JP5444733B2 - Spray nozzle clogging detection method and detection device for continuous casting machine - Google Patents

Description

  The present invention relates to a spray nozzle clogging detection method and a detection device arranged in a secondary cooling zone of a continuous casting machine used in the steel industry and the like.

  In continuous casting of steel, the molten steel injected into the mold comes into contact with the mold to form a solidified shell on the outer periphery, and then the slab drawn below the mold is a support segment installed below the mold. It is pulled out while being supported by. In this case, a large number of spray nozzles are arranged in the support segment, and the support segment is cooled by cooling water sprayed from the spray nozzles. Cooling in the mold is called “primary cooling”, cooling in the support segment is called “secondary cooling”, and an area where a large number of spray nozzles are arranged is called “secondary cooling zone”.

  By the way, in the slab continuous casting machine, it is necessary to cast slabs of various sizes having different widths. They are arranged side by side at substantially equal intervals in the width direction so that the secondary cooling water is also injected into the end of the slab. However, when casting a narrow slab slab, if secondary cooling water is sprayed in a range corresponding to the maximum width slab slab, the long side surface should be essentially the short side surface of the narrow slab slab. Secondary cooling water to be cooled is jetted, the short side surface and the corners of the short side surface and the long side surface are supercooled, and the surface of the slab is a kind of transverse crack or transverse crack. A corner crack occurs.

  Therefore, in order to prevent overcooling on the short side of the slab, for example, as disclosed in Patent Document 1, the cooling zone is divided into a range of 2 to 3 in the slab width direction, and the maximum width slab casting is performed. When casting pieces, spray from all spray nozzles and stop cooling water from the end side spray nozzles toward the center side spray nozzles according to the width of the cast piece to be cast or amount of cooling water In the case of a slab having a minimum width, a method of cooling only by a spray nozzle at the center of the width is performed.

  However, if casting of cooling water from the spray nozzle on the end side that is not required when casting a narrow slab, scale, mold powder, etc. may occur during casting in the outflow hole of the stopped spray nozzle. There arises a problem that the spray nozzle that has been stuck due to adhesion and intrusion is blocked.

  When the spray nozzle is clogged, the slab surface distribution becomes non-uniform, surface cracks occur in the slab, and the center segregation of the slab deteriorates. It is an extremely important item from the viewpoint of maintaining Conventionally, the inspection of the clogging of the spray nozzle has been carried out by visual inspection of the operator. However, since much labor is required, a method not based on visual observation has been proposed.

  For example, in Patent Document 2, a thermocouple for detecting the temperature of cooling water is provided inside the proximal end of the spray nozzle, the cooling water temperature measured by the thermocouple, the temperature of the cooling water supply base pipe, It is proposed to diagnose spray nozzle clogging using the difference between them, and in Patent Document 3, a pressure detection sensor, a vibration sensor, and respective signal processing devices and storage devices are mounted on a dummy bar. With the movement of the dummy bar, a method for comprehensively detecting clogging of the spray nozzle from the measurement results of both the pressure sensor and the vibration sensor has been proposed.

JP-A-63-290670 JP 2003-170256 A Japanese Patent Laid-Open No. 5-177323

  However, Patent Document 2 and Patent Document 3 have the following problems.

  That is, in patent document 2, it is necessary to attach a thermocouple for every spray nozzle, and in order to diagnose all the spray nozzles of a continuous casting machine, a great number of thermocouples are required, and an installation expense becomes high. There is a problem. In addition, although there is no complete blockage, there is a problem that when the foreign matter is clogged in a part of the outflow hole and the injection shape is changed, there is no change in the water amount or there is little, so that it cannot be detected as an abnormality.

  In Patent Document 3, since the spray pressure of a mist spray that has been frequently used recently is a low pressure, the output of a pressure sensor with a small pressure receiving area is small, and abnormality detection is difficult. In addition, in order to detect a deviation in the spray injection direction and a change in the injection region, it is necessary to detect all pressures in the slab width direction, but for that purpose, it is necessary to arrange a large number of pressure sensors in the width direction, There is a problem that the pressure sensor itself is expensive and the number of installations increases, resulting in extremely high equipment costs. In addition, the vibration sensor may sense vibration other than the spray vibration from the spray nozzle, and there is a problem that it is easily affected by external vibration.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a low-cost and extremely simple mechanism for clogging a spray nozzle installed in a secondary cooling zone of a continuous casting machine. It is another object of the present invention to provide a spray nozzle clogging detection method and a detection device for a continuous casting machine that can be detected with high accuracy.

