JP5075231B2 - Molten aluminum feeder and its feeding method - Google Patents

Description

  The present invention relates to a molten aluminum supply device used for conveying molten aluminum and a method for supplying the molten aluminum, and in particular, the molten aluminum oxide adhering to the inner periphery of the duct when hot water is stopped peels off the molten aluminum in the duct. The present invention relates to a molten aluminum supply device and a molten aluminum supply method for preventing the flow of the liquid.

  For example, in the field of aluminum casting, in order to supply molten aluminum to a conveyance destination such as a mold, a container supply apparatus using an electromagnetic pump for molten aluminum that conveys the molten aluminum by applying an electromagnetic induction action is used. Such an electromagnetic pump for molten aluminum is an induction type electromagnetic pump of a type in which a moving magnetic field is generated inside a cylindrical duct by an inductor in which a coil is wound around a yoke made of a magnetic material, and thrust is applied to the molten aluminum to supply it. Is the mainstream.

  An induction type electromagnetic pump used for such a container supply device is described in, for example, Patent Document 2 (Japanese Patent Laid-Open No. 2006-341281). The tubular duct through which the molten aluminum flows is composed of a duct made of cylindrical ceramics having heat resistance and corrosion resistance, and a moving magnetic field is generated on the outer periphery of the duct. Therefore, an inductor having a coil wound around a yoke is disposed, A magnetic core serving as a magnetic path of a magnetic field generated by an inductor is disposed inside a tubular duct. The core is covered with a protective tube made of cylindrical ceramics having heat resistance and corrosion resistance. Accordingly, the flow path of the molten aluminum becomes an annular portion formed between the tubular duct and the protective tube, and thus this type of electromagnetic pump is called an annular flow type electromagnetic pump.

  A molten aluminum supply device using such an electromagnetic pump for molten aluminum is used to intermittently supply a constant amount of molten aluminum to a transport destination such as a die casting device or a gravity casting device every time. When molten aluminum is supplied by driving the electromagnetic pump, the duct is heated by a heater, and the temperature inside the duct is maintained at a temperature equal to or higher than the melting point of the molten aluminum so that the molten aluminum passing through the duct does not solidify. On the other hand, when the drive of the electromagnetic pump is stopped and the supply of molten aluminum is stopped, the heating of the duct by the heater is also stopped.

  However, the drive of the electromagnetic pump is stopped, the supply of molten aluminum is stopped, the heating of the duct by the heater is stopped for a while, the duct is heated again by the heater after a while, the electromagnetic pump is driven, and the melting is performed. When the supply of aluminum is started, a thick film piece of molten aluminum oxide may be mixed in the duct. This molten aluminum oxide thick film piece hinders the flow of molten aluminum in the duct, or the oxide thick film piece is transported to the intended supply destination, causing problems such as deterioration in casting quality. . Therefore, when the supply of molten aluminum is started, it is necessary to remove the thick film piece of the molten aluminum oxide.

  The inventors of the present invention examined the cause of the generation of the thick film piece of the molten aluminum oxide, and found that it was in the following phenomenon. In order to supply molten aluminum, a molten aluminum film adheres to the inner surface of the duct after the molten aluminum is stopped through the molten aluminum while heating the duct with a heater. In the case where molten aluminum is supplied without lowering the duct temperature, the molten aluminum adhering to the inner surface of the duct is constantly washed by the molten aluminum passing through the duct and continuously updated in a metallic state. However, when the supply of molten aluminum is stopped and the heating of the duct is stopped, the surface of the molten aluminum attached to the inner surface of the duct comes into contact with air and oxidizes, and an oxide film is formed on the surface. When the duct temperature is 250 ° C. or less, this oxide film increases in strength of aluminum solidified between the oxide film and the duct, and solidifies and shrinks due to the solidification shrinkage of the aluminum solidified in the ring itself. The high-strength aluminum becomes smaller and becomes stronger than the adhesive force from the inner surface of the duct, and peels off in an annular shape, which tends to be a thick film piece. Moreover, since it is an oxide, it does not melt even if it is reheated to a temperature higher than the melting point of molten aluminum. Therefore, when the duct is heated again by the heater and the supply of molten aluminum is started, the thick film pieces of oxide of molten aluminum are separated into the molten aluminum and float as solids.

