JP2002181460A - Crucible furnace with movable preheat tower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fresh crucible furnace to have comparatively simple structure suited for a batch type crucible furnace, improve the working efficiency of the crucible, and further, be effectively to saving of energy and improvement of work environment. SOLUTION: A crucible furnace with a movable preheat tower is featured that a movable preheat tower is suited above a crucible furnace body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crucible furnace with a movable preheating tower used for melting metals such as aluminum and copper alloys, and more particularly, to a labor-saving and energy-saving productivity in which a preheating effect of a raw metal is enhanced. Related to the excellent crucible furnace.

[0002]

2. Description of the Related Art A crucible furnace is a furnace in which a raw metal is put in a crucible and melted using a fuel such as heavy oil or gas.
FIG. 1 is a front sectional view of an example of a conventional crucible furnace. The crucible furnace 1 includes a crucible table 4 placed on an installation surface of a combustion chamber 3.
A crucible (graphite crucible) 2 is placed in a furnace, a combustion burner 5 is mounted in a hole penetrating a peripheral wall made of a refractory material 6, and the temperature of the crucible 2 is raised by blowing a flame into a combustion chamber. The flame is swirled from the bottom to the top of the crucible from the bottom to the top through an opening (or pumping port) 8 of the furnace lid 7 or an exhaust port such as a flue (not shown) attached to the side of the steel case 9. It is emitted to the outside as exhaust gas.

[0003] The crucible furnace having such a structure has the advantage that the combustion gas does not directly hit the ingot, and has the advantage that it can be accurately compounded. Used in the manufacture of The melting operation using a crucible furnace is generally performed as a discontinuous batch operation, and the input of the raw metal and the extraction of the molten metal are mainly performed manually. The molten metal is degassed by a flux treatment or the like, and then is pumped out.
In the case of a stationary crucible furnace, pumping is performed using a pumping crucible or a ladle, and in the case of a tiltable crucible furnace, a crucible furnace is inclined to receive a hot water using a ladle or the like.

[0004] The capacity of the crucible is determined by the amount of metal to be melted. However, the raw metal is often bulky, and if the volume of the raw metal is greatly reduced due to melting, the raw metal is fed in several times. Need to be done.

For this reason, a so-called intermediate crucible has been used in which a crucible having the same diameter is added to the crucible to increase the capacity of the crucible. In the relay crucible, the raised portion is used by being bonded to the upper edge of the crucible using refractory cement, but in this case, the distance to the molten metal surface is deep, and it is inconvenient to pump out.

In addition, when the raw metal is an aluminum casting or the like, the volume of the aluminum casting is greatly reduced during melting due to its bulkiness. Therefore, even if a relay crucible is used, a one-charge molten metal (a molten metal for one full crucible) can be obtained. It is difficult to secure the amount of dissolution in one charge, and it is often necessary to additionally charge the solution once or twice.

[0007] Accordingly, the melting time becomes longer, the charging operation increases accordingly, and the combustion gas is exhausted from the furnace lid, so that the operator is exposed to high-temperature hot air, which poses a problem as a working environment. If the transportation of heavy raw materials and the proximity to exhaust gas can be reduced even once, it will lead to a great improvement in work.

Further, in the conventional crucible furnace, since the exhaust gas is directly discharged to the outside at a high temperature from the exhaust port, the melting heat efficiency is low as compared with other furnaces, and the indoor crucible furnace is installed. Because hot exhaust gas deteriorates the environment,
There are energy conservation and environmental health issues.

Japanese Patent Application Laid-Open No. Hei 1-210794 describes a method of preheating a raw metal and charging it into a crucible furnace. In the crucible furnace used in this method, a melting furnace is provided above the crucible furnace, the raw material metal is heated and melted in the melting furnace, the melt enters the lower crucible furnace, and the exhaust gas from the crucible furnace is discharged from the flue. It has a structure that enters the melting furnace. If the raw metal is preheated using a crucible furnace with such a structure, the charging work, the working environment,
It is thought to contribute to energy saving and other improvements. However, it can be said that the crucible furnace equipped with the melting furnace described above can be used in a large-scale factory that continuously melts raw metal and performs casting like die casting, but it is not suitable for a batch type casting factory. It is.

[0010]

SUMMARY OF THE INVENTION The main object of the present invention is to:
An object of the present invention is to provide a novel crucible furnace which has a relatively simple structure suitable for a batch type crucible furnace, can improve the working efficiency of the crucible furnace, and is effective for energy saving and improvement of a working environment.

