JP2023082488A - Furnace - Google Patents

Abstract

To provide a furnace having a novel structure capable of retarding heat degradation of a sealing member disposed around an opening.SOLUTION: A roller hearth-type furnace 1 includes: an opening 9 formed in a furnace body 5; a seal member 16 provided in a peripheral part of the opening 9 and surrounding the opening 9; and a furnace door 25 that moves up and down in a vertical direction and opens/closes the opening 9. The furnace door 25 includes a frame member 27 having a first face 27a that contacts the seal member 16 when the opening 9 is closed and a second face 27b extending in a direction intersecting the first face 27a inside the first face 27a. At least part of a heat insulating material that covers the second face 27b is configured of a blanket-like heat insulating material 30b having flexibility, and the blanket-like heat insulating material 30b is arranged flush with respect to the first face 27a.SELECTED DRAWING: Figure 3

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating furnace, and more particularly to a heating furnace characterized by technical means for suppressing thermal deterioration of seal members arranged around openings.

2. Description of the Related Art In a heating furnace used in the steel industry, there is a case where a furnace door for preventing heat radiation is provided at an opening formed in a furnace body through which a heat-treated object is carried in and/or carried out. In this case, a sealing member is used around the opening so as to keep the inside of the furnace airtight by coming into contact with the furnace door.

As a method for protecting the seal member from heat, there is a method of directly or indirectly cooling the seal member using cooling water (refrigerant) (see, for example, Patent Document 1 below). However, the method of using cooling water to cool the seal members causes a decrease in the temperature inside the reactor due to leaks in the cooling water pipes, failure of peripheral equipment, clogging of the cooling water pipes, a decrease in the amount of water and the resulting shutdown of the reactor. There are so many problems such as freezing of cooling water in Cooling water is also a cause of lowering the thermal efficiency in the furnace.

JP 2020-169735 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heating furnace with a novel structure capable of suppressing thermal deterioration of a sealing member arranged around an opening.

The heating furnace according to the first aspect of the present invention is defined as follows. Namely
an opening formed in the furnace body for loading and/or unloading the object to be heat treated;
a sealing member provided at the periphery of the opening and surrounding the opening;
a furnace door that moves vertically to open and close the opening;
A heating furnace comprising
The furnace door includes a frame member having a first surface that contacts the seal member when the opening is closed, and a second surface that extends inside the first surface in a direction intersecting the first surface, and ,
At least part of the heat insulating material covering the second surface is composed of a blanket-like heat insulating material having flexibility, and the blanket-like heat insulating material is provided flush with the first surface.

According to the heating furnace of the first aspect defined in this way, since the second surface side of the frame member in contact with the seal member is covered with the heat insulating material, the heat in the furnace is sealed through the frame member of the furnace door. It is possible to suppress heat deterioration of the sealing member arranged around the opening by suppressing the temperature rise of the sealing member due to the heat being transmitted to the member.
Here, when the heat insulating material on the furnace door side is provided flush with the first surface, the gap between the facing furnace shell member on the furnace body side and the heat insulating material on the furnace door side becomes small. For this reason, in the heating furnace of the first aspect, even if the heat insulating material on the furnace door side comes into contact with the furnace shell member on the furnace body side when the furnace door is raised and lowered, the heat insulating material is made flush with the first surface so that the heat insulating material is unlikely to be damaged. A flexible blanket-like heat insulating material is provided at the position.

A second aspect of the invention is defined as follows. Namely
In the heating furnace specified in the first aspect, the blanket-shaped heat insulating material provided on the furnace door has a thermal conductivity of 0.045 at 600 ° C. on the back side opposite to the opening side. W/m/K] or less is provided so as to cover the second surface.
According to the heating furnace of the second aspect defined in this way, it is possible to further suppress the rise in temperature of the sealing member due to the effect of the low thermal conductivity heat insulating material.

