Molten metal holding furnace

Abstract

To provide a molten metal holding furnace 1 in which, upon holding a molten metal MM at the inside of the molten metal holding furnace, the heating of the molten metal MM is efficiently executed, and the generation of metal oxides and the release of hydrogen gas bubbles are suppressed.SOLUTION: The molten metal holding furnace 1 comprises: a holding chamber 13 storing the molten metal MM and holding the temperature thereof; a molten metal receiving chamber 11; and a tapping chamber 16. The inside of the holding chamber 13 is provided with an elongated molten metal heating body 2 heating the molten metal MM, the molten metal heating body 2 is provided so as to extend from a side wall part 13Ds of the holding chamber 13 downstream DS, and a bottom face 13Db1 of the holding chamber 13 located downstream DS of the molten metal heating body 2 is tilted to a the same direction as that of the molten metal heating body 2 at prescribed intervals with the molten metal heating body 2.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] 2. Description of the Related Art Molten metal holding furnaces have conventionally been used to heat and hold molten metal of non-ferrous metals such as aluminum and aluminum alloys.

[0003] Patent Document 1 describes an immersion burner attached to the ceiling of a melting and holding furnace via a support plate, and formula The document discloses a melting and holding furnace equipped with an inclusion flotation separation device that is disposed downstream of a burner and that floats and separates inclusions in the molten metal to the top of the molten metal, and a ceramic filter or the like that filters out the inclusions.

[0004] Patent Document 2 discloses a melting and holding furnace that includes a melting furnace body and a material supplying mechanism for supplying molten metal to the melting furnace body, the melting furnace body including a melting chamber, a receiving chamber, a pumping chamber, and a molten metal heating mechanism, and the melting chamber including a melting chamber lid. The material supplying mechanism includes a liquid level sensor S that detects when the liquid level of the molten metal in the pumping chamber drops to a lower limit level set above the lower surface level of the melting chamber lid in the pumping chamber, and when the liquid level sensor detects that the liquid level in the pumping chamber has dropped to the lower limit level, at least one of the molten metal and the metal lump is supplied to the receiving chamber so that the liquid level in the pumping chamber is always kept above the lower surface level of the melting chamber lid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-320083 [Patent Document 2] Patent No. 6638158 Summary of the Invention [Problem to be solved by the invention]

[0006] Since the fluidity of the molten metal decreases over time after it is transferred from the metal melting furnace to the melting and holding furnace, it is preferable to provide a molten metal heating device such as a burner or heater in the melting and holding furnace.

[0007] In Patent Document 1, an immersion burner is used that is attached to the ceiling of the furnace body of a melting and holding furnace via a support plate.

[0008] However, the inventors of this application have found that such a vertical immersion burner does not necessarily heat the molten metal efficiently because the part that heats the molten metal is not entirely immersed in the molten metal. Also, if there is a space containing air between the ceiling and the molten metal as described in Patent Document 1, part of the part that heats the vertical immersion burner will come into contact with the space containing air, which may cause oxides to easily adhere to and form near the surface of the molten metal.

[0009] In the molten metal heating mechanism (submersion burner or immersion heater) of Patent Document 2, the part to be heated is entirely submerged in the molten metal while penetrating the melting chamber cover from above. The inventors of the present application have found that in this case, the molten metal is not necessarily heated efficiently. For example, consider a case where a molten metal heating mechanism (submersion burner or immersion heater) is immersed in the molten metal in a melting chamber of a specific size, such as an approximately cube or approximately rectangular parallelepiped, and the molten metal is heated by the molten metal heating mechanism (submersion burner or immersion heater) with a specific output. In this case, the efficiency of heating the molten metal changes depending on how widely the molten metal heating mechanism (submersion burner or immersion heater) comes into contact with the molten metal. In other words, the greater the surface area of ​​the molten metal heating mechanism (submersion burner or immersion heater) that comes into contact with the molten metal, the better the efficiency of heating the molten metal. Therefore, even if the melting chamber cover of Patent Document 2 is penetrated from above and the entire portion to be heated is immersed in the molten metal, it cannot necessarily be said that the molten metal is heated efficiently. Also, the molten metal heating mechanism (immersion burner or immersion heater) of Patent Document 2 may be of the horizontal immersion type and may be disposed near the bottom of the melting chamber, penetrating the outer side wall of the melting chamber.

[0010] However, the inventors of the present application found that in the horizontal immersion type arrangement of the molten metal heating mechanism (immersion burner or immersion heater) of Patent Document 2, which penetrates from the outer side wall of the melting chamber to the vicinity of the bottom of the melting chamber, if the ceramic tube covering the immersion burner or immersion heater is broken, the molten metal may infiltrate into the respective burner units and heater boxes through the immersion burner or immersion heater. In addition, in the horizontal immersion type arrangement, which penetrates from the outer side wall of the melting chamber to the vicinity of the bottom of the melting chamber, if the above-mentioned damage occurs, the molten metal must be drained to a height lower than the height of the molten metal heating mechanism (immersion burner or immersion heater), and then the molten metal heating mechanism (immersion burner or immersion heater) must be replaced, which is an operational problem.

[0011] Furthermore, for example, in the case of a holding chamber for holding the molten metal of a molten metal holding furnace, the amorphous refractory forming the holding chamber container in which the molten metal is actually held and the insulating material located outside the holding chamber container contain moisture from the atmosphere when they are manufactured, and even if they are dried, the moisture is not completely removed. The moisture that is not completely removed from the amorphous refractory forming the holding chamber container reacts with the molten metal and is taken into the molten metal in the form of hydrogen atoms, and is released into the molten metal as hydrogen gas bubbles. The moisture that is not completely removed from the insulating material located outside the holding chamber container reacts with the molten metal through the amorphous refractory forming the holding chamber container and is taken into the molten metal in the form of hydrogen atoms, and is released into the molten metal as hydrogen gas bubbles. These hydrogen gas bubbles may cause pinholes in the cast product. At present, hydrogen gas bubbles are removed by a degassing device using an inert gas (nitrogen, argon, etc.), but this is not sufficient, and there is a demand for further suppression of the release of hydrogen gas bubbles.

[0012] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a molten metal holding furnace that can efficiently heat molten metal while suppressing the generation of oxides and the release of hydrogen gas bubbles. [Means for solving the problem]

[0013] The aspects of the means for solving the above problems are as follows.

[0014] (First aspect) a holding chamber for holding the molten metal; a holding chamber cover that closes an upper opening of the holding chamber; a slender molten metal heating body extending obliquely downward from a side wall portion of the holding chamber and heating the molten metal inside the holding chamber; a bottom surface of the holding chamber located below the molten metal heating body has an inclined floor surface that is inclined in the same direction as the molten metal heating body while being spaced apart from the molten metal heating body by a predetermined distance; A space that is easily heated is formed between the molten metal heater and the inclined bed surface, The molten metal in the easily-heating space is in contact with a surface of the molten metal heater, so that heat from the molten metal heater is transferred to the molten metal. A molten metal holding furnace characterized by:

[0015] (Action and effect) According to the first aspect of the molten metal holding furnace, in the easily-heatable space formed between the molten metal heating body and the inclined floor surface of the holding chamber, the efficiency of thermal conduction from the entire molten metal heating body to the molten metal can be increased, and the molten metal in the holding chamber can be efficiently heated.

