JPH05187776A - Batch type rotary retort furnace - Google Patents

Abstract

PURPOSE:To obtain a batch type rotary retort furnace in which stabilization of quality, after a material to be baked is baked, can be easily realized. CONSTITUTION:A batch type rotary retort furnace 1 comprises a core tube 4 of a double structure having an inner tube 2 for containing a material S to be baked and an outer tube 3 concentrically inserted with the tube 2. The tube 2 is formed of a porous material, and a gas supply passage 14 is provided between the tubes 2 and 3. Further, a gas exhaust tube 15 is inserted into the tube 2 for constituting the tube 4 of the furnace 1. The tube 15 is formed of the porous material, or heat resistant metal formed with many gas suction ports at its side face.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a batch type rotary retort furnace used for firing an object to be fired in an atmosphere gas.

[0002]

2. Description of the Related Art Conventionally, a pusher type continuous firing furnace (hereinafter referred to as a pusher furnace) or a batch type rotary retort furnace (hereinafter referred to as a retort furnace) has been used for pre-baking or main-baking a ceramic raw material or a ceramic molded body. ) Is used. That is, the pusher furnace, although not shown, is equipped with a furnace chamber capable of controlling temperature and atmospheric conditions, and a box-shaped casket made of alumina or mullite containing a ceramic raw material to be fired is stored. Each of the stacked base plates is sequentially pushed into the furnace by a pusher mechanism and conveyed, whereby the material to be fired is fired.

As shown in FIG. 2, the retort furnace 30 has a cylindrical retort which is rotatably supported, that is, a furnace core tube 31, and a roller 32 for rotationally driving the furnace core tube 31.
Furnace body 34 provided with heater 33 surrounding furnace core tube 31
It has and. Then, a gas supply pipe 35 and a gas discharge pipe 36 are inserted from both end openings of the furnace core tube 31 so as to be along the central axis of the furnace core tube 31, and both end openings are made of refractory material or heat insulating material. A fired material S such as a ceramic raw material is housed in a furnace core tube 31 which is closed by a heat insulating lid 37 formed by packing and in which an atmospheric gas of a required component circulates.

[0004]

By the way, in the above-mentioned pusher furnace having the conventional structure, each of the saggers is conveyed while being placed at a specific position on the base plate. The ceramic raw material stored in the bowl is baked without any change in the stored state. Therefore, there is a disadvantage that the baking state of the object to be baked differs due to the difference in the storage position in the same casket and the difference in the mounting position between the caskets, resulting in a variation in quality.

On the other hand, in the retort furnace 30, the furnace core tube 3
Since the material to be fired S is driven to rotate together with 1, the difference in firing state unlike in the pusher furnace does not occur. However, since the atmospheric gas to be circulated in the furnace core tube 31 is supplied only from the furnace inner opening 35a of the gas supply pipe 35, and is discharged only from the furnace inner opening 36a of the gas discharge pipe 36. The flow of the atmospheric gas circulating in the furnace core tube 31 is biased only in the furnace length direction, and the atmosphere gas in the furnace core tube 31 cannot be properly controlled. There is an inconvenience that variations in quality occur in the material S to be fired such as ceramic raw materials.

The present invention was devised in view of such inconvenience, and an object thereof is to provide a retort furnace which can easily realize stabilization of the quality of the material to be fired after firing.

[0007]

In order to achieve such an object, a retort furnace according to the present invention has an inner tube for accommodating a material to be fired and an outer tube in which the inner tube is concentrically inserted. A furnace core tube having a double structure consisting of, the inner tube is formed by using a porous material, and a gas supply path is provided between the inner tube and the outer tube. It is a feature. Furthermore, a gas discharge pipe is inserted in the inner pipe that constitutes the furnace core pipe of the retort furnace, and the gas discharge pipe is made of a porous material, or, alternatively, a large number of gas discharge pipes are provided on its side surface. It is characterized in that it is made of a refractory metal in which a gas inlet is formed.

[0008]

According to the above construction, the inner tube forming the furnace core tube is formed by using the porous material, and the gas supply path is provided between the inner tube and the outer tube into which the inner tube is inserted. Therefore, the atmospheric gas supplied through this gas supply path will flow from the entire peripheral surface toward the inside of the inner pipe containing the material to be fired, and the atmospheric gas flowing into this inner pipe Will flow rapidly and spread evenly not only in the furnace length direction but also in the radial direction of the inner pipe. Further, the atmospheric gas that has spread and spread throughout the inner pipe is discharged to the outside of the furnace through the gas discharge pipe, but this gas discharge pipe is made of a porous material, or there are many gas inlets on the side surface. Since it is formed, the atmospheric gas is not evenly biased, and is uniformly discharged into the gas discharge pipe after being discharged.

[0009]

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

FIG. 1 is a sectional view showing a schematic structure of a retort furnace according to this embodiment. Reference numeral 1 in this figure is a retort furnace.

The retort furnace 1 is a firing furnace used when firing a material S to be fired, such as a ceramic raw material or a ceramic compact, in an atmosphere gas, and is a cylindrical inner tube for containing the material S to be fired. 2 and a furnace core tube 4 having a double structure composed of the same cylindrical outer tube 3 into which the inner tube 2 is inserted concentrically, and the outer portion of the central portion along the longitudinal direction of the furnace core tube 4 is provided. The furnace body 6 is provided with a heater 5 that surrounds and heats the periphery.

