JPH0686984B2 - Crucible furnace - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a crucible furnace for melting non-ferrous metals such as copper alloys using a crucible.

BACKGROUND ART FIG. 7 is a sectional view of a typical prior art crucible furnace 1. A burner 4 is provided which blows a flame into the combustion chamber 3 in the furnace body 2 and burns the flame in the combustion chamber 3. In the combustion chamber 3, a crucible 5 for arranging a molten alloy such as copper alloy is stored. A lid 7 having an opening 6 is mounted right above the crucible 5. An ingot 8 such as a copper alloy is inserted into the crucible 5 through the opening 6 and heated to obtain a molten metal.

Problems to be Solved by the Invention In such a prior art, since the burner 4 is provided in the lower portion of the furnace body 2, uneven temperature distribution in the combustion chamber 3 occurs,
In the crucible 5, there was a large temperature difference between the upper part and the lower part, and it was difficult to improve the temperature of the molten metal 5a in the crucible 5.

Another problem with this prior art is that since the burner 4 is provided in the lower part of the furnace body 2, the flame and high temperature exhaust gas that are ejected from the burner 4 into the combustion chamber 3 are immediately discharged from the opening 6. Therefore, the residence time of these in the combustion chamber 3 is short, and it is difficult to improve the thermal efficiency.

The third problem of this prior art is that when the crucible 5 is damaged, the molten metal stored in the crucible 5 spills,
There was a problem that so-called spillage of hot water occurred and flowed over the hearth 2a of the furnace body 2 and clogged the burner 4.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a crucible furnace which can be downsized and whose thermal efficiency can be remarkably improved.

Means for Solving the Problems The present invention is directed to a furnace body having a storage space having an opening opened upward, a crucible arranged in the storage space, and a crucible spaced apart radially outward of the crucible. Surround the
A cylinder having a space between it and the inner wall of the furnace body forming the storage space, the upper end of which is substantially level with the upper end of the crucible, and the lower end of which has a communication hole penetrating in the thickness direction. -Shaped partition wall, a closing member shaped to close the upper end of the crucible and the upper end of the tubular partition, and a burner arranged below the closing member between the upper end of the crucible and the upper end of the tubular partition. The crucible furnace is characterized in that the cylindrical partition wall and the inner wall forming the housing space of the furnace body communicate with the opening.

A preferred embodiment of the present invention is characterized by comprising a removable preheating cylinder that surrounds the opening and is continuous with the opening.

Another preferred embodiment of the present invention is a coating layer made of a refractory material, the surface of which is non-leakable with respect to the molten metal, and the fluidity of the molten metal is good, on the hearth forming the housing space of the furnace body. Is arranged.

In still another preferred embodiment of the present invention, the closing member has an annular recess that is open upward, at least the inner peripheral surface of the recess is non-leakable to the molten metal, and the flowability of the molten metal is good. It is characterized in that it is made of a refractory material.

Yet another preferred embodiment of the present invention is characterized in that the tubular partition wall is made of a material having a heat storage property.

A further preferred embodiment of the invention is characterized in that the furnace body consists of lightweight insulation.

Function The crucible furnace according to the present invention has the crucible arranged in the storage space in the furnace body, and the partition wall is provided radially outward of the crucible and at the same time with the inner wall of the furnace body. The upper end of this cylindrical partition is substantially level with the upper end of the crucible, and a communication hole penetrating in the thickness direction is formed at the lower end. Further, a closing member having a shape for closing the upper end of the crucible and the upper end of the cylindrical partition is provided. The burner is arranged below the closing member between the upper end of the crucible and the upper end of the tubular partition. Further, a space between the partition wall and an inner wall forming a housing space for the furnace body is communicated with an opening opened above the furnace body.

Since the crucible furnace is configured as described above, the flame and the exhaust gas ejected from the burner are ejected between the crucible and the cylindrical partition wall and below the closing member. The jetted flame and exhaust gas move downward between the crucible and the cylindrical partition wall, move radially outward through the communication hole of the cylindrical partition wall, and move between the cylindrical partition wall and the inner peripheral surface of the furnace. Ascends and is discharged from the opening of the furnace body. Therefore, such flames and high-temperature exhaust gas stay in the crucible furnace for a longer time, and the thermal efficiency is significantly improved. Further, since the burner is provided in the upper part of the storage space, the temperature distribution of the crucible is made uniform, and the temperature of the upper part of the molten metal in the crucible can be increased. Therefore, the dissolution rate of the material to be dissolved is improved, and the extent to which the exhaust gas or the like is absorbed in the molten metal can be reduced.

Further, since the burner is provided above the storage space, even if the molten metal flows out due to damage to the crucible, the burner will not be blocked.

