WO2011052138A1

WO2011052138A1 - Molten metal supply device and method for cleaning duct thereof

Info

Publication number: WO2011052138A1
Application number: PCT/JP2010/006000
Authority: WO
Inventors: 邦明三浦; 信浅葉; 辰雄町田; 一雄佐藤; 眞水庭; 辰男桜井; 福治永盛; 孝一百目鬼; 理小滝
Original assignee: 助川電気工業株式会社
Priority date: 2009-10-29
Filing date: 2010-10-07
Publication date: 2011-05-05
Also published as: KR20120084661A; KR101680919B1; JP2011115844A; JP5113866B2

Abstract

The disclosed molten metal supply device supplies a set amount of molten metal (12) each repetition of a short cycle through a simple operation, and enables the detachment of the oxide of the molten metal (12) adhered to the inner surface of a duct. The molten metal supply device, wherein the duct (1) is provided with an inductor (14), applies thrust to the molten metal (12) within the duct (1) by means of said inductor (14), thus supplying said molten metal (12), and is provided with: a hot-liquid supply inductor (14) for supplying by applying thrust to the molten metal (12) within the duct (1); and a startup inductor (24) that has the heat resistance needed to pump the molten metal (12) within the duct (1) to the height of the hot-liquid supply inductor. The startup inductor (24) is disposed at a lower position than the liquid level of the molten metal (12). Furthermore, the oxide of the molten metal (12) adhered to the inner surface of the duct (1) is forcibly detached by means of the hot-liquid supply inductor (14) and the startup inductor (24) supplying the molten metal (12) to the transportation destination and being able to drive the molten metal (12) in the opposite direction.

Description

Molten metal supply apparatus and duct cleaning method thereof

The present invention relates to a molten metal supply apparatus using an induction electromagnetic pump for molten metal used for conveying molten metal such as molten aluminum and molten zinc, and in particular, provided with two stages of inductors, Molten metal supply device that uses the inductor to pump up the molten metal level to the height at which the thrust of the upper hot water inductor acts, and then to supply the molten metal as needed by controlling the energization of the hot water inductor. And a method for cleaning a duct for supplying molten metal.

For example, in the field of casting or the like, an electromagnetic pump for molten metal is used to convey molten aluminum or the like by applying a thrust to the molten metal by electromagnetic induction. Such an electromagnetic pump for molten metal 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 magnetic yoke, and thrust is applied to the molten metal to supply it. Is the mainstream.

Such an induction type electromagnetic pump is described in, for example, Japanese Patent Application Laid-Open No. 2006-341281. A tubular duct through which molten metal flows is surrounded by an inductor having a coil wound around a yoke, and a magnetic core serving as a magnetic path of a magnetic field generated by the inductor is disposed inside the tubular duct. The core is covered with a cylindrical protective tube having heat resistance and corrosion resistance. The flow path of the molten metal is a cross-sectional annular portion formed between the tubular duct and the protective tube therein, and has a structure that generates a moving magnetic field in this portion and gives thrust to the molten metal. Due to its flow path shape, this type of electromagnetic pump is also called an annular flow path type electromagnetic pump.

FIG. 8 shows a conventional example of a molten metal supply apparatus using the above-described electromagnetic pump for molten metal, and is a general one for conveying molten aluminum or molten zinc.
The lower end of the pump side duct 1 is inserted into the liquid surface of the molten metal 12. A hot water supply side duct 1 ′ is connected to the pump side duct 1 via

joints

5 and 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, 5' are inserted by heat resistant gaskets inserted between the joints 5, 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 that the temperature is higher than the melting point of the molten metal 12. It has become.

Around the pump side duct 1 on the front side, an inductor 14 in which a coil 16 is wound around a magnetic yoke 15 is disposed. In the pump side duct 1, a core 2 made of a cylindrical body made of a magnetic material is disposed 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 metal 12 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

heaters

9, 9 ′ made of a heat retaining microheater and the like provided on the outer periphery thereof to prevent the molten metal 12 from solidifying. The flange 6 is provided with a plurality of arc-shaped passage holes 7 serving as passages for the molten metal 12.

In such a type of molten metal supply device, the liquid level of the molten metal 12 does not reach the inductor 14 before the operation of the inductor 14 is started. Therefore, when the molten metal 12 is supplied, the liquid level of the molten metal 12 in the duct 1 reaches the inductor 14, and the molten metal in the duct 1 can be given thrust to the molten metal 12 in the duct 1 by the inductor 14. An auxiliary means of holding 12 levels is required.

As an example of the molten metal supply device provided with such auxiliary means, as described in Japanese Patent Application Laid-Open No. 11-10302 cited as Patent Document 4 below, a method of immersing an immersion body in a molten metal tank is used. There is a molten metal feeder. That is, the immersion body is immersed in a molten metal tank containing molten metal, the molten metal in the molten metal tank is pushed up by the volume, and the liquid level of the molten metal in the duct leading to the molten metal tank is increased to the height of the inductor.

