Casting material cooling method and device

Abstract

To provide a cast raw material cooling method and device each of which enables disintegrated high-temperature cast raw material to be surely cooled to a target temperature without increasing dust collection air volume of a dust collector.SOLUTION: A disintegrated cast raw material 2 is placed on a transport device 1 and is cooled while being transported in a cooling hood 3, and air in the cooling hood 3 is sucked by one or a plurality of circulation cooling fans 7 provided in the middle of the cooling hood extending toward a dust collection port from an opening of the cooling hood. The cast raw material is cooled by blowing delivery air to the cast raw material 2 transported in the cooling hood. Preferably, temperature of in-cooling hood air sucked by the circulation cooling fan is measured, and on the basis of the measured value, rotational frequency of a motor is controlled.SELECTED DRAWING: Figure 3b

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for cooling a hot casting material after it has been removed from the flask. [Background technology]

[0002] In continuous casting machines, the mold is opened after casting and the casting material is removed from the mold, but the removed casting material is in a high temperature state of over 500°C. For this reason, the casting material is placed on a transport device and cooled while being transported inside a cooling hood. The cooling hood is a cover formed on the casting transport path to collect dust and cool the material.

[0003] Fig. 1a is an overall view of a conventional cooling hood, and Fig. 1b is its cross-sectional view taken along the line AA. In these figures, 101 denotes a conveying device such as an apron conveyor that conveys casting material 102, and 103 denotes a tunnel-shaped cooling hood that covers the top of conveying device 101. A dust collection port 106 is provided between material inlet 105a, which is the entrance opening 105 of cooling hood 103, and material outlet 105b, which is the exit opening 105. This dust collection port 106 is connected to dust collector 108 via duct 109. Arrow 114 indicates the direction of air flow.

[0004] The dust collector 108 not only draws air from the cooling hood 103 to collect dust, but also cools the casting blank 102 by airflow from the opening toward the dust collection port 106. The faster the cooling air velocity that strikes the casting blank 102, the greater the cooling effect. However, because the cooling hood 103 must enclose the conveying device 101 and the casting blank 102, there are limitations to how much its cross-sectional area can be reduced. Furthermore, the dust collection air volume of the dust collector 108 cannot be increased without limit. Empirically, the effective cooling air velocity for the casting blank 102 is 8 to 15 m / sec. However, achieving a 15 m / sec velocity in practical equipment requires an unrealistic dust collection air volume. Alternatively, extending the length of the cooling hood 103 to ensure sufficient cooling time is considered, but this method is also unrealistic from the perspectives of improving production efficiency and reducing installation space.

[0005] 2a and 2b, the inventors have investigated the possibility of installing an appropriate number of cooling fans 107 in the middle of the cooling hood 103, drawing in outside air and blowing the discharged air at high speed onto the casting material 102 being transported inside the cooling hood 103 through a duct 113. This method improves the cooling rate, but it has been found to pose a problem in that the air flow rate inside the cooling hood 103 increases by the amount of outside air drawn in, which means that the dust collection air volume of the dust collector 108 must be increased.

[0006] Patent Document 1 also discloses that in order to rapidly cool a sand-filled mold to obtain a high-strength mold, the mold is placed in a low-temperature chamber and the air cooled by a refrigerator inside the chamber is circulated using a suction blower. However, this technology in Patent Document 1 is a technique for freezing a mold containing moisture, and cannot be applied to high-temperature casting materials, which have a completely different temperature range. Furthermore, because cooling is performed inside a separate low-temperature chamber, it is not suitable for cooling casting materials that are continuously discharged from a continuous casting machine. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2004-58116 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a method and apparatus for cooling a casting material, which can reliably cool the casting material to a target temperature after demolition without increasing the dust collection air volume of the dust collector. [Means for solving the problem]

[0009] The cooling method of the present invention, which has been made to solve the above problems, is a method of cooling a casting material, in which the casting material after being removed from the flask is placed on a transport device and cooled while being transported inside a cooling hood, and the air inside the cooling hood is sucked in by a plurality of circulating cooling fans provided midway from the opening of the cooling hood to the dust collection port, and the discharged air is blown onto the casting material transported inside the cooling hood, thereby cooling the casting material, wherein the temperature of the air inside the cooling hood sucked in by the circulating cooling fans is measured, The temperature of the casting material, which is correlated with the air temperature, is predicted from the measured air temperature, and the air speed required for cooling is calculated from the temperature difference between the predicted temperature of the casting material and the target temperature after cooling that has been set in advance, and the rotation speed of the circulating cooling fan is controlled by an inverter. It is characterized by the following.

