Melt holding furnace

Abstract

The invention provides a melt holding furnace. The present invention addresses the problem of, when holding a molten metal (MM) in a molten metal holding furnace (1), efficiently heating the molten metal (MM) and suppressing the generation of metal oxides and bubbles that release hydrogen gas. This molten metal holding furnace (1) is provided with a holding chamber (13) for accommodating molten metal (MM) and holding the molten metal (MM), a liquid receiving chamber (11), and a liquid discharge chamber (16), and is characterized in that the inside of the holding chamber (13) is provided with an elongated molten metal heating body (2) for heating the molten metal (MM), and the molten metal heating body (2) is provided so as to extend downward (DS) from a side wall section (13Ds) of the holding chamber (13). The bottom surface (13Db1) of the holding chamber (13), which is positioned below the melt heating body (2), is separated from the melt heating body (2) by a predetermined distance and is inclined in the same direction as the melt heating body (2).

Description

Technical Field

[0001] The present invention relates to a molten metal holding furnace for holding molten metal obtained by melting non-ferrous metal such as aluminum and aluminum alloy. Background Art

[0002] In order to heat and hold molten metal of non-ferrous metals such as aluminum and aluminum alloys, a molten metal holding furnace has been conventionally used.

[0003] Patent document 1 discloses a melting and holding furnace, which has the following parts: an immersion burner, which is installed on the top of the furnace body of the melting and holding furnace via a support plate; an inclusion floating separation device, which is arranged at a position downstream of the immersion burner and is used to float inclusions in the molten metal to the upper part of the molten metal and separate them; and a ceramic filter, which is used to filter out the aforementioned inclusions.

[0004] Patent document 2 discloses a melting and holding furnace, which has a melting furnace body and a material input mechanism for supplying molten metal to the melting furnace body, wherein the melting furnace body has a melting chamber, a liquid receiving chamber, a draw-out chamber, and a molten metal heating mechanism, and the melting chamber has a melting chamber cover. The material input mechanism has a liquid level sensor S in the draw-out chamber for detecting that the liquid level of the molten metal in the draw-out chamber drops to a lower limit liquid level, and the lower limit liquid level is set at a position higher than the lower surface height position of the melting chamber cover. When the liquid level sensor detects that the liquid level of the draw-out chamber drops to the lower limit liquid level, at least one of the molten metal and the metal block is supplied so that the liquid level of the draw-out chamber is always maintained at a position higher than the lower surface height position of the melting chamber cover.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 11-320083

[0006] Patent Document 2: Japanese Patent No. 6638158

[0007] After the molten metal is transferred from the metal melting furnace to the melting and holding furnace, the fluidity of the molten metal decreases with the passage of time. Therefore, it is preferable to also provide a molten metal heating body such as a burner or a heater in the melting and holding furnace.

[0008] In Patent Document 1, an immersion burner is used which is mounted on the top of a furnace body of a melting and holding furnace via a support plate.

[0009] However, the inventors of the present application have found that, in such a vertical immersion burner, the portion for heating the molten metal is not completely immersed in the molten metal, and therefore the molten metal may not be efficiently heated. Furthermore, when there is a space where air exists between the top portion and the molten metal as described in Patent Document 1, a portion of the portion for heating by the vertical immersion burner comes into contact with the space where air exists, and thus oxides may be easily attached near the liquid surface of the molten metal.

[0010] In the melt heating mechanism (immersion burner or immersion heater) of patent document 2, the portion that is configured to be heated in a state of penetrating the melting chamber cover from the top is completely immersed in the molten metal. The inventors of the present application have found that in this case, the molten metal may not be efficiently heated. For example, consider the following situation: the melt heating mechanism (immersion burner or immersion heater) is immersed in the molten metal in a melting chamber of a specific size such as a roughly cube or a roughly rectangular parallelepiped, and the melt heating mechanism (immersion burner or immersion heater) of a specific output heats the molten metal. In this case, the efficiency of heating the molten metal changes depending on how widely the melt heating mechanism (immersion burner or immersion heater) contacts the molten metal. That is, the larger the surface area of ​​the melt heating mechanism (immersion burner or immersion heater) in contact with the molten metal, the better the efficiency of heating the molten metal. Therefore, even if the configuration of Patent Document 2 is such that the heated portion that penetrates the melting chamber cover from the top is completely immersed in the molten metal, the molten metal may not be efficiently heated. In addition, the molten metal heating mechanism (immersion burner or immersion heater) of Patent Document 2 is sometimes arranged near the bottom of the melting chamber as a horizontal immersion type that penetrates the outer side wall of the melting chamber.

[0011] However, the inventors of the present application have found that when the melt heating mechanism (immersion burner or immersion heater) of the aforementioned Patent Document 2 is arranged near the bottom of the melting chamber in a state of penetrating from the outer side wall of the melting chamber as a horizontal immersion type, in the case of damage such as rupture of the ceramic tube covering the immersion burner or immersion heater, the molten metal may penetrate into each burner unit or heater box through the immersion burner or immersion heater. In addition, in the case of damage such as the above, when the melt heating mechanism (immersion burner or immersion heater) is arranged at the bottom of the melting chamber in a state of penetrating from the outer side wall of the melting chamber as a horizontal immersion type, there is the following operational problem: the melt heating mechanism (immersion burner or immersion heater) must be replaced after the molten metal is discharged to a height lower than the arrangement height of the melt heating mechanism (immersion burner or immersion heater).

[0012] Moreover, for example, in the case of a holding chamber for holding the molten metal of a molten metal holding furnace, the amorphous refractory material of the holding chamber container for holding the molten metal and the insulating material located outside the holding chamber container contain moisture in the atmosphere when they are made, and even if they are dried, the moisture cannot be completely discharged. In addition, the undischarged moisture of the amorphous refractory material forming the holding chamber container reacts with the molten metal and is introduced into the molten metal in the form of hydrogen atoms, and is released into the molten metal as bubbles of hydrogen. In addition, the undischarged moisture of the insulating material located outside the holding chamber container reacts with the molten metal through the amorphous refractory material forming the holding chamber container, is introduced into the molten metal in the form of hydrogen atoms, and is released into the molten metal as bubbles of hydrogen. These bubbles of hydrogen may cause pinholes in the cast product. At present, it is not sufficient to remove the bubbles of hydrogen using a degassing device using an inert gas (nitrogen or argon, etc.), and it is required to further suppress the bubbles of hydrogen release. Summary of the invention

[0013] Therefore, an object of the present invention is to provide a molten metal holding furnace capable of efficiently heating molten metal and suppressing the generation of oxides and bubbles that release hydrogen gas.

[0014] Means for solving the above-mentioned problems are as follows.

[0015] (First method)

[0016] A melt holding furnace, characterized in that the melt holding furnace is constructed to include: a holding chamber for holding molten metal; a holding chamber cover for closing the upper opening of the holding chamber; and an elongated melt heating body extending obliquely downward from the side wall of the holding chamber to heat the molten metal inside the holding chamber, the bottom surface of the holding chamber located below the melt heating body has an inclined bottom plate surface, which is separated from the melt heating body by a predetermined interval and inclined in the same direction as the melt heating body, an easy-to-heat space is formed between the melt heating body and the inclined bottom plate surface, and the heat of the melt heating body is transferred to the molten metal by the contact between the molten metal located in the easy-to-heat space and the surface of the melt heating body.