A third aspect of the present invention is defined as follows. Namely
In the heating furnace specified in the second aspect, the lower sealing member provided below the opening and the lower frame member of the furnace door in contact with the lower sealing member are disposed between the two adjacent rollers for conveying the heat-treated material. placed in between.
When the low thermal conductivity heat insulating material is used as described above, the heat insulating effect is high and the furnace door can be made compact. It is possible to easily realize a layout in which it is arranged between the rollers for conveying the heat-treated material.

A fourth aspect of the present invention is defined as follows. Namely
In the heating furnace specified in any one of the first to third aspects, the open closing surface of the furnace door has a recessed shape in which the central region where the blanket-like heat insulating material is not provided is recessed.
According to the heating furnace of the fourth aspect defined in this way, it is possible to secure a gap between the furnace shell member on the furnace body side and the central region of the furnace door, which has a relatively small effect of suppressing the temperature rise of the seal member. It is possible to avoid contact with the furnace shell member on the furnace body side in such a central region.

A fifth aspect of the present invention is defined as follows. Namely
In the heating furnace specified in any one of the first to fourth aspects, the blanket-shaped heat insulating material is connected to the steel shell via studs,
A recess is formed in the blanket-shaped heat insulating material, and the tip end of the stud is accommodated in the recess.
According to the heating furnace of the fifth aspect defined in this way, it is possible to avoid contact between the tip end of the stud and the furnace shell member on the furnace body side.

A sixth aspect of the present invention is defined as follows. Namely
In the heating furnace specified in any one of the first to fifth aspects, the heat insulating material on the furnace body side located between the seal member and the opening is positioned above the seal member mounting surface to which the seal member is mounted. When the furnace door is closed, the heat insulating material on the furnace body side is brought into contact with the furnace door.
According to the heating furnace of the sixth aspect defined in this way, it is possible to eliminate (or significantly reduce) the gap in the heat insulating material that shields the space between the opening and the sealing member when the furnace door is closed. , the increase in temperature of the sealing member can be further suppressed.

1 is a diagram showing a schematic configuration of a roller hearth-type heating furnace according to one embodiment of the present invention; FIG. It is the perspective view which separated and showed the opening periphery part and the furnace door of the furnace body in the same heating furnace. FIG. 3 is a cross-sectional view showing the opening periphery of the furnace body and the furnace door in the same heating furnace. A view showing the furnace door alone, (A) is a front view seen from the side of the closed opening, (B) is a BB cross-sectional view of (A), and (C) is a CC cross-sectional view of (A). is. It is explanatory drawing of the opening-and-closing operation|movement of the furnace door in the same heating chamber. FIG. 6 is an explanatory diagram of the opening/closing operation of the furnace door continued from FIG. 5; (A) is a heat pattern when investigating the temperature distribution of the seal member temperature and the heat-treated object. (B) is a diagram showing measurement points when investigating the seal member temperature. It is the figure which showed the measurement location at the time of investigating the temperature distribution of the to-be-heat-processed object. It is the figure which showed the modification of the same embodiment.

Embodiments of the present invention will now be described in detail below.

FIG. 1 shows a schematic configuration of a roller hearth type heating furnace according to one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a roller hearth type heating furnace (hereinafter sometimes simply referred to as a heating furnace) for heat-treating objects to be heat-treated such as steel and ceramics placed on trays.
In the following, as shown in FIG. 1, the vertically upward direction is defined as the upward direction, the vertically downward direction is defined as the downward direction, and the downstream side of the direction in which the object W to be heat-treated W is carried (inserted) into the heating furnace 1 is defined as the forward direction. , the upstream side of the direction in which the object W to be heat-treated is carried into the heating furnace 1 is defined as the rearward direction.

As shown in FIG. 1, the heating furnace 1 has a furnace body 5 made of steel. The furnace body 5 has a heat-resistant heat insulating material 6 inside, and the heat insulating material 6 constitutes a heat insulating wall 7 . The inside of the heat insulating wall 7 is a heating chamber 10 for accommodating the object W to be heat-treated, and the heating chamber 10 is provided with a burner 12 and a stirring fan 14 as heating means. An opening 9 is formed on the right side of the furnace body 5 in the figure for loading and unloading the object W to be heat treated.