[0016] In addition, in the conventional holding chambers of a substantially cubic or rectangular parallelepiped shape in which the molten metal heater is placed vertically, the height of the holding chamber must be increased to a certain extent in order to accommodate the molten metal heater in the holding chamber. However, when the height of the holding chamber is increased, when the molten metal holding furnace and the existing equipment (for example, the molten metal supply equipment of a die casting machine, which has a maximum height of about 1200 mm; the same applies below) are installed side by side, the height of the molten metal holding furnace is often higher than that of the existing equipment. When a difference in height occurs between the molten metal holding furnace and the existing equipment, the labor required to move the molten metal from the molten metal holding furnace to the existing equipment is large, and the operating efficiency is poor. In addition, when the conventional molten metal heating body is placed vertically, if there is a space in which air exists between the ceiling and the molten metal, there is a risk that oxides are likely to adhere and form. Furthermore, since the entire molten metal heating body may not be immersed in the molten metal, it is not necessarily possible to efficiently heat the molten metal. In addition, even when the conventional molten metal heating body is placed vertically and the entire part to be heated is immersed in the molten metal, it is not necessarily possible to efficiently heat the molten metal. For example, consider a case where a molten metal heater is immersed in the molten metal in a melting chamber of a specific size, such as an approximately cube or rectangular parallelepiped, and the molten metal is heated by the molten metal heater with a specific output. In this case, the efficiency of heating the molten metal varies depending on how widely the molten metal heater comes into contact with the molten metal. In other words, the greater the surface area of ​​the molten metal heater that comes into contact with the molten metal, the more efficiently the molten metal can be heated. Therefore, even when a conventional molten metal heater is placed vertically and the entire part to be heated is immersed in the molten metal, it cannot necessarily be said that the molten metal is heated efficiently.

[0017] In order to prevent such problems from occurring, it is conceivable to reduce the height of the holding chamber and widen its width to make it have a similar capacity to the previous holding chamber, and to vertically place a short, wide-diameter molten metal heater in the holding chamber (the diameter needs to be made wider to achieve the same heating capacity as the previous molten metal heater). However, such a molten metal heater is a custom-made product, and is therefore significantly more expensive than the previous molten metal heater (about 10 times the price), resulting in a problem of high initial costs.

[0018] On the other hand, in the conventional holding chamber in which the molten metal heater is placed horizontally, the width of the holding chamber must be increased, which inevitably increases the bottom area of ​​the holding chamber and the installation area of ​​the holding chamber. In addition, if the molten metal heater is damaged, the molten metal may enter the molten metal heater from the damaged part, for example, up to the burner unit if the molten metal heater is an immersion burner, or up to the heater box if the molten metal heater is an immersion heater. In addition, if the molten metal heater is damaged, there is a problem in terms of work that the molten metal heater must be replaced after the molten metal heater is drained to a height lower than the height of the molten metal heater.

[0019] In order to solve the above problems, in the first embodiment, the molten metal heater extends obliquely downward from the side wall of the holding chamber. With this structure, the height of the holding chamber can be made lower than that of a conventional holding chamber in which the molten metal heater is placed vertically. As a result, the above-mentioned problem of reduced operating efficiency can be prevented. In addition, the entire molten metal heater can be immersed in the molten metal, and the length can be increased compared to conventional molten metal heaters placed vertically or horizontally because the molten metal heater extends obliquely downward, so the surface area of ​​the molten metal heater in contact with the molten metal is increased, and the molten metal is heated efficiently. Furthermore, the formation of oxide adhesion can be prevented. In addition, the bottom area of ​​the holding chamber can be made smaller than that of conventional holding chambers in which the molten metal heater is placed horizontally, so the installation area of ​​the holding chamber can be reduced, and even if the molten metal heater is damaged, there is no risk of the molten metal heater infiltrating the molten metal heater from the damaged area, for example, to the burner unit if the molten metal heater is an immersion burner, or to the heater box if the molten metal heater is an immersion heater. Furthermore, even if damage occurs, the molten metal heater can be replaced without draining the molten metal to a height lower than the placement height of the molten metal heater. Also, since the holding chamber can be made smaller, as described above, moisture from the unshaped refractory material forming the holding chamber container and the insulating material located on the outside of the holding chamber container reacts with the molten metal and is taken into the molten metal in the form of hydrogen atoms, and the amount of hydrogen gas released into the molten metal as bubbles is reduced, which inevitably suppresses the release of hydrogen gas bubbles.

[0020] In addition, in the first embodiment, an inclined floor surface is provided that is inclined in the same direction as the molten metal heater while leaving a predetermined gap between the molten metal heater and the inclined floor surface. By providing an inclined floor surface in the holding chamber in this manner, the distance between the molten metal heater and the inclined floor surface is kept constant, and the thermal conduction efficiency of the molten metal present in this gap is increased.

[0021] (Second aspect) a receiving chamber to which molten metal is supplied; a holding chamber communicating with the receiving chamber and holding the molten metal flowing in from the receiving chamber; a tapping chamber communicating with the holding chamber and configured to tap the molten metal flowing from the holding chamber; a holding chamber cover that closes an upper opening of the holding chamber without creating a space between the holding chamber and a liquid surface of the molten metal inside the holding chamber; a liquid level sensor for detecting when the liquid level of the molten metal in the tapping chamber has fallen to a lower limit level set at a height equal to or higher than the highest point of the lower surface of the holding chamber cover, a molten metal holding furnace that supplies the molten metal to the receiving chamber when it is detected that the level of the molten metal inside the tapping chamber has dropped to the lower limit level, and constantly maintains the level of the molten metal inside the tapping chamber at a height equal to or higher than the highest point on the underside of the holding chamber cover, a slender molten metal heater extending obliquely downward from a side wall of the holding chamber and heating the molten metal inside the holding chamber; a bottom surface of the holding chamber located below the molten metal heating body has an inclined floor surface that is inclined in the same direction as the molten metal heating body while being spaced apart from the molten metal heating body by a predetermined distance; A space that is easily heated is formed between the molten metal heater and the inclined bed surface, The molten metal in the easily-heating space is in contact with a surface of the molten metal heater, so that heat from the molten metal heater is transferred to the molten metal, a position of a connection portion between the side wall portion of the holding chamber and the molten metal heating body is lower than the lower limit level; A molten metal holding furnace characterized by:

[0022] (Action and effect) It is possible to achieve the same effects as those of the first aspect. Furthermore, in addition to the effects of the first aspect, it is possible to achieve the following effects.

[0023] That is, the above-mentioned Patent Document 1 refers to the possibility of oxides being generated near the submerged burner, and provides an inclusion floatation separator and a ceramic filter to remove inclusions such as oxides and foreign matter. The provision of this inclusion floatation separator and ceramic filter increases the initial cost and running cost, and also complicates the structure of the melting and holding furnace.

