JP2002286372A - Heat treat furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a gas feed amount per one gas feed pipe as an injection speed through a gas injection port and a whole gas feed amount are maintained. SOLUTION: Two or more gas feed pipes are divided each into two or more regions in a direction of a length. A gas injection port is formed in either of the regions. The gas feed pipes each having a gas injection port formed in the different region make one set which are disposed in a furnace. The gas injection region by one set of the gas feed pipes covers the whole height region of a substance to be heat-treated situated at least on a furnace floor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment furnace used for heat-treating an unheated object such as a ceramic element in a predetermined atmosphere, and more particularly to a structure of a gas supply pipe.

[0002]

2. Description of the Related Art In the process of manufacturing ceramic electronic components, when a heat-treated object such as an unfired ceramic element is fired, usually, a batch-type heat treatment furnace or a tunnel-type heat treatment furnace is used. In order to control the atmosphere around the object to be heat-treated to a predetermined condition, heat treatment is performed while supplying an atmosphere gas into the furnace in order to control the atmosphere around the object to be heat-treated in multiple stages.

FIGS. 5 (a) and 5 (b) are views showing a sectional structure of a batch type heat treatment furnace 1 of a hearth rotating type and a state in which an atmosphere gas is supplied into the furnace. Area view,
(B) is a cross-sectional view. The batch type heat treatment furnace 1 includes a furnace body 2, a hearth 3 provided at a lower portion of the furnace body, two heaters 4 and 4 fixed inside the furnace body 2, and a substantially vertical direction from an upper part of the furnace body 2. Gas supply pipes 5, 5 inserted into
And a gas exhaust pipe 6 also inserted in a substantially vertical direction from the upper part of the furnace main body 2. On the rotating bed 3 a of the hearth 3, a plurality of boxes 7 on which the objects to be heat-treated are placed are stacked. I have.
Note that a heat insulating material 8 is attached around the firing space inside the furnace main body 2.

[0006] As shown in FIG. 6, the gas supply pipe 5 is provided with a plurality of gas outlets 9 over substantially the entire length thereof along the length of the gas supply pipe 5. It is installed in the furnace to face. Normally, a plurality of gas supply pipes 5 are provided around the box 7, and an atmosphere gas is supplied from the periphery toward the box 7 as shown by arrows in FIGS. 5 (a) and 5 (b). ing.

That is, when an atmospheric gas is supplied from a gas supply device (not shown) to the gas supply pipe 5 at a predetermined pressure, the atmospheric gas is supplied from the gas outlet 9 at a speed reaching several m / s at room temperature. It is gushing. When this atmospheric gas enters into the distant space of the furnace or the gap between the stacked boxes 7, the unevenness of the atmosphere is prevented, and the heat treatment is performed in a uniform atmosphere. The rotation of the rotary bed 3a of the hearth 3 also changes the mutual position of the object to be heat-treated and the gas supply pipe 5, thereby suppressing the occurrence of a bias in the state of jetting of the atmospheric gas to the object to be heat-treated.

[0006]

In the conventional heat treatment furnace 1,
In order to obtain a jet gas flow rate of about several m / s from the gas outlet 9 of the gas supply pipe 5, 20 to 5
It is necessary to provide as much as 0 LM gas. When the amount of gas supplied to the gas supply pipe 5 is large, the temperature near the opening 5a of the gas supply pipe 5 into which the atmospheric gas flows decreases, and the temperature difference between the gas supply pipe 5 and the tip 5b of the gas supply pipe 5 increases. Due to the difference, the gas supply pipe 5 was easily broken.

During firing, at least one gas supply pipe 5
When the gas is broken, the atmospheric gas is released from the broken portion, so that the pressure of the other gas supply pipe 5 is reduced, and the atmospheric gas is not ejected from the gas ejection port 9. As a result, due to insufficient supply of the atmosphere gas into the inside of the housing 7, there is a problem that the properties of the heat-treated object after firing may be defective or the variation may be large.

Further, as described above, the conventional gas supply pipe 5 is easily broken, and its life is about half a year. Frequent replacement of the gas supply pipe 5 has caused an increase in firing cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat treatment furnace in which the life of a gas supply pipe is improved, characteristic defects and variations due to firing are reduced, and firing costs are further reduced.