As another example, as described in Japanese Patent Application Laid-Open No. 2007-69255 cited as Patent Document 3 below and Japanese Utility Model Laid-Open No. 1-68156 cited as Patent Document 5 below, a method of reducing the pressure of a duct with a vacuum suction pump is used. There is also a molten metal supply apparatus. That is, the inside of the duct is depressurized by a vacuum suction pump, the molten metal in the duct is pulled up to the height of the inductor by atmospheric pressure, and then the molten metal is supplied by controlling energization to the inductor.

However, in the former molten metal supply apparatus in which the immersion body is immersed in the molten metal tank, since a heavy immersion body is handled, a lifting device such as a crane must be equipped, and the equipment becomes large. Further, it is difficult to finely adjust the liquid level of the molten metal in the duct, and it is difficult to meet the demand for supplying a fixed amount of molten metal repeatedly and accurately.

In the latter case, it is necessary to provide a vacuum suction pump for decompressing the inside of the duct, and also to ensure the airtightness of the duct. It becomes complicated. Also, it takes time to connect the vacuum pump to the duct. In addition, every time the molten metal is supplied before the operation, the duct outlet is opened to return the inside of the duct from the vacuum to the atmospheric pressure. Therefore, it is necessary to depressurize the duct every time the molten metal is supplied. Therefore, the supply of molten metal cannot be repeated quickly and repeatedly, and the cycle time of supplying the molten metal becomes long.

Also, in the molten metal supply device using the molten metal electromagnetic pump, when the supply of the molten metal is stopped or the heating of the duct is stopped accordingly, the oxide of the molten metal is generated and adhered in the duct. This molten metal oxide becomes a lump and hinders the flow of the molten metal in the duct, or the oxide lump is conveyed to the intended supply destination, causing problems such as deterioration in casting quality. . For this reason, at the start of the supply of the molten metal, an oxide lump removal operation of this molten metal is required, but this operation is complicated and troublesome.

JP 2009-12024 A JP 2009-6343 A JP 2007-69255 A Japanese Patent Laid-Open No. 11-10302 Public Opening Hei 1-68156 JP-A-62-142066

In view of the problems in the conventional electromagnetic pump for molten metal described above, the present invention provides a simple operation to increase the height of an inductor when supplying molten metal with an inductor disposed on the liquid surface of the molten metal in a molten metal tank. It is possible to raise the liquid level of the molten metal in the duct and maintain the liquid level regardless of the presence or absence of electromagnetic force of the molten metal electromagnetic pump. It aims at providing the molten metal supply apparatus which can be supplied by a cycle. In addition, an object of the present invention is to easily remove the oxide in the duct by utilizing the structure of the molten metal supply device.

In the present invention, in order to achieve the above-described object, a hot water supply inductor 14 for supplying a molten metal 12 in the duct 1 with thrust, and a molten metal in the duct 1 up to the height of the hot water supply inductor 14 are provided. 12 was used, and a riser inductor 24 having heat resistance for maintaining the height was used. As a result, the molten metal 12 can be supplied to the target location through the

ducts

1, 1 ′ at any time only by controlling the energization of the

inductors

14, 24.

That is, in the molten metal supply apparatus according to the present invention, an inductor 14 is provided in the duct 1, and the molten metal 12 is supplied by supplying thrust to the molten metal 12 in the duct 1 by the inductor 14. A hot water supply inductor 14 for supplying a thrust to the molten metal 12 in the duct 1 and supplying the molten metal 12 in the duct 1 to the height of the hot water supply inductor 14 and having a heat resistance for pumping up the molten metal in the duct 1 The riser inductor 24 is disposed at a position lower than the liquid level of the molten metal 12 housed in the molten metal tank.

As the riser inductor 24 having heat resistance, one using an inorganic insulating cable having high heat resistance as a winding can be cited. This inorganic insulated cable is a so-called sheathed cable in which a conductive wire is housed in a metal sheath such as a stainless tube, and an inorganic insulating powder such as magnesia powder is filled between the conductive wire and the sheath. A winding is constituted by this inorganic insulated cable to form a coil 26, and a yoke 25 is attached to the outside thereof to constitute a rising inductor 24. The rising inductor 24 made of an inorganic insulated cable has high heat resistance and can be used at high temperatures. For example, when the metal is aluminum, it can be used at around 800 ° C., which is higher than its melting point. For this reason, the riser inductor 24 can be used by being disposed at a position lower than the liquid level of the molten metal 12 stored in the molten metal tank, without cooling without the cooling means.

Since the inorganic insulated cable has a larger diameter than that of a normal cable as a whole, the number of turns of the coil 26 of the riser inductor 24 wound thereby is set to be smaller than the number of turns of the coil 16 of the hot water supply inductor 14. However, the current supplied to the coil 26 of the startup inductor 24 is made larger than that to the current supplied to the coil 16 of the hot water supply inductor 14. This ensures a sufficient magnetic flux density to pump the molten metal 12 into the duct 1.

