WO2025089336A1 - Impurity removal unit, and molten metal melting furnace, molten metal holding furnace, or molten metal transfer tub provided with impurity removal unit - Google Patents

Abstract

The purpose is to provide an impurity removal unit which makes it possible to prevent molten metal from being contaminated with impurities.　An impurity removal unit 10 is placed on bottom walls 20, 30 which are surrounded by side walls 21, 31 and above which molten metal can move in one direction. The impurity removal unit 10 includes at least two barriers 11 which are spaced apart along the direction of the movement of the molten metal and which block the movement of the molten metal. Among the at least two barriers 11, a barrier 11A which is located on the most upstream side in the direction of the movement of the molten metal has, in a lower portion thereof, a first flow-through hole 12 through which the molten metal passes, and at least another barrier 11B has, in an upper portion thereof, a second flow-through hole 13 through which the molten metal passes.

Description

Impurity removal unit, and molten metal melting furnace, holding furnace, or transfer trough equipped with the impurity removal unit

The present invention relates to an impurity removal unit, and a melting furnace, holding furnace, or transfer trough for molten metal equipped with an impurity removal unit.

For example, a melting and holding furnace is equipped with a melting chamber for melting metals such as aluminum and aluminum alloys, a holding chamber for receiving the molten metal (so-called "molten metal") from the melting chamber and holding it at high temperature, and a pumping chamber for pumping out the molten metal. The holding chamber and pumping chamber are arranged adjacent to each other and are separated by a partition wall, and the molten metal can move from the holding chamber to the pumping chamber through a communication part below the partition wall and above the bottom wall. The molten metal pumped out from the pumping chamber is used for casting, etc.

The molten metal in the holding chamber contains impurities such as oxides and hard spots. If impurities move from the holding chamber to the pumping chamber along with the molten metal, the impurities will be mixed into the molten metal pumped out of the pumping chamber, and if the molten metal containing impurities is used for casting, etc., it will cause a defective product. As such, since the quality of the molten metal has a significant impact on the quality of castings, etc., measures are required to prevent impurities from moving from the holding chamber to the pumping chamber along with the molten metal.

Patent Document 1 discloses a melting and holding furnace in which a step is formed at the connection between the bottom wall of the pumping chamber side and the bottom wall of the holding chamber side below the partition wall, protruding above the bottom wall of the holding chamber side, and a communication section is configured to open above the step. In the melting and holding furnace of Patent Document 1, when the molten metal in the holding chamber moves to the pumping chamber, even if precipitates in the holding chamber move to the pumping chamber along with the molten metal, the movement of the precipitates is stopped at the step between the holding chamber and the pumping chamber, and movement to the pumping chamber is restricted. In this way, the melting and holding furnace of Patent Document 1 prevents impurities from being mixed into the molten metal in the pumping chamber.

JP 2019-109024 A

The impurities present in the holding chamber include sediments that sink and accumulate on the bottom wall, as well as floating matter that floats on the surface of the molten metal. In the melting and holding furnace of Patent Document 1, the movement of sediments in the holding chamber to the pumping chamber can be sufficiently restricted, but the movement of floating matter cannot be sufficiently restricted. For example, when the molten metal in the holding chamber is stirred for flux treatment, floating matter on the surface of the molten metal may move below the partition wall and move from the communication part to the pumping chamber. Or, when the molten metal in the pumping chamber is pumped out, the level of the molten metal in the holding chamber drops, and at this time, floating matter on the surface of the molten metal may move below the partition wall and move from the communication part to the pumping chamber.

As described above, the melting and holding furnace of Patent Document 1 has the problem that it is not possible to sufficiently prevent impurities from being mixed into the molten metal in the pumping chamber. This problem also exists in holding furnaces that do not have a melting chamber.

The present invention has been made with a focus on solving the above problems, and aims to provide an impurity removal unit that can prevent impurities from being mixed into molten metal. The present invention also aims to provide a melting and holding furnace or holding furnace (hereinafter, in this disclosure, melting and holding furnaces are included in holding furnaces and are simply referred to as "holding furnaces") equipped with an impurity removal unit to prevent impurities from being mixed into molten metal in the pumping chamber. The present invention also aims to provide a melting furnace equipped with an impurity removal unit to prevent impurities from being mixed into molten metal flowing out of the melting furnace. The present invention also aims to provide a transfer trough equipped with an impurity removal unit to remove impurities that have been mixed into molten metal delivered from a melting furnace or the like to various supply destinations.

In order to solve the above problems, the present invention focuses on the impurity removal unit described in item 1 below.

