JP7110281B2 - Binder removal furnace - Google Patents

Description

The present invention relates to a debindering furnace for removing, by heat treatment, binders that bind main materials such as metal powders and inorganic powders in powder compacts.

For example, when forming powder compacts such as press molding, injection molding, extrusion molding, etc., as a molding aid for improving homogenization, plasticity, moldability, shape retention, etc. for main materials such as metal powders and inorganic powders. Binders such as paraffins, waxes, camphor, etc., are incorporated. Prior to the step of sintering the powder compact, a binder removal (degreasing) step may be performed in the air, in an inert gas, in a vacuum, or the like. In the binder removal step, a heat treatment is performed to remove the binder added during the molding of the powder compact in order to prevent the binder from becoming a detriment to maintaining sintering quality in the sintering step.

As a debindering furnace that also removes the binder, a sintering furnace for powder metallurgy described in Patent Document 1 has been proposed. This sintering furnace for powder metallurgy is provided with a furnace body inside a cooling jacket that forms the outer wall of the furnace body, and heats an object to be heated contained in the furnace body to, for example, 200° C. or higher with a heating element, A binder such as paraffin contained in the object to be heated is liquefied and dripped from the table on which the object to be heated is placed, and is recovered in a recovery tank through a discharge port.

Japanese Patent Publication No. 58-9868

However, in the powder metallurgy sintering furnace described in Patent Document 1, the binder contained in the object to be heated is liquefied and removed, but the volatilized binder stays in the furnace body. When sintering is performed inside, there is a problem that sufficient sintering quality may not be obtained due to the volatilized binder.

The present invention has been made against the background of the above circumstances, and its object is to facilitate removal of the binder generated from the heated object from the furnace main body, and to improve the sintering quality in the sintering in the furnace main body. To provide a debindering furnace capable of sufficiently obtaining binders.

As a result of various investigations in order to solve the above problems, the inventor of the present invention introduced a gas such as an inert gas in the atmosphere into the furnace body accommodated in the space formed by the outer wall of the heating furnace. A passage is provided for diluting the binder emitted from the object to be heated contained in the furnace main body with the gas and leading it out of the furnace main body, and the gas containing the binder emitted from the furnace main body is brought into contact with the cooling jacket. It was found that the binder volatilized from the object to be heated is captured by the cooling jacket and efficiently recovered when the object to be heated is exhausted to the outside of the heating furnace. The present invention has been made based on this finding.

That is, the gist of the present invention is (a) a furnace wall having a top wall, a bottom wall, and four side walls connecting the top wall and the bottom wall to form a heating space; For a furnace body having a heater for heating an object to be heated housed in the heating space, the upper wall of the furnace wall, the bottom wall, and four side walls connecting the top wall and the bottom wall , and an outer wall for accommodating the furnace main body, which is composed of a lower outer wall, an upper outer wall, and four lateral outer walls facing each other with a predetermined gap, wherein (b (c) a gas supply pipe for introducing gas into the furnace main body; (d) an exhaust pipe extending through said upper outer wall of said outer wall; (e) said furnace (e) cooling jackets provided on at least a portion of the walls so as to face each other via a gas flow path from the degassing hole to the exhaust pipe; (f) the gas supply pipes inject the gas in opposite At least one pair of gas supply pipes, wherein one of the pair of gas supply pipes is provided in a state of penetrating only the upper portion of one of the pair of opposite side walls of the four side walls, and the pair of gas supply pipes (g) the degassing hole extends through the at least one pair of gas supply pipes; are provided through the bottom wall in a larger number than the The gas is led to the space between the bottom wall and the lower wall facing the bottom wall at a flow rate lower than the introduction speed of the degassing holes.