[0011]

Means for Solving the Problems The present inventor has conducted intensive studies in view of the above-mentioned problems, and as a result, by installing a movable preheating tower above a conventional crucible body, a batch-type preheating tower has been developed. By using a relatively simple apparatus suitable for a crucible furnace, the exhaust gas of the crucible furnace can be effectively used, and it has been found that the above-mentioned problems can be solved, and the present invention has been completed. That is, the present invention provides the following crucible furnace with a movable preheating tower. 1. A crucible furnace with a movable preheating tower, wherein a movable preheating tower is provided above the crucible furnace body. 2. The preheating tower
A structure in which a heat insulating material is arranged inside the cylindrical container, and has an inner diameter smaller than the inner diameter of the furnace lid opening. During melting, the lower opening of the cylindrical container is positioned at the position of the furnace lid opening. Item 2. The crucible furnace according to the above item 1, wherein the crucible furnace can be installed so as to coincide with the above, and can be moved from the opening of the furnace lid except during the melting operation.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a front sectional view showing a conventional crucible furnace, and FIG. 2 is a front sectional view showing an example of a crucible furnace with a movable preheating tower according to the present invention.

In the crucible furnace of the present invention shown in FIG. 2, a preheating tower 10 is installed above a crucible 2 of a conventional crucible furnace. The crucible 2 used for the crucible furnace may be the same as a conventional crucible, and for example, a crucible containing graphite, silicon carbide or the like as a main component, a cast iron crucible, or the like can be used.

The preheating tower 10 is, for example, a cylindrical vessel 1
Insulation material is placed inside 1 and stainless steel plate 1 is placed inside
9 is lined. During the melting operation, the preheating tower is configured such that the opening at the bottom of the cylindrical container is connected to the opening 8 of the furnace lid 7.
Install so that it matches the position of. Here, as the cylindrical container, a metal case such as iron or stainless steel is usually used. The heat insulating material is not particularly limited. For example, a block of ceramic wool (fire resistant fiber; kao wool, ibi wool, etc.) is cut out,
What is necessary is just to adhere | attach between a metal case and stainless steel lining using fire-resistant mortar etc. which use sodium silicate as a binder. In this case, since the ceramic wool is lightweight, there is an advantage that the movement of the preheating tower is easy. Alternatively, a heat-insulating castable refractory may be poured between the metal case and the stainless steel lining.

The lining made of the stainless steel plate 19 is installed in order to prevent breakage of the heat insulating material 11 when the material to be melted 14 is charged. For example, SUS304 is used as a material having sufficient heat resistance. Etc. can be used. The stainless steel plate is more stable in heat resistance and acid resistance than iron, and the thermal expansion of this portion is absorbed by the heat insulating material, so that there is no problem in use. However, when the copper alloy is melted, since the waste heat temperature is high, the lining of the preheating tower is preferably made of only a heat-insulating castable refractory.

The inner diameter of the preheating tower 10 is preferably smaller than the inner diameter of the opening 8 of the furnace lid 7. If the inner diameter of the preheating tower is larger than the inner diameter of the opening 8 of the furnace lid 7, the material to be melted 14 rides on the furnace lid 7 and the material to be melted hardly falls down, and a shelf hanging phenomenon occurs. is there. The inner diameter of the opening of the crucible 2 is usually larger than the inner diameter of the opening 8 of the furnace lid 7.

The interior of the cylindrical vessel of the preheating tower 10 is preferably vertically or slightly widened downward. With the inside of the preheating tower 10 having such a shape, the material to be melted 14 can be easily lowered. Therefore, a receiving member for receiving the raw material as seen in the preheating tower of the melting furnace becomes unnecessary.

The height of the preheating tower 10 is determined by the capacity of the crucible and the internal volume of the preheating tower plus the internal volume of the crucible. From the viewpoint of handling, the height is preferably about 1000 mm or less.

The preheating tower 10 can be installed such that the lower opening of the cylindrical container 11 coincides with the position of the upper opening of the crucible 2 during the melting operation. At the time of filling of the material to be melted or at the time of a flux treatment or a pumping treatment after the completion of the melting operation, a structure capable of moving from the opening of the crucible 2 is adopted. For example, the preheating tower 10
The wheels 13 for moving the preheating tower may be attached to the side wall of the cylindrical container (steel case) 11 so that the structure can be easily moved by traveling on the work base 16. Instead of mounting the wheels 13, the preheating tower may be movable using other moving means, for example, a crane.

The shape of the upper part of the cylindrical container (steel case) 11 of the preheating tower 10 is not particularly limited, but usually a cover (damper) 18 provided with an exhaust port at the center.
And a structure that can be opened and closed as needed.

