JP2570886B2 - Furnace level meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention measures the level of a raw material such as a slag level, a molten steel level, a raw material level in a furnace in a converter, a blast furnace, a smelting reduction furnace, and the like using a microwave. The present invention relates to an in-furnace level meter and an antenna used for the in-furnace level meter.

[Prior Art] FIG. 31 is an explanatory view showing a conventional in-furnace level meter. In the figure, 1 is a smelting reduction furnace, 2 is a microwave radar, 3
Is a transmitting antenna, 4 is a receiving antenna, 5 is a waveguide, 6 is slag, 7 is molten steel, 8 is a lance, 9 is a hood, and the transmitting and receiving antennas 3 and 4 installed in the furnace use horn antennas. Are connected to a microwave radar 2 installed on the top of the smelting reduction furnace 1 by a waveguide 5.

The distance between the slag 6 and the slag surface in the furnace is determined by the electromagnetic wave transmitted by the microwave radar 2 via the waveguide 5 and the transmission antenna 3 from the surface of the slag 6, causing the reception antenna 4 and the waveguide 5 to move. The received microwave was then processed by signal processing and measured.

There are various types of microwave radars that process the microwaves.

For example, as an FM-CW microwave radar system,
As shown in Japanese Patent No. 21584, the frequency of a microcontinuous wave near 10 GHz is FM-modulated and transmitted from the antenna to the level plane, and the beat frequency obtained by mixing this transmission signal and the reflected wave from the level plane is obtained. There is a method of counting and measuring the distance to the level surface. In this method, the distance can be measured by matching the required propagation time for the microwave to and fro from the antenna to the level plane with the beat frequency.

Also, as a pulse-modulated microwave radar system, the time required for radio wave propagation to transmit a microwave with a frequency of about 10 to 20 GHz with pulse modulation and receive a reflected wave from the level surface, as in a normal aircraft radar. There is a method of measuring the distance by measuring the distance in proportion to the distance to the level surface.

[Problem to be Solved by the Invention] In the in-furnace level meter using the conventional microwave radar as described above, the transmitting antenna 3 and the receiving antenna 4 are fixed to the furnace top of the smelting reduction furnace 1 or a specific position in the furnace. Therefore, the following problems have occurred with respect to the fluctuation of the slag surface of the slag 6 in the furnace.

For example, when these antennas 3 and 4 are installed near the furnace top, the slag surface of the slag 6 in the furnace decreases,
When the distance between 4 and the slag surface increases, the lance 8
And slag level position may not be able to be measured accurately due to the influence of unnecessary reflection signals from the furnace mouth and the furnace wall.

Also, when these antennas 3 and 4 are installed on the back side of the furnace, the slag surface of the slag 6 in the furnace rises, and when the distance from the slag surface becomes short, the slag scattered on these antennas 3 and 4 Metal, dust, etc. adhere, causing signal attenuation and antenna 3,
In some cases, the slag level position could not be measured accurately due to the blockage of 4 and the like.

The present invention has been made in order to solve such a problem. Even if the slag surface of the slag in the furnace fluctuates, the slag level position can be accurately and continuously measured, and the atmosphere in which the furnace becomes extremely hot can be obtained. It is an object of the present invention to obtain an in-furnace level meter and an antenna used for the in-furnace level meter which can also be used in the above.

[Means for Solving the Problems] A furnace level meter according to the present invention has a transmitting antenna and a receiving antenna inserted into a furnace, outputs a microwave signal to the transmitting antenna, and outputs a slag in the furnace. A microwave radar that calculates the distance between these antennas and the slag surface from the microwave signals reflected by the surface and received by the receiving antenna and outputs the result as a radar measurement signal, and the transmitting and receiving antennas inserted into the furnace An antenna elevating device that raises and lowers the antenna, an antenna position measuring device that measures the antenna position and outputs an antenna position signal, and a slag level position in the furnace from the radar measurement value signal of the microwave radar and the antenna position signal of the antenna position measuring device Is calculated, and the slag level position in the furnace is compared with a predetermined predetermined value or an upper limit set value and a lower limit set value. And a signal processing unit for calculating the elevation amount and outputting the antenna elevation amount as an antenna elevation control signal to the antenna elevation device.

The transmitting and receiving antennas are entirely water-cooled including a metal inner tube having a diameter-enlarging portion whose inner side functions as a waveguide, and the inner side functions as a horn antenna at the end, and a metal outer tube surrounding the inner tube. A horn antenna that joins the distal end of the enlarged diameter portion of the inner tube and the distal end of the outer tube, interposes a partition member almost all between the inner tube and the outer tube, and communicates at the distal ends of both tubes. Are formed, and a cooling water supply port and a drain port are provided at the base end side of these cooling water paths.

Further, a gas purge port through which a purge gas flows may be provided on the base end side of the inner pipe.

Further, the transmitting and receiving antennas function as waveguides on the entire inner side, and first and second metal inner tubes each having a large-diameter portion functioning as a horn antenna at the tip, and first and second inner tubes. A water-cooled horn antenna comprising a metal outer tube surrounding a tube, wherein the enlarged portion at the tip of the first and second inner tubes and the tip of the outer tube are joined, and a gap between the inner tube and the outer tube is formed. A partition member is interposed substantially all over, two cooling water passages communicating with each other at the distal ends of these two pipes are formed, and a cooling water supply port and a water discharge port are provided at the base end side of these cooling water passages. May be.

