JP4986733B2 - Electromagnetic pump for molten metal and its operation method - Google Patents

Description

  The present invention relates to an induction electromagnetic pump for molten metal used for transporting molten metal such as molten aluminum and molten zinc and its operation method, and in particular, the supply of molten metal can be stopped immediately when hot water supply is stopped, The present invention relates to an electromagnetic pump for molten metal that can accurately supply a predetermined amount of molten metal and an operation method thereof.

  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. In order to generate a moving magnetic field on the outer periphery of a tubular duct through which molten metal flows, an inductor having a coil wound around a yoke is disposed, and a magnetic core serving as a magnetic path of the magnetic field generated by the inductor inside the tubular duct Is arranged. The core is covered with a cylindrical protective tube having heat resistance and corrosion resistance. Therefore, the flow path of the molten metal becomes an annular portion formed between the tubular duct and the protective tube, and this kind of electromagnetic pump is called an annular flow path type electromagnetic pump.

FIG. 8 shows a conventional example of the above-described electromagnetic pump for molten metal, which is a general one for conveying molten aluminum or molten zinc.
A hot water supply port is opened in an oblique wall surface 13 near the bottom of the molten metal tank 11 containing the molten metal 12, and the pump side is straight and obliquely upward toward the hot water supply direction through a flange-shaped joint. 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 the molten metal. 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 metal 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 or the like provided on the outer periphery thereof to prevent solidification of the molten metal. The flange 6 is provided with a plurality of arc-shaped passage holes 7 serving as passages for the molten metal 12.

In FIG. 9, the lower end of the pump-side duct 1 is inserted into the liquid surface of the molten metal 12 in the molten metal tank 11. In this example, the liquid level of the molten metal 12 does not reach the height of the inductor 14. Therefore, an auxiliary means such as a decompression means is necessary so that the liquid level of the molten metal 12 reaches the height of the inductor 14 during operation. Other than that, it is almost the same as that shown in FIG. 8, and the same portions are given the same reference numerals. Since the details overlap, description is omitted.

  FIG. 10 is an example of an immersion type induction electromagnetic pump for annular molten metal. In this type of induction electromagnetic pump for molten metal, 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 metal 12. I'm immersed. There is a hole for introducing molten metal in 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. The molten metal 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 such an electromagnetic pump for molten metal, when a constant amount of molten metal is intermittently supplied to a die-casting device, a gravity casting device, etc., the flow rate at the start of hot water supply of the molten metal by the molten metal electromagnetic pump is reduced. Instantaneous stopping of flow rate when starting up and stopping hot water supply of molten metal is required. In particular, since the molten metal has viscosity, there is a problem that when the hot water supply is stopped, the molten metal subsequent to the previous molten metal is drawn out by inertia and the hot water supply is not stopped instantaneously.

  In response to such a problem, for example, a molten metal supply device other than an electromagnetic pump is used, but as shown in Japanese Patent Application Laid-Open No. 2003-39160 and Japanese Patent Application Laid-Open No. 2001-293555, a rise of a molten metal duct is performed. There has been proposed a molten metal supply device having a function of stopping the molten metal used. In addition, as disclosed in Japanese Patent Application Laid-Open No. 2001-191173, there has been proposed one provided with a molten metal supply blocking means using a valve.

  However, with the molten metal stop function using the rise of the molten metal duct, etc., it is difficult to ensure a reliable supply stop operation of the molten metal, and even if an attempt is made to stop the supply of the molten metal due to the viscosity of the molten metal. Therefore, it is practically difficult to stop the supply of the molten metal instantaneously. In addition, there is no valve material capable of repeatedly shutting off high-temperature molten metal even in the molten metal supply shut-off means using a valve, so that the life of the valve is short and it is necessary to replace it repeatedly.

JP 2006-341281 A JP 2003-39160 A JP 2001-293555 A Japanese Patent Publication No. 2001-191173

  In view of the problems in the conventional electromagnetic pump for molten metal and its operation method described above, the present invention is that when the supply of molten metal is stopped, the molten metal continues its hot water supply little by little while dragging the subsequent molten metal due to its viscosity. An object of the present invention is to provide an electromagnetic pump for molten metal that can solve the problem, instantaneously shuts off the molten metal when the molten metal is stopped, and enables an accurate amount of hot water, and an operation method thereof.