A plurality of conveying rollers 20 are arranged side by side in the front-rear direction, which is the conveying direction, inside the heating chamber 10 and in the area outside the furnace near the opening 9 . In the figure, 21 is a driving motor for rotating the roller 20 . By rotating the drive motor 21 forward, the object W to be heat treated is carried into the furnace, and by rotating the drive motor 21 in the reverse direction, the object W to be heat treated is carried out of the furnace.

The opening 9 is provided with a furnace door 25 which is moved up and down by an opening/closing device 24 to open and close the opening 9 . In FIG. 1, the closed furnace door 25 is indicated by a solid line, and the open furnace door 25 is indicated by a chain double-dashed line.

A pressing device 17 is provided near the furnace door 25 . Based on a driving force from a motor (not shown) or the like, the link 17b swings around the rotating shaft 17a, and the closed furnace door 25 is pressed toward the opening 9. As shown in FIG.

FIG. 2 is a perspective view showing the opening periphery of the furnace body 5 and the furnace door 25 separated from each other. FIG. 3 is a sectional view showing the opening peripheral portion of the furnace body 5 and the furnace door 25 separated from each other.
As shown in FIG. 2, a seal member 16 is attached to the periphery of the opening 9 formed in the furnace body 5 so as to surround the opening 9 so as to contact the furnace door 25 to keep the inside of the furnace airtight. there is Specifically, as shown in FIG. 3, the seal member 16 is attached to the seal member mounting surface 41a of the metal furnace shell member 41 arranged around the opening 9. As shown in FIG.
In this example, a rope-like sealing member made of heat-resistant ceramic fiber and rubber binder is used as the sealing member 16 . The heat resistance temperature of the seal member 16 is approximately 500.degree.

Next, the construction of the furnace door 25 that closes the opening 9 will be described. The furnace door 25 includes a frame member 27, a steel shell 28, and a heat insulating material portion 30, and as a whole has a substantially square plate shape as shown in FIG. When the furnace door 25 is viewed from the side, the steel shell 28 near the lower side (lower frame member 34) of the frame member 27 is tapered so as not to interfere with the rollers 20 positioned on the rear side (FIGS. 1 and 2). See Figure 5).

The frame member 27 is a square frame-shaped annular body using a square tubular metal pipe, and is integrally joined to the peripheral edge of the steel shell 28 . As shown in FIG. 3, the frame member 27 has a first surface 27a that faces the seal member 16 on the furnace body side and contacts the seal member 16, and the inside of the first surface 27a (the side facing the center of the furnace door 25). It has a second surface 27b perpendicular to the first surface 27a.

As shown in FIG. 3, the heat insulating material part 30 includes a plurality of heat insulating materials 30a, 30b, 30a, 30b, 30b, 30b, 30b, 30b, 30b, 30b, 30b, 30b, 30b, 30b, 30b, 30b, 30, 30, 30, 30, 30, 3, 3, 4, 4, 5, 5, 5, respectively. 30c and 30d are laminated to close the opening 9 of the furnace body 5 when the furnace door is closed.
Materials for these heat insulating materials are not particularly limited, but may be refractories with a high porosity, ceramic fibers or ceramic particles in the form of a board or a flexible blanket.

As shown in FIG. 3, the heat insulating material part 30 is arranged so as to cover the second surface 27b of the frame member 27 in the peripheral region 31 near the frame member 27. As shown in FIG. Specifically, the heat insulating material is provided up to the height flush with the first surface 27a of the frame member 27 so as to cover up to the corner where the first surface 27a and the second surface 27b of the frame member 27 intersect. This is because if the second surface 27b of the frame member 27 is exposed, the frame member 27 is heated through the exposed portion, and the temperature of the seal member 16 in contact with the frame member 27 is increased.