[0017] (Effect)

[0018] According to the first embodiment of the melt holding furnace, in the easily heatable space formed between the melt heating body and the inclined bottom surface of the holding chamber, the heat transfer efficiency from the entire melt heating body to the molten metal can be improved, and the molten metal in the holding chamber can be efficiently heated.

[0019] Furthermore, in order to accommodate the molten heating body in the existing holding chambers of roughly cubes or roughly rectangular parallelepipeds in which the molten heating body is placed vertically, the height of the holding chamber has to be increased to a certain extent. However, when the height of the holding chamber becomes higher, when a molten holding furnace and existing equipment (for example, a liquid supply device of a die-casting equipment, which has a maximum height of about 1200 mm, the same below) are provided at the same time, it is not uncommon for the height of the molten holding furnace to be higher than the aforementioned existing equipment. In the case where there is a height difference between the molten holding furnace and the existing equipment, there are problems such as large labor and poor operating efficiency in moving the molten metal from the molten holding furnace to the existing equipment. Furthermore, in the case where the existing molten heating body is placed vertically, when there is a space for air between the top and the molten metal, it may cause oxides to be easily attached and formed. In addition, there is a case where the molten heating body is not completely immersed in the molten metal, so it may not be possible to heat the molten metal efficiently. Furthermore, even in the case where the existing melt heating body is placed vertically and the heating part is completely immersed in the molten metal, it is not necessarily possible to heat the molten metal efficiently. For example, consider the following situation: the melt heating body is immersed in the molten metal in a melting chamber of a specific size such as a roughly cube or a roughly rectangular parallelepiped, and the melt heating body with a specific output heats the molten metal. In this case, the efficiency of heating the molten metal varies depending on how extensively the melt heating body contacts the molten metal. That is, the larger the surface area of ​​the melt heating body in contact with the molten metal, the better the efficiency of heating the molten metal. Therefore, even in the case where the existing melt heating body is placed vertically and the heating part is completely immersed in the molten metal, it is not necessarily possible to heat the molten metal efficiently.

[0020] In order to prevent such a problem, the following method is also considered: the height of the holding chamber is reduced and the width is expanded to form a holding chamber with the same capacity as the existing holding chamber, and a short-length and thick-diameter melt heater (in order to obtain the same degree of heating capacity as the existing melt heater, the diameter needs to be thickened) is vertically placed in the holding chamber. However, such a melt heater is a custom-made product, so it is very expensive (about 10 times the price) compared to the existing melt heater, and there is a problem of high initial cost.

[0021] On the other hand, in the conventional holding chamber of the type in which the melt heating body is placed horizontally, the width of the holding chamber must be expanded, so there is inevitably a problem that the area of ​​the bottom surface of the holding chamber becomes larger and the installation area of ​​the holding chamber becomes larger. In addition, when the melt heating body is damaged, the molten metal may invade the melt heating body from the damaged part. For example, when the melt heating body is an immersion burner, the molten metal may invade the burner unit, and when the melt heating body is an immersion heater, the molten metal may invade the heater box. In addition, when damage occurs, there is the following operational problem: the melt heating body must be replaced on the basis of discharging the molten metal to a height lower than the configuration height of the melt heating body.

[0022] In order to eliminate the above problems, in the first embodiment, a structure is adopted in which the melt heating body is extended from the side wall of the holding chamber toward obliquely downward. By adopting such a structure, the height of the holding chamber can be reduced compared with the existing holding chamber of the type in which the melt heating body is placed vertically. As a result, the problem of low operating efficiency mentioned above can be prevented from occurring. In addition, the entire melt heating body can be immersed in the molten metal. Since it extends obliquely downward compared with the vertical and horizontal placement of the existing melt heating body, the length can be increased, so the surface area of ​​the melt heating body in contact with the molten metal becomes larger, and the efficiency of heating the molten metal is improved. In addition, the formation of oxide adhesion can be prevented. Furthermore, compared with the conventional holding chamber of the type in which the melt heating body is placed horizontally, the area of ​​the bottom surface of the holding chamber can be reduced, so the installation area of ​​the holding chamber can be reduced, and even if the melt heating body is damaged, there is no need to worry about the molten metal invading the melt heating body from the damaged part, for example, when the melt heating body is an immersion burner, the molten metal invading the burner unit, and when the melt heating body is an immersion heater, the molten metal invading the heater box. Furthermore, even if damage occurs, the melt heating body can be replaced without discharging the molten metal to a height lower than the configuration height of the melt heating body. Furthermore, the holding chamber can be reduced, so as to reduce the amount of water from the amorphous refractory material forming the holding chamber container or the insulating material located outside the holding chamber container that reacts with the molten metal and is taken into the molten metal in the form of hydrogen atoms and released into the molten metal as bubbles of hydrogen gas, and the release of bubbles of hydrogen gas can be suppressed.

[0023] At the same time, in the first embodiment, an inclined bottom plate surface is provided which is spaced a predetermined distance from the melt heating body and is inclined in the same direction as the melt heating body. By providing the inclined bottom plate surface in the holding chamber in this way, the distance between the melt heating body and the inclined bottom plate surface is kept constant, and the heat transfer efficiency of the molten metal present in the gap becomes high.

[0024] (Second method)

[0025] 8. The molten metal holding furnace of claim 7, wherein the molten metal is supplied to the receiving chamber; a holding chamber connected to the receiving chamber for holding the molten metal flowing into the receiving chamber; a discharge chamber connected to the holding chamber for delivering the molten metal flowing into the holding chamber; a holding chamber cover for closing an upper opening of the holding chamber without forming a space between the holding chamber cover and the liquid level of the molten metal inside the holding chamber; and a liquid level sensor for detecting when the liquid level of the molten metal inside the discharge chamber drops to a lower limit liquid level, the lower limit liquid level being set to a height above the highest position on the lower surface of the holding chamber cover, and when it is detected that the liquid level of the molten metal inside the discharge chamber drops to the lower limit liquid level, the molten metal is supplied to the receiving chamber, and the molten metal inside the discharge chamber is discharged. The height of the liquid level is always maintained at a height above the highest position on the lower surface of the holding chamber cover, and is characterized in that the melt holding furnace is constructed as a slender melt heating body, which extends obliquely downward from the side wall of the holding chamber to heat the metal melt inside the holding chamber, and the bottom surface of the holding chamber located below the melt heating body has an inclined bottom plate surface, which is separated from the melt heating body by a prescribed interval and inclined in the same direction as the melt heating body, and an easy-to-heat space is formed between the melt heating body and the inclined bottom plate surface, and the heat of the melt heating body is transferred to the metal melt by the contact between the molten metal located in the easy-to-heat space and the surface of the melt heating body, and the position of the connecting part between the side wall of the holding chamber and the melt heating body is lower than the lower limit liquid level.

[0026] (Effect)

[0027] The same effects as those of the first aspect can be achieved. In addition to the effects of the first aspect, the following effects can be achieved.

[0028] That is, in the aforementioned Patent Document 1, it is mentioned that oxides may be generated near the immersion burner, and an inclusion floating separation device and a ceramic filter are provided to remove inclusions such as the oxides and foreign matter. When the inclusion floating separation device and the ceramic filter are provided, there are problems that the initial cost and the running cost become high and the structure of the melting and holding furnace becomes complicated.

[0029] Furthermore, the aforementioned Patent Document 2 discloses a melting and holding furnace structured to prevent the molten metal from contacting the air in order to suppress oxidation of the molten metal. Specifically, a structure is disclosed in which no space is formed between the melting chamber cover at the top of the melting and holding furnace and the liquid surface of the molten metal.