  In the present invention, in order to achieve the above object, a weir 16 that changes from an upward gradient to a downward gradient in the hot water supply direction is formed in the molten metal supply path from the pump side duct 1 to the hot water supply section that discharges the molten metal. A gas is ejected from the nozzle 17 toward the top of 16 to separate molten metal when hot water supply is stopped.

That is, the electromagnetic pump for molten metal according to the present invention connects a cylindrical hot water supply side duct 1 ′ to a cylindrical pump side duct 1 through which molten metal passes, and moves into the duct 1 on the outer periphery of the pump side duct 1. An inductor 14 for generating a magnetic field is provided, and a core 2 made of a magnetic material that forms a magnetic path of a moving magnetic field generated by the inductor 14 is disposed in the pump-side duct 1. A weir 16 that changes from an upward gradient to a downward gradient in the hot water supply direction is formed in the molten metal supply path from the pump-side duct 1 to the hot water supply portion that discharges the molten metal, and at the top of the weir 16 when supply of the molten metal is stopped A nozzle 17 is arranged to eject gas so as to strike and separate the molten metal at the top of the weir 16 into an upward gradient side and a downward gradient side on both sides thereof . In this case, the gradient between the pump side duct 1 and the hot water supply side duct 1 ′ is ± 7 ° or more.

Furthermore, the operation method of the molten metal electromagnetic pump according to the present invention uses the above-described molten metal electromagnetic pump, and when the supply of molten metal is stopped by stopping energization to the inductor 14, A gas is blown out so as to hit the top, and the molten metal at the top of the weir 16 is separated into an upward gradient side and a downward gradient side on both sides thereof .

  In such an electromagnetic pump for molten metal and its operating method, the weir 16 that changes from the upward gradient to the downward gradient in the hot water supply direction is formed in the molten metal supply path from the pump-side duct 1 to the hot water supply section that discharges the molten metal. When the supply of molten metal is stopped by stopping energization of the inductor 14, the molten metal is caused to flow on both sides of the weir 16 due to the gradient of the weir 16. Further, at this time, since the gas is ejected toward the weir 16, the molten metal is completely separated by the weir 16 by the ejection of the gas. Accordingly, the molten metal is not continuously supplied by inertia, and the supply of the molten metal can be stopped immediately by stopping the electromagnetic pump.

  As described above, in the molten metal electromagnetic pump and its operating method according to the present invention, the supply of the molten metal can be stopped immediately by stopping the electromagnetic pump. An accurate supply amount can be ensured. In addition, since the supply of the molten metal can be reliably stopped simply by ejecting the inert gas from the nozzle 17 instantaneously, the structure and control are simple and can be implemented easily.

In the present invention, the weir 16 is formed in the molten metal supply path from the pump-side duct 1 to the hot water supply section for discharging the molten metal, and the gas is discharged from the nozzle 17 in a timely manner toward the weir 16 at the bottom of the ducts 1 and 1 ′. The purpose was achieved by erupting.
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 external induction electromagnetic pump for molten metal according to the present invention. The structure of the induction electromagnetic pump for molten metal is basically the same as that of the conventional electromagnetic pump described above with reference to FIG. 8, and the same parts are denoted by the same reference numerals.
A hot water supply port is opened in an oblique wall surface 13 near the bottom of the molten metal tank 11 containing the molten metal 12, and a straight pump side duct 1 is connected to the hot water supply port via a flange joint. The hot water supply side duct 1 is inclined so as to gradually become higher in the hot water supply direction on the left side in FIG. 1, and an ascending gradient is formed in the hot water supply direction.

  A hot water supply side duct 1 ′ is connected to the end of the straight pump side duct 1 via joints 5 and 5 ′ such as flange joints. Contrary to the pump side duct 1, the hot water supply duct 1 'is inclined so as to gradually become lower in the hot water supply direction on the left side in FIG. 1, and a downward slope is formed in the hot water supply direction. A weir 16 is formed at the bottom of the connecting portion between the pump side duct 1 and the hot water supply side duct 1 '. The gradient of the ducts 1, 1 ′ on both sides of the weir 16 is reversed. When the gradient of the pump side duct 1 and the hot water supply side duct 1 ′ is tan θ, it is preferable that θ of the pump side duct 1 and the hot water supply side duct 1 ′ is ± 7 ° or more.

