JP2006341281A - Electromagnetic pump for molten metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic pump for a molten metal in which the molten metal is hardly stagnated in a duct at a holding part of a protective tube of a core 2, scraps such as oxides of the molten metal are hardly generated, and the maintenance such as cleaning is easily performed. <P>SOLUTION: The electromagnetic pump for the molten metal comprises cylindrical ducts 1, 1' to pass the molten metal, an inductor 14 which is provided on the outer circumference of the duct 1 to generate the moving magnetic field in the duct 1, a core 2 which is arranged in the duct 1 to form a magnetic path of the moving magnetic field generated in the inductor 14, and a protective tube 3 provided to cover the core 2. A flange 6 is provided on a part of the protective tube 3 which covers the core 2, and the flange 6 is held by joints 5, 5' or 15 of the ducts 1, 1' to hold the core 2 in the duct 1, and an arc-shaped passage 7 to pass the molten metal is provided in the flange 6 of the protective tube 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 in particular, a protective tube covering the core for fixing a core that forms a magnetic path inside the duct. The present invention relates to an electromagnetic pump for molten metal that has an improved structure for fixing a metal to a duct so that the flow of molten metal does not stagnate and is easy to maintain.

  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. The main type of electromagnetic pump for molten metal is an induction type electromagnetic pump in which a moving magnetic field is generated inside a cylindrical duct by an inductor wound around a magnetic core, and thrust is applied to the molten metal. It is.

  Such an induction type electromagnetic pump is disclosed in Japanese Patent Publication No. 4-52708 and Japanese Patent Laid-Open No. 7-203668. A magnetic material that forms a magnetic path of a magnetic field generated by an inductor inside a tubular duct by arranging an inductor wound around a core for generating a moving magnetic field on the outer periphery of a tubular duct tube through which molten metal flows The core 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.

  In an electromagnetic pump, if a core is not arranged inside the duct, a magnetic path is not formed inside the duct, so the magnetic flux density at the center of the duct becomes extremely small and the thrust at that part becomes low or there is no thrust. End up. For this reason, it is indispensable to arrange the core inside the duct. However, in the casting annular flow type electromagnetic pump provided with a core inside the duct, since there are a spacer provided in the protective tube of the core, a protrusion on the inner periphery of the duct for holding the protective tube against this spacer, etc. The stagnation of the molten metal tends to occur at that portion. For this reason, wastes such as oxides generated on the surface of the molten metal tend to collect, and the removal thereof is troublesome.

  FIG. 8 shows a conventional example of an electromagnetic pump for molten metal, and is a general one for conveying molten aluminum or molten zinc. In the straight duct 1 connected obliquely upward near the bottom of the molten metal tank 11 containing the molten metal 12, the previous duct 1 ′ for hot water supply bent at 90 ° is provided with joints 5, 5 such as flange joints. Connected through '. This duct 1 'is pressed against the duct 1 in front by a spring 10, and the sealability of the joints 5, 5' is ensured by a heat-resistant gasket inserted between the joints 5, 5 '. These ducts 1, 1 'are made of a heat-resistant and corrosion-resistant material such as ceramic.

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

Protruding spacers 18, 18 project from the vicinity of both ends of the protective tube 3. The spacers 18, 18 hit the inner periphery of the duct 1 and hold the core 2 at the center of the duct 1. Furthermore, the spacers 18, 18 at both ends hit the protruding stoppers 19, 19 provided on the inner periphery of the duct 1 and are held at predetermined positions in the longitudinal direction of the duct 1.
The ducts 1 and 1 ′ are heated by a heater 17 made of a heat retaining microheater or the like provided on the outer periphery thereof to prevent solidification of the molten metal.

  In such an induction electromagnetic pump for annular molten metal, the molten metal is likely to stagnate at the positions of the spacers 18 and 18 of the protective tube 3 and the stoppers 19 and 19 of the duct. For this reason, wastes such as molten metal oxides are likely to accumulate at the position indicated by symbol C in FIG. In FIG. 8, only the positions of the upper spacer 18 and the stopper 19 are indicated by the symbol C, but the positions of the lower spacer 18 and the stopper 19 are the same.

  8 is prevented from extending due to thermal expansion in the longitudinal direction of the core 2, and thermal stress is applied to the duct 1 and the core 2 due to a thermal cycle when the duct 1 is heated and cooled. May occur and break. In particular, when a molten metal containing a large amount of magnesium, such as an aluminum alloy for die casting, is transported, a large amount of oxide residue is generated in the duct 1.

