JP4385213B2 - Batch heat treatment equipment - Google Patents

Description

The present invention mainly relates to a batch-type heat treatment apparatus used in a manufacturing process including heat treatment such as degreasing, calcination, and firing of multilayer ceramic components such as multilayer ceramic capacitors, ceramic piezoelectric elements, and small multilayer ceramic electronic components such as ceramic resistors.

In recent years, requirements on characteristics of multilayer ceramic parts such as multilayer ceramic electronic parts have become strict, and in particular, uniformity of characteristics has been strongly demanded. Therefore, it is necessary to stabilize and equalize the processing conditions of each manufacturing process, and high-precision control of temperature, atmosphere, etc. is required in the heat treatment apparatus.

In the heat treatment step in the production of ceramic electronic components, usually, a continuous furnace that passes the tunnel-shaped furnace body by placing the object to be heat-treated on a base plate or by placing it on a conveyor belt, or the object to be heat-treated in batches. A batch furnace for heat treatment is used. In general, a continuous furnace is more advantageous in terms of production efficiency for mass production of small varieties. However, in recent years, various types of ceramic electronic components with various characteristics have been required, and the production form has a strong tendency to produce a variety of products in small quantities. Therefore, as a heat treatment device, a batch furnace in which the heat treatment conditions can be easily changed is used. Is increasing.

A general batch furnace used for the production of ceramic electronic components has a structure in which rod-shaped heaters are arranged side by side along the inner wall of a substantially square furnace, or are arranged horizontally in a grid pattern and heated. ing. Accordingly, in plan view, the temperature at the center of the furnace far from the heater is lower than that at the periphery, and the temperature followability is poor. Further, in the vertical direction, due to the convection of the heated atmospheric gas, there is a temperature non-uniformity that the lower part is lower than the upper part.
When the object to be heat-treated is small like an electronic component, the objects to be heat-treated are arranged on a basket or a shelf, and these baskets or shelves are stacked to batch process a large number of objects to be heat-treated at the same time. However, in the conventional batch furnace as described above, the position of the heat treatment object in the furnace is fixed, so the non-uniformity of the temperature in the furnace is the heat treatment temperature non-uniformity of the heat treatment object and the thermal history as it is. It becomes characteristic variation resulting from. In addition, when precise control of the atmosphere in the furnace such as a base metal multilayer capacitor is required, characteristic variations caused by non-uniformity of the atmosphere in the furnace are also induced. Therefore, if a large amount of heat-treated materials are processed in one batch, non-uniformity of quality is caused, and if non-uniformity of quality is reduced, the loading area of the heat-treated materials is limited and productivity is reduced. The problem of falling has arisen.

In order to solve the above problems, it is necessary to ensure both the furnace temperature, the planar uniformity of the atmosphere, and the uniformity in the vertical direction. With respect to ensuring planar uniformity, a method of reducing the position dependency by moving the object to be heat treated in a plane in a furnace is known. In this way, even if there is non-uniformity in temperature, atmosphere, etc. in the furnace, the heat history received by the object to be heat treated is made uniform and the characteristic variation is reduced. For example, there is a method of having a circular hearth that can be rotated, and heat-treating an object to be heat-treated placed on the hearth while rotating in the furnace body.
Japanese Patent Laid-Open No. 2-219997

Further, there is a method of improving the thermal history uniformity by dividing the substantially square hearth into four equal squares and rotating the square turntables on which the workpieces are loaded in each area so as not to contact each other.
JP-A-4-306485

Moreover, as a batch furnace in which the object to be heat-treated revolves, a shaft that penetrates the hearth is provided at a position away from the rotation center of a rotating circular hearth, and this shaft rotates the hearth via a gear. The hearth rotates with the shaft connected to the shaft, and the shaft also rotates. The heat-treated material is placed on a loading platform connected to the shaft and heat-treated while being revolved.
JP-A 63-54587

