JP2024064040A - Antenna cover and microwave level meter equipped with said antenna cover - Google Patents

Abstract

[Problem] To reduce the maintenance burden of microwave level gauges in blast furnaces, etc. [Solution] An antenna cover is attached so as to surround the periphery of the tip portion provided at the tip of a waveguide and to be rotatable around the periphery of the tip portion, and is formed in a cylindrical shape with at least one end open. The antenna cover is characterized by having a predetermined heat resistance and being made of a material that transmits microwaves. [Selected Figure] Figure 1

Description

The present invention relates to an antenna cover that prevents the reflector from becoming dirty due to dust or other particles, and a microwave level meter equipped with the antenna cover.

The invention described in Patent Document 1 discloses a technology that eliminates the obstruction of work vehicles and workers in a microwave distance meter that is installed on the floor above the torpedo car, molten iron ladle, and slag ladle in a blast furnace, reduces the amount of disassembly and reassembly work required during maintenance, and improves detection accuracy.

JP 2007-178207 A

However, in the invention described in Patent Document 1, the reflector plate of the microwave distance meter is located above the torpedo car, molten iron ladle, and slag ladle in the blast furnace, so dust and other contaminants are likely to adhere to the reflector plate. In order to remove the contaminants, it is necessary to remove not only the reflector plate with the contaminants attached, but also the entire microwave distance meter and the waveguide connected to the microwave distance meter from inside the castbed, which imposes a large maintenance burden on the microwave distance meter.

The present invention was made in consideration of these circumstances, and the objective of the present invention is to reduce the maintenance burden of microwave level meters in blast furnaces and the like.

To solve this problem, the invention described in claim 1 is an antenna cover that is attached to the tip of a waveguide so as to surround the tip and to be rotatable around the tip, the antenna cover being formed in a cylindrical shape with at least one end open, the antenna cover having a predetermined heat resistance, and being made of a material that is transparent to microwaves.

The invention described in claim 2 is a microwave level meter used to detect the amount of pig iron in a torpedo car or molten iron ladle located below a cast floor in a blast furnace, or the amount of slag in a slag ladle, comprising: a microwave control unit disposed inside or on the underside of the cast floor and controlling the transmission of microwaves and the reception of reflected waves of the microwaves; a waveguide disposed inside or on the underside of the cast floor and transmitting the microwaves; and an antenna unit connected to the microwave control unit and transmitting microwaves and receiving reflected waves of the microwaves under the control of the microwave control unit, the waveguide having a reflector disposed at an angle at the tip inside the waveguide, The microwaves transmitted from the antenna unit under the control of the microwave control unit are guided by the waveguide and radiated toward the liquid surface of the torpedo car or the molten iron ladle, or the slag ladle by reflection from the reflector, and the microwaves reflected by the radiation are guided by the waveguide to the microwave control unit by reflection from the reflector, thereby detecting the amount of the received molten iron in the torpedo car or the molten iron ladle located below the cast floor in the blast furnace, or the amount of the slag in the slag ladle, and the antenna cover described in claim 1 is attached to surround the periphery of the tip.

The invention described in claim 3 is characterized in that the waveguide is provided with a cover that can be rotated in the vertical direction so that it can be covered and opened by rotating it, and is configured so that when the cover is rotated downward, it covers the upper part of the antenna cover, and when the cover is rotated upward, it opens the upper part of the antenna cover.

According to the inventions of claims 1 and 2, the antenna cover is rotatably attached around the tip of the waveguide, which prevents dust and other contaminants from adhering to the reflector at the tip. Even if dust and other contaminants adhere to the antenna cover, the antenna cover can be accessed from above the casting bed and rotated at a predetermined angle to position the clean side of the antenna cover downward and face the liquid surface, thereby maintaining optimal detection of the amount of pig iron received without removing the adhering contaminants. In addition, since the surface with the contaminants is positioned upward by rotating the antenna cover, the antenna cover can be easily accessed from above the casting bed to remove the contaminants, and an antenna cover and microwave level meter that reduce the maintenance burden of the microwave level meter can be provided.

According to the invention of claim 3, a cover that prevents the accumulation of dust and the like on the antenna cover is further attached so that it can rotate. By accessing the cover from the top of the casting floor and rotating it upward to release it, dust and the like that has accumulated on the antenna cover can be easily removed. This makes it possible to provide a microwave level meter that not only reduces the maintenance burden on the antenna cover, but also reduces the maintenance burden on the antenna cover.