  A spray nozzle clogging detection method for a continuous casting machine according to a first aspect of the present invention for solving the above-described problem is a method of detecting a plurality of pressure receiving plates whose back surfaces are held by three or more fixed load cells. Arranged in the width direction so as to face the spray nozzles installed in the cooling zone and cover all areas of the spray area from the spray nozzles arranged in the width direction of the slab, the pressure receiving plate in the casting direction Alternatively, while moving in the opposite direction, the pressure of the spray flow injected from the spray nozzle is measured as a load at the load cell via the pressure receiving plate, and the clogging of the spray nozzle is determined based on the change in the load measured at the load cell. It is characterized by detecting.

  The spray nozzle clogging detection method for a continuous casting machine according to the second invention is characterized in that, in the first invention, the pressure receiving plate is installed on a dummy bar.

  A spray nozzle clogging detection method for a continuous casting machine according to a third invention is characterized in that, in the first or second invention, the load cell is capable of detecting both forces in a tensile direction and a compression direction. is there.

  A spray nozzle clogging detection device for a continuous casting machine according to a fourth aspect of the present invention is directed to a spray nozzle disposed in a secondary cooling zone of the continuous casting machine, facing all of the spray nozzles arranged in the slab width direction and facing the spray nozzle. A pressure receiving plate arranged side by side in the width direction so as to cover the region, and three or more load cells per pressure receiving plate holding a surface opposite to the injection surface from the spray nozzle of the pressure receiving plate, A spray nozzle clogging detection device of a continuous casting machine, wherein the load cell is configured to detect a jet flow injected from the spray nozzle toward a pressure receiving plate when the detection device moves between rolls of the continuous casting machine. The pressure is measured as a load, and the clogging of the spray nozzle is detected based on the change in the load measurement value by the load cell.

  A spray nozzle clogging detection device for a continuous casting machine according to a fifth invention is the spray nozzle clogging detection device according to the fourth invention, wherein the spray nozzle clogging detection device is installed in a dummy bar. At the time of drawing out from the load cell, the load cell measures the pressure of the jet flow injected from the spray nozzle toward the pressure receiving plate as a load.

  According to the present invention, since the pressure of the spray flow injected from the spray nozzle is measured as a load by the load cell, when the spray nozzle is blocked, the pressure to the pressure receiving plate changes, and this pressure change is measured by the load cell. This makes it possible to detect clogging of the spray nozzle with high accuracy. The load cell used as a measuring instrument is inexpensive, and it is possible to detect clogging of the spray nozzle with a very simple mechanism at a low cost. Moreover, since the structure is simple, it is excellent in maintainability. Further, the change can be detected with high sensitivity by adjusting the size and arrangement of the pressure receiving plate with respect to the fine pressure spray.

It is a schematic perspective view of the spray nozzle clogging detection device according to the present invention. It is a fragmentary sectional view by the X-X 'arrow of FIG. It is a figure which shows the measured value of the load by a load cell when making the flow volume of water constant and changing the flow volume of air. It is a figure which shows the measured value of the load by a load cell when making the flow volume of air constant and changing the flow volume of water.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic perspective view of a spray nozzle clogging detection device according to the present invention, and FIG. 2 is a partial cross-sectional view taken along the line X-X ′ in FIG. 1.

  As shown in FIGS. 1 and 2, the spray nozzle clogging detection device 1 according to the present invention has a width (W) equal to or wider than the width of a slab (not shown) cast by a continuous casting machine. The rectangular parallelepiped measuring box 2 is used as an outer shell, and all areas of the injection area from the plurality of spray nozzles 7 facing the spray nozzle 7 and arranged in the slab width direction on the long side surface of the measuring box 2 A plurality of pressure receiving plates 4 are attached so as to cover. The pressure receiving plate 4 may have any shape, but in order to detect all the spray injection regions in the width direction of the slab, the plane is rectangular or square, and the adjacent pressure receiving plates 4 are each pressure receiving. The plates 4 are arranged close to each other as long as the vertical movement of the plate 4 is not hindered. The pressure receiving plate 4 is made of metal, synthetic resin, or ceramic.