On the other hand, in order to improve the uniformity of the temperature in the vertical direction, a U-shaped heater having a different heat generating part in the length direction is used, a heater having a heat generating part at the upper part of the furnace body, and a heat generating part at the center part of the furnace body. A heater having a heating part in the lower part of the furnace body in order, and controlling the heater group having the heating part in the upper part, the central part, and the lower part so that the temperature in the vertical direction of the furnace body is uniform is there.
JP-A-5-141875

For the uniform atmosphere, furnace bodies with a special structure have been proposed for applications where a large amount of gas must be introduced and discharged, such as the degreasing process (binder removal) of ceramic green sheets. It is expected that the atmosphere as well as the temperature can be made uniform by moving the object to be heat-treated in the furnace. In particular, for the purpose of positively uniforming the atmosphere, a jig with blades for stirring the atmosphere is placed on the workpiece to be heat-treated placed on the rotating hearth, and the blades are rotated by the rotation of the hearth. And the technique which stirs the gas in a furnace is disclosed.
JP-A-5-172471

In the method of Patent Document 1, the non-uniformity in the diameter direction of the circular hearth cannot be resolved.
The method of Patent Document 2 is uniform in the area where the turntable rotates, but has a problem that the entire furnace is not uniformized.
In the method of Patent Document 3, since the object to be heat-treated is heat-treated while rotating and revolving, the uniformity of planar heat treatment conditions is improved. However, since the object to be heat-treated is placed on the turntable supported by the shaft, there is a problem that if the object to be heat-treated is not placed uniformly, the shaft is inclined and the object to be heat-treated falls from the turntable. It is not suitable for the heat treatment process of ceramic products in which heat-treated products are placed in a heavy bowl and stacked in stages. In addition, since a furnace is also provided at the center of the furnace, the loading area for the multiple heat-treated products is narrowed.
In addition, any of the above methods aims to improve the uniformity of the planar thermal history, and the vertical uniformity is not taken into consideration.

On the other hand, in the method of Patent Document 4, it goes without saying that even if the temperature uniformity in the vertical direction is improved, the uniformity in the entire furnace is not improved. Further, since a heat source is provided at the center of the furnace, the equipment structure is complicated and the cost is increased, and the area to be heat-treated is narrowed.
In the method of Patent Document 5, even if the atmosphere gas in the furnace is stirred by the blades, the gas flow is blocked by the object to be heat treated itself, and a sufficient stirring effect cannot be obtained.

The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to reduce the mounting position dependence of the heat history of the object to be heat-treated both in the plane and in the vertical direction, thereby achieving high quality. An object of the present invention is to provide a batch-type ceramic heat treatment apparatus that can also be used for heat treatment of a variety of small-quantity production such as multilayer ceramic parts.

The present invention includes a furnace body having an inner surface formed of a heat insulating material and a hearth rotatably fitted in a circular opening provided at the bottom of the furnace body in order to heat-treat the object to be heat treated therein. A batch-type heat treatment apparatus that constitutes a cylindrical heat treatment space and that heat-treats an object to be heat-treated placed on the hearth while rotating in the heat treatment space, wherein the hearth is centered on the circular opening. A disc-shaped main hearth that rotates around a passing axis, and a plurality of insertion holes that are drilled at equal intervals on a concentric circle centered on the rotation axis of the main hearth. A plurality of small disk-shaped sub-hearths on which the heat-treated object is placed, and the heat-treated material on the sub-hearth is heat-treated while rotating and revolving. a driving device for revolving with the main hearth while rotating the floor, said the sub hearth, the exposed heat A plurality of stacked refractory metal or ceramic baskets or shelves for mounting a physical object are provided, and the furnace body has a heating source for heating the heat treatment space and an atmosphere gas in the heat treatment space. A gas introduction pipe to be introduced, and the object to be heat-treated placed on the basket or the shelf plate is heat-treated according to a desired temperature and furnace atmosphere profile obtained by the heating source and the gas introduction pipe, The heating source is concentrically suspended or fixed to the side wall between the stacked baskets or shelves and the inner wall heat insulating material of the furnace body having the substantially cylindrical heat treatment space. The plurality of heaters includes an upper heater group that heats the upper part of the furnace body, an intermediate heater group that heats the middle part of the furnace body, and a lower heater group that heats the lower part of the furnace body. Each heater group is equipped with temperature control means for independently controlling the temperature, whereby the desired temperature profile is obtained, and the gas introduction pipe is connected to the furnace from outside the furnace. A horizontal pipe that penetrates the side wall and reaches the inner wall surface of the furnace side wall is provided with a gas header at the front end of the horizontal pipe, or connected to the front end of the horizontal pipe and vertically along the inner wall surface An extending tubular gas header is provided, and the gas header has a plurality of gas ejection holes or slit-shaped gas ejection holes opened in the furnace direction, and the gas ejection holes are formed in the upper heater. The intermediate heater and the lower heater are disposed so as to be located between the furnace inner wall surface and the atmosphere gas from the gas ejection holes are dispersed in the heat treatment space while being heated. Features.