[0024] Furthermore, Patent Document 2 discloses a melting and holding furnace having a structure that prevents contact between the molten metal and air in order to suppress oxidation of the molten metal. Specifically, the structure disclosed does not create a space between the melting chamber cover at the top of the melting and holding furnace and the liquid surface of the molten metal.

[0025] However, the molten metal heating body (immersion burner or immersion heater) in Patent Document 2 is arranged so that it penetrates the melting chamber lid from above, or is arranged as a horizontal immersion type so that it penetrates the outer side wall of the melting chamber near the bottom of the melting chamber.

[0026] In the case of an arrangement in which the melting chamber lid is penetrated from above, it cannot be said that the molten metal is heated efficiently. For example, consider a case in which a 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 an approximately cube or approximately rectangular parallelepiped, and the molten metal is heated by the molten metal heating mechanism (immersion burner or immersion heater) with 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) comes into contact with the molten metal. In other words, the larger the surface area of ​​the molten metal heating mechanism (immersion burner or immersion heater) that comes into contact with the molten metal, the more efficiently the molten metal is heated. Therefore, in the case of an arrangement in which the melting chamber lid is penetrated from above, it cannot be said that the molten metal is heated efficiently. In addition, in the case of a horizontal immersion type arrangement penetrating from the outer side wall of the melting chamber near the bottom of the melting chamber, if the ceramic tube covering the immersion burner or immersion heater breaks, the molten metal may penetrate through the immersion burner or immersion heater to the respective burner units or heater box. In addition, in the case of a horizontal immersion type arrangement penetrating from the outer side wall of the melting chamber near the bottom of the melting chamber, if the above-mentioned damage occurs, there is a problem in terms of work in that the molten metal must be drained to a height lower than the height of the molten metal heating mechanism (immersion burner or immersion heater) and then the molten metal heating mechanism (immersion burner or immersion heater) must be replaced.

[0027] Therefore, in the second aspect, a structure is provided in which there is no space between the liquid surface of the molten metal in the holding chamber and the holding chamber lid, and this state can be maintained at all times, thereby preventing the occurrence of oxides due to air getting between the molten metal and the holding chamber lid.

[0028] At the same time, since the position of the connection portion between the side wall portion of the holding chamber and the molten metal heating body is set lower than the lower limit level, the connection portion between the side wall portion of the holding chamber and the molten metal heating body can be kept immersed in the molten metal at all times.

[0029] In the second embodiment, the molten metal heater is installed at an angle, and the connection part with the side wall of the holding chamber is at the highest position. The fact that the connection part at the highest position is always immersed in the molten metal means that the entire molten metal heater is always immersed in the molten metal.

[0030] As described above, according to the second aspect of the molten metal storage furnace, the molten metal heating body installed at an angle can be prevented from coming into contact with air, thereby preventing the formation of oxides around the molten metal heating body.

[0031] As a result, the possibility of oxides being mixed into the molten metal tapped from the molten metal holding furnace can be reduced, and high-quality molten metal can be provided to downstream equipment (for example, a die casting machine).

[0032] (Third aspect) The molten metal holding furnace of the first or second aspect, wherein the inclination angle of the molten metal heater and the inclination angle of the inclined floor surface are both within a range of 20 to 45 degrees.

[0033] (Action and effect) By making the molten metal heater and the inclined bed surface approximately parallel, the distance between the surface of the molten metal heater and the inclined bed surface becomes approximately the same at any point, so that heat can be uniformly transferred from the molten metal heater to the molten metal in the easy-to-heat space. As a result, the molten metal can be efficiently heated, and it is possible to prevent a situation in which a part of the molten metal is insufficiently heated and the quality of the molten metal is reduced.

[0034] In addition, by setting the inclination angle of the molten metal heater in the range of 20 to 45 degrees, the height of the molten metal holding furnace can be reduced. If the height of the molten metal holding furnace can be reduced, the difference in height between the molten metal holding furnace and other existing equipment is reduced. As a result, the effort required to move the molten metal from the molten metal holding furnace to the existing equipment is reduced, improving operating efficiency.

[0035] (Fourth aspect) The lower surface of the portion of the holding chamber cover located above the molten metal heater is Note The molten metal holding furnace of the first or second embodiment is inclined in the same direction as the molten metal heating body while leaving a predetermined gap between the molten metal heating body and the molten metal holding furnace.

[0036] (Action and effect) According to the fourth aspect of the molten metal holding furnace, the efficiency of heat transfer from the molten metal heating body to the molten metal in the gap between the molten metal heating body and the holding chamber lid can be increased, and the molten metal in the holding chamber can be efficiently heated.

[0037] (Fifth aspect) a holding chamber for holding the molten metal; a holding chamber cover that closes an upper opening of the holding chamber; a slender molten metal heating body extending obliquely downward from a side wall portion of the holding chamber and heating the molten metal inside the holding chamber; The lower surface of the portion of the holding chamber cover located above the molten metal heater is Note The molten metal heater is inclined in the same direction as the molten metal heater while leaving a predetermined gap between the molten metal heater and the molten metal heater. A molten metal holding furnace characterized by:

[0038] (Action and effect) The same effects as those of the first embodiment can be achieved.

[0039] (Sixth aspect) a receiving chamber to which molten metal is supplied; a holding chamber communicating with the receiving chamber and holding the molten metal flowing in from the receiving chamber; a tapping chamber communicating with the holding chamber and configured to tap the molten metal flowing from the holding chamber; a holding chamber cover that closes an upper opening of the holding chamber without creating a space between the holding chamber and a liquid surface of the molten metal inside the holding chamber; a liquid level sensor for detecting when the liquid level of the molten metal in the tapping chamber has fallen to a lower limit level set at a height equal to or higher than the highest point of the lower surface of the holding chamber cover, When it is detected that the level of the molten metal in the tapping chamber has fallen to the lower limit level, the molten metal is supplied to the receiving chamber, and the level of the molten metal in the tapping chamber is always maintained by the holding chamber cover. The highest point on the bottom surface This is a molten metal holding furnace that maintains the temperature at or above this level. a slender molten metal heater extending obliquely downward from a side wall of the holding chamber and heating the molten metal inside the holding chamber; The lower surface of the portion of the holding chamber cover located above the molten metal heater is Note The molten metal heater is inclined in the same direction as the molten metal heater while being spaced apart from the molten metal heater by a predetermined distance. a position of a connection portion between the side wall portion of the holding chamber and the molten metal heating body is lower than the lower limit level; A molten metal holding furnace characterized by:

[0040] (Action and effect) The same effects as those of the second and fourth aspects can be achieved.

[0041] (Seventh aspect) The molten metal holding furnace of the fifth or sixth aspect, wherein the inclination angle of the lower surface of the portion of the holding chamber cover located above the molten metal heater and the inclination angle of the molten metal heater are both within the range of 20 to 45 degrees.