Example FIG. 1 is a vertical sectional view of a crucible furnace 11 according to an embodiment of the present invention, FIG. 2 is a sectional view taken along section line II-II of FIG. 1, and FIG. 2 is a partial sectional view taken along the section line III-III in FIG. 2, and FIG. 4 is a sectional view taken along the section line IV-IV in FIG. The configuration of the crucible furnace 11 of the present embodiment will be described with reference to FIGS. 1 to 4. A storage space 13 is formed in the furnace body 12 of the crucible furnace 11, and a loading table 15 is arranged on the hearth 14 near the center of the storage space 13. A crucible 16 is mounted on the mounting table 15. Within the storage space 13, there is a gap having a predetermined length from the inner wall 17 of the furnace body 12, and a position having a predetermined gap from the crucible 16,
A cylindrical partition 18 (hereinafter, abbreviated as partition 18) is arranged. Partition
18 is made of a material having heat storage property and fire resistance.

Further, the hearth 14 includes a floor member 19 having excellent heat resistance and a floor member 19
And a coating layer 20 disposed on the top. The floor member 19 has a structure in which fibrous ceramics are compressed, has excellent fire resistance, good heat insulation, and has a small specific gravity and a small amount of heat storage. With such a material, the side wall of the furnace body 12
21 is also formed. Therefore, by providing such a furnace body 12, the heat storage amount of the entire crucible furnace 11 can be reduced, and an energy saving effect can be achieved.

The coating layer 20 has excellent fire resistance, excellent thermal shock resistance against rapid heating and quenching, and is made of a material having extremely low thermal conductivity. An example of such a material is known as “Cryston” (trade name) manufactured by Nippon Insulators Co., Ltd.
%, SiO ₂ 3.0%, Fe ₂ O ₃ 0.4% and Si ₃ N ₄ and Si ₂ ON ₂
It is a silicon carbide refractory material having a composition in which the sum of

A furnace lid 23 having an opening 22 is mounted on the furnace body 12. The inner diameter D1 of the opening 22 is formed smaller than the inner diameter D2 of the furnace body 12. A preheating cylinder 24 having an inner diameter substantially the same as that of the opening 22 is mounted on the furnace lid 22. At this time, a gap having a predetermined length is provided between the lower surface of the furnace lid 23 and the upper end of the crucible 16. Further, on the partition wall 18, a closing member 25 that is annular and has an annular recess 33 formed over the entire circumference is mounted. The upper end of the closure member 25 is configured to be substantially level with the upper end of the crucible 16, and the radially inner end of the closure member 25 is
As close as possible to the outer peripheral surface of the crucible 6, the crucible 16 and the partition wall 18
The upper part of the combustion chamber 26 formed by the above is closed as much as possible. An annular cover member 27 is mounted on the furnace body 12.

The outer peripheral surface of the closing member 25 in the radial direction is configured to have substantially the same peripheral surface as the outer peripheral surface of the partition wall 18, and has a predetermined length between the outer peripheral surface and the inner peripheral surface of the cover member 27. Configured to have a gap of.

A plurality of (six in this embodiment) communication holes 28a to 28f (generally denoted by 28) penetrating in the thickness direction are formed at the lower end of the partition wall 18 at intervals in the circumferential direction. To be done. At the lower part of the side wall 21 of the furnace body 12, a take-out port 29 communicating with the storage space 13 and extending in the radial direction is formed.

FIG. 5 is a perspective view of the partition wall 18. The partition wall 18 is formed by stacking right-cylindrical partition wall members 30a, 30b, 30c having the same shape so as to be coaxial with each other. Partition member 30a
The communication holes 28a, 28b, ..., 28f as described above are formed in the.

FIG. 6 is a perspective view of a part of the closing member 25. Closure member
The height h1 of the outer peripheral wall 31 of 25 is configured to be larger than the height h2 of the inner peripheral wall 32. The annular recess 33 of the closing member 25 is opened upward. The closing member 25 is the covering layer 20 of the hearth 14 described above.
It is formed from the same material as.

A burner 34 is provided below the closing member 25 between the crucible 16 and the partition wall 18. Burner 34 is configured to eject a flame tangentially into combustion chamber 26. Further, the installation position is arranged in the crucible 16 so as to be higher than the molten metal surface 35.

