JP4167309B2 - Graphite crucible - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a graphite crucible for melting a metal such as aluminum, and more particularly to improvement of the structure.
[0002]
[Prior art]
FIG. 1 is a side sectional view of a crucible furnace in which a graphite crucible 1 is set. A gantry 11 is arranged on the central floor 9 of the combustion chamber 7 of the furnace body 3 made of refractory, and the graphite crucible 1 is placed thereon. There is a burner port 15 at the bottom of the side wall portion 13 of the furnace body 3. In heating the graphite crucible 1, a flame 19 is injected from the burner 17 installed there toward the combustion chamber 7. When the tip of the flame directly hits the graphite crucible 1, the portion is locally heated to undergo oxidation, which is subject to thermal shock and consequently shortens the life of the crucible. It is adjusted so that it is injected toward the side. Combustion gas accompanying the flame rises from the bottom surface of the graphite crucible 1 so as to wrap around the side surface and is discharged from the flue, whereby the furnace temperature rises smoothly and the melt in the crucible is uniformly dissolved. It has become.
[0003]
A solid cylindrical or hollow cylindrical shape having a height dimension of 50 mm to 350 mm and an outer diameter dimension of 200 mm to 400 mm is used for the gantry 11. If the outer diameter of the upper surface of the crucible is smaller than the outer diameter of the bottom surface of the crucible, a large pressure is applied to the contact surface, causing cracks and reducing the life of the crucible 1 and the crucible 11. On the contrary, if the outer diameter of the upper surface of the table is larger than the outer diameter of the bottom surface of the crucible, the presence of the table 11 disturbs the flow of flame and combustion gas, resulting in non-uniform melting. For this reason, normally, the outer diameter of the bottom surface of the crucible is matched with the outer diameter of the bottom surface of the crucible.
[0004]
The crucible 11 and the graphite crucible 1 are carried into the furnace from the opening above the crucible furnace 3, and after placing the crucible 11 in the furnace, the graphite crucible 1 is placed thereon. If the crucible 1 is small and light, the lip is held and suspended, and if the crucible 1 is large and heavy, it is suspended using an unloading machine such as a crucible or toggle.
[0005]
If the separation A between the outer surface of the crucible 1 and the inner wall of the furnace body 3 varies depending on the location, heat to the crucible 1 is not uniformly transferred and melting becomes uneven. Therefore, when placing the crucible 1 on the rack 11, the unevenness of the surface of the rack 11 is confirmed, and the position of the rack 11 is adjusted so that the surface of the rack 11 is horizontal, and the separation A becomes uniform. In this way, the position of the crucible 1 is adjusted. Further, if the center axis of the crucible 1 and the center axis of the crucible 11 are not substantially coaxial, stress distortion may occur in the crucible 1. Therefore, the positions of the crucible 1 and the crucible 11 are adjusted well in consideration of this point. To do.
[0006]
The material constituting the crucible 1 often contains glass in order to prevent oxidation, and when this flows out of the surface by heating, the crucible bottom and the crucible 11 are welded. Therefore, the fireproof fiber sheet 20 may be interposed between the crucible 1 and the cradle 11. In this case, the refractory fiber sheet 20 also functions to stabilize the contact surfaces of the two.
[0007]
[Problems to be solved by the invention]
By the way, the conventional steel table and graphite crucible have the following problems (1) to (5).
[0008]
(1) Problems when transporting the racks The conventional racks are slippery on the surface and do not catch fingers, making it difficult to carry them into a narrow furnace or to align them.
[0009]
(2) Problems related to the adjustment work of the graphite crucible and the crucible The positional relationship between the crucible and the crucible in the furnace is not visible from the outside of the furnace, and the crucible is heavy, so the surface of the crucible is horizontal. It is very troublesome to keep the center axis of the steel plate and the crucible coincident with each other.
[0010]
(3) Problems at the time of exchanging the crucible When exchanging the graphite crucible, the crucible welded to the crucible is lifted together with the crucible, and this may fall during the lifting.
[0011]
(4) Problems in crucible and crucible life judgment Generally, the service life of crucibles is longer than that of crucibles, and the crucible replacement time does not always coincide with the crucible replacement time, and the crucible is replaced with a new one. However, it is not uncommon to continue using the lighthouse as it is. For this reason, the life span of the table may not be predicted, and the table may be damaged during use, and the new crucible just placed on the table may be damaged.