The invention according to claim 2 is the batch heat treatment apparatus according to claim 1, wherein the driving means is configured to transmit the rotational driving force of the main hearth via a transmission mechanism in order to rotate the auxiliary hearth. Thus, it is configured to be transmitted to the rotation shaft of the auxiliary hearth.

According to the first aspect of the present invention, since the object to be heat-treated is placed on the auxiliary hearth and rotates while revolving within the furnace by the main hearth, even if there is some variation in the temperature distribution in the whole furnace. The non-uniformity due to the position dependence of the temperature of the workpiece itself on the secondary hearth is reduced due to the revolution, and for example, the heat treatment is effectively performed within ± 2 ° C. with respect to the furnace temperature of 1200 to 1300 ° C. The same temperature history can be easily achieved and the furnace atmosphere can be stirred and homogenized.
In addition, a heat-treated object placed on a refractory metal or ceramic bowl or shelf stacked in a plurality of stages on the sub-hearth is rotated and revolved, and a heat source provided in the heat treatment space and Since the atmosphere gas introduced into the heat treatment space can be adjusted by the gas introduction tube and heat treatment can be performed at a desired temperature and in-furnace atmosphere profile, various ceramic parts can be heat-treated.
Further, since the heater is suspended and fixed concentrically only on the side wall of the furnace or fixed to the furnace wall, a heater in the central part of the furnace as in the prior art is not required, and the increase in throughput and the structure of the furnace body Simplification and equipment cost reduction are possible.
In addition, since the upper heater group, the middle heater group, and the lower heater group are independently temperature controlled by the temperature control means, it is possible to reduce the temperature distribution above and below the furnace and be required. Heat treatment can be performed more finely at a desired temperature according to the characteristics of various ceramic parts.
In addition, since the atmosphere gas introduced into the heating section of the upper heater, middle heater, and lower heater in the furnace is dispersed in the furnace while being heated by the plurality of gas introduction pipes, the heat treatment atmosphere and temperature are made uniform. Is further promoted.

  According to the invention of claim 2, in addition to having the same effect as that of the invention of claim 1, the auxiliary hearth on which the object to be heat-treated is placed is driven by the transmission mechanism of the drive means. Since the force can be transmitted and rotate, heat treatment is performed by reciprocating the wall of the furnace and the center of the furnace repeatedly, so that the temperature distribution of the heat-treated material placed on the sub-hearth is made uniform. The uniformity of the stirring in the furnace atmosphere is further improved.

