JP7312499B1 - metal melting furnace - Google Patents

Abstract

An object of the present invention is to speed up the melting time when melting a metal material in a molten metal. A molten metal furnace 1 for solving the above-mentioned problems accommodates a molten metal MM, and at least one of melting a metal material in the liquid of the flowing molten metal MM and raising the temperature of the molten metal MM. inside the metal melting chamber 13, an elongated molten metal heating body 2 for heating the molten metal MM is provided, and the molten metal heating body 2 is a side wall portion 13Ds of the metal melting chamber 13 The bottom surface 13Db1 of the metal melting chamber 13 located below the molten metal heater 2 DS is spaced apart from the molten metal heater 2 by a predetermined distance. It is inclined in the same direction as the heating element 2 . [Selection drawing] Fig. 2

Description

The present invention relates to a metal melting furnace for melting metals such as non-ferrous metals such as aluminum and aluminum alloys, and for raising the temperature of molten metals (hereinafter referred to as "molten metals").

Conventional methods of melting metals such as non-ferrous metals such as aluminum and aluminum alloys and raising the temperature of molten metal generally involve charging ingots, return materials, scraps (e.g. briquette material, cutting chips, etc.) into a melting furnace, melting them in the liquid of the molten metal using a heater or a burner, and raising the temperature of the molten metal.

For example, Patent Literature 1 discloses a melting furnace that melts a metal material into a molten material by heat of combustion gas (flame) from a burner and raises the temperature of the molten material.

Japanese Patent No. 6629477

However, in the conventional method, it cannot be said that the heat of the heater or burner is sufficiently transmitted to the metal materials such as ingots, return materials, scraps, etc., and it takes time to melt the metal materials and raise the temperature of the molten metal.

Accordingly, an object of the present invention is to shorten the dissolution time when dissolving a metal material in a molten metal without contact with air (hereinafter also referred to as "non-oxidation dissolution in liquid").

Modes of means for solving the above problems are as follows.

(First aspect)
A metal melting furnace comprising a metal melting chamber containing molten metal and performing at least one of melting a metal material in the flowing molten metal and raising the temperature of the molten metal,
An elongated molten metal heater for heating the molten metal is provided inside the metal melting chamber,
The molten metal heater is provided to extend downward from a side wall portion of the metal melting chamber,
A metal melting furnace, wherein a bottom surface of the metal melting chamber positioned below the molten metal heater is inclined in the same direction as the molten metal heater while maintaining a predetermined gap from the molten metal heater.

(Effect)
According to the molten metal furnace of the first aspect, the flow velocity of the molten metal in the gap between the molten metal heater and the bottom surface of the metal melting chamber at a predetermined interval is increased, so that the heat transfer efficiency from the molten metal heater to the molten metal can be increased. As a result, the melting time of the metal material in the molten metal can be shortened.

In addition, in a conventional metal melting chamber having a substantially cubic shape or a substantially rectangular parallelepiped shape in which a molten metal heating member is placed vertically, the height of the metal melting chamber has to be increased to some extent in order to accommodate the molten metal heating member in the metal melting chamber. However, when the height of the metal melting chamber increases, when the metal melting chamber and existing equipment (for example, a hot water supply equipment for a die casting machine, which has a maximum height of about 1200 mm; the same shall apply hereinafter) are installed side by side, the height of the metal melting chamber often becomes higher than the existing equipment. When there is a difference in height between the metal melting chamber and the existing equipment, there is a risk that the operating efficiency of the existing equipment will deteriorate.

In order to prevent such inconveniences from occurring, it is conceivable to reduce the height and widen the width of the metal melting chamber so that the metal melting chamber has the same capacity as the conventional metal melting chamber, and install a short length and large diameter molten metal heating element vertically in the metal melting chamber. However, since such a molten metal heater is a custom-made product, it is significantly more expensive (approximately 10 times the price) than conventional molten metal heaters, and there is an inconvenience that the initial cost increases.

On the other hand, in the conventional metal melting chamber in which the molten metal heating element is placed horizontally, the width of the metal melting chamber must be widened, which inevitably increases the area of the bottom surface of the metal melting chamber. As the melting of the metal progresses, unwanted matter accumulates on the bottom surface of the metal melting chamber. However, if the area of the bottom surface of the metal melting chamber is large, the unwanted matter is scattered all over the bottom surface of the metal melting chamber, which is inconvenient in that it takes time and effort to collect the unwanted matter.

In order to solve the above problems, in the first mode, the molten metal heater is obliquely arranged, that is, the molten metal heater is provided so as to extend downward from the side wall of the metal melting chamber. By adopting such a structure, the height of the metal melting chamber can be made lower than that of a conventional metal melting chamber in which the molten metal heating element is vertically placed. As a result, it is possible to prevent the inconvenience of lowering the operating efficiency of the existing equipment. In addition, since the area of the bottom surface of the metal melting chamber can be made smaller than that of the conventional metal melting chamber in which the molten metal heating body is placed horizontally, the trouble of collecting unnecessary materials accumulated on the bottom surface of the metal melting chamber can be reduced.

In addition, in the first embodiment, the bottom surface of the metal melting chamber is inclined in the same direction as the molten metal heater while keeping a predetermined gap from the molten metal heater. By inclining the bottom surface of the metal melting chamber in this way, the above-mentioned unnecessary materials gather at the lowest portion of the bottom surface of the metal melting chamber, so that the labor for collecting the unnecessary materials accumulated on the bottom surface of the metal melting chamber can be further reduced.

Furthermore, by inclining the bottom surface of the metal melting chamber, it is possible to reduce the volume of the metal melting chamber and the amount of molten metal contained in the metal melting chamber as compared with conventional metal melting chambers having a substantially cubic shape or a substantially rectangular parallelepiped shape. Therefore, if the output of the molten metal heater is the same as the conventional one, the heat of the molten metal heater corresponding to the reduction of the molten metal can be used to raise the temperature of the molten metal, and as a result, the heating time of the molten metal can be shortened.