[0030] However, the melt heating body (immersion burner or immersion heater) of the aforementioned Patent Document 2 is arranged to penetrate the melting chamber cover from the top, or is arranged near the bottom of the melting chamber as a horizontal immersion type to penetrate the outer side wall of the melting chamber.

[0031] In the case of a configuration in which the melting chamber cover is penetrated from the top, the molten metal may not be efficiently heated. For example, consider the following situation: the molten metal heating mechanism (immersion burner or immersion heater) is immersed in the molten metal in a melting chamber of a specific size such as a roughly cube or a roughly rectangular parallelepiped, and the molten metal is heated by the molten metal heating mechanism (immersion burner or immersion heater) of a specific output. In this case, the efficiency of heating the molten metal varies depending on how widely the molten metal heating mechanism (immersion burner or immersion heater) contacts the molten metal. That is, the larger the surface area of ​​the molten metal heating mechanism (immersion burner or immersion heater) in contact with the molten metal, the better the efficiency of heating the molten metal. Therefore, in the case of a configuration in which the melting chamber cover is penetrated from the top, the molten metal may not be efficiently heated. Furthermore, when the immersion burner or immersion heater is arranged near the bottom of the melting chamber in a state of penetrating from the outer side wall of the melting chamber as a horizontal immersion type, when the ceramic tube covering the immersion burner or immersion heater is broken, the molten metal may penetrate into each burner unit or heater box through the immersion burner or immersion heater. Furthermore, when the immersion burner or immersion heater is arranged near the bottom of the melting chamber in a state of penetrating from the outer side wall of the melting chamber as a horizontal immersion type, when the above-mentioned damage occurs, there is the following operational problem: the molten metal must be discharged to a height lower than the arrangement height of the molten metal heating mechanism (immersion burner or immersion heater) before the replacement operation of the molten metal heating mechanism (immersion burner or immersion heater) is performed.

[0032] Therefore, in the second embodiment, a structure is adopted in which there is no space between the liquid surface of the molten metal in the holding chamber and the holding chamber cover, and this state can be always maintained, thereby preventing the occurrence of oxides due to air entering between the molten metal and the holding chamber cover.

[0033] At the same time, the position of the connection portion between the side wall of the holding chamber and the melt heating body is set to a position lower than the lower limit liquid level, so that the connection portion between the side wall of the holding chamber and the melt heating body can be set to a state where it is always immersed in the molten metal.

[0034] The connection between the second inclined melt heating element and the side wall of the holding chamber is at the highest position. The state where the connection at the highest position is always immersed in the molten metal can be said to be a state where the entire melt heating element is always immersed in the molten metal.

[0035] As described above, according to the melt holding furnace of the second aspect, the melt heating body installed in an inclined state can be prevented from coming into contact with the air, and thus the situation in which oxides are generated around the melt heating body can be prevented.

[0036] As a result, the possibility of oxides being mixed into the molten metal sent out from the melt holding furnace can be reduced, and high-quality molten metal can be supplied to subsequent equipment (for example, die casting equipment).

[0037] (Third Method)

[0038] According to the melt holding furnace of the first aspect or the second aspect, the inclination angle of the melt heating body and the inclination angle of the inclined bottom plate surface are both within a range of 20 degrees to 45 degrees.

[0039] (Effect)

[0040] By making the melt heating body substantially parallel to the inclined bottom plate surface, the distance between the surface of the melt heating body and the inclined bottom plate surface is substantially the same at any position, so that heat can be uniformly transferred from the melt heating body to the molten metal in the easy-to-heat space. As a result, the molten metal can be efficiently heated, and the situation that a part of the molten metal is insufficiently heated and the quality of the molten metal is reduced can be prevented.

[0041] Furthermore, by setting the inclination angle of the melt heating body to a range of 20 to 45 degrees, the height of the melt holding furnace can also be suppressed. When the height of the melt holding furnace can be suppressed, the height of the melt holding furnace is less likely to differ from the height of other existing equipment. As a result, the labor of moving the molten metal from the melt holding furnace to the existing equipment is reduced, and the operating efficiency can be improved.

[0042] (Fourth method)

[0043] According to the melt holding furnace of the first or second aspect, a lower surface of a portion of the holding chamber cover located above the melt heating body is spaced apart from the melt heating body by a predetermined distance and is inclined in the same direction as the melt heating body.

[0044] (Effect)

[0045] According to the melt holding furnace of the fourth aspect, the heat transfer efficiency from the melt heating body to the melt in the gap between the melt heating body and the holding chamber cover can be improved, and the melt in the holding chamber can be efficiently heated.

[0046] (Fifth method)

[0047] A melt holding furnace, characterized in that the melt holding furnace comprises: a holding chamber, which holds molten metal; a holding chamber cover, which closes the upper opening of the holding chamber; and an elongated melt heating body, which extends obliquely downward from the side wall of the holding chamber to heat the molten metal inside the holding chamber, and the lower surface of the portion of the holding chamber cover located above the melt heating body is separated from the melt heating body by a specified interval and is inclined in the same direction as the melt heating body.

[0048] (Effect)

[0049] The same effects as those of the first embodiment can be achieved.

[0050] (Sixth method)

[0051] A molten metal holding furnace, comprising: a liquid receiving chamber, to which molten metal is supplied; a holding chamber, which is connected to the liquid receiving chamber and holds the molten metal flowing in from the liquid receiving chamber; a liquid discharge chamber, which is connected to the holding chamber and delivers the molten metal flowing in from the holding chamber; a holding chamber cover, which closes the upper opening of the holding chamber without forming a space between the holding chamber cover and the liquid level of the molten metal inside the holding chamber; and a liquid level sensor, which detects when the height of the liquid level of the molten metal inside the liquid discharge chamber drops to a lower limit liquid level, the lower limit liquid level being set to a height above the highest position on the lower surface of the holding chamber cover, and when the liquid level of the molten metal inside the liquid discharge chamber is detected , wherein the molten metal is heated and cooled in the liquid receiving chamber and the heating element is provided to the liquid discharge chamber at a level higher than the highest position on the lower surface of the holding chamber cover. The molten metal holding furnace comprises an elongated molten metal heating body, which extends obliquely downward from the side wall of the holding chamber to heat the molten metal inside the holding chamber. The lower surface of a portion of the holding chamber cover located above the molten metal heating body is separated from the molten metal heating body by a predetermined interval and is inclined in the same direction as the molten metal heating body. The position of the connecting portion between the side wall of the holding chamber and the molten metal heating body is lower than the lower limit liquid level.

[0052] (Effect)

[0053] The same effects as those of the second and fourth aspects can be achieved.

[0054] (Seventh method)

[0055] According to the melt holding furnace of the fifth or sixth aspect, the inclination angle of the lower surface of the portion of the holding chamber cover located above the melt heating body and the inclination angle of the melt heating body are both within a range of 20 to 45 degrees.

[0056] (Effect)

[0057] By making the lower surface of the portion of the holding chamber cover located above the melt heating body substantially parallel to the melt heating body, the distance between the lower surface of the portion of the holding chamber cover located above the melt heating body and the melt heating body is substantially the same at any position, so that heat can be uniformly transferred from the melt heating body to the molten metal located in the easy-to-heat space. As a result, the molten metal can be efficiently heated, and the occurrence of a situation in which a part of the molten metal is insufficiently heated and the quality of the molten metal is reduced can be prevented.