According to the debindering furnace of the present invention, a gas supply pipe for introducing gas into the furnace body and a binder that is provided through the furnace wall and volatilized from the gas and the object to be heated in the furnace body are discharged. a degassing hole leading to a space between the bottom wall of the furnace wall and the lower outer wall portion of the outer wall; an exhaust pipe provided through the upper outer wall portion of the outer wall; a cooling jacket provided on at least a part of the wall so as to face each other via a gas flow path from the degassing hole to the exhaust pipe. For this reason, a one-way path is provided to guide the binder discharged from the object to be heated contained in the furnace main body to the outside of the furnace main body while diluting it with the gas supplied into the furnace main body through the gas supply pipe, The binder-containing gas discharged from the furnace body through the degassing holes is exhausted out of the binder removal furnace through the exhaust pipe while contacting the cooling jacket along the cooling jacket. As a result, the binder volatilized from the object to be heated is prevented from remaining in the furnace body, and is captured by the cooling jacket and collected efficiently, so that the binder generated from the object to be heated is easily removed from the furnace body. , sufficient sintering quality is obtained in sintering in the furnace body.
Further, the furnace wall has a top wall, a bottom wall, and four side walls connecting the top wall and the bottom wall , and (f) the cooling jacket has a are arranged to face each other with the same gap through the gas distribution path from the degassing hole to the exhaust pipe, so that the binder in the gas does not Efficiently trapped in the cooling jacket.
Further, the gas supply pipes are at least a pair of gas supply pipes for injecting the gas to face each other, and one of the pair of gas supply pipes is one of the pair of side walls facing each other among the four side walls. The other of the pair of gas supply pipes is provided in a state of penetrating only one upper portion, and the other of the pair of gas supply pipes is provided in a state of penetrating only the upper portion of the other of the pair of side walls facing each other out of the four side walls, (h) The degassing holes are provided through the bottom wall in a number greater than that of the at least one pair of gas supply pipes, and have a flow cross-sectional area larger than that of the gas supply pipes. and guides the gas and the binder volatilized from the object to be heated to the space between the bottom wall and the lower wall facing the bottom wall at a flow velocity lower than the introduction velocity of the degassing hole. . As a result, a unidirectional flow of gas from the upper side to the lower side through the degassing holes is formed gently in the furnace body, so that the binder generated from the object to be heated can easily escape from the furnace body. A sufficient sintering quality is obtained in sintering in the furnace body. In addition, since the flow of gas flowing through the degassing holes to the exhaust pipe is moderated and turbulence is suppressed, the binder contained in the gas is efficiently captured and collected by the cooling jacket.

Here, preferably, the heaters are provided on the top wall, the bottom wall, and the four side walls, respectively. As a result, the object to be heated is uniformly heated by the heaters respectively provided on the bottom wall, the upper wall, and the four side walls of the furnace wall, so that the binder removal is efficiently performed in a short time.

Preferably, the lower outer wall facing the bottom wall is provided with a tar drain pipe with an on-off valve for discharging the tar accumulated in the lower outer wall. Thus, by opening the on-off valve, the tar accumulated on the lower outer wall portion is collected in the tar receiving container.

Preferably, the lower outer wall portion is provided with an inclined surface that becomes lower toward the tar drain pipe. As a result, the tar accumulated on the lower outer wall portion is efficiently collected in the tar receiving container.

Preferably, the exhaust pipe is provided through an upper outer wall portion of the outer wall located above the furnace main body, and the upper outer wall portion has an inclination that becomes higher toward the exhaust pipe. face is provided. As a result, dripping of tar from the upper outer wall portion is suppressed, and contamination of the furnace main body is reduced.

Preferably, when the binder removal process for the object to be heated is completed, the furnace body is arranged to remove the object to be heated while the object to be heated is positioned in the furnace body following the binder removal process. sintering treatment is performed. As a result, there is an advantage that the binder removal process and the sintering process are continuously performed within the furnace body.

1 is a schematic diagram showing a horizontal cross section of a binder removal furnace according to an embodiment of the present invention; FIG. FIG. 2 is a schematic view showing a vertical cross section of the binder removing furnace of FIG. 1; FIG. 2 is a perspective view schematically showing a gas flow path of the binder removal furnace of FIG. 1; FIG. 3 is a schematic diagram showing a vertical cross-section of a binder removal furnace according to another embodiment of the present invention, corresponding to FIG. 2;

An embodiment of the present invention will now be described in detail with reference to the drawings. In the following examples, the drawings are intended to explain the essential parts related to the invention, and the dimensions, shapes, etc. are not necessarily drawn accurately.