  Industrially, in order to supply molten aluminum in the atmosphere, the molten aluminum adheres to the inner surface of the duct and is oxidized when the molten aluminum is passed through the duct or stopped while the duct is heated with a heater. It is unavoidable to do. Then, in order to avoid that the thick film piece of the molten aluminum oxide floats in the molten aluminum, it is conceivable to prevent the molten aluminum adhering to the inner surface of the duct from being oxidized.

  As one of the measures, it can be considered that the duct is constantly filled with an inert gas, and molten aluminum adhering to the inner surface of the duct is prevented from coming into contact with air. However, in order to continuously fill the inside of the duct with an inert gas, it is necessary to continuously supply nitrogen gas or argon gas into the duct, which requires an inert gas supply source and a device for recovering it. Is a big issue.

JP 2009-012024 A JP 2006-341281 A JP 05-285638 A Japanese Patent Laid-Open No. 05-042357

  In view of the problems in the conventional molten aluminum supply apparatus and the molten aluminum supply method described above, the present invention allows the oxide of molten aluminum adhered to the inner surface of the duct when the molten aluminum is stopped to be obtained by the subsequent molten aluminum. An object of the present invention is to provide a molten aluminum supply device that peels off from the inner surface of a duct at the start of supply and does not float in molten aluminum as a thick film piece, and a supply method therefor.

  The inventors of the present invention have studied a means that does not mix the molten aluminum oxide pieces adhering to the inner surface of the duct into the supplied molten aluminum regardless of the supply of the inert gas into the duct. As a result, when the molten aluminum supply is stopped, even if the temperature is lower than the melting point of the molten aluminum, the molten aluminum oxide is peeled off from the inner surface of the duct by keeping the duct at a certain temperature. Focused on not having.

  The present invention has been made with such attention of the present inventors. The gist is that when supplying molten aluminum to the transport destination through the duct 1 heated by the heater 9, the oxide of molten aluminum adhering to the inner periphery of the duct 1 does not peel off when the supply of the molten aluminum is stopped. There is to keep the temperature warm.

That is, in the apparatus for supplying molten aluminum to the transport destination through the duct 1, the molten aluminum supply apparatus according to the present invention keeps the molten aluminum in the duct 1 in a molten state when supplying the molten aluminum to the transport destination through the duct 1. The heating duct 1 is heated to a temperature equal to or higher than its melting point, and when the hot water supply is stopped without supplying molten aluminum, the temperature inside the duct 1 is equal to or lower than the melting point of the molten aluminum and the oxide of molten aluminum adhering to the inner periphery peels off. It is provided with a heater 9 that keeps the temperature at a temperature that does not. Specifically, a heater 9 is provided that keeps the inside of the duct 1 at a temperature not higher than the melting point of the molten aluminum and not lower than 300 ° C. and not higher than 500 ° C. when hot water supply is stopped without supplying molten aluminum.

Furthermore, the molten aluminum supply method according to the present invention is a method for supplying molten aluminum to the transport destination through the duct 1. When the molten aluminum is supplied to the transport destination through the duct 1, the molten aluminum in the duct 1 is kept in a molten state. As described above, the heating duct 1 is heated to a temperature equal to or higher than its melting point by the heater 9, and the temperature inside the duct 1 is equal to or lower than the melting point of the molten aluminum by the heater 9 when the hot water supply is stopped without supplying molten aluminum. The temperature is maintained at a temperature at which the molten aluminum oxide does not peel off. Specifically, when the hot water supply is stopped without supplying molten aluminum, the heater 9 keeps the inside of the duct 1 at a temperature not higher than the melting point of the molten aluminum and not lower than 300 ° C. and not higher than 500 ° C.

