JPH0861859A - Roller hearth type heat treatment furnace - Google Patents

Abstract

PURPOSE: To provide a roller hearth type heat treatment furnace capable of performing a precise control of a concentration of atmospheric gas, and performing an effective utilization of heat energy. CONSTITUTION: A roller hearth type heat treatment furnace is comprised of a muffle 2 arranged to enclose a transporting passage for an item S to be treated and a hearth roller 3 arranged to be crossed within the muffle 2. It further includes a roller receiving pipe 6 communicated with and connected to each of an outer side surface of the muffle 2 and for storing each of end portions 3a, 3b of a hearth roller 3, and of supporting parts 9, 10 for rotatably and sealingly supporting the end portions 3a, 3b of the hearth roller 3. The supporting parts 9 (10) are constructed such that a roller side graphite parts 13 fixed to the end portions 3a (3b) of the hearth roller 3 and the receiving pipe side graphite parts fixed at the inner surface of the roller receiving pipe 6 are fitted to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller hearth type heat treatment furnace, and more particularly to a support structure for a hearth roller.

[0002]

2. Description of the Related Art Conventionally, a roller hearth type heat treatment furnace (hereinafter referred to as an RH furnace) having a cross-sectional structure shown in FIG. 4 has been used to perform heat treatment such as firing on a ceramic product. That is, this RH furnace is arranged along a furnace body 21 made of a heat insulating material of a predetermined thickness and in a horizontal direction that traverses the inside of the furnace space, and in the longitudinal direction of the furnace body 21 (direction perpendicular to the paper surface). A plurality of hearth rollers 22 arranged in parallel along each other, and a rotary drive device 23 such as an electric motor for rotationally driving each hearth roller 22 protruding at both ends outside the furnace body 21. is there. The rotary drive devices 23 are connected to the drive-side end portions of the hearth rollers 22, respectively, while the anti-drive-side end portions of the hearth rollers 22 are rotatably supported by bearings 24. The processing object S such as a jar is to be transported in the furnace space as the hearth roller 22 rotates. At this time, an amorphous heat insulating fiber 25 for hermetically sealing the inside of the furnace is packed between the furnace body 21 and each hearth roller 22.

Further, this RH furnace includes a gas introducing pipe 26 for introducing an atmospheric gas (or a cooling gas) G into an inner space of the furnace, and an electric heater 27 for heating an object to be processed S being conveyed. And the inner end of the gas introduction pipe 26 that penetrates the furnace body 21 and projects into the furnace interior space is opened toward the furnace interior space. Furthermore, the electric heaters 27 are respectively arranged at the upper and lower positions of the hearth roller 22 and are arranged along the horizontal direction that traverses the furnace interior space, and the atmosphere gas G introduced into the furnace interior space is used. The object S to be processed is heated by all convective heat transfer or direct radiant heat transfer.

[0004]

However, in the RH furnace having the above-mentioned conventional structure, the atmospheric gas G introduced through the gas introducing pipe 26 spreads in a uniform state over the entire space in the furnace. It is difficult to do so, and the concentration distribution and temperature distribution of the atmospheric gas G are likely to vary, which is a disadvantage. Further, since the heat insulating fiber 25 is deformed due to the thermal expansion of the hearth roller 22 and the atmospheric gas G may leak out of the furnace body 21 through the deformed heat insulating fiber 25, the atmosphere introduced into the furnace space may be changed. It has been very difficult to maintain the gas G concentration while adjusting it precisely. Furthermore, the inner surface of the furnace body 21 exposed to high temperature and the electric heater 27
There is also a case where a peeled object from the above is dropped on the object to be processed S, which adversely affects the characteristics of the object to be processed S.

By the way, when it is necessary to precisely control the concentration of the atmospheric gas G, a muffle made of a heat-resistant alloy plate, which is not shown in the drawing, is constructed so as to surround the transportation path of the object S to be processed in the furnace. It is arranged in the space and the atmosphere gas G is introduced into this muffle. However, a mesh belt made of a heat-resistant alloy or the like is generally used as a conveying means of the object S in the heat treatment furnace configured with a muffle, and when the mesh belt is used, the mesh belt itself is a furnace. As a result of repeating the heating inside and the cooling outside the furnace to bring out the heat energy, the heat energy loss is greatly increased. Further, when the hearth roller 22 is used, the transport speed of the object S to be processed can be changed in each predetermined range, and adjustment for obtaining an optimum profile is possible, whereas when the mesh belt is used, Since it is not possible to change the transport speed in each predetermined range, it is difficult to realize the optimum profile.