Item 1. An impurity removal unit that is surrounded by a side wall and is installed on a bottom wall above which molten metal can move in one direction,
at least two barriers spaced apart along a direction of movement of the molten metal, the at least two barriers blocking the movement of the molten metal;
An impurity removal unit, wherein a first passage hole through which the molten metal passes is formed in the lower part of the barrier located most upstream in the direction of movement of the molten metal among the at least two barriers, and a second passage hole through which the molten metal passes is formed in the upper part of at least one of the other barriers.

The impurity removal unit of the present invention also includes the impurity removal unit described in the following item 2 as a preferred embodiment of the impurity removal unit described in the above item 1.

Item 2. The impurity unit according to item 1,
a base resting on the bottom wall, the at least two barrier walls standing on the base;
a pair of guides extending from the base and sandwiching the at least two barriers from both sides;
an impurity unit, wherein the base, the at least two barriers and the pair of guides are integrated together;

The impurity unit of the present invention also includes the impurity removal unit described in the following item 3 as a preferred embodiment of the impurity removal unit described in the above item 2.

Item 3. The impurity unit according to item 2, in which at least one of the pair of guides and/or the base is formed with an embedded portion for embedding a heater.

The impurity removal unit of the present invention also includes the impurity removal unit described in the following item 4 as a preferred embodiment of the impurity removal unit described in item 2 or 3 above.

Item 4. A degassing device including a gas introduction pipe through which an insoluble gas is introduced and a bubble generator that generates bubbles of the insoluble gas,
Item 4. The impurity unit according to item 2 or 3, wherein the gas inlet pipe extends along one of the pair of guides, and the bubble generator is attached to the base so as to emit bubbles above the base.

In order to solve the above problems, the present invention also focuses on the holding furnace described in item 5 below.

Item 5. A holding furnace including at least a holding chamber for holding molten metal and a pumping chamber for pumping out the molten metal flowing from the holding chamber,
A holding furnace comprising the impurity removal unit according to any one of claims 1 to 4, which is installed on a bottom wall of the pumping chamber or on a bottom wall of the holding chamber.

In the holding furnace described in paragraph 5, the impurity removal unit is preferably removably installed on the bottom wall of the pumping chamber or the bottom wall of the holding chamber, but may be integrated with the bottom wall of the pumping chamber or the bottom wall of the holding chamber.

In order to solve the above problems, the present invention also focuses on the melting furnace described in item 6 below.

Item 6. A melting furnace equipped with a melting chamber for melting metal,
A melting furnace comprising the impurity removal unit according to any one of claims 1 to 4, which is installed on a bottom wall of the melting chamber.

In the melting furnace described in paragraph 6, the impurity removal unit is preferably removably installed on the bottom wall of the melting chamber, but may be integrated with the bottom wall of the melting chamber.

In order to solve the above problems, the present invention also focuses on the transfer gutter described in item 7 below.

Item 7. A transfer trough for transferring molten metal,
A transfer trough comprising an impurity removal unit according to any one of items 1 to 4, installed on a bottom wall of the transfer trough.

In the transfer trough described in paragraph 7, the impurity removal unit is preferably removably installed on the bottom wall of the transfer trough, but may also be integrated with the bottom wall of the transfer trough.

The impurity removal unit of the present invention can effectively remove impurities such as precipitates and floating objects mixed in the molten metal. Therefore, for example, in a holding furnace equipped with an impurity removal unit, it is possible to prevent impurities from being mixed into the molten metal in the pumping chamber, in a melting furnace equipped with an impurity removal unit, it is possible to prevent impurities from being mixed into the molten metal flowing out of the melting furnace, and in a transfer trough equipped with an impurity removal unit, it is possible to prevent impurities from being mixed into the molten metal being delivered from a melting furnace or the like to various supply destinations.

FIG. 1 shows a schematic configuration of a holding furnace. FIG. 2 shows a perspective view of the impurity removal unit. FIG. 3 shows a plan view of the impurity removal unit. FIG. 4 is a perspective view of a cross section taken along line AA of FIG. FIG. 5 is a perspective view of a cross section taken along line BB of FIG.

The impurity removal unit of the present invention is intended to remove impurities that are mixed in with the molten metal from the molten metal. The impurities include sediments that sink to the bottom of the molten metal, as well as floating matter that floats on the surface of the molten metal. In other words, the impurity removal unit of the present invention can effectively remove from the molten metal sediments that sink to the bottom of the molten metal and floating matter that floats on the surface of the molten metal.

