JP2000171160A - Muffle furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve maintenance property and a thermal efficiency by a method wherein small-size muffles and large-size muffles are connected by superposing them alternately so that the outer peripheral surface of the small- size muffle is placed along the inner peripheral surface of the large-size muffle mutually. SOLUTION: Large-size muffles 1 and small-size muffles 2 are hollow tubular bodies having a semi-circular section and the flat part 3 of the large-size muffle 1 is provided with a receiving part 4 whereby the large-size muffle 1 is connected to the small-size muffle 2 so that internal peripheral surface of the large- size muffle 1 is placed along the small-size muffle 2 and the flat part 3 of the large-size muffle 1 is continuous to the flat part 5 of the small-size muffle 2. According to this method, respective large-size muffles and small-size muffles, which are constituting the muffle, can be removed individually whereby the maintenance property is improved and a thermal expansion can be released when the thermal expansion is generated in the muffles. Accordingly, rotary rollers become unnecessary and a thermal efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffle used for heat-treating an object to be heated, such as a substrate for a solar cell, a light-emitting element for displaying a large image, and a muffle furnace including the muffle.

[Prior art]

A conventionally used muffle is, for example, a metal hollow cylinder having a semicircular cross section whose schematic perspective view is shown in FIG. Such a muffle has the advantage that the structure is simple and uniform heating is possible inside the muffle. Also, for example, it is made of metal such as iron and stainless steel, ceramics, etc.
Those having a length of up to m are used. However, it is divided into units of 4 to 5 m due to restrictions in transporting trucks and the like, and the flanges provided on the muffle are firmly connected to each other with bolts and nuts when used. Here, FIG. 6 shows a schematic longitudinal sectional view of a muffle furnace using the conventional muffle shown in FIG. Reference numeral 51 denotes a conventional muffle shown in FIG. 5, which is fixed to a frame 52 at one end 57 by, for example, a bolt and a nut 57. Further, at the opposite end or at an intermediate support point (not shown) required to suppress the deflection of the muffle due to its own weight to a predetermined size or less, the muffle is supported by the rotating roller 53 to reduce the thermal expansion of the muffle. It has a mechanism to escape. In FIG. 6, the flange of the muffle,
The display of bolts and nuts is omitted. This thermal expansion varies depending on the conditions of the heat treatment, the type of the object to be heated, the atmosphere in the muffle, and the like. For example, in a stainless steel muffle, about 1% of the original length at 600 ° C. Indicates elongation. Therefore, the rotating roller 53
Is an essential component of the muffle furnace. Then, the muffle furnace is constituted by combining the heater 54, the heat insulating material 55, and, for example, a conveyor-type heated object transfer means 56.

[0003]

However, when any trouble occurs in the muffle, there is a problem that only a countermeasure can be taken from the entrance or exit of the muffle, and a long time is required for recovery. That is, it has been desired to improve maintainability in order to shorten the recovery time. Also, the rotating roller installed to release the thermal expansion of the integral muffle usually consists of ball bearings, cam followers, etc., and cannot be used in high temperature atmospheres due to heat resistance. (For example, 150 ° C. when the rotating roller is made of steel ball bearings)
There is a problem that cooling is required to keep the temperature below. This need for cooling causes a reduction in thermal efficiency and goes against the demand for energy savings. Then, an object of the present invention is to provide a muffle and a muffle furnace excellent in maintainability and thermal efficiency.

[0004]

SUMMARY OF THE INVENTION The present invention provides a large muffle divided perpendicularly to the longitudinal direction and a small muffle having a cross section smaller than the large muffle at each end. The present invention relates to a muffle that is alternately overlapped and connected so that an inner peripheral surface of the muffle is along the muffle. In this case, both ends of the large muffle are folded inward so as to contact the outer peripheral surface of the small muffle, and both ends of the small muffle are folded outward so as to contact the inner peripheral surface of the large muffle. Is preferred.
The present invention also relates to a muffle furnace including the muffle. In this muffle furnace, it is preferable that one side of the large muffle and the small muffle is fixed and the other end is free. Further, in the muffle furnace of the present invention, it is preferable to form a unit by providing an installation frame in each of the large and small muffles.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a large muffle divided vertically in a longitudinal direction and a small muffle having a cross section smaller than the large muffle at each end.
The muffle is formed by alternately overlapping and connecting the outer peripheral surface of the small muffle and the inner peripheral surface of the large muffle. That is, the muffle according to the present invention is obtained by dividing a conventionally used muffle having a long and continuous integral structure vertically in the longitudinal direction and connecting the divided individual muffles.