[0058] Furthermore, by setting the inclination angle of the melt heating body to a range of 20 to 45 degrees, the height of the melt holding furnace can also be suppressed. When the height of the melt holding furnace can be suppressed, the height of the melt holding furnace is less likely to differ from the height of other existing equipment. As a result, the labor of moving the molten metal from the melt holding furnace to the existing equipment is reduced, and the operating efficiency can be improved.

[0059] (Eighth Method)

[0060] A melt holding furnace according to any one of the first, second, fifth and sixth modes, wherein the lower end of the base end portion of the melt heating body, which is the lower end of the base end portion of the melt heating body, is located at a position higher than the highest position in the lower surface of the holding chamber cover.

[0061] (Effect)

[0062] Even if the melt heating element is damaged and the molten metal intrudes into the melt heating element, the intruded molten metal will not exceed the lower end of the base end portion of the melt heating element.

[0063] (9th method)

[0064] In the melt holding furnace according to any one of the first aspect, the second aspect, the fifth aspect and the sixth aspect, at least a portion of the lower surface of the holding chamber cover has a structure that is recessed upward.

[0065] (Effect)

[0066] By forming at least a portion of the lower surface of the holding chamber cover in a shape that is recessed upward, a larger amount of molten metal can be retained in accordance with the space of the recessed shape.

[0067] According to the present invention, it is possible to provide a molten metal holding furnace capable of efficiently heating molten metal and suppressing the generation of oxides and bubbles that release hydrogen gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a schematic plan view showing the melt holding furnace 1 according to the first embodiment.

[0069] Figure 2 yes Figure 1 A cross-sectional view of the holding chamber 13 along line XX.

[0070] Figure 3 It is a schematic plan view showing a melt holding furnace 1 according to a second embodiment.

[0071] Figure 4 is along Figure 3 Cross-sectional view of line YY.

[0072] Figure 5 yes Figure 1 A cross-sectional view of the holding chamber 13 along the line XX according to another embodiment (third embodiment).

[0073] Figure 6 It is a cross-sectional view showing the holding chamber 13 of the comparative example.

[0074] Figure 7 The lower surface of the chamber cover is kept concave upward. Figure 3 Cross-sectional view of line YY.

[0075] Description of symbols

[0076] 1: melt holding furnace; 2: melt heating body; 2x: axis of melt heating body; 2y: imaginary horizontal line (of melt heating body); 11: liquid receiving chamber; 11D: liquid receiving chamber container; 13: holding chamber; 13C: holding chamber cover; 13Ca: opening cover; 13Ca1: opening; 13Cb: lower surface of holding chamber cover; 13Cb1: lower surface inclined in the same direction; 13Cb2: lower surface inclined in different directions or horizontal; 13Cx: extension line of lower surface inclined in the same direction; 13Cy: (same direction) 13D: holding chamber container; 13Db: bottom plate (of metal melting chamber container); 13Db1: inclined bottom plate surface; 13Db2: lateral extension surface; 13Db3: groove; 13Dx: extension line of inclined bottom plate surface; 13Ds: side wall (of metal melting chamber container); 13Dy: imaginary horizontal line (of inclined bottom plate surface); 13E: insulation material; 13F: contact portion; 13Ft: upper end contact portion; 14F: base end portion of melt heating body; 14 Ft: lower end of the base end of the molten metal heater; 16: liquid discharge chamber; 16D: liquid discharge chamber container; 17: liquid level sensor; 17A: lower limit liquid level sensor; 17B: upper limit liquid level sensor; 20: control unit; 21: molten metal supply unit; 22: subsequent device (die casting equipment, etc.); HL: highest position on the lower surface of the holding chamber cover; L1: upper limit liquid level; L2: lower limit liquid level; ML: liquid level; MM: molten metal; P: the upper surface of the molten metal heater and the lower surface of the holding chamber cover inclined in the same direction ; Q: easy-to-heat space (easy-to-heat space above); W1: first conveying path; W2: second conveying path; X: distance between the lower surface of the melt heating body and the inclined bottom plate surface; Y: easy-to-heat space (easy-to-heat space below); α: inclination angle of the melt heating body; β: inclination angle of the inclined bottom plate surface; θ: inclination angle of the lower surface inclined in the same direction; HD: height direction; DS: lower side (lower side); US: upper side (upper side); WD: width direction; LS: left side; RS: right side. DETAILED DESCRIPTION

[0077] Hereinafter, a preferred embodiment of the melt holding furnace 1 of the present invention will be described with reference to the drawings. Note that the following description and drawings merely illustrate an example of the embodiment of the present invention, and the content of the present invention should not be construed as being limited to the embodiment.

[0078] (First Embodiment)

[0079] exist Figure 1-21 shows a first embodiment of a melt holding furnace 1 of the present invention. The melt holding furnace 1 comprises: a liquid receiving chamber 11 for receiving a molten metal MM such as an aluminum alloy; a holding chamber 13 for holding the molten metal; and a liquid discharge chamber 16 for delivering the molten metal MM. The holding chamber 13 is provided with a melt heating body 2. A holding chamber cover 13C is provided above the holding chamber 13 US to close the upper opening of the holding chamber 13.

[0080] (Holding Room 13)

[0081] The holding chamber 13 is a space inside a holding chamber container 13D, and the molten metal MM is held in the holding chamber 13. In order to prevent the temperature of the molten metal MM in the holding chamber 13 from decreasing, a molten metal heating body 2 is provided.

[0082] The melt heating element 2 is not particularly limited, but preferably does not hinder the movement of the molten metal MM, and is preferably a slender heating element compared to a plate-shaped heating element. Specifically, it is preferred to use a tubular heating element such as a tube burner or a tube heater. There is no particular limitation on the number of melt heating elements 2 as long as the temperature of the molten metal MM can be appropriately maintained. Figure 1 In the first embodiment shown, three melt heating bodies 2 are arranged in the holding chamber 13 .

[0083] The base end of the melt heating body 2 is provided on the side wall portion of the holding chamber 13. Figure 2 In the example, the base end of the melt heating body 2 passes through the holding chamber container 13D and the insulating material 13E and is installed on the upper part of the side wall 13Ds (the side wall on the left side in the figure) of the holding chamber container 13D and the upper part of the side wall (the side wall on the left side in the figure) of the insulating material 13E located outside the holding chamber container 13D. In addition, the melt heating body 2 extends from the side wall portion of the holding chamber 13 toward the oblique downward direction of the holding chamber 13. Figure 2 In the example of , the melt heating body 2 is extended from the upper part of the side wall 13Ds (the side wall on the left side in the figure) of the holding chamber container 13D toward the bottom plate portion 13Db on the opposite side (the bottom plate portion on the right side in the figure). That is, it can also be said that the melt heating body 2 is extended from the upper part of the side wall 13Ds (the side wall on the left side in the figure) of the holding chamber container 13D toward the lower part of the side wall 13Ds (the side wall on the right side in the figure) on the opposite side.

[0084] The inclination angle of the melt heating body 2 can be set arbitrarily, but the depression angle α between the axis 2x of the melt heating body 2 and the virtual horizontal line 2y is preferably set to 20 to 45 degrees, more preferably 30 to 40 degrees.

[0085] When the angle α is less than 20 degrees, the height of the holding chamber 13 can be suppressed. As a result, there is an advantage that the above-mentioned inconvenience of lowering the operating efficiency of the conventional equipment can be prevented from occurring.