The impurity removal unit of the present invention can be applied to, for example, a melting furnace for melting metals such as aluminum and aluminum alloys, a holding furnace (including a melting and holding furnace) for holding molten metal at high temperatures, and a transfer trough for distributing molten metal from a melting furnace to various destinations. In a melting furnace, it is possible to prevent impurities from being mixed into the molten metal that flows out of the melting furnace through the outlet. In a holding furnace, it is possible to prevent impurities from being mixed into the molten metal that flows from the holding chamber into the pumping chamber and is pumped out. In a transfer trough, it is possible to prevent impurities from being mixed into the molten metal that is distributed to various destinations from a melting furnace. The impurity removal unit of the present invention can be applied to various machines, instruments, tools, and the like in which molten metal is present in a recess surrounded by side walls on the bottom wall and the molten metal can move in one direction above the bottom wall.

Below, an embodiment of the present invention will be described with reference to the attached drawings. In the following embodiment, an example of applying the impurity removal unit of the present invention to a holding furnace will be shown.

FIG. 1 shows a schematic configuration of a holding furnace 1 equipped with an impurity removal unit 10 according to this embodiment. The holding furnace 1 comprises at least a holding chamber 2 for holding molten metal, such as aluminum or an aluminum alloy, at high temperature, and a pumping chamber 3 for pumping out the molten metal. The molten metal is supplied, for example, from a melting furnace via a transfer trough. Alternatively, if the holding furnace 1 is a melting and holding furnace further equipped with a melting chamber for melting metal, the molten metal is supplied to the holding chamber 2 from the melting chamber.

The holding chamber 2 is in the shape of a container with an opening at the top, and is equipped with a bottom wall 20 and a side wall 21. The holding chamber 2 holds the molten metal in a space surrounded by the side wall 21 above the bottom wall 20. A lid 22 is removably provided at the top of the holding chamber 2. The top opening of the holding chamber 2 is closed by the lid 22 so that it can be opened and closed freely. A heater 4 such as a burner or heater is attached to the lid 22. The molten metal in the holding chamber 2 is heated by the heater 4 and held at a temperature higher than the melting temperature of the metal.

The pumping chamber 3 is disposed adjacent to the holding chamber 2. The pumping chamber 3 is in the shape of a container with an opening at the top, and includes a bottom wall 30 and a side wall 31. In this embodiment, the bottom wall 20 of the holding chamber 2 and the bottom wall 30 of the pumping chamber 3 are integral, and the side wall 21 of the holding chamber 2 and the side wall 31 of the pumping chamber 3 are integral. The holding chamber 2 and the pumping chamber 3 are separated by being partitioned by a partition wall 5. A molten metal communication section 50 is formed below the partition wall 5 and above the bottom walls 20 and 30, and the molten metal in the holding chamber 2 can move from the holding chamber 2 to the pumping chamber 3 (in the direction of the arrow X in FIG. 1) through the communication section 50 below the partition wall 5 on the bottom wall 20. When the molten metal is stored in the pumping chamber 3, the molten metal in the holding chamber 2 moves to the pumping chamber 3 when the molten metal in the pumping chamber 3 is pumped out and the liquid level of the molten metal drops.

The holding chamber 2 and pumping chamber 3 (and also the melting chamber) are formed, for example, by lining a casing made of a metal such as steel with a fireproof material. If necessary, a heat insulating material may be interposed between the casing and the fireproof material.

As shown in FIG. 1, the holding furnace 1 is equipped with an impurity removal unit 10 for the purpose of preventing impurities from being mixed into the molten metal that flows from the holding chamber 2 into the pumping chamber 3 and is pumped out from the pumping chamber 3. The impurity removal unit 10 can be installed on the bottom wall 20 of the holding chamber 2. As a result, when the molten metal moves in one direction (towards the pumping chamber 3) above the second wall 20 within the holding chamber 2 before flowing from the holding chamber 2 through the communication part 50 below the partition wall 5 into the pumping chamber 3, impurities mixed in the molten metal are removed from the molten metal by the impurity removal unit 10.

When the impurity removal unit 10 is installed on the bottom wall 20 of the holding chamber 2, it is preferable that the impurity removal unit 10 is arranged in close proximity to the partition wall 5. Since the communication part 50 below the partition wall 5 is the outlet for the molten metal in the holding chamber 2, when the impurity removal unit 10 is arranged in close proximity to the partition wall 5, impurities can be most effectively removed from the molten metal flowing from the holding chamber 2 to the pumping chamber 3. Note that the impurity removal unit 10 only needs to be close to the partition wall 5, and may be arranged immediately adjacent to the partition wall 5.