Conventionally, nitrogen gas is introduced into the duct 1 to prevent this, and an atmosphere for preventing oxidation is created to suppress generation of oxides of molten metal. However, after flowing the molten metal 12, since the nitrogen gas is flowing into the duct 1 after covering the outlet of the duct 1 ′, air enters before the lid is covered, and this generates oxides. Cannot be completely suppressed.
Further, if oxide residue accumulates at the positions of the spacer 18 and the stopper 19, the duct 1 must be completely disassembled in order to remove it. Troublesome maintenance work such as installation and adjustment is required.

  FIG. 9 shows an example in which the flange 21 is provided at the end of the protective tube 3 and is sandwiched between the duct 1 ′ and the presser lid 20, and the core 2 is arranged and fixed on the central axis of the duct 1. The core 2 is fixed to the presser lid 20 via a rod 22. Other parts are the same as those of the induction electromagnetic pump for annular molten metal shown in FIG. 8, and the same parts are denoted by the same reference numerals.

  In the induction electromagnetic pump for annular molten metal having this structure, the molten metal is liable to stagnate at a pocket-shaped depression formed at the joint portion of the flange 21 and the duct 1 ', that is, at the position indicated by the symbol D in FIG. For this reason, wastes such as oxides of molten metal are likely to accumulate at the position indicated by symbol D in FIG.

  8 and 9 are externally attached induction electromagnetic pumps for annular molten metal, while FIG. 10 is an example of an immersion type induction electromagnetic pump for annular molten metal. In this type of induction electromagnetic pump for annular molten metal, the inductor 14 is housed in a protective cylinder 16 made of a material having heat resistance and corrosion resistance such as ceramic, and the entire portion of the pump is immersed in the molten metal 12. Yes. There is a hole for introducing molten metal in the center of the lower end of the protective drum 16, and the lower end of the 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 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 parts are denoted by the same reference numerals.

Even in the induction electromagnetic pump for annular molten metal having this structure, as in the external induction electromagnetic pump for annular molten metal described with reference to FIG. 9, a pocket-shaped depression formed at the joint between the flange 21 and the duct 1 ′, ie, FIG. The stagnation of the molten metal tends to occur at the position indicated by the symbol E in FIG. For this reason, wastes such as oxides of molten metal are likely to accumulate at the position indicated by the symbol E in FIG.
JP-A-7-203668 JP 2001-121255 A JP 2000-263220 A Japanese Patent Publication No. 4-52708

  In view of the problems in the conventional electromagnetic pump for molten metal described above, the present invention is less likely to cause stagnation of molten metal in the duct at the holding portion of the protective tube of the core 2, accumulation of residue such as oxide of molten metal, In addition, the present invention provides an electromagnetic pump for molten metal that is easy to perform maintenance such as cleaning. Accordingly, it is an object of the present invention to provide an electromagnetic pump for molten metal that is unlikely to generate thermal stress during thermal cycling and is not easily damaged.

  In the present invention, in order to achieve the above object, first, a flange 6 is provided in a part of the protective tube 3 covering the core 2, and this flange 6 is connected to the joints 5, 5 ′ of the ducts 1, 1 ′. Thus, the protective tube 3 containing the core 2 is held in the duct 1. Secondly, an arc-shaped passage 7 through which the molten metal is passed is provided in the flange 6 of the protective tube 3, and the molten metal is allowed to pass therethrough.

  That is, an electromagnetic pump for molten metal according to the present invention includes cylindrical ducts 1, 1 ′ through which molten metal passes, an inductor 14 that is provided on the outer periphery of the duct 1 and generates a moving magnetic field in the duct 1, It has the core 2 which consists of a magnetic body which is arrange | positioned in the duct 1 and forms the magnetic path of the moving magnetic field which generate | occur | produced in the said inductor 14, and the protective tube 3 provided so that this core 2 might be covered. Then, a flange 6 is provided in a part of the protective tube 3 covering the core 2, and the core 2 is held in the duct 1 by sandwiching the flange 6 with the joints 5, 5 ′ or 15 of the duct 1, 1 ′. In addition, a passage 7 through which molten metal passes is provided in the flange 6 of the protective tube 3. The passage 7 through which the molten metal passes is formed by an arc-shaped long hole provided in the flange 6 of the protective tube 3.

  In such an electromagnetic pump for molten metal according to the present invention, the protective tube 3 covering the core 2 is sandwiched between the joints 5, 5 ′ or 15 of the duct 1, 1 ′ by the flange 6 provided in a part thereof, Only one place for fixing the protective tube 3 is required. Further, since the passage 7 through which the molten metal is passed is provided in the flange 6 of the protective tube 3, no pocket-shaped depression is generated in the middle of the molten metal flow path. For this reason, it is difficult to accumulate residue such as molten metal oxide. Even if debris such as molten metal oxide accumulates, since the protective tube 3 is fixed at one location, there is no generation of thermal stress due to temperature rise and fall, and the protective tube 3 and the like are not easily damaged.