[0042] (Action and effect) By arranging the bottom surface of the portion of the holding chamber lid located above the molten metal heater approximately parallel to the molten metal heater, the distance between the bottom surface of the portion of the holding chamber lid located above the molten metal heater and the molten metal heater is approximately the same at every point, so that heat can be uniformly transferred from the molten metal heater to the molten metal in the easy-to-heat space. As a result, the molten metal can be efficiently heated, and it is possible to prevent a situation in which a portion of the molten metal is insufficiently heated, causing a decrease in the quality of the molten metal.

[0043] In addition, by setting the inclination angle of the molten metal heater in the range of 20 to 45 degrees, the height of the molten metal holding furnace can be reduced. If the height of the molten metal holding furnace can be reduced, the difference in height between the molten metal holding furnace and other existing equipment is reduced. As a result, the effort required to move the molten metal from the molten metal holding furnace to the existing equipment is reduced, improving operating efficiency.

[0044] (Eighth aspect) The above Base end of molten metal heater The lower end of the molten metal heater base end but, The above The molten metal holding furnace according to any one of the first, second, fifth, and sixth aspects, wherein the molten metal holding furnace is at a position at least higher than the highest point of the underside of the holding chamber cover.

[0045] (Action and effect) Even if the molten metal heater is damaged and the molten metal enters the heater, the molten metal Base end of molten metal heater It never goes beyond the bottom.

[0046] (Ninth aspect) The molten metal holding furnace according to any one of the first, second, fifth and sixth aspects, wherein at least a portion of the lower surface of the holding chamber cover is recessed upward.

[0047] (Action and effect) At least a portion of the lower surface of the holding chamber lid is upwardly Sunken By forming a shape, Sunken The space created by the shape allows a larger amount of molten metal to be held. Effect of the Invention

[0048] According to the present invention, it is possible to provide a molten metal holding furnace that can efficiently heat molten metal while suppressing the generation of oxides and the release of hydrogen gas bubbles. [Brief description of the drawings]

[0049] [Figure 1] 1 is a schematic plan view showing a molten metal storage furnace 1 according to a first embodiment. [Diagram 2] 2 is a cross-sectional view of the holding chamber 13 taken along line XX in FIG. 1. [Diagram 3] FIG. 2 is a schematic plan view showing a molten metal storage furnace 1 according to a second embodiment. [Figure 4] 4 is a cross-sectional view taken along line YY in FIG. 3. [Diagram 5] 2 is a cross-sectional view taken along line XX of a holding chamber 13 according to another embodiment (third embodiment) of FIG. [Figure 6] FIG. 4 is a cross-sectional view showing a holding chamber 13 according to a comparative example. [Figure 7] 4 is a cross-sectional view taken along line YY in FIG. 3, in which the lower surface of the holding chamber cover is recessed upward. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] A preferred embodiment of a molten metal storage furnace 1 according to the present invention will be described below with reference to the drawings. Note that the following description and the drawings merely show one example of an embodiment of the present invention, and the contents of the present invention should not be interpreted as being limited to this embodiment.

[0051] First embodiment A first embodiment of a molten metal storage furnace 1 according to the present invention is shown in Figs. 1 and 2. This molten metal storage furnace 1 has a receiving chamber 11 for receiving molten metal MM such as an aluminum alloy, a holding chamber 13 for holding the molten metal, and a discharging chamber 16 for discharging the molten metal MM. A molten metal heater 2 is provided in the holding chamber 13. 3 A holding chamber cover 13C is provided to close the upper opening of the holding chamber.

[0052] (Holding chamber 13) The holding chamber 13 is the space inside a holding chamber container 13D, and the molten metal MM is held in this holding chamber 13. In order to prevent a decrease in the temperature of the molten metal MM in the holding chamber 13, a molten metal heater 2 is provided.

[0053] The molten metal heater 2 is not particularly limited, but it is preferable that it does not impede the movement of the molten metal MM, and an elongated heater is preferable rather than a plate-shaped heater. Specifically, it is preferable to use a tube-shaped heater such as a tube burner or a tube heater. There is no particular limit to the number of molten metal heaters 2 as long as the temperature of the molten metal MM can be appropriately maintained. In the first embodiment shown in FIG. 1, three molten metal heaters 2 are installed in the holding chamber 13.

[0054] The base end of the molten metal heating body 2 is provided on the side wall portion of the holding chamber 13. In the example of FIG. 2, the base end of the molten metal heating body 2 is attached to the upper part of the side wall 13Ds (side wall on the left side of the drawing) of the holding chamber container 13D and the upper part of the side wall (side wall on the left side of the drawing) of the heat insulating material 13E located outside the holding chamber container 13D by penetrating the holding chamber container 13D and the heat insulating material 13E. The molten metal heating body 2 extends from the side wall portion of the holding chamber 13 obliquely downward of the holding chamber 13. In the example of FIG. 2, the molten metal heating body 2 is provided so as to extend from the upper part of the side wall 13Ds (side wall on the left side of the drawing) of the holding chamber container 13D toward the opposite floor 13Db (floor on the right side of the drawing). That is, the molten metal heater 2 extends from an upper portion of a side wall 13Ds (the side wall on the left side in the drawing) of the holding chamber vessel 13D toward a lower portion of the opposite side wall 13Ds (the side wall on the right side in the drawing).

[0055] The inclination angle of the molten metal heater 2 can be determined arbitrarily, but the depression angle α between the axis 2x of the molten metal heater 2 and the imaginary horizontal line 2y is preferably set to 20 to 45 degrees, and more preferably 30 to 40 degrees.

[0056] When the angle α is less than 20 degrees, it is possible to reduce the height of the holding chamber 13. As a result, there is an advantage that it is possible to prevent the inconvenience of a decrease in the operating efficiency of existing equipment, etc., as described above.

[0057] However, if the height of the holding chamber 13 is made too low, it becomes necessary to change the heights of the receiving chamber 11 and the tapping chamber 16. In other words, if the heights of the receiving chamber 11 and the tapping chamber 16 are not changed, the heights of the chambers 11, 13, and 16 will differ greatly, causing the shape of each transport path (first transport path W1 and second transport path W2) of the receiving chamber 11 and the tapping chamber 16 connected to the holding chamber 13 to become distorted, making it difficult for the molten metal MM to flow between the chambers 11, 13, and 16.

[0058] Moreover, there is no need to make the angle α of the molten metal heater 2 too small.

[0059] In addition, as the angle α of the molten metal heating body 2 becomes smaller, the extension direction of the molten metal heating body 2 becomes closer to horizontal, so it becomes necessary to increase the width of the holding chamber 13 in order to accommodate the molten metal heating body 2. As a result, there arises an inconvenience that a large space is required to install the holding chamber 13.

[0060] Furthermore, as the width of the holding chamber 13 increases, the area of ​​the bottom surface of the holding chamber 13 also tends to increase. If the area of ​​the bottom surface of the holding chamber 13 is large, there are disadvantages such as increased heat dissipation and a larger installation area.

[0061] From the above, it is preferable that the angle α of the molten metal heater 2 is set to 20 degrees or more.