Alternatively, the impurity removal unit 10 can be installed on the bottom wall 30 of the pumping chamber 3. In this way, after the molten metal flows from the holding chamber 2 through the communication part 50 below the partition wall 5 into the pumping chamber 3, when the molten metal moves in one direction (the direction opposite to the holding chamber 2) above the bottom wall 30 within the pumping chamber 3, the impurities mixed in the molten metal are removed from the molten metal by the impurity removal unit 10.

The impurity removal unit 10 may be removably installed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3, or may be integrated with the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3. In this embodiment, the impurity removal unit 10 is removable from the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3. If the impurity removal unit 10 is removable, the holding chamber 2 and the pumping chamber 3 can be easily cleaned, for example, when cleaning the holding furnace 1, and the impurity removal unit 10 can also be easily cleaned and reused, which is preferable.

As shown in Figures 1 to 5, the impurity removal unit 10 includes at least two barriers 11 spaced apart along the direction of movement of the molten metal. In this embodiment, the impurity removal unit 10 includes two barriers 11. Here, the direction of movement of the molten metal is the direction in which the holding chamber 2 and the pumping chamber 3 are aligned (the direction of arrow X in Figure 1), since the molten metal moves from the holding chamber 2 to the pumping chamber 3 in the holding furnace 1.

The barrier 11 is a plate having a thickness, and can be formed from a fireproof material such as brick or cement. In this embodiment, the barrier 11 is rectangular. The height of the barrier 11 is designed so that when the barrier 11 is installed on the bottom wall 20 of the holding chamber 2 or on the bottom wall 30 of the pumping chamber 3, it is higher than the maximum liquid level of the molten metal, that is, the upper end of the barrier 11 always protrudes above the liquid level of the molten metal. The length of the barrier 11 is designed so that when the barrier 11 is installed on the bottom wall 20 of the holding chamber 2 or on the bottom wall 30 of the pumping chamber 3, no gaps are created between both ends of the barrier 11 in the length direction and the side wall 21 of the holding chamber 2 or the side wall 31 of the pumping chamber 3. By designing the height and length of the barrier 11 as described above, the barrier 11 is installed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3 so as to basically block the movement of the molten metal, that is, to block the movement of the molten metal in parts other than the first flow hole 12 and the second flow hole 13 described below. The thickness of the barrier 11 is designed to have a strength such that the barrier 11 is not easily damaged or deformed by the movement of the molten metal when the barrier 11 is installed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3.

A first flow hole 12 is formed in the lower part of the barrier 11A located at the most upstream side in the moving direction of the molten metal among the at least two barriers 11. The lower part of the barrier 11A is the part below 1/2 the height of the barrier 11A. The first flow hole 12 is located at a position significantly lower than the liquid level (hereinafter referred to as the "minimum liquid level of the molten metal") when the molten metal accumulated in the holding chamber 2 and the pumping chamber 3 of the holding furnace 1 in which the impurity removal unit 10 is installed, and in other places such as the melting chamber and the transfer trough of the melting furnace, is assumed to be reduced to the lowest level. The first flow hole 12 penetrates the barrier 11A in the thickness direction and allows the molten metal to move from one side of the barrier 11A to the other side. The shape and size of the first flow hole 12 are not particularly limited and can be designed to be an appropriate shape and size that allows the molten metal to move smoothly. For example, the shape of the first flow hole 12 can be a horizontally long rectangular shape in a cross-sectional view, and the size of the first flow hole 12 can be 50 mm long and 100 mm wide.

By forming the first flow hole 12 at the bottom of the barrier 11A, even if the molten metal passes through the barrier 11A through the first flow hole 12, the floating matter F floating on the surface of the molten metal hits the barrier 11A and cannot pass through it, and the floating matter F is prevented from moving together with the molten metal. This makes it possible to prevent as much as possible the floating matter F, which is one of the impurities mixed in the molten metal, from moving from the holding chamber 2 to the pumping chamber 3 and being present in the molten metal in the pumping chamber 3. This makes it possible to prevent the floating matter F from being mixed into the molten metal pumped out of the pumping chamber 3.

The position of the upper end of the first through hole 12 is preferably 50 mm to 200 mm below the lowest liquid level of the molten metal. This effectively prevents floating matter F from passing through the barrier 11A from the first through hole 12, even if the floating matter F on the liquid surface of the molten metal moves slightly downward along the barrier 11A as the molten metal moves. In addition, the position of the lower end of the first through hole 12 is preferably 50 mm to 100 mm above the position of, for example, the upper surface of the bottom wall 20, 30 of the holding furnace 1 on which the impurity removal unit 10 is installed, or the upper surface of the melting chamber or transfer trough of the melting furnace (hereinafter referred to as the "bottom wall on which the impurity removal unit 10 is installed"). This also reduces the passage of precipitate P that settles at the bottom of the molten metal through the barrier 11A from the first through hole 12 as the molten metal moves.