[0012]
(5) Problem of heat shielding Since the bottom of the graphite crucible is in contact with the platform, the heat of the flame is not transmitted well, and the temperature rise tends to be delayed compared to the other parts. When a fiber sheet is interposed, the temperature rise at the bottom of the crucible is further delayed.
[0013]
[Means for Solving the Problems]
The graphite crucible according to the first invention is specified by the following items (11) to (17).
(11) It consists of a molded fired product of a refractory material mainly composed of graphite, and includes a container body and a pedestal. (12) The container body is in the form of a bowl-shaped container with an open top (13 ) The pedestal has a solid cylindrical shape and is integrated with the outer surface of the bottom surface of the container body so that its center axis is substantially coaxial with the vertical center axis of the container body (14) The bottom surface is a plane perpendicular to the central axis (15) The pedestal is formed with several horizontal holes penetrating in the horizontal direction (16) The outer diameter of the pedestal is (17) The height of the pedestal is in the range of 15% to 40% of the height of the container body. [0014]
The graphite crucible according to the second invention is specified by the following items (21) to (22).
(21) It consists of a molded fired product of a refractory material mainly composed of graphite, and includes a container main body and a pedestal. (22) The container main body is in the form of a bowl-shaped container with an open top (23 ) The pedestal has a hollow cylindrical shape and is integrated with the outer surface of the bottom surface of the container main body so that its central axis is substantially coaxial with the vertical central axis of the container main body (24) The bottom surface of the pedestal Is a plane orthogonal to the central axis (25) The pedestal is formed with several horizontal holes penetrating the inside and outside of the cylindrical surface (26) The outer diameter of the pedestal The dimension is in the range of 30% to 50% of the maximum outer diameter of the container body (27) The height of the pedestal is in the range of 15% to 40% of the height of the container body [0016]
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 2 and 3 show a graphite crucible 1 for melting aluminum having a precondition for reaching the creation of the present invention (for convenience, the first embodiment and the second embodiment, respectively). A graphite crucible 1 for melting aluminum having a configuration to which the invention is applied is shown (this is a third embodiment).
These graphite crucibles 1 are formed and fired products made of a refractory material mainly composed of graphite. The graphite crucible 1 is integrated with a container main body 21 in the form of a bowl-shaped container having an open top, and a bottom outer surface of the container main body 21. The pedestal portion 23 is formed. The vertical central axis of the container body 21 and the vertical central axis of the pedestal 23 are substantially coaxial, and the bottom surface of the pedestal 23 is a plane orthogonal to the central axis. In addition, the pedestal is designed so that the flame of the burner does not directly hit the crucible 1 and the combustion gas accompanying the flame wraps the side surface portion from the bottom of the graphite crucible 1 so that the temperature of the entire crucible 1 rises smoothly and uniformly. The outer diameter of the portion 23 is set to be in the range of 30% to 50% of the maximum outer diameter of the container body 21 and the height is in the range of 15% to 40% of the height of the container body 21. is doing.
[0017]
In the graphite crucible 1 of the first embodiment shown in FIG. 2, the container main body portion 21 and the pedestal portion 23 are integrally formed and fired. The pedestal portion 23 has a solid cylindrical shape, and this portion functions as a conventional gantry. In this embodiment, since the heat of the pedestal portion 23 is directly transmitted to the bottom surface of the crucible 1, the temperature of the entire crucible 1 can be raised smoothly and uniformly. In addition, the strength of the bottom of the crucible 1 is increased by the thick pedestal 23, and the durability of the crucible 1 is improved.
[0018]
In the graphite crucible 1 of the second embodiment shown in FIG. 3, the pedestal portion 23 has a hollow cylindrical shape. If it does in this way, the heat capacity of a cylindrical part will decrease and the temperature rise of the base part 23 will be accelerated, and the temperature rise of the crucible 1 will be accelerated | stimulated further along with it.