The riser inductor 24 is subjected to energization control in conjunction with the sensor 19 for detecting the liquid level of the molten metal 12 in the duct 1 or the

sensors

13, 23, 23 ', so that the molten metal in the duct 1 is controlled. It can be controlled so that the level of 12 is always maintained up to the height of the inductor 14 for hot water supply. Further, if the electromagnetic force of the hot water supply inductor 14 is increased while weakening the electromagnetic force of the riser inductor 24 so as to maintain the position of the sensor 19 that detects the liquid level, the electromagnetic force of the riser inductor 24 is increased. Even when the force is zero, the liquid level can be maintained only by the electromagnetic force of the hot water supply inductor 14. Of course, it goes without saying that the liquid level can be maintained without making the electromagnetic force of the rising inductor 24 zero. Further, when the supply of the molten metal 12 is stopped, the molten metal 12 flowing from the pump side duct 1 toward the hot water supply side duct 1 ′ is supplied by energizing the rising-up inductor 24 with a three-phase alternating current in reverse phase. It is also possible to stop the flow of the molten metal 12 by braking.

Furthermore, in the present invention, in the above-described molten metal supply apparatus, a structure having two-stage inductors of a hot water supply inductor 14 and a rising inductor 24 is used, and the

inductors

14 and 24 are supplied with molten metal. Driven in the opposite direction, the inside of the duct 1 can be cleaned. Since the above-described molten metal supply apparatus has the riser inductor 24, the riser inductor 24 can pump up the molten metal 12 in the duct 1 from the molten metal tank. In this state, the hot metal inductor 14 and the riser inductor 24 are driven in a direction opposite to the direction in which the molten metal 12 is supplied to the conveyance destination, whereby the oxide of the molten metal 12 adhered to the inner periphery of the duct 1. Forcibly peel off. Further, by discharging the molten metal 12 in the duct 1 to the molten metal tank, the oxide of the molten metal 12 adhering to the inner periphery of the duct 1 can be discharged together with the molten metal 12 to the molten metal tank.

In this case, it is preferable that the length of the core protective tube 3 is equal to the length of the duct 1 or the core protective tube 3 is longer than the duct 1. Otherwise, the reverse flow velocity generated in the return channel formed by the duct 1 and the core protective tube 3 will be slow in the duct 1. By doing so, the oxide of the molten metal 12 can be discharged more efficiently. Moreover, when the front-end | tip of the core protection tube 3 is R shape, it is preferable that the front-end | tip of the core protection tube 3 is made into 1/2 or less of the duct 1 diameter D with a protective case.

As described above, in the molten metal supply apparatus according to the present invention, the molten metal 12 is pumped into the duct 1 by the rising inductor 24 immersed in the molten metal 12, and the level of the molten metal in the duct 1 is induced for hot water supply. By increasing the height to the height of the child 14, the molten metal 12 can be supplied by controlling the electric power to the hot water supply inductor 14. Since the level of the molten metal 12 in the duct 1 can be raised to the height of the hot water supply inductor 14 by the riser inductor 24, the supply of the molten metal 12 by the hot water supply inductor 14 is repeatedly performed in a short cycle. It becomes possible.

Furthermore, since the oxide of the molten metal 12 can be easily peeled off from the inner surface of the duct 1, the flow path in the duct 1 is not narrowed or clogged with oxide. Moreover, it becomes possible to supply the molten metal 12 in which the oxide of the molten metal 12 is not mixed as a lump to the conveyance destination, and for example, the oxide of the molten metal 12 is present in the casting at the supply destination of the molten metal 12. It is possible to improve the quality of the product, such as not mixing.

It is sectional drawing which shows one Example of a molten metal supply apparatus. It is the elements on larger scale of FIG. 1 which shows one Example of a molten metal supply apparatus. It is a control system figure which shows one Example of a molten metal supply apparatus. It is a graph which shows the example of the control output of the inductor for start-up which shows one Example of the molten metal supply apparatus by this invention, and the inductor for hot water supply. It is sectional drawing which shows the other Example of a molten metal supply apparatus. It is sectional drawing which shows the other Example of a molten metal supply apparatus. It is sectional drawing which shows the other Example of a molten metal supply apparatus. It is sectional drawing which shows the prior art example of a molten metal supply apparatus.

In the present invention, there are two stages of a hot water supply inductor 14 for supplying the molten metal 12 as needed and a rising inductor 24 for pumping the molten metal 12 in the duct 1 to the height of the hot water supply inductor 14. The purpose is achieved by providing an inductor. Further, by utilizing the structure of this two-stage inductor, it is possible to reversely drive the hot water supply inductor 14 and the startup inductor 24 while the molten metal 12 in the duct 1 is pumped up. To achieve.
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 a molten metal supply apparatus according to the present invention. This molten metal supply apparatus has two stages of inductors, an upper hot water supply inductor 14 and a lower riser inductor 24. Among these, the configuration of the portion where the upper hot water supply inductor 14 is arranged is basically the same as that of the conventional electromagnetic pump described above with reference to FIG. 8, and the same portions are denoted by the same reference numerals.