A second through hole 13 is formed in the upper part of at least one of the at least two barriers 11, the other barrier 11B. The upper part of the barrier 11B is the part above 1/2 the height of the barrier 11B. The second through hole 13 is located above the first through hole 12, and is located at a position significantly above the upper surface of the bottom wall on which the impurity removal unit 10 is installed, or the upper surface of the base 14 if the impurity removal unit 10 includes a base 14. The second through hole 13 penetrates the barrier 11B in the thickness direction, and allows the molten metal to move from one side of the barrier 11B to the other side. The shape and size of the second through hole 13 are not particularly limited, and can be designed to be an appropriate shape and size that allows the molten metal to move smoothly. For example, the shape of the second through hole 13 can be a horizontally long rectangle in cross section, and the size of the second through hole 13 can be 50 mm long and 100 mm wide.

By forming the second flow hole 13 at the top of the barrier 11B, even if the molten metal passes through the barrier 11A via the second flow hole 13, the precipitate P that settles at the bottom of the molten metal (near the bottom walls 20, 30) hits the barrier 11B and cannot pass through it, preventing the precipitate P from moving along with the molten metal. This makes it possible to minimize the movement of precipitate P, one of the impurities mixed in the molten metal, from the holding chamber 2 to the pumping chamber 3 and being present in the molten metal in the pumping chamber 3. This makes it possible to prevent the precipitate P from being mixed into the molten metal pumped out of the pumping chamber 3.

The position of the lower end of the second through hole 13 is preferably 200 mm to 600 mm above the position of the upper surface of the bottom wall or the upper surface of the base 14 on which the impurity removal unit 10 is installed. This effectively prevents the precipitate P that settles at the bottom of the molten metal from passing through the barrier 11B from the second through hole 13, even if it moves slightly upward along the barrier 11B as the molten metal moves. Note that when the barrier 11B on which the second through hole 13 is formed is disposed in close contact with the partition wall 5, the second through hole 13 is formed below the lower end of the partition wall 5. In addition, the position of the upper end of the second through hole 13 is preferably 50 mm to 100 mm below the position of the lowest liquid level of the molten metal. This prevents the floating matter F floating on the liquid level of the molten metal from passing through the barrier 11B from the second through hole 13 as the molten metal moves, even if the floating matter F is mixed in the molten metal that has passed through the barrier 11A.

The impurity removal unit 10 preferably includes at least two barriers 11, as well as a base 14 from which the barriers 11 stand. The base 14 is a plate with a certain thickness, and can be made of a fireproof material such as brick or cement. The base 14 is integrated with the at least two barriers 11. The base 14 is placed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3. This allows the at least two barriers 11 to be easily installed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3.

In this embodiment, the base 14 is rectangular. The thickness of the base 14 is designed to have a strength that does not easily damage or deform the base 14. The length of the base 14 is designed so that when the base 14 is installed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3, no gaps are created between both ends of the base 14 in the longitudinal direction and the side wall 21 of the holding chamber 2 or the side wall 31 of the pumping chamber 3. The width of the base 14 is designed so that all of the barriers 11 can be integrated on its upper surface.

The impurity removal unit 10 preferably includes at least two barriers 11, as well as a pair of guides 15 that sandwich the at least two barriers 11 from both sides. The guides 15 are plate-like with some thickness, and can be made of a fire-resistant material such as brick or cement. The pair of guides 15 are integrated with the at least two barriers 11. In this embodiment, the pair of guides 15 rise from the base 14 and are integrated with the base 14.

When the at least two barriers 11 are installed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3, the pair of guides 15 come into contact with the side wall 21 of the holding chamber 2 or the side wall 31 of the pumping chamber 3. As a result, when the at least two barriers 11 are inserted into the holding chamber 2 or the pumping chamber 3 and installed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3, the pair of guides 15 slide on the side wall 21 of the holding chamber 2 or the side wall 31 of the pumping chamber 3, so that the at least two barriers 11 can be easily inserted into the holding chamber 2 or the pumping chamber 3. In addition, when the at least two barriers 11 are installed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3, the pair of guides 15 come into contact with the side wall 21 of the holding chamber 2 or the side wall 31 of the pumping chamber 3, so that no gaps are generated between both ends of the barriers 11 in the length direction and the side wall 21 of the holding chamber 2 or the side wall 31 of the pumping chamber 3.

