KR20140088352A - A continuous type furnace and a control method of the same - Google Patents

Abstract

The present invention relates to a continuous type furnace and a controlling method thereof particularly whereby an atmosphere inside the furnace can be maintained to be constant. The continuous type furnace includes: an inlet and an outlet; a chamber including a plurality of heating zones arranged in the lengthwise direction of the furnace; a transferring means which transfers an object to be treated, which is inserted into the inlet of the chamber; moreover, a substitution zone located in at least one from an upper stream of the furnace, a lower stream of the furnace, or the heating zone; and a first buffer zone and a second buffer zone which are located on an upper stream and a lower stream of the substitution zone, respectively. According to the present invention, the continuous type furnace can prevent the atmosphere inside the furnace from being affected by gas flowing in from the inlet, the outlet, or an adjacent heating zone having a different atmosphere.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous type heat treatment furnace,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous heat treatment furnace and a control method thereof, and more particularly, to a continuous heat treatment furnace capable of maintaining a constant atmosphere in a furnace and a control method thereof.

The heat treatment furnace can be divided into a non-continuous heat treatment furnace (Batch Type Furnace) and a continuous heat treatment furnace (Continuous Type Furnace). The non-continuous heat treatment furnace is a method in which products are loaded on a cycle-by-cycle basis and refers to a method in which the product stays in the furnace until the heat treatment is completely completed.

The continuous heat treatment furnace is advantageous in mass production compared to the non-continuous heat treatment furnace in that the product is directly heat treated according to the predetermined conditions by designating the heat treatment condition of the product, that is, the temperature profile and the oxygen concentration.

In the continuous heat treatment furnace, there are a direct heating type in which the combustion flame directly contacts with the heating method of the object to be heated and an indirect heating type in which the combustion flame does not directly touch. In the indirect heating type continuous heat treatment furnace, there is a muffle type which indirectly heats the object to be heated by heating the tunnel type heating chamber. Although the direct heating type has an advantage of low heat loss, it can not heat the object to be cleaned constantly and can contaminate and damage the object to be cleaned. Therefore, in a process of producing electronic parts such as a multilayer ceramic capacitor and a chip inductor, use. A mesh belt, a roller, a pusher, or the like is used as a means for conveying the object to be heated in the continuous heat treatment furnace.

The continuous heat treatment furnace is equipped with a heating element, an air supply device and an exhaust device to set the internal heating sections of the heat treatment furnace to a desired temperature and atmosphere.

The heating element is for setting the inside of the heat treatment furnace to a desired temperature. A plurality of heating elements are gathered to form a prebaking (binder removal) section, a firing section, a reformation section, and a slow cooling section.

The air supply unit maintains the internal pressure of the heat treatment furnace to be a positive pressure, and serves to supply a mixed gas at a predetermined ratio to produce a desired atmosphere.

The exhaust device serves to suck the gas generated from the object to be treated and to discharge it to the outside. The exhaust device may include an exhaust pipe connected to the gas suction member and the gas suction member, and an exhaust port for discharging the sucked gas to the outside. In particular, the gases generated from the pollutants in the binder removal process must be removed since they can react with oxygen in the heat treatment furnace to form an intense strong reducing atmosphere.

U.S. Patent No. 4,397,451 U.S. Patent No. 4,586,898 U.S. Patent No. 4,932,864

Although the above-described continuous heat treatment furnace has an advantage of being suitable for mass production, there is a problem that it is very difficult to independently set the temperature and atmosphere of the heating sections because the heating sections are continuously arranged. Particularly, there is a problem in that when the external air is introduced into the heat treatment furnace during the process of injecting and discharging the object to the inlet and the outlet, the atmosphere in the furnace may be influenced.

In the case of an electronic component such as a capacitor or an inductor using nickel or copper internal electrodes, firing is performed in a reducing atmosphere to prevent oxidation of the internal electrode, and heat treatment is performed again in an oxidizing atmosphere to reoxidize the ceramic. Therefore, in the case of simultaneous sintering and reoxidation in one continuous heat treatment furnace, it is necessary to isolate between the firing section and the reification section. When the reducing atmosphere gas in the firing section flows into the reoxidizing zone, the ceramic is not fully reoxidized and the strength becomes very weak, and the electrical characteristics are also adversely affected. Also, when oxygen in the reoxidization zone flows into the firing zone, the internal electrode is oxidized and expanded, causing cracks in the ceramic, and the electrical resistance of the internal electrode may increase.