Embodiments of the batch heat treatment apparatus of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a plan view of the hearth part of the batch type heat treatment apparatus of the present invention, FIG. 2 is a longitudinal sectional view of the batch type heat treatment apparatus of the present invention, and FIG. 3 is the rotational driving force of the main hearth of one embodiment of the present invention. FIG. 4 is an explanatory view of a gas introduction pipe portion of one embodiment of the present invention, FIG. 5 is an explanatory view of a gas introduction pipe portion of another embodiment of the present invention, and FIG. A transmission mechanism for transmitting the rotational driving force of the main hearth to the auxiliary hearth of another embodiment of the present invention, FIGS. 7 and 8 are explanatory views of a gas introduction pipe section of another embodiment of the present invention.
A batch-type heat treatment apparatus (hereinafter abbreviated as a furnace body) 15 of the present invention has a furnace body having a ceiling portion 16c that has a circular opening 14 at a bottom portion 16b and seals the top of a substantially cylindrical body portion 16a. 16 and a substantially disk-shaped hearth 8 that is rotatably fitted in the opening 14. The gap between the opening 14 and the hearth 8 is set to, for example, 3 to 10 mm so as not to hinder the rotation of the hearth 8 and to minimize the leakage of heat inside the furnace to the outside of the furnace. Both the furnace body 16 and the hearth 8 are formed of a heat insulating material such as ceramic fiber having a thickness of about 50 to 200 mm. An example of the dimensions of the furnace chamber is a cylindrical shape having an inner diameter of 800 mm and a height of 600 mm. The outer surface of the furnace body is covered with a furnace body frame 11 in order to improve the airtightness in the furnace. Furthermore, in order to prevent thermal deformation of the furnace body on the outer wall of the furnace body 16, it is desirable to install a fan (not shown) and air-cool.

As shown in FIG. 2, the hearth 8 includes a main hearth 4 and a secondary hearth 6. The main hearth 4 is held by the hearth frame 23.
Although the main hearth 4 has a substantially disk shape, in detail, as shown in FIG. 2, the cross section has a convex shape, and two large and small disks are vertically stacked. The diameter of the smaller disk is the dimension that fits into the opening 14 of the furnace body 16. The lower large disk is provided to block leakage of radiant heat from the gap between the opening 14 and the main hearth, and the diameter is not particularly limited as long as the diameter fits in the hearth frame 23.
In the main hearth, for example, a plurality of circular insertion holes 4a are formed for rotatably fitting a plurality of small disk-shaped sub hearths 6 having a center concentric with the main hearth 4. ing. Further, a sub hearth holding plate 22 for holding the sub hearth is installed at the bottom of the main hearth 4.
The main hearth 4 is rotated by driving means. In this embodiment, the main hearth 4 has a main hearth rotating shaft 5 that is fixed to the center and extends downward. Is connected to a power source (not shown) such as a motor. Further, the main hearth 4 is held by a hearth frame 23 that is covered by a lower part of the hearth 8 via a tip 20 of the main hearth rotating shaft 5.

The secondary hearth 6 is rotatably fitted in the insertion hole 4a of the main hearth 4 and has a secondary hearth rotating shaft 7 that is fixed at the center and extends downward. The rotational driving force of the main hearth rotating shaft 5 is transmitted to the auxiliary hearth rotating shaft 7 via the transmission mechanism 19, whereby the auxiliary hearth 6 rotates (autorotates). The auxiliary hearth 6 is held by the auxiliary hearth holding plate 22 via the auxiliary hearth rotating shaft 7. That is, the auxiliary hearth 6 revolves around the main hearth rotating shaft 5 together with the main hearth 4 and rotates around the auxiliary hearth rotating shaft 7. The gap between the main hearth 4 and the auxiliary hearth 6 is also set to 3 to 10 mm, for example, similarly to the gap between the opening 14 and the hearth 8.
In FIGS. 1 and 2 of this embodiment, four auxiliary hearths 4 are arranged with the same diameter. The rotation centers are arranged at equal intervals on a concentric circle whose center coincides with the rotation center of the main hearth. An example of the diameters of the main hearth and the secondary hearth are 580 mm and 230 mm, respectively.
The arrangement of the auxiliary hearth 6 is possible in addition to the configuration shown in FIGS. 1 and 2, and the method of holding the main hearth 4 on the hearth frame 23, and holding the auxiliary hearth 4 in the auxiliary hearth 4 Needless to say, various methods can be used to hold the plate 22 such as the peripheral portions of the main hearth and auxiliary hearths by bearings in addition to the present embodiment.