Further, a gas purge port through which a purge gas flows may be provided at the base ends of the first and second inner pipes.

Furthermore, the transmitting and receiving antenna may be a water-cooled parabolic antenna comprising a primary radiator of a water-cooled structure and a reflector of a water-cooled structure having a parabolic surface facing an opening surface of the primary radiator. The primary radiator is composed of a waveguide and a feeder having a water cooling structure of a double tube or triple tube structure.

The reflector has a parabolic curved surface facing the opening surface of the primary radiator, a back plate arranged on the back of the reflector, and a partition interposed between the reflector and the back plate. The cooling water passage may be formed by joining the outer periphery of the reflection plate and the back plate, and the cooling water supply port and the drain port may be provided on the back plate. The inner surfaces of the waveguide and feeder of the primary radiator and the parabolic curved surface of the reflector may be gas-purged.

[Operation] In the present invention, a radar processing signal of the distance between the slag surface in the furnace and the antenna measured by the microwave radar and the antenna position signal of the antenna position measured by the antenna position measuring device are processed by a signal processing circuit. The signal processing circuit calculates a slag level position in the furnace from these two signals, compares the slag level position with a predetermined set value, calculates an antenna elevation amount, and calculates the antenna elevation amount. An antenna elevating control signal is input to the antenna elevating device, and the antenna elevating device raises and lowers the antenna according to the antenna elevating control signal, and controls the antenna elevating so that the distance between the antenna and the slag surface is always maintained at a predetermined fixed distance. Is performed.

Further, the signal processing circuit compares the slag level position in the furnace with predetermined upper and lower limit values, and outputs an antenna elevating control signal of a fixed antenna rising amount when the slag level position is equal to or smaller than the lower limit value. When the slag level position is larger than the lower limit value and equal to or larger than the upper limit set value, an antenna elevating control signal of a fixed antenna descent amount is output and input to the antenna elevating device. The control signal raises and lowers the antenna by a certain value, and controls the raising and lowering of the antenna so that the distance between the antenna and the slug surface is kept within a predetermined fixed distance range.

Further, the transmitting antenna and the receiving antenna function as a waveguide on the entire inner side, and a metal inner tube having a large-diameter portion whose inner side functions as a horn antenna at the tip and a metal outer tube surrounding the inner tube. The distal ends are joined, and a partition member is interposed almost entirely between the inner pipe and the outer pipe to form two cooling water passages communicating with the distal ends of these two pipes. The inner tube and the outer tube can remove the heat received in the furnace, efficiently cool, improve the directivity even in an atmosphere where the inside of the furnace is extremely hot, and use it with an improved S / N ratio. it can.

In addition, by injecting a purging gas from a gas purge port provided on the proximal end side of the inner tube, the gas is discharged from the distal end of the inner tube, and purges the inner surface of the distal end functioning as an antenna of the enlarged portion of the inner tube. In addition, the cooling effect of the cooling water is not reduced, and the maintenance is facilitated.

Furthermore, the transmitting antenna and the receiving antenna function as a waveguide on the entire inner side, and the first and second metal inner pipes having a diameter-enlarging portion on the inner end functioning as a horn antenna, and the inner pipes thereof. The distal end portion of the surrounding outer tube made of metal was joined, and a partition member was interposed almost entirely between the inner tube and the outer tube to form two cooling water passages communicating with the distal end portions of both the tubes. Therefore, the inner tube and the outer tube receive heat received in the furnace by the cooling water flowing through the cooling water passage, thereby efficiently cooling the antenna, and can be used even in an atmosphere where the inside of the furnace has a considerably high temperature. In addition, this water-cooled horn antenna purges the inner surface of the distal end functioning as a horn antenna of the inner pipe enlarged portion by injecting a purge gas from a gas purge port provided on the base end side of the inner pipe, and cooling water. The maintenance effect of the antenna is facilitated without lowering the cooling effect of the antenna.

In the case where the transmitting antenna and the receiving antenna are water-cooled parabolic antennas, the primary radiator forms a cooling water channel with a double pipe or triple pipe structure constituting a waveguide and a feeder, and is guided by the cooling water flowing through the cooling water channel. The heat received by the wave tube and the feeder in the furnace is removed, and the reflector forms the outer periphery of a reflector having a parabolic curved surface facing the opening surface of the primary radiator and a back plate disposed on the back of the reflector. Joining, a partition member is interposed between the reflector and the back plate to form a cooling water channel, and the cooling water flowing through the cooling water channel removes the heat received by the parabolic curved surface facing the inside of the furnace, thereby reducing the efficiency of the antenna. It can be well cooled and used in a furnace with a high temperature atmosphere.

Further, the inner surfaces of the waveguide and the feeder of the primary radiator and the parabolic curved surface of the reflector are gas-purged, so that the cooling effect of the cooling water is not reduced and the maintenance of the antenna is facilitated.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, the same components as those of the conventional example are denoted by the same reference numerals, and the description of the duplicated components will be omitted. 12 is a high-sensitivity microwave radar using M-sequence signal processing, 13 is a transmission antenna which is a trumpet-shaped horn antenna, 14 is a reception antenna having the same structure as the transmission antenna 13, and 15 is a microwave radar 12 and a transmission antenna A waveguide 16 connecting the receiving antenna 13 and the receiving antenna 14 is an antenna elevating device for elevating the transmitting antenna 13 and the receiving antenna 14 inserted into the furnace with the microwave radar 12 with respect to the furnace body.