FIG. 1 is a schematic perspective view showing an embodiment of the muffle of the present invention. The large muffle 1 and the small muffle 2 constituting the muffle of the present invention shown in FIG. 1 are hollow cylinders having a semicircular cross section. By providing the storage portion 4 on the flat portion 3 of the large muffle 1,
The large muffle 1 and the small muffle 2 are connected so that the inner peripheral surface of the large muffle 1 is along the outer peripheral surface of the small muffle 2 and the plane portion 3 of the large muffle 1 and the plane portion 5 of the small muffle 2 are continuous. I have. At this time, when the size of the plane portion 3 and the plane portion 5 in the longitudinal direction is adjusted and the large muffle 1 and the small cylinder muffle 2 are connected, a small gap that can absorb thermal expansion may be provided. When this gap is a problem, when the muffle of the present invention is incorporated into a muffle furnace, for example, a flat plate larger than the gap may be arranged on the back surface of the flat portion of the muffle to close the gap. Such a design change can be appropriately made by a person skilled in the art as needed. In particular, the flat plate is preferably made of the same material as the cylinder constituting the muffle, but similar effects can be expected with other materials having a small coefficient of thermal expansion.

As described above, the most significant feature of the muffle of the present invention is that the large muffle 1 and the small muffle 2 are not closely connected to each other at the connection portion by welding or the like. As a result, the individual large muffles and small muffles that constitute the muffle can be separately removed, so that maintenance is improved, and even when the muffle expands thermally, there is no interference between the cylinders. Can escape thermal expansion. Therefore, when a muffle furnace is manufactured using the muffle of the present invention, the rotating roller used in the conventional muffle furnace becomes unnecessary, and a decrease in the thermal efficiency generated for cooling the rotating roller is eliminated, and the thermal efficiency is improved. It has the effect of being able to do so.

Further, in the muffle of the present invention, both ends of the large muffle are folded inward so as to contact the outer peripheral surface of the small muffle, and both ends of the small muffle contact the inner peripheral surface of the large muffle. It is preferable to be folded outward. FIG. 2 is a schematic perspective view, partially cut away, of another embodiment of the muffle of the present invention. When the large muffle 1 and the small muffle 2 in this case are connected, the outer folded portion 6 of the large muffle 1
Is in contact with the inner peripheral surface of the small muffle 2. Further, the inner folded portion 7 of the small muffle 2 is in contact with the outer peripheral surface of the large muffle 1. By adopting such an aspect, connection of the respective cylinders constituting the muffle of the present invention becomes easy. Further, particularly when the inside of the muffle is made to have a special atmosphere such as nitrogen gas, hydrogen gas or the like, the folded portion becomes a flow path resistance for the gas constituting the atmosphere, and the atmosphere is easily maintained. This has the effect.

There is no particular limitation on the material forming such a muffle cylinder (large muffle and small muffle) as long as it has been conventionally used as a material of the muffle. For example, stainless steel, iron, Metals such as a nickel-chromium alloy (for example, Inconel 601 manufactured by Daido Steel Co., Ltd.), ceramics, heat-resistant glass, and carbon are exemplified. The cross-sectional shapes of the large muffle and the small muffle are semicircular in the figure, but there is no particular limitation as long as the object to be heated can pass through the inside,
For example, a semicircular shape, a square shape, a rectangular shape, a circular shape, and the like can be given. The length of the large and small muffles is
There is no particular limitation as long as the internal maintenance is easy according to the size and shape of the cross section. The large muffle and the small muffle in the present invention can be manufactured in the same manner as the conventional muffle, for example, by welding. Further, the muffle of the present invention is formed by connecting the large muffle and the small muffle, but the number of each muffle is not particularly limited.

[0010] The present invention also relates to a muffle furnace using the above muffle. In the muffle of the present invention, it is preferable that one side of the large muffle and the small muffle is fixed and the other end is free. Usually, the muffle furnace includes a muffle, a heater, a heat insulating material, and a means for conveying an object to be heated.