As shown in FIG. 3, the transmission mechanism 19 of the drive means of the present embodiment is provided with pulleys 19a and 19b on the main hearth rotary shaft 5 and the auxiliary hearth rotary shaft 7, respectively, and these are linked by an endless belt 19c. Thus, the rotational power of the main hearth 4 is transmitted to the sub hearth 6. By changing the diameters of the pulleys 19a and 19b of the main hearth rotating shaft 5 and the sub hearth rotating shaft 7, the rotation speed ratio of the main hearth 4 and the sub hearth 6 can be changed. The rotation speed of the main hearth 4 is normally 0.5 to 3 rpm, and the rotation speed of the auxiliary hearth 6 is 1.5 to 2 times that of the main hearth.
According to such a configuration, as indicated by arrows in FIG. 1, all the rotation directions 18 of the auxiliary hearth 6 are the same direction and are opposite to the rotation direction 17 of the main hearth 4. Thereby, since the stirring of the furnace atmosphere is promoted, the temperature distribution of the object to be heat-treated placed on the sub furnace floor and the uniformity of the furnace atmosphere are improved.
Further, for example, as shown in FIG. 6, by changing the method of linking the pulleys 19a and 19b with the endless belt 19c, the rotation directions of the auxiliary hearth 6 are not all the same, and half of them rotate in the reverse direction. This also increases the stirring effect of the furnace atmosphere and further improves the uniformity of the furnace atmosphere.

As the transmission mechanism 19 of the driving means, various configurations such as using a heat-resistant gear, a timing belt, or a chain are possible in addition to the present embodiment. For example, a pulley (sun gear) 19 a attached to the lower end portion of the main hearth rotating shaft 5 and an auxiliary hearth rotating shaft (planetary gear) 7 attached to the lower end portion of the auxiliary hearth rotating shaft 7 are meshed. A kind of planetary gear mechanism can be considered.

The object 9 to be heat-treated is loaded on the auxiliary hearth 6 and heat-treated. In the case of heat treatment such as firing of multilayer ceramic parts, the objects to be heat treated 9 are usually arranged on a basket or a shelf 13 and stacked in multiple stages for heat treatment. The stacked ridges or shelf boards 13 may be further placed on a cylindrical column 13a. The material of the basket or the shelf 13 is selected from materials having heat resistance such as alumina, mullite, nickel metal and the like that do not react with the object 9 to be heat treated.
Even if there is non-uniformity due to the planar position dependence of temperature in the furnace, the non-uniformity received by the workpiece 9 due to the self-revolution of the sub-hearth 6 is small disk-shaped sub-furnace. The range of the radius of the floor 6 is limited to a slight non-uniformity, which is much improved as compared with the conventional batch heat treatment furnace. In the above description, the temperature uniformity is described, but the uniformity is also improved in the atmosphere.

The heater (heating source) 10 for heating the inside of the furnace has a heating element such as a metal, silicon carbide, molybdenum silicite, lanthanum chromite, zirconia, etc., and a rod-like, U-shaped, screw U-shaped, etc. And the thing of the shape which has the terminal which supplies a power supply in one direction of rod shape is preferable. Or it is also possible to make it a structure which makes a terminal part penetrate a furnace wall.
In the present embodiment, a plurality of U-shaped heaters 10 are suspended and fixed from the ceiling portion 16 c of the furnace body 16 along the inner wall of the substantially cylindrical body portion 16 a of the furnace body 16. The plurality of heaters 10 includes an upper heater group that heats the upper part of the furnace body 16, an intermediate heater group that heats a height part of the middle part of the furnace body 16, and a lower heater group that heats the lower part of the furnace body 16. By controlling the temperature of each heater group independently by temperature control means (not shown), the temperature uniformity in the vertical direction in the furnace is improved. As shown in FIG. 1, the heater 10 that heats the upper, middle, and lower portions of the furnace body 16 has an upper portion, an intermediate portion, and a lower heater 1 that have heating portions in the upper portion, the middle portion, and the lower portion, respectively. 2,3. In this embodiment, as shown in FIG. 1, a total of 12 upper, middle and lower heaters 1, 2, 3 are arranged in order. The upper, middle, and lower heaters 1, 2, and 3 have the same length of the heat generating portion, the length of the mounting portion (terminal portion) is different, and the heat generating portion has a predetermined height. Choose a mounting length. In FIG. 2, only the heat generating portion of the lower heater 3 is displayed so as to overlap the upper heater 1.
In this embodiment, the heater 10 is suspended and fixed from the ceiling portion 16c of the furnace body 16, but the heater 10 may be fixed to the side wall of the body portion 16a.

