Casting device

Abstract

To provide a casting device which uses an electromagnetic pump as a main component and is equipped with a molten metal leak detection mechanism and a heater so as to surround the outer peripheral surface of the upper part of a nozzle on the upper part of an electromagnetic pump, with a configuration in which the detection accuracy of molten metal leaking from between the nozzle and a stalk on the nozzle is high, and the leaked molten metal does not reach or is difficult to reach the heater.SOLUTION: A molten metal leak detection mechanism 40 includes a first electrode plate 41, a first insulating plate 42 placed below the first electrode plate, a second electrode plate 43 placed below the first insulating plate, a second insulating plate 44 placed below the second electrode plate, a sensor 45 detecting whether or not the first electrode plate 41 and the second electrode plate 43 are electrically connected, and a collar part 48 projecting horizontally from the outer peripheral surface of the nozzle 28. The first electrode plate 41 and the first insulating plate 42 have a prescribed clearance with the outer peripheral surface of the nozzle 28, and the second electrode plate 43 and the second insulating plate 44 are extended to contact the outer peripheral surface of the nozzle 28.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a casting apparatus having an electromagnetic pump as a main component.

Background Art

[0002] Electromagnetic pumps that suck up and discharge molten metal by electromagnetic induction action are in practical use. Furthermore, a casting apparatus having an electromagnetic pump as a main component is known (see, for example, Patent Document 1).

[0003] In the electromagnetic pump described in Patent Document 1, the pump shaft is inclined, but those with a vertical pump shaft have also been put into practical use. That is, as shown in FIG. 5, a conventional casting apparatus 100 mainly includes an electromagnetic pump 102 having a nozzle 101 at the upper part, a stalk 103 disposed above the nozzle 101, and a mold 104 disposed above the stalk 103.

[0004] By electromagnetic induction action, the molten metal 105 is sucked up and poured into the cavity 106 of the mold 104 through the nozzle 101 and the stalk 103.

[0005] An enlarged view of part 6 in FIG. 5 is shown in FIG. 6. As shown in FIG. 6, the joint between the nozzle 101 and the stalk 103 is sealed with a sealing material 107. A molten metal leakage detection mechanism 110 is disposed so as to surround the outer peripheral surface of the upper part of the nozzle 101.

[0006] The molten metal leakage detection mechanism 110 includes a first electrode plate 111 that is a ring-shaped disk, a first insulating plate 112, a second electrode plate 113, a second insulating plate 114, and a sensor 115 that measures whether or not the space between the first electrode plate 111 and the second electrode plate 113 is electrically conductive.

[0007] In the molten metal leakage detection mechanism 110, a clearance α is provided between the outer periphery of the nozzle 101 and the first electrode plate 111 etc. to allow the leaked molten metal to pass through. If the sealing material 107 is sound and there is no leakage of the molten metal, the space between the first electrode plate 111 and the second electrode plate 113 is insulated by the first insulating plate 112 and is not electrically conductive.

[0008] Due to changes in the crimping state between the nozzle 101 and the stalk 103 of the electromagnetic pump 102 or the like, the sealing performance of the sealing material 107 may deteriorate. At that time, as shown in FIG. 7, the molten metal 105 leaks through the sealing material 107, and the leaked molten metal 116 electrically connects the first electrode plate 111 and the second electrode plate 113. Then, since the first electrode plate 111 and the second electrode plate 113 are electrically connected, the sensor 115 detects the leakage of the molten metal.

[0009] When the sensor 115 detects the leakage of the molten metal, based on this detection signal, a stop measure for the casting apparatus 100 is taken. Even if the electromagnetic pump 102 stops, it takes a certain amount of time until the pressure of the molten metal 105 drops. Even if the electromagnetic pump 102 stops, the leakage of the molten metal 105 does not stop until the pressure drops, and the leaked molten metal 117 flows down as shown by the imaginary line. This leaked molten metal 117 reacts with the heater 118 and damages the heater 118. The damaged heater 118 needs to be replaced with a new one, which requires replacement work and incurs replacement costs.

[0010] In the midst of the demand for reducing the replacement work and replacement costs, a structure in which the leaked molten metal 116 does not reach or hardly reaches the heater 118 is desired.

[0011] Also, in FIG. 7, at the initial stage of the leakage, the amount of the leaked molten metal 116 is very small. The very small amount of molten metal 116 flows down along the outer peripheral surface of the nozzle 101. When the thickness of this molten metal 116 is smaller than the clearance α, the molten metal 116 may flow down without touching either or both of the first electrode plate 111 and the second electrode plate 113. Even a very small amount of molten metal 116 reaching the heater 118 causes damage to the heater 118. From the viewpoint of protecting the heater 118, it is desired to improve the detection accuracy of the sensor 115.