[0086] However, if the height of the holding chamber 13 is too low, it is necessary to change the heights of the liquid receiving chamber 11 and the liquid discharging chamber 16. That is, if the heights of the liquid receiving chamber 11 and the liquid discharging chamber 16 are not changed, the heights of the chambers 11, 13, and 16 will be greatly different, so the following undesirable situation will occur: the shapes of the conveying paths (first conveying path W1 and second conveying path W2) of the liquid receiving chamber 11 and the liquid discharging chamber 16 connected to the holding chamber 13 are deformed, and the molten metal MM is difficult to flow between the chambers 11, 13, and 16.

[0087] Furthermore, there is no need to excessively reduce the angle α of the melt heating body 2.

[0088] Furthermore, as the angle α of the melt heating body 2 decreases, the extending direction of the melt heating body 2 approaches horizontality, and therefore the width of the holding chamber 13 needs to be increased to accommodate the melt heating body 2. As a result, a larger space is required for installing the holding chamber 13.

[0089] Furthermore, when the width of the holding chamber 13 increases, the area of ​​the bottom surface of the holding chamber 13 tends to increase. When the area of ​​the bottom surface of the holding chamber 13 is large, there are also disadvantages such as increased heat dissipation and increased installation area.

[0090] Based on the above, the angle α of the melt heating body 2 is preferably greater than or equal to 20 degrees.

[0091] On the other hand, when the angle α is larger than 45 degrees, the height of the holding chamber 13 for accommodating the melt heating body 2 cannot be suppressed, and there is a possibility that the operating efficiency of the conventional equipment or the like is reduced as described above.

[0092] Since there are operational inconveniences as described above, the angle α is preferably equal to or smaller than 45 degrees.

[0093] exist Figure 2In the example, the left and right side walls 13Ds of the holding chamber container 13D are approximately vertical, and the bottom plate portion 13Db on the right side of the figure is approximately horizontal. On the other hand, the bottom plate portion 13Db on the left side of the figure of the holding chamber container 13D is inclined downward from the left side of the figure to the right side, similarly to the aforementioned melt heating body 2. The inclination angle β of the inclined bottom plate surface 13Db1 of the bottom plate portion 13Db of the holding chamber container 13D (the angle β of the depression angle between the extension line 13Dx of the inclined bottom plate surface 13Db1 and the imaginary horizontal line 13Dy) is preferably approximately the same as the inclination angle α of the aforementioned melt heating body 2. For example, when the inclination angle α of the melt heating body 2 is 35 degrees, the inclination angle β of the inclined bottom plate surface 13Db1 is also preferably about 33 to 37 degrees, and most preferably 35 degrees. By making the aforementioned inclination angles α and β consistent, the melt heating body 2 can be made substantially parallel to the inclined bottom plate surface 13Db1, so that the distance X (the distance in the direction perpendicular to the axis 2x of the melt heating body 2) between the surface of the melt heating body 2 and the bottom plate portion 13Db (inclined bottom plate surface 13Db1) is substantially the same at any position. As a result, heat can be uniformly transferred from the melt heating body 2 to the molten metal MM in the space Y between the melt heating body 2 and the inclined bottom plate surface 13Db1, so that the molten metal MM can be uniformly heated.

[0094] That is, the closer to the melt heating body 2 as the heat generating source, the easier the molten metal MM is to be heated. In particular, in the space Y between the surface of the melt heating body 2 and the inclined bottom plate surface 13Db1, the heat generated from the melt heating body 2 hits the inclined bottom plate surface 13Db1 and is reflected, and returns to the melt heating body 2 again, so the heating efficiency is improved. In addition, by making the distance X between the outer surface of the melt heating body 2 and the inclined bottom plate surface 13Db1 substantially the same at any position in the axial direction of the melt heating body 2, the temperature of the space Y is substantially the same at any position, so that temperature unevenness is not likely to occur in the space Y.

[0095] and, Figure 2 The holding chamber 13 shown is Figure 6 Compared with the case where the bottom plate 13Db of the holding chamber 13 is not inclined as shown, the distance X from the melt heating body 2 to the bottom plate 13Db below it is shortened. Figure 6 Compared with the method shown, Figure 2 The embodiment shown makes it easier to heat the molten metal MM in the space Y. In addition, Figure 2 The holding chamber 13 shown is Figure 6The holding chamber 13 shown is small, so the amount of moisture from the amorphous refractory material forming the holding chamber container 13D or the insulating material 13E located outside the holding chamber container 13D reacts with the molten metal MM and is introduced into the molten metal MM in the form of hydrogen atoms and released into the molten metal MM as hydrogen bubbles also decreases, which inevitably suppresses the release of hydrogen bubbles.

[0096] In the image Figure 2 In the case where the holding chamber container 13D is provided with the inclined bottom plate surface 13Db1, the distance X from the surface of the melt heating body 2 to the inclined bottom plate surface 13Db1 is preferably 7 cm to 13 cm, and more preferably 10 cm to 11 cm. When the distance X is shorter than 7 cm, the space Y is too small, so the amount of the molten metal MM in the space Y is reduced, and as a result, the temperature unevenness in the holding chamber 13 may become larger. On the other hand, when the distance X is longer than 13 cm, the space Y is too large, so the amount of the molten metal MM in the space Y is increased, which may cause undesirable phenomena such as reduced heating efficiency.

[0097] In addition, Figure 6 In the comparative example shown, to be precise, the distance from the melt heating body 2 to the bottom plate 13Db thereunder varies greatly. In such a case, the distance X is the average distance from the melt heating body 2 to the bottom plate 13Db thereunder.

[0098] like Figure 2 Thus, the bottom plate 13Db of the holding chamber container 13D has a side extension surface 13Db2 extending laterally from the lower end of the inclined bottom plate surface 13Db1. The side extension surface 13Db2 extends substantially horizontally in the lateral direction from the lower end of the inclined bottom plate surface 13Db1.

[0099] In the holding chamber 13 , when foreign matter (hereinafter referred to as “waste matter” as unnecessary matter) exists in the molten metal MM, the foreign matter gradually accumulates on the bottom plate 13Db of the holding chamber 13 due to gravity as time passes.

[0100] like Figure 2 In this way, by providing an inclined bottom plate surface 13Db1 on the bottom plate portion 13Db of the holding chamber 13, useless objects that fall onto the inclined bottom plate surface 13Db1 roll down along the inclination of the inclined bottom plate surface 13Db1 and stay on the side extension surface 13Db2. That is, the useless objects are not dispersed on the entire bottom surface of the holding chamber 13, but are naturally concentrated on the side extension surface 13Db2. Therefore, when opening the opening cover 13Ca provided on the holding chamber cover 13C is opened, and a handle ladle or the like is inserted into the holding chamber 13 from the opening 13Ca1 to scoop up and recover the useless objects, it is sufficient to scoop up the useless objects accumulated on the side extension surface 13Db2, so it is similar to the above. Figure 6Compared with the case where the inclined bottom surface 13Db1 is not provided, the waste materials are not scattered, so the efficiency of collecting the waste materials can be improved.

[0101] And, if Figure 1 , Figure 2 As shown, a recessed portion (groove 13Db3) may be provided on the side extension surface 13Db2. By providing such a groove 13Db3, when collecting waste, the waste on the side extension surface 13Db2 falls into the groove 13Db3, and then the handle ladle is placed inside the groove 13Db3 and moved along the extension direction of the groove 13Db3, so that the waste can be collected more easily.