When the effective height at which the workpieces 9 can be stacked is 400 mm, for example, the intermediate heater 2 that heats the intermediate portion has a heating portion length of 200 mm, and the center of the heating portion is the workpiece to be heat treated. It fixes so that it may correspond to the center position of 9. The upper heater 1 that heats the upper part and the lower heater 3 that heats the lower part also have a heating part with a length of 200 mm, and the center of the heating part is 150 mm above and below the center of the workpiece 9 respectively. The position should be 150 mm. The position where the heater is arranged in a plane can be appropriately changed according to the dimensions of the furnace chamber, the required temperature accuracy, and the like.

Next, adjustment of the atmosphere in the furnace chamber will be described.
4, 5, 7 and 8 show one embodiment of the gas introduction pipe for introducing the atmospheric gas into the furnace and another embodiment, respectively, and the embodiments of FIGS. 4 and 5 and FIGS. 7 and 8 will be described later. These are the same except that the shape and configuration of the gas ejection holes are different.
4 is connected to the horizontal pipe 31a from the outside of the furnace through the furnace side wall of the body portion 16a of the furnace main body 16 to reach the inner wall surface of the furnace side wall, and the horizontal wall 31a at the inner wall surface. A tubular gas header 31b extending in the vertical direction and having a plurality of small gas ejection holes 31c along the inner wall surface of the furnace. The atmospheric gas is introduced from the outside of the furnace into the furnace chamber through the horizontal pipe 31a, and is dispersed into the furnace chamber from the gas ejection holes 31c of the gas header 31b. At this time, if the atmospheric gas having a temperature lower than that in the furnace chamber is dispersed, the temperature in the furnace chamber is lowered. Therefore, the atmospheric gas is preferably heated and dispersed in the furnace chamber. In the present embodiment, as shown in FIG. 2, three gas introduction pipes, that is, an upper gas introduction pipe 31, a central part gas introduction pipe 32, and a lower gas introduction pipe 33 are provided with respective gas headers 31b, 32b, 33b. Are arranged so as to face the heating portions of the U-shaped upper heater 1, intermediate heater 2, and lower heater 3, respectively.

Due to the arrangement of the upper, middle, and lower three-stage gas introduction pipes, the atmospheric gas is uniformly distributed in the vertical direction from the gas headers 31b, 32b, and 33b to the furnace chamber, and is heated by a heater facing the gas header. The heat-treated product 9 is reached. Therefore, the uniformity of the atmosphere and temperature is improved, and a separate gas heating device is not required, so that the device is simplified, which is advantageous in terms of economy and space.
In addition, when it is necessary to control the furnace chamber atmosphere more precisely, the gas composition and flow rate introduced from each gas introduction pipe are individually controlled.
The gas ejection holes of the gas headers 31b, 32b, 33b are formed in a circular hole 31c of 0.5 to 3 mmφ in the embodiment of FIG. 4 and are arranged at equal intervals in the length direction of the header 31b.
Further, in the embodiment of FIG. 5, the gas ejection holes 31d are formed in a slit shape of an oblong long hole shape having a width of 0.2 to 1.0 mm extending in the length direction of the header.
Moreover, the gas introduction pipes of the embodiment of FIGS. 7 and 8 penetrate the furnace side wall of the body portion 16a of the furnace body 16 from the outside of the furnace as shown in FIGS. 7 (a) and 8 (a), respectively. The tip (wall surface) of the horizontal pipe 31a reaching the inner wall surface of the side wall is hemispherical, and this hemispherical portion is the gas header 31b.
In the embodiment of FIG. 7, as shown in FIG. 7 (b) [view of the gas header 31b viewed from the direction A in FIG. 7 (a)], a plurality of small holes of 0.5 to 3.0 mmφ are formed in the gas header 31b. The gas ejection holes 31c are formed in a line in the vertical direction of the furnace body.
Further, in the embodiment of FIG. 8, as shown in FIG. 8B [the view of the gas header 31b seen from the direction B in FIG. 8A], the gas header 31b has a width of 0.2 to 1.0 mm and a long length. A slit-like gas ejection hole 31d having a length of about 6 mm is formed so that the longitudinal direction of the slit coincides with the vertical direction of the furnace body.
When using the gas introduction pipes of FIGS. 5, 7 and 8, as described above, the furnace is constructed in three stages of upper, middle and lower so that the gas header faces the heating parts of the upper heater 1, the intermediate heater 2 and the lower heater 3. It is preferable to arrange in the body.