  The top of the connection portion between the pump side duct 1 and the hot water supply side duct 1 ′ is closed by a cover plate 19. The cover plate 19 is provided with a nozzle 17 for injecting an inert gas such as Ar gas or N 2 gas toward the weir 16, and an inert gas supply source 20 is connected to the nozzle 17. Yes. The lid plate 19 is provided with a window, and a sensor 18 that detects the presence of the metal through the window and that extends a distance from a metal surface such as a laser sensor is provided. The position where the presence of metal is detected by this sensor is a portion located on the hot water supply side duct 1 ′ side from the weir.

  The ducts 1 and 1 'are made of a heat-resistant and corrosion-resistant material such as ceramic. As shown in FIG. 1, the duct 1, 1 ′ is wound around a heater 9 made of a heat retaining micro heater or the like provided around the duct 1, and is heated to a temperature equal to or higher than the melting point of the molten metal 12 by the heater 9. Solidification due to a temperature drop of the molten metal 12 in the ducts 1, 1 ′ is prevented. Although the heater of the hot water supply side duct 1 ′ is not shown, a heater is also provided here.

  In the pump-side duct 1 on the front side, a core 2 made of a cylindrical body made of a magnetic material is disposed so that its central axis 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 in the pump-side duct 1. The protective tube 3 of the core 2 is made of a heat-resistant and corrosion-resistant material such as ceramic.

  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 hot water supply side duct 1 ′ is pressed against the pump side duct 1 by a spring or the like (not shown), and the flange 6 of the protective tube 3 is sandwiched between the joints 5 and 5 ′ by a gasket and the sealing property is secured. Yes.

  Since the protective tube 3 is a molded body of ceramic or the like, it is preferable that the flange 6 is molded integrally with the protective tube 3 rather than providing the flange 6 as a separate member. In the protective tube 3, in order to hold the core 2 in the center of the protective tube 3 and eliminate rattling due to vibration during operation, a filler such as ceramic fiber such as alumina or magnesia or ceramic powder is used as a cushioning material. 8 is filled. As shown in FIG. 1, in the illustrated embodiment, the end of the protective tube 3 is closed by a heat-resistant and corrosion-resistant end plug 4 such as ceramic. The core 2 and the filler 8 are stored and filled in the protective tube 3 by opening the end plug 4.

  A passage 7 for passing molten metal is provided in a portion closer to the inner periphery than a portion near the outer periphery sandwiched between the joints 5 and 5 ′ of the flange 6. The passage 7 is in the shape of a long hole that is long in the circumferential direction. Between the passages 7, the outer rim is sandwiched between the cylindrical portion which is the main body portion of the protective tube 3 and the joints 5, 5 ′ of the flange 6. This is a spoke-like connecting part that communicates integrally with the shaped part. FIG. 7 is a perspective view showing this relationship, and is a view before the terminal rod 4 is attached.

  As shown in FIG. 1, a cylindrical inductor 14 in which a coil is wound around a magnetic yoke is disposed around a straight pump-side duct 1 in front. By this inductor 14, a moving magnetic field is formed inside the pump side duct 1, and thrust is given to the molten metal in the pump side duct 1. The magnetic core 2 forms a magnetic path of a moving magnetic field on the central axis of the pump-side duct 1, thereby maintaining the magnetic flux density of the moving magnetic field in the pump-side duct 1, The thrust of the molten metal in the duct 1 is ensured.

Next, the operation of this induction molten metal induction pump including molten metal will be described.
As shown in FIG. 1, the liquid level of the molten metal 12 in the pump-side duct 1 is the same level as the liquid level of the molten metal 12 in the molten metal tank 11 when the inductor 14 is not energized. There is. At this time, the height difference between the weirs 16 of the ducts 1 and 1 ′ and the liquid level of the molten metal 12 is h0.

  From this state, the inductor 14 is energized, a moving magnetic field is generated in the pump-side duct 1, a thrust is applied to the molten metal 12 therein, and when the hot water supply is stopped as shown in FIG. When the liquid level of hn exceeds the height of the weir 16 from the steady liquid level −h0 of the molten metal 12, the molten metal 12 flows over the weir 16 and flows into the hot water supply side duct 1 ′ side, and the molten metal 12 is supplied. Is called.