  Further, since the fixing portion of the protective tube 3 is a portion of the joint 5, 5 ', 15 of the duct 1, 1', the protective tube 3 can be taken out only by removing the joint 5, 5 'or 15. Alternatively, even if the protective tube 3 is not removed, the dust accumulated in the vicinity of the flange 6 can be removed through the arc-shaped passage 7 of the flange 6 with a scraping bar such as an earpick or a suction pipe without removing the duct 1 '. Maintenance is also extremely easy.

  As described above, in the molten metal electromagnetic pump according to the present invention, debris such as molten metal oxide does not easily accumulate in the ducts 1 and 1 ′, and even if it accumulates, the protection tube 3 is not easily damaged by thermal stress. Furthermore, maintenance such as cleaning of the protective tube 3 is facilitated. Thereby, it can be an electromagnetic pump for molten metal that has few troubles and can be avoided easily.

In the present invention, a flange 6 is provided in a part of the protective tube 3 covering the core 2, and the flange 6 is sandwiched between the joints 5, 5 ′ of the ducts 1, 1 ′. The purpose was achieved by providing a passage 7 through which molten metal passes.
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-type induction electromagnetic pump for molten metal according to the present invention. The configuration of the molten metal induction electromagnetic pump 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 on an oblique wall surface 13 near the bottom of the molten metal tank 11 containing the molten metal 12, and a straight duct 1 is connected to the hot water supply port via a flange-shaped joint 5. The duct 1 is inclined so that the left end side is higher in FIG.

  A hot water supply duct 1 ′ bent at 90 ° is connected to the front end of the straight duct 1 via joints 5 and 5 ′ such as flange joints. FIG. 2 is an enlarged view of the front and rear portions of the joints 5, 5 'of the ducts 1, 1' of FIG. These ducts 1, 1 'are made of a heat-resistant and corrosion-resistant material such as ceramic. As shown in FIG. 1, the ducts 1, 1 ′ are heated by a heater 17 made of a heat retaining micro heater or the like provided around the duct 1, 1 ′ to prevent solidification of the molten metal in the ducts 1, 1 ′. ing.

  As shown in FIGS. 1 and 2, a core 2 made of a magnetic cylinder is arranged in the duct 1 on the near side so that the central axes thereof coincide with each other. The core 2 is housed in a cylindrical protective tube 3 whose both ends are closed, and is not in direct contact with the molten metal in the 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 is extended around one end of the protective tube 3 near the hot water supply duct 1 ′, and a portion near the outer periphery of the flange 6 is a joint 5, 5 ′ connecting the duct 1 and the duct 1 ′. Sandwiched between them. Thereby, the core 2 is held so as to be positioned at the center of the duct 1. The hot water supply duct 1 ′ is pressed against the duct 1 on the front side by a spring 10, and the flange 6 of the protective tube 3 is sandwiched between the joints 5, 5 ′ by a gasket (not shown) and the sealing property is secured. ing.

  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 FIGS. 1 and 2, 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. As shown in FIG. 3, for example, the passage 7 has a long hole shape that is long in the circumferential direction, and a space between the passage 7 is a cylindrical portion that is a main body portion of the protective tube 3 and joints 5 and 5 of the flange 6. This is a spoke-like connecting portion 10 that integrally communicates with the rim-like portion on the outer peripheral side sandwiched by '. As shown in FIG. 4, the cross section of the spoke-like connecting portion 10 is preferably oval or circular so as to reduce the flow resistance of the molten metal as much as possible.

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

  FIG. 5 shows another embodiment of the external induction electromagnetic pump for annular molten metal according to the present invention. In this embodiment, the flange 6 of the protective tube 3 is held by the flange 15 of the duct 1 on the hot water supply side of the molten metal tank 11. That is, the flange 6 of the protection tube 6 is sandwiched between the joint of the duct 1 and the periphery of the hot water inlet opened on the oblique wall surface 13 near the bottom of the molten metal tank 11 with the hot water inlet opened. It is the implementation described above with reference to FIGS. 1 to 4 that the arc-shaped passage 7 of the molten metal is provided on the inner side of the rim-like outer peripheral portion sandwiched between the joint 5 of the flange 6 and the wall surface 13 of the molten metal tank 11. Same as example. Further, the configuration of the other molten metal electromagnetic pump is the same as that of the above-described embodiment. FIG. 5 is preferable because the flange 6 is always immersed in the molten metal and no oxide is generated in the arc-shaped passage 7 of the flange 6. Although not shown, if the duct 1 ′ is lengthened and the arc-shaped flow path 7 of the flange 6 is immersed in the molten metal even in the system of FIG. There is less blockage of the flow path due to objects. For example, as the method, the molten metal 12 in the furnace 11 is raised or a slight electromagnetic force is applied to the electromagnetic pump to fill the arc-shaped flow path 7 of the flange 6 with the molten metal 12.