U.S. Patent No. 4,397,451 discloses a continuous heat treatment furnace in which a heating zone in a reducing atmosphere and a heating zone in an oxidizing atmosphere are continuously arranged. In this patent, a purge chamber is provided between the heating section of the reducing atmosphere on the upstream side and the heating section of the oxidizing atmosphere on the downstream side. On the upstream side and the downstream side of the purge chamber, a pair of doors for isolating the purge chamber are provided.

However, it is difficult to completely separate the heating zones by installing the doors on the upstream side and the downstream side of the purge chamber as described in the patent, so that the gas in the upstream heating zone flows into the heating zone on the downstream side in the process of opening and closing the door. Particularly, when the heat treatment time is short and the number of door opening / closing per unit time is large, the amount of the introduced gas increases. In addition, the above-mentioned patent places the gas on the upstream side of the purge chamber into the purge chamber, so that the reducing gas has to flow into the downstream side heating section.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in order to solve the above problems of the continuous heat treatment furnace, and it is an object of the present invention to provide a heat exchange apparatus, And it is an object of the present invention to provide a continuous type heat treatment furnace capable of shutting off influenced by an atmosphere of another heating section.

According to an aspect of the present invention, there is provided a continuous heat treatment furnace including a chamber including an inlet and an outlet, a plurality of heating sections arranged along a longitudinal direction of the heat treatment furnace, And a conveying means for conveying the sheet toward the exit.

A first buffer section disposed on the upstream side and a downstream side of the replacement section, and a second buffer section disposed on the upstream side and the downstream side of the replacement section, 2 buffer sections.

A first door, which is disposed on the upstream side and the downstream side of the first buffer section and is movable between an open position where the object to be processed can pass through and a closed position where the first buffer section can be isolated, And a second door that is disposed on the upstream side and the downstream side of the second buffer section and is movable between an open position through which the object to be processed can pass and a closed position where the second buffer section can be isolated A first buffer section purge gas supply means for supplying a purge gas to the first buffer section and a second buffer section purge gas supply means for supplying a purge gas to the second buffer section, A purge gas purge gas supply means for purge the purge gas into the purge gas;

The continuous heat treatment furnace may further include a first buffer section sensor installed in the first buffer section so as to detect the object to be processed. When the object to be processed is detected by the first buffer section sensor, One door may be closed, and the second door may be opened after a predetermined time. The apparatus may further include a second buffer section sensor installed in the second buffer section so as to detect the object to be processed. When the object to be processed is detected in the second buffer section sensor, the third door is closed, The fourth door may be configured to be opened after a predetermined time.

Wherein at least one of the replacing means is provided between the heating sections and further includes an air supply device for supplying gas to the heating section and an exhaust device for exhausting the gas in the heating section, Is preferably arranged such that the gas supplied from the air supply device flows in a direction away from the replacing means provided between the heating means and is discharged to the exhausting device.

Preferably, the conveying means includes a plurality of rollers, and the plurality of rollers are divided into a plurality of groups in which rotational speeds are individually controlled.

According to another aspect of the present invention, there is provided a control method of the continuous heat treatment furnace, comprising the steps of: a) opening the first door and transferring the object to be processed into the first buffer section; b) Closing the door and opening the second door; c) transferring the object to be processed into the replacement section and closing the second door; d) closing the first buffer section, the second buffer section, Supplying purge gas to the buffer section and the replacement section, e) removing purge gas in the replacement section, f) supplying purge gas to the replacement section, g) opening the third door , H) transferring the object to be processed into the second buffer section, h) closing the third door and opening the fourth door, i) opening the object to be processed in the second buffer section To the outside, and closing the fourth door, the control method of the continuous heat treatment furnace It is a ball.

The heat treatment furnace according to the present invention has an effect of preventing the atmosphere inside the heat treatment furnace from being affected by the gas introduced from the inlet, the outlet, or the adjacent heating section having different atmospheres. Therefore, there is an advantage that heat treatment in the reducing atmosphere and heat treatment in the oxidizing atmosphere can be performed simultaneously through one heat treatment furnace.

1 is a schematic view of an embodiment of a continuous heat treatment furnace according to the present invention.
Fig. 2 is a view showing a part of the continuous heat treatment furnace shown in Fig. 1. Fig.
3 is a view for explaining the action of the continuous heat treatment furnace shown in Fig.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. To fully disclose the scope of the invention, and the invention is only defined by the claims.

1 is a schematic view of an embodiment of a continuous heat treatment furnace according to the present invention.