  As described above, according to the inventor's attention, the oxide containing solidified aluminum from the inner surface of the duct can be maintained at a certain temperature even at a temperature below the melting point of molten aluminum. It was found that no peeling occurred. Therefore, when the hot water supply is stopped without supplying molten aluminum, that is, when the molten aluminum is waiting for hot water supply, the temperature inside the duct 1 is equal to or lower than the melting point of the molten aluminum by the heater 9 and is 300 ° C or higher, more preferably 350 ° C or higher. Keep warm. Thereby, the oxide of the molten aluminum adhering to the inner periphery of the duct 1 can be prevented from peeling off and floating on the molten metal in the duct 1.

  On the other hand, when the hot water supply is stopped without supplying molten aluminum, that is, when the molten aluminum adheres in the duct 1, the heater 9 heats the inside of the duct 1 to a temperature exceeding the melting point (660 ° C.) of aluminum, for example, about 700 ° C. The molten aluminum adhering in the duct 1 becomes the same state as the inner surface of the duct 1 is melt-dip-plated, and an aluminum oxide layer is deposited on the inner surface of the duct 1. When the molten aluminum is supplied with hot water or stopped, the inner diameter of the duct 1 gradually becomes thinner due to the lamination of the molten aluminum and the oxide film, and the flow resistance of the duct 1 increases. When the supply of molten aluminum is started, the flow rate of molten aluminum is reduced. Therefore, in a standby state when hot water supply is stopped without supplying molten aluminum, the temperature inside the duct 1 is set to a temperature that is less than the melting point of the molten aluminum by the heater 9 at a temperature at which the molten aluminum is hardly oxidized, specifically 500 ° C. or less, more preferably From the oxidation experiment of molten aluminum, when the temperature is set to 450 ° C. or higher, the surface becomes milky white and the oxidation progresses remarkably.

  As described above, in the molten aluminum supply apparatus and the molten aluminum supply method according to the present invention, the molten aluminum oxide lump can be obtained simply by keeping the inside of the duct 1 at the required temperature by the heater 9 when the hot water supply is stopped without supplying molten aluminum. It is possible to prevent the pieces from floating in the molten aluminum in the duct 1. Compared to means such as supplying an inert gas into the duct 1, the structure and control are simple and easy because the heater 9 for keeping the duct 1 warm can be used simply to control the energization. Can be implemented.

It is sectional drawing which shows one Example of the supply apparatus of the molten aluminum which uses the induction | guidance | derivation electromagnetic pump for annular molten aluminum of the external form by this invention. It is sectional drawing which shows the other Example of the supply apparatus of the molten aluminum which uses the induction | guidance | derivation electromagnetic pump for annular molten aluminum of the external form by this invention. It is sectional drawing which shows the other Example of the supply apparatus of the molten aluminum using the induction | guidance | derivation electromagnetic pump for immersion type annular molten aluminum by this invention.

In the present invention, the object is achieved by keeping the temperature inside the duct 1 at a required temperature, that is, a temperature below the melting point of the molten aluminum at 300 ° C. or more by the heater 9 when the hot water supply is stopped without supplying molten aluminum. I tried to do it.
Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

FIG. 1 shows an embodiment of an externally supplied molten aluminum supply device according to the present invention, and particularly an embodiment in which molten aluminum is conveyed to a conveyance destination using an annular induction electromagnetic pump for molten aluminum.
A hot water supply opening is opened on an oblique wall surface 13 near the bottom of the molten aluminum tank 11 containing the molten aluminum 12, and the pump side straight upwards obliquely upward toward the hot water supply direction through a flange-like joint to the hot water supply opening. Duct 1 is connected. Furthermore, a hot water supply side duct 1 ′ bent downward is connected to the pump side duct 1 via joints 5, 5 ′ such as flange joints. The hot water supply side duct 1 ′ is pressed against the pump side duct 1 by a spring or the like (not shown), and the joints 5 and 5 ′ are pressed by heat resistant gaskets inserted between the joints 5 and 5 ′. Sealability is ensured. These ducts 1, 1 ′ are made of a heat-resistant and corrosion-resistant material such as ceramic, and a heater 9 is wound on the outside for heat insulation so as to be heated to a temperature higher than the melting point of molten aluminum. It has become.