FIG. 1 is a schematic diagram showing a horizontal section of a binder removal furnace 10 according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing a longitudinal section of the binder removal furnace 10, and FIG. FIG. 4 is a schematic perspective view explaining a route F with a dashed line;

In general, when forming powder compacts such as press molding, injection molding, extrusion molding, etc., it is used as a molding aid to improve homogenization, plasticity, moldability, shape retention, etc. for main materials such as metal powders and inorganic powders. Binders such as paraffins, waxes, camphor, etc., are incorporated. In order to prevent the binder from becoming a detriment to maintaining the sintering quality when sintering the powder compact, the binder is removed in the air, in an inert gas, in a vacuum, etc. prior to sintering the powder compact. (degreasing) is performed. In the binder removal furnace 10, a heat treatment is performed to remove the binder added to the object to be heated W, which is such a powder compact, prior to sintering the object.

As shown in FIGS. 1 and 2, the binder removal furnace 10 includes a furnace main body 12 having a rectangular parallelepiped heating space E1 in which a plurality of heaters H for heating an object W to be heated is provided, and a furnace main body 12. A rectangular parallelepiped outer wall 14 airtightly covers the furnace body 12 and airtightly accommodates the furnace body 12 with predetermined gaps Ea, Eb, Ec, Ed, Ee, and Ef. The binder removal furnace 10 of this embodiment is of a batch type, and an opening/closing mechanism (not shown) for opening and closing, for example, a side wall 16c and a lateral wall portion 14c, which will be described later, is provided in the furnace body 12 and the outer wall 14 in order to put in and take out the object W to be heated. is provided.

The furnace body 12 is provided with a furnace wall 16 made of a highly heat-insulating material such as ceramic fiber and having a constant thickness. It is composed of four side walls 16c, 16d, 16e and 16f connecting 16a and top wall 16b. The heaters H are provided on a bottom wall 16a, an upper wall 16b, and four side walls 16c, 16d, 16e, and 16f of the furnace wall 16 so as to surround the object W to be heated.

The outer wall 14 is divided into a bottom wall 16a, a top wall 16b, and four side walls 16c, 16d, 16e, and 16f with predetermined gaps Ea, Eb, Ec, Ed, Ee, and Ef therebetween so as to form a gas flow path F. It is composed of a lower outer wall portion 14a, an upper outer wall portion 14b, and four lateral outer wall portions 14c, 14d, 14e, and 14f, which face each other. The lower outer wall portion 14a and the upper outer wall portion 14b are connected by four horizontal outer wall portions 14c, 14d, 14e, and 14f to form an airtight space for accommodating the furnace body 12. As shown in FIG.

The lower outer wall portion 14a, the upper outer wall portion 14b, and the four horizontal outer wall portions 14c, 14d, 14e, and 14f are double-structured plate materials separated by a space for circulating a coolant such as water or coolant through a coolant pipe 15. , it functions as a cooling jacket provided on the outer wall 14 .

In the furnace wall 16 of the furnace body 12, an inert gas supply pipe penetrating through the lateral outer wall portions 14d and 14f is provided above a pair of opposing side walls 16d and 16f among the four side walls 16c, 16d, 16e and 16f. Two each are provided in a state in which the distal end portions of 18 are penetrated. The inert gas supply pipe 18 functions as the gas supply pipe of the present invention. Of the inert gas supply pipes 18, the inert gas supply pipe 18 provided on the side wall 16d and the inert gas supply pipe 18 provided on the side wall 16f are in a state in which the inert gas G is jetted to face each other. Then, an inert gas G such as nitrogen gas or argon gas is introduced into the furnace body 12 .