Further, a heat-resistant sealing means 23a is provided on the entire upper end of the hearth frame 23 formed in a bottomed cylindrical shape so as to cover the lower part of the hearth 8 and the transmission mechanism 19, and this heat resistance is provided. The sealing means 23a is kept in contact with the furnace body frame 11 on the lower surface of the bottom 16b of the furnace body 16, thereby maintaining the airtightness in the furnace.
A gas discharge hole (not shown) for discharging the atmosphere gas in the furnace chamber to the outside of the furnace is appropriately arranged by providing a damper whose discharge amount can be adjusted according to the introduction amount of the atmosphere gas.

When the workpiece 9 is put in and out of the furnace body 16, the hearth 8 on which the workpiece 9 is placed is lowered relative to the furnace body 16 together with the hearth frame 23, and the workpiece 9 is placed on the hearth 8. The structure is such that a sufficient space for placing or taking out can be secured. For example, the hearth 8 can be raised and lowered by raising and lowering the hearth frame 23 with a screw jack (not shown). When the hearth frame 23 rises, the hearth frame 23 and the furnace body frame 11 on the lower surface of the bottom 16b of the furnace body 16 come into contact with each other through the heat-resistant sealing means 23a, and the inside of the furnace is kept airtight.
With this configuration, for example, in the case of firing a ceramic component having a base metallization layer such as nickel or copper, several ppm of water is introduced using nitrogen gas as a carrier gas, and the partial pressure of oxygen is 10 ^−. An atmosphere suppressed to ⁸ to 10 ⁻¹⁴ atm can be formed.

The batch type heat treatment apparatus according to the present invention, as explained above and as described in detail in the section of the effect of the invention, makes the temperature distribution uniform and the furnace atmosphere by the self-revolution of the material to be heat-treated placed on the sub hearth. In addition to the stirring effect of the above, individual temperature control of the upper, middle and lower heater groups and the upper, middle, and lower three-stage gas introduction pipes that uniformly disperse the atmospheric gas in the furnace chamber provide high accuracy and high uniformity Desired temperature and furnace atmosphere profile can be set. Therefore, it can be used for high-precision heat treatment of various recent high-performance multilayer ceramic parts.