In this example, as the heat insulating material covering the second surface 27b of the frame member 27, a low thermal conductivity heat insulating material 30a having a thermal conductivity of 0.045 [W/m/K] or less at 600° C. is used. By doing so, it is possible to satisfactorily suppress the transfer of the temperature of the heating chamber 10 to the frame member 27 . The thermal conductivity of the heat insulating materials 30b, 30c, and 30d other than the low thermal conductivity heat insulating material 30a used in this example is 0.15 to 0.25 [W/m/K] at 600.degree.
As the low thermal conductivity heat insulating material 30a, for example, a heat insulating material having a microporous structure in which ceramic particles of micron order or less are used to reduce the size of voids between particles can be used. The low thermal conductivity heat insulating material with microporous structure has the problem that it is fragile and easily cracked compared to other heat insulating materials. Therefore, in this example, the surface of the low thermal conductivity heat insulating material 30a is covered with a blanket-like heat insulating material 30b to prevent the low thermal conductivity heat insulating material 30a from being damaged.

On the other hand, in a region inside (near the center) of the low thermal conductivity heat insulating material 30a, a blanket heat insulating material 30d is laminated, and a board-like heat insulating material 30c is laminated on the surface thereof. The board-shaped heat insulating material 30c is laminated so as to be flush with the low thermal conductivity heat insulating material 30a. The periphery of the board-like heat insulating material 30c is further covered with a blanket-like heat insulating material 30b. As a result, the opening closing surface 26 of the furnace door 25 is recessed in the central region 32 where the blanket-shaped heat insulating material 30b is not arranged with respect to the peripheral region 31 where the blanket-shaped heat insulating material 30b is arranged. It has a concave shape.

As shown in FIG. 3, these laminated heat insulating materials 30a, 30b, 30c, and 30d are connected via studs 35 having one end joined to the steel shell 28. As shown in FIG. More specifically, a flange member 36 is screwed to a tip end portion 35 b of the stud 35 extending toward the furnace body 5 , and a heat insulating material is sandwiched between the steel shell 28 and the flange member 36 . In this example, a recess 37 is formed in the blanket-shaped heat insulating material 30b, and the tip end 35b of the stud 35 is accommodated in the recess 37. As shown in FIG. This is to prevent the front end portion 35b of the stud 35 from interfering with the furnace shell member when the furnace door is raised and lowered.

The structure of the furnace door 25 has been described above by taking the upper portion and the lower portion of the furnace door 25 shown in FIG. 3 as examples. The right part has similar features.

Next, the heat insulating material provided near the opening 9 on the furnace body 5 side will be described. As shown in FIG. 3, on the side of the furnace body 5, a heat insulating material is provided so as to block the space between the furnace shell member 41 to which the seal member 16 is attached and the heating chamber 10 and between the furnace shell member 41 and the opening 9. is provided. As in the case of the furnace door 25, part of the heat insulating material is a low thermal conductivity heat insulating material 42a having a thermal conductivity of 0.045 [W/m/K] or less at 600°C.
In the furnace shell member above the opening 9 , the low thermal conductivity heat insulating material 42 a has a plate-like cross-sectional shape extending in the horizontal direction (front-rear direction) between the opening 9 and the furnace shell member 41 . On the other hand, in the furnace shell member below the opening 9, the low thermal conductivity heat insulating material 42a extends vertically between the furnace shell member 41 and the heating chamber 10, and extends horizontally between the opening 9 and the furnace shell member 41. It has a substantially T-shaped cross section extending in the front-rear direction. In this example, considering the difference in thickness of the heat insulating material 42c, the cross-sectional shape of the low thermal conductivity heat insulating member 42a is different between the upper side and the lower side of the opening 9. For example, the partial enlargement of FIG. As shown in the figure, the cross-sectional shape of the low thermal conductivity heat insulating member 42a on the upper side can be substantially T-shaped in cross-sectional view, like the lower side. Moreover, depending on the case, it is also possible to make both of them plate-shaped in cross section.
The low thermal conductivity heat insulating material 42a is laminated with other blanket-like heat insulating materials 42b, 42c, etc., and one end thereof is connected to a steel shell (not shown) via a stud 35. As shown in FIG.

