JP4355907B2 - Molten metal filtration filter, molten metal cleaning device, and cleaning method - Google Patents

Description

  The present invention relates to a technique for cleaning a molten metal, and more particularly to a molten metal purifying filter having a function of trapping foreign matter in a molten metal, a molten metal cleaning apparatus and a cleaning method using the filter.

  For example, in a continuous casting line or a die-casting line, a molten metal melted in a melting furnace is transported to a tapping outlet or a hot water outlet through a transport trough. In such a casting line, in addition to the progress of oxidation of the molten metal not only during melting but also during transportation, mixing of refractories also occurs, so a lot of foreign matters such as oxides stay in the molten metal or on the molten metal surface, If the molten metal is poured as it is, the foreign matter remains as inclusions in the cast product, and the casting quality is significantly reduced.

  Therefore, conventionally, in such a casting line, a melt purifying filter is installed in a sluice type at an appropriate location in the above-mentioned transport rod (melt flow path), and a cleaning measure is taken to remove foreign substances such as oxides by this filter. I took it. In this case, in order to suppress clogging of the filter and increase the filtration efficiency, a plurality of types of filters with different coarseness are prepared, and the coarser filter is arranged upstream and the finer filter is arranged downstream. (Patent Document 1, Patent Document 2, etc.).

JP 58-181832 A JP-A-6-63710

By the way, since the conventional filter for melt purification has only a function of stopping the passage of foreign substances contained in the molten metal, that is, it does not have a function of capturing foreign substances, it is pulled up from the molten metal to be replaced. Then, many foreign matters stuck to the front surface of the filter fall on the molten metal, and the molten metal is contaminated again. For this reason, conventionally, the supply of the molten metal to the transport rod has been interrupted and the filter has been replaced.
However, when the supply of molten metal to the transport rod is interrupted in this way, the productivity will decrease by the amount of the interruption, and in addition, for the purpose of ensuring the desired casting quality, the molten metal remaining in the transport rod Must be disposed of, and the molten metal yield will also deteriorate.
In order to deal with the above problem, a plurality of casting lines may be set and used alternately, but in this case, an increase in equipment cost and an increase in maintenance cost due to double investment of equipment cannot be avoided.
The present invention has been made in view of the above-described conventional problems, and the object of the present invention is to provide a filter for purifying molten metal with a high filtration efficiency, which has a function of capturing foreign substances contained in the molten metal. An object of the present invention is to provide a cleaning device and a cleaning method capable of efficiently cleaning molten metal using this filter.

In order to solve the above-described problem, a molten metal cleaning apparatus according to the present invention includes a spacer between a relatively coarse first filter member and a finer second filter member than the first filter member. The present invention is characterized in that a molten metal purifying filter is provided which is integrally formed with a gap corresponding to the plate thickness of the spacer .
In the filter configured as described above, the first filter member having a coarse mesh is arranged in the flow path of the molten metal so that the first filter member faces the upstream side of the molten metal flow, so that most of the foreign matter contained in the molten metal is the first. It passes through the filter member and stops at the front surface of the fine second filter member, and is captured in the gap between the first filter member and the second filter member. Therefore, even if this filter is pulled out from the molten metal, foreign matter falling from the filter is remarkably suppressed.

In order to solve the above-mentioned problems, a first device invention as a molten metal cleaning apparatus includes a filter unit in which the above-described filter is stretched in a holding frame to form a unit, and at least two of the filter units are made of molten metal. Are arranged at intervals along the flow path through which the filter flows, and each filter unit is moved up and down by the driving means, and is installed in a sluice type in the flow path so that each first filter member faces the upstream side. It is possible to do this.
In the molten metal cleaning apparatus configured as described above, the two filter units arranged at intervals along the flow path through which the molten metal flows are alternately installed in the flow path at appropriate timing, thereby The filter can be changed without interrupting the flow.
In the first device invention, the driving means may be configured to rotate the filter unit to the upstream side around a horizontal axis coupled to the upper end portion of the filter unit and to pull it up from the molten metal. By comprising in this way, a filter unit operate | moves so that a molten metal may be poured, and the fall of the foreign material caught by the filter is suppressed further.