[0019]
In the graphite crucible 1 of the third embodiment shown in FIG. 4, a container main body 21 and a hollow cylindrical pedestal 23 having a closed upper part are formed separately, and these are bonded together by an adhesive. It has become. In adhering, an adhesive mixed with finely divided silicon carbide, finely divided graphite, finely divided zinc, finely divided metal silicon, finely divided frit, and phenol resin is applied to the bottom surface of the graphite crucible 1 main body and the top surface of the pedestal portion 23 to join them together. The part was heated to cure. In this embodiment, the shape of the pedestal portion 23 is not limited to the hollow cylindrical shape, and for example, a solid cylindrical shape as described above may be used. Two vent holes 27 penetrating to the hollow portion are formed in the diameter direction of the pedestal portion 23. Accordingly, during heating, flame and combustion gas enter the hollow portion from the vent hole 27, and the pedestal portion 23 can be quickly heated. The number of ventilation holes 27 may be two or more, and the number can be increased to the extent that the durability of the pedestal portion 23 is not impaired. Further, when the pedestal portion 23 has a solid columnar shape, the same effect as that of the hollow cylindrical shape can be obtained by forming a horizontal hole penetrating the side surface in several places.
[0020]
As described above, in the graphite crucible in the embodiment described above, the crucible itself has a function as a conventional crucible. Therefore, it is not necessary to adjust the positional relationship between the crucible and the crucible as in the prior art, and the separation between the outer surface of the crucible and the inner surface of the crucible furnace is kept uniform while visually observing from the upper opening of the crucible furnace. Thus, the crucible can be arranged at an optimum position simply by being carried into the furnace.
[0021]
Moreover, although the case where it was a solid cylindrical shape and a hollow cylindrical shape was demonstrated as an example as a shape of the base part 23, even if the base part 23 is shapes other than these (for example, prism etc.), this invention is applied easily. Obviously it can be done.
[0022]
【The invention's effect】
The graphite crucible according to the present invention has the following effects because the base part is integrally formed.
[0023]
(1) Separation between the outer surface of the crucible and the inner wall of the crucible furnace without the troublesome work of keeping the surface of the crucible horizontal in a narrow furnace or aligning the center axis of the crucible and the crucible It is possible to arrange the crucible at the optimum position in the furnace simply by ensuring that is uniform.
[0024]
(2) The cradle welded to the crucible is lifted together with the crucible and does not fall during the lifting.
[0025]
(3) It is not possible to replace only the crucible or only the crucible separately, and the crucible will not be damaged due to failure to predict the life of the crucible as in the prior art.
[0026]
(4) Heat from the pedestal can be efficiently transmitted to the bottom of the crucible, and further, if a horizontal hole penetrating the pedestal is formed, the temperature rise of the pedestal can be accelerated and the bottom of the crucible can be quickly raised. .
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a configuration of a typical crucible furnace.
FIG. 2 is a longitudinal sectional view of a graphite crucible according to a first embodiment of the present invention.
FIG. 3 is a longitudinal sectional view of a graphite crucible according to a second embodiment of the present invention.
FIG. 4 is a longitudinal sectional view of a graphite crucible according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Graphite crucible 3 Furnace main body 7 Combustion chamber 11 Stand 20 Fire-resistant fiber sheet 21 Container body part 23 Base part 27 Vent hole

Claims (2)

A graphite crucible specified by the following items (11) to (17).
(11) It consists of a molded fired product of a refractory material mainly composed of graphite, and includes a container body and a pedestal. (12) The container body is in the form of a bowl-shaped container with an open top (13 ) The pedestal has a solid cylindrical shape and is integrated with the outer surface of the bottom surface of the container body so that its center axis is substantially coaxial with the vertical center axis of the container body (14) The bottom surface is a plane perpendicular to the central axis (15) The pedestal is formed with several horizontal holes penetrating in the horizontal direction (16) The outer diameter of the pedestal is (17) The height of the pedestal is in the range of 15% to 40% of the height of the container body. thing A graphite crucible specified by the following items (21) to (27).
(21) It consists of a molded fired product of a refractory material mainly composed of graphite, and includes a container main body and a pedestal. (22) The container main body is in the form of a bowl-shaped container with an open top (23 ) The pedestal has a hollow cylindrical shape and is integrated with the outer surface of the bottom surface of the container main body so that its central axis is substantially coaxial with the vertical central axis of the container main body (24) The bottom surface of the pedestal Is a plane orthogonal to the central axis (25) The pedestal is formed with several horizontal holes penetrating the inside and outside of the cylindrical surface (26) The outer diameter of the pedestal The dimension is in the range of 30% to 50% of the maximum outer diameter of the container body (27) The height of the pedestal is in the range of 15% to 40% of the height of the container body What is in

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