  Around the pump-side duct 1 on the front side, an inductor 14 in which a coil is wound around a magnetic yoke is disposed. Further, a core 2 made of a magnetic cylinder is disposed in the pump side duct 1 so that the central axes thereof coincide with each other. The core 2 is accommodated in a cylindrical protective tube 3 whose both ends are closed, and is not in direct contact with the molten aluminum in the pump side duct 1. The protective tube 3 is made of a heat-resistant and corrosion-resistant material such as ceramic, and a ceramic fiber such as alumina or magnesia or a filler 8 such as ceramic powder is filled around the core 2 therein as a cushioning material. Has been.

  A flange 6 extends around one end of the protective tube 3 near the hot water supply side duct 1 ', and a portion near the outer periphery of the flange 6 connects the pump side duct 1 and the hot water supply side duct 1'; Sandwiched between 5 '. Thereby, the core 2 is held so as to be positioned at the center of the pump-side duct 1. The pump side duct 1 and the hot water supply side duct 1 ′ are heated by a heater 9 made of a heat retaining micro heater provided on the outer periphery thereof. The flange 6 is provided with a plurality of arc-shaped passage holes 7 that serve as passages for the molten aluminum 12.

When the molten aluminum is supplied to the transport destination through the duct 1, the heater 9 in such a molten aluminum supply device heats the heating duct 1 to a temperature equal to or higher than the melting point of the molten aluminum, specifically to a temperature around 700 ° C. Further, the heater 9 has a temperature not higher than the melting point of the molten aluminum in the duct 1 when hot water supply is stopped without supplying molten aluminum, and the temperature of the molten aluminum is not less than 300 ° C. It is kept at a temperature of 350 ° C. or higher, which is a temperature that does not peel at all from the adhering surface even when the solidification shrinks.

  Thereby, when supplying molten aluminum to a conveyance destination through the duct 1, the molten aluminum in the duct 1 maintains a molten state. On the other hand, when hot water supply is stopped without supplying molten aluminum, that is, when hot water supply is waited, the heater 9 has a temperature equal to or lower than the melting point of molten aluminum, and the temperature inside the duct 1 does not peel off the oxide of molten aluminum adhering to the inner periphery. Keep warm.

Next, the molten aluminum supply method including the operation of the induction electromagnetic pump used for the molten aluminum supply device will be specifically described.
As shown in FIG. 1, when the supply of molten aluminum is stopped and in the supply standby state, which is a preparation stage for supply, the liquid level of molten aluminum 12 in the pump-side duct 1 is guided. Maintain the height of the child 14. At this time, the heater 9 keeps the inside of the duct 1 at a temperature of 300 ° C. or higher and 500 ° C. or lower, more preferably 350 ° C. or higher and 450 ° C. or lower .

  When supply of molten aluminum is started from this state, the inside of the duct 1 is heated by the heater 9 to a temperature equal to or higher than the melting point of the molten aluminum, specifically to a temperature around 700 ° C., and the molten aluminum in the duct 1 is heated. Is in a dissolved state. Next, the inductor 14 is energized, a moving magnetic field is generated in the pump-side duct 1, and a thrust necessary for supply is given to the molten aluminum 12 therein. Then, the molten aluminum 12 in the pump side duct 1 flows over the joint between the hot water side duct 1 ′ and flows into the hot water side duct 1 ′, and the molten aluminum 12 is supplied.

  Thereafter, when the energization to the inductor 14 is stopped and the supply of the molten aluminum 12 is stopped, the liquid level of the molten aluminum 12 in the pump side duct 1 returns to the original height shown in FIG. When supplying the molten aluminum continuously, the duct 1 is not cooled, but is kept heated to a temperature not lower than the melting point of the molten aluminum, specifically, a temperature around 700 ° C. The molten state of the molten aluminum 12 is maintained. In this state, the molten aluminum is supplied continuously or repeatedly.