The present invention was devised in view of these disadvantages. It is possible to precisely control the concentration of the atmospheric gas, improve the concentration distribution and temperature distribution of the atmospheric gas, and improve the thermal energy. R that can realize an optimum profile according to the object to be processed while making effective use
The purpose is to provide an H furnace.

[0007]

The RH furnace according to the present invention comprises:
In order to achieve such an object, a muffle that is arranged so as to surround the conveyance path of the object to be processed and a hearth roller that is arranged so as to traverse the inside of the muffle are provided, and the muffle is connected to each of the outer side surfaces of the muffle. A roller receiving tube that is connected and stores each end of the hearth roller;
And a support component that is attached to each roller receiving tube and that supports the end portion of the hearth roller in a rotatable and airtightly sealable manner. In this case, the supporting component is a fitting of the roller-side graphite component fixed to the end of the hearth roller and the receiving-tube side graphite component fixed to the inner surface of the roller receiving pipe.

[0008]

According to the above construction, since the muffle is used, the concentration of the atmospheric gas can be precisely controlled, so that the concentration distribution and the temperature distribution of the atmospheric gas can be made uniform. Further, since the object to be processed is carried by using a large number of hearth rollers, not only it is possible to change the carrying speed of the object to be processed in each predetermined range, but also it is possible to suppress the heat energy loss. It will be.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing a cross-sectional structure of an RH furnace according to this embodiment, FIGS. 2 and 3 are exploded perspective views showing a simplified supporting structure of a hearth roller, and FIG. 2 is a hearth roller. 3 shows the support structure of the drive side end portion in FIG. 3, while FIG. 3 shows the support structure of the non-drive side end portion.

The RH furnace according to the present embodiment is provided with a furnace body 1 made of a heat insulating material having a predetermined thickness, and a processing case which is arranged in a furnace space surrounded by the furnace body 1 and which houses a ceramic product. A muffle provided around the transport path through which the object S to be processed passes, for example, a muffle 2 made using a heat-resistant alloy plate such as Inconel or stainless steel, and the inside of the muffle 2. It is provided with a large number of hearth rollers 3 arranged along the horizontal direction that traverses the furnace body 1 and arranged in parallel along the longitudinal direction of the furnace body 1.
At the upper and lower positions of the muffle 2, module heaters 4 each having an electric heater disposed on the inner surface of the furnace of the heat insulating material block are arranged, while the muffle 2 is supplied with an atmosphere supplied from the outside. Gas (or cooling gas) G
A gas introducing pipe 5 for introducing the gas is provided. Further, at this time, a plurality of gas ejection holes (not shown) are formed in parallel on the side surface of the gas introduction pipe 5, and the atmospheric gas G is dispersed in the muffle 2 while passing through each of the gas ejection holes. Is to be introduced in. The hearth rollers 3 are made of a heat-resistant alloy and have a hollow shape or a solid shape. Further, although the module heaters 4 are used in this embodiment, it goes without saying that the electric heaters 27 similar to the conventional example may be used instead of the module heaters 4.

On the other hand, the driving-side and non-driving-side end portions 3a and 3b of each hearth roller 3 have a length protruding to the outside of the furnace body 1, and a heat-resistant alloy plate is provided on each of the outer side surfaces of the muffle 2. A roller receiving tube 6 for housing the respective end portions 3a and 3b of the hearth roller 3 is communicatively connected to the hearth roller 3 after being manufactured as a cylindrical shape. Each of these roller receiving tubes 6 penetrates through the furnace body 1 and then projects to the outside of the furnace.
The drive side end 3a is provided at the outer end of the roller receiving tube 6 accommodating a.
While the cap 7 having the opening 7a through which is inserted is attached by screwing or the like via a sealing material (not shown), the end portions 3b on the non-driving side of each hearth roller 3 are housed. The outer end of the roller receiving tube 6 is closed by a cap 8.