[0062] On the other hand, if the angle α is greater than 45 degrees, the height of the holding chamber 13 that accommodates the molten metal heating body 2 cannot be reduced, which may result in the inconvenience of a decrease in the operating efficiency of existing equipment, etc., as described above.

[0063] In view of the above operational inconveniences, it is preferable to set the angle α to 45 degrees or less.

[0064] In the example of FIG. 2, the left and right side walls 13Ds of the holding chamber vessel 13D are almost vertical, and the floor 13Db on the right side of the drawing is almost horizontal. On the other hand, the floor 13Db on the left side of the drawing of the holding chamber vessel 13D is inclined downward from the left side to the right side of the drawing, similar to the molten metal heating body 2. It is preferable that the inclination angle β of the inclined floor surface 13Db1 of the floor 13Db of this holding chamber vessel 13D (the depression angle β between the extension line 13Dx of the inclined floor surface 13Db1 and the imaginary horizontal line 13Dy) is almost the same as the inclination angle α of the molten metal heating body 2. For example, when the inclination angle α of the molten metal heating body 2 is 35 degrees, the inclination angle β of the inclined floor surface 13Db1 is also preferably about 33 to 37 degrees, and most preferably 35 degrees. By adjusting the inclination angles α and β, the molten metal heating body 2 and the inclined bed surface 13Db1 can be made almost parallel, so that the distance X (the distance in the direction perpendicular to the axis 2x of the molten metal heating body 2) between the surface of the molten metal heating body 2 and the bed portion 13Db (inclined bed surface 13Db1) is almost the same at any point. As a result, heat can be uniformly transferred from the molten metal heating body 2 to the molten metal MM in the space Y between the molten metal heating body 2 and the inclined bed surface 13Db1, so that the molten metal MM can be heated uniformly.

[0065] That is, the molten metal MM tends to be more easily heated the closer it is to the molten metal heating body 2, which is the heat generation source, and in particular, the space Y between the surface of the molten metal heating body 2 and the inclined bed surface 13Db1 improves heating efficiency because the heat generated from the molten metal heating body 2 hits the inclined bed surface 13Db1 and is reflected back to the molten metal heating body 2. By making the distance X between the outer surface of the molten metal heating body 2 and the inclined bed surface 13Db1 approximately the same at any position in the axial direction of the molten metal heating body 2, the temperature in the space Y becomes approximately the same at any point, making it difficult for temperature unevenness to occur in the space Y.

[0066] In addition, the holding chamber 13 shown in FIG. 2 has a shorter distance X from the molten metal heater 2 to the floor 13Db below it, compared to the case in which the floor 13Db of the holding chamber 13 is not inclined as shown in FIG. 6. As a result, the embodiment shown in FIG. 2 can heat the molten metal MM in the space Y more easily than the embodiment shown in FIG. 6. Furthermore, since the holding chamber 13 shown in FIG. 2 can be made smaller than the holding chamber 13 shown in FIG. 6, as described above, moisture from the unshaped refractory material forming the holding chamber container 13D and the heat insulating material 13E located outside the holding chamber container 13D reacts with the molten metal MM and is taken into the molten metal MM in the form of hydrogen atoms, and the amount of hydrogen gas released into the molten metal MM as bubbles is also reduced, which inevitably suppresses the release of hydrogen gas bubbles.

[0067] 2, when an inclined floor surface 13Db1 is provided on the holding chamber vessel 13D, 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 space Y becomes too small, so that the amount of the molten metal MM in the space Y decreases, and as a result, there is a risk of the temperature unevenness becoming large in the holding chamber 13. On the other hand, if the distance X is longer than 13 cm, the space Y becomes too large, so that the amount of the molten metal MM in the space Y increases, resulting in undesirable phenomena such as a decrease in heating efficiency.

[0068] 6, the distance from the molten metal heater 2 to the floor 13Db below it varies widely. In such cases, the distance X refers to the average distance from the molten metal heater 2 to the floor 13Db below it.

[0069] 2, the floor portion 13Db of the holding chamber container 13D has a side extension surface 13Db2 that extends laterally from the lower end of the inclined floor surface 13Db1. This side extension surface 13Db2 extends laterally almost horizontally from the lower end of the inclined floor surface 13Db1.

[0070] If there is foreign matter (hereinafter, referred to as "unwanted matter") in the molten metal MM inside the holding chamber 13, this foreign matter will gradually accumulate on the floor 13Db of the holding chamber 13 due to gravity over time.

[0071] As shown in FIG. 2, by providing an inclined floor surface 13Db1 on the floor portion 13Db of the holding chamber 13, the unwanted objects that fall onto the inclined floor surface 13Db1 roll down along the inclination of the inclined floor surface 13Db1 and accumulate on the side extension surface 13Db2. That is, the unwanted objects do not scatter over the entire bottom surface of the holding chamber 13, but rather naturally gather on the side extension surface 13Db2. Therefore, when the opening cover 13Ca provided on the holding chamber cover 13C is opened and a ladle or the like is inserted into the holding chamber 13 through the opening 13Ca1 to scoop up and collect the unwanted objects, the unwanted objects accumulated on the side extension surface 13Db2 can be scooped up. Therefore, compared to the case where the inclined floor surface 13Db1 is not provided as in FIG. 6, the unwanted objects are not scattered, and the collection efficiency of the unwanted objects can be improved.

[0072] 1 and 2, it is preferable to provide a more recessed portion (groove portion 13Db3) on side extending surface 13Db2. By providing such groove portion 13Db3, when collecting unwanted objects, the unwanted objects on side extending surface 13Db2 can be dropped into groove portion 13Db3, and then a ladle can be inserted into groove portion 13Db3 and moved along the extension direction of groove portion 13Db3, making it easier to collect the unwanted objects.

[0073] The opening 13Ca1 of the holding chamber cover 13C has an inner peripheral surface that is inclined such that the opening area is gradually wider toward the top. The opening cover 13Ca has an outer peripheral surface that is inclined corresponding to the inner peripheral surface of the opening 13Ca1 so that it can be fitted into the opening 13Ca1 from above. Therefore, compared to a case having vertical inner and outer peripheral surfaces, it is difficult to create a gap when fitting, and oxidation is prevented, and the opening 13Ca1 can be easily closed by simply fitting the opening cover 13Ca into the opening 13Ca1 from above. In addition, when the opening cover 13Ca is lifted and removed for maintenance, the opening cover 13Ca can be prevented from falling to the bottom of the holding chamber 13. Note that, by fitting the opening cover 13Ca into the opening 13Ca1, the opening cover 13Ca functions as a part of the holding chamber cover 13C, so the opening cover 13Ca can also be said to be a part of the holding chamber cover 13C.

[0074] The space Y between the molten metal heater 2 and the inclined bed surface 13Db1 is also called an easily heated space, since it is a space in which the molten metal MM can be easily heated. Since the amount of the molten metal MM present in this easily heated space is not large, the heat of the molten metal heater 2 is transferred to the molten metal MM by contacting the surface of the molten metal heater 2, and the molten metal MM is easily heated.