(Second aspect)
The bottom surface of the metal melting chamber is
an inclined surface positioned below the molten metal heating body and inclined substantially parallel to the molten metal heating body;
a laterally extending surface extending laterally from the lower end of the inclined surface;
The molten metal furnace according to the first aspect, wherein above the laterally extending surface is a waste collection portion in which wastes contained in the molten metal are accumulated.

(Effect)
Conventional metal melting furnaces also had the following problems. That is, when ingots, return materials, scraps, and the like are put into the molten metal furnace, the outside air comes into contact with the molten metal in the molten metal furnace. Also, the air filling the space between the upper lid of the metal melting chamber and the molten metal comes into contact with the molten metal. As described above, when air and molten metal come into contact with each other, oxides are generated in the molten metal. Furthermore, ingots and the like contain heavy metals such as copper, iron and zinc, so that by-products are generated when the ingots and the like are melted. Since these oxides and by-products are scattered and accumulated on the bottom surface of the metal melting chamber with the passage of time, there is a problem that it takes time and effort to recover them using a ladle or the like.

Unnecessary substances (referring to the aforementioned oxides and by-products, hereinafter referred to as "unnecessary substances") contained in the molten metal gradually drop to the bottom of the metal melting chamber due to gravity over time. At this time, by inclining a portion of the bottom surface of the metal melting chamber as in the second aspect, the unwanted matter can be retained on the laterally extending surface extending laterally from the lower end of the inclined surface. That is, the waste naturally accumulates on the laterally extending surfaces rather than being scattered across the bottom surface of the metal melting chamber. Therefore, when collecting unnecessary substances using a ladle or the like, the unnecessary substances accumulated on the laterally extending surface can be scooped out, so that the collection efficiency of unnecessary substances can be improved.

(Third aspect)
A lid is provided on the upper part of the metal melting chamber to cover the metal melting chamber,
The metal melting furnace according to the first aspect, wherein the lid of the metal melting chamber positioned above the molten metal heater is inclined in the same direction as the molten metal heater while maintaining a predetermined gap from the previous molten metal heater.

(Effect)
According to the molten metal furnace of the third aspect, the molten metal flows faster in the gap between the molten metal heater and the lid of the metal melting chamber, so that the efficiency of heat transfer from the molten metal heater to the molten metal can be increased. As a result, the melting time of the metal material in the molten metal can be made faster.

In addition, since the lid of the metal melting chamber is inclined in the same direction as the molten metal heating body, the volume of the metal melting chamber is reduced compared to the conventional metal melting chamber having a substantially cubic shape or a substantially rectangular parallelepiped shape, thereby reducing the amount of molten metal to be accommodated. Therefore, if the output of the molten metal heater is the same as the conventional one, the heat of the molten metal heater corresponding to the reduction of the molten metal can be used to raise the temperature of the molten metal, and as a result, the heating time of the molten metal can be shortened.

(Fourth aspect)
A metal melting furnace comprising a metal melting chamber containing molten metal and performing at least one of melting a metal material in the flowing molten metal and raising the temperature of the molten metal,
An elongated molten metal heater for heating the molten metal is provided inside the metal melting chamber,
The molten metal heater is provided to extend downward from a side wall portion of the metal melting chamber,
A lid is provided on the upper part of the metal melting chamber to cover the metal melting chamber,
A metal melting furnace, wherein a lid of the metal melting chamber positioned above the molten metal heater is inclined in the same direction as the molten metal heater while maintaining a predetermined gap from the previous molten metal heater.

(Effect)
According to the fourth aspect of the molten metal furnace, the flow rate of the molten metal in the gap between the molten metal heating element and the lid of the metal melting chamber is increased, so that the heat transfer efficiency from the molten metal heating element to the molten metal can be increased. As a result, the melting time of the metal material in the molten metal can be shortened.

In addition, since the lid of the metal melting chamber is inclined in the same direction as the molten metal heating body, the volume of the metal melting chamber is reduced compared with the conventional metal melting chamber having a substantially cubic shape or a substantially rectangular parallelepiped shape, thereby reducing the amount of molten metal to be accommodated. Therefore, if the output of the molten metal heater is the same as the conventional one, the heat of the molten metal heater corresponding to the reduction of the molten metal can be used to raise the temperature of the molten metal, and as a result, the heating time of the molten metal can be shortened.

According to the present invention, the melting time can be shortened when the metal material is melted in the molten metal.

1 is a schematic plan view showing a molten metal furnace according to a first embodiment; FIG. 2 is a cross-sectional view of the metal melting chamber of FIG. 1 taken along line Z1-Z1; FIG. FIG. 4 is a schematic cross-sectional view showing an example of a flow generator and a flow generation chamber; Fig. 2 is a schematic plan view showing a molten metal furnace according to a second embodiment; FIG. 5 is a cross-sectional view of the metal melting chamber of FIG. 4 taken along line Z2-Z2; FIG. 3 is a schematic plan view showing a metal melting furnace according to a third embodiment; FIG. 4 is a cross-sectional view showing a metal melting chamber according to a comparative example;

Embodiments of the present invention will be described below.

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a molten metal furnace 1 according to the present invention will be described below with reference to the drawings. It should be noted that the following description and drawings merely show an example of the embodiment of the present invention, and the content of the present invention should not be construed as being limited to this embodiment.

(First embodiment)
FIG. 1 shows a first embodiment of a molten metal furnace 1 according to the present invention. This molten metal furnace 1 includes an ingot charging chamber 11 for charging an ingot, a return material charging chamber 12 for charging a return material, a metal melting chamber 13 for at least one of melting a metal material in the fluid of the flowing molten metal MM and raising the temperature of the molten metal MM, a flow generating chamber 14 having a flow generating device 4 for flowing the molten metal MM, a residue removing chamber 15 for removing residue in the molten metal MM, and metal. It has a tapping chamber 16 for tapping the molten metal MM in which the material is melted.