[0010]

A heat treatment furnace according to the present invention comprises: a furnace main body having a heat treatment space therein; a hearth provided at a lower portion of the furnace main body; a heater provided inside the furnace main body; 2 inserted substantially vertically into the furnace body
A plurality of gas supply pipes, and a gas exhaust pipe also inserted into the furnace main body, wherein the two or more gas supply pipes each have substantially two or more lengthwise regions substantially in the entire length direction. And a gas ejection port is formed in any one of the regions. The gas ejection region formed by the two or more gas supply pipes has at least the entire height of the heat treatment target disposed on the hearth. It is characterized by including a region.

The two or more gas supply pipes are provided in a furnace as a set of gas supply pipes each having a gas ejection port formed in each of the divided areas, and are provided by the set of gas supply pipes. It is preferable that the gas ejection region includes at least the entire height region of the heat treatment target disposed on the hearth.

For example, each of the two gas supply pipes is divided into two upper and lower areas in the longitudinal direction, and a gas ejection port is formed in each of the upper and lower areas, and the two gas supply pipes are formed as one set. By using the gas supply pipe, the gas supply rate per one gas supply pipe can be reduced while maintaining the gas discharge speed and the entire gas supply rate as compared with a single gas supply pipe having a gas discharge port formed over substantially the entire length. It can be reduced to 1/2.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. However, the same components as those of the conventional batch type heat treatment furnace 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIGS. 1A and 1B are views showing a sectional structure of a batch type heat treatment furnace 11 of a hearth rotating type and a state in which atmospheric gas is supplied into the furnace, and FIG. Area view,
(B) is a cross-sectional view. The batch type heat treatment furnace 11 includes a furnace body 2, a hearth 3 provided at a lower portion of the furnace body, and a furnace body 2.
Two heaters 4 fixed inside, and four gas supply pipes 15, 1 inserted substantially vertically from the upper part of the furnace body 2
6, 15 and 16 and a gas exhaust pipe 6 also inserted in a substantially vertical direction from the upper part of the furnace main body 2. A box 7 on which a heat treatment target is placed is mounted on a rotating floor 3 a of the hearth 3. Stacked in multiple layers.

The gas supply pipes 15 and 16 are made of high-purity dense alumina. One end of each of the gas supply pipes 15 and 16 is opened as an atmosphere gas supply port 15a or 16a, and the other end of the gas supply pipe 15 or 16b is closed. Having a cylindrical structure. Outer diameter of gas supply pipes 15 and 16 is 20 mm, inner diameter is 15 m
m, length is 75 mm.

The gas supply pipe 15 and the gas supply pipe 16 differ from each other in the region where the gas ejection port 9 is formed in the cylindrical portion.
That is, the gas supply pipe 15 has the gas ejection port 9 formed in the lower half part divided into two regions in the length direction, and the gas supply pipe 16 has the gas ejection port 9 formed in the upper half part. The diameter of the gas outlet 9 is 0.5 mm and the pitch is 1 mm.

The gas supply pipe 15 and the gas supply pipe 16
Each one is a set, and a total of two sets of four
Are disposed in the furnace to face each other. As a result, as shown by arrows in FIGS. 1A and 1B, the ambient gas is supplied from the periphery of the box 7 to the entire height region of the box 7.

That is, in the batch type heat treatment furnace 11, the gas ejection region of one gas supply pipe 5 used in the conventional batch type heat treatment furnace 1 is divided into upper and lower parts, and two gas supply pipes 15, 16 are provided respectively. The gas ejection regions are formed separately. As a result, the gas ejection area per gas supply pipes 15 and 16 becomes one half that of the conventional example, and the conventional gas ejection is performed at a gas flow rate of one half of the conventional one while maintaining the entire gas supply amount. You can get speed.

According to the above embodiment, the gas supply pipes 15, 1
6. By reducing the gas flow rate per pipe to half, the life of the gas supply pipe was dramatically improved from about half a year to 1.5 to 2 years.