In order to solve the above-mentioned problems, a second device invention as a molten metal cleaning device includes a sheet roll in which the above-described filter is continuously wound in a roll shape, a feeding means for supporting the sheet roll, and the sheet roll. And a take-up means for winding up the continuous filter whose direction has been changed by the diverting roller, and is provided at a position above the hot water surface in the flow path through which the molten metal flows. And the winding means are arranged so that the winding means is located upstream of the feeding means, and the turning roller is arranged at the bottom of the flow path. The first filter member is positioned on the winding side of the take-up means so as to face the upstream side.
In the molten metal cleaning apparatus configured as described above, the upstream continuous filter can be quickly updated by operating the winding means at an appropriate timing, and the molten metal flow is interrupted as in the first invention. The filter can be replaced without doing so.
In the second device invention, it is desirable that at least the winding side of the continuous filter is inclined upward toward the upstream side. In this case, the foreign matter trapped by the filter is further dropped. It is suppressed.

In order to solve the above problems, one of the methods for cleaning molten metal according to the present invention is a method for cleaning molten metal according to the first device invention, wherein the surface of the molten metal is downstream of the installation area of the filter unit. The height is monitored, and when the molten metal surface level falls below the set value, the driving means is operated to install two filter units arranged in the flow direction of the molten metal alternately in the flow path. It is characterized by.
Moreover, in order to solve the said subject, the other one of the cleaning methods of the molten metal which concerns on this invention is the method of cleaning molten metal by the said 2nd apparatus invention, Comprising: Than the installation area of a continuous filter The hot water surface height on the downstream side is monitored, and when the hot water surface height falls below a set value, the winding means is operated to update the upstream continuous filter.
The passage resistance of the molten metal that passes through the filter for filtration increases as the amount of foreign matter accumulated on the filter increases, that is, as the filter clogs increase, and the height of the molten metal on the downstream side of the filter changes (decreases) accordingly. ) The molten metal purification method according to the present invention has been made paying attention to this point, and the filter unit is replaced or the continuous filter is renewed according to the molten metal surface height downstream of the filter unit or the continuous filter. Thus, the filter can be replaced at an appropriate timing.

According to the molten metal filtration filter according to the present invention, foreign matter is captured in the gap between the first filter member and the second filter member, so that the falling of the foreign matter when pulled up from the molten metal is remarkably suppressed.
According to the molten metal cleaning apparatus according to the present invention, a plurality of filter units in which the filter is stretched in a holding frame are alternately installed in the flow path, or the continuous filter is fed from a filter roll in which the filter is continuously wound. Can be replaced without interrupting the flow of molten metal, improving productivity as well as achieving a significant improvement in molten metal yield. This is unnecessary and is advantageous in terms of cost.
According to the molten metal cleaning method of the present invention, it is possible to accurately grasp the clogging of the filter and replace it.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a first embodiment of a molten metal cleaning apparatus according to the present invention. In the figure, 1 is a transport rod having a flow path 2 through which a molten metal M flows in a certain direction F, and 10 is a cleaning device according to the present invention. Here, the transport rod 1 has a role of continuously transporting the molten metal M from the melting furnace to the outlet in the continuous casting line, and an amount of the molten metal M corresponding to the amount of molten metal is always supplied into the flow path 2. It has come to be. Therefore, the height of the molten metal M in the flow path 2 is maintained at a substantially constant level during the casting cycle.

  The cleaning device 10 includes a filter unit 12 in which a molten metal filter 11 according to the present invention, which will be described later, is stretched, and a horizontal extending the filter unit 12 in a direction perpendicular to the flow path 2 of the transport rod 1. Drive means 14 for turning around a shaft 13 is provided. Here, the two filter units 12 are arranged at intervals along the flow path 2 of the transport rod 1. Each filter unit 12A, 12B has a stand-by position (solid line position of 12B) pulled up so as to be substantially horizontal above the flow path 2 according to the rotation of the horizontal shaft 13, and the flow path 2 in a sluice type. A swivel motion is performed between the closed position (12A solid line position) installed so as to be closed. Here, the position of the horizontal axis 13 is set so that the filter unit 12 is inclined at a predetermined angle θ with respect to the vertical surface in a state where the tip of each filter unit 12 is in contact with the hot water surface (cuts the hot water surface). Has been.