  The pressure receiving plate 4 is held at its four corners by a load cell 5, and each load cell 5 is held by a load cell support 6 fixed to the measurement box surface plate 3. That is, the load cell 5 is fixed to the measurement box 2 and is configured to measure the pressure received by the pressure receiving plate 4 by the jet flow from the spray nozzle 7 as a load. In this case, in a state where the spray flow from the spray nozzle 7 is not sprayed, adjustment is performed in advance so that an equal load is applied to each load cell 5.

  The positional relationship between the pressure receiving plate 4 and the measurement box surface plate 3 is close to the pressure receiving plate 4 and the measurement box surface plate 3 as long as the pressure receiving plate 4 does not hinder vertical movement, as in the case of the adjacent pressure receiving plates. Are arranged. In FIG. 2, the load cells 5 are arranged at four positions with respect to one pressure receiving plate 4. However, since the pressure receiving plate 4 can be stably held even at three positions, one pressure receiving plate 4 is provided. In contrast, three or more load cells 5 may be arranged.

  The load measurement value by the load cell 5 is stored in a recorder (not shown). The recorder may be disposed inside the measurement box 2 or may be disposed in a continuous casting machine operation room or the like separate from the measurement box 2. In the case where the recorder is arranged at a position different from the measurement box 2, a means such as connecting the two with a cable or connecting them both wirelessly becomes necessary.

  When the pressure receiving plate 4 is installed, if the injection surface from one spray nozzle 7 can be supplemented by one pressure receiving plate 4, one-to-one correspondence is possible, which is preferable as a method for checking nozzle clogging. The spray nozzles of the machine are in a so-called “staggered arrangement”, and it is physically impossible to supplement the spray surface from one spray nozzle 7 with one pressure receiving plate 4 in all secondary cooling zones. However, if one pressure receiving plate 4 is within a range that compensates the ejection surfaces from the two spray nozzles 7, if one spray nozzle is blocked, the load of the load cells 5 arranged on the left and right sides of the pressure receiving plate 4 Therefore, it is preferable to arrange the pressure receiving plate 4 in this way because it is possible to detect the clogging state of the individual spray nozzles 7. However, even when one pressure receiving plate 4 supplements the injection surfaces from three or more spray nozzles 7, it is possible to grasp that a closed spray nozzle exists in the region, so this may be done. . That is, the number of the pressure receiving plates 4 may be appropriately determined according to the width of the slab, the number of spray nozzles 7, the specifications of the spray nozzle 7, and the like.

  The spray nozzle 7 can detect either a water spray nozzle that injects only water or an air mist spray nozzle that injects mist of water and air.

  The continuous casting machine has a casting direction close to vertical on the upper side and a horizontal casting direction on the lower side, and spray nozzles 7 on the lower surface (reference surface side) and upper surface (non-reference surface side) of the continuous casting machine. When the spray nozzle 7 on the lower surface side is inspected, the pressure receiving plate 4 pulls the load cell 5 by gravity, so that the load cell 5 can detect both tension and compression. Preferably there is.

  When the spray nozzle clogging detection device 1 is independently inserted between the rolls of the continuous casting machine to inspect the nozzle clogging, the pressure receiving plates 4 are arranged on both sides of the long side surface of the measuring box 2 to When the upper and lower spray nozzles 7 are inspected at the same time, and when the nozzle clogging detection device 1 is attached to a dummy bar to inspect the nozzle clogging, it is desirable that the thickness (D) of the measuring box 2 is thin. For example, the pressure receiving plate 4 may be disposed on one side of the measurement box 2 and the measurement box 2 may be embedded in a dummy bar. Even when the spray nozzle clogging detection device 1 is attached to the dummy bar, the thickness (D) of the measurement box 2 is set so that the dummy bar is inserted, as in the case where the measurement box 2 is attached to the lower end portion of the upper insertion type dummy bar. If not obstructing, the pressure receiving plates 4 may be arranged on both long side surfaces of the measurement box 2.

  The spray nozzle clogging detection device 1 configured as described above is installed alone or attached to a dummy bar and inserted between rolls of a continuous casting machine, and is moved in the casting direction or the direction opposite to the casting direction. A load cell 5 measures the load caused by the jet flow injected from 7 to the pressure receiving plate 4. When the spray nozzle 7 is blocked, the load measurement value by the load cell 5 changes, and accordingly, clogging of the spray nozzle 7 is detected.