1 is a schematic diagram showing an overall structure in which an antenna cover according to an embodiment of the present invention is attached to a microwave level meter; 1 is a schematic diagram showing a structure of an antenna cover according to an embodiment of the present invention; 1A to 1C are diagrams showing one mode for rotating the antenna cover according to an embodiment of the present invention. 4A and 4B are diagrams showing a covering that prevents dust and the like from adhering to the upper surface of the antenna cover according to the embodiment of the present invention. 13A to 13C are diagrams showing an example in which an antenna cover according to an embodiment of the present invention is attached to a waveguide of another shape.

The embodiment of the present invention will be described with reference to Figures 1 to 5.

Figure 1 is a schematic diagram showing the overall structure of an antenna cover 4 according to an embodiment of the present invention attached to a microwave level meter 1.

The microwave level meter 1 is, for example, provided inside the casting floor 41 and includes a microwave control unit 2 that controls the transmission of microwaves and the reception of reflected microwaves, a waveguide 3 that is provided inside the casting floor 41 and transmits microwaves that are received and transmitted under the control of the microwave control unit 2, an antenna cover 4 that is rotatably attached so as to surround the tip 3a of the waveguide 3, and an antenna unit 7 that is connected to the microwave control unit 2 provided at the end of the waveguide 3.

The microwave control unit 2 controls the transmission of microwaves and the reception of microwaves reflected by the liquid surface 43, measures the distance from the antenna unit 7 to the liquid surface 43 of the torpedo car 42 based on the time required from the transmission of microwaves to the reception of the reflected microwaves, and detects the amount of pig iron received by the torpedo car 42 based on the measured distance.

The waveguide 3 is generally a hollow metal tube through which microwaves are transmitted. The waveguide 3 has a reflector 5 arranged at an angle inside the tip 3a at its tip, and a notch 6 having a size necessary and sufficient for the irradiation area of the microwaves radiated toward the liquid surface 43 by reflection by the reflector 5. Specifically, the tip 3a has the reflector 5 so as to incline from the top to the bottom from the direction of the microwave control unit 2 toward the tip 3a. The waveguide 3 transmits microwaves transmitted from the antenna unit 7 under the control of the microwave control unit 2, and reflects them toward the liquid surface 43 of the torpedo car 42 through the notch 6 by the reflector 5. The waveguide 3 also reflects the microwaves reflected by the liquid surface 43 toward the antenna unit 7 through the notch 6 by the reflector 5, and transmits them so that they are received by the antenna unit 7 by the microwave control unit 2. The waveguide 3 may be a single waveguide or may be constructed by connecting multiple waveguides.

Here, the structure of the antenna cover will be explained using Figure 2. This is a schematic diagram showing the structure of the antenna cover according to an embodiment of the present invention.

The antenna cover 4 has a cylindrical main body 4a and an open surface 4b where both ends of the main body 4a are open. Note that it is sufficient that at least one end of the main body 4a of the antenna cover 4 is open, so that the antenna cover 4 has an open surface 4b where one end of the main body 4a is open, and a closed surface where the other end of the main body 4a is closed.

The antenna cover 4 is rotatably attached so as to surround the tip 3a, covering the entire tip 3a, and can rotate clockwise or counterclockwise around the axis A shown in FIG. 2.

However, the area around the tip 3a where the antenna cover 4 is attached becomes very hot, so a certain level of heat resistance is required. Also, in order to detect the amount of pig iron in the torpedo car 42 using microwaves, the antenna cover 4 needs to be transparent to microwaves.

First, the heat resistance of the antenna cover 4 will be described. The antenna cover 4 is attached to surround the tip 3a, which is equipped with a reflector 5 arranged at an angle at the tip inside the waveguide 3 and is installed in a blast furnace or the like, and is made of a material with a certain heat resistance. In general, the molten iron supplied to the torpedo car 42 and the area around the tip 3a located above it become very hot. Therefore, it is desirable for the antenna cover 4 to have a certain heat resistance that can withstand the high temperatures of the molten iron and the area around the tip 3a.

Next, we will explain the transparency of the antenna cover 4. The antenna cover 4 is made of a material that has the property of transmitting microwaves and reflected microwaves.

Thus, the antenna cover 4 may be made of any material that has the above-mentioned heat resistance and microwave transparency.

Here, an example of a method for rotating the antenna cover 4 will be described as shown in FIG. 3. FIG. 3 is a diagram showing one mode for rotating the antenna cover according to an embodiment of the present invention.