Thereafter, when the supply of molten aluminum is stopped and the supply standby state is set for a while, in addition to stopping the energization to the inductor 14, the output of the heater 9 is lowered, and the inside of the duct 1 is kept at 300 ° C. or higher. The standby state is set at a temperature of 500 ° C. or lower, more preferably 350 ° C. or higher and 450 ° C. or lower .

  FIG. 2 is a sectional view showing another embodiment of the electromagnetic pump for molten aluminum according to the present invention. In the embodiment shown in FIG. 2, the lower end of the pump-side duct 1 is inserted into the liquid surface of the molten aluminum 12 in the molten aluminum tank 11. In this example, the liquid level of the molten aluminum 12 does not reach the inductor 14. Therefore, an auxiliary means such as a decompression means is necessary so that the liquid level of the molten aluminum 12 reaches the inductor 14 during operation. Other than that, it is almost the same as that shown in FIG. 1, and the same portions are given the same reference numerals. Since the details overlap, description is omitted.

  FIG. 3 is a sectional view showing another embodiment of the electromagnetic pump for molten aluminum according to the present invention. The embodiment shown in FIG. 3 is an example of an immersion electromagnetic pump for annular molten aluminum. In this type of induction electromagnetic pump for annular molten aluminum, the inductor 14 is housed in a protective case 16 made of a material having heat resistance and corrosion resistance such as ceramic, and almost the entire pump portion is contained in the molten aluminum 12. I'm immersed. There is a hole for introducing molten aluminum at the center of the lower end of the protective case 16, and the lower end of the pump side duct 1 is joined to this portion. This is a form in which molten aluminum is pumped into the duct 1 from the hole at the lower end of the duct 1. The protective tube 3 is suspended from the connection portion between the pump side duct 1 and the hot water supply side duct 1 ′ by the flange 21 to the height of the inductor 14. The connection is closed by a longitudinal lid 22 and a lateral lid 22 '. The core 2 is suspended from the longitudinal lid 22 to the height of the inductor 14 by a rod 23. In addition, the structure of the electromagnetic pump itself and the connection of the ducts 1 and 1 'are basically the same as those shown in FIG. 9, and the same portions are denoted by the same reference numerals. Since the details overlap, description is omitted.

  In the above-described embodiments, the molten aluminum electromagnetic pump is used as the power for supplying molten aluminum. However, the present invention is not limited to this, and, for example, gravity from a molten aluminum tank through a duct is used. Of course, the present invention can be applied to one using a molten aluminum supply means using a duct so that molten aluminum is supplied to a target supply destination.

  The molten aluminum supply apparatus and supply method according to the present invention can be applied to a molten aluminum supply system for precision casting in the field of die casting and the like. Moreover, since the structure and control are simple and can be carried out easily, intermittent supply of a fixed amount of molten aluminum can be easily applied.

1 Pump side duct 1 'Hot water supply side duct 9 Heater 12 Molten aluminum

Claims (3)

In the molten aluminum supply device that supplies molten aluminum to the transport destination through the duct 1, when the molten aluminum is supplied to the transport destination through the duct 1, the molten aluminum in the duct 1 is heated to a temperature equal to or higher than its melting point so as to maintain a molten state. An apparatus for supplying molten aluminum, comprising: a heater 9 that heats the duct 1 and keeps the inside of the duct 1 at a temperature of 300 ° C. or higher and 500 ° C. or lower when hot water supply is stopped without supplying molten aluminum. The molten aluminum supply apparatus according to claim 1, further comprising a heater (9) that keeps the inside of the duct (1) at a temperature of 350 ° C or higher and 450 ° C or lower when hot water supply is stopped without supplying molten aluminum. In the molten aluminum supply method for supplying molten aluminum to the transport destination through the duct 1, when the molten aluminum is supplied to the transport destination through the duct 1, the heater 9 exceeds the melting point so that the molten aluminum in the duct 1 remains in a molten state. A method for supplying molten aluminum, characterized in that the heating duct 1 is heated to a temperature and the inside of the duct 1 is kept at a temperature of 300 ° C. or more and 500 ° C. or less by a heater 9 when hot water supply is stopped without supplying molten aluminum.

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