The lower end of the pump side duct 1 is inserted into the liquid level of the molten metal 12 stored in a molten metal tank (not shown). Around the portion above the liquid level of the molten metal 12 of the pump-side duct 1 is disposed a hot water supply inductor 14 in which a coil 16 is wound around a magnetic yoke 15. The yoke 15 is fitted on the outer peripheral side so as to surround a portion of the pump side duct 1 that is above the liquid level of the molten metal 12, and a coil 16 constituting a three-phase coil is wound around the yoke 15. Yes.

The core 2 made of a magnetic cylinder is disposed at a position corresponding to the hot water supply inductor 14 in the pump side duct 1 so that the central axis thereof coincides. 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 metal 12 passing through the passage in the pump-side duct 1. A gap is formed between the pump-side duct 1 and the protective tube 3, and this portion becomes a passage for the molten metal 12. 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 ceramic powder is used as a cushioning material between the core 2 and the protective tube 3 therein. Filler 8 is filled.

Furthermore, a rising inductor 24 is disposed around a portion below the inductor 14 of the pump side duct 1. As shown in FIG. 2, similarly to the hot water supply inductor 14, the rising inductor 24 is a magnetic body fitted on the outer periphery of a portion below the inductor 14 of the pump side duct 1. A coil 26 is wound around a yoke 25 made of metal. The coil 26 of the rising inductor 24 is wound around a heat-resistant inorganic insulating cable. The inorganic insulated cable has a structure in which a conductive wire is housed in a sheath made of a stainless steel tube or the like, and the conductive wire and the sheath are insulated by an inorganic insulating powder such as magnesia powder filled therebetween. It is called a so-called sheath cable. Such an inorganic insulated cable has high heat resistance and can withstand a temperature of 800 ° C. However, the number of turns of the coil 26 of the startup inductor 24 is smaller than that of the coil 16 of the hot water supply inductor 14.

A core 22 made of a magnetic cylinder is disposed at a position corresponding to the rise-up inductor 24 in the pump-side duct 1 so that its central axis coincides. The core 22 is housed in a position below the core 2 in the protective tube 3 in which the upper core 2 is housed, so as not to directly contact the molten metal 12 in the pump-side duct 1. It has become. Of course, the portion of the protective tube 3 in which the lower core 22 is accommodated is also filled with a filler 8 such as ceramic fiber such as alumina or magnesia or ceramic powder as a cushioning material between the core 22 and the protective tube 3. Has been. The lower end of the protective tube 3 is closed. In addition, you may comprise the upper core 2 and the lower core 22 as a continuous integral core.

The rising inductor 24 is surrounded by a cylindrical protective case 17 made of heat-resistant ceramic or the like. The upper end opening of the protective case 17 is fixed to the lower end surface of the upper hot water supply inductor 14. The opening at the lower end of the protective case 17 is closely joined to the lower end of the pump-side duct 1, and the inside surrounded by the joint is the introduction of the molten metal 12 at the lower end of the pump-side duct 1. Mouth 18

A hot water supply side duct 1 ′ composed of an L-shaped elbow pipe is closely connected to the upper end of the pump side duct 1 via

joints

5, 5 ′ such as flange joints. A flange 6 extends around one end portion of the protective tube 3 near the hot water supply side duct 1 ′, and a portion close to the outer periphery of the flange 6 connects the pump side duct 1 and the hot water supply side duct 1 ′. It is sandwiched between the

joints

5 and 5 ′. As a result, the

cores

2 and 22 in the protective tube 3 are held so as to be positioned at the center of the pump-side duct 1. The flange 6 is provided with a plurality of arc-shaped passage holes 7 serving as passages for the molten metal 12. The hot water supply side duct 1 ′ is elastically pressed against the pump side duct 1 in front by a spring or the like (not shown). In this state, the sealability of the joints 5 and 5 'is ensured by the heat-resistant gasket inserted between the joints 5 and 5'.

The pump side duct 1 and the hot water supply side duct 1 ′ are made of a heat-resistant and corrosion-resistant material such as ceramic, and molten metal is formed by

heaters

9, 9 ′ made of heat retaining microheaters provided on the outer periphery thereof. Heated to a temperature equal to or higher than the melting point of 12 to prevent the molten metal 12 from solidifying.
A sensor 19 such as a liquid level sensor is provided on the base end side of the hot water supply side duct 1 ′ connected to the pump side duct 1, whereby the liquid level in the pump side duct 1 is detected. Further, a sensor 13 such as a liquid level sensor is provided to detect the liquid level in the molten metal tank. A gate valve 27 is provided at the front end side of the hot water supply side duct 1 ′, and a molten metal supply destination 20 such as a mold is disposed at the tip of the gate valve 27. The molten metal supply destination 20 is provided with a sensor 23 that detects that molten metal has been supplied thereto. The gate valve 27 may be opened and closed by moving a simple triangular or inverted trapezoidal lid up and down. The gate valve 27 is attached to prevent oxidation of the liquid level in the hot water supply side duct 1 ′ and the duct 1, but may be omitted. This gate valve 27 is open during hot water supply.