Further, at this time, inside the respective roller receiving tubes 6, supporting parts 9 and 10 for supporting the respective end portions 3a and 3b of the respective hearth rollers 3 in a rotatable and airtightly sealable manner are attached. ing. The support component 9 on one side, that is, the support component 9 for supporting the drive-side end portion 3a of the hearth roller 3 is formed in an annular shape having a predetermined thickness as shown in FIG. The roller-side graphite component 11 externally fitted and fixed to the end portion 3a and the receiving-tube-side graphite component 12 fixed to the inner surface of the roller receiving pipe 6 after being formed into an annular shape having a larger diameter are fitted together. The graphite parts 1 on the roller side and the receiving tube side, respectively
The inside of the roller receiving pipe 6, that is, the inside of the muffle 2 is hermetically sealed depending on the fitting surfaces of the first and the second members. On the other hand, at this time,
As shown in FIG. 3, the support component 10 attached to support the counter-drive side end 3b of the hearth roller 3 is made into a disk shape having a predetermined thickness and then fixed to the drive-side end 3b by interruption. The roller-side graphite component 14 and the receiving-pipe-side graphite component 15 that is fixed to the inner surface of the roller-receiving pipe 6 after being formed into a ring shape having a larger diameter are fitted to each other. The fitting surfaces of the graphite parts 14 and 15 also hermetically seal the inside of the roller receiving pipe 6 and the inside of the muffle 2.

Further, the driving side end portion 3a of each hearth roller 3 to which the roller side graphite component 11 constituting the support component 9 is fixed is inserted through the opening 7a of the cap 7 attached to the outer end of the roller receiving tube 6. In addition, the rotary drive device 13 such as an electric motor is connected to the drive side end 3a. Therefore, these hearth rollers 3 are rotated at an arbitrary transport speed using the rotation drive device 13, and the object S to be processed such as a processing box containing the ceramic product is rotated by the rotation of the hearth rollers 3. It will be transported in the muffle 2 as it moves. Then, the rotating operation of each hearth roller 3 at this time is performed by the supporting parts 9 and 1 attached to each roller receiving tube 6.
It is supported by the combination of each of the roller-side graphite parts 11 and 14 forming 0 and each of the receiving tube-side graphite parts 12 and 15. In the present embodiment, the end portions 3a and 3b of each hearth roller 3 are housed in the roller receiving tubes 6, respectively.
Needless to say, 3b may be collectively stored in a large roller receiving box (not shown) instead of the roller receiving tube 6.

[0015]

As described above, the RH according to the present invention
In the furnace, the use of a muffle makes it possible to precisely control the concentration of the atmospheric gas, and as a result of the precise control of the gas concentration, the temperature distribution in the atmospheric gas introduced into the muffle can be made uniform. Can be realized. Then, even if the peeled matter falls from the inner surface of the furnace body or the like, the fallen peeled matter is received by the muffle, and the characteristics of the object to be treated cannot be adversely affected.

Further, since the structure for conveying the object to be processed is employed by using a large number of hearth rollers, the speed of conveying the object to be processed can be changed by changing the rotation speed of the hearth roller in each predetermined range. This makes it possible to realize the optimum profile for the object to be processed. Further, it is possible to obtain an effect that the heat energy loss can be suppressed to about 20 to 30% as compared with the case of the mesh belt.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a cross-sectional structure of an RH furnace according to this embodiment.

FIG. 2 is an exploded perspective view showing a simplified support structure of a drive-side end portion of a hearth roller.

FIG. 3 is an exploded perspective view showing a simplified supporting structure of an end portion on a side opposite to a driving side of a hearth roller.

FIG. 4 is a schematic cross-sectional view showing a cross-sectional structure of a conventional RH furnace.

[Explanation of symbols]

 2 Muffle 3 Hearth roller 3a Drive end 3b Counter drive end 6 Roller receiving tube 9 Supporting part 10 Supporting part 11 Roller side graphite part 12 Receiving side graphite part 13 Roller side graphite part 14 Receiving side graphite part

Claims (2)

[Claims] 1. A hearth roller provided with a muffle arranged so as to surround a conveyance path of an object to be processed, and a hearth roller arranged across the inside of the muffle, and connected to the outside of each side surface of the muffle so as to communicate therewith. A roller receiving tube for accommodating each end of the hearth roller, and a support component mounted in each roller receiving tube to rotatably and hermetically seal the end of the hearth roller. Roller hearth type heat treatment furnace. 2. The support component is formed by fitting a roller-side graphite component fixed to an end portion of a hearth roller and a receiving tube-side graphite component fixed to an inner surface of a roller receiving pipe. The roller hearth type heat treatment furnace according to claim 1.