[0012] Therefore, a structure is desired in which the detection accuracy of the sensor 115 is high and the leaked molten metal 116 does not reach or hardly reaches the heater 118.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0014] An object of the present invention is to provide a structure in which the detection accuracy of leaked molten metal between a nozzle and a stalk is high and the leaked molten metal does not reach or hardly reaches a heater.

Means for Solving the Problems

[0015] The invention according to claim 1 is a casting apparatus including an electromagnetic pump that pumps up molten metal and discharges it upward from an upper nozzle, a stalk placed on the nozzle to guide the molten metal, and a sealing material placed between the stalk and the nozzle. This casting apparatus includes a molten metal leakage detection mechanism that detects molten metal leaked through the sealing material. This molten metal leakage detection mechanism is disposed below the sealing material so as to surround the outer peripheral surface of the upper part of the nozzle. This molten metal leakage detection mechanism includes a first electrode plate, a first insulating plate disposed below the first electrode plate, a second electrode plate disposed below the first insulating plate, a second insulating plate disposed below the second electrode plate, a sensor that detects whether the first electrode plate and the second electrode plate are electrically conductive, and a flange portion that projects horizontally from the outer peripheral surface of the nozzle. The first electrode plate, the first insulating plate, the second electrode plate, and the second insulating plate have a predetermined clearance from the outer peripheral surface of the nozzle. The second insulating plate is placed on the flange portion.

[0016] The invention according to claim 2 is a casting apparatus comprising an electromagnetic pump that pumps up molten metal and discharges it upward from an upper nozzle, a stalk that is placed on the nozzle and guides the molten metal, and a sealing material placed between the stalk and the nozzle. This casting apparatus is provided with a molten metal leakage detection mechanism for detecting molten metal that has leaked through the sealing material. This molten metal leakage detection mechanism is disposed below the sealing material so as to surround the outer peripheral surface of the upper part of the nozzle. The molten metal leakage detection mechanism includes a first electrode plate, a first insulating plate disposed below the first electrode plate, a second electrode plate disposed below the first insulating plate, a second insulating plate disposed below the second electrode plate, a sensor for detecting whether the first electrode plate and the second electrode plate are electrically conductive, and a flange portion that projects horizontally from the outer peripheral surface of the nozzle. The first electrode plate and the first insulating plate have a predetermined clearance from the outer peripheral surface of the nozzle. The second electrode plate and the second insulating plate are extended so as to contact the outer peripheral surface of the nozzle. The second insulating plate is placed on the flange portion.

Advantages of the Invention

[0017] In the invention according to claim 1, the first electrode plate, the first insulating plate, the second electrode plate, and the second insulating plate are configured to have a predetermined clearance from the outer peripheral surface of the nozzle. Moreover, the second insulating plate is placed on the flange portion. The leaked molten metal is accumulated in a space formed with a predetermined clearance with the upper surface of the flange portion as the bottom surface. Through the accumulated molten metal, the first electrode plate and the second electrode plate are electrically conductive, and the leaked molten metal is quickly and surely detected by the sensor.

[0018] That is, by accumulating molten metal above the flange, the detection accuracy of the sensor can be improved. In addition, by preventing the molten metal from flowing directly onto the heater by the flange, the possibility of the molten metal reaching the heater is reduced. Therefore, according to the present invention, there is provided a structure in which the detection accuracy of the molten metal leaking between the nozzle and the stalk is high, and the leaked molten metal does not reach or hardly reaches the heater.

[0019] In the invention according to claim 2, the first electrode plate and the first insulating plate are arranged to have a predetermined clearance from the outer peripheral surface of the nozzle, and the second electrode plate and the second insulating plate are brought into contact with the outer peripheral surface of the nozzle. Then, the second insulating plate is placed on the flange portion. The leaked molten metal is accumulated in a space formed with a predetermined clearance with the upper surface of the second electrode plate as the bottom surface. Through the accumulated molten metal, the first electrode plate and the second electrode plate are electrically connected, and the accumulated molten metal is quickly and surely detected by the sensor.