As for the melting of the metal material performed in the metal melting chamber 13, the ingot that has not been completely melted in the ingot charging chamber 11 or the return material charging chamber 12 by the flowing molten metal MM and the return material that has not been completely melted in the return material charging chamber 12 by the flowing molten metal MM are melted in the metal melting chamber 13.

(Flow of molten metal MM)
The ingot charging chamber 11, the return material charging chamber 12, the metal melting chamber 13, the flow generating chamber 14 and the residue removing chamber 15 are arranged in this order in a ring. The flow of molten metal MM will be described in detail below.

First, an ingot is charged into the molten metal MM in the ingot charging chamber 11, and the molten metal MM including the ingot melted in the ingot charging chamber 11 and the ingot not completely melted in the ingot charging chamber 11 by the flowing molten metal MM flows through the first transport path W1 to the return material charging chamber 12. Then, a new return material is introduced into the molten metal MM in the return material introduction chamber 12 . This return material has various shapes because it is an unnecessary part generated in the casting process. Before charging the return material into the return material charging chamber 12, the return material is crushed in advance by a breaker device, and the crushed return material is transferred by a conveyor and charged into the return material charging chamber 12.例文帳に追加The molten metal MM including the return material melted in the return material charging chamber 12 by the flowing molten metal MM and the return material not completely melted in the return material charging chamber 12 flows to the metal melting chamber 13 through the second conveying path W2.

In the metal melting chamber 13, the molten metal MM is heated by the molten metal heating element 2 (for example, a heater), and at least one of (1) melting at least one of the ingot and the return material that has not been completely melted in the molten metal MM and (2) raising the temperature of the molten metal MM is performed.

A part of the molten metal MM in the metal melting chamber 13 flows to the flow generating chamber 14 through the third conveying path W3. In the flow generating chamber 14, the flow generating device 4 generates a circulation flow of the molten metal MM that flows in the order of the ingot charging chamber 11, the return material charging chamber 12, the metal melting chamber 13, the flow generating chamber 14, the residue removing chamber 15, the ingot charging chamber 11, and so on. The molten metal MM in the flow generation chamber 14 flows to the residue removal chamber 15 through the fourth conveying path W4.

As described above, it is preferable to circulate the molten metal MM among the ingot charging chamber 11, the return material charging chamber 12, the metal melting chamber 13, the flow generating chamber 14, and the residue removing chamber 15. The purpose of circulating the molten metal MM is as follows.

That is, the ingot and the return material (hereinafter referred to as the "object") are thrown into the molten metal MM in a solid state, and the object itself becomes a non-oxidized state in the molten metal MM without being exposed to air. Since the molten metal MM surrounds the entire object, the heat of the molten metal MM is evenly transmitted to the object, and the object begins to melt. At that time, the temperature of the molten metal MM in the portion (periphery) surrounding the entire object decreases, and the temperature distribution of the molten metal MM becomes non-uniform. The molten metal MM is circulated for the purpose of eliminating this uneven temperature distribution and maintaining a uniform temperature.

Here, the configuration of the flow generator 4 will be described in detail. FIG. 3 shows an outline of an example of the flow generator 4. As shown in FIG. The flow generating device 4 includes a motor 4A provided outside the flow generating chamber 14, a rotating shaft 4B extending from the upper portion US to the lower portion DS of the flow generating chamber 14 and rotated by the motor 4A, and a stirring blade 4C positioned below the flow generating chamber 14 and provided at the lower end of the rotating shaft 4B. The rotary shaft 4B has a driven shaft 4Ba positioned inside the flow generation chamber 14 and an output shaft 4Bb positioned outside and above the flow generation chamber 14. As shown in FIG. Another rotating shaft 4Aa is also provided above the motor 4A. Gears 4Ga and 4Gb are attached to the output shaft 4Bb and the rotary shaft 4Aa, respectively, and these gears 4Ga and 4Gb are connected by a belt 4V. With the above structure, the motor 4A rotates the stirring blade 4C. In FIG. 3, the stirring blade 4C rotates clockwise, but if the flow of the molten metal MM is to be reversed, the direction of rotation OT of the stirring blade 4C should be reversed (counterclockwise).

A supply port 14A for the molten metal MM that flows from the metal melting chamber 13 into the flow generation chamber 14 is provided on one side (left side in the drawing) of the lower side wall of the flow generation chamber 14, and an outlet 14B for the molten metal MM that flows out from the flow generation chamber 14 to the residue removal chamber 15 is provided on the other side (right side in the drawing) of the lower side wall of the flow generation chamber 14. A lid 14C is provided above the flow generation chamber 14 to prevent the molten metal MM in the flow generation chamber 14 from spilling out. Although the heat insulating material 20 is not shown in the example of FIG. 3, it is preferable to provide the heat insulating material 20 outside the container 14D of the flow generating chamber 14 in order to prevent the temperature of the molten metal MM from dropping.

Also, the configuration of the flow generator 4 and the flow generation chamber 14 in FIG. 3 is merely an example, and these configurations may be changed as appropriate. For example, the motor 4A may be directly attached to the output shaft 4Bb, the shape of the stirring blade 4C may be a screw type, a propeller type, or the like (the stirring blade 4C in FIG. 3 is a paddle type), or a nozzle without using the stirring blade 4C. It may be configured to inject gas such as nitrogen. In addition, the positions of the stirring blade 4C, the supply port 14A, and the discharge port 14B are preferably at the same height in order to efficiently flow the molten metal MM, but these heights may be arranged above the position US shown in FIG.

Furthermore, in the inner space of the container 14D of the flow generation chamber 14 in FIG. 3, the flow of the molten metal MM generated by the stirring blades 4C becomes a whirlpool, so it is preferable that the inner space of the container 14D of the flow generation chamber 14 has a substantially cylindrical shape so as not to impede the whirlpool.