The antenna lifting device 16 includes a cable 17 for suspending the microwave radar 12, a cable winding device 18 for winding and unwinding the cable 17, and a motor 19 for driving the cable winding device 18. Reference numeral 20 denotes a motor drive circuit for the motor 19.

Reference numeral 21 denotes an antenna position measuring device for measuring an antenna position in the furnace from an amount of elevation of the antenna elevating device 16, and a motor.
An encoder 22 for detecting the amount of rotation of 19, and an antenna position calculating means 23 for calculating a cable length wound by the cable winding device 18 from a detection signal of the encoder 22 and calculating an antenna position from the cable length. ing.

Reference numeral 24 denotes a signal processing circuit which processes signals from the microwave radar 12 and the antenna position measuring device 21 to obtain an antenna elevating amount, and raises and lowers the antennas 13 and 14 by the antenna elevating device 16 by the antenna elevating amount.

The signal processing circuit 24 calculates a slag level position of the slag 6 in the furnace from the radar measurement value signal of the microwave radar 12 and the antenna position signal of the antenna position measuring device 21; And a predetermined set value or an upper limit set value and a lower limit set value, and calculates an antenna elevating / lowering amount calculating means 26. 27 is CRT
Display means.

Next, the operation of the above embodiment will be described with reference to the flowchart of FIG. 2 and the graphs of FIGS. 3 (a) and 3 (b).

First, the microwave radar 12 starts measuring the distance between the transmitting antenna 13 and the receiving antenna 14 (hereinafter, referred to as “antenna”) and the slag surface of the slag 6 in the furnace (step S1). Next, the slag level calculation means 25 receives the radar measurement value signal indicating the distance between the antenna and the slag surface measured by the microwave radar 12 and the antenna position signal indicating the antenna position in the furnace measured by the antenna position measurement device 21. Entered (step S2). The antenna position signal is detected by the encoder 22 based on the amount of rotation of the motor 19, and the antenna position calculating means 23 calculates the cable length wound by the cable winding device 18 from the detected value, and determines the antenna position from the cable length. It is obtained by calculation.

The slag level calculation means 25 of the signal processing circuit 24 calculates the slag level position in the furnace from the radar measurement value signal of the microwave radar 12 and the antenna position signal of the antenna position measurement device 21, that is, the antenna and the slag level are calculated from the antenna position. The slag level position is calculated by subtracting the distance from the surface, and the slag level position is displayed on the display means 27 (step
S3).

Next, in the antenna elevating / lowering amount calculating means 26 of the signal processing circuit 24, the distance value indicated by the radar measurement value signal of the microwave radar 12 and the preset value (the distance from the antenna to the slag surface is always 2.0 m) Is set as such, and the difference is obtained as an antenna elevating amount, and an antenna elevating signal indicating the antenna elevating amount is output to the motor drive circuit 20 (step S4). The slag level calculating means 25 and the antenna elevating / lowering amount calculating means 26 of the signal processing circuit 24 receive a value obtained by averaging the measured values of the microwave radar 12 for 10 seconds as a radar measured value signal.

The motor drive circuit 20 to which the antenna elevating signal is input from the antenna elevating amount calculating means 26 drives the cable winding device 18 by rotating the motor 19, and winds the cable 17,
The antenna is extended, and the antenna is moved up and down by the above-mentioned amount of elevation (step S5). In this step, the antenna elevation control is performed so that the antenna position is kept at a fixed distance from the slag surface of the slag 6. Such control is repeatedly performed with the passage of time, and the antenna position is always set at a constant interval, that is, even if the slag surface of the slag 6 in the furnace changes as shown in the graph of FIG. Value. FIG. 3 (b) shows the set values for the passage of time, the antenna and the slug 6 in the antenna elevation control.
3 shows a relationship with a radar measurement value which is a distance from the slag surface. The control of this embodiment is used when the slag surface of the slag 6 has little fluctuation.

Further, another example of the antenna elevating control will be described based on the flowchart of FIG. 4 and the graphs of FIGS. 5 (a) and (b).

First, from the start of the measurement of the distance between the antenna and the slug surface of the slug 6 by the microwave radar 12 in step S11,
Calculate the slag level position of slag 6 in step S13,
The procedure until the slug level position is displayed on the display means 27 is the same as the procedure shown in the flowchart of FIG.

Next, the antenna elevating / lowering amount calculating means 26 of the signal processing circuit 24 compares the radar measurement value signal of the microwave radar 12 with a preset lower limit set value 1 (1.5 m) (step S1).
4) If the distance value indicated by the radar measurement signal is equal to or smaller than the lower limit set value 1, an antenna elevating control signal of a preset antenna lift (1.0 m) is output, and the antenna elevating and lowering is performed. The antenna is raised by 1.0 m by the device 16 (step S15), and the process returns to step S12. When the distance value indicated by the radar measurement value signal is larger than the lower limit set value, it is compared with the upper limit set value 2 (3.0 m) (step
S16) When the radar measurement value is equal to or larger than the upper limit set value 2, an antenna elevating control signal of a predetermined antenna descent amount (1.0 m) is output, and the antenna elevating device 16 controls the antenna. Lower by 1.0 m (step S17). If the radar measurement value is smaller than the upper limit set value 2, the process returns to step S12.