In this embodiment, the guide 15 has a rectangular shape in a plan view. The thickness of the guide 15 is designed to be strong enough to prevent the guide 15 from easily breaking or deforming. The width of the base 15 is designed to allow all the barriers 11 to be integrated together. The height of the guide 15 is designed to be greater than the maximum liquid level of the molten metal when the barriers 11 are installed on the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3, in other words, so that the upper end of the guide 15 always protrudes above the liquid level of the molten metal. In this embodiment, the height of the guide 15 and the height of the barriers 11 are the same.

The impurity removal unit 10 of this embodiment includes two barriers 11, a base 14, and a pair of guides 15, and has a box shape with an open top, with the two barriers 11 forming opposing front and rear surfaces, the base 14 forming the bottom surface, and the pair of guides 15 forming opposing side surfaces. This allows the impurity removal unit 10 to be easily installed on the bottom wall 20 of the holding chamber 2 or on the bottom wall 30 of the pumping chamber 3 by submerging the impurity removal unit 10 in the molten metal.

The impurity removal unit 10 is preferably formed with an embedded portion 16 for embedding a heater in at least one of the pair of guides 15 and/or the base 14. The embedded portion 16 is a cavity formed in the guide 15 or the base 14, and by embedding a heater, the molten metal can be indirectly heated. This makes it possible to suppress a drop in the temperature of the molten metal, so that the molten metal can be pumped out of the pumping chamber 3 while maintaining a high temperature. There are no particular limitations on the heater, so long as it can be embedded in the embedded portion 16.

The embedded portion 16 is preferably formed in at least one of the pair of guides 15, and the upper end of the embedded portion 16 is preferably open on the upper surface of the guide 15. This allows the heater to be easily embedded in the guide 15. Also, the embedded portion 16 is preferably L-shaped and extends from the guide 15 to the base 14. This allows the heater to be easily embedded in the base 14.

The impurity removal unit 10 preferably includes a degassing processor 17. The degassing processor 17 includes a gas introduction pipe 18 through which an inert gas is introduced, and a bubble generator 19 that generates bubbles of the inert gas.

The gas introduction pipe 18 is formed in a pipe shape with openings at both ends, and extends vertically along one of the pair of guides 15. One end of the gas introduction pipe 18 is connected to the bubble generator 19, and the other end of the gas introduction pipe 18 protrudes above the guide 15 and is connected to a gas supply pipe extending from an inert gas supply source. This concept includes insoluble gases, gases that do not dissolve in molten metal, and gases that are difficult to dissolve in molten metal. Insoluble gases can be, for example, inert gases such as argon, or gases such as nitrogen and chlorine. The gas introduction pipe 18 is made of a metal pipe body such as steel, stainless steel, or cast iron, covered with a porous fireproof material.

The bubble generator 19 is hollow and box-shaped, and in this embodiment, for example, is rectangular in plan view. The bubble generator 19 is attached to the base 14 so as to release bubbles above the base 14. The bubble generator 19 has an internal space and is made of the same metal body as the gas introduction pipe 18, and is covered with a porous fireproof material. One end of the bubble generator 19 is connected to one end of the gas introduction pipe 18, and an insoluble gas is introduced into the bubble generator 19.

The other end of the bubble generator 19 is provided with a release section 190 that converts the insoluble gas introduced into the bubble generator 19 into bubbles and releases them above the base 14. The release section 190 is composed of, for example, a number of gas circulation holes formed on the upper surface of the metallic main body that constitutes the bubble generator 19, and a large number of pores in the porous fireproof material. The insoluble gas introduced into the bubble generator 19 passes through the gas circulation holes and the pores in the porous fireproof material, where it is broken down into fine bubbles that are released above the base 14. Gases such as hydrogen dissolved in the molten metal are captured by the fine bubbles of insoluble gas rising in the molten metal, and are released from the molten metal to the outside.

The bubble generator 19 is embedded in the base 14, but may be placed on the base 14. The gas introduction pipe 18 is placed inside the guide 15, but may be partially or entirely embedded in the guide 15.

The degassing processor 17 is not limited to the configuration of the present embodiment described above, and any known degassing processor can be used.