As described above, the temperature around the tip 3a where the antenna cover 4 is attached is high, so there is a risk of getting burned if the hands and feet touch the antenna cover 4 or the casting floor 41 when rotating the antenna cover 4. Therefore, as shown in FIG. 3, a belt 11 may be used to rotate the antenna cover 4. The belt 11 is preferably made of a heat-resistant material. The antenna cover 4 can be rotated manually while wearing heat-resistant gloves, but it is safer to rotate the antenna cover 4 using the belt 11. Specifically, as shown in FIG. 3, the belt 11 is passed through the lower part of the antenna cover 4, and both ends of the belt 11 are held upward while the belt 11 and the antenna cover 4 are in close contact with each other. Then, the antenna cover 4 can be rotated by lifting one end of the belt 11 further upward.

Next, we will explain the surrounding environment where the antenna cover is attached. Not only does the area around the tip 3a where the antenna cover 4 is attached become hot, but dust also blows upward from below. If dust adheres to the reflector 5 or notch 6 where the microwaves are irradiated, the microwaves will be attenuated and scattered, preventing them from being reflected to the amount of pig iron being received. Therefore, the area around the tip 3a needs to be protected from not only heat but also dust, and it needs to be removed.

Therefore, using Figure 4, we will explain a structure that can prevent dust and other contaminants from accumulating on the top surface of the antenna cover 4. Figure 4 is a diagram showing a cover that prevents dust and other contaminants from accumulating on the top surface of the antenna cover in accordance with an embodiment of the present invention.

As shown in FIG. 4, the waveguide 3 is provided with a cover 21 that can be rotated in the vertical direction so that it can be covered and opened by rotating it. When the cover 21 is rotated downward, it covers the upper part of the antenna cover 4, and when the cover 21 is rotated upward, it opens the upper part of the antenna cover 4. The cover 21 is rotated in the vertical direction using a lever 22 provided on the waveguide 3.

When the covering body 21 is rotated downward to cover the upper part of the antenna cover 4, the covering body 21 and the antenna cover 4 may come into contact with each other. As described below, in addition to visual inspection, it can be determined that the antenna cover 4 has become dirty when the measurement of the amount of pig iron received by the microwave control unit 2 is affected. In this way, when removing the dirt that has adhered to the antenna cover 4, the covering body 21 is rotated upward to open the upper part of the antenna cover 4, and the dirt can be removed from the antenna cover 4 by accessing it through an opening (not shown) in the casting floor 41. After removing the dirt from the antenna cover 4, the procedure is reversed to cover the upper part of the antenna cover 4 with the covering body 21 rotated downward.

Furthermore, we will explain the maintenance flow when dust or other dirt adheres to the antenna cover 4.

In general, due to the nature of the dust in the casting bed 41, dust tends to adhere to the bottom of the antenna cover 4. Therefore, by rotating the antenna cover 4, the clean surface of the main body 4a can be positioned downward and facing the liquid surface 43, making it easy to perform maintenance on the antenna cover 4.

Whether or not dust or other contaminants are attached to the antenna cover 4 can be confirmed by visual inspection, for example, or it can be determined that the antenna cover 4 is contaminated when the microwave control unit 2 receives microwaves reflected by the liquid surface 43 at an angle different from normal, or when the amount of pig iron detected by the microwave control unit 2 based on the time required to transmit and receive microwaves is an abnormal value.

In order to remove the dirt and detect the amount of pig iron received appropriately, the antenna cover 4 is rotated around the axis A of the waveguide 3 so that the clean surface of the main body 4a, which is not contaminated, is positioned downward and the clean surface faces the liquid surface 43. To rotate the antenna cover 4, for example, an opening (not shown) located at the top of the casting bed can be opened to access and rotate the antenna cover 4. Specifically, the antenna cover 4 is rotated until the clean surface of the main body 4a faces the liquid surface 43. To rotate the antenna cover 4 from the contaminated surface to the clean surface of the main body 4a, the antenna cover 4 is rotated clockwise or counterclockwise, for example, 90 degrees. As long as the adhesion of dirt to the antenna cover 4 does not affect the detection of the amount of pig iron received by the microwave control unit 2, the angle at which the antenna cover 4 is rotated is not limited to the above angle.