In such a step, the antenna elevation control is performed so that the antenna position is at a distance within a certain range from the slug surface of the slug 6. Such control is repeatedly performed with the lapse of time, and the antenna position always remains within a certain range even when the slag surface of the slag 6 fluctuates as shown in the graph of FIG. It will be maintained between the value and the lower limit setting. FIG. 5 (b) shows the relationship between the upper and lower limit set values with respect to the passage of time in the antenna elevating control and the radar measurement value that is the distance between the antenna and the slug surface of the slug 6. The control of this embodiment is used when the slag surface of the slag 6 fluctuates greatly.

In the above-described embodiment, even if the slag surface of the slag 6 in the furnace fluctuates, the antenna elevation control is performed so that the antenna position is at a fixed distance or within a certain range with respect to the slag surface of the slag 6. As described above, the slag surface of the slag 6 in the furnace descends, and the distance between the antenna inserted in the furnace and the slag surface increases, which is affected by unnecessary reflected signals from the lance 8 in the furnace and the furnace wall. The slag surface of the slag 6 in the furnace rises, the antennas 13 and 14 inserted into the furnace approach the slag surface, and the slag and metal splattered to the antennas 13 and 14 It can be prevented from adhering. Therefore, it is possible to always measure the level of the slag 6 in the normal furnace in the furnace level meter using the microwave radar 12.

In particular, in the measurement of the slag level in the smelting reduction furnace 1, since the reflection of the microwave from the slag surface is weak, the slag adheres to the antennas 13 and 14 and is affected by unnecessary reflected signals from the furnace wall and the like. Therefore, the effect of applying the present invention is great.

Although the above-mentioned embodiment described an example applied to measurement of the slag level of the smelting reduction furnace 1, the slag level in the converter
Of course, it can be applied to the measurement of the molten steel level in the furnace and the raw material level in the blast furnace.

In the above-described embodiment, a wrapped tubular horn antenna that does not perform cooling is used as an antenna to be inserted into the furnace. However, depending on environmental conditions in the furnace to which the in-furnace level meter is applied, an air-cooled antenna or a water-cooled antenna may be used. It may be desirable to use one of the antennas.

Such a water-cooled antenna is shown in FIGS. 6 to 20.

FIG. 6 is a configuration diagram showing one embodiment of a water-cooled antenna, and FIG.
The figure is a sectional view taken along the line AA in FIG. Reference numeral 41 denotes an inner circular tube having a length of about 1000 mm and a diameter of 25 mm made of copper. The tip at the left end in the drawing has a length of about 200 mm and a taper angle of ± 3.
It has an enlarged diameter portion 41a of up to 10 °. The inner circular tube 41 functions as a waveguide on the entire inner side, and the inside of the tip of the enlarged diameter portion 41a functions as a horn antenna.The diameter of the inner circular tube 41 is 0.66λ of the wavelength of the microwave used. It is designed to be in the range of 0.91λ. 42 is formed of steel surrounding the inner pipe 41, a length of about 800 mm that functions as a partition member, a middle pipe having a diameter of 40 mm, and 43 is formed of steel surrounding the inner pipe 41 and the middle pipe. It is an outer tube with a length of about 800mm and a diameter of 60mm. The distal end of the enlarged diameter portion 41a of the inner circular tube 41 and the distal end of the outer circular tube 43 are joined by welding, and a gap formed between these distal ends is closed. The two cooling water passages 44 communicating with the inner pipe 41 and the outer pipe 43 at the distal end side by the middle pipe 42 functioning as a partition member are provided between the inner pipe 41 and the outer pipe 43.
a, 44b are formed. 45 is a cooling water passage 44a on the outer pipe 43 side
Water supply port provided on the base end side which is the right end side in the drawing of
46 is a drain port provided on the base end side which is the right end side in the drawing of the cooling water passage 44b on the inner circular pipe 41 side, 47 is provided on the base end side of the inner circular pipe 41 and communicates with the inside of the inner circular pipe 41 A gas purge port with a diameter of 6 mm, the diameter of which is 1/1 of the wavelength of the microwave used.
Designed to be 4 or less. Reference numeral 48 denotes a flange provided at the base end of the inner circular tube 41.

In the water-cooled antenna having such a configuration, of the two cooling water passages 44a and 44b formed by the intermediate pipe 42 positioned as a partition member between the inner pipe 41 and the outer pipe 43, one of the outer pipes is used. If the cooling water flows through the water supply port 45 of the cooling water passage 44a on the 43 side, the cooling water reaches the inner circular tube 41 and the enlarged diameter portion 41a through the cooling water passage 44a, and then the other inner circular tube 41 side The water is drained to the outside from the drain 46 through the cooling water passage 44b. Accordingly, the heat received in the furnace by the inner circular tube 41 and its enlarged diameter portion 41a and the outer circular tube 43 located in the furnace is efficiently removed by the cooling water flowing through the cooling water passages 44a and 44b. For this reason, the inner pipe
41 and the outer circular tube 43 have heat resistance at an ambient temperature of 1500 ° C. Therefore, even if the enlarged diameter portion 41a functioning as the antenna of the inner circular tube 41 is used by being inserted deeply into the furnace, the directivity is increased, the S / N ratio is improved, and the frequency of the microwave used is 10 GHz. In this case, the antenna has a performance of an antenna gain of 20 dB and can measure accurately.