The molten metal MM discharged from the flow generation chamber 14 as described above is removed in the residue removal chamber 15 by scooping up residues in the molten metal MM (oxidation protection film formed on the liquid surface of the molten metal MM, oxides floating in the molten metal MM, etc.) with a ladle. Alternatively, powdery metal-dissolving flux may be sprinkled in advance, and the residue may be absorbed by the flux and removed. The molten metal MM from which the residue has been removed flows into the ingot charging chamber 11 through the fifth transport path W5. The subsequent flow of the molten metal MM after returning to the ingot charging chamber 11 is the same as described above, so the description is omitted here.

Also, part of the molten metal MM in which the ingot and the return material are melted in the metal melting chamber 13 flows to the tapping chamber 16 through the sixth transport path W6. A portion of the molten metal MM in the tapping chamber 16 is tapped to a subsequent casting machine, die casting machine, or the like at an appropriate timing. In order to prevent the temperature of the molten metal MM in the tapping chamber 16 from dropping, it is preferable to provide a molten metal heating element 2 such as a heater inside the tapping chamber 16 as well.

As described above, the molten metal MM flows through the ingot charging chamber 11, the return material charging chamber 12, the metal melting chamber 13, the flow generating chamber 14, the residue removing chamber 15, and the tapping chamber 16. Since these chambers are connected to each other, the surface ML of the molten metal MM in each of the ingot charging chamber 11, return material charging chamber 12, metal melting chamber 13, flow generating chamber 14, residue removing chamber 15, and tapping chamber 16 remains constant even when an ingot or return material is charged or a part of the molten metal MM is discharged.

As for the direction MR of the circulating flow of the molten metal MM, in the above description, it was described that the molten metal MM flows counterclockwise in FIG. 1, but the molten metal MM may flow clockwise. That is, the molten metal MM may flow through the ingot charging chamber 11, the residue removing chamber 15, the flow generation chamber 14, the metal melting chamber 13, the return material charging chamber 12, the ingot charging chamber 11, . However, in order to prepare for the pouring of the molten metal MM, among the ingots charged into the ingot charging chamber 11, the ingots that have not been completely melted in the ingot charging chamber 11 and among the return materials that have been charged into the return material charging chamber 12, the return materials that have not been completely melted in the return material charging chamber 12 are preferably quickly dissolved in the molten metal MM without oxidation. From this point of view, it is preferable to flow the ingot and the return material to the metal melting chamber 13 as quickly as possible, so it is preferable to flow the molten metal MM counterclockwise as shown in FIG. The direction in which the molten metal MM flows can be changed by the flow generator 4. For example, the direction of rotation of the rotor blades 4C may be reversed.

(Metal melting chamber 13)
Next, the metal melting chamber 13 will be described in detail. The metal melting chamber 13 is a space inside the metal melting chamber container 13D, and the metal melting chamber 13 holds the molten metal MM. The molten metal MM contains the ingot that was not completely melted in the ingot charging chamber 11 and the return material that was not completely melted in the return material charging chamber 12 . Before pouring the molten metal MM from the pouring chamber 16, it is necessary to melt the ingot not completely melted in the ingot charging chamber 11 in the molten metal MM and the return material not completely melted in the return material charging chamber 12.例文帳に追加Therefore, in the metal melting chamber 13, a molten metal heater 2 is provided for heating the molten metal MM to melt the ingot not completely melted in the ingot charging chamber 11 in the molten metal MM and the return material not completely melted in the return material charging chamber 12.例文帳に追加

The molten metal heating body 2 is not particularly limited, but it is preferable that it does not hinder the flow of the molten metal MM in the molten metal chamber 13, and since it has less resistance when flowing than the plate-shaped heating body, an elongated heating body is preferable. Specifically, it is preferable to use a tube-shaped one such as a tube burner or a tube heater.

A base end portion of the molten metal heater 2 is provided on a side wall portion of the metal melting chamber 13 . In the example of FIG. 2, the base end portion of the molten metal heater 2 is attached to the upper portion of the side wall 13Ds (the left side wall in the drawing) of the metal melting chamber container 13D and the upper portion of the side wall (the left side wall in the drawing) of the heat insulating material 13E located outside the metal melting chamber container 13D, with the metal melting chamber container 13D and the heat insulating material 13E penetrating therethrough. The molten metal heater 2 extends downward from the side wall portion of the metal melting chamber 13 . In the example of FIG. 2, the molten metal heater 2 extends from the upper side wall 13Ds (the side wall on the left side of the drawing) of the metal melting chamber container 13D toward the opposite floor portion 13Db (the floor portion on the right side of the drawing). Alternatively, the molten metal heater 2 can be said to extend from the top of the side wall 13Ds (left side wall in the drawing) of the metal melting chamber container 13D toward the bottom of the opposite side wall 13Ds (right side wall in the drawing).

The inclination angle of the molten metal heater 2 can be arbitrarily determined, but the angle α of the depression angle between the axis 2x of the molten metal heater 2 and the virtual horizontal line 2y is preferably 20 to 45 degrees, and more preferably 30 to 40 degrees.

When the angle α is smaller than 20 degrees, the height of the metal melting chamber 13 can be suppressed. As a result, as described above, there is an advantage that it is possible to prevent the occurrence of the inconvenience that the operating efficiency of the existing equipment or the like is lowered.

However, if the height of the metal melting chamber 13 is too low, it becomes necessary to change the heights of the return material charging chamber 12 and the flow generation chamber 14 . If the heights of the return material charging chamber 12 and the flow generating chamber 14 are not changed, the heights of the respective chambers 12, 13, and 14 are greatly different, so that the shape of each transport path (second transport path W2 and third transport path W3) of the return material charging chamber 12 and the flow generating chamber 14, which are connected to the metal melting chamber 13, becomes distorted, making it difficult for the molten metal MM to flow.