It is a top view of the hearth part of the batch type heat processing apparatus of one Example of this invention. It is a longitudinal cross-sectional view of the batch type heat processing apparatus of one Example of this invention. It is a transmission mechanism of the batch type heat processing apparatus of one Example of this invention. It is explanatory drawing of the gas introduction pipe | tube part of the batch type heat processing apparatus of one Example of this invention. It is a form of the gas introduction pipe | tube of the batch type heat processing apparatus of another Example of this invention. It is a transmission mechanism of the batch type heat processing apparatus of another Example of this invention. (A) It is the form of the gas introduction pipe | tube of the batch type heat processing apparatus of another Example of this invention. (B) It is a form of the gas ejection hole of the gas introduction pipe | tube of the batch type heat processing apparatus of another Example of this invention. (A) It is the form of the gas introduction pipe | tube of the batch type heat processing apparatus of another Example of this invention. (B) It is a form of the gas ejection hole of the gas introduction pipe | tube of the batch type heat processing apparatus of another Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper heater 2 Middle heater 3 Lower heater 4 Main hearth 4a Insertion hole 5 Main hearth rotating shaft 6 Sub hearth 7 Sub hearth rotating shaft 8 Furnace 9 Heat processing object 10 Heater 11, 21 Furnace frame 12 Thermal insulation material 13 Napishtim or shelf plate 13a strut 14 opening 15 furnace 16 furnace body 16a torso portion 16b bottom portion 16c ceiling 17 main hearth rotation direction 18 sub hearth rotation direction 19 transmission mechanism 19a, 19b pulley 19c belt 20 main furnace Floor rotary shaft tip 22 Sub hearth holding plate 23 Hearth frame 23a Heat-resistant sealing means 31 Upper gas introduction pipes 31a, 32a, 33a Horizontal pipes 31b, 32b, 33b Gas header 31c Gas ejection holes (small holes)
31d Gas ejection hole (long hole slit shape)
32 Central gas introduction pipe 33 Lower gas introduction pipe

Claims (2)

In order to heat-treat the material to be heat treated inside, a substantially cylindrical heat treatment is performed by a furnace body whose inner surface is formed of a heat insulating material and a hearth rotatably fitted in a circular opening provided at the bottom of the furnace body. A batch-type heat treatment apparatus that constitutes a space and heat-treats an object to be heat-treated placed on a hearth while rotating in the heat treatment space,
The hearth is a disk-shaped main hearth that rotates around an axis that passes through the center of the circular opening;
A plurality of small disks that are rotatably fitted in a plurality of insertion holes that are arranged at equal intervals on a concentric circle centered on the rotation axis of the main hearth, and on which the object to be heat-treated is placed A secondary hearth and
In addition, drive means for revolving the sub hearth and revolving together with the main hearth so that the heat-treated material on the sub hearth is revolved while revolving,
On the sub-hearth, a plurality of stacked refractory metal or ceramic ridges or shelves for mounting the object to be heat-treated are equipped, and the furnace body is heated to heat the heat treatment space. And a gas introduction pipe for introducing an atmospheric gas into the heat treatment space, and the object to be heat-treated placed on the basket or the shelf plate has a desired temperature obtained by the heating source and the gas introduction pipe. And heat treated according to the furnace atmosphere profile,
The heating source is
Consists of a plurality of heaters that are concentrically suspended or fixed to the side wall between the stacked baskets or shelf plates and the inner wall heat insulating material of the furnace body having the substantially cylindrical heat treatment space. ,
The plurality of heaters are:
An upper heater group for heating the upper part of the furnace body;
An intermediate heater group for heating the intermediate part of the furnace body;
It consists of a lower heater group that heats the lower part of the furnace body,
Each heater group is equipped with a temperature control means for independently controlling the temperature, whereby the desired temperature profile can be obtained,
The gas introduction pipe is provided with a gas header at the tip of the horizontal pipe or connected to the tip of the horizontal pipe in a horizontal pipe that reaches the inner wall surface of the furnace side wall through the furnace side wall from the outside of the furnace. In addition, a tubular gas header extending in the vertical direction along the inner wall surface is provided, and the gas header has a plurality of gas ejection holes or slit-shaped gas ejection holes opened toward the furnace inner direction. ,
The gas ejection hole is disposed between each of the upper heater, the intermediate heater, and the lower heater and a wall surface of the furnace, and the heat treatment space is heated while the atmospheric gas from the gas ejection hole is heated. A batch-type heat treatment apparatus characterized by being dispersed in a batch. In order to rotate the auxiliary hearth, the drive means is configured to transmit the rotational driving force of the main hearth to the rotating shaft of the auxiliary hearth via a transmission mechanism. The batch type heat treatment apparatus according to claim 1.

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