diagrams showing another specific example of the radiant tube support device of the present invention.

[Explanation of symbols]

 1a, 1b, 1c, 1d Straight pipe 2, 2a, 2b, 2c Curved pipe 3 Support 4 Receptacle 5 Furnace wall 6 Roller 7 Shaft 8 Groove 9 Washer 10 Sphere 11 Stopper 12 Roller 13 Rail 14 Annular recess

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minoru Sakamoto 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. 1-chome (without street address) Mizushima Works, Kawasaki Steel Corporation (72) Inventor Masateru Nakano 1-chome, Mizushima-Kawasaki-dori, Kurashiki City, Okayama Prefecture (without street address) Inside Mizushima Works, Kawasaki Steel Corporation (72) Akio Sakurai, inventor 1-chome, Kawasaki-dori, Mizushima, Kurashiki-shi, Pref. (Without address) Inside Mizushima Steel Works, Kawasaki Steel Corporation (72) Inventor Takeshi Hirata 3860, Shimotsuruma, Cho, Yamato-shi, Kanagawa Prefecture 3860 Inside Taihei Metal Industry Co., Ltd. Satoshi Hayashi 3860, Shimotsuruma-ji, Cho, Yamato-shi, Kanagawa Prefecture Inside Taihei Metal Industry Co., Ltd. (72) Inventor Kyujiro Ichiki Shimotsuruma-shi, Yamato-shi, Kanagawa No. 1 3860 Pacific Metal Industry Co., Ltd. in

Claims (6)

[Claims] 1. A rotating member which rolls between the support provided at the end of a bent tube of a radiant tube and a metal support projecting from a furnace wall and supporting the support. A radiant tube support device characterized by the above-mentioned. 2. The radiant tube support device according to claim 1, wherein the receiving object has a concave portion for guiding the rotating member on a surface on which the rotating member rolls. 3. The radiant tube supporting device according to claim 1, wherein the rotating member is a roller. 4. The roller has a roller body that comes into contact with the support and the receiving object, and a shaft that is integral with the roller body and supports the roller body. The support or the receiving object has an opening larger than the size of the shaft. The radiant tube supporting device according to claim 3, further comprising an elongated hole for supporting the shaft before the roller is sandwiched between the support and the receiving object. 5. The radiant tube support device according to claim 1, wherein the rotating member is a sphere. 6. The radiant tube supporting device according to claim 1, wherein the rotating member has a surface treatment layer for preventing seizure.