Also, if the height of the metal melting chamber 13 is set too low relative to the heights of the return material charging chamber 12 and the flow generating chamber 14 (for example, if the height of the metal melting chamber 13 is significantly lower than the height of the return material charging chamber 12), too much molten metal MM may flow into the metal melting chamber 13 and overflow from the melting metal chamber 13.

From the above, it is not preferable to make the height of the metal melting chamber 13 too low, and it is necessary to set the height above a certain level. Thus, there is no need to make the angle α of the molten metal heating element 2 too small in the first place.

On the other hand, as the angle α of the molten metal heater 2 becomes smaller, the extending direction of the molten metal heater 2 becomes closer to horizontal, so the width of the metal melting chamber 13 needs to be increased to accommodate the molten metal heater 2. As a result, there arises the inconvenience that a large space is required for installing the metal melting chamber 13 . Further, when the width of the metal melting chamber increases, the area of the bottom surface of the metal melting chamber tends to increase. If the area of the bottom surface of the metal melting chamber is large, there is an inconvenience that unnecessary substances are scattered all over the bottom surface of the metal melting chamber, and it takes a lot of labor to collect the unnecessary substances.

From the above, it is preferable that the angle α of the molten metal heater 2 is 20 degrees or more.

On the other hand, if the angle α is larger than 45 degrees, the height of the metal melting chamber 13 that accommodates the molten metal heating element 2 cannot be suppressed, and as described above, there is a possibility that the operating efficiency of the existing equipment will be lowered.

Due to the operational inconvenience as described above, the angle α is preferably 45 degrees or less.

In the example of FIG. 2, the left and right side walls 13Ds of the metal melting chamber container 13D are substantially vertical, and the floor 13Db on the right side of the drawing is substantially horizontal. On the other hand, the floor portion 13Db on the left side of the drawing of the molten metal chamber container 13D is inclined downward from the left side to the right side of the drawing, similarly to the molten metal heater 2 . The inclination angle β of the inclined floor surface 13Db1 of the floor portion 13Db of the metal melting chamber container 13D (the depression angle β between the extension line 13Dx of the inclined floor surface 13Db1 and the imaginary horizontal line 13Dy) is preferably substantially the same as the inclination angle α of the molten metal heater 2. For example, when the inclination angle α of the molten metal heater 2 is 35 degrees, the inclination angle β of the inclined floor surface 13Db1 is preferably about 33 to 37 degrees, most preferably 35 degrees. By aligning the respective inclination angles α and β described above, the molten metal heater 2 and the inclined floor surface 13Db1 can be made substantially parallel. Therefore, the distance X between the surface of the molten metal heater 2 and the floor 13Db (inclined floor surface 13Db1) (the distance in the direction perpendicular to the axis 2x of the molten metal heater 2) is almost the same everywhere. As a result, since heat can be uniformly transferred from the molten metal heating body 2 to the molten metal MM flowing in the space Y between the molten metal heating body 2 and the inclined floor surface 13Db1, the ingot that has not been completely melted in the ingot charging chamber 11 and the return material that has not been completely melted in the return material charging chamber 12 can be prevented from remaining unmelted.

That is, the ingot that has not been completely melted in the ingot charging chamber 11 in the molten metal MM and the return material that has not been completely melted in the return material charging chamber 12 in the molten metal MM tend to melt more easily as the molten metal heating body 2 that is the heat generation source is approached. Therefore, the temperature is higher than other spaces (for example, the upper right space above the molten metal heating element 2 in FIG. 2), and the ingot that has not been completely melted in the ingot charging chamber 11 and the return material that has not been completely melted in the return material charging chamber 12 are easily melted (hereinafter referred to as "easy-melting space Y" in the sense of a space in which the ingot or the like that has not been completely melted can be easily melted.). By making the distance X between the surface of the molten metal heating body 2 and the inclined floor surface 13Db1 substantially the same at any position in the axial direction of the molten metal heating body 2, the temperature in the easy-melting space Y becomes substantially the same at any position. As a result, it is possible to prevent the ingot that has not been completely melted in the ingot charging chamber 11 and the return material that has not been completely melted in the return material charging chamber 12 from remaining unmelted.

In addition, in the metal melting chamber 13 shown in FIG. 2, the distance X between the molten metal heater 2 and the floor portion 13Db (or the left side wall 13Ds in FIG. 7; the same shall apply hereinafter) is shorter than in the case where the floor portion 13Db of the metal melting chamber 13 is not inclined as shown in FIG. As a result, in the metal melting chamber 13 shown in FIG. 2, the flow velocity of the molten metal MM flowing through the easy melting space Y becomes faster than in the metal melting chamber 13 shown in FIG. By flowing a large amount of the molten metal MM into the easy-melting space Y at a high speed, the amount of the molten metal MM in contact with the surface of the molten-metal heating body 2 on the easy-melting space Y side is increased, and the heat from the molten-metal heating body 2 is easily transmitted to the molten metal MM. Thus, the ingot not completely melted in the ingot charging chamber 11 and the return material not completely melted in the return material charging chamber 12 in the molten metal MM can be melted more quickly.

Furthermore, by inclining the floor portion 13Db of the metal melting chamber 13, the speed of the molten metal MM flowing in the easy-melting space Y can be increased, so that the amount of the molten metal MM in contact with the surface of the molten-metal heater 2 on the easy-melting space Y side can be increased. As a result, the heat from the molten metal heater 2 is easily transmitted to the molten metal MM, and by charging the metal material such as an ingot or a return material, it is possible to shorten the time for raising the temperature of the molten metal around the metal material, which has dropped temporarily, and to quickly raise the temperature of the molten metal MM. Further, according to the metal melting chamber 13 of the first embodiment and the like, the decreased temperature of the molten metal MM around the object can be raised in a short time, so that the heat of the molten metal MM can be promoted to the object.