The impurity removal unit 10 of the present embodiment described above includes at least two barriers 11 that are spaced apart along the direction of movement of the molten metal and block the movement of the molten metal. Of the at least two barriers 11, the barrier 11A located most upstream in the direction of movement of the molten metal has a first through hole 12 formed in the lower part through which the molten metal passes, and at least one other barrier 11B has a second through hole 13 formed in the upper part through which the molten metal passes. As a result, according to the impurity removal unit 10 of the present embodiment, even if the molten metal contains precipitates P and floating matter F as impurities, when the molten metal passes through the first through hole 12 in the lower part of the barrier 11A, the floating matter F is prevented from moving together with the molten metal by the barrier 11A, and when the molten metal passes through the second through hole 13 in the upper part of the barrier 11B, the precipitates P are prevented from moving together with the molten metal by the barrier 11B, so that the impurities are effectively removed from the molten metal by the movement of the molten metal.

Therefore, by applying the impurity removal unit 10 to the holding furnace 1, it is possible to prevent precipitates P from being mixed into the molten metal that flows from the holding chamber 2 into the pumping chamber 3 and is pumped out from the pumping chamber 3, so that clean (high-quality) molten metal with no or very few impurities can be used for casting, etc.

In addition, the impurity removal unit 10 of this embodiment has a box shape in which at least two barriers 22, a base 14, and a pair of guides 15 are integrated. Therefore, according to the impurity removal unit 10 of this embodiment, the impurity removal unit 10 can be easily installed in the holding furnace 1. Furthermore, the impurity removal unit 10 can be easily removed from the holding furnace 1, which makes it easy to clean the holding furnace 1 and the impurity removal unit 10, and allows the impurity removal unit 10 to be used again.

In addition, the impurity removal unit 10 of this embodiment has an embedded portion 17 for embedding a heater in at least one of the pair of guides 15 and/or the base 14. Therefore, the impurity removal unit 10 of this embodiment can suppress a decrease in the temperature of the molten metal.

The impurity removal unit 10 of this embodiment also includes a degassing processor 17 including a gas introduction pipe 18 into which an insoluble gas is introduced and a bubble generator 19 that generates bubbles of the insoluble gas, and the gas introduction pipe 18 extends along one of the pair of guides 15, and the bubble generator 19 is attached to the base 14 so as to release bubbles above the base 14. Thus, according to the impurity removal unit 10 of this embodiment, gases such as hydrogen dissolved in the molten metal can be removed from the molten metal by the bubbles.

Although one embodiment of the present invention has been described above, the above-mentioned embodiment is merely illustrative and not restrictive. Therefore, the present invention is not limited to the above-mentioned embodiment, and various modifications are possible without departing from the spirit of the present invention.

For example, in the above-described embodiment, the impurity removal unit 10 includes two barriers 11. In contrast, as a modified example, the impurity removal unit 10 may include three or more barriers 11. When the impurity removal unit 10 includes three or more barriers 11, the third and subsequent barriers have either the first through hole 12 or the second through hole 13 formed therein. For example, when the impurity removal unit 10 includes four barriers 11, the barrier 11A most upstream in the direction of movement of the molten metal has the first through hole 12 formed therein, the barrier 11B one downstream has the second through hole 13 formed therein, the barrier 11 one downstream has the first through hole 12 formed therein, and the barrier 11 one downstream has the second through hole 13 formed therein. In this way, by alternately forming the first through hole 12 and the second through hole 13 for the multiple barriers 11 arranged from the upstream side to the downstream side in the direction of movement of the molten metal, it is possible to effectively suppress the mixing of impurities such as floating matter F and precipitate P into the molten metal. It is not necessary to alternately form the first through holes 12 and the second through holes 13 in the multiple barriers 11. As long as the first through hole 12 is formed in the barrier 11A located most upstream in the direction of movement of the molten metal, and the second through hole 13 is formed in at least one other barrier 11B, the first through hole 12 or the second through hole 13 can be freely formed.

For example, in the above-described embodiment, the impurity removal unit 10 includes a pair of guides 15. In contrast, as a modified example, the impurity removal unit 10 may not include a pair of guides 15, and may have at least two barriers 11 integrated into the base 14.

For example, in the above-described embodiment, the impurity removal unit 10 includes a base 14. In contrast, as a modified example, the impurity removal unit 10 may not include a base 14, and may have at least two barriers 11 integrated with a pair of guides 15.

For example, in the above-described embodiment, the impurity removal unit 10 includes a base 14 and a pair of guides 15. In contrast, as a modified example, the impurity removal unit 10 may not include the base 14 and the pair of guides 15, and may be composed of only at least two barriers 11. In this case, the impurity removal unit 10 (at least two barriers 11) is integrated into the bottom wall 20 of the holding chamber 2 or the bottom wall 30 of the pumping chamber 3.