[0020] In addition, since the molten metal is accumulated on the second electrode plate, the electrical contact between the molten metal and the second electrode plate is improved. By accumulating the molten metal above the second electrode plate, the detection accuracy of the sensor can be further enhanced. In addition, by preventing the molten metal from directly flowing down to the heater by the flange, the possibility of the molten metal reaching the heater is reduced. Therefore, according to the present invention, there is provided a structure in which the detection accuracy of the molten metal leaking between the nozzle and the stalk is high, and the leaked molten metal does not reach or hardly reaches the heater.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0022] Embodiments of the present invention will be described below with reference to the accompanying drawings.

Example

[0023] As shown in FIG. 1, the casting apparatus 10 mainly includes an electromagnetic pump 20 having a pump shaft in the vertical direction (perpendicular to the horizontal plane) and a nozzle 28 at the upper part thereof, a stalk 11 disposed above the nozzle 28, and a mold 12 disposed above the stalk 11.

[0024] The electromagnetic pump 20 includes a base flange 21, a heat conduction pipe 22 extending vertically through the base flange 21, an iron core member 23 housed in the heat conduction pipe 22, a lower coil 24 surrounding the lower part of the heat conduction pipe 22, a lower case 25 suspended from the base flange 21 while surrounding the lower coil 24, an upper coil 26 surrounding the upper part of the heat conduction pipe 22, an upper case 27 placed on the base flange 21 while surrounding the upper coil 26, a nozzle 28 extending upward from the heat conduction pipe 22, a level gauge 29 surrounding the nozzle 28, and an upper flange 30 connected to the upper case 27.

[0025] When an electric current is applied to the lower coil 24, a Lorentz force is generated according to Fleming's left-hand rule, and the molten metal 13 is lifted. Next, when the molten metal 13 reaches near the center of the upper coil 26, if the upper coil 26 is energized and the lower coil 24 is de-energized, the molten metal 13 is lifted up to the level gauge 29. The level of the level gauge 29 reaches the "standby level".

[0026] According to Fleming's left-hand rule, when the current is increased, the Lorentz force increases. When the current in the upper coil 26 is further increased, the molten metal exceeds the level gauge 29, is discharged upward from the nozzle 28, passes through the stalk 11, and is poured into the casting mold 12.

[0027] An enlarged view of a part of FIG. 1 is shown in FIG. 2. As shown in FIG. 2, the joint between the nozzle 28 and the stalk 11 is sealed with a sealing material 31. A molten metal leakage detection mechanism 40 is arranged so as to surround the outer peripheral surface of the upper part of the nozzle 28.

[0028] The molten metal leakage detection mechanism 40 includes a first electrode plate 41 which is a ring-shaped disk, a first insulating plate 42 arranged under the first electrode plate 41, a second electrode plate 43 arranged under the first insulating plate 42, a second insulating plate 44 arranged under the second electrode plate 43, a sensor 45 for detecting whether the first electrode plate 41 and the second electrode plate 43 are electrically conductive, and a flange portion 48 protruding horizontally from the outer peripheral surface of the nozzle 28.

[0029] The first electrode plate 41, the first insulating plate 42, the second electrode plate 43 and the second insulating plate 44 have a predetermined clearance α from the outer peripheral surface of the nozzle 28. On top of that, the second insulating plate 44 is placed on the flange portion 48.

[0030] In FIG. 2, the sealing material 31 is sound and the molten metal 13 does not leak. The first electrode plate 41 and the second electrode plate 43 are in a non-electrically conductive state, and the sensor 45 does not detect molten metal leakage.

[0031] When the sealing performance of the sealing material 31 deteriorates due to a change in the crimping state of the nozzle 28 and the stalk 11 of the electromagnetic pump 10 or the like, the molten metal 13 begins to leak.

[0032] As shown in FIG. 3, the leaked molten metal 46 accumulates in a space formed with a predetermined clearance α with the upper surface of the flange 48 as the bottom surface. The accumulated molten metal 46 electrically conducts the first electrode plate 41 and the second electrode plate 43. The sensor 45 detects that the first electrode plate 41 and the second electrode plate 43 are electrically conductive, and this detection signal is generated.

[0033] That is, by accumulating the molten metal 46 in the space above the flange 48, the detection accuracy of the sensor 45 can be improved. In addition, by preventing the molten metal 46 from flowing directly onto the heater 47 by means of the flange 48, the concern that the molten metal 46 may reach the heater 47 is reduced.

[0034] A modified example of the present invention will be described with reference to FIG. 4. As shown in FIG. 4, the first electrode plate 41 and the first insulating plate 42 have a predetermined clearance α from the outer peripheral surface of the nozzle 28. On the other hand, the second electrode plate 43 and the second insulating plate 44 are arranged such that their inner peripheral surfaces are in contact with the outer peripheral surface of the nozzle 28. Furthermore, the second insulating plate 44 is placed on the flange portion 48.

