JP2002188889A - Muffle-supporting structure of continuous heating furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deformation of a muffle in the width direction and in the vertical direction. SOLUTION: Both ends of support rollers 11 are arranged by being supported on bearings 12 provided on a counter 1 in a manner to be freely peripherally rotatable in the circulation direction of an endless belt 5 at predetermined intervals. The muffle 2 is supported on the rollers 11 longitudinally in agreement with the direction of the arrangement of the rollers 11. When the muffle 2 is thermally expanded/contracted, the support rollers 11 are rotated following the expansion/contraction. Accordingly resistance (frictional resistance) to the expansion/contraction movement and difference in local resistance become substantially zero, and the muffle 2 expands/contracts straightly in the longitudinal direction without deforming in the width direction or vertical direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a muffle support structure for a continuous heating furnace such as a mesh belt type continuous sintering furnace.

[0002]

2. Description of the Related Art FIG. 3 shows a mesh belt type continuous sintering furnace.
Are well known. This sintering furnace has a base 1
(Furnace core tube) 2 is supported by a supporting means composed of a number of piers (posts made of tiled tiles) 3 and a hearth plate (furnace hearth) 4, and the material to be sintered W is placed in the muffle 2. Is carried by an endless belt 5 made of mesh, and oxidation is prevented in an atmosphere gas to continuously perform high-temperature heat treatment.

The hearth plate 4 is made of a heat-resistant material such as silicon carbide and mounted on the pier 3 to receive the muffle 2. Reference numerals 7 and 8 denote rotating wheels on which the endless belt 5 is stretched, and one of the rotating wheels is rotated by a rotary driving device (not shown) so that the endless belt 5
Let go inside.

[0004]

By the way, the muffle 2
Is made of a heat-resistant metal (for example, SUS). When the temperature is raised from a normal temperature before the start of the operation to a processing temperature of about 1120 ° C., the length is increased by thermal expansion. When the temperature is lowered, the length is reduced due to heat shrinkage.

The above expansion and contraction of the muffle 2 is performed on a hearth plate 4 fixed on the pier 3. Muffle 2
However, there is no obstacle if it always linearly expands and contracts on the hearth plate 4 in its longitudinal direction, but the frictional resistance between the muffle 2 and the hearth plate 4 is not necessarily the same over the entire support surface, Rather, since there is a large difference locally, the resistance difference often causes the muffle 2 not to expand and contract linearly in the longitudinal direction.

In such a case, since the muffle 2 is deformed in the width direction or the vertical direction due to expansion and contraction, for example, the positional relationship between the muffle 2 and the endless belt 5 is broken, and the sintering object W is carried into the muffle 2. In addition, various obstacles such as being unable to carry out occur. Since the above-mentioned deformation of the muffle 2 tends to gradually increase with repetition, it is necessary to frequently repair the muffle 2. If this is neglected, the service life will be reduced.

In order to correct the distortion, the muffle 2 is constantly pulled in the longitudinal direction by a cylinder or the like, but there is a problem that the structure becomes complicated.

In view of the above problems, an object of the present invention is to provide a muffle support structure for a continuous heating furnace in which the muffle is unlikely to be deformed in the width direction or the vertical direction due to thermal expansion and contraction. Another object of the present invention is to provide a muffle support structure for a continuous heating furnace having a relatively simple structure.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, an object to be heated, such as an object to be sintered, is carried by an endless belt into a muffle supported by a supporting means. In the continuous heating furnace in which the heating is carried out, the supporting means is constituted by a plurality of supporting rollers which are rotatably arranged in a circumferential direction at required intervals in a longitudinal direction of the muffle.

In this supporting means, when the muffle expands due to thermal expansion due to temperature rise and shrinks due to thermal contraction when temperature falls,
The support roller rotates following the expansion and contraction of the muffle. For this reason, the frictional resistance and the local resistance difference of the muffle with respect to the support roller become negligible, and the muffle expands and contracts linearly without being deformed in the width direction or the vertical direction.

[0011] According to the second aspect of the present invention, the first aspect is provided.
In the muffle support structure for a continuous heating furnace described above, the bearing of each support roller is disposed outside the muffle when viewed in the longitudinal direction of the muffle. With this configuration, the influence of the bearing on the bearing is reduced because the bearing is separated outward from the heating unit, and the durability of the bearing is improved. When the bearing is provided outside the cover covering the muffle, the influence of heat from the heating furnace can be further reduced.

According to the third aspect of the present invention, there is provided the first aspect.
Alternatively, in the muffle support structure for a continuous heating furnace according to 2, the endless belt is a mesh belt. With this configuration, it is possible to greatly reduce the heat interruption trouble caused by the belt, and it is possible to more uniformly heat the entire outer surface of the object to be heated.

[0013]

Embodiments of the present invention will be described with reference to the accompanying drawings. 1 and 2 show an embodiment of a muffle support structure of a continuous heating furnace according to the present invention.