When the inclined floor surface 13Db1 is provided in the metal melting chamber container 13D as shown in FIG. 2, the distance X from the surface of the molten metal heater 2 to the inclined floor surface 13Db1 is preferably 7 to 13 cm, more preferably 10 to 11 cm. If the distance X is shorter than 7 cm, the easy-melting space Y becomes too small, so the amount of the molten metal MM flowing in the easy-melting space Y per unit time is reduced. On the other hand, if the distance X is longer than 13 cm, the easy-melting space Y becomes too large, making it difficult to increase the temperature of the easy-melting space Y. As a result, the melting speed of the ingot that has not been completely melted in the ingot charging chamber 11 in the metal melting chamber 13 and the return material that has not been completely melted in the return material charging chamber 12 may be slowed down. In addition, since the speed of the molten metal MM flowing through the easy-melting space Y does not increase, the amount of the molten metal MM in contact with the surface of the molten-metal heating element 2 on the easy-melting space Y side is reduced, so that the heat from the molten-metal heating element 2 becomes difficult to transfer to the molten metal MM, and there is a possibility that the temperature of the molten metal MM cannot be increased.

In addition, in the comparative example shown in FIG. 7, precisely, the distance between the molten metal heating element 2 and the floor 13Db below it varies widely. The distance X in such a case refers to the average distance from the molten metal heater 2 to the floor 13Db below it.

As shown in FIG. 2, the floor portion 13Db of the metal melting chamber container 13D has a lateral extension surface 13Db2 extending laterally from the lower end portion of the inclined floor surface 13Db1. The side extending surface 13Db2 extends laterally substantially horizontally from the lower end of the inclined floor surface 13Db1.

When the air filling the space AR between the lid portion 13C of the metal melting chamber 13 and the surface ML of the molten metal MM comes into contact with the molten metal MM, oxides are generated in the molten metal MM. Furthermore, since the ingot and return material contain heavy metals such as copper, iron and zinc, by-products are generated when the ingot and return material are melted. These oxides and by-products (hereinafter referred to as “unnecessary substances” in the sense of unnecessary substances) are gradually accumulated on the floor 13Db of the metal melting chamber 13 by gravity over time.

As shown in FIG. 2, by providing an inclined floor surface 13Db1 on the floor portion 13Db of the metal melting chamber 13, unwanted substances falling on the inclined floor surface 13Db1 roll down along the inclination of the inclined floor surface 13Db1 and stay on the side extending surface 13Db2. In other words, the unwanted matter is not scattered over the entire bottom surface of the metal melting chamber 13, but naturally gathers on the laterally extending surface 13Db2. Therefore, when the opening 13Ca provided in the lid portion 13C is opened and a ladle or the like is inserted into the metal melting chamber 13 through the opening 13Ca to rake up and recover the unnecessary materials, the unnecessary materials accumulated on the side extending surface 13Db2 can be scooped up. Therefore, compared to the case where the inclined floor surface 13Db1 is not provided as shown in FIG. 7, the efficiency of collecting unnecessary materials can be improved.

Further, as shown in FIGS. 1 and 2, it is preferable to provide a recessed portion (groove portion 13Db3) in the side extending surface 13Db2. By providing such a groove portion 13Db3, when collecting unnecessary objects, the unnecessary objects on the side extending surface 13Db2 are dropped into the groove portion 13Db3, and then the ladle is placed inside the groove portion 13Db3.

In the first embodiment, the residue removal chamber 15 is installed, but the frequency of residue removal is low, for example, about once a month. Therefore, the residue removal chamber 15 does not necessarily need to be installed in practice, and the residue removal chamber 15 does not have to be installed as in the third embodiment shown in FIG. Even if the residue removing chamber 15 is not provided, the residue in the molten metal MM can be removed by scooping the residue with a ladle even in the facilities such as the ingot charging chamber 11, the return charging chamber 12, and the metal melting chamber 13. Further, instead of scooping the residue with a ladle, it is also possible to sprinkle powdery metal-dissolving flux on each of the above-mentioned facilities in advance, and remove the residue by allowing the flux to adsorb the residue.

(Second embodiment)
FIG. 4 shows the molten metal furnace 1 according to the second embodiment. In the following description, description of the same parts as in the first embodiment will be omitted, and only different parts will be described.

The second embodiment is characterized in that the residue removal chamber 15 is not provided after the flow generation chamber 14, and a scrap melting chamber 17 for melting scrap is provided instead of the residue removal chamber 15. FIG.

Briquettes, which are scraps, are obtained by compressing and solidifying shavings, chips, etc. generated during processing, and contain oil and water. That is, it is difficult to melt scrap into molten metal in the same manner as ingots and return materials, and it is desirable to perform pretreatment such as drying in advance to evaporate moisture and oil.

In addition, briquettes have a low specific gravity and a large surface area compared to molten metal, so they tend to float on the surface of the molten metal and are partially oxidized during melting. Similarly, chips have a low specific gravity and a large surface area, so they tend to float on the surface of the molten metal and are partially oxidized.

Therefore, a vortex is generated by the flow generating device 4 in the flow generating chamber 14, and this vortex is flowed into the scrap melting chamber 17 via the seventh conveying path W7. In the scrap melting chamber 17, the scrap is thrown into the eddy current that has flowed. The introduced scrap is drawn into the bottom of the vortex at the center of the vortex. As a result, the scrap does not float on the surface of the molten metal, so that it is difficult for the scrap to come into contact with the outside air and to form oxides.

It should be noted that the seventh conveying path W7 is preferably installed in the tangential direction of the vortex generated by the flow generator 4 . As a result, the vortex flow can flow into the scrap melting chamber 17 without deceleration.

The shape of the scrap melting chamber 17 may be a rectangular box shape, but it is preferable that the inner space of the scrap melting chamber 17 is substantially cylindrical or substantially conical in order to maintain the vortex flow from the flow generating chamber 14.