The operation of the crucible furnace 11 of this embodiment will be described with reference to FIG. In melting the non-ferrous alloy ingot 36 such as a copper alloy, the preheating cylinder 24 is mounted on the furnace lid 23, the ingot 36 is inserted from the opening 22, and the lid 38 having the opening 39 is mounted. . Thus, the flame and the exhaust gas ejected from the burner 34 heat the crucible 16 and descend while swirling in the combustion chamber 26, and as shown by the arrow A1 from the communication hole 28 of the partition wall 18, outward in the radial direction. It moves and rises in the exhaust gas passage 37 between the partition wall 18 and the furnace body 12, passes through the gap between the cover member 27, the furnace lid 23, and the closing member 25 as shown by the arrow A2, and opens. It is discharged from the opening 22 through the preheating cylinder 24 into the atmosphere through the opening 39. The exhaust gas preheats the ingot 36 inserted through the opening 22. The preheating cylinder 24 guides the exhaust gas and the flame from the opening 22 upward, thereby allowing the ingot 36 to be efficiently heated.

The ingot 36 to be melted removes the preheating cylinder 24 after reaching the lower part of the opening 22 as the melting progresses.
A lid 38 is mounted on the furnace lid 23 to prevent the flame and the exhaust gas in the storage space 13 from being unnecessarily discharged from the opening 22 and lowering the thermal efficiency. As the dissolution of Ingot 36 progresses,
The amount of combustion by the burner 34 may be reduced to prevent an increase in exhaust gas loss, thereby saving energy. The preheating cylinder 24 and the lid 38 lower the temperature of the exhaust gas and improve the surrounding work environment. In this way, the molten metal is obtained in the crucible 16.

In this way, the partition wall 18 is provided in the storage space 13 in the furnace body 12, and the flame and the exhaust gas are allowed to flow in the directions indicated by the arrows A1 and A2 as described above. The residence time in the storage space 13 becomes longer, and the crucible 16 can be efficiently heated.

Further, such a partition 18 is provided, and the burner 34 is arranged between the partition 18 and the crucible 16. Therefore, storage space
The combustion noise in 13 is doubly absorbed by the partition wall 18 and the side wall 21 made of glass fiber, and the combustion noise transmitted to the outside of the crucible furnace 11 can be significantly reduced.

In the present embodiment, the burner 34 is provided in the upper part of the storage space 13, and the flames and exhaust gas ejected are swirled and lowered in the combustion chamber 26 to heat the crucible 16. Therefore, the temperature distribution in the storage space 13 is made uniform, the temperature of the upper portion of the molten metal in the crucible 16 is raised, and the melting speed of the ingot 36 is improved. Therefore, the degree of absorption of gas such as exhaust gas into the molten metal can be reduced.

Further, since the partition wall 18 is provided in the storage space 13, the temperature distribution in the storage space 13 is made uniform as described above, and as described in the prior art, the crucible is locally heated and the crucible is damaged. Can be prevented.

The upper column of the crucible 16 is made of a material having excellent heat resistance, and the gap between the outer peripheral surface of the crucible 16 and the inner peripheral surface of the partition wall 18 is, for example, 10
Since it is set to an appropriate interval of about 0 mm to prevent damage to the crucible 16 due to the flame from the burner 34 as much as possible, it corresponds to the loading table 9 in the prior art described with reference to FIG. 7. It is possible to reduce the height of the loading table 15 of this embodiment. In the prior art, the crucible 5 (see FIG. 7) is made of a material having a relatively low heat resistance, and in order to prevent damage to the crucible 5, the tall platform 9 is used. The structure of the furnace 1 was enlarged.

Since the partition wall 18 has a heat storage amount, after extinguishing the burner 34,
It is possible to prevent the hot water temperature from rapidly decreasing, and to lengthen the time required for the molten metal pumping work.

In the above-described embodiment, the loading platform 15 is in operation of the crucible furnace 11 to prevent the crucible 16 from adhering to the coating layer 20 of the hearth 14 due to the vitreous substance precipitated from the crucible 16. It suffices to use a mounting table 15 that is sufficiently low so as to achieve the function of, and thus the configuration can be downsized. The height of the mounting table 15 may be less than 50 mm, for example.

Also, since the burner 34 is installed above the storage space 13, the crucible
Even when 16 is damaged and the molten metal inside flows out, the burner 34 is not blocked.

Even if the melt of the ingot 36 is completed and the molten metal is spilled out when the molten metal is pumped out, the closing member 25 having the annular recess 33 is provided in the crucible 16
Since it is provided over the outer periphery of the molten metal, it is possible to prevent the molten metal from dropping to the hearth 14. Further, the closing member 25,
As described above, since the molten metal has good fluidity and is formed of a material that has a good so-called melt-out,
The molten metal in 25 or an alloy in which the molten metal is solidified can also be easily taken out. Further, even if the molten metal that spills over falls on the hearth 14, the coating layer 20 is formed of the same material as the closing member 25. Therefore, the molten metal that has fallen or an alloy in which the molten metal solidifies can easily You can take it out from 14.