  In the continuous casting machine, as described above, the casting direction gradually shifts from the vertical direction to the horizontal direction. In response to this, the gravity of the pressure receiving plate itself applied to the load cell 5 changes. Further, the flow rate of the jet flow from the spray nozzle 7 changes according to the position of the secondary cooling zone. It is possible to detect all of these data in a computer in advance and compare this data with the measured values to detect nozzle clogging. However, it is extremely complicated, so there is no clogging (such as immediately after replacing the support segment). ) Is stored in the computer, and the measured value is compared with the stored data, so that the nozzle blockage can be easily detected.

  As described above, according to the present invention, since the pressure of the jet flow injected from the spray nozzle 7 is measured as a load by the load cell 5, the pressure to the pressure receiving plate 4 changes when the spray nozzle 7 is blocked. By measuring this pressure change with the load cell 5, it becomes possible to detect clogging of the spray nozzle 7 with high accuracy. Moreover, since all the areas of the spray area from the spray nozzle can be inspected, it is possible to inspect without overlooking various changes in the spray nozzle.

  A spray nozzle clogging detection device similar to the spray nozzle clogging detection device shown in FIG. 1 was produced, and in the laboratory, the pressure on the pressure receiving plate due to the jet flow from the air mist spray nozzle was measured with a load cell. The pressure receiving plate is made of stainless steel, and the size of the pressure receiving plate is 50 mm in length, 100 mm in width, and 3 mm in thickness. In the experiment, the spray nozzle clogging detection device is moved at a speed equivalent to the pulling speed of the dummy bar, and the flow rate of water and air from the air mist spray nozzle is 100% when used in a continuous casting machine. , 50% and 0%, and a simulated occlusion was developed.

  FIG. 3 shows the total load measured by the four load cells when the water flow rate from the air mist spray nozzle is 100% and the air flow rate is reduced to 50% and 0%. The total value of the loads measured by the four load cells when the flow rate of air from the air mist spray nozzle is 100% and the flow rate of water is reduced to 50% and 0% is shown. 3 and 4, the “distance from immediately below the nozzle” on the horizontal axis is the distance between the position immediately below the spray nozzle and the center position of the pressure receiving plate.

  As apparent from FIGS. 3 and 4, when the flow rate of either water or air is 50% or less, the measured value of the load by the load cell decreases, and from the measured value of the load by the load cell, the spray nozzle It was confirmed that clogging was detectable. In this case, clogging can be detected only from the peak height of the measured load, and if the integrated value of the measured load is used as a detection factor, it becomes possible to detect clogging of the spray nozzle more reliably.

DESCRIPTION OF SYMBOLS 1 Spray nozzle clogging detection apparatus 2 Measurement box 3 Measurement box surface plate 4 Pressure receiving plate 5 Load cell 6 Load cell support material 7 Spray nozzle

Claims (4)

Multiple fixed pressure plates with the back surface held by three or more fixed load cells that can detect both tensile and compressive forces are used as spray nozzles installed in the secondary cooling zone of a continuous casting machine. Arranged in the width direction so as to oppose and cover all areas of the spray area from the spray nozzles aligned in the slab width direction, while moving the pressure receiving plate in the casting direction or the opposite direction, The pressure of the jet flow injected from the spray nozzle is measured as a load by a load cell via the pressure receiving plate, and the clogging of the spray nozzle is detected based on a change in the load measured by the load cell. How to detect spray nozzle clogging in a casting machine.   2. The spray nozzle clogging detection method for a continuous casting machine according to claim 1, wherein the pressure receiving plate is installed on a dummy bar. A pressure receiving plate arranged side by side in the width direction so as to cover all areas of the spray area from the spray nozzle facing the spray nozzle installed in the secondary cooling zone of the continuous casting machine and aligned in the slab width direction; A load cell that holds the surface of the pressure receiving plate opposite to the spray surface from the spray nozzle and that can detect both a tensile force and a compressive force per pressure plate. , A spray nozzle clogging detection device of a continuous casting machine,
When the detection device moves between the rolls of the continuous casting machine, the load cell measures the pressure of the jet flow injected from the spray nozzle toward the pressure receiving plate as a load, and changes the load measurement value by the load cell. A spray nozzle clogging detection device for a continuous casting machine, characterized by detecting clogging of a spray nozzle based on the above. The spray nozzle clogging detection device is installed in a dummy bar, and when the dummy bar is inserted into the continuous casting machine or pulled out from the continuous casting machine, the load cell is injected from the spray nozzle toward the pressure receiving plate. 4. The spray nozzle clogging detection device for a continuous casting machine according to claim 3 , wherein the flow pressure is measured as a load.

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