Next, a muffle furnace using the muffle of the present invention will be described with reference to the drawings. FIG. 3 is a schematic longitudinal sectional view of a muffle furnace using the muffle of the present invention. As shown in FIG. 3, the muffle furnace of the present invention may be the same as the conventional one, except that the use of the above-mentioned muffle eliminates the need for a conventionally required rotating roller. As a result, as described above, the cooling step of the rotating roller can be omitted, and a decrease in thermal efficiency can be prevented, and thermal efficiency can be improved. As shown in FIG. 3, in the muffle furnace of the present invention, a large muffle 31 having a semicircular cross-section and a small muffle 32 having a semicircular cross-section smaller than the large muffle 31 are each placed in a longitudinal direction. At the end, the inner peripheral surface of the large muffle 31 is connected to each other along the outer peripheral surface of the small muffle 32, and the large muffle 31 and the small muffle 32 are detachable from each other at at least one connection portion. It is. Further, in the muffle furnace shown in FIG. 3, the bottom plate, which is a plane portion of the muffle, is divided and arranged with a gap 33 small enough to absorb thermal expansion. Further, if the semicircular portion and the planar portion of the muffle are divided, the maintainability can be further improved. The other components such as the heater 34, the heat insulating material 35, and the object-to-be-heated conveying means 36 may be the same as those of the conventional muffle furnace.

Next, in the muffle furnace of the present invention,
It is preferable that an installation frame is provided for each of the large muffle 1 and the small muffle 2 to form a unit. By adopting such a unit configuration, a muffle furnace can be configured by combining muffle units according to the process conditions required for an object to be heated. An effect is provided that a muffle furnace can be provided. At this time, the large muffle and the small muffle may be fixed to the installation frame by a conventional method such as driving of bolts and nuts or positioning pins, but when combining the units, the adjacent installation frames and / or cylinders are combined. The bodies may be fixed to each other.

FIG. 4 is a schematic longitudinal sectional view of a muffle furnace in which an installation frame is provided for each of the large and small muffles to form a unit. At this time, the large muffle and the small muffle may be fixed to the installation frame by a conventional method as described above, and when combining the units, the adjacent installation frames may be fixed to each other. In FIG. 4, reference numeral 41 denotes the large muffle,
2 is a small muffle having a semicircular cross section smaller than the large muffle 41. 43 is an installation frame installed for each of the large muffle and the small muffle,
With such a unit configuration, a muffle furnace can be configured by combining the units according to the process conditions required for the object to be heated. Therefore, as described above, there is an effect that the muffle furnace can be supplied in a short period of time and at low cost without complicated steps. In the muffle furnace shown in FIG. 4, the bottom plate, which is a plane portion of the muffle, is divided into small gaps 43 that can absorb thermal expansion.
Are arranged with a gap. Note that the other components such as the heater 44, the heat insulating material 45, and the object to be heated transport means 4
As for No. 6, it may be the same as the conventional muffle furnace.

If the space between the large muffle and the small muffle is open to thermal expansion, all the large and small muffles may be fixed to the installation frame.

[0015]

As described above, according to the muffle and the muffle furnace of the present invention, advantageous effects such as improvement of maintainability and improvement of thermal efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing one embodiment of a muffle of the present invention.

FIG. 2 is a schematic perspective view showing another embodiment of the muffle of the present invention.

FIG. 3 is a schematic longitudinal sectional view of a muffle furnace using the muffle of the present invention.

FIG. 4 is a schematic vertical sectional view of a muffle furnace of the present invention in which an installation frame is provided for each of a large muffle and a small muffle to form a unit.

FIG. 5 is a schematic perspective view of a conventional muffle.

FIG. 6 is a schematic vertical sectional view of a muffle furnace using a conventional muffle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Large muffle 2 Small muffle 3, 5 Plane part 4 Storage part 6 Outside folded part 7 Inner folded part 31, 41 Large muffle 32, 42 Small muffle 33, 43 Gap 34, 44 Heater 35, 45 Heat insulator 36, 46 Cover Heated object transporting means 37, 47 Frame 51 Conventional muffle 52 Frame 53 Rotary roller 54 Heater 55 Insulating material 56 Heated object transporting means 57 Bolt and nut

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Maoto Morita 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 4K061 AA01 BA11 CA09 CA18

Claims (5)

[Claims] 1. A large muffle divided vertically in a longitudinal direction and a small muffle having a cross section smaller than the large muffle, and an outer peripheral surface of the small muffle and an inner peripheral surface of the large muffle extend along respective ends. Like this, a muffle that is connected by overlapping and alternating. 2. Both ends of the large muffle are folded inward so as to contact the outer peripheral surface of the small muffle, and both ends of the small muffle are folded outward so as to contact the inner peripheral surface of the large muffle. The muffle according to claim 1. 3. A muffle furnace comprising the muffle according to claim 1. 4. The muffle furnace according to claim 3, wherein one of the large muffle and the small muffle is fixed and the other end is free. 5. The muffle furnace according to claim 3, wherein an installation frame is provided for each of the large muffle and the small muffle to form a unit.