Referring to FIG. 1, an embodiment of a continuous heat treatment furnace according to the present invention includes a chamber 10 and a conveying means 20. The chamber 10 includes a tunnel made of the refractory 11 in which the heating element 12 is installed and a metal case 13 for sealing and sealing the tunnel.

The transfer means 20 transfers the object W in the direction of the outlet 16 from the inlet 15 of the chamber 10. The conveying means 20 may include a motor, a pulley, a belt, or the like for transmitting a driving force to the roller 21 and the roller 21. The conveying means 20 may include a plurality of rollers 21 composed of a plurality of rollers 21 and individually adjustable in speed.

The chamber 10 is provided with a plurality of heating sections 50 having different temperatures and atmospheres. Each of the heating sections 50 may include a plurality of heating elements and each of the heating sections 50 is provided with an air supply device 30 and an exhaust device 40 for controlling the atmosphere of the heating section 50 do. The firing and re-oxidizing profile of the ceramic capacitor using the nickel internal electrode will be described below. The heating section 50 mainly includes a binder removal section 50a, a firing section 50b, a reformation section 50c, (50d), and the like. Each section may be subdivided according to the heating rate or the oxygen concentration. Generally, in the firing section 50b, gas mixed with nitrogen and hydrogen at an appropriate ratio is introduced through the air supply device 30, and in the re-oxidation section 50c, gas mixed with nitrogen and oxygen at an appropriate ratio is introduced . The gas introduced through the air supply device (30) is removed through the exhaust device (40). Hereinafter, the firing section 50b and the reformation section 50c will be described as examples of heating sections in different atmospheres.

As shown in Fig. 1, a replacement section 60 is disposed on the upstream side of the inlet 15, on the downstream side of the outlet 16, and between the firing section 50b and the reification section 50c. The replacement section 60a provided on the upstream side of the inlet 15 serves to prevent the outside air from flowing into the inlet 15 of the chamber 10 when the article W is introduced. The replacement section 60c provided on the downstream side of the outlet 16 serves to prevent the outside air from flowing into the outlet 16 of the chamber 10 when the object W is discharged. The replacement section 60b between the firing section 50b and the reformation section 50c is a state in which the reducing atmosphere gas of the firing section 50b flows into the reformation section 50c, Thereby preventing the gas from flowing into the firing section 50b.

Since the three replacement sections 60 have the same structure, the following description will be made on the basis of the replacement section 60b provided between the firing section 50b and the reification section 50c.

Referring to FIGS. 1 and 2, a first buffer section 70b is disposed between the replacement section 60b and the firing section 50b. And a second buffer section 80b is disposed between the replacement section 60b and the reuse section 50c.

Since the first buffer section 70b and the second buffer section 80b have the same structure, only the configuration of the first buffer section 70b will be described. The first buffer section 70b includes a first door 71b disposed at the upstream side of the first buffer section 70b and a second door 72b disposed at the downstream side of the first buffer section 70b And a fourth door in the second buffer period). The first door 71b and the second door 72b are opened and closed by the conveying means 20 through the heating zones 50 inside the chamber 10, Position to isolate the first buffer section 70b from the first buffer section 70b. In Figures 1 and 2 all doors are shown as being in the closed position. It is preferable that the first door 71b and the second door 72b are configured to be in close contact with the walls of the firing section 50b and the replacement section 60b at the closed position and away from the open position. The rising and falling of the first door 71b and the second door 72b in this manner can be realized by an appropriate mechanism already known.

The chamber 10 is provided with a first buffer section purge gas supply means 74b for supplying a purge gas to the first buffer section 70b and a second buffer section 74b for supplying purge gas to the second buffer section 80b. A purge gas supply means 84b is provided. As the purge gas, nitrogen gas may be used.

The replacement section 60b may be sealed by the second door 72b of the first buffer section 70b and the third door 81b of the second buffer section 80b. The replacement section 60b is provided with a vacuum means 63b capable of removing gas in the replacement section 60b and a replacement section purge gas supply means 62b capable of supplying purge gas into the replacement section 60b.

Hereinafter, the operation of the first buffer section 70b, the second buffer section 80b and the replacement section 60b will be described with reference to FIG.

3 (a), when the object to be processed w reaches the end of the firing section 50b, the first door 71b is opened and the object W is moved to the first buffer section 70b, the first door 71b is closed, as shown in Fig. 3 (b). A first buffer section sensor (not shown) is provided between the first door 71b and the second door 72b so that when the object to be processed w is detected to enter the first buffer section 70b, (71b) can be closed.