Reference numeral 11 in the drawing denotes a support roller. The support roller 11 is supported at both ends by bearings 12 and 12 provided on the gantry 1, and is rotatable in a circumferential direction at a required interval in a circulating movement direction (a left-right direction in FIG. 1) of the endless belt 5 made of mesh. Are arranged in parallel with each other.

The muffle 2 is supported on the support roller 11 with its longitudinal direction coinciding with the arrangement direction of the support roller 11. Since the bottom 2a of the muffle 2 that contacts the support roller 11 is easily deformed by the load of the muffle 2, measures such as increasing the thickness or adding a reinforcing material are taken as necessary. Each support roller 11 is made of heat-resistant metal, ceramic, silicon carbide, or the like.
Of the support means.

The bearing 12 is provided separately from the muffle 2 outside a cover body 14 provided to cover the muffle 2 in order to reduce the thermal influence of the heating section.

The other structure is the same as that of the conventional continuous sintering furnace shown in FIG. 3, so that the same members and the like are denoted by the same reference numerals and description thereof is omitted.

Next, the operation of the muffle supporting structure of the continuous heating furnace configured as described above will be described. As before, the muffle 2 elongates due to thermal expansion when the temperature rises as described above,
When the temperature is lowered, it shrinks due to heat shrinkage.

When the muffle 2 expands and contracts, each support roller 11 rotates following the expansion and contraction of the muffle 2. Therefore, the expansion and contraction movement resistance (friction resistance) generated between the hearth plate (hearth) 4 and the muffle 2 and the resistance difference between local parts, which are obstacles in the prior art, become substantially zero, and the muffle 2 It expands and contracts linearly in the longitudinal direction without being deformed in the width direction or the vertical direction.

For this reason, there is no hindrance to the conveyance of the object to be heated W such as the object to be sintered by the endless belt 5, and a long-term smooth furnace operation can be expected. Also,
Prevention of thermal deformation of the muffle 2 eliminates the need for frequent maintenance and extends the life of the muffle 2, thereby reducing the overall cost.

Further, since the bearing 12 is located outside the cover body 14, the influence of the heat from the heating section is small, so that the bearing 12 is hardly broken. Therefore, it is not necessary to provide heat resistance, and the cost can be reduced by using a normal bearing.

The specifications such as the number of the supporting rollers 11 are not limited to the illustrated embodiment, but may be changed as appropriate in accordance with the weight and length of the muffle 2. Further, the amount of expansion and contraction movement near the central portion in the longitudinal direction of the muffle 2 is smaller than that at both ends (the exact amount of expansion and contraction movement at the central portion is theoretically zero). It is also possible to select and combine the portions appropriately, for example, by supporting the portion with a pier and a hearth plate as in the conventional case. Further, as the endless belt 5, a transport belt other than the mesh belt type can be used.

The present invention is not limited to the continuous sintering furnace of the above-described embodiment and the like, but can be applied to other continuous heating furnaces.

[0024]

As described above, according to the first aspect of the present invention, the deformation of the muffle in the width direction and the vertical direction due to thermal expansion and contraction can be suppressed. Accordingly, it is possible to provide a muffle support structure for a continuous heating furnace that does not require frequent maintenance and has a long life. Further, the structure can be simplified as compared with a conventional apparatus using a cylinder or the like for correcting the distortion of the muffle.

Further, in the muffle support structure for a continuous heating furnace according to the first aspect, the bearing of each support roller is arranged outside the muffle when viewed in the longitudinal direction of the muffle. This has the effect of reducing the size and improving the durability.

Further, in the muffle support structure for a continuous heating furnace according to the first or second aspect, the endless belt is a mesh belt, so that the entire outer surface of the object to be heated can be more uniformly heated. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a muffle support structure of a continuous heating furnace according to the present invention.

FIG. 2 is a cross-sectional view of a muffle support structure of the continuous heating furnace of FIG. 1 as viewed in a longitudinal direction of the muffle.

FIG. 3 is a cross-sectional view showing a conventional continuous sintering furnace.

[Explanation of symbols]

 Reference Signs List 1 base 2 muffle 2a muffle bottom 3 pier (support) 4 hearth plate (hearth) 5 endless belt 7,8 rotating wheel 11 support roller 12 bearing 14 cover body W object to be heated

Claims (3)

[Claims] 1. A continuous heating furnace in which an object to be sintered such as an object to be sintered is transported by an endless belt into a muffle supported by a supporting means and heated, wherein the supporting means is required in a longitudinal direction of the muffle. A muffle support structure for a continuous heating furnace, comprising a plurality of support rollers arranged side by side so as to be rotatable in the circumferential direction at intervals of. 2. The muffle support structure for a continuous heating furnace according to claim 1, wherein the bearing of each support roller is disposed outside the muffle when viewed in the longitudinal direction of the muffle. 3. The muffle support structure for a continuous heating furnace according to claim 1, wherein the endless belt is a mesh belt.