Thereafter, when energization to the inductor 14 is stopped and the supply of the molten metal 12 is stopped, the liquid level of the molten metal 12 in the pump side duct 1 returns to the above-described steady liquid level −h0. As a result, the molten metal 12 in the pump side duct 1 and the hot water supply side duct 1 ′ flows down along the gradient of the respective ducts 1, 1 ′ using the weirs 16 as a trough, and tries to separate the both sides of the weirs 16. . However, the pump side duct 1 is not separated evenly on both sides, and the hydraulic flow path resistance is larger, so the return of the molten metal 12 to the pump side duct 1 is delayed, and the hot water supply side duct 1 ′ The molten metal 12 falling on the surface is dragged by the molten metal 12 and the hot water runs out. At this time, as shown in FIG. 2 (B), when the inert gas is ejected from the nozzle 17 so as to hit the weirs 16 of the ducts 1 and 1 ′ , the molten metal 12 at the top of the weirs 16 rises on both sides. The molten metal 12 that is forcibly separated into the hot water supply side duct 1 ′ is completely separated from the molten metal 12 in the pump side duct 1, and the molten metal 12 from the hot water supply side duct 1 ′ is separated . Supply is stopped instantaneously.

  FIG. 3 is an example of a time chart showing the temporal relationship between the output of the electromagnetic pump and the ejection of the inert gas from the nozzle 17. As shown in this figure, the supply of the molten metal starts when the energization of the dielectric 14 of the electromagnetic pump is started and ends when the energization of the dielectric 14 of the electromagnetic pump is stopped. At this time, the inert gas is ejected from the nozzle 17. Thus, the molten metal is separated in the weirs 16 of the ducts 1 and 1 ′.

  FIG. 4 is a graph showing an example of the relationship between the electromagnetic pump output and the flow rate of molten metal per unit time, and the electromagnetic pump output is shown in terms of the liquid level of the molten metal 12 in the pump-side duct 1. . When the electromagnetic pump output is reduced to hn = h1> h0, the flow rate of molten metal per unit time is as small as Q1, and it takes time to supply a predetermined amount of molten metal. On the other hand, when the electromagnetic pump output is increased to hn = h2> h0, the flow rate of molten metal per unit time increases to Q2, and it does not take time to supply a predetermined amount of molten metal. However, when the output of the electromagnetic pump is increased, as shown in FIG. 5, the rising of the flow rate of molten metal per unit time is steep, but an unstable supply flow rate state due to a so-called transient phenomenon occurs. Therefore, the electromagnetic pump output should be set so that the unstable state of the supply flow rate due to such a transient phenomenon becomes as small as possible.

  In the above-described embodiment, the pump side duct 1 and the hot water supply side duct 1 ′ are provided with reverse gradients, and the weir 16 is provided at the bottom between them. For example, as shown in FIG. It is clear that the same action and effect can be obtained even if a ridge-like weir 16 is provided in a part of the straight pipe. As a matter of course, a reverse gradient is provided on both sides of the weir 16, so that the supplied molten metal can be separated.

  FIG. 6 is a sectional view showing another embodiment of the electromagnetic pump for molten metal according to the present invention. The structure of the molten metal electromagnetic pump is basically the same as that shown in FIG. 1, and the same portions are denoted by the same reference numerals. In order to avoid duplication of the description of the same part, description is omitted and only a different part is demonstrated.

In the molten metal electromagnetic pump according to this embodiment, the pump side duct 1 is connected horizontally to the side surface of the molten metal tank 11, and a hot water supply side duct 1 ′ is connected to the end of the pump side duct 1 such as a flange joint. 5 and 5 'are connected. The hot water supply duct 1 ′ stands up vertically, and a hot water supply block 10 is attached to the upper end thereof. A weir 16 is provided at the bottom of the hot water supply block 10, and an upward slope is formed on the upper surface of the weir 16 toward the hot water supply side duct 1 ′ toward the hot water supply direction, and further, a downward slope is provided on the hot water supply side ahead. Is formed. A nozzle 17 that ejects gas toward the top of the weir 16 is provided.
The operation method of the molten metal electromagnetic pump is basically the same as the molten metal electromagnetic pump described with reference to FIG.