In the bottom wall 16a of the furnace body 12, a plurality of degassing holes 20, for example, 16, which are larger in number than the number of the inert gas supply pipes 18, are formed through the thickness direction. is larger than that of the inert gas supply pipe 18. Therefore, the flow velocity of the inert gas G in the degassing hole 20 is significantly lower than the inflow velocity in the inert gas supply pipe 18 . The degassing hole 20 removes the binder and inert gas G volatilized from the object to be heated W in the furnace body 12 between the bottom wall 16a and the lower wall portion 14a facing the bottom wall 16a below the bottom wall 16a. lead to the space of

At the center of the upper wall portion 14b located above the furnace body 12, an exhaust pipe 22 for discharging the inert gas G flowing out from the degassing hole 20 by natural exhaust or forced exhaust is provided at the center of the upper wall portion 14b. It is provided so as to penetrate the upper outer wall portion 14b. In addition, a plurality of tar drain pipes 28 with on-off valves 26 for discharging the tar accumulated on the lower outer wall portion 14a to the tar receiver 24 are provided in the lower outer wall portion 14a positioned below the furnace body 12. there is

In the debindering furnace 10 configured as described above, when the inert gas G is introduced into the furnace main body 12 in a facing state through the pair of inert gas supply pipes 18, it stays in the upper part of the furnace main body 12. A flow of the inert gas G is formed in which the inert gas G is directed toward the degassing holes 20 from the top thereof. In this state, when the object to be heated W in the furnace body 12 is heated to, for example, about 200° C. by the heater H and a binder is generated from the object to be heated W, the binder is diluted with the inert gas G flowing toward the degassing hole 20 . Since it passes through the degassing holes 20 together with the unidirectional flow of the inert gas G while being heated, the binder generated from the object W to be heated is easily removed from the furnace main body 12 and is suppressed from remaining on the object W to be heated. be. As a result, sufficient sintering quality can be obtained when the object W to be heated is sintered.

The inert gas G containing the binder, which is led out of the furnace main body 12 by passing through the degassing holes 20, passes through the bottom wall 16a and the lower wall portion 14a, as indicated by the dashed arrows in FIGS. Through the space between, the space between the side walls 16c, 16d, 16e, 16f and the lateral wall portions 14c, 14d, 14e, 14f, the space between the upper wall 16b and the upper wall portion 14b, the upper wall portion 14b It is discharged to the outside from an exhaust pipe 22 provided in the central part of the. The gas flow path F from the degassing hole 20 of the inert gas G containing this binder to the exhaust pipe 22 is formed by the inner wall surface of the lower outer wall portion 14a functioning as a cooling jacket and the inner wall portions of the lateral outer wall portions 14c, 14d, 14e, and 14f. In the process of moving along the wall surface and the inner wall surface of the upper outer wall portion 14b, the binder condenses on the inner wall surface and is caught, and flows down as indicated by the solid-line arrow D in FIG. stay in

Spaces between the side walls 16c, 16d, 16e, 16f and the lateral wall portions 14c, 14d, 14e, 14f in the gas flow path F from the degassing hole 20 of the inert gas G containing the binder to the exhaust pipe 22 Since there are four points, the cross-sectional area of the flow passage is larger than the space between the bottom wall 16a and the lower outer wall portion 14a and the space between the upper wall 16b and the upper outer wall portion 14b. Condensation easily occurs, resulting in high trapping efficiency.

Then, when the binder removal processing period for the object W to be heated for removing the binder was completed, the heater H in the furnace body 12 set the temperature of the object W to be heated to a temperature higher than the binder removal treatment temperature, for example, 1200° C. or higher. The temperature is raised to the sintering temperature and held for a predetermined period of time. As a result, the object W to be heated is sintered while it is positioned inside the furnace body 12 .

As described above, according to the binder removal furnace 10 of the present embodiment, the furnace body 12 having the furnace wall 16 forming the heating space E1 and the heater H for heating the object W housed in the heating space E1; A debindering furnace 10 having an outer wall 14 for accommodating the furnace body 12 with predetermined gaps Ea, Eb, Ec, Ed, Ee, and Ef from the furnace body 12, wherein an inert gas is introduced into the furnace body 12. The inert gas supply pipe 18 for introducing G and the furnace wall 16 of the furnace body 12 are provided to pass through, and the inert gas G and the binder volatilized from the object to be heated W are supplied to the lower outer wall facing the bottom wall 16a. A degassing hole 20 leading to the space between 14a and the bottom wall 16a, an exhaust pipe 22 provided through the outer wall 14, and a gas flow path F from the degassing hole 20 to the exhaust pipe 22 are sandwiched between the furnace. and a cooling jacket 14 positioned opposite at least a portion of the wall 16 .