Further, a gas purge port 47 provided on the base end side of the inner pipe 41 is provided.
For example, when a purge gas such as nitrogen, air, or argon is caused to flow, the gas enters the inner circular tube 41, is discharged from the tip of the inner circular tube 41, and has a larger diameter portion 41a of the inner circular tube 41. Purging the inner surface of the tip that functions as an antenna to the nose, makes it easier to maintain without reducing the cooling effect of the cooling water. In this embodiment, a water supply port 44 is provided at the base end side of the cooling water passage 44a on the outer pipe 43 side.
Is provided to cool the outer surface of the outer tube 43 with fresh cooling water, because the outer surface of the outer tube 43 is located in the furnace,
This is because the inner surface of the inner tube 41 does not come into contact with the hot air in the furnace due to the gas purge, so that the outer surface of the outer tube 43 that comes into contact with the hot air is efficiently cooled.

FIG. 8 is a block diagram showing another embodiment of the water-cooled antenna, FIG. 9 is a cross-sectional view taken along line AA of FIG. 8, and FIG. 10 is an interposition between the inner circular pipe and the outer circular pipe. It is an explanatory view showing a partition member to be performed. In the figure, the same components as those of the embodiment shown in FIGS. 6 and 7 are denoted by the same reference numerals as those of the embodiment, and the description of the same components will be omitted. In this embodiment, the inner pipe 41 and the outer pipe 43
The two cooling water passages 44a and 44b are formed with a partition plate 52 interposed therebetween, and the manufacturing cost is lower than in the above-described embodiment. Since the operation and effect of this embodiment are the same as those of the above embodiment, description of the operation and effect of this embodiment will be omitted.

Further, although the inner tube 41 of these embodiments is entirely formed of copper, it is sufficient that the inner tube 41 has a function as a waveguide, and the inner surface side of the inner tube 41 is made of copper. Needless to say, it may be formed of steel so as to have strength and the other portions have strength.

Although the above-described embodiment shown in FIGS. 6 to 10 is manufactured using the inner circular pipe 41 and the outer circular pipe 43, both of which are circular, the inner pipe and the outer pipe having a square or polygonal shape are used. However, it is a matter of course that the present invention can be implemented, and when the inner pipe has a rectangular shape, its diameter dimension is 0.62λ to 0.95 in the long side diameter.
λ is designed to be in the range of 0.28λ to 0.42λ in the short side diameter.

FIG. 11 is a side view of a still further embodiment of the water-cooled horn antenna viewed from the tip side, FIG. 12 is a sectional view taken along line AA of FIG. 11, and FIG. 13 is a sectional view taken along line BB of FIG. Fig. 14, Fig. 14
FIG. 15 is a diagram showing a distal end side of a cross section taken along line CC in FIG. 15, and FIG. 15 is a diagram showing a base end side of a cross section taken along line CC in FIG.

In FIG. 11, reference numerals 51 and 52 denote inner pipes made of copper, and the two inner pipes 51 and 52 are installed in parallel. At the tip of the inner tubes 51, 52 on the left side in the figure,
1a and 52a, and flanges 51b and 52b are provided at the base ends of the inner tubes 51 and 52, respectively.

The entire inside of the inner tubes 51 and 52 functions as a waveguide, and the enlarged diameter portions 51a and 52a provided at the tip of the inner tubes function as horn antennas, for propagating microwave signals from the radar device and for transmitting signals from the antennas. It radiates and receives microwave signals and propagates signals to radar equipment.

The inner diameter of the inner tubes 51 and 52 is determined by the wavelength of the microwave signal used, and the inner diameter a is determined to be in the range of 0.58λ to 0.76λ with respect to the wavelength λ of the microwave signal used.

In addition, the performance of the horn antenna is determined by the shape of the inner surface of the enlarged diameter part, the diameter of the tip of the enlarged diameter part is increased, and the overall length of the enlarged diameter part is increased, thereby increasing the gain of the horn antenna and increasing the directivity of signal radiation of the antenna. It can be improved. In the present example, the inner diameter of the distal end portion was 3.7λ, the total length of the enlarged diameter portion was 10.7λ, and a gain of about 20 dB was obtained.

Reference numeral 53 denotes a partition pipe formed of steel surrounding the inner pipes 51 and 52, and the left end in the figure has a hemispherical shape and an opening 53a is provided at the front end, and the distal end of the partition pipe 53 is connected to the inner pipes 51 and 52. The enlarged diameter portions 51a and 52a are penetrated.

Numeral 54 is an outer tube formed of steel surrounding the inner tubes 51 and 52 and the partition tube 53, and the tip of the outer tube 54 and the enlarged diameter portion of the inner tube.
The tips of 51a and 52a are joined by welding, and the gap formed between these tips is closed. And the outer tube 54
Cooling water passages 53a and 55b communicating with the partition pipe 53 at the opening 53a at the tip of the partition pipe are formed entirely between the inner pipes 51 and 52.