If it is found that dirt has adhered to the antenna cover 4 again after rotating the antenna cover 4, the antenna cover 4 may be rotated in the same direction as described above. If it is rotated 90 degrees clockwise the first time, it is rotated 90 degrees clockwise the second time. If it is rotated 90 degrees counterclockwise the first time, it is rotated 90 degrees counterclockwise the second time. If the antenna cover 4 is rotated twice in the same direction by 90 degrees each time, the surface of the main body 4a that was originally facing the liquid surface 43 faces upward. At this time, an opening (not shown) provided above the casting bed 41 can be opened to access the antenna cover 4 and remove the dirt from the main body 4a on which dirt such as dust is adhered. As a method for removing dirt such as dust adhered to the main body 4a, for example, an air blow can be used, but is not limited to this.

If dirt accumulates on the antenna cover 4 as the microwave level meter 1 is used, the dirt can be removed by repeating these procedures. This not only reduces the maintenance burden on the microwave level meter 1, but also enables the microwave level meter 1 to maintain its ability to accurately detect the amount of pig iron received.

Returning to FIG. 1, the antenna unit 7 is connected to the microwave control unit 2, and transmits microwaves and receives reflected microwaves under the control of the microwave control unit 2. Note that in FIG. 1, the shape of the antenna unit 7 is a horn antenna, but it may be, for example, a parabolic antenna or another shape.

The support part 8 is a member that aims to reduce the burden on the waveguide 3 and the mounting members such as screws used in the waveguide 3, and the support part 8 can support the waveguide 3 by fixing the waveguide 3.

The main body support part 9 also supports the container in which the microwave control part 2 is stored, similar to the function of the support part 8.

The cast floor 41 is a work floor where molten iron runners and the like are installed, and the microwave level meter 1 shown in FIG. 1 is disposed inside the cast floor 41, but may also be disposed on the underside of the cast floor 41.

Molten iron 44 is supplied to the torpedo car 42 from a molten iron ladle (not shown) via a tilting ladle 45. The liquid level 43 refers to the surface of the molten iron 44. Although a torpedo car 42 is shown in FIG. 1, a receiving vessel such as a molten iron ladle or a slag ladle for detecting the amount of slag may be used instead of the torpedo car 42.

The operation will be explained below. In this embodiment, the antenna cover 4 is made of a material that is heat resistant and microwave transparent, and is suitable for attachment to equipment installed in high-temperature, dusty environments such as blast furnaces and coke ovens, for example, microwave level meter 1.

In this embodiment, the microwaves transmitted by the antenna unit 7 under the control of the microwave control unit 2 are transmitted through the waveguide 3 and radiated by the reflector 5 provided at the tip 3a through the notch 6 toward the liquid surface 43 of the torpedo car 42. The microwaves reflected by the liquid surface 43 of the torpedo car 42 are reflected toward the antenna unit 7 by the notch 6 and reflector 5 provided at the tip 3a located above the torpedo car 42, transmitted through the waveguide 3, and received by the antenna unit 7 under the control of the microwave control unit 2. The microwave control unit 2 measures the distance from the antenna unit 7 to the liquid surface 43 based on the time required from the transmission of the microwaves to the reception of the reflected microwaves, and detects the amount of pig iron based on the measured distance.

The microwave control unit 2 can detect not only the amount of iron in the torpedo car 42, but also the amount of iron in the molten iron ladle and the amount of slag in the slag ladle by using the same means as described above.

In this embodiment, when the microwave level meter 1 is disposed inside the casting floor, the antenna cover 4 can be accessed from above the casting floor 41. Therefore, if it is discovered that the antenna cover 4 is dirty, the antenna cover 4 can be easily rotated according to the above procedure to bring the clean surface of the main body 4a into opposition with the liquid surface 43, thereby eliminating any abnormalities in the detection of numerical values by the microwave control unit 2.

In this embodiment, if the microwave level meter 1 is installed inside the casting floor, it is necessary to remove the microwave level meter 1 from inside the casting floor 41 in order to remove dirt adhering to the reflector 5, which is a large burden. However, by rotatably attaching the antenna cover 4 to the tip 3a, the burden of maintaining the microwave level meter 1 can be reduced.

In this embodiment, the antenna cover 4 is rotatably attached so as to surround the periphery of the tip 3a. Since the antenna cover 4 is made of a material that transmits microwaves, the microwaves pass through the antenna cover 4 through the cutout 6 and are radiated toward the liquid surface 43 of the torpedo car 42, without affecting the radiation of the microwaves and the transmission of the reflected microwaves to the waveguide 3. In addition, the reflector 5 provided at the tip 3a can be prevented from being affected by dust or other contaminants and radiant heat. Even if the antenna cover 4 is contaminated, the antenna cover 4 can be rotated at a specified angle to face the clean surface of the main body 4a against the liquid surface 43, thereby maintaining proper detection of the amount of pig iron received by the microwave control unit 2.