  Here, a recess 3 is formed on the bottom surface of the flow path 2 of the transport rod 1 to allow the tip of each filter unit 12 to escape. The concave portion 3 includes a curved portion 4 that gradually increases in depth from the upstream side to the downstream side, and a standing wall portion 5 adjacent to the curved portion 4. A position to be brought into contact with the standing wall 5 is a turning end in the closing direction. That is, each filter unit 12 is returned from the closed position to the standby position by the turning motion to the upstream side.

2 and 3, the molten metal filtration filter 11 includes a first filter member 15 having a relatively coarse mesh and a second filter member 16 having a finer mesh than the first filter member 15. . The first filter member 15 and the second filter member 16 are integrally joined via a spacer 17, and a slight gap S corresponding to the plate thickness of the spacer 17 is provided between both the filter members 15 and 16. Is set. The type of the filter material constituting the first filter member 15 and the second filter member 16 is arbitrary, and for example, an aggregate of glass fibers, a ceramic porous body, and the like can be selected.

  The filter unit 12 has the above-described filter 11 stretched inside a rectangular holding frame 18. The holding frame 18 is provided with brackets 19 for inserting the horizontal shaft 13 at both ends of the upper side portion 18a. The horizontal shaft 13 and the bracket 19 are coupled so as not to be rotatable relative to each other by, for example, key means, and the filter unit 12 performs a turning motion in accordance with the rotation of the horizontal shaft 13. On the other hand, the lower side portion 18 b of the holding frame 18 has a curved surface on the lower surface side, and can move smoothly along the curved portion 4 in the concave portion 3 of the flow path 2.

  The drive means 14 is provided independently corresponding to each filter unit 12A, 12B, and each drive means 14A, 14B is connected to a separately provided control means 20 via signal lines 21A, 21B. On the other hand, a hot water level sensor 22 for detecting the hot water surface height of the molten metal M is installed on the downstream side of the installation area of the filter unit 12B disposed on the downstream side. The detection signal of the hot water level sensor 22 is sent to the control means 20 via the signal line 23, and the control means 20 responds to the hot water level detected by the hot water level sensor 22. The operation of each driving means 14A, 14B is controlled. The type of the molten metal surface sensor 22 is arbitrary, and may be a float type provided with a float 22a as shown in the figure, or a non-contact optical type.

Hereinafter, the cleaning method of the molten metal performed using the cleaning apparatus 10 configured as described above will be described.
In continuous casting, filter units 12 (12A, 12B) each having a new filter 11 are prepared, and the coarse first filter 15 constituting each filter 11 faces the upstream side in the closed position. In this way, each filter unit 12 is coupled to the horizontal shaft 13 and is kept waiting at the standby position.
First, one of the two filter units 12A and 12B (here, the upstream filter unit 12A) is swung by the driving means 14 (14A) via the rotating shaft 13, and is shown in FIG. It is installed in the closed position indicated by the solid line.

Thereafter, the molten metal M is supplied from the melting furnace to one end side of the transport rod 1, and the molten metal M flows in the flow path 2 to the outlet port side at the other end side of the transport rod 1 as indicated by an arrow F. At this time, since the hot water outlet is closed by the stopper, the surface height of the molten metal M in the flow path 2 gradually increases, and finally reaches the upper limit level h _U that stabilizes the casting quality. At this stage, the stopper is pulled out from the hot water outlet, the molten metal is discharged into the mold, and continuous casting is started. By the start of this continuous casting, the molten metal level in the flow path 2 is lowered, but since the molten metal M corresponding to the amount of molten metal is supplied to the transport rod 1, the molten metal in the flow path 2 is at the upper limit level h. Maintain a constant level slightly below _U.