Reference numeral 56 denotes a water supply port provided on the base end side of the outer cooling water passage 55a, and reference numeral 57 denotes a drainage port provided on the base end side of the inner water supply passage 55b. In the drawing, 58 and 59 are gas purge ports provided on the base end sides of the inner tubes 51 and 52, and the diameter thereof is designed to be 1/4 or less of the wavelength of the microwave signal used.

In the water-cooled antenna of this embodiment, the inner tubes 51 and 52 and the outer tube 54
Between the two cooling water passages 55 formed by the partition pipes 53
Of the a and 55b, if the cooling water flows through the water supply port 56 provided at the base end of the cooling water passage 55a on one outer tube side, the cooling water reaches the distal end through the cooling water passage 55a. Later, it flows into the cooling water channel 55b on the inner pipe side through the opening 53a at the tip of the partition pipe, and is drained from the drain port 57 on the base end side through the cooling water channel 55b. Therefore, when the water-cooled antenna is inserted into the furnace, the heat received in the furnace by the inner tubes 51 and 52, the enlarged diameter portions 51a and 52b, and the outer tube 54 is removed by the cooling water flowing through these cooling water passages. . In the water-cooled antenna of the present embodiment, a sufficient cooling effect was obtained even at a furnace atmosphere temperature of 1500 ° C., and it was possible to insert the antenna deep inside the furnace and perform measurement.

Also, when a purge gas such as nitrogen, air, or argon flows from the gas purge ports 58 and 59 provided on the proximal ends of the inner tubes 51 and 52, the gas flows through the inner tubes 51 and 52,
The inner surfaces of the enlarged portions 51a and 52a at the tips of the inner tubes, which are emitted from the tips of the inner tubes 51 and 52 and function as horn antennas, are purged to facilitate maintenance of the antenna without reducing the cooling effect of the cooling water.

In the present embodiment, a water supply port 56 is provided at the base end side of the cooling water passage 55a on the outer tube side to supply cooling water, but this is achieved by the gas pipe purge of the inner tube 51 having less contact with hot air in the furnace. , 52 in order to efficiently cool the outer surface of the outer tube 54 that comes into contact with the hot air in the furnace.

FIG. 16 is a side view of still another embodiment of the water-cooled horn antenna viewed from the distal end side, FIG. 17 is a sectional view taken along line AA of FIG. 16, and FIG. 18 is a line BB of FIG. Line sectional view, FIG.
FIG. 17 is a diagram showing a tip side of a cross section taken along line CC of FIG. 17, and FIG.
It is a figure which shows the base end side of the CC line cross section of the figure. In FIG.
Those having the same functions as those of the embodiment shown in FIG.

In the figure, reference numeral 70 denotes an integrated large-diameter portion in which the large-diameter portions 51a and 52a shown in FIG. 11 are integrated into a single mold, and the inner pipe 51 and the inner pipe 52 are connected to each other. Internal surface 70a and 7
0b each functions as a horn antenna. Also,
The distal end of the partition pipe 53 has a straight pipe shape, and forms a cooling water passage communicating between the inner pipes 51 and 52 and the outer pipe 54 at the distal end.

In this embodiment, as compared with the embodiment shown in FIG. 11, the shapes of the enlarged diameter portion and the partition tube are changed, so that the production process can be simplified and the production cost can be reduced. The operation and effect of the water-cooled antenna according to this embodiment are the same as those of the above-described embodiment.

In these embodiments, the inner tubes 51 and 52 are made of copper in order to make the inner tubes function as waveguides, but only the inner surface of the inner tube is made of copper and the other portions are made of steel to provide strength. It is also possible to form.

In these embodiments, the inner pipe, the partition pipe and the outer pipe are circular pipes having a circular cross section. However, it is also possible to use an inner pipe having a square or polygonal cross section.

FIG. 21 is a side view of one embodiment of a water-cooled parabolic antenna,
FIG. 22 is a front view of the same embodiment, FIG. 23 is a sectional view showing the structure of a primary radiator, FIG. 24 is a sectional view showing the structure of a reflector, FIG.
FIG. 25 is a configuration diagram showing a spacer.

In FIG. 22, 71 and 72 are transmitting and receiving parabolic antennas, 73 and 74 are water-cooled waveguides and feeders that function as primary radiators of parabolic antennas, and 75 and 76 are primary radiators. It is a water-cooled reflector of a parabolic antenna having a parabolic surface facing the opening surface.

Primary radiators 73, 74 of the water-cooled parabolic antenna of the present embodiment
As shown in FIG. 23, an inner tube 77 functioning as a waveguide and a feeder, and an outer tube 78 made of steel arranged such that the inner tube and the tip are joined by welding and wrapped around the inner tube. And a partition pipe 79 made of steel interposed between the inner pipe 77 and the outer pipe 78, and has a triple pipe structure forming cooling water passages 80a and 80b communicating with each other at the distal ends. In the primary radiator of this embodiment, by passing water through the cooling water passages 80a and 80b, the heat received by the primary radiator in the furnace is removed, and the primary radiator is cooled.