The melting operation using the crucible furnace of the present invention can be performed, for example, in the following steps. (1) The material to be melted 14 is weighed to make one batch. (2) A part of the material to be melted 14 is put up to the top of the crucible 2 into the crucible 2 having the remaining hot water 15 at the bottom or at the bottom. (3) The preheating tower on the rail 17 of the cradle 16 of the crucible furnace is run, and is moved directly above the crucible. (4) The damper 18 of the preheating tower is opened, and the remaining material to be melted 14 is charged. Then, the damper 18 is closed, the combustion burner 5 is ignited, the crucible 2 is heated, and the material to be melted 14 is melted. (5) After the melting is completed, the preheating tower 10 is run and separated from the crucible furnace. (6) After performing a flux treatment or the like, the molten metal is pumped out from a pumping port 8 at the center of the furnace lid 7.

In the melting treatment using the crucible furnace of the present invention, various metals such as aluminum, copper alloy and zinc can be used as the material to be melted.

[0024]

According to the present invention, the following excellent effects can be achieved by installing a preheating tower having a relatively simple structure. (1) The preheating tower is small and inexpensive, can be easily handled and maintained, and is suitable for a batch type crucible furnace. (2) It is possible to reduce the number of times the raw metal is charged and to melt the raw metal in a short time. As a result, the melting time is shortened, energy and labor are saved, and dangerous work such as scattering of the molten metal when the operator puts the ingot into the molten metal is eliminated. (3) Since the exhaust heat temperature is reduced, it is possible to suppress an increase in the room temperature, thereby improving the working environment. (4) The preheating of the raw metal improves the melting heat efficiency of the crucible furnace. (5) When the raw metal melts down in the preheating tower, deposits of the raw metal such as oil burn, so that even when using the raw metal having such a deposit, a clean molten metal can be obtained. .

[0025]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 An aluminum casting was melted using a crucible furnace having a movable preheating tower having the structure shown in FIG.

As the crucible 2, a graphite crucible is used. As the preheating tower 10, a refractory fiber 12
, And a stainless steel lining 19 was installed on the inside thereof. The opening and closing of the damper 18 was performed by a cylinder.

As a material to be melted, 250 aluminum castings are used.
kg was weighed and a part thereof was put into the crucible 2 up to the top of the crucible. Next, the preheating tower 10 on the rail 17 of the cradle 16 of the crucible furnace was run, and moved immediately above the crucible. After opening the damper 18 of the preheating tower 10 and charging the remaining aluminum casting, the damper 18 was closed, the combustion burner 5 was ignited, and the crucible 2 was heated to melt the aluminum casting. The exhaust gas was discharged from a central exhaust port of the damper 18. 80 minutes after ignition, total amount of aluminum casting 2
Dissolution of 50 kg was completed. This was a result that the melting time could be reduced by about 25 minutes compared to the case of using a conventional crucible furnace without a preheating tower. Fuel gas usage has been saved by 20%. The temperature of the exhaust gas discharged from the exhaust port during melting was measured to be 360 ° C. This is 2 times less than when the preheating tower is not used.
The exhaust gas temperature was 00 ° C. lower.

After the dissolution, the preheating tower was moved. Then, the molten metal was pumped out by deoxidation.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a conventional crucible furnace.

FIG. 2 is a front sectional view of an example of a crucible furnace with a movable preheating tower according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crucible furnace main body 2 Crucible (graphite crucible) 3 Combustion chamber 4 Crucible stand 5 Combustion burner 6 Refractory material 7 Furnace lid 8 Exhaust port, Pumping outlet 9 Iron case of crucible furnace main body 10 Preheating tower 11 Cylindrical container of preheating tower ( 12) Heat insulation material 13 Wheels 14 Material to be melted 15 Hot water 16 Work base 17 Rail 18 Damper 19 Stainless steel lining

Continued on the front page (72) Inventor Tomohiro Hatanaka 1-21-3 Ebisu, Shibuya-ku, Tokyo Inside Japan Crucible Co., Ltd. (72) Inventor Furuzawa 1-21-3 Ebisu, Shibuya-ku, Tokyo Inside Japan Crucible Co., Ltd. (72) Inventor Yasunori Matsuzaki 1-21-3 Ebisu, Shibuya-ku, Tokyo F-term in Crucible Co., Ltd. 4K046 AA04 BA02 CA03 DA01 DA03 4K063 AA04 AA13 BA03 CA01 CA02 GA02

Claims (2)

[Claims] 1. A crucible furnace with a movable preheating tower, wherein a movable preheating tower is provided above the crucible furnace main body. 2. A preheating tower having a structure in which a heat insulating material is arranged inside a cylindrical container, and has an inner diameter smaller than an inner diameter of an opening of a furnace lid. Part can be installed so that it matches the position of the opening of the furnace lid,
2. The crucible furnace according to claim 1, wherein the crucible furnace is movable from an opening of the furnace lid except during the melting operation.