In the above embodiment, the material of the gas supply pipes 15 and 16 is not limited to high-purity dense alumina.
If the material can withstand the temperature and atmosphere of the heat treatment furnace, Si
Other ceramic materials, such as C, or metallic materials, such as Inconel, can be used, but they are particularly effective for ceramic gas supply tubes that are easily broken due to a difference in thermal expansion.

In the above embodiment, the gas jet 9
Is a circle having a diameter of 0.5 mm and a pitch of 1 mm.
The shape and pitch of the gas ejection port can be arbitrarily selected as long as the atmosphere around the heat treatment target can be controlled under predetermined conditions. For example, the hole shape of the gas ejection port may be a slit shape or an elliptical shape.

Further, in the above embodiment, one of the conventional examples is used.
The gas ejection area formed in the gas supply pipe 5
Although the gas supply region is provided in each of the two gas supply pipes 15 and 16 by dividing, the gas supply region may be divided into a larger number of regions and a larger number of gas supply regions may be provided. For example, in another embodiment shown in FIG. 3, the gas ejection region formed in one gas supply pipe 5 of the conventional example is divided into three upper and lower parts, and three gas supply pipes 17, 18, and 19 are provided. Each gas ejection area is provided, and these three gas supply pipes 17, 18, and 19 are used as one set. According to this, the gas supply pipe 17,
18, 19, the gas flow rate per pipe is reduced to 1/3 of the gas flow rate per conventional gas supply pipe 5.

Further, the present invention is not limited to the batch type firing furnace of the above embodiment, but may be used for a continuous type furnace as shown in FIG.

[0024]

According to the present invention, two or more gas supply pipes are divided into two or more regions in the longitudinal direction, and a gas ejection port is formed only in any one of the two regions. By arranging a plurality of gas supply pipes each having a gas ejection port formed in the furnace as a set, a gas supply pipe is formed in almost the entire area in the longitudinal direction, compared with a conventional gas supply pipe having a gas ejection port formed in almost the entire area. Thus, the gas supply rate per gas supply pipe can be reduced while maintaining the gas ejection speed from the gas ejection port and the entire gas flow rate.

As a result, it is possible to improve the life of the gas supply pipe, reduce the characteristic failure and variation in firing, and further reduce the firing cost.

[Brief description of the drawings]

FIG. 1 shows a heat treatment furnace according to one embodiment of the present invention, wherein (a) is a longitudinal sectional view and (b) is a transverse sectional view.

FIG. 2 is a perspective view showing a gas supply pipe used in the heat treatment furnace of FIG.

FIG. 3 is a perspective view showing a gas supply pipe according to another embodiment of the present invention.

FIG. 4 is a schematic view showing a heat treatment furnace according to another embodiment of the present invention.

5A and 5B show a conventional heat treatment furnace, wherein FIG. 5A is a longitudinal sectional view and FIG. 5B is a transverse sectional view.

FIG. 6 is a perspective view showing a gas supply pipe used in the heat treatment furnace of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Batch type heat treatment furnace 2 Furnace main body 3 Hearth 4 Heater 15, 16, 17, 18, 19 Gas supply pipe 6 Gas exhaust pipe 7 Box 9 Gas ejection port

Claims (2)

[Claims] 1. A furnace body having a heat treatment space therein, a hearth provided at a lower portion of the furnace body, a heater provided inside the furnace body, and inserted into the furnace body in a substantially vertical direction. The gas supply pipe includes two or more gas supply pipes, and a gas exhaust pipe also inserted into the furnace body. The two or more gas supply pipes each have substantially the entire area in the length direction. A gas ejection port is formed in any one of the above areas, and the gas ejection area formed by the two or more gas supply pipes has at least a total height of the heat treatment target disposed on the hearth. A heat treatment furnace comprising a heat treatment zone. 2. The gas supply pipe, wherein the two or more gas supply pipes are provided as a set of gas supply pipes each having a gas ejection port formed in each of the divided areas, and the gas supply pipes of the set are provided. The heat treatment furnace according to claim 1, wherein the gas ejection region by the tube includes at least a whole height region of the heat treatment target disposed on the hearth.