For this reason, the degassing hole 20 is removed while diluting the binder discharged from the object to be heated W housed in the furnace main body 12 with the inert gas supplied into the furnace main body 12 through the plurality of inert gas supply pipes 18 . A one-way passage is provided to lead to the outside of the furnace body 12 through the furnace body 12, and the inert gas G containing the binder discharged from the furnace body 12 through the degassing holes 20 contacts the inner wall surface of the outer wall 14 functioning as a cooling jacket. while being exhausted to the outside of the binder removal furnace 10 through the exhaust pipe 22 . As a result, the binder volatilized from the object to be heated W does not remain in the furnace body 12, and is efficiently collected by being captured by the inner wall surface of the outer wall 14 functioning as a cooling jacket. The binder can be easily removed from the furnace main body 12, and high sintering quality of the object W to be heated can be obtained in the sintering in the furnace main body 12. - 特許庁

According to the debindering furnace 10 of the present embodiment, the degassing hole 20 is provided through the bottom wall 16a of the furnace wall 16 of the furnace body 12, and the binder volatilized from the inert gas and the object W to be heated. to the space between the bottom wall 16a and the bottom wall portion 14a located below the bottom wall 16a and facing the bottom wall 16a. As a result, the inert gas flows in one direction from the inert gas supply pipe 18 to the degassing hole 20 formed in the bottom wall 16a in the furnace body 12, so that the inert gas volatilizes from the object W to be heated. Since the binder does not stay in the furnace body 12 and is flowed out of the furnace body 12 together with the inert gas, the binder can be easily removed from the furnace body 12 .

According to the binder removal furnace 10 of this embodiment, the furnace wall 16 has a bottom wall 16a, a top wall 16b, and four side walls 16c, 16d, 16e, and 16f connecting the bottom wall 16a and the top wall 16b. The outer wall 14 functioning as a cooling jacket is arranged so as to face at least four side walls 16c, 16d, 16e, and 16f through the gas flow path F from the degassing hole 20 to the exhaust pipe 22. ing. As a result, in the gas flow path F from the degassing hole 20 to the exhaust pipe 22, the four lateral outer wall portions 14c, 14d, 14e, 14f and the four side walls 16c, 16d, 16e, 16f of the outer wall 14 functioning as cooling jackets are formed. , the binder in the inert gas G is efficiently trapped on the inner wall surfaces of the lateral outer wall portions 14c, 14d, 14e, and 14f functioning as cooling jackets.

According to the binder removal furnace 10 of this embodiment, the furnace wall 16 has a bottom wall 16a, a top wall 16b, and four side walls 16c, 16d, 16e, and 16f connecting the bottom wall 16a and the top wall 16b. The heaters H are provided on the bottom wall 16a, top wall 16b, and four side walls 16c, 16d, 16e, and 16f of the furnace wall 16, respectively. As a result, the object to be heated W is uniformly heated by the heaters H provided on the bottom wall 16a, the upper wall 16b, and the four side walls 16c, 16d, 16e, and 16f of the furnace wall 16, so that the binder is removed. Efficient in a short time.

According to the binder removal furnace 10 of this embodiment, the inert gas supply pipes 18 are at least a pair of inert gas supply pipes 18 for injecting the inert gas G in opposite directions. One of the pair of side walls 16c, 16d, 16e, and 16f is provided so as to penetrate the upper part of one of the pair of side walls 16d and 16f facing each other, and the other of the pair of inert gas supply pipes 18 is It is provided so as to pass through the upper portion of the other of the pair of side walls 16d and 16f facing each other among the four side walls 16c, 16d, 16e and 16f. As a result, a unidirectional passage for the inert gas is formed in the furnace body 12 from the top to the bottom and passes through the degassing holes 20 , so that the binder generated from the object to be heated W escapes from the furnace body 12 . The sintering quality is sufficiently obtained in the sintering in the furnace main body 12 .