The molten metal MM containing the scrap melted in the scrap melting chamber 17 by the flowing molten metal MM and the scrap not completely melted in the scrap melting chamber 17 flows from the bottom of the scrap melting chamber 17 to the ingot charging chamber 11 through the eighth transport path W8.

Therefore, the molten metal MM containing scrap that has not been completely melted flows into the ingot charging chamber 11 from the scrap melting chamber 17 . Incompletely melted scrap has a low specific gravity and a large surface area, and may float on the surface of the molten metal MM in the ingot charging chamber 11 . In order to prevent this floating, for example, a plate-like screen plate for dissolving metal having a large number of through-holes as described in Japanese Patent No. 6829491 owned by the present applicant is preferably placed in the molten metal MM of the ingot charging chamber 11 so that the scrap having a small specific gravity is not floated to the surface of the molten metal until it is melted to a predetermined size, and is held in the area below the screen plate for dissolving metal.

Although not shown in FIG. 4, if the installation area of the molten metal furnace 1 is allowed to increase, a residue removal chamber 15 as shown in FIG. 1 can be provided between the scrap melting chamber 17 and the ingot charging chamber 11 in FIG. This is because by providing the residue removing chamber 15, the residue in the molten metal MM can be removed, and as a result, a clean molten metal MM can be obtained. However, as described above, the frequency of removal of residue is low, so the configuration of FIG. 4 is practical. Residues in the molten metal MM can be removed by scooping the residues with a ladle even in the facilities such as the ingot charging chamber 11, the return charging chamber 12, the metal melting chamber 13, and the like. Also, instead of scooping the residue with a ladle, it is also possible to pre-spread powdered metal-dissolving flux in the equipment to prevent residue from forming.

FIG. 5 shows the metal melting chamber 13 according to the second embodiment. The metal melting chamber 13 shown in FIG. 5 is not limited to use in the metal melting furnace 1 of the second embodiment, and can also be used in other metal melting furnaces 1 such as the first embodiment. Similarly, the metal melting chamber 13 shown in FIG. 2 is not limited to use in the metal melting furnace 1 of the first embodiment, and can also be used in other metal melting furnaces 1 such as the second embodiment.

Since the metal melting chamber 13 of FIG. 5 is substantially the same as the metal melting chamber 13 of FIG. 2, the description of the same parts will be omitted and only the different parts will be described. The metal melting chamber 13 of FIG. 5 is characterized in that the lower surface 13Cb of the lid portion 13C covering the metal melting chamber 13 is inclined. Specifically, the lower surface 13Cb of the lid portion 13C located above the molten metal heater 2 is inclined in the same direction as the molten metal heater 2 while leaving a predetermined gap therebetween. This point will be described in detail below.

In the example of FIG. 5, a portion of the lower surface 13Cb of the lid portion 13C that covers the metal melting chamber 13 is slanted downward from the left side to the right side of the drawing, similarly to the molten metal heater 2 . Below, the lower surface 13Cb of the lid portion 13C that is inclined in substantially the same direction as the molten metal heater 2 is referred to as the same direction inclined lower surface 13Cb1, and the lower surface 13Cb of the lid portion 13C that is inclined in a direction different from that of the molten metal heater 2 is referred to as the different direction inclination or horizontal lower surface 13Cb2. The inclination angle θ of the same-direction inclined lower surface 13Cb1 (the depression angle θ between the extension line 13Cx of the same-direction inclined lower surface 13Cb1 and the imaginary horizontal line 13Cy) is preferably substantially the same as the inclination angle α of the molten metal heater 2. For example, when the inclination angle α of the molten metal heater 2 is 35 degrees, the inclination angle θ of the same-direction inclined lower surface 13Cb1 is preferably about 33 to 37 degrees, and most preferably 35 degrees. By aligning the respective inclination angles α and θ described above, the same-direction inclined lower surface 13Cb1 of the molten metal heater 2 and the lid portion 13C can be made substantially parallel, so the surface of the molten metal heater 2 and the same-direction inclined lower surface 13Cb1 of the lid portion 13C. As a result, heat can be uniformly transferred from the molten metal heating body 2 to the molten metal MM flowing in the space Q between the molten metal heating body 2 and the lower surface 13Cb1 of the lid portion 13C inclined in the same direction. Therefore, it is possible to prevent the ingot that has not been completely melted in the ingot charging chamber 11, the return material that has not been completely melted in the return material charging chamber 12, and the scrap that has not been completely melted in the scrap melting chamber 17 from remaining unmelted. I can. That is, the space Q between the surface of the molten metal heater 2 and the lower surface 13Cb1 inclined in the same direction of the lid portion 13C can be called an easy-melting space Q, like the easy-melting space Y described above. By providing the easy-melting space Q, the ingot that was not completely melted in the ingot charging chamber 11, the return material that was not completely melted in the return material charging chamber 12, and the scrap that was not completely melted in the scrap melting chamber 17 are easily melted. The easy-melting space Q located above the molten metal heater 2 is referred to as an upper easy-melting space Q, and the easy-melting space Y located below the molten-metal heater 2 is referred to as a lower easy-melting space Y.