In such a molten metal supply device, for example, in a state where the molten metal 12 is not pumped up to the height of the hot water supply inductor 14 in the pump-side duct 1 as in the stage before the molten metal 12 supply operation, first, As shown in FIG. 1, a three-phase alternating current is energized in the startup inductor 24 to generate a moving magnetic field in the pump-side duct 1 inside, thereby pumping the molten metal 12 into the pump-side duct 1. In addition, the liquid level of the molten metal 12 in the pump side duct 1 is raised to the height of the hot water supply inductor 14, that is, the height at which the thrust can be exerted on the molten metal 1212 by the hot water supply inductor 14. Although the number of turns of the coil 26 of the riser inductor 24 is small, a large current is passed through the riser inductor 24 by that amount, and the liquid level of the molten metal 12 in the pump-side duct 1 is changed to the hot water supply inductor 14. The magnetic flux density necessary for raising the height to the height of is formed.

Since the winding 26 of the startup inductor 24 is made of a heat-resistant sheath cable, it is suitable for supplying a large current. Further, if a three-phase alternating current having a phase opposite to the above is supplied to the startup inductor 24 before operation, the molten metal 12 can be prevented from entering the pump side duct 1 and a large current can be supplied. Thus, the sheath of the coil 26 is heated by the principle of self-heating of the conductive wire of the coil 26 and electromagnetic induction heating, and the pump-side duct 1 can be preheated. This preheating is performed prior to the pumping of the molten metal 12. Of course, it is needless to say that the pump-side duct 1 can be preheated also by the heater 9.

The sensor 19 detects that the liquid level of the molten metal 12 in the pump-side duct 1 has reached the height of the hot water supply inductor 14 by energizing the startup inductor 24, and the molten metal 12 When the sensor 23 detects that the molten metal 12 is not supplied to the supply destination 20, a three-phase alternating current is energized to the hot water supply inductor 14, and a moving magnetic field is generated in the pump side duct 1. At this time, the gate valve 27 is opened. Thereby, the molten metal 12 in the pump side duct 1 is pumped up, and this molten metal is supplied to the supply destination 20 of the molten metal 12 through the supply side duct 1 ′.

Further, as described later, while raising the liquid level with the riser inductor 24 to the hot water supply inductor 14, the output of the riser inductor 24 is lowered so as to maintain the liquid level detected by the sensor 19. The output of the hot water supply inductor 14 is increased, finally the output of the startup inductor 24 is made zero, the liquid level is maintained only by the output of the hot water supply inductor 14, and further, It is also possible to supply the molten metal 12 to the supply destination 20 simply by adjusting the output. Generally, controllability is better when the output is adjusted using only one output adjuster.

When the supply of the predetermined amount of molten metal 12 to the supply destination 20 is completed, the gate valve 27 is closed and the supply of the molten metal 12 is stopped. Before closing the gate valve 27, the output of the hot water supply inductor 14 is adjusted and the liquid level is returned to the liquid level detection position of the sensor 19, and the startup inductor 24 is energized with an antiphase three-phase alternating current. By doing so, the molten metal 12 flowing from the pump side duct 1 toward the hot water supply side duct 1 ′ can be braked, and the flow of the molten metal 12 can be stopped instantaneously. Thereafter, the hot water inductor 14 is energized so that the liquid level of the molten metal 12 in the pump-side duct 1 is maintained at the height of the hot water inductor 14. In this state, since the liquid level of the molten metal 12 in the pump-side duct 1 is maintained only by energizing the hot water supply inductor 14, the energization of the start-up inductor 24 becomes unnecessary.

Fig. 3 shows a control system for controlling such operation. In FIG. 3, the controller 11 receives the detection signals from the

liquid level sensors

13, 19, 23 and controls the power supply 31, the power supply 32, and the power supply 33 to control the hot water supply inductor 14, the riser inductor 24, the hot water supply induction The child 14 and the gate valve 27 are energized as described above. Thereby, the fixed amount of molten metal 12 is supplied to the supply destination 20 such as a mold that requires the supply of the molten metal 12 each time.

FIG. 4 shows an example of the relationship between the control outputs of the hot water supply inductor 14 and the startup inductor 24. The relationship between the control outputs of the hot water supply inductor 14 and the startup inductor 24 shown in FIG. 4 is a simple linear one, but the startup inductor 24 gradually rises like a sine curve. Needless to say, it is not necessary for the hot water supply inductor 14 to be gradually lowered so that there is no fluctuation of the hot water surface.

At the start of operation, the molten metal 12 in the pump duct 1 is first pumped up to the height of the hot water supply inductor 14 by the output of the startup inductor 24. Thereafter, the output of the hot water supply inductor 14 is gradually increased, and the output of the riser inductor 24 is decreased by that amount, and the liquid level of the molten metal in the pump side duct 1 is maintained while balancing the outputs of both. To maintain. As is clear from the principle of Trichery, if the output of the hot water supply inductor 14 can produce an output equivalent to the atmospheric pressure even if the output of the startup inductor 24 is zero, the specific gravity of the molten aluminum alloy is 2. In the case of 5 g / cm ³ , it is possible to hold up to 4 m. Therefore, if the output of the hot water supply inductor 14 is large, the two

inductors

14 and 24 are controlled. Control is better when only the inductor is controlled.