As described above, since the partition wall 18 is configured by stacking the partition wall members 30 in, for example, three stages, the partition wall 18 can be easily taken out even during maintenance work of the crucible furnace 11.
Maintenance work for the entire crucible furnace 11 can be easily performed.

In configuring the partition wall 18 in the above-described embodiment,
The number of partition members 30 to be stacked is not limited to three. Further, what is melted is not limited to the ingot 36, but may be a return material or the like.

Effects As described above, according to the present invention, a storage space having an opening opened upward is formed in the furnace body. Also, place a crucible in the storage space. The crucible is surrounded by a radial outer space with a space between the crucible and the inner wall of the furnace body.The upper end is almost the same height as the upper end of the crucible, and the lower end is A cylindrical partition having a communication hole penetrating in the thickness direction was arranged. Further, an annular closing member that closes the upper end of the crucible and the upper end of the tubular partition is provided, and the burner is arranged below the closing member between the upper end of the crucible and the upper end of the tubular partition. The opening between the cylindrical partition wall and the inner wall of the furnace body is communicated.

By arranging such a cylindrical partition wall in the storage space, the flame and the exhaust gas from the burner can be retained for a long time between the cylindrical partition wall and the crucible, and the heat of the flame and the exhaust gas can be reduced. Thus, the crucible can be efficiently heated. Therefore, the so-called energy saving effect can be remarkably improved.

Further, by disposing the burner in the upper part of the storage space and allowing the flame and the exhaust gas ejected from the burner to flow downward, the temperature distribution in the storage space can be made uniform. Therefore, the molten metal in the crucible is also heated uniformly, and the problem pointed out in the prior art that it is difficult to improve the temperature of the upper portion of the molten metal is solved. Further, by improving the temperature distribution as described above, the dissolution rate is improved, and the degree of absorption of the exhaust gas into the molten metal can be significantly reduced.

In addition, by installing the burner at the top of the storage space,
Even if the crucible is damaged and the molten metal flows out, it is possible to prevent the burner from being blocked.

[Brief description of drawings]

1 is a longitudinal sectional view of a crucible furnace 11 according to an embodiment of the present invention, FIG. 2 is a sectional view taken along section line II-II of FIG. 1, and FIG. 3 is section line III of FIG. -III is a partial cross-sectional view as seen from FIG. 4, FIG. 4 is a cross-sectional view as seen from the section line IV-IV in FIG. 1, FIG. 5 is a perspective view of the cylindrical partition wall 18, and FIG. FIG. 7 is a partial perspective view, and FIG. 7 is a vertical sectional view of a crucible furnace 1 of the prior art. 11 …… crucible furnace, 12 …… furnace body, 13 …… storage space, 16 ……
Crucible, 18 …… cylindrical partition, 22 …… opening, 23 …… furnace lid, 24
...... Preheating cylinder, 25 …… Closing member, 28 …… Communication hole, 30 …… Ball member, 33 …… annular recess, 34 …… Burner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroshi Yamamoto, 5-1, Hirano-cho, Higashi-ku, Osaka, Osaka Prefecture, Osaka, Osaka Gas Co., Ltd. (72) Hisao Yokoyama, 5--1, Hirano-cho, Higashi-ku, Osaka, Osaka (72) Inventor Akira Kinoshita 430-16 Shimomitsubashicho, Yamatokoriyama City, Nara Prefecture

Claims (6)

[Claims] 1. A furnace body having a storage space having an opening opened upward, a crucible arranged in the storage space, and a crucible spaced apart radially outward of the crucible.
A cylinder having a space between it and the inner wall of the furnace body forming the storage space, the upper end of which is substantially level with the upper end of the crucible, and the lower end having a through hole penetrating in the thickness direction. -Shaped partition wall, a closing member shaped to close the upper end of the crucible and the upper end of the tubular partition, and a burner arranged below the closing member between the upper end of the crucible and the upper end of the tubular partition. And a cylindrical partition wall and an inner wall that forms a storage space for the furnace body communicate with the opening. 2. A crucible furnace according to claim 1, further comprising a removable preheating cylinder surrounding and surrounding the opening. 3. A hearth forming a storage space for the furnace body,
The crucible furnace according to claim 1, characterized in that a coating layer made of a refractory material, the surface of which is non-leakable with respect to the molten metal and the fluidity of the molten metal is good, is arranged. 4. The closure member has an annular recess that is open upward, and at least the inner peripheral surface of the recess is made of a refractory material that is non-leakable with respect to the molten metal and has good fluidity of the molten metal. The crucible furnace according to claim 1, characterized in that 5. The crucible furnace according to claim 1, wherein the cylindrical partition wall is made of a material having a heat storage property. 6. The crucible furnace according to claim 1, wherein the furnace body is made of a lightweight heat insulating material.