Next, when the workpiece w reaches the end of the first buffer section 70b, the second door 72b is opened as shown in Fig. 3 (c). The second door 72b may be opened after a predetermined time has elapsed according to the length and the conveying speed of the first buffer section 70b after the first door 71b is opened.

3 (d), the second door 72b is closed and the first buffer section 70b and the second buffer section 70b are closed as shown in FIG. 3 (d) The purge gas is supplied to the replacement section 80b and the replacement section 60b. Then, as shown in FIG. 3 (e), the gas inside the replacement section 60b is discharged by the vacuum means. It is possible to determine the closing time of the second door 72b by providing a replacement section sensor that confirms that the object W reaches the replacement section 60b.

The second door 72b and the third door 81b are moved in the direction of the displacement section 60b by the pressure difference between the first buffer section 70b and the second buffer section 80b and the replacement section 60b, So as to be in close contact with each other. Therefore, the second door 72b and the third door 81b are provided with the mechanical adhesion force, the first buffer section 70b, and the adhesion due to the pressure difference between the second buffer section 80b and the replacement section 60b, Is applied. Therefore, the replacement interval 60b can be almost completely isolated from the first buffer interval 70b and the second buffer interval 80b. The purge gas is supplied to the first buffer section 70b and the second buffer section 80b and the replacement section 60b is isolated from the firing section 50b or the reuse section 50c by the double door. So that the gases in the firing section 50b and the reformation section 50c are prevented from flowing into the replacement section 60b by the vacuum pressure.

If the pressure of the purge gas supplied to the first buffer section 70b and the second buffer section 80b is higher than the pressure of the firing section 50b or the reoxygenation section 50c, Since the fourth door 82b is pressed in the direction of the firing section 50b and the rearmost section 50c respectively, the adhesion between the first door 71b and the fourth door 82b can be further improved.

Next, as shown in Fig. 3 (f), the purge gas is supplied again to the replacement section 60b. The third door 81b is not opened due to the pressure difference between the first buffer section 70b and the second buffer section 80b and the replacement section 60b unless the pressure of the replacement section 60b is increased.

3 (g), when the third door 81b is opened and the object W enters into the second buffer section 80b, as shown in FIG. 3 (h) Likewise, the third door 81b is closed. The second buffer section 80b may be provided with a second buffer section sensor capable of detecting the object w. When the to-be-processed w reaches the end of the second buffer section 80b, as shown in Fig. 3 (i), the fourth door 82b is opened and the to-be- Section 50c. Finally, as shown in Fig. 3 (k), the fourth door 82b is closed.

When the next object to be processed w reaches the end of the firing section 50b, the above process is repeated.

The transfer speed of the object to be processed w in the vicinity of the first buffer section 70b, the replacement section 60b and the second buffer section 80b is set to the firing period 50b and the reformation section 50c. For example, the section A and the section C in FIG. 2 can reduce the conveying speed and speed up the conveying speed of the section B. In section B, the speed of each section may be different. For example, the feed rate in the replacement interval 60b may be faster than the feed rate in the first buffer interval 70b and the second buffer interval 80b. The object to be processed w located at the end of the section A at the time when the object w to travel in the section A and the section C moves by the length of the object w is the first buffer section 70b, The object to be processed w can be continuously injected by regulating the speed of the section B so as to be discharged to the beginning of the section C through the second buffer section 60b and the second buffer section 80b.

Hereinafter, the air supply device 30 and the air exhaust device 40 for controlling the atmosphere of the heating zone 50 will be described. 1 and 2, in this embodiment, an air supply device 30 and an air exhaust device 40 are provided in each heating section 50. In this embodiment, The air supply device 30 may include bombs, a flow meter, a gas pipe, a wetter, a supply box 31 installed in the chamber 10, and the like, in which nitrogen, hydrogen, and oxygen gas are respectively stored. The air supply box 31 is provided with a plurality of through holes or through slots through which gas can be discharged. The exhaust device 40 may include an exhaust box 41 as a gas suction member installed in the chamber 10, an exhaust pipe connected to the exhaust box 41, and an exhaust port connected to the exhaust pipe. The exhaust box 41 is provided with a plurality of through holes or through slots for sucking gas.

The air supply box 31b and the air exhaust box 41b of the firing section 50b flow in the direction in which the reducing atmosphere gas introduced from the air supply box 31b moves away from the replacement section 60b, As shown in Fig. That is, the air supply box 31b is disposed on the downstream side close to the replacement section 60b, and the air exhaust box 41b is disposed on the upstream side far from the replacement section 60b.