[0010] In addition, The cooling fan forms a spiral airflow toward the dust collection port within the cooling hood. It is preferable.

[0011] The cooling device for casting materials of the present invention, which has been made to solve the above problems, comprises a conveying device for conveying the casting materials within a cooling hood after being removed from the flask, a dust collecting device for sucking air within the cooling hood through a dust collecting port located midway between the inlet and outlet openings of the cooling hood, collecting dust, and discharging the collected dust into the atmosphere, and a plurality of circulating cooling fans, which are located midway between the openings of the cooling hood and the dust collecting port, for sucking air within the cooling hood and blowing the discharged air onto the casting materials from the ceiling of the cooling hood, The circulating cooling fan is equipped with a temperature sensor that measures the temperature of the air being sucked into the cooling hood, a calculation means that predicts the temperature of the casting material, which is correlated with the air temperature, from the measured air temperature, and calculates the air speed required for cooling from the temperature difference between the predicted temperature of the casting material and a preset target temperature after cooling, and an inverter control means that controls the rotation speed of the circulating cooling fan. It is characterized by the following.

[0012] In addition, The cooling fan forms a spiral airflow toward the dust collection port within the cooling hood. It is preferable. [Effects of the Invention]

[0013] In the casting material cooling method and apparatus of the present invention, in addition to the conventional cooling method of cooling the high-temperature casting material while transporting it within the cooling hood, a circulating cooling fan installed midway through the cooling hood blows discharged air onto the casting material. This allows for effective cooling of the high-temperature casting material without increasing the dust collection air volume of the dust collector. Furthermore, since the circulating cooling fan draws air from within the cooling hood and blows the discharged air onto the casting material, the air heated by cooling the casting material returns to the cooling hood. However, because an air flow is constantly formed within the cooling hood from the opening toward the dust collection port, the heated air is not drawn back into the same circulating cooling fan, preventing the air from overheating.

[0014] In addition, in this invention, the temperature of the air inside the cooling hood drawn into the circulating cooling fan is measured, and the rotation speed of the circulating cooling fan is controlled based on the measured temperature, so that the circulating cooling fan can be operated at a rotation speed that corresponds to the progress of cooling of the casting material, thereby reducing power consumption. In this case, if the temperature of the casting material, which is correlated with the air temperature, is predicted from the measured air temperature, and the air speed required for cooling is calculated from the temperature difference between the predicted temperature of the casting material and a predetermined target temperature after cooling, and the rotation speed of the circulating cooling fan is controlled by an inverter, even more accurate cooling can be achieved. [Brief explanation of the drawings]

[0015] [Figure 1a] 1 is an overall view showing a conventional cooling device for a casting material using a cooling hood. [Figure 1b] FIG. 2 is a cross-sectional view taken along the line AA of a conventional cooling device for a casting material using a cooling hood. [Figure 2a] FIG. 1 is an overall view showing a cooling device for casting materials in which a cooling fan is incorporated into a cooling hood. [Figure 2b] This is a B-B cross-sectional view of a cooling device for casting materials in which a cooling fan is incorporated into a cooling hood. [Figure 3a] 1 is an overall view showing an embodiment of the present invention; [Figure 3b] FIG. 1 is a cross-sectional view taken along CC line showing an embodiment of the present invention. [Figure 3c] FIG. 10 is a cross-sectional view showing another embodiment of the present invention. [Figure 4] FIG. 10 is a control system diagram of another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of the present invention will be described below. 3a and 3b are diagrams showing an embodiment of the present invention. In these figures, reference numeral 1 denotes a conveying device for conveying a high-temperature casting material 2 at about 600°C after the molding die is removed. In this embodiment, the conveying device 1 is an apron conveyor, but any other conveying device that can convey high-temperature casting material 2, such as a hanger conveyor, may also be used.