Thereafter, when the output of the hot water supply inductor 14 is further increased, the molten metal 12 is sent to the hot water supply side duct 1 ′, and the molten metal 12 is supplied from the tip thereof. Thus, after the molten metal 12 in the pump-side duct 1 has been pumped up to the height of the hot water supply inductor 14, the output of the riser inductor 24 is set to zero, and only the output of the hot water supply inductor 14 is liquid. The molten metal 12 is supplied to the supply destination 20 simply by maintaining the position and further adjusting the output of the hot water supply inductor 14.

As described above, the molten metal supply device is used to intermittently supply a fixed amount of molten metal 12 each time to a transport destination such as a die casting device or a gravity casting device. When the molten metal 12 is supplied by driving the hot water supply inductor 14, the duct 1 is heated by the heater 9, and the melting point of the molten metal 12 is higher than the melting metal 12 so that the molten metal 12 passing through the duct 1 does not solidify. The temperature is maintained. On the other hand, when the drive of the hot water supply inductor 14 and the startup inductor 24 is stopped and the supply of the molten metal 12 is stopped, the heating of the duct 1 by the heater 9 is also stopped.

However, the driving of the electromagnetic pump is stopped, the supply of the molten metal 12 is stopped, the heating of the duct 1 by the heater 9 is stopped for a while, and after a while, the duct 1 is heated again by the heater 9 and the electromagnetic pump When the supply of the molten metal 12 is started, an oxide lump of the molten metal 12 may be mixed in the duct 1. This oxide lump of the molten metal 12 hinders the flow of the molten metal 12 in the duct 1 or the oxide lump is conveyed to the intended supply destination, causing problems such as deterioration in casting quality. cause. Therefore, when the supply of the molten metal 12 is started, it is necessary to remove the oxide lump of the molten metal 12.

The inventors of the present invention examined the cause of the oxide lump of the molten metal 12 and found that it was in the following phenomenon. When the molten metal 12 is passed through the duct 1 while the duct 1 is heated by the heater 9 in order to supply the molten metal 12, a film of the molten metal 12 adheres to the inner surface of the duct 1. When supplying the molten metal, the molten metal 12 adhering to the inner surface of the duct is constantly washed by the molten metal 12 passing through the duct 1 and continuously updated in the metallic state. However, when the supply of the molten metal is stopped and the heating of the duct 1 is stopped, the surface of the molten metal 12 attached to the inner surface of the duct 1 comes into contact with air and oxidizes, and an oxide film is formed on the surface. This oxide film peels off from the inner surface of the duct 1 and tends to be a lump. Moreover, since it is an oxide, it does not melt even when reheated to a temperature higher than the melting point of the molten metal 12. Therefore, when the duct 1 is heated again by the heater 9 and the supply of the molten metal 12 is started, the oxide lump of the molten metal floats as a solid in the molten metal 12.

Since the molten metal 12 is supplied, it is inevitable that the molten metal 12 adheres to the inner surface of the duct 1 when the duct 1 is heated by the heater 9 and the molten metal 12 is passed through the duct 1. Then, in order to avoid the oxide lump of the molten metal 12 from floating in the molten metal 12, a measure for preventing the molten metal 12 adhering to the inner surface of the duct 1 from being oxidized can be considered.

As one of the measures, it can be considered that the duct 1 is constantly filled with an inert gas and the molten metal 12 adhering to the inner surface of the duct 1 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 1, and an inert gas supply source and a device for recovering it are required. Equipment becomes large.

In the molten metal supply apparatus described above, the oxide adhered to the inside of the pump-side duct 1 using the above-described structure provided with the two-stage inductors of the startup inductor 24 and the hot water supply inductor 14. Can be washed. For this purpose, the hot-water supply inductor 14 and the startup inductor 24 are reversely driven while the molten metal 12 in the duct 1 is pumped up. An example of this procedure will be described below.

First, by energizing the starting inductor 24, the sensor 19 detects that the liquid level of the molten metal 12 in the pump side duct 1 has reached the height of the hot water supplying inductor 14, and the molten metal When the sensor 23 detects that the molten metal 12 is not supplied to the 12 supply destinations 20, a three-phase alternating current is applied to the hot water supply inductor 14, and a moving magnetic field is generated in the pump side duct 1. Thereby, the molten metal 12 in the pump side duct 1 is pumped up, and this molten metal 12 holds the molten metal 12 through the supply side duct 1 ′.