[0075] Second Embodiment A second embodiment of a molten metal storage furnace 1 according to the present invention is shown in FIGS.

[0076] The molten metal holding furnace 1 has a receiving chamber 11 for receiving molten metal MM such as an aluminum alloy, a holding chamber 13 for holding the molten metal MM, and a tapping chamber 16 from which the molten metal MM is tapped. In the following explanation, descriptions of the same parts as in the first embodiment, such as the structure of the holding chamber 13 and the method of installing the molten metal heater 2, will be omitted.

[0077] A holding chamber cover 13C is provided above the holding chamber 13, closing the upper opening of the holding chamber 13 without creating any space between the holding chamber 13 and the liquid surface of the molten metal MM inside the holding chamber 13.

[0078] As shown in FIG. 4, the discharge chamber 16 is provided with a lower limit level sensor 17A that detects that the level of the molten metal MM in the discharge chamber 16 has fallen to a lower limit level L2 set at a height equal to or higher than the highest position HL of the lower surface of the holding chamber cover 13C of the holding chamber 13. This lower limit level sensor 17A detects that the level of the molten metal MM in the discharge chamber 16 is approaching (or / and has reached) the lower limit level L2. Then, information indicating that the level of the molten metal MM in the discharge chamber 16 is approaching (or / and has reached) the lower limit level L2 is transmitted to the control unit 20. The control unit 20 that has received this information determines whether or not to supply new molten metal MM to the receiving chamber 11, and if so, how much molten metal MM to supply. If it is determined that the molten metal MM should be supplied, it issues a command to the molten metal supply unit 21, and the molten metal supply unit 21 supplies the molten metal MM in the commanded amount to the receiving chamber 11. As the molten metal supply section 21, for example, a known transport mechanism for pouring the molten metal MM from a melting furnace located at a distant location into the receiving chamber 11 using a trough can be used.

[0079] By supplying the molten metal MM to the receiving chamber 11, a portion of the molten metal MM in the receiving chamber 11 flows through the first transfer passage W1 to the holding chamber 13, and a portion of the molten metal MM in the holding chamber 13 flows through the second transfer passage W2 to the tapping chamber 16. As a result, the liquid level in the tapping chamber 16 rises.

[0080] Similarly, by taking out (pouring) the molten metal MM from the tapping chamber 16, a portion of the molten metal MM in the receiving chamber 11 flows through the first transfer path W1 to the holding chamber 13, and a portion of the molten metal MM in the holding chamber 13 flows through the second transfer path W2 to the tapping chamber 16. As a result, the liquid level in the receiving chamber 11 drops.

[0081] As described above, by supplying the molten metal MM to the receiving chamber 11 and removing the molten metal MM 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.

[0082] Furthermore, since the receiving chamber 11, the holding chamber 13 and the outlet chamber 16 are connected to each other via the first transport path W1 and the second transport path W2, the liquid levels in the receiving chamber 11, the holding chamber 13 and the outlet chamber 16 are basically always at the same height.

[0083] With the above-described mechanism, the height of the liquid level in the tapping chamber 16 can be maintained at a height position equal to or higher than the highest position HL of the underside of the holding chamber lid 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 lid 13C, which makes it possible to prevent contact between the molten metal MM and air in the holding chamber 13. Contact between the molten metal MM and air can cause metal oxides to be generated, but the configuration of this embodiment makes it possible to prevent the generation of metal oxides.

[0084] 2, inside the holding chamber 13, the entire molten metal heater 2 is always immersed in the molten metal MM. That is, inside the holding chamber 13, the inner surface of the side wall 13Ds of the holding chamber container 13D and the grounded portion 13F of the molten metal heater 2 (more specifically, the upper end of the grounded portion 13F (referred to as the "upper end grounded portion 13Ft")) are the highest parts of the molten metal heater 2. Since the height of the upper end grounded portion 13Ft is equal to or lower than the lower limit level L2, the upper end grounded portion 13Ft is always immersed in the molten metal MM in the holding chamber 13. Furthermore, inside the holding chamber 13, other parts of the molten metal heater 2 other than the upper end grounded portion 13Ft are located lower than the upper end grounded portion 13Ft, so the other parts are also always immersed in the molten metal MM in the holding chamber 13.

[0085] Therefore, the molten metal heater 2, which is installed in a diagonally downward position, can be prevented from coming into contact with air, thereby preventing the generation of oxides around the molten metal heater 2. As a result, the possibility of oxides being mixed into the molten metal MM tapped from the molten metal storage furnace 1 can be reduced, and high-quality molten metal MM can be provided to downstream equipment (e.g., a die-casting machine).

[0086] Furthermore, if the molten metal heating body 2 is exposed to air inside the holding chamber 13, the molten metal heating body 2 will also heat the air, which may reduce the heating efficiency of the molten metal heating body 2. However, in the second embodiment (and the first embodiment), the entire molten metal heating body 2 is always immersed in the molten metal MM inside 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 heated efficiently.

[0087] As shown in Figs. 3 and 4, it is preferable to provide a molten metal heating body 2 such as a heater inside the tapping chamber 16 in order to prevent the temperature of the molten metal MM in the tapping chamber 16 from decreasing. In this case, the shape of the molten metal heating body 2 and the bottom surface of the tapping chamber 16 can be the same as the molten metal heating body 2 in the holding chamber 13 and the holding chamber container 13D. That is, when the heating efficiency of the molten metal heating body 2 in the tapping chamber 16 is important, it is preferable to arrange the molten metal heating body 2 so that it extends diagonally downward from the side wall of the tapping chamber 16 in the tapping chamber 16 as in the shape shown in Fig. 2, and to make the bottom surface of the tapping chamber 16 located below the molten metal heating body 2 an inclined floor surface inclined in the same direction as the molten metal heating body 2 so as to be approximately parallel to the molten metal heating body 2. In this case, an easily heated space is formed between the inclined floor surface of the tapping chamber 16 and the molten metal heating body 2, and the molten metal MM in the easily heated space comes into contact with the surface of the molten metal heating body 2, so that the heat of the molten metal heating body 2 is transferred to the molten metal MM.

[0088] An upper limit level sensor 17B may be further provided in the tap water discharge chamber 16. As shown in Fig. 4, in addition to the lower limit level sensor 17A that detects the lower limit level L2 set at a height equal to or higher than the highest position HL of the underside of the holding chamber lid 13C, an upper limit level sensor 17B that detects the upper limit level L1 set at a position higher than the lower limit level L2 is provided. The lower limit level sensor 17A may be at the same height as the highest position HL of the lower surface of the holding chamber lid 13C, but is preferably at a higher height than this. The liquid level sensor 17 may be a liquid level sensor 17 that integrates the upper limit level sensor 17B and the lower limit level sensor 17A.