[0102] The opening portion 13Ca1 of the retaining chamber cover 13C has an inner peripheral surface that is set to gradually increase the opening area toward the upper side and is inclined. The opening portion cover 13Ca has an outer peripheral surface that is inclined corresponding to the inner peripheral surface of the opening portion 13Ca1 in a manner that allows the opening portion 13Ca1 to be inserted from the upper side. Therefore, compared with the case where the inner peripheral surface and the outer peripheral surface are perpendicular, it is not easy to form a gap during insertion, oxidation is prevented, and the opening portion 13Ca1 can be easily closed only by inserting the opening portion cover 13Ca1 into the opening portion 13Ca1 from the upper side. In addition, when the opening portion cover 13Ca is picked up and removed during maintenance, the opening portion cover 13Ca can be prevented from falling to the bottom of the retaining chamber 13. In addition, by inserting the opening portion cover 13Ca into the opening portion 13Ca1, the opening portion cover 13Ca functions as a part of the retaining chamber cover 13C, so the opening portion cover 13Ca can also be said to be a part of the retaining chamber cover 13C.

[0103] In addition, the space Y between the melt heating body 2 and the inclined bottom plate surface 13Db1 is also referred to as an easy-to-heat space, in accordance with the meaning of a space that is easy to heat the molten metal MM. Since the amount of the molten metal MM present in this easy-to-heat space is small, the heat of the melt heating body 2 is transferred to the molten metal MM by the contact between the molten metal MM and the surface of the melt heating body 2, and the molten metal MM is easily heated.

[0104] (Second Embodiment)

[0105] exist Figure 3 and Figure 4 2 shows a second embodiment of the melt holding furnace 1 according to the present invention.

[0106] The molten metal holding furnace 1 comprises: a liquid receiving chamber 11 for receiving a molten metal MM such as an aluminum alloy; a holding chamber 13 for holding the molten metal MM; and a liquid discharge chamber 16 for delivering the molten metal MM. In the following description, the same parts as those of the first embodiment, such as the structure of the holding chamber 13 and the method for installing the molten metal heating body 2, are omitted.

[0107] A holding chamber cover 13C is provided at the upper portion US of the holding chamber 13 . The holding chamber cover 13C closes the upper opening of the holding chamber 13 so that no space is formed between the holding chamber cover 13C and the liquid surface of the molten metal MM in the holding chamber 13 .

[0108] like Figure 4 As shown, the liquid discharge chamber 16 is equipped with a lower limit liquid level sensor 17A for detecting the situation of falling to the lower limit liquid level L2, which is set to a height above the highest position HL on the lower surface of the holding chamber cover 13C of the holding chamber 13. The lower limit liquid level sensor 17A is used to detect the situation that the liquid level of the molten metal MM in the liquid discharge chamber 16 is approaching the lower limit liquid level L2 (or / and reaching the lower limit liquid level L2). Then, the information that the liquid level of the molten metal MM in the liquid discharge chamber 16 is approaching the lower limit liquid level L2 (or / and reaching the lower limit liquid level L2) is transmitted to the control unit 20. The control unit 20 that receives the information determines whether to supply new molten metal MM to the liquid receiving chamber 11, and determines the amount of molten metal MM to be supplied if it is supplied. If it is determined that the molten metal MM is supplied, an instruction is issued to the molten metal supply unit 21, and the molten metal supply unit 21 supplies the molten metal MM of the amount of the received instruction to the liquid receiving chamber 11. In addition, as the molten metal supply unit 21, for example, a known conveying mechanism can be used, such as one that uses a liquid guide groove to allow the molten metal MM to flow from a melting furnace located at a remote location into the liquid receiving chamber 11.

[0109] By supplying the molten metal MM to the receiving chamber 11, a portion of the molten metal MM in the receiving chamber 11 flows to the holding chamber 13 via the first conveying path W1, and a portion of the molten metal MM in the holding chamber 13 flows to the discharge chamber 16 via the second conveying path W2. As a result, the liquid level in the discharge chamber 16 rises.

[0110] Similarly, by taking out (sending) the molten metal MM from the liquid discharge chamber 16, a portion of the molten metal MM in the liquid receiving chamber 11 flows to the holding chamber 13 via the first conveying path W1, and a portion of the molten metal MM in the holding chamber 13 flows to the liquid discharge chamber 16 via the second conveying path W2. As a result, the liquid level of the liquid receiving chamber 11 is lowered.

[0111] As described above, by supplying the molten metal MM to the receiving chamber 11 or taking the molten metal MM out from the discharging chamber 16 , a flow of the molten metal MM is generated inside each of the receiving chamber 11 , the holding chamber 13 , and the discharging chamber 16 .

[0112] Furthermore, since the liquid receiving chamber 11 , the holding chamber 13 , and the liquid discharge chamber 16 are connected to each other via the first conveying path W1 and the second conveying path W2 , the liquid levels in the liquid receiving chamber 11 , the holding chamber 13 , and the liquid discharge chamber 16 are always substantially at the same height.

[0113] By means of the above mechanism, the height of the liquid level of the liquid discharge chamber 16 can be maintained at a height position higher than the highest position HL on the lower surface of the holding chamber cover 13C. Therefore, there is always no space between the liquid level of the molten metal MM in the holding chamber 13 and the holding chamber cover 13C, and the molten metal MM in the holding chamber 13 can be prevented from contacting the air. If the molten metal MM contacts the air, it will cause the generation of metal oxides, but by adopting the structure of this embodiment, the generation of metal oxides can be prevented.

[0114] And, with Figure 2 Similarly to the state shown, inside the holding chamber 13, the entire melt heating body 2 is always immersed in the molten metal MM. That is, inside the holding chamber 13, in the melt heating body 2, the contact portion 13F (more specifically, the upper end of the contact portion 13F (referred to as "upper end contact portion 13Ft")) between the inner surface of the side wall 13Ds of the holding chamber container 13D and the melt heating body 2 is the highest portion. The height of the upper end contact portion 13Ft is a height below the aforementioned lower limit liquid level L2, so the upper end contact portion 13Ft is always immersed in the molten metal MM in the holding chamber 13. Moreover, in the holding chamber 13, other portions other than the upper end contact portion 13Ft of the melt heating body 2 are located at a lower position than the upper end contact portion 13Ft, so other portions are also always immersed in the molten metal MM in the holding chamber 13.

[0115] Therefore, the melt heating body 2, which is set in a state of being inclined downward, can be prevented from contacting the air, so it is possible to prevent the occurrence of oxides around the melt heating body 2. As a result, the possibility of oxides being mixed into the molten metal MM sent out from the melt holding furnace 1 can be reduced, and high-quality molten metal MM can be provided to the subsequent device (for example, die casting equipment).

[0116] Furthermore, inside the holding chamber 13, if the melt heating body 2 is in contact with the air, the melt heating body 2 will also heat the air, so the heating efficiency of the melt heating body 2 may be reduced. However, in the second embodiment (and the first embodiment), the melt heating body 2 is always immersed in the molten metal MM in its entirety in the holding chamber 13, and the portion (air) where the molten metal MM does not exist is not heated, so the molten metal MM can be efficiently heated.