5 and 6 are explanatory views of the opening and closing operation of the furnace door 25 in the heating furnace 1. FIG.
As shown in FIG. 5, in the heating furnace 1 of this embodiment, a lower sealing member 19 provided below the opening 9 is provided between two adjacent conveying rollers 20,20.
When the object W to be heat treated is carried in and out, the furnace door 25 once raised to the position indicated by the two-dot chain line in FIG. descends downward to a predetermined position facing the opening 9 . At this time, the lower frame member 34 of the furnace door 25 contacting the lower seal member 19 is positioned between the two adjacent conveying rollers 20,20.

Thereafter, the link 17b of the pressing device 17 (see FIG. 1) presses the furnace door 25 toward the opening 9 as shown in FIG. It comes into contact with the member 16 to ensure airtightness in the furnace. At this time, since the space between the heating chamber 10 and the opening 9 and the sealing member 16 is shielded by the heat insulating material except for the gap δ, the temperature of the sealing member 16 is suppressed from increasing due to the heat from the inside of the furnace.

Next, the result of investigating the seal member temperature in the heating furnace 1 and the temperature distribution of the heat-treated object W being heat-treated in the heating chamber will be described.
The temperature of the sealing member was investigated by heating the inside of the heating chamber 10 in the N ₂ atmosphere with the heat pattern shown in FIG. The temperature measurement points P were eight points indicated by black circles in FIG. 7B, and the temperature was measured using a sheathed thermocouple.
As a result of investigation, the maximum temperature at each measurement point was 149° C. to 234° C., which was sufficiently low for the heat resistance temperature of 500° C. of the seal member 16 .

Investigation of the temperature distribution of the heat-treated object W was performed by inserting a total of 10 heat-treated objects (wire coils) W stacked in two stages in the heating chamber 10 as shown in _FIG . The chamber was heated according to the heat pattern shown in FIG. 7A, and the temperature distribution of the object W to be heat-treated was confirmed at the final stage of soaking held at 900°C. The temperature measurement points P were 12 points indicated by black circles in FIG. 8, and the temperature was measured using a sheathed thermocouple.
As a result of the investigation, the width of temperature variation at the 12 measurement points was 6.6°C.
Under the same conditions, when adopting a water cooling system in which water is circulated inside the frame member 27 on the side of the furnace door 25 that contacts the seal member 16 to cool the seal member 16, the temperatures at the 12 measurement points are Since the range of variation was 8.1 to 9.2° C., it can be said that the configuration of this embodiment, which suppresses the temperature of the seal member 16 without water cooling, is also excellent in terms of temperature uniformity. I understand.

As described above, according to the heating furnace 1 of the present embodiment, the second surface 27b side of the frame member 27 in contact with the seal member 16 is covered with the heat insulating material, so that the heat in the furnace is transferred to the frame member 27 of the furnace door 25. It is possible to suppress heat deterioration of the sealing member 16 arranged around the opening 9 by suppressing the temperature rise of the sealing member 16 due to the heat being transmitted to the sealing member 16 through the opening 9 .
Here, in the present embodiment, since the heat insulating material on the side of the furnace door 25 is provided flush with the first surface 27a, the gap between the heat insulating material and the furnace shell member on the facing side of the furnace body becomes small. For this reason, in this embodiment, even when the furnace door 25 comes into contact with the furnace shell member on the furnace body side when the furnace door is raised and lowered, the heat insulating material is not easily damaged. A blanket-shaped heat insulating material 30b is provided.

According to the heating furnace of the present embodiment, the blanket-like heat insulating material 30b provided on the furnace door 25 has a thermal conductivity of 0.045 [W/ m/K] or less is provided so as to cover the second surface 27b.

When the low thermal conductivity heat insulating material 30a is used, the heat insulating effect is high and the furnace door 25 can be configured compactly. It is possible to easily realize a layout in which it is arranged between the transport rollers 20 , 20 .