The supply box 31c and the exhaust box 41c of the re-oxidation section 50c are arranged so that the oxidizing atmosphere gas flowing in the supply box 31c flows away from the replacement section 60b and is discharged through the exhaust box 41c Respectively. That is, the air supply box 31c is disposed on the upstream side close to the replacement section 60b, and the air exhaust box 41c is disposed on the downstream side far from the replacement section 60b.

By arranging the air supply boxes 31b and 31c and the exhaust boxes 41b and 41c in such a manner that the gas in the firing section 50b and the remainder section 50c flow in a direction away from the replacement section 60b, It is possible to further reduce the possibility that the gases in the firing section 50b and the reformation section 50c are introduced into each other through the replacement section 60b.

While the present invention has been described with reference to the preferred embodiments, it is to be understood that the scope of the invention is limited only by the scope of the appended claims and that those skilled in the art, It is possible to modify the technical idea of the present invention to various forms. Accordingly, such improvements and modifications will fall within the scope of the present invention as long as they are obvious to those skilled in the art.

It is possible to use a roller 21 as the conveying means 20 but it is also possible to use a conveying means 20 for conveying the object w and a pusher for pushing the substrate into the chamber 10 . ≪ / RTI >

When the reoxidization is carried out using a separate heat treatment furnace, the replacement sections 60a and 60c may be provided only on the inlet 15 side and the outlet 16 side of the chamber 10.

10: chamber 15: inlet
16: exit 20: conveying means
21: roller 30: supply device
40: Exhaust device 50: Heating section
50b: firing section 50c: reformation section
60: Substitution section 62: Substitution section Purge gas supply means
63: Vacuum means 70: First buffer section
71: first door 72: second door
74: first buffer section purge gas supply means 80: second buffer section
81: Third door 82: Fourth door
84: second buffer section purge gas supply means

Claims (6)

There is provided a continuous heat treatment furnace including a chamber including an inlet and an outlet, a plurality of heating sections arranged along the longitudinal direction of the heat treatment furnace, and a conveying means for conveying the object to be processed introduced into the inlet of the chamber toward the outlet ,
A replacement section disposed at at least one of an upstream side of the inlet of the chamber, a downstream side of the outlet, and a portion between the heating sections,
A first buffer section and a second buffer section arranged on the upstream side and the downstream side of the replacement section, respectively,
A first door disposed at an upstream side and a downstream side of the first buffer section and capable of moving between an open position through which the object to be processed can pass and a closed position capable of isolating the first buffer section, 2 door,
A third door that is disposed on the upstream side and the downstream side of the second buffer section and is movable between an open position where the object to be processed can pass through and a closed position where the object can be isolated from the second buffer section; 4 doors,
A first buffer section purge gas supply means for supplying purge gas to the first buffer section; a second buffer section purge gas supply means for supplying purge gas to the second buffer section;
A vacuum means for removing gas in the replacement section,
And a replacement section purge gas supply means for supplying purge gas into the replacement section. The method according to claim 1,
Further comprising a first buffer section sensor installed in the first buffer section so as to detect the object to be processed,
Wherein when the object to be processed is detected by the first buffer section sensor, the first door is closed and the second door is opened after a predetermined time. The method according to claim 1,
And a second buffer section sensor provided in the second buffer section so as to detect the object to be processed,
Wherein when the object to be processed is detected by the second buffer section sensor, the third door is closed and the fourth door is opened after a predetermined time. The method according to claim 1,
Wherein at least one of the replacing means is provided between the heating sections,
Further comprising an air supply device for supplying gas to the heating section and an exhaust device for exhausting the gas in the heating section,
Wherein the air supply device and the exhaust device are arranged such that the gas supplied from the air supply device flows in a direction away from the replacing means provided between the heating means and is discharged to the exhaust device. The method according to claim 1,
Wherein the conveying means includes a plurality of rollers, and the plurality of rollers are divided into a plurality of groups in which rotational speeds are individually controlled. A control method of the continuous heat treatment furnace according to claim 1,
a) opening the first door and transferring the object to be processed into the first buffer section;
b) closing the first door and opening the second door;
c) transferring the object to be processed into the replacement section and closing the second door;
d) supplying purge gas to the sealed first buffer section, the second buffer section and the replacement section,
e) removing the purge gas in the displacement section;
f) supplying a purge gas to the replacement section,
g) opening the third door and transferring the object to be processed into the second buffer section,
h) closing the third door and opening the fourth door;
i) transferring the object to be processed out of the second buffer section, and closing the fourth door.

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