Further, the reflector of the water-cooled parabolic antenna of this embodiment is:
As shown in FIG. 24, a reflecting plate 81 constituting a parabolic curved surface facing the opening of the primary radiator, a reflecting plate 81 and an outer peripheral portion are joined, and a back plate 82 arranged on the back surface of the reflecting plate 81, A partition plate 83 interposed between the reflection plate 81 and the back plate 82, and a spiral spacer 84 interposed between the reflection plate 81 and the partition plate 83, the reflection plate 81 and the back plate 82 A spiral cooling water path 85a and a cooling water path 85b are formed between the partition plate 83 and the spacer 84. Reference numeral 86 denotes a water supply pipe connected to the center of the partition plate 83 and connected to the cooling water passage 85a. Reference numeral 87 denotes a drain pipe connected to the back plate 82 and connected to the cooling water passage 85b on the back side. In the reflectors 75 and 76 of this embodiment, when cooling water flows through the water supply pipe 86, the cooling water flows through the cooling water passage 85a from the center to the outer periphery,
The water flows around the outer peripheral portion, flows through the cooling water passage 85b, and is drained from the drain pipe 87. Therefore, the cooling water flowing through the cooling
The heat received by 81 from inside the furnace is removed and the reflectors 75 and 76 are cooled. At this time, since the cooling water passage 85a is formed in a spiral shape, the cooling water can uniformly remove the heat from the reflecting plate 81 and uniformly cool the reflecting plate 81. It is possible to prevent the parabolic surface from being distorted due to the deviation and the antenna performance from deteriorating due to the waveform.

In the water-cooled parabolic antenna of the present embodiment, sufficient cooling performance was obtained even at a furnace atmosphere temperature as high as about 1500 ° C., and it became possible to install the antenna in a converter or the like.

FIG. 26 is a side view of another embodiment of the water-cooled parabolic antenna, and FIG. 27 is a front view of the embodiment. In FIG. 26, components having the same functions as those in the embodiment of FIG. 21 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 4, 90 and 91
Are supporting members that support the primary radiators of the transmitting parabolic antenna and the receiving parabolic antenna, respectively.

In the water-cooled parabolic antenna according to the present embodiment, the primary radiator 73 of the transmitting antenna and the primary radiator 74 of the receiving antenna are supported by the supporting members 90 and 91, so that the mechanical strength of the primary radiator is increased and the primary radiator is increased. The devices 73 and 74 can be prevented from being deformed due to the bias of the heat received from the furnace, and the relative performance between the primary radiator and the reflector can be prevented from deteriorating and the antenna performance can be prevented from deteriorating. In this example, heat-resistant ceramics were used as the support members 90 and 91.

In the water-cooled parabolic antenna of this embodiment, the primary radiator of the waveguide and the feeder having the triple tube structure is used, but the partition plate is provided between the inner tube and the outer tube functioning as the waveguide and the feeder. It is also possible to use a waveguide and feeder having a double tube structure that is mounted to form a cooling channel.

Further, in the present embodiment, the inside of the waveguide of the primary radiator, the inner surface of the feeder and the parabolic curved surface of the reflector are purged with a purging gas such as nitrogen, air, and argon without reducing the cooling effect of the cooling water. Maintenance of the antenna can be facilitated.

By the way, although the in-furnace level meter of this embodiment uses the microwave radar 12 using M-sequence signal processing, other microwave radars such as a pulse modulation radar can be used. However, the microwave radar 12 using the M-sequence signal processing can detect a reflected wave from an object having a low reflectance with high sensitivity, and even if the reflected microwave from the slag surface is weak, the slag adheres to the antenna. There is an advantage that it is hardly affected by unnecessary reflected signals from the furnace wall. Therefore, in order to clarify the advantage, a detailed configuration and operation of the microwave radar 12 using the M-sequence signal processing will be described below.

FIG. 28 is a block diagram showing an embodiment of a microwave radar using M-sequence signal processing, wherein 101 and 102 are clock generators, 103 and 104 are pseudo-random signal generators, and 105 to 10
Reference numeral 9 denotes a multiplier, which is constituted by, for example, a double balanced mixer. 110 to 112 are low-pass filters, 113 and 114 are dividers, 115 and 116 are squarers, 117 is an adder, 118 is a time measuring instrument, 119 is a carrier oscillator, 120 is a hybrid combiner, 121 is a transmitter, and 122 is a receiver. , 123 is a transmitting antenna, 124 is a receiving antenna, and 125 is a target.

FIG. 29 is a waveform chart for explaining the operation of FIG.

FIG. 30 is a configuration diagram of a 7-bit M-sequence signal generator, in which 130 is a seven-stage shift register, and 131 is an exclusive OR circuit.