In this embodiment, the use of the antenna cover 4 can protect the microwave level meter 1 from dust and other particles and from high temperatures, making it possible to extend the maintenance interval for the microwave level meter 1 and to easily maintain the microwave level meter 1.

In this embodiment, when the microwave level meter 1 is installed inside or on the underside of the casting floor 41, the antenna cover 4 can be accessed from the top of the casting floor 41 and operated. Specifically, the antenna cover 4 is accessed from the top of the casting floor 41, and the antenna cover 4 is rotated according to the above procedure to make the clean surface of the main body 4a face the liquid surface 43. When the dirty surface of the main body 4a is positioned upward by rotating the antenna cover 4, the dirt adhering to the main body 4a can be removed by accessing it from an opening (not shown) of the casting floor 41, thereby reducing the maintenance burden of the microwave level meter 1.

Using belt 11 to rotate antenna cover 4 during maintenance of antenna cover 4 makes maintenance safer.

Furthermore, by covering the upper part of the antenna cover 4 with the covering body 21 rotated downward, it is possible to prevent the accumulation of dirt such as dust on the antenna cover 4. Also, since the covering body 21 is rotatably attached, dirt such as dust adhering to the antenna cover 4 can be removed by accessing it from the upper part of the casting floor 41 and rotating the covering body 21 upward to release it, thereby reducing the maintenance burden not only of the microwave level meter 1 but also of the antenna cover 4.

It goes without saying that the above-mentioned embodiments are merely examples of the present invention, and do not mean that the present invention is limited to only the above-mentioned embodiments.

For example, the antenna cover 4 is formed in a cylindrical shape, but is not limited to a cylindrical shape as long as it can be rotated around the tip portion 3a and can be attached so as to surround the tip of the tip portion 3a.

In addition, since the waveguide 3 is a hollow metal tube through which microwaves can be guided, it is not limited to a cylindrical shape as shown in FIG. 2, but may be a rectangular tube-shaped waveguide 31 as shown in FIG. 5, or may have other shapes.

In addition, in the above, microwaves were used as an example, but radio waves such as millimeter waves can also be used as long as they can detect the amount of pig iron received.

Reference Signs List 1: Microwave level meter 2: Microwave control section 3, 31: Waveguide 3a: Tip section 4: Antenna cover 4a: Main body section 4b: Open surface 5: Reflector 6: Notch section 7: Antenna section 8: Support section 9: Main body support section 11: Belt 21: Covering body 22: Lever 41: Casting bed 42: Torpedo car 43: Liquid surface 44: Molten iron 45: Tilting trough A: Axis

Claims (3)

An antenna cover that is attached so as to surround a tip portion provided at the tip of a waveguide and to be rotatable around the tip portion,
The antenna cover is formed in a cylindrical shape with at least one end open,
The antenna cover is characterized in that the antenna cover is made of a material having a predetermined heat resistance and transmitting microwaves. A microwave level meter used to detect the amount of molten iron in a torpedo car or molten iron ladle located below a cast floor in a blast furnace, or the amount of slag in a slag ladle,
A microwave control unit is disposed inside or under the casting bed and controls the transmission of microwaves and the reception of reflected microwaves;
A waveguide that is disposed inside or under the casting bed and transmits the microwaves;
an antenna unit connected to the microwave control unit and configured to transmit microwaves and receive reflected waves of the microwaves under the control of the microwave control unit;
The waveguide has a reflector disposed obliquely at an inner tip of the waveguide,
The microwaves transmitted from the antenna unit under the control of the microwave control unit are guided by the waveguide and radiated toward the liquid surface of the torpedo car, the molten iron ladle, or the slag ladle by reflection from the reflector, and the microwaves reflected by the radiation are guided by the waveguide to the microwave control unit by reflection from the reflector, thereby detecting the amount of the received iron in the torpedo car or the molten iron ladle, or the amount of the slag in the slag ladle, which are located below the cast floor in the blast furnace;
A microwave level meter, comprising: an antenna cover according to claim 1 attached to surround the periphery of the tip portion. the waveguide is provided with a cover that can be rotated in an up-down direction so that the cover can be covered and opened by rotating the cover,
The cover is rotated downward to cover the upper part of the antenna cover,
The microwave level meter according to claim 2, characterized in that the top of the antenna cover is opened when the covering is rotated upward.

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