[0017] Reference numeral 3 denotes a cooling hood that covers this conveying device 1. The cooling hood 3 is provided with a dust collection port 6 midway between the material inlet 5a, which is the entrance opening 5, and the material outlet 5b, which is the exit opening 5. This dust collection port 6 is connected to a dust collector 8 via a duct 9, and the dust collector 8 sucks air from inside the cooling hood 3. Therefore, inside the cooling hood 3, there is formed an air flow from the inlet 5a toward the dust collection port 6 and an air flow from the outlet 5b toward the dust collection port 6, and the high-temperature casting material 2 is cooled by coming into contact with these air flows.

[0018] However, as mentioned above, the internal airflow velocity of these cooling hoods 3 is approximately less than 8 m / sec, and empirically, the preferred cooling air velocity is 8 to 15 m / sec. Therefore, this alone is insufficient for cooling. Therefore, in the present invention, one or more circulating cooling fans 7 are installed between the opening of the cooling hood 3 and the dust collection port 6. As shown in Figure 3b, the suction port 10 of the circulating cooling fan 7 is connected to the cooling hood 3 by a duct 11, and it draws air from within the cooling hood 3. The air outlet 12 of the circulating cooling fan 7 is connected to the ceiling of the cooling hood 3 by a duct 13. Therefore, the circulating cooling fan 7 can blow the air from within the cooling hood 3 onto the casting blank 2 at a discharge velocity of, for example, 15 m / sec, thereby cooling it. Note that the arrow 14 indicates the direction of the airflow.

[0019] The air heated by cooling the casting material 2 returns to the cooling hood 3, and repeated circulation of the air could reduce the cooling effect due to localized temperature increases. However, in the present invention, an air flow is constantly formed in the cooling hood 3 from openings such as the inlet 5a and outlet 5b toward the dust collection port 6, so the heated air is not sucked back into the circulating cooling fan 7. In other words, the air in the cooling hood 3 moves in a spiral pattern toward the dust collection port, preventing localized temperature increases and overheating of the air.

[0020] Furthermore, unlike the outside air intake type cooling fan shown in Figure 2b, the circulation cooling fan 7 does not bring outside air into the cooling hood 3. Therefore, the amount of air inside the cooling hood 3 does not increase, and the dust collection air volume of the dust collector 8 can be kept constant. Therefore, even when multiple circulation cooling fans 7 are installed as shown in Figure 3a, there is an advantage that there is no need to increase the dust collection air volume of the dust collector 8.

[0021] Next, another embodiment of the present invention will be described, as shown in Figures 3c and 4. In this embodiment, the suction port 10 of the circulating cooling fan 7 is connected to the cooling hood 3 via a duct 11 to draw in air from inside the cooling hood 3, and the air outlet 12 is connected to the cooling hood 3 via a duct 13 to blow the discharged air onto the casting material 2 for cooling, just like in the previous embodiment.

[0022] In this embodiment, the temperature of the air inside the cooling hood 3 that is drawn into the circulating cooling fan 7 is measured by a temperature sensor TH. In this embodiment, the temperature sensor TH is attached to the duct 11 of a specific circulating cooling fan 7. Based on the measured air temperature, the rotation speed of the circulating cooling fan 7 is controlled by a calculation unit and an inverter control device. The details are as follows.

[0023] During continuous operation, the temperature of the casting material 2 is at its highest when the cooling time is shortest, and the air temperature inside the cooling hood 3, which transports the high-temperature casting material 2, is also at its highest. Furthermore, if the continuous casting machine is temporarily stopped for next-day disassembly, the cooling time is extended, causing the temperature of the casting material 2 to drop, and the air temperature inside the cooling hood 3 also drops. Specifically, by measuring the air temperature inside the cooling hood 3 during transport of the casting material 2, which is the highest temperature during continuous operation, and the air temperature inside the cooling hood 3 when the casting material 2 has cooled, in stages, a calibration curve is drawn that shows the proportional relationship between the air temperature inside the cooling hood 3 and the temperature of the casting material 2. Using an equation derived from this calibration curve, the temperature of the casting material 2 can be estimated from the measured air temperature inside the cooling hood 3. In this way, the temperature of the casting material 2 at the installation position of the temperature sensor TH is estimated, and the temperature difference from the predetermined cooling target temperature is calculated.