For example, in the embodiment described above, an embedded portion 16 for embedding a heater is formed in the guide 15 or base 14 of the impurity removal unit 10. In contrast, as a modified example, the molten metal may be heated directly by, for example, immersing an immersion heater or throw-in heater into the molten metal without forming an embedded portion 16 in the guide 15 or base 14 of the impurity removal unit 10. Alternatively, the molten metal may not need to be heated by a heater or the like in the impurity removal unit 10.

For example, in the embodiment described above, the impurity removal unit 10 is equipped with a degassing processor 17. In contrast, as a modified example, the impurity removal unit 10 does not need to be equipped with a degassing processor 17, and gases such as hydrogen contained in the molten metal do not need to be removed in the impurity removal unit 10.

For example, in the above-described embodiment, the impurity removal unit 10 is applied to the holding furnace 1. In contrast, as a modified example, the impurity removal unit 10 may be applied to a melting furnace. The melting furnace has at least a melting chamber for melting metal, and the molten metal produced by melting the metal in the melting chamber flows out from the tapping port. By installing the impurity removal unit 10 on the bottom wall of the melting chamber, the impurities of precipitates P and floating matter F mixed in the molten metal are removed by the impurity removal unit 10 while the molten metal moves to the tapping port. This makes it possible to prevent impurities from being mixed into the molten metal flowing out of the melting furnace. The impurity removal unit 10 is preferably installed in a position close to the tapping port on the bottom wall of the melting chamber.

The melting chamber may have a structure including a melting section for melting metal, and a tapping section that has a tapping outlet and receives molten metal from the melting section, holds the molten metal temporarily, and then lets it flow out of the tapping outlet. In this case, the impurity removal unit 10 is preferably installed on the bottom wall of the tapping section of the melting chamber, in a position close to the tapping outlet.

As another variation, the impurity removal unit 10 may be applied to a transfer gutter. The transfer gutter is formed in a concave shape in cross section, and transports molten metal flowing out from, for example, a melting furnace and distributes it to various supply destinations. By installing the impurity removal unit 10 on the bottom wall of the transfer gutter, the impurity removal unit 10 removes impurities such as precipitates P and floating matter F mixed in with the molten metal as the molten metal moves to various supply destinations. This makes it possible to prevent impurities from being mixed into the molten metal being distributed to various supply destinations from a melting furnace or the like.

REFERENCE SIGNS LIST 1 Holding furnace 2 Treatment tank 3 Electrolysis device 10 Impurity removal unit 11 Barrier 11A Barrier located most upstream in the direction of movement of molten metal among at least two barriers 11B At least one other barrier among at least two barriers 12 First flow hole 13 Second flow hole 14 Base 15 Guide 16 Embedded portion 17 Degassing device

Claims (7)

An impurity removal unit that is surrounded by a side wall and is installed on a bottom wall above which molten metal can move in one direction,
at least two barriers spaced apart along a direction of movement of the molten metal, the at least two barriers blocking the movement of the molten metal;
An impurity removal unit, wherein a first passage hole through which the molten metal passes is formed in the lower part of the barrier located most upstream in the direction of movement of the molten metal among the at least two barriers, and a second passage hole through which the molten metal passes is formed in the upper part of at least one of the other barriers. 2. The impurity unit according to claim 1,
a base resting on the bottom wall, the at least two barrier walls standing on the base;
a pair of guides extending from the base and sandwiching the at least two barriers from both sides;
an impurity unit, wherein the base, the at least two barriers and the pair of guides are integrated together; The impurity unit according to claim 2, wherein at least one of the pair of guides and/or the base has an embedded portion for embedding a heater. A degassing device is provided, the degassing device including a gas introduction pipe through which an insoluble gas is introduced and a bubble generator for generating bubbles of the insoluble gas,
3. The impurity unit of claim 2, wherein the gas inlet pipe extends along one of the pair of guides, and the bubble generator is attached to the base so as to emit bubbles above the base. A holding furnace including at least a holding chamber for holding molten metal and a pumping chamber for pumping out the molten metal flowing from the holding chamber,
A holding furnace comprising the impurity removal unit according to claim 1 , which is installed on a bottom wall of the pumping chamber or on a bottom wall of the holding chamber. A melting furnace having a melting chamber for melting metal,
A melting furnace comprising the impurity removal unit according to claim 1 , which is installed on a bottom wall of the melting chamber. A transfer trough for transferring molten metal,
A transfer trough comprising an impurity removal unit according to claim 1 , installed on a bottom wall of the transfer trough.

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