  FIG. 6 and FIG. 7 are examples of the immersion electromagnetic induction pump for annular molten metal. In this type of induction electromagnetic pump for annular molten metal, the inductor 14 is housed in a protective cylinder 16 made of a material having heat resistance and corrosion resistance such as ceramic, and the entire portion of the pump is immersed in the molten metal 12. Yes. The inductor 14 is insulated by the protective cylinder 16 and the duct 1 so as not to contact the molten metal 12. There is a hole for introducing molten metal in the center of the lower end of the protective drum 16, and the lower end of the duct 1 is joined to this portion. In this form, molten metal is pumped from the lower end of the duct 1. The structure of the electromagnetic pump itself and the connection of the ducts 1 and 1 'are basically the same as those shown in FIGS. 1 and 5, and the same parts are denoted by the same reference numerals.

In the embodiment of the induction electromagnetic pump for annular molten metal shown in FIG. 6, a protective tube is provided between the joint 5 and 5 'between the vertical duct 1 and the hot water supply duct 1' bent halfway at 90 °. 3 is an example in which a portion close to the outer periphery of the flange 6 is sandwiched. On the other hand, in the embodiment of the immersion type electromagnetic induction pump for annular molten metal shown in FIG. 7, the periphery of the hole for introducing the molten metal provided at the center of the lower end of the protective cylinder 16 and the lower end of the duct 1 are provided here. This is an example in which a portion near the outer periphery of the flange 6 of the protective tube 3 is sandwiched between the flange 15 for joining. 6 is an example corresponding to the embodiment of FIG. 1 of the external type, and FIG. 7 is an example corresponding to the embodiment of FIG. 5 of the external type. A molten metal arc-shaped passage 7 is formed in the inner peripheral side of the rim portion of the flange 6 and other configurations are the same as those shown in FIGS. 1 and 5 except for the difference between the immersion type and the external type. It is the same as the electromagnetic pump for molten metal shown in 1.
The flange 6 shown in FIG. 7 is always hidden in the molten metal, and the arc-shaped channel 7 having a narrow channel does not have a channel blockage due to oxide. Although not shown in FIG. 6, if a slight electromagnetic force is generated in the electromagnetic pump so that the flange 6 is hidden by the molten metal, the arc-shaped channel 7 is not blocked by the oxide.

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 principal part expanded sectional view which shows the joint part of the core of the induction | guidance | derivation electromagnetic pump for annular molten metals shown in FIG. 1, and a duct. FIG. 3 is an enlarged sectional view taken along line A-A ′ of FIG. 2. FIG. 4 is an enlarged sectional view taken along line B-B ′ in FIG. 3. It is sectional drawing which shows the other Example of the induction | guidance | derivation electromagnetic pump for the external ring-shaped molten metal by this invention. It is sectional drawing which shows another Example of the induction | guidance | derivation electromagnetic pump for submerged annular molten metals by this invention. It is sectional drawing which shows the other Example of the induction | guidance | derivation electromagnetic pump for immersion type annular molten metals by this invention. 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 Duct 1 'Duct 2 Core 3 Protective tube 5 Duct joint 5' Duct joint 6 Protective tube flange 7 Flange passage 14 Inductor 15 Duct joint

Claims (3)

A cylindrical duct (1), (1 ′) for passing molten metal, an inductor (14) provided on the outer periphery of the duct (1) and generating a moving magnetic field in the duct (1), a duct ( 1) a core (2) made of a magnetic material that forms a magnetic path of a moving magnetic field generated in the inductor (14), and a protective tube (3) provided so as to cover the core (2) The flange (6) is provided in a part of the protective tube (3) covering the core (2), and the flange (6) is connected to the ducts (1), (1 '). By holding the joint (5), (5 '), (15), the core (2) is held in the duct (1) and the molten metal is passed through the flange (6) of the protective tube (3). An electromagnetic pump for molten metal, characterized in that a passage (7) is provided. 2. The electromagnetic pump for molten metal according to claim 1, wherein the arc-shaped passage (7) through which the molten metal passes is formed by an arc-shaped long hole provided in the flange (6) of the protective tube (3). The arc-shaped passage (7) provided in the flange (6) is always filled with molten metal in some form so that no oxide is generated in the arc-shaped passage (7). Or the electromagnetic pump for molten metals of 2.

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