[0089] When the lower limit level sensor 17A detects the molten metal level, it transmits this information to the control unit 20. The control unit 20, having received this information, determines whether or not to supply new molten metal MM to the receiving chamber 11, and if so, how much molten metal MM to supply. When it is determined that molten metal MM should be supplied, a command is issued to the molten metal supply unit 21, which supplies the commanded amount of molten metal MM to the receiving chamber 11. As a result, the molten metal level position in the tapping chamber 16 is maintained at a position always higher than the highest position HL of the underside of the holding chamber cover 13C, so that the molten metal MM does not come into contact with the air inside the holding chamber 13, and oxidation of the molten metal MM can be prevented.

[0090] Moreover, when the upper limit level sensor 17B detects the molten metal surface, it transmits the information to the control unit 20. The control unit 20, which has received the information, issues a command to the molten metal supply unit 21, which then stops the supply of the molten metal MM. retention Over-feeding of the furnace 1 can be prevented.

[0091] Third embodiment Fig. 5 shows a holding chamber 13 (third embodiment) different from the embodiment shown in Fig. 2. The holding chamber 13 shown in Fig. 5 can be used in the molten metal storage furnace 1 of the first and second embodiments, similar to the holding chamber 13 of the embodiment shown in Fig. 2.

[0092] The holding chamber 13 in Fig. 5 is almost the same as the holding chamber 13 in Fig. 2, so a description of the same parts will be omitted and only the different parts will be described. The holding chamber 13 in Fig. 5 is characterized in that the lower surface 13Cb of the holding chamber lid 13C that covers the holding chamber 13 is inclined. Specifically, the lower surface 13Cb of the holding chamber lid 13C located above the molten metal heating body 2 is inclined in the same direction as the molten metal heating body 2 while leaving a predetermined gap between them. This point will be described in detail below.

[0093] In the example of FIG. 5, a part of the lower surface 13Cb of the holding chamber cover 13C that covers the holding chamber 13 is inclined downward from the left side to the right side of the drawing, similar to the molten metal heater 2. Hereinafter, the lower surface 13Cb of the holding chamber cover 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 holding chamber cover 13C that is inclined in a different direction from the molten metal heater 2 is referred to as the different-direction inclined or horizontal lower surface 13Cb2. It is preferable that 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 virtual horizontal line 13Cy) is 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 also preferably about 33 to 37 degrees, and most preferably 35 degrees. By adjusting the inclination angles α and θ, the molten metal heater 2 and the same-direction inclined lower surface 13Cb1 of the holding chamber lid 13C can be made almost parallel to each other, so that the distance P (the distance in the direction perpendicular to the axis 2x of the molten metal heater 2) between the surface of the molten metal heater 2 and the same-direction inclined lower surface 13Cb1 of the holding chamber lid 13C becomes almost the same at any point. As a result, heat can be uniformly transferred from the molten metal heater 2 to the molten metal MM flowing in the space Q between the molten metal heater 2 and the same-direction inclined lower surface 13Cb1 of the holding chamber lid 13C, so that the temperature unevenness of the molten metal MM can be reduced and efficient heating is possible. In other words, the space Q between the surface of the molten metal heater 2 and the same-direction inclined lower surface 13Cb1 of the holding chamber lid 13C can have the same effect as the space Y described above. The effect of reducing the temperature unevenness of the molten metal MM and enabling efficient heating by providing this space Q can be easily explained. heating Since it is similar to space Y, a detailed description will be omitted here.

[0094] 5, in the case where 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 molten metal heater 2 to the lower surface 13Cb1 inclined in the same direction is preferably 7 to 13 cm, more preferably 10 to 11 cm. If the distance P is shorter than 7 cm, the space Q becomes too small, so that the amount of the molten metal MM flowing in the space Q per unit time decreases, and as a result, the temperature unevenness in the holding chamber 13 increases, and the heating efficiency may decrease. On the other hand, if the distance P is longer than 13 cm, the speed of the molten metal MM flowing in the space Q does not increase, so that the amount of the molten metal MM contacting the surface of the molten metal heater 2 on the space Q side decreases, and therefore the heat from the molten metal heater 2 is not easily transferred to the molten metal MM, which may decrease the heating efficiency of the molten metal MM and increase the temperature unevenness.

[0095] A lower limit level sensor 17A is provided inside the discharge chamber, which keeps the molten metal level in the discharge chamber 16 always above the highest point HL on the underside of the holding chamber lid 13C. This prevents the molten metal MM from coming into contact with the air inside the holding chamber 13, thereby preventing oxidation of the molten metal MM. The highest point HL on the underside of the holding chamber lid 13C shown in Figures 2 and 5 represents the upper limit position of the molten metal MM within the holding chamber 13, and is below the lower limit level L2 of the tapping chamber 16, and preferably below this.

[0096] The base end 14F of the molten metal heating body 2 (more specifically, the lower end of the base end 14F of the molten metal heating body (referred to as the "lower end 14Ft of the base end of the molten metal heating body") is at a position at least higher than the highest point HL of the underside of the holding chamber lid 13C. Preferably, it is at a position higher than the upper limit level L1. As a result, as in the second embodiment, the height of the liquid level in the discharge chamber 16 is maintained at a height position equal to or higher than the highest point HL of the underside of the holding chamber lid 13C, and there is always no space between the liquid level of the molten metal MM in the holding chamber 13 and the holding chamber lid 13C. Therefore, even if the molten metal heating body 2 is damaged in this state and the molten metal MM invades the molten metal heating body 2, the invaded molten metal MM will not exceed the lower end 14Ft of the base end of the molten metal heating body.

[0097] As shown in FIG. 7, at least a part of the lower surface of the holding chamber cover 13C may be recessed upward. The central part of the lower surface of the holding chamber cover 13C, excluding the peripheral part, may be recessed upward. In addition, as in the fifth and sixth embodiments, when the lower surface of the part of the holding chamber cover 13C located above the molten metal heating body 2 is inclined in the same direction as the molten metal heating body 2 while leaving a predetermined gap from the molten metal heating body 2, at least a part of the lower surface of the holding chamber cover 13C other than the part of the lower surface located above the molten metal heating body 2 and inclined in the same direction as the molten metal heating body 2 while leaving a predetermined gap from the molten metal heating body 2 can be recessed upward. This makes it possible to hold a larger amount of molten metal by the amount of the space of the recessed shape. However, the recessed ceiling surface is lower than the upper edge of at least one of the upper edges of the receiving chamber 11 and the tapping chamber 16, which has a lower height. If the ceiling surface is high, there is a risk that the molten metal MM will flow out from the upper edge of at least one of the receiving chamber 11 and the discharging chamber 16, whichever is lower in height than the ceiling surface.

[0098] (Comparative Example) A holding chamber 13 according to a comparative example is shown in Fig. 6. This comparative example in Fig. 6 is shown to explain the effect of the configurations in Fig. 2 and Fig. 5 in comparison with the embodiments in Fig. 2 and Fig. 5, and does not represent a conventionally known holding chamber 13. [Industrial Applicability]

[0099] The molten metal may be aluminum or an aluminum alloy, or may be other molten metal MM.