Thereafter, the startup inductor 24 and the hot water supply inductor 14 are energized so as to generate a moving magnetic field opposite to that at the time of pumping, and the molten metal 12 is returned to the molten metal tank. Thereby, the oxide in the pump side duct 1 is backwashed by the molten metal 12 in the duct 1, and the oxide is excluded in the molten metal 12 of the molten metal tank. Thereafter, the startup inductor 24 is energized, the molten metal 12 is pumped up again into the pump-side duct 1, and the sensor 19 detects that the liquid level of the molten metal 12 has reached the height of the hot water supply inductor 14. In addition, when the sensor 23 detects that the molten metal 12 is not supplied to the supply destination 20 of the molten metal 12, a three-phase alternating current is energized to the hot water supply inductor 14, and a moving magnetic field enters the pump side duct 1. Is generated. Thereby, the molten metal 12 in the pump side duct 1 is pumped up, and this molten metal 12 holds the molten metal 12 through the supply side duct 1 ′. This is repeated several times, and the peeled oxide is removed into the molten metal 12 in the molten metal tank while forcibly peeling the oxide of the molten metal 12 adhering to the inner periphery of the duct 1.

The oxide removed in the molten metal 12 floats on the upper layer of the molten metal 12, and is scraped and discarded. Alternatively, if the oxide in the pump-side duct 1 is cleaned prior to the replacement of the molten metal 12 in the molten metal tank, the oxide can be discarded at the same time as the old molten metal 12 is discarded. And it can prevent that an oxide is mixed with the molten metal 12 supplied next.

As shown in FIG. 2, from the viewpoint of handling, it is preferable that the tip of the protective tube 3 of the core 22 does not protrude from the inlet 18 of the molten metal 12 at the lower end of the pump-side duct 1. However, if the tip of the protective tube 3 of the core 22 is drawn, for example, by −h from the inlet 18 of the molten metal 12 at the lower end of the pump-side duct 1, it reaches the tip of the protective tube 3 of the core 22 from the inlet 18. The channel cross-sectional area of the portion -h is wider than the portion of the core 22 where the protective tube 3 is present, and the flow rate of the molten metal 12 in that portion is reduced. Therefore, when the tip of the core protective tube 3 has an R shape, the reverse injection speed v ′ is maintained to the outside of the pump side duct 1 and the reverse injection effect can be maintained. 1/2 of the inner diameter D of 1 is the limit. Rather, when the tip of the protective tube 3 of the core 22 has an R shape, the tip of the protective tube 3 protrudes from the inlet 18 of the molten metal 12 at the lower end of the pump side duct 1 in the reverse injection speed v ′. Suitable for maintenance. If this protrusion dimension + h is too long, the rise of the oxide due to buoyancy is hindered, so it is preferable to set the protrusion dimension + h to 1/2 or less of the diameter D of the duct 1 from the end of the duct 1.

Next, another embodiment of the molten metal supply apparatus shown in FIG. 5 will be described. The embodiment shown in FIG. 1 is an example in which the molten metal 12 is supplied to the supply destination 20 of the molten metal 12 with the pump side duct 1 standing substantially vertically and the hot water supply side duct 1 ′ being substantially horizontal. On the other hand, in the embodiment shown in FIG. 5, the pump side duct 1 made of a straight pipe and the hot water supply side duct 1 ′ made of an elbow pipe are arranged obliquely about ± 45 °, and the molten metal 12 such as a mold is made of In this example, the molten metal 12 is supplied to the supply destination 20 ′. The startup inductor 24 and the hot water supply inductor 14 provided in the pump side duct 1 are also installed at the same angle as the pump side duct 1. The mold that is the supply destination 20 ′ of the molten metal 12 is driven by the mold driving mechanism 21, and assembly and demolding are performed. Other than this, the configuration of the embodiment shown in FIG. 5 is basically the same as that of the embodiment described above with reference to FIGS. 1 to 4, and the corresponding parts are indicated by the same reference numerals. Detailed description of common corresponding parts is omitted.

Next, another embodiment of the molten metal supply apparatus shown in FIG. 6 will be described. The embodiment shown in FIG. 6 is basically in common with the molten metal supply apparatus of the embodiment described above with reference to FIG. That is, the pump-side duct 1 and the hot water supply-side duct 1 ′ are disposed obliquely by about ± 45 °, and the molten metal 12 is supplied to the supply destination 20 ′ of the molten metal 12 such as a mold. In this embodiment, however, a gate valve 27 for opening and closing the hot water supply side duct 1 ′ is provided in the hot water supply side duct 1 ′ composed of an elbow pipe, and a liquid for detecting the liquid level of the molten metal 12 in the pump side duct 1 is provided there. A sensor 19 such as a surface sensor is provided. In this embodiment, the gate valve 27 is driven to open and close for the fixed supply of the molten metal 12. The other configuration of the embodiment shown in FIG. 6 is basically the same as that of the embodiment described above with reference to FIG. 5, and corresponding portions are denoted by the same reference numerals. Detailed description of common corresponding parts is omitted.