  During the hot water preparation and during the hot water supply, the molten metal M flows downstream through the filter unit 12A, and foreign matter contained in the molten metal M is captured by the filter 11 of the filter unit 12A. In this case, since the filter 11 has a double structure in which the first filter member 15 with a coarse mesh and the second filter member 16 with a fine mesh are combined at a slight interval, most of the foreign matter contained in the molten metal M is obtained. Passes through the first filter member 15, stops at the front surface of the fine second filter member 16, and is captured in the gap S between the filter members 15 and 16. And if the quantity of the foreign material caught by the filter 11 increases, the passage resistance of the molten metal M which passes the filter 11 will rise, and according to this, the hot_water | molten_metal surface height of the molten metal M downstream from the installation area of the filter unit 12 is increased. Gradually decreases.

Here, molten metal surface level of the downstream side of the installation area of the filter unit 12 is monitored by a water level sensor 22, the molten metal surface level is a constant value than the lower limit level h _L to stabilize the casting quality When the set value h _s or less is set to the upper level, the drive unit 14B of the downstream filter unit 12B is first actuated by a command from the control device 20, and the filter unit 12B rotates about the horizontal shaft 13. 1 is installed in the closed position indicated by the broken line in FIG. Subsequently, the drive unit 14A of the upstream filter unit 12A is actuated by a command from the control device 20, and the filter unit 12A pivots around the rotating shaft 13 from the closed position to the standby position. At this time, foreign matter is captured in the gap S between the first filter member 15 and the second filter member 16 constituting the filter 11 as described above, so that when the filter unit 12A is pulled up from the molten metal, the filter 11 The fall of foreign matter is suppressed. Further, since the filter unit 12A swivels upstream so as to receive the molten metal M, foreign matter falling from the molten metal is further suppressed. Further, since the filter unit 12A gently cuts the molten metal surface in a state inclined by a predetermined angle θ, the undulation of the molten metal surface is suppressed, and secondary oxidation of the molten metal is suppressed.

  The filter unit 12A pulled up from the molten metal M in this way is replaced with a new filter unit 12A in which a new filter 11 is stretched, and stands by at the standby position. Thereafter, on the basis of the detection signal from the hot water surface sensor 22, the upstream filter unit 12A is installed again in the closed position, while the downstream filter unit 12B currently in use is pulled up to the standby position, and thereafter continuously. The filter units 12A and 12B are alternately installed in the flow path 2 until the end of casting. That is, since the new filter 11 can be replaced without interrupting the supply of the molten metal M to the transport rod 1, the productivity and the molten metal yield are greatly improved. The filter units 12A and 12B may be recycled if necessary.

  FIG. 4 shows a second embodiment of the molten metal cleaning apparatus according to the present invention. The filter used in the second embodiment is the first embodiment described above in that the first filter member 15 with a coarse mesh and the second filter member 16 with a fine mesh are integrated together via a spacer 17. Although it is substantially the same as the filter 11 of the form, it is comprised here as the continuous filter 30 extended long in strip | belt shape.

  As shown in FIG. 4, the cleaning device 10 ′ as the second embodiment includes a filter roll 32 in which the continuous filter 30 is continuously wound around a reel 31, and the filter roll 32 can be rotated. A rotating support shaft (feeding means) 33 to be supported, a turning roller 34 for changing the direction of the continuous filter 30 drawn from the filter roll 32, and a winding for winding the continuous filter 30 changed in direction by the turning roller 34 on a reel 35. And taking means 36. The winding means 36 includes a rotating shaft 37 that is integral with the reel 35 and a driving means 38 that rotationally drives the rotating shaft 37. The driving means 38 is connected to the control means 20 similar to that in the first embodiment by a signal line 39, and the operation of the driving means 38 is controlled by the control means 20. Further, the turning roller 34 is rotatably supported by a lower end portion of an elevating bar 40 that moves up and down by a driving means (not shown), and in use, an arcuate recess formed on the inner bottom surface of the flow path 2 of the transport rod 1. 6 can be installed in a closed position that is partially accommodated in 6.