[0035] The nozzle 28 is made of non-conductive ceramics, and it is electrically acceptable for the second electrode plate 43 to be in contact with the outer peripheral surface of the nozzle 28.

[0036] In FIG. 4, assuming that a part of the molten metal 13 has leaked through the sealing material 31, the leaked molten metal (reference numeral 46 in FIG. 3) accumulates in the space formed by the clearance α with the upper surface of the second electrode plate 43 as the bottom surface. The accumulated molten metal electrically connects the first electrode plate 41 and the second electrode plate 43. The sensor 45 detects that the first electrode plate 41 and the second electrode plate 43 are electrically connected, and this detection signal is generated.

[0037] At this time, the accumulated molten metal lies on the second electrode plate 43 with a width of α. In FIG. 3, the contact area of the second electrode plate 43 with respect to the molten metal 46 is proportional to the thickness of the second electrode plate 43. In contrast, in FIG. 4, the contact area of the second electrode plate 43 with respect to the molten metal is proportional to (the thickness + α) of the second electrode plate 43.

[0038] That is, in the configuration of FIG. 4, the contact area between the molten metal and the second electrode plate 43 increases. When the contact area increases, the frequency of contact with the molten metal increases, and the detection accuracy of the sensor 45 can be further improved. In addition, by preventing the molten metal 46 from flowing directly onto the heater 47 by means of the flange 48, the concern that the molten metal 46 may reach the heater 47 is reduced.

[0039] In the embodiment, the pump shaft is vertical, but it may be inclined as long as it is within the range of 0 to 45° from the vertical axis.

Industrial Applicability

[0040] The present invention is suitable for a casting apparatus having an electromagnetic pump as a main part.

Explanation of Signs

[0041] 10... Casting apparatus, 11... Stock, 12... Mold, 13... Molten metal, 20... Electromagnetic pump, 28... Nozzle, 31... Sealing material, 40... Molten metal leakage detection mechanism, 41... First electrode plate, 42... First insulating plate, 43... Second electrode plate, 44... Second insulating plate, 45... Sensor, 46... Leaked molten metal, 47... Heater, 48... Flange portion, α... Clearance.

Claims

1. In a casting apparatus comprising an electromagnetic pump that pumps up molten metal and discharges it upward from an upper nozzle, a stalk that is placed on the nozzle and guides the molten metal, and a sealing material that is placed between the stalk and the nozzle, the casting apparatus includes a molten metal leakage detection mechanism that detects molten metal leaked through the sealing material, the molten metal leakage detection mechanism is disposed below the sealing material so as to surround an outer peripheral surface of an upper portion of the nozzle, the molten metal leakage detection mechanism includes a first electrode plate, a first insulating plate disposed below the first electrode plate, a second electrode plate disposed below the first insulating plate, a second insulating plate disposed below the second electrode plate, a sensor that detects whether the first electrode plate and the second electrode plate are electrically conductive, and a flange portion that projects horizontally from an outer peripheral surface of the nozzle, the first electrode plate, the first insulating plate, the second electrode plate, and the second insulating plate have a predetermined clearance from the outer peripheral surface of the nozzle, the casting apparatus, wherein the second insulating plate is placed on the flange portion.

2. In a casting apparatus comprising an electromagnetic pump that pumps up molten metal and discharges it upward from an upper nozzle, a stalk that is placed on the nozzle and guides the molten metal, and a sealing material that is placed between the stalk and the nozzle, the casting apparatus includes a molten metal leakage detection mechanism that detects molten metal leaked through the sealing material, the molten metal leakage detection mechanism is disposed below the sealing material so as to surround an outer peripheral surface of an upper portion of the nozzle, the molten metal leakage detection mechanism includes a first electrode plate, a first insulating plate disposed below the first electrode plate, a second electrode plate disposed below the first insulating plate, a second insulating plate disposed below the second electrode plate, a sensor that detects whether the first electrode plate and the second electrode plate are electrically conductive, and a flange portion that projects horizontally from an outer peripheral surface of the nozzle, the first electrode plate and the first insulating plate have a predetermined clearance from the outer peripheral surface of the nozzle, the second electrode plate and the second insulating plate are extended so as to contact the outer peripheral surface of the nozzle, the casting apparatus, wherein the second insulating plate is placed on the flange portion.

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