The embodiment shown in FIG. 7 is an example in which the molten metal 12 supply device is applied to a low-pressure casting device. The pump side duct 1 and the hot water supply side duct 1 ′ are provided substantially vertically, and the supply destination 20 ″ of the molten metal 12 as a mold is connected to the upper end of the hot water supply side duct 1 ′. A certain mold is driven and operated by a mold driving mechanism 21 ', and its assembly and demolding are performed. The molten metal 12 is supplied from the lower hot water supply port through the hot water supply side duct 1 ′ to the casting mold 20 ″ to which the molten metal 12 is supplied. The configuration of the embodiment shown in FIG. 1 to 4 are the same as those in the above-described embodiment, and corresponding portions are denoted by the same reference numerals, and detailed description of common corresponding portions is omitted.

The molten metal supply apparatus according to the present invention can supply the molten metal 12 repeatedly only by energization control of the

inductors

14 and 24 without using vacuum suction or an immersion body. It can be used in fields that require the supply of molten metal 12.

DESCRIPTION OF SYMBOLS 1 Pump side duct 1 'Hot water supply side duct 13 Liquid level sensor 14 Hot water supply inductor 19 Liquid level sensor 23 Liquid level sensor 24 Startup inductor

Claims

In a molten metal supply device that provides inductors 14, 24 in the duct 1 and supplies the molten metal 12 by applying thrust to the molten metal 12 in the duct 1 by the inductors 14, 24, the molten metal 12 in the duct 1. A hot water induction inductor 14 for supplying a thrust to the hot water supply inductor 14 and a rising inductor 24 having heat resistance for pumping up the molten metal 12 in the duct 1 up to the height of the hot water supply inductor 14; A molten metal supply device, wherein the riser inductor 24 is disposed at a position lower than the liquid level of the molten metal 12 accommodated in the molten metal tank.
2. The molten metal supply apparatus according to claim 1, wherein the rising inductor is made of an inorganic insulated cable used as a winding.
The molten metal supply apparatus according to claim 2, wherein the startup inductor 24 is an uncooled inductor having no cooling means.
4. The energization control of the hot water supply inductor 14 and the startup inductor 24 is performed in conjunction with a sensor 19 that detects the liquid level of the molten metal 12 in the duct 1. Molten metal supply device.
5. When the supply of the molten metal 12 in the duct 1 is stopped, the molten metal 12 is braked by supplying a current having an opposite phase to the startup inductor 24. Molten metal supply device.
The number of turns of the coil 25 of the riser inductor 24 is made smaller than the number of turns of the coil 15 of the hot water supply inductor 14, and the current supplied to the coil 25 of the riser inductor 24 is supplied to the coil 15 of the hot water inductor 14. The molten metal supply apparatus according to any one of claims 1 to 5, wherein the molten metal supply apparatus is larger than a current to be energized.
The riser 24 raises the liquid level to the hot water supply inductor 14, lowers the output of the riser inductor 24 so as to maintain this liquid level, and increases the output of the hot water supply inductor 14. 7. The hot water supply control is performed by merely increasing and adjusting the output of the hot water supply inductor 14 while maintaining the liquid level mainly by the output of the hot water supply inductor 14. The molten metal supply apparatus as described.
The molten metal according to any one of claims 1 to 7, wherein the hot water supply inductor 14 and the rising inductor 24 can be driven in a direction opposite to that when the molten metal 12 is supplied to the conveyance destination. Feeding device.
The molten metal supply apparatus according to any one of claims 1 to 8, wherein the length of the protective tube 3 of the core 22 is equal to or longer than the length of the duct 1.
When the tip of the protective tube 3 of the core 22 is R-shaped, the retracting dimension −h and the protruding dimension + h of the protective tube 3 are set to be 1/2 or less of the diameter D of the duct 1 from the tip of the duct 1. The molten metal supply apparatus according to any one of claims 1 to 9, wherein:
In a molten metal supply device that provides inductors 14, 24 in the duct 1 and supplies the molten metal 12 by applying thrust to the molten metal 12 in the duct 1 by the inductors 14, 24, the molten metal 12 in the duct 1. A hot water induction inductor 14 for supplying a thrust to the hot water supply inductor 14 and a rising inductor 24 having heat resistance for pumping up the molten metal 12 in the duct 1 up to the height of the hot water supply inductor 14; The riser inductor 24 is disposed at a position lower than the liquid level of the molten metal 12 in the molten metal tank, and hot water is supplied in a state where the molten metal 12 is pumped from the molten metal tank into the duct 1 by the riser inductor 24. By driving the induction inductor 14 and the startup inductor 24 in the opposite direction to the supply of the molten metal 12 to the conveyance destination, the oxide of the molten metal 12 adhering to the inner periphery of the duct 1 is forced. Molten metal characterized by exfoliation Duct cleaning method of feeding device.
Since the oxide of the molten metal 12 adhering to the inner periphery of the duct 1 is peeled off, the liquid level is raised to the hot water supply inductor 14, and then the reverse output is increased and adjusted simultaneously with the riser inductor 24. 12. The method for cleaning a duct of a molten metal supply apparatus according to claim 11, wherein the molten metal 12 is discharged into a molten metal tank.