[0024] In the field of heat transfer engineering, the temperature change of an object when it is cooled by air is expressed as θ=θf+(θ0-θf)e ∧ It is known that this can be expressed by the formula (-mt). Here, θ is the temperature of the object, θf is the air temperature, θ0 is the initial temperature of the object, and t is time. The value of m is expressed by the formula m=αs / cγV, where α is the overall heat transfer coefficient, s is the surface area of ​​the object, c is the specific heat of the object, γ is the specific gravity of the object, and V is the volume of the object. The overall heat transfer coefficient α is α=6.14·ω ∧ It is expressed as (0·78), where ω is the wind speed. In other words, there is a correlation between the wind speed ω and the cooling rate, and by inputting the surface area s, specific heat c, specific gravity γ, volume surface area of ​​the casting material 102, where c is the specific heat of the object, etc., it is possible to calculate the wind speed ω required to cool the measured temperature of the casting material 2 to the cooling target temperature within a specified time.

[0025] In order to achieve the calculated required air velocity ω, the inverter control device controls the rotation speed of the circulating cooling fans 7. By optimizing the cooling air velocity of the casting material 2 by each circulating cooling fan 7 in this way, it is possible to reduce power consumption.

[0026] The advantages of the present invention described above can be summarized as follows: (1) The casting material can be cooled to the target temperature without having to worry about shortening the time cycle of the molding line of the casting equipment to improve production efficiency or shortening the material transport / cooling conveyor of the post-processing equipment due to installation space restrictions. (2) There is no need to increase the dust collection air volume more than necessary to cool the casting material. (3) Due to ventilation caused by dust collection, the air inside the cooling hood that cools the casting material does not circulate through the same circulating cooling fan, but flows in a spiral pattern inside the cooling hood toward the dust collection port, which prevents the circulating air from rising in temperature. (4) By controlling the rotation speed of the circulating cooling fan using an inverter, the wind speed of the discharged air hitting the casting material can be optimized, thereby reducing power consumption. [Explanation of symbols]

[0027] 1. Conveyor device 2 Casting materials 3 Cooling Hood 5 Opening 5a Material entrance 5b Material outlet 6 Dust collection port 7 Circulating Cooling Fan 8 Dust collector 9 Duct 10 Suction port 11 Duct 12 Air outlet 13 Duct 14 Air flow direction 102 Casting materials 103 Cooling Hood 105 Opening 106 Dust collection port 107 Circulating cooling fan 108 Dust collector 109 Duct 113 Duct 114 Air flow direction TH temperature sensor

Claims

1. A method for cooling a casting material, comprising: placing a casting material after removal from a flask on a transport device, transporting the casting material in a cooling hood while cooling the casting material; and sucking air from inside the cooling hood with a plurality of circulating cooling fans provided midway between an opening of the cooling hood and a dust collection port, and blowing the discharged air onto the casting material transported in the cooling hood, the method comprising: A method for cooling a casting material, comprising the steps of: measuring the temperature of the air in the cooling hood drawn in by the circulating cooling fan; predicting the temperature of the casting material, which is correlated with the air temperature, from the measured air temperature; calculating the air speed required for cooling from the temperature difference between the predicted temperature of the casting material and a preset target temperature after cooling; and inverter-controlling the rotation speed of the circulating cooling fan.

2. A method for cooling casting material as described in claim 1, characterized in that the cooling fan forms a spiral air flow within the cooling hood toward the dust collection port.

3. The cooling hood has a conveying device for conveying the casting materials after being stripped from the flask within the cooling hood, a dust collecting device for sucking air from within the cooling hood through a dust collecting port located midway between the inlet and outlet openings of the cooling hood, collecting dust, and discharging the collected dust into the atmosphere, and a plurality of circulating cooling fans located midway between the openings of the cooling hood and the dust collecting port, for sucking air from within the cooling hood and blowing the discharged air onto the casting materials from the ceiling of the cooling hood, The cooling device for casting materials is characterized in that the circulating cooling fan comprises a temperature sensor that measures the temperature of the air drawn into the cooling hood, a calculation means that predicts the temperature of the casting material, which is correlated with the air temperature, from the measured air temperature, and calculates the air speed required for cooling from the temperature difference between the predicted temperature of the casting material and a preset target temperature after cooling, and an inverter control means that controls the rotation speed of the circulating cooling fan.

4. A cooling device for casting materials as described in Claim 3, characterized in that the cooling fan forms a spiral air flow within the cooling hood toward the dust collection port.

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