The inner tube 2 constituting the furnace core tube 4 is formed of a porous ceramic material having excellent heat resistance, that is, a ceramic material such as alumina having a high porosity. The outer tube 3 is formed of a ceramic material that is dense and has a low porosity. The openings at both ends of the outer tube 3 are drawn out to the outside of the furnace and are connected by the end fittings 7. Further, both ends outside the furnace along the longitudinal direction of the furnace core tube 4 are rotatably supported by rollers 8 supported by a furnace body 6, and one roller 8
A drive motor 9 for rotationally driving the furnace core tube 4 at a predetermined speed is connected to.

Further, both end openings of the inner tube 2 accommodating the material to be fired S are closed by a heat insulating lid 10 formed by filling a refractory material or a heat insulating material, while connecting the inner tube 2 and the outer tube 3 to each other. The respective openings of the end fittings 7 constituting the furnace core tube 4 are also closed by end covers 11a and 11b. The heat insulating lid 10 and the end lids 11a,
Each of 11b stores the ceramic raw material or the like as the material to be fired S in the inner tube 2 and is packed,
Of course, it may be attached.

A gas supply pipe 12 for supplying atmospheric gas is connected to the center position of the one end lid 11a through a rotary joint 13 called a rotary joint. Is connected to a gas supply passage 14 provided between the inner tube 2 and the outer tube 3 forming the furnace core tube 4 after penetrating the end lid 11a and the end fitting 7 respectively. . Therefore, the gas supply pipe 12
The atmospheric gas supplied through the gas flows into the gas supply passage 14 and is preheated by the heater 5 via the outer pipe 3 while flowing in the gas supply passage 14.

Since the inner tube 2 constituting the furnace core tube 4 is made of a porous material, the gas supply passage 1
The atmospheric gas that has been preheated by flowing in 4 passes through the wall of the inner pipe 2 and then flows into the inner pipe 2 from its entire peripheral surface. as a result,
The atmospheric gas flowing into the inner pipe 2 containing the material to be fired S no longer flows in a biased state only along the furnace length direction, and the atmospheric gas flowing into the inner pipe 2 is entirely in the inner pipe 2. It will spread rapidly over the course of time.

Furthermore, a gas discharge pipe 15 for discharging atmospheric gas is provided on the center position of the other end lid 11b via a rotary joint 16 called a rotary joint. 15 is an end cover 11
After passing through b, it is inserted along the central axis of the inner tube 3 that constitutes the furnace core tube 4. The gas discharge pipe 15 is formed of the same porous material as the inner pipe 3, that is, a porous ceramic material. In addition,
The furnace temperature in the furnace core tube 4 is, for example, 1000 ° C.
The gas discharge pipe 15 may be made of a heat-resistant metal such as Inconel when the temperature is low as described below. In such a case, the gas discharge pipe 1 made of a heat-resistant metal is used.
A large number of gas inlets (not shown) may be formed on the side surface of 5.

Therefore, the atmospheric gas supplied from the gas supply passage 14 and flowing and spread throughout the inner tube 2 of the furnace core tube 4 is discharged to the outside of the furnace through the gas discharge tube 15.
At this time, since the gas discharge pipe 15 is made of a porous material or has a large number of gas inlets formed on its side surface, the atmospheric gas is not biased in the inner pipe 2. After flowing evenly into the gas exhaust pipe 15, the gas is exhausted through the gas exhaust pipe 15.

In the figure, reference numeral 17 is a pin support tool for swingably supporting the furnace body 6, and 18 is attached to each end of the furnace body 6 for adjusting the inclination of the furnace body 6 and positioning and supporting it. Is a screw jack, and 19 is a sealing material such as a silicone packing used for hermetically sealing the respective parts in contact with each other. That is, the pin support tool 16 and the screw jack 18 facilitate the inflow and outflow of the ceramic raw material into the inner tube 2 by inclining the furnace core tube 4 together with the furnace body 6 at an arbitrary predetermined angle. It is provided to make the stored state of the stored ceramic raw materials uniform,
Further, the sealing material 19 is for securing the pressure inside the furnace core tube 4 in which the atmosphere gas circulates. Further, reference numeral 20 in the drawing denotes a cam and 21 denotes a spring, which are arranged so that only the furnace core tube 4 can be swung along the furnace length direction of the furnace body 6.

[0019]

As described above, according to the retort furnace of the present invention, the atmospheric gas in the inner tube containing the material to be fired does not flow only in the furnace length direction, and the tube of this inner tube does not flow. The atmospheric gas that has passed through the wall and flowed into the inside thereof quickly flows and spreads uniformly over the entire area of the inner pipe. Therefore, as a result of being able to appropriately control the atmospheric gas in the furnace core tube, it is possible to obtain the effect that the quality of the material to be fired after firing can be easily stabilized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic structure of a retort furnace according to the present embodiment.

FIG. 2 is a sectional view showing a schematic structure of a retort furnace according to a conventional example.

[Explanation of reference symbols] 1 retort furnace (batch type rotary retort furnace) 2 inner tube 3 outer tube 4 furnace core tube 14 gas supply path 15 gas discharge tube S fired object

Claims (3)

[Claims] 1. An inner tube (2) for accommodating an object to be fired (S)
And a furnace core tube (4) having a double structure composed of an inner tube (2) and an outer tube (3) inserted concentrically, the inner tube (2) is made of a porous material. And a gas supply passage (14) provided between the inner pipe (2) and the outer pipe (3). 2. A gas exhaust pipe (15) is inserted into the inner pipe (2) constituting the furnace core pipe (4), and the gas exhaust pipe (15) is formed by using a porous material. The batch-type rotary retort furnace according to claim 1, wherein 3. A gas exhaust pipe (15) is inserted into the inner pipe (2) constituting the furnace core pipe (4), and the gas exhaust pipe (15) is formed by using a refractory metal, The batch type rotary retort furnace according to claim 1, wherein a plurality of gas inlets are formed on a side surface of the batch type rotary retort furnace.