[0117] In addition, if Figure 3 , Figure 4As shown in FIG. 1 , in order to prevent the temperature of the molten metal MM in the discharge chamber 16 from decreasing, it is preferable to also provide a melt heating body 2 such as a heater inside the discharge chamber 16. In this case, the shape of the melt heating body 2 and the bottom surface of the discharge chamber 16 may be the same as that of the melt heating body 2 and the holding chamber container 13D in the holding chamber 13. That is, when the heating efficiency of the melt heating body 2 is emphasized in the discharge chamber 16, the melt heating body 2 is preferably arranged at a lower temperature than that of the holding chamber 13D. Figure 2 Similarly to the method shown in the figure, preferably, the melt heating body 2 is also arranged in the liquid discharge chamber 16 to extend obliquely downward from the side wall of the liquid discharge chamber 16, and the bottom surface of the liquid discharge chamber 16 located below the melt heating body 2 is also set to be an inclined bottom plate surface inclined in the same direction as the melt heating body 2 in a manner substantially parallel to the melt heating body 2. In this case, an easy-to-heat space is formed between the inclined bottom plate surface of the liquid discharge chamber 16 and the melt heating body 2, and the heat of the melt heating body 2 is transferred to the metal melt MM by the contact between the molten metal MM located in the easy-to-heat space and the surface of the melt heating body 2.

[0118] The liquid outlet chamber 16 may also be equipped with an upper limit liquid level sensor 17B. Figure 4 As shown, in addition to the lower limit liquid level sensor 17A for detecting the lower limit liquid level L2, an upper limit liquid level sensor 17B for detecting the upper limit liquid level L1 is also provided, wherein the lower limit liquid level L2 is set to a height above the highest position HL on the lower surface of the holding chamber cover 13C, and the upper limit liquid level L1 is set at a position above the lower limit liquid level L2.

[0119] The lower limit level sensor 17A may be at the same height as the highest position HL on the lower surface of the holding chamber cover 13C, but is preferably higher than this. The level sensor 17 may be an integrated upper limit level sensor 17B and lower limit level sensor 17A.

[0120] When the lower limit liquid level sensor 17A detects the liquid level, it is transmitted to the control unit 20. The control unit 20 that receives the information determines whether to supply new molten metal MM to the liquid receiving chamber 11, and determines to what extent the molten metal MM is supplied if it is supplied. When it is determined that the molten metal MM is supplied, an instruction is issued to the molten metal supply unit 21, and the molten metal supply unit 21 supplies the molten metal MM in the amount of the received instruction to the liquid receiving chamber 11. As a result, the liquid level height position of the liquid discharge chamber 16 is maintained at a position always higher than the highest position HL on the lower surface of the holding chamber cover 13C, so that the molten metal MM does not contact the air in the holding chamber 13, and oxidation of the molten metal MM can be prevented.

[0121] Furthermore, when the upper limit liquid level sensor 17B detects the liquid level, it is transmitted to the control unit 20. The control unit 20 receiving the information issues a command to the molten metal supply unit 21, and the molten metal supply unit 21 stops supplying the molten metal MM. Therefore, it is possible to prevent the molten metal MM from being excessively supplied to the molten metal holding furnace 1.

[0122] (Third Embodiment)

[0123] exist Figure 5 It is shown in Figure 2 A holding chamber 13 (third embodiment) is provided in a different manner. Figure 5 The holding chamber 13 shown is Figure 2 The holding chamber 13 of the embodiment can be similarly used in the melt holding furnace 1 of the first embodiment and the second embodiment.

[0124] Figure 5 The holding chamber 13 and Figure 2 The holding chamber 13 is substantially the same, and therefore description of the same parts will be omitted, and only the different parts will be described. Figure 5 The holding chamber 13 is characterized in that the lower surface 13Cb of the holding chamber cover 13C covering the holding chamber 13 is inclined. Specifically, the lower surface 13Cb of the holding chamber cover 13C located above the melt heating body 2 is separated from the melt heating body 2 by a predetermined interval and is inclined in the same direction as the melt heating body 2. This point will be described in detail below.

[0125] exist Figure 5In the example, a portion of the lower surface 13Cb of the holding chamber cover 13C covering the holding chamber 13 is inclined downward from the left side to the right side in the figure, similarly to the melt heating body 2. Hereinafter, the lower surface 13Cb of the holding chamber cover 13C inclined in approximately the same direction as the melt heating body 2 is referred to as the same-direction inclined lower surface 13Cb1, and the lower surface 13Cb of the holding chamber cover 13C inclined in a different direction from the melt heating body 2 is referred to as the different-direction inclined or horizontal lower surface 13Cb2. The inclination angle θ of the same-direction inclined lower surface 13Cb1 (the angle θ of depression 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 aforementioned melt heating body 2. For example, when the inclination angle α of the melt heating body 2 is 35 degrees, the inclination angle θ of the same-direction inclined lower surface 13Cb1 is preferably also about 33 to 37 degrees, and most preferably 35 degrees. By making the aforementioned inclination angles α and θ consistent, the melt heating body 2 can be made substantially parallel to the lower surface 13Cb1 of the holding chamber cover 13C that is inclined in the same direction, so that the distance P between the surface of the melt heating body 2 and the lower surface 13Cb1 of the holding chamber cover 13C that is inclined in the same direction (the distance in the direction perpendicular to the axis 2x of the melt heating body 2) is substantially the same at any position. As a result, heat can be uniformly transferred from the melt heating body 2 to the molten metal MM flowing in the space Q between the melt heating body 2 and the lower surface 13Cb1 of the holding chamber cover 13C that is inclined in the same direction, so that the temperature unevenness of the molten metal MM can be reduced, and efficient heating can be performed. That is, the space Q between the surface of the melt heating body 2 and the lower surface 13Cb1 of the holding chamber cover 13C that is inclined in the same direction can play the same effect as the aforementioned space Y. By providing this space Q, the temperature unevenness of the molten metal MM is reduced, and the effect of enabling efficient heating is the same as that of the easy-to-heat space Y, so detailed description is omitted here.

[0126] And, if Figure 5 As shown, when the holding chamber cover 13C is provided with a lower surface 13Cb1 inclined in the same direction, the distance P from the surface of the melt heating body 2 to the lower surface 13Cb1 inclined in the same direction is preferably 7 cm to 13 cm, and more preferably 10 cm to 11 cm. When the distance P is shorter than 7 cm, the space Q is too small, so the amount of the molten metal MM flowing in the space Q per unit time decreases, resulting in a possibility that the temperature unevenness in the holding chamber 13 becomes larger and the heating efficiency decreases. On the other hand, when the distance P is longer than 13 cm, the speed of the molten metal MM flowing in the space Q does not increase, so the amount of the molten metal MM in contact with the surface of the melt heating body 2 on the space Q side decreases, so that the heat from the melt heating body 2 is not easily transferred to the molten metal MM, the heating efficiency of the molten metal MM decreases, and the temperature unevenness increases.

[0127] The liquid discharge chamber is provided with a lower limit liquid level sensor 17A, whereby the liquid level height position of the liquid discharge chamber 16 is maintained at a position always above the highest position HL on the lower surface of the holding chamber cover 13C. Therefore, the molten metal MM in the holding chamber 13 does not come into contact with the air, thereby preventing the molten metal MM from oxidizing.

[0128] Figure 2 and Figure 5 The highest position HL on the lower surface of the holding chamber cover 13C shown in the figure indicates the upper limit position of the molten metal MM in the holding chamber 13 and is below the lower limit liquid level L2 of the discharge chamber 16, and is preferably located below this.