[0100] 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 spirit of the present invention. For example, the molten metal holding furnace 1 of the present invention can be used in melting and holding furnaces, melting furnaces, low-pressure casting furnaces, etc. [Explanation of symbols]

[0101] 1... Molten metal holding furnace, 2... Molten metal heating element, 2x... Axis of the molten metal heating element, 2y... Virtual horizontal line (of the molten metal heating element), 11... Molten metal receiving chamber, 11D... Molten metal receiving chamber container, 13... Holding chamber, 13C... Holding chamber lid, 13Ca... Opening Lid, 13Ca1...opening, 13Cb...lower surface of holding chamber lid, 13Cb1...lower surface inclined in the same direction, 13Cb2...lower surface inclined in a different direction or horizontally, 13Cx...extension line of lower surface inclined in the same direction, 13Cy...(inclined in the same direction) 13D...Holding chamber vessel, 13Db...Floor (of metal melting chamber vessel), 13Db1...Inclined floor surface, 13Db2...Side extension surface, 13Db3...Groove portion, 13Dx...Extension line of inclined floor surface, 13Ds...Side wall (of metal melting chamber vessel), 13Dy...Imaginary horizontal line (of inclined floor surface), 13E...Insulation material, 13F...Ground portion, 13Ft...Upper end ground portion, 14F...Base end of molten metal heater, 14Ft...Base of molten metal heater Lower end of end portion, 16... discharging chamber, 16D... discharging chamber container, 17... liquid level sensor, 17A... lower limit level sensor, 17B... upper limit level sensor, 20... control portion, 21... molten metal supply portion, 22... downstream device (die casting machine, etc.), HL... highest position on the underside of the holding chamber lid, L1... upper limit level, L2... lower limit level, ML... liquid level, MM... molten metal, P... same direction of upper surface of molten metal heater and holding chamber lid Distance between the inclined lower surface, Q...Easily heated space (upper easily heated space), W1...First conveying path, W2...Second conveying path, X...Distance between the lower surface of the molten metal heating body and the inclined floor surface, Y...Easily heated space (lower easily heated space), α...Inclination angle of the molten metal heating body, β...Inclination angle of the inclined floor surface, θ...Inclination angle of the inclined lower surface in the same direction, HD...Height direction, DS...Lower side (lower), US...Upper side (upper), WD...Width direction, LS...Left side, RS...Right side

Claims

1. a holding chamber for holding the molten metal; a holding chamber cover that closes an upper opening of the holding chamber; a slender molten metal heating body extending obliquely downward from a side wall portion of the holding chamber and heating the molten metal inside the holding chamber; a bottom surface of the holding chamber located below the molten metal heating body has an inclined floor surface that is inclined in the same direction as the molten metal heating body while being spaced apart from the molten metal heating body by a predetermined distance; A space that is easily heated is formed between the molten metal heater and the inclined bed surface, The molten metal in the easily-heating space is in contact with a surface of the molten metal heater, so that heat from the molten metal heater is transferred to the molten metal. A molten metal holding furnace characterized by:

2. a receiving chamber to which molten metal is supplied; a holding chamber communicating with the receiving chamber and holding the molten metal flowing in from the receiving chamber; a tapping chamber communicating with the holding chamber and configured to tap the molten metal flowing from the holding chamber; a holding chamber cover that closes an upper opening of the holding chamber without creating a space between the holding chamber and a liquid surface of the molten metal inside the holding chamber; a liquid level sensor for detecting when the liquid level of the molten metal in the tapping chamber has fallen to a lower limit level set at a height equal to or higher than the highest point of the lower surface of the holding chamber cover, a molten metal holding furnace that supplies the molten metal to the receiving chamber when it is detected that the level of the molten metal inside the tapping chamber has dropped to the lower limit level, and constantly maintains the level of the molten metal inside the tapping chamber at a height equal to or higher than the highest point on the underside of the holding chamber cover, a slender molten metal heater extending obliquely downward from a side wall of the holding chamber and heating the molten metal inside the holding chamber; a bottom surface of the holding chamber located below the molten metal heating body has an inclined floor surface that is inclined in the same direction as the molten metal heating body while being spaced apart from the molten metal heating body by a predetermined distance; A space that is easily heated is formed between the molten metal heater and the inclined bed surface, The molten metal in the easily-heating space is in contact with a surface of the molten metal heater, so that heat from the molten metal heater is transferred to the molten metal, a position of a connection portion between the side wall portion of the holding chamber and the molten metal heating body is lower than the lower limit level; A molten metal holding furnace characterized by:

3. 3. The molten metal holding furnace according to claim 1, wherein the inclination angle of said molten metal heater and the inclination angle of said inclined bed surface are both within a range of 20 to 45 degrees.

4. 3. A molten metal holding furnace according to claim 1, wherein the underside of the portion of the holding chamber cover located above the molten metal heater is inclined in the same direction as the molten metal heater while leaving a predetermined gap between the holding chamber cover and the pre-molten metal heater.

5. a holding chamber for holding the molten metal; a holding chamber cover that closes an upper opening of the holding chamber; a slender molten metal heating body extending obliquely downward from a side wall portion of the holding chamber and heating the molten metal inside the holding chamber; a lower surface of a portion of the holding chamber cover located above the molten metal heater is inclined in the same direction as the molten metal heater while leaving a predetermined gap between the lower surface and the previous molten metal heater; A molten metal holding furnace characterized by:

6. a receiving chamber to which molten metal is supplied; a holding chamber communicating with the receiving chamber and holding the molten metal flowing in from the receiving chamber; a tapping chamber communicating with the holding chamber and configured to tap the molten metal flowing from the holding chamber; a holding chamber cover that closes an upper opening of the holding chamber without creating a space between the holding chamber and a liquid surface of the molten metal inside the holding chamber; a liquid level sensor for detecting when the liquid level of the molten metal in the tapping chamber has fallen to a lower limit level set at a height equal to or higher than the highest point of the lower surface of the holding chamber cover, a molten metal holding furnace that supplies the molten metal to the receiving chamber when it is detected that the level of the molten metal inside the tapping chamber has dropped to the lower limit level, and constantly maintains the level of the molten metal inside the tapping chamber at a level equal to or higher than the lowermost surface of the holding chamber cover, a slender molten metal heater extending obliquely downward from a side wall of the holding chamber and heating the molten metal inside the holding chamber; a lower surface of a portion of the holding chamber cover located above the molten metal heating body is inclined in the same direction as the molten metal heating body while leaving a predetermined gap between the lower surface and the previous molten metal heating body; a position of a connection portion between the side wall portion of the holding chamber and the molten metal heating body is lower than the lower limit level; A molten metal holding furnace characterized by:

7. 7. The molten metal holding furnace according to claim 5, wherein the inclination angle of the lower surface of the portion of the holding chamber cover located above the molten metal heater and the inclination angle of the molten metal heater are both within the range of 20 to 45 degrees.

8. The lower end of the base end of the molten metal heating body is located higher than the highest point of the lower surface of the holding chamber cover. The molten metal holding furnace according to any one of claims 1 to 6.

9. 7. The molten metal holding furnace according to claim 1, wherein at least a portion of the lower surface of said holding chamber cover is recessed upward.

Images