According to the heating furnace of the present embodiment, as shown in FIG. 3, the central region 32 of the opening closing surface 26 of the furnace door 25, where the blanket-like heat insulating material 30b is not provided, has a recessed shape. . For this reason, the central region 32, which has a relatively small effect of suppressing the temperature increase of the seal member 16, can secure a gap with the furnace shell member on the furnace body 5 side, and the furnace shell on the furnace body side in the central region 32. Contact with members can be avoided.

FIG. 9 shows a modification of the above embodiment.
In this example, as shown in FIG. 9A, the heat insulating materials 42a and 42b on the furnace body 5 side located between the seal member 16 and the opening 9 are attached to the seal member mounting surface to which the seal member 16 is mounted. The heat insulating members 42a and 42b protrude further toward the furnace door 25 than 41a, so that the end surfaces 50 of the heat insulating members 42a and 42b can come into contact with the furnace door 25 when the furnace door is closed as shown in FIG. 9(B).
In this way, the gap δ (see FIG. 6) between the edge of the opening 9 and the furnace door 25 that existed in the above embodiment can be eliminated, so that the temperature of the sealing member 16 can be further prevented from increasing. can be suppressed.

Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, as the frame member of the furnace door that comes into contact with the sealing member, it is possible to use a solid rectangular member or a plate member bent into an L-shape instead of a rectangular tubular member. In addition, the above embodiment is an example in which one opening is provided in the furnace body, but the present invention can also be applied to a continuous heating furnace provided with two openings for loading and unloading. The present invention can be configured in various forms without departing from the gist of the invention.

1 Roller Hearth Type Heating Furnace 5 Furnace Body 9 Opening 16 Sealing Member 20 Roller for Transporting Material to be Heat Treated 25 Furnace Door 27a First Surface 27b Second Surface 28 Steel Shell 30 Heat Insulating Material Part 30a Low Thermal Conductivity Insulating Material 30b Blanket-like Insulating Material 31 Peripheral region 32 Central region 35 Stud 35b Tip end 37 Recess 41a Seal member mounting surface 42a Low thermal conductivity heat insulating material W Object to be heat treated

Claims (6)

an opening formed in the furnace body for loading and/or unloading the object to be heat treated;
a sealing member provided at the periphery of the opening and surrounding the opening;
a furnace door that moves vertically to open and close the opening;
A heating furnace comprising
The furnace door includes a frame member having a first surface that contacts the seal member when the opening is closed, and a second surface that extends inside the first surface in a direction intersecting the first surface, and ,
The heating furnace, wherein at least part of the heat insulating material covering the second surface is composed of a blanket-like heat insulating material having flexibility, and the blanket-like heat insulating material is provided flush with the first surface. Low thermal conductivity of 0.045 [W / m / K] or less at 600 ° C. on the back side opposite to the opening side of the blanket-shaped heat insulating material provided on the furnace door 2. The heating furnace according to claim 1, wherein a heat insulating material is provided so as to cover said second surface. 3. The method according to claim 2, wherein a lower sealing member provided below the opening and a lower frame member of the furnace door contacting the lower sealing member are arranged between two adjacent rollers for transporting the heat-treated material. Furnace as described. 4. The heating furnace according to any one of claims 1 to 3, wherein the opening closing surface of the furnace door has a recessed shape in which a central region where the blanket-like heat insulating material is not provided is recessed. The blanket-shaped heat insulating material is connected to the steel shell via studs,
The heating furnace according to any one of claims 1 to 4, wherein a recess is formed in said blanket-shaped heat insulating material, and the tip end of said stud is accommodated in said recess. The heat insulating material on the furnace body side located between the seal member and the opening is made to protrude toward the furnace door side from the seal member mounting surface on which the seal member is mounted, and when the furnace door is closed, the heat insulation material is on the furnace body side. The heating furnace according to any one of claims 1 to 5, wherein the heat insulating material of is in contact with the furnace door.

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