Further, when the same-direction inclined lower surface 13Cb1 is provided on the lid portion 13C as shown in FIG. 5, the distance P from the surface of the molten metal heater 2 to the same-direction inclined lower surface 13Cb1 is preferably 7 to 13 cm, and more preferably 10 to 11 cm. If the distance P is shorter than 7 cm, the easy-melting space Q becomes too small, so the amount of the molten metal MM flowing in the easy-melting space Q per unit time is reduced. As a result, the melting speed of the ingot that has not been completely melted in the ingot charging chamber 11 in the metal melting chamber 13, the return material that has not been completely melted in the return material charging chamber 12, and the scrap that has not been completely melted in the scrap melting chamber 17 may decrease. On the other hand, if the distance P is longer than 13 cm, the easy-melting space Q becomes too large, making it difficult to raise the temperature of the easy-melting space Q. As a result, the melting speed of the ingot that has not been completely melted in the ingot charging chamber 11 in the metal melting chamber 13, the return material that has not been completely melted in the return material charging chamber 12, and the scrap that has not been completely melted in the scrap melting chamber 17 may slow down. In addition, since the speed of the molten metal MM flowing through the easy-melting space Q does not increase, the amount of the molten metal MM in contact with the surface of the molten-metal heating element 2 on the easy-melting space Q side is reduced, so that the heat from the molten-metal heating element 2 becomes difficult to transfer to the molten metal MM, and there is a possibility that the temperature of the molten metal MM cannot be increased.

(Comparative example)
FIG. 7 shows a metal melting chamber 13 according to a comparative example. This comparative example of FIG. 7 is shown to explain the effects of the configurations of FIGS. 2 and 5 in comparison with the embodiments of FIGS. 2 and 5, and does not represent the conventionally known metal melting chamber 13.

The molten metal may be aluminum or an aluminum alloy, or other molten metal MM.

The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. For example, the metal molten metal furnace 1 of the present invention can be employed as a melting and holding furnace, a melting furnace, a holding furnace, a low-pressure casting furnace, and the like.

1 Molten metal furnace 2 Molten metal heating element 2x Molten metal heating element axis line 2y (Molten metal heating element) Virtual horizontal line 4 Flow generator 4A Motor 4Aa Rotation shaft (of motor) 4B Rotation shaft 4Ba Driven shaft 4Bb Output shaft 4C Stirring blade 4Ga Gear (attached to output shaft) 4Gb Gear (attached to rotation shaft of motor) 4V Belt 11 Ingot charging chamber 12 Return material charging chamber 13 Metal melting chamber 13C Lid 13Ca Opening (of lid) 13Cb Lower surface of lid 13Cb1 Lower surface inclined in the same direction 13Cb2 Lower surface inclined in the opposite direction or horizontal 13Cx Extension of the lower surface inclined in the same direction 13Cy Imaginary horizontal line (lower surface inclined in the same direction) 13D Metal melting chamber container 13D b... Floor portion (of metal melting chamber container) 13Db1... Inclined floor surface 13Db2... Side extending surface 13Db3... Groove portion 13Dx... Extension line of inclined floor surface 13Ds... Side wall (of metal melting chamber container) 13Dy... Imaginary horizontal line (of inclined floor surface) 13E... Heat insulating material 14... Flow generation chamber 14A... Molten metal supply port 14B... Molten metal discharge port 14C Lid (of flow generation chamber) 14D Vessel (of flow generation chamber) 15 Residue removal chamber 16 Dispensing chamber 17 Scrap melting chamber AR Space between lower surface of lid and oil surface of molten metal ML Surface MM Molten metal MR Circulation direction of molten metal OT Rotational direction P Distance between upper surface of molten metal heater and lower surface of lid inclined in the same direction Q Easy melting space (upper easy melting space) W1 First conveying path W2 Second second conveying W3 Third conveying path W4 Fourth conveying path W5 Fifth conveying path W6 Sixth conveying path W7 Seventh conveying path W8 Eighth conveying path W9 Ninth conveying path X Distance between the lower surface of the molten metal heater and the inclined floor surface Y Easy melting space (lower easy melting space) Inclination angle of the molten metal heater β Inclined floor surface θ: inclination angle of lower surface inclined in the same direction, DD: depth direction, FS: front side, BS: rear side, HD: height direction, DS: lower side (lower side), US: upper side (upper side), WD: width direction, LS: left side, RS: right side

Claims (4)

A metal melting furnace comprising a metal melting chamber containing molten metal and performing at least one of melting a metal material in the flowing molten metal and raising the temperature of the molten metal,
An elongated molten metal heater for heating the molten metal is provided inside the metal melting chamber,
The molten metal heater is provided to extend downward from a side wall portion of the metal melting chamber,
The bottom surface of the metal melting chamber located below the molten metal heater has an inclined floor surface that is inclined in the same direction as the molten metal heater while maintaining a predetermined gap from the molten metal heater,
An easy melting space is formed between the surface of the molten metal heating element and the inclined floor surface,
The molten metal furnace is characterized in that heat of the molten metal heating body is transmitted to the molten metal by the molten metal flowing in the easy-melting space coming into contact with the surface of the molten metal heating body. The bottom surface of the metal melting chamber is
the inclined floor surface positioned below the molten metal heating body and inclined substantially parallel to the molten metal heating body;
a laterally extending surface extending laterally from the lower end of the inclined floor ;
Above the laterally extending surface is a waste material accumulation portion where waste materials contained in the molten metal are accumulated,
2. The molten metal furnace according to claim 1, wherein the inclination angle of said molten metal heater and the inclination angle of said inclined floor are both within a range of 20 to 45 degrees. A lid is provided on the upper part of the metal melting chamber to cover the metal melting chamber,
2. The metal melting furnace according to claim 1 , wherein the lower surface of the portion of the lid portion of the metal melting chamber positioned above the molten metal heater is inclined in the same direction as the molten metal heater while maintaining a predetermined gap from the previous molten metal heater. A metal melting furnace comprising a metal melting chamber containing molten metal and performing at least one of melting a metal material in the flowing molten metal and raising the temperature of the molten metal,
An elongated molten metal heater for heating the molten metal is provided inside the metal melting chamber,
The molten metal heater is provided to extend downward from a side wall portion of the metal melting chamber,
A lid is provided on the upper part of the metal melting chamber to cover the metal melting chamber,
A metal melting furnace , wherein a lower surface of a portion of the lid portion of the metal melting chamber located above the molten metal heater is inclined in the same direction as the molten metal heater while maintaining a predetermined gap from the previous molten metal heater.

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