The rotating support shaft 33 as the feeding means and the rotating shaft 37 as the winding means are arranged above the molten metal surface of the molten metal M in the flow path 2 so that the rotating shaft 37 is located upstream. On the other hand, the turning roller 34 is installed further upstream than the rotating shaft 37. With such an arrangement, the winding side of the continuous filter 30 that is wound around the winding means 36 while bypassing the turning roller 34 is disposed upstream of the feeding side of the continuous filter 30 that is fed from the filter roll 32. Moreover, the winding side and the feeding side are arranged in a state inclined by a predetermined angle θ ′ with respect to the vertical plane. Therefore, the continuous filter 30 is positioned on the winding side so that the first filter member 15 faces the upstream side.
It is to be noted that the hot water level sensor 22 is arranged on the downstream side of the installation area of the continuous filter 30 as in the first embodiment. Further, if desired, a tray 41 and an air blow nozzle 42 may be provided adjacent to the reel 35 of the winding means 36.

Hereinafter, the cleaning method of the molten metal performed using cleaning apparatus 10 'comprised as mentioned above is demonstrated.
At the time of continuous casting, a filter roll 32 formed by winding a new continuous filter 30 around a reel 31 is prepared, and this is attached to a rotation support shaft 33 as a feeding means. At this time, the turning roller 34 is lifted above the flow path 2 by the lifting bar 40, and after the filter roll 32 is attached to the rotation support shaft 33, one end of the continuous filter 30 is pulled out from the filter roll 32. This is bypassed by the turning roller 34 and extended to the winding means 36, and one end thereof is engaged with the reel 35. Next, the turning roller 35 is lowered into the flow path 2 by the lifting bar 40, and the turning roller 35 is installed at the illustrated closed position.

Thereafter, similarly to the first embodiment, the molten metal M is supplied from the melting furnace to one end side of the transport rod 1, and the molten metal M passes through the flow path 2 to the outlet on the other end side of the transport rod 1. It flows as shown by arrow F to the side. Then, when the molten metal surface height of the molten metal M in the flow path 2 reaches the upper limit level h _U that stabilizes the casting quality, the stopper is pulled out from the outlet, and the molten metal is discharged into the mold to start continuous casting. Is done.
During the hot water preparation and during the hot water supply, the molten metal M flows downstream through the continuous filter 30, but the foreign matter contained in the molten metal M is captured by the continuous filter 30 located on the upstream side (winding side). The In this case, since the continuous filter 30 has a double structure in which the first filter member 15 having a coarse mesh and the second filter member 16 having a fine mesh are combined at a slight interval, most of the foreign matter contained in the molten metal. Passes through the first filter member 15, stops at the front surface of the fine second filter member 16, and is captured in the gap S between the filter members 15 and 16. And if the quantity of the foreign material caught by the continuous filter 30 increases, the passage resistance of the molten metal M which passes the continuous filter 30 will rise, and according to this, the molten metal M downstream from the installation area of this continuous filter 30 will increase. The hot water level gradually decreases.

Here, molten metal surface level of the downstream side of the installation area of the continuous filter 30 is monitored by a water level sensor 22, the molten metal surface level is, by a certain value than the lower limit level h _L to stabilize the casting quality When the upper set value h _S or less is reached, the winding means 36 is actuated to rotate the rotating shaft 37 in accordance with a command from the control device 20, and the continuous filter 30 is wound around the reel 35. At this time, the continuous filter 30 located on the take-up side (upstream side) is wound up by a length corresponding to the portion immersed in the molten metal M, whereby the continuous filter located on the feed-out side (downstream side). 30 new parts are updated upstream. On the other hand, the foreign matter captured by the continuous filter 30 is captured by the gap S between the first filter member 15 and the second filter member 16, so that when the immersed portion of the continuous filter 30 is pulled up from the molten metal, The fall of foreign matter from the filter 30 is suppressed. Particularly in the second embodiment, since the continuous filter 30 is pulled up in a state where it is inclined by a predetermined angle θ ′, the fall of foreign matter is further suppressed.