[0129] In addition, the base end 14F of the melt heating body 2 (more specifically, the lower end of the base end 14F of the melt heating body (referred to as the "lower end 14Ft of the base end of the melt heating body") is located at a position higher than at least the highest position HL on the lower surface of the holding chamber cover 13C. Preferably, it is a position higher than the upper limit liquid level L1. As a result, as in the second embodiment, the height of the liquid level of the liquid discharge chamber 16 is maintained at a height position above the highest position HL on the lower surface of the holding chamber cover 13C, and a state is maintained in which there is no space between the liquid level of the molten metal MM in the holding chamber 13 and the holding chamber cover 13C. Therefore, even if the melt heating body 2 is damaged in this state and the molten metal MM invades the melt heating body 2, the invading molten metal MM will not exceed the lower end 14Ft of the base end of the melt heating body.

[0130] You can also Figure 7 As shown, at least a portion of the lower surface of the holding chamber cover 13C is in a shape that is concave upward. The central portion of the lower surface of the holding chamber cover 13C, except for the peripheral portion, may be in a shape that is concave upward. In addition, as in the fifth and sixth embodiments, when the lower surface of the portion of the holding chamber cover 13C located above the melt heating body 2 is separated from the melt heating body 2 by a predetermined interval and tilted in the same direction as the melt heating body 2, at least a portion of the lower surface of the holding chamber cover 13C other than the portion of the lower surface of the portion of the holding chamber cover 13C located above the melt heating body 2 is separated from the melt heating body 2 by a predetermined interval and tilted in the same direction as the melt heating body 2 is in a shape that is concave upward. Thus, a larger amount of molten metal can be held according to the space of the concave shape. However, the top surface of the concave shape is set to a position lower than the upper edge of the lower upper edge of at least one of the liquid receiving chamber 11 and the liquid discharge chamber 16. This is because, if the top surface is high, the molten metal MM may flow out from the upper edge of at least one of the liquid receiving chamber 11 and the liquid discharge chamber 16 , which is lower than the top surface.

[0131] (Comparative Example)

[0132] exist Figure 6 FIG. 1 shows a holding chamber 13 of a comparative example. Figure 6 The comparison example is to compare Figure 2 , Figure 5 Compare the implementation methods of Figure 2 , Figure 5 The structure is shown for the purpose of explaining the effect of the structure, and does not represent a conventionally known holding chamber 13.

[0133]

Industrial Applicability

[0134] The molten metal may be other molten metals MM other than aluminum or aluminum alloy.

[0135] In addition, the technical scope of the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the present invention. For example, the molten metal holding furnace 1 of the present invention can also be used as a melting holding furnace, a melting furnace, a low-pressure casting furnace, etc.

Claims

1. A melt holding furnace, characterized in that: The melt holding furnace is configured to include: A holding chamber that holds the molten metal; a holding chamber cover that closes an upper opening of the holding chamber; and The slender melt heating body extends obliquely downward from the side wall of the holding chamber to heat the molten metal in the holding chamber. The bottom surface of the holding chamber located below the melt heating body has an inclined bottom surface, which is spaced apart from the melt heating body by a predetermined distance and is inclined in the same direction as the melt heating body. An easy-to-heat space is formed between the melt heating body and the inclined bottom plate surface. The molten metal in the easy-to-heat space comes into contact with the surface of the molten metal heater, so that the heat of the molten metal heater is transferred to the molten metal.

2. A melt holding furnace, comprising: a receiving chamber, which is supplied with molten metal; a holding chamber, which is in communication with the liquid receiving chamber and holds the molten metal flowing into the liquid receiving chamber; a liquid outlet chamber, which is in communication with the holding chamber and delivers the molten metal flowing into the holding chamber; a holding chamber cover that closes an upper opening of the holding chamber without forming a space between the holding chamber cover and a liquid surface of the molten metal inside the holding chamber; and a liquid level sensor for detecting when the liquid level of the molten metal in the liquid discharge chamber drops to a lower limit liquid level, the lower limit liquid level being set to a height above the highest position on the lower surface of the holding chamber cover; When it is detected that the liquid level of the molten metal inside the liquid discharge chamber drops to the lower limit liquid level, the molten metal is supplied to the liquid receiving chamber, and the liquid level of the molten metal inside the liquid discharge chamber is always maintained at a height above the highest position on the lower surface of the holding chamber cover. It is characterized in that The molten metal holding furnace is configured to include an elongated molten metal heating body, which extends obliquely downward from a side wall of the holding chamber to heat the molten metal in the holding chamber. The bottom surface of the holding chamber located below the melt heating body has an inclined bottom surface, which is spaced apart from the melt heating body by a predetermined distance and is inclined in the same direction as the melt heating body. An easy-to-heat space is formed between the melt heating body and the inclined bottom plate surface. The molten metal in the easy-to-heat space contacts the surface of the molten metal heater, and the heat of the molten metal heater is transferred to the molten metal. A position of a connection portion between a side wall portion of the holding chamber and the melt heating body is lower than the lower limit liquid level.

3. The melt holding furnace according to claim 1 or 2, wherein: The inclination angle of the melt heating body and the inclination angle of the inclined bottom plate surface are both within a range of 20 degrees to 45 degrees.

4. The melt holding furnace according to claim 1 or 2, wherein: A lower surface of a portion of the holding chamber cover located above the melt heating body is spaced a predetermined distance from the melt heating body and is inclined in the same direction as the melt heating body.

5. A melt holding furnace, characterized in that: The melt holding furnace comprises: A holding chamber that holds the molten metal; a holding chamber cover that closes an upper opening of the holding chamber; and The slender melt heating body extends obliquely downward from the side wall of the holding chamber to heat the molten metal in the holding chamber. A lower surface of a portion of the holding chamber cover located above the melt heating body is spaced a predetermined distance from the melt heating body and is inclined in the same direction as the melt heating body.

6. A melt holding furnace, comprising: a receiving chamber, which is supplied with molten metal; a holding chamber, which is in communication with the liquid receiving chamber and holds the molten metal flowing into the liquid receiving chamber; a liquid outlet chamber, which is in communication with the holding chamber and delivers the molten metal flowing into the holding chamber; a holding chamber cover that closes an upper opening of the holding chamber without forming a space between the holding chamber cover and a liquid surface of the molten metal inside the holding chamber; and a liquid level sensor for detecting when the liquid level of the molten metal in the liquid discharge chamber drops to a lower limit liquid level, the lower limit liquid level being set to a height above the highest position on the lower surface of the holding chamber cover; When it is detected that the liquid level of the molten metal inside the liquid discharge chamber drops to the lower limit liquid level, the molten metal is supplied to the liquid receiving chamber, and the liquid level of the molten metal inside the liquid discharge chamber is always maintained at a height above the highest position on the lower surface of the holding chamber cover. It is characterized in that The molten metal holding furnace includes an elongated molten metal heating body extending obliquely downward from a side wall of the holding chamber to heat the molten metal in the holding chamber. The lower surface of a portion of the holding chamber cover located above the melt heating body is spaced apart from the melt heating body by a predetermined distance and is inclined in the same direction as the melt heating body. A position of a connection portion between a side wall portion of the holding chamber and the melt heating body is lower than the lower limit liquid level.

7. The melt holding furnace according to claim 5 or 6, wherein: The inclination angle of the lower surface of the portion of the holding chamber cover located above the melt heating body and the inclination angle of the melt heating body are both within a range of 20 to 45 degrees.

8. The melt holding furnace according to any one of claims 1, 2, 5 and 6, wherein: The lower end of the base end portion of the melt heating body is located at a position higher than the highest position of the lower surface of the holding chamber cover.

9. The melt holding furnace according to any one of claims 1, 2, 5 and 6, wherein: At least a portion of the lower surface of the holding chamber cover is recessed upward.

Images