According to the binder removal furnace 10 of this embodiment, the plurality of degassing holes 20 provided through the bottom wall 16a are larger in number than the number of the inert gas supply pipes 18. The inert gas G is introduced into the space between the bottom wall 16a and the lower wall portion 14a facing the bottom wall 16a at a flow rate lower than the introduction speed of the bottom wall 16a. As a result, the flow of the inert gas passing through the degassing hole 20 and toward the exhaust pipe 22 is moderated and turbulence is suppressed, so that the binder contained in the inert gas G prevents the outer wall 14 from functioning as a cooling jacket. It is efficiently caught and collected by the inner wall surface.

According to the debindering furnace 10 of the present embodiment, the lower outer wall portion 14a facing the bottom wall 16a is provided with the tar drain pipe 28 with the on-off valve 26 for discharging the tar accumulated on the lower outer wall portion 14a. . Thus, by opening the on-off valve 26, the tar accumulated on the lower outer wall portion 14a is collected in the tar receiver 24. As shown in FIG.

According to the binder removal furnace 10 of the present embodiment, when the binder removal processing of the object W to be heated is completed, the furnace main body 12 starts the binder removal treatment while the object W to be heated is still positioned in the furnace main body 12 . Subsequently, the object W to be heated is subjected to sintering treatment. Accordingly, there is an advantage that the binder removal process and the sintering process are continuously performed within the furnace body 12 .

Next, a debindering furnace 110 according to another embodiment of the present invention will be described with reference to FIG. In addition, the same reference numerals are given to the parts common to the above-described embodiment, and the description thereof will be omitted.

In FIG. 4, the binder removal furnace 110 differs from the binder removal furnace 10 in terms of the shape of the lower wall portion 14a facing the bottom wall 16a and the shape of the upper wall portion 14b facing the upper wall 16b. is.

An inner wall surface of the lower outer wall portion 14a facing the bottom wall 16a is provided with an inclined surface S1 that becomes lower toward the opening of the tar drain pipe 28. As shown in FIG. An inner wall surface of the upper outer wall portion 14b facing the upper wall 16b is provided with an inclined surface S2 that becomes higher toward the exhaust pipe 22. As shown in FIG.

According to this embodiment, in addition to obtaining the same effects as those of the above-described embodiments, the tar accumulated on the lower wall portion 14a is efficiently collected in the tar receiver 24 by the inclined surface S1. . In addition, the inclined surface S2 prevents tar from dripping onto the furnace body 12 from the upper outer wall portion 14b, thereby reducing contamination of the furnace body 12. As shown in FIG.

Although the present invention has been described in detail with reference to the drawings, the present invention is also applicable in other aspects.

For example, in the embodiment described above, the entire outer wall 14 was constructed as a cooling jacket. However, even if a portion of the outer wall 14, such as the lateral outer wall portions 14c, 14d, 14e, and 14f, is configured as a cooling jacket made of a double structure plate material, a suitable binder removal function can be obtained. Also, the cooling jacket may be provided on the inner side of the outer wall 14 .

Although the binder removal furnaces 10 and 110 of the above-described embodiments are of the batch type, the binder removal area for the purpose of removing the binder from the object to be heated W, for example, having a cross-sectional structure similar to that of FIG. 2 or FIG. A continuous heating furnace provided with a sintering area for the purpose of sintering the object W to be heated subsequently may be used.

In the debindering furnaces 10 and 110 of the above-described embodiments, two pairs of inert gas supply pipes 18, ie, four, were provided. The number may be one or more.

In the binder removal furnaces 10 and 110 of the above-described embodiments, a plurality of degassing holes 20 were provided. may be one.

In addition, in the binder removal furnace 10 of the above-described embodiment, the gaps Ec, Ed, Ee, and Ef may or may not be the same intervals.

Further, in the debindering furnaces 10 and 110 of the above-described embodiments, the exhaust pipe 22 is provided to pass through the upper outer wall portion 14b. may be provided.

In addition, in the debindering furnaces 10 and 110 of the above embodiments, the degassing holes 20 are provided through the bottom wall 16a of the furnace wall 16, but any of the side walls 16c, 16d, 16e, and 16f are provided. may be provided through the

Further, in the debindering furnaces 10 and 110 of the above-described embodiments, the furnace body 12 has a rectangular parallelepiped shape, but may have a cylindrical or spherical shape. Similarly, although the outer wall 14 that accommodates the furnace body 12 has a rectangular parallelepiped shape, it may have a cubic, cylindrical, or spherical shape that can accommodate the furnace body 12 .