In this way, in the second embodiment, a new filter can be quickly updated upstream by winding a continuous filter by a predetermined length at an appropriate timing, and a plurality of filter units 12 ( Compared to the first embodiment using 12A, 12B) alternately, filter replacement is easy and the overall structure is also simple.
When the tray 41 is provided, the molten metal carried in the air following the continuous filter 30 falls into the tray 41, and when the nozzle 42 is provided, the air is blown from the nozzle 42 by air blowing. The molten metal carried in is rapidly solidified, and as a result, the molten metal M in the flow path 2 is not recontaminated.
The reel 31 as the feeding means may be provided with a brake that generates an appropriate braking force. In this case, the continuous filter 30 is not unintentionally fed from the filter roll 32.

It is sectional drawing which shows typically 1st Embodiment of the cleaning apparatus of the molten metal which concerns on this invention. It is sectional drawing which shows the structure of the filter unit used in 1st Embodiment. It is a top view which shows the structure of the filter unit used in 1st Embodiment. It is sectional drawing which shows typically 2nd Embodiment of the cleaning apparatus of the molten metal which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transport rod 2 Flow path 10, 10 'Molten metal cleaning apparatus 11 Filter 12 (12A, 12B) Filter unit 13 Horizontal axis 14 (14A, 14B) Drive means 15 1st filter member 16 2nd filter member 17 Spacer 18 Holding frame 20 Control means 22 Hot water level sensor 30 Continuous filter 32 Filter roll 31 Reel for feeding (feeding means)
34 Turning roller 35 Reel for take-up 36 Winding means M Molten metal F Flow direction of molten metal

Claims (6)

Molten metal filtration in which a spacer is interposed between the first filter member having a relatively coarse mesh and the second filter member having a finer mesh than the first filter member , and the spacers are integrally combined with an interval corresponding to the plate thickness of the spacer. A filter unit in which a filter is stretched in a holding frame, and at least two of the filter units are arranged at intervals along the flow path through which the molten metal flows, and each filter unit is moved up and down by driving means. The molten metal cleaning apparatus is characterized in that it can be installed in a sluice type in the flow path so that each first filter member faces the upstream side.   2. The molten metal cleaning apparatus according to claim 1, wherein the driving means pivots the filter unit upstream from a horizontal axis coupled to the upper end portion of the filter unit and pulls it up from the molten metal. Molten metal filtration in which a spacer is interposed between the first filter member having a relatively coarse mesh and the second filter member having a finer mesh than the first filter member , and the spacers are integrally combined with an interval corresponding to the plate thickness of the spacer. A sheet roll continuously wound in a roll shape, a feeding means for supporting the sheet roll, a turning roller for changing the direction of the continuous filter fed from the sheet roll, and the direction changed by the turning roller Winding means for winding the continuous filter, the feeding means and the winding means at a position above the surface of the molten metal in the flow path through which the molten metal flows, and the winding means upstream of the feeding means. And the turning roller is arranged at the bottom of the flow path, and the continuous filter is positioned on the winding side by the winding means so that the first filter member faces the upstream side. You Cleaning apparatus of the molten metal, characterized in that.   The molten metal cleaning apparatus according to claim 3, wherein at least the winding side of the continuous filter is inclined upward toward the upstream side.   A method of cleaning molten metal with the cleaning device according to claim 1 or 2, wherein the molten metal surface height is monitored downstream from the installation area of the filter unit, and the molten metal surface height falls below a set value. When this happens, the driving means is operated, and two filter units arranged in the flow direction of the molten metal are alternately installed in the flow path.   A method for cleaning molten metal with the cleaning device according to claim 3 or 4, wherein the height of the molten metal is monitored downstream from the installation area of the continuous filter, and the molten metal surface is below a set value. When it becomes, the cleaning method of the molten metal which operates a winding means and updates the upstream continuous filter.

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