  FIG. 8 is an overall view including the flange 6 of the protective tube 3. The protective tube 3 has a flange 6 at its end, and a molten metal passage 7 is formed in the flange 6 for allowing molten metal to pass therethrough. The protective tube 3 is basically the same as that used in the electromagnetic pump for molten metal described above with reference to FIG.

  In the electromagnetic pump for molten metal and its operation method according to the present invention, it is possible to ensure an accurate supply amount when supplying a certain amount of molten metal intermittently. It can be applied with molten metal supply system. Moreover, since the structure and control are simple and can be carried out easily, intermittent supply of a fixed amount of molten metal can be easily applied.

It is sectional drawing which shows one Example of the induction | guidance | derivation electromagnetic pump for external ring-shaped molten metals by this invention. It is a conceptual diagram which shows the gradient of the bottom part of the connection part of the pump side duct and hot water supply side duct of the induction | guidance | derivation electromagnetic pump for cyclic | annular molten metal shown in FIG. It is a time chart figure of operation | movement of the induction | guidance | derivation electromagnetic pump for annular molten metals shown in FIG. It is a graph which shows the example of the relationship between the electromagnetic pump output of the induction | guidance | derivation electromagnetic pump for cyclic | annular molten metal shown in FIG. 1, and the flow volume per unit time of molten metal. It is a graph which shows the example of the relationship between the electromagnetic pump output of the induction | guidance | derivation electromagnetic pump for cyclic | annular molten metal shown in FIG. 1, and the flow volume per unit time of molten metal. It is sectional drawing which shows one Example of the induction | guidance | derivation electromagnetic pump for external ring-shaped molten metals by this invention. It is a perspective view which shows the protective tube of the core of the induction | guidance | derivation electromagnetic pump for cyclic | annular molten metal shown in FIG.1 and FIG.6. It is sectional drawing which shows the prior art example of the induction | guidance | derivation electromagnetic pump for an external form annular molten metal. It is sectional drawing which shows the other prior art example of the induction | guidance | derivation electromagnetic pump for external molten metal for cyclic | annular molten metals. It is sectional drawing which shows the prior art example of the induction | guidance | derivation electromagnetic pump for immersion-type annular molten metals.

Explanation of symbols

1 Pump side duct 1 'Hot water supply side duct 16 Weir 17 at the bottom of the duct Nozzle

Claims (3)

A cylindrical hot water supply side duct (1 ') is connected to a cylindrical pump side duct (1) through which molten metal passes, and a moving magnetic field is generated in the duct (1) on the outer periphery of the pump side duct (1). An electromagnetic pump for molten metal in which an inductor (14) is provided and a core (2) made of a magnetic material that forms a magnetic path of a moving magnetic field generated in the inductor (14) is arranged in the pump-side duct (1). , A weir (16) that changes from an upward gradient to a downward gradient in the hot water supply direction is formed in the molten metal supply path from the pump-side duct (1) to the hot water supply section that discharges the molten metal. Melting characterized by disposing a nozzle (17) that ejects gas so as to hit the top of (16) and separates the molten metal at the top of the weir (16) into an upward gradient and a downward gradient on both sides thereof Electromagnetic pump for metal. The electromagnetic pump for molten metal according to claim 1, wherein the slope on both sides of the weir (16) is ± 7 ° or more. A cylindrical hot water supply side duct (1 ') is connected to a cylindrical pump side duct (1) through which molten metal passes, and a moving magnetic field is generated in the duct (1) on the outer periphery of the pump side duct (1). An electromagnetic pump for molten metal in which an inductor (14) is provided and a core (2) made of a magnetic material that forms a magnetic path of a moving magnetic field generated in the inductor (14) is arranged in the pump-side duct (1). In the molten metal supply path from the pump-side duct (1) to the hot water supply section for discharging the molten metal, a weir (16) that changes from an upward gradient to a downward gradient in the hot water supply direction is formed. When the nozzle (17) that ejects gas toward the top of the dam is disposed and the supply of molten metal is stopped, gas is ejected from the nozzle (17) so as to hit the top of the dam (16). The molten metal at the top of the A method for operating an electromagnetic pump for molten metal, wherein the operation is separated into a gradient side .

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