Further, in the binder removal furnaces 10 and 110 of the above-described embodiments, the heaters H are provided on the upper wall 16b, the bottom wall 16a, the side walls 16c, 16d, 16e, and 16f, that is, on the six surfaces inside the furnace body 12. However, heaters H may be provided on part of these six surfaces. In this case, the heaters H are preferably provided on two of the six surfaces facing each other.

Further, the inert gas supply pipe 18 of the above-described embodiment introduces the inert gas G into the furnace main body 12 as a diluent gas for the binder. can be anything. In this case, the inert gas supply pipe 18 functions as a gas supply pipe for introducing the atmosphere.

It should be noted that what has been described above is merely an embodiment of the present invention, and the present invention can be modified in various ways without departing from the gist of the present invention.

10, 110: Binder removal furnace 12: Furnace body 14: Outer wall (cooling jacket)
14a: Lower outer wall 14b: Upper outer wall 14c to 14f: Lateral outer wall 16: Furnace wall 16a: Bottom wall 16b: Upper wall 16c to 16f: Side wall 18: Inert gas supply pipe (gas supply pipe)
20: Degassing hole 22: Exhaust pipe 26: On-off valve 28: Tar drain pipe F: Gas flow path H: Heaters Ea to Ef: Gap S1, S2: Inclined surface

Claims (6)

A furnace wall having a top wall, a bottom wall, and four side walls connecting the top wall and the bottom wall to form a heating space, and a heater for heating an object to be heated accommodated in the heating space. and four side walls that connect the upper wall, the bottom wall, and the upper wall and the bottom wall of the furnace wall with a predetermined gap, and are opposed to each other with a predetermined gap, A debindering furnace comprising an upper outer wall portion and an outer wall configured from four horizontal outer wall portions for accommodating the furnace main body,
a gas supply pipe for introducing gas into the furnace body;
provided to pass through the furnace wall, and evaporate the binder volatilized from the gas and the object to be heated in the furnace body into the space between the bottom wall of the furnace wall and the lower outer wall portion of the outer wall. a degassing hole leading to
an exhaust pipe provided through the upper outer wall portion of the outer wall;
a cooling jacket provided so as to face at least a part of the furnace wall via a gas flow path from the degassing hole to the exhaust pipe; are arranged to face each other across the gas flow path from the degassing hole to the exhaust pipe with the same gap,
The gas supply pipes are at least a pair of gas supply pipes for injecting the gas to face each other, and one of the pair of gas supply pipes is one of the pair of side walls facing each other among the four side walls. The other of the pair of gas supply pipes is provided in a state of penetrating only the upper portion, and the other of the pair of gas supply pipes is provided in a state of penetrating only the upper portion of the other of the pair of side walls facing each other out of the four side walls,
The degassing holes are provided through the bottom wall in a number larger than that of the at least one pair of gas supply pipes, and have a flow cross-sectional area larger than the flow cross-sectional area of the gas supply pipes, The gas and the binder volatilized from the object to be heated are led to the space between the bottom wall and the lower wall facing the bottom wall at a flow rate lower than the introduction speed of the degassing holes. and a binder removal furnace. 2. The binder removal furnace according to claim 1, wherein the heaters are provided on the top wall, the bottom wall, and the four side walls, respectively. 3. The debindering furnace according to claim 1, wherein the lower outer wall facing the bottom wall is provided with a tar drain pipe with an on-off valve for discharging the tar accumulated in the lower outer wall. 4. The binder removal furnace according to claim 3, wherein the lower outer wall portion is provided with an inclined surface that becomes lower toward the tar drain pipe. The exhaust pipe is provided through an upper outer wall portion of the outer wall located above the furnace body,
5. The binder removal furnace according to any one of claims 1 to 4, wherein the upper outer wall portion is provided with an inclined surface that becomes higher toward the exhaust pipe. When the binder removal process for the object to be heated is completed, the furnace body performs the sintering process for the object to be heated while the object to be heated is positioned in the furnace body following the binder removal process. The binder removal furnace according to any one of claims 1 to 5, characterized in that it is a

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