The operation of FIG. 11 will be described with reference to FIGS. 29 and 30. As the pseudo-random signal generators 103 and 104, for example, an M-sequence signal generator can be used. FIG. 30 shows the configuration of a 7-bit M-sequence signal generator.
It comprises a seven-stage shift register composed of couple logic elements and an exclusive OR circuit 131. The M-sequence signal has a code “1” (corresponding to + E of positive voltage) and “0”
(Corresponding to -E of the negative voltage), which is a cyclic circulating signal. In the case of 7 bits in the present example, 2 ⁷ −1 = 127 (1
When a signal of 27 chips is generated, one cycle is completed, and a cyclic signal is generated by repeating this cycle. Since the pseudo-random signal generators 103 and 104 are composed of the same circuit, the output signals of both become signals of exactly the same pattern.
However, since the supplied clock frequency is slightly different, one cycle thereof is also slightly different. In addition to the M-sequence signal, a gold-sequence signal, JPL
A sequence signal can be used. Clock generator 101,
Both 102 have a built-in crystal oscillator and generate a clock signal with a sufficiently stable frequency, but their generation frequencies are slightly different. Generating frequency f ₁ of the clock generator 101 in this embodiment is 100.004MHz, occurrence frequency f of the clock generator 102
₂ is 99.996 MHz, and the frequency difference is f ₁ −f ₂ = 8 KHz. Clock signals f ₁ and f ₂ output from clock generators 101 and 102 are supplied to pseudo-random signal generators 103 and 104, respectively. The pseudo-random signal generators 103 and 104 have slightly different periods due to the frequency difference between the driving clock signals, but have the same pattern.
And it outputs a sequence signal M ₁ and M _2. Now two M-sequence signals M ₁
And when determining the period of M _2, the period of _{M 1 = 127 × 1 / 100.004MHz} ≒ 1269.9492ns M 2 cycle = 127 × 1 / 99.996MHz ≒ 1270.0508ns . That is, the two M-sequence signals M ₁ and M ₂ are approximately 1270 ns (10
^-9 seconds), but there is a time difference of about 0.1 ns between the two periods. Thus is generated by circulating the two M-sequence signals M ₁ and M _2, when the patterns of the two M-sequence signal at a certain time t _a match, the deviation of 0.1ns for each time of one period A difference of 10 ns occurs between the two signals after 100 cycles. Here, the M-sequence signal is 12
Since seven signals are generated, the generation time of one signal is 10 ns. Therefore we say that the deviation of 10ns arises between the two M-sequence signals M ₁ and M ₂ corresponds to M-sequence signal is shifted one minute. The output M ₁ is multiplier 105 and 106 of the pseudo random signal generator 103, also a pseudo-random signal generator 104
Output M ₂ of respectively supplied to multipliers 105 and 107.

The carrier generator 119 oscillates a microwave having a frequency of about 10 GHz, for example, and its output signal is distributed by the distributor 113,
The signal is supplied to the multiplier 106 and the hybrid combiner 120. Multiplier 106 is formed of, for example, a double-balanced mixer, and has a carrier having a frequency of about 10 GHz input from distributor 113 and an M-sequence signal M input from pseudo-random signal generator 103.
Multiplication by ₁ is performed, and a spread spectrum signal obtained by phase-modulating the carrier is output and supplied to the transmitter 121. The transmitter 121 power-amplifies the input spread spectrum signal, converts the spread spectrum signal into an electromagnetic wave via the transmission antenna 13, and radiates it to the target 125. Here, the wavelength of the electromagnetic wave having a frequency of 10 GHz in the air is 3
cm, which is sufficiently larger than, for example, the size (diameter) of the dust in the furnace for steelmaking, so that it is less susceptible to dust and the like.
Further, for example, a horn antenna is used as the transmitting antenna 13 and the receiving antenna 14, and the directivity is sharply narrowed so that the reflected power from objects other than the object to be measured is reduced as much as possible. The antenna gain is about 20 dB, for example. The electromagnetic wave radiated from the transmitting antenna 13 toward the target 14 is reflected by the target 125 which is, for example, the slug 6, converted into an electric signal via the receiving antenna 14, and is converted into an electric signal.
Is input to The timing at which the input signal is supplied to the receiver 122 is naturally delayed by the propagation time of the electromagnetic wave from the timing at which the electromagnetic wave is radiated from the transmitting antenna 13 to the time at which the electromagnetic wave reciprocates the distance to the target 125 and reaches the receiving antenna 14. ing. The receiver 122 amplifies the input signal and supplies it to the multiplier 107.

On the other hand, pseudo-random signal generators 103 and 104
Are respectively multiplied by the M-sequence signals M ₁ and M _2, and the time-series signal of the multiplied value is supplied to the low-pass filter 110. FIG. 29A shows this low-pass filter 11.
This is a waveform showing an input signal to 0, that is, a time series signal which is a multiplied value of the multiplier 105, and an output voltage of + E when two pseudo random signals input to the multiplier 105 have the same phase. Continues, but when the phases of both signals do not match, the output voltages of + E and -E are randomly generated. The low-pass filters 110 to 112 have a kind of integration function by performing frequency band limitation, and as an integration signal of a correlation operation value of both signals, when the phases of both signals match,
A pulse signal as shown in FIG. 29 (a) is output. When the phases of the two signals do not match, the output becomes zero. Therefore, a pulse-like signal is periodically generated at the output of the low-pass filter 110. This pulse signal is supplied to the time measuring device 118 as a time reference signal. When the period T _B of the reference signal is calculated by the following equation (1), the 7-bit pseudo-random signal in the case of the present example M-sequence signal M ₁ and M ₂
Since the wavelength N of one period is 2 ⁷ -1 = 127, f ₁
= 100.004 MHz, f ₂ = 99.996 MHz, so T _B = 15.875 ms
Becomes The reference signal and its period T _B is shown in the FIG. 29 (d).

The above equation (1) is given as follows.

Let the repetition frequency of the first pseudo-random signal be f ₁ ,
Let the repetition frequency of the pseudo-Radam signal be f ₂ and the pattern of each pseudo-random signal be the same. Where f ₁ > f ₂
And

When the cycle reference signal obtained by taking the correlation between the first pseudo random signal and the second pseudo random signal to be transmitted is the maximum value and T _B, the first pseudo-random contained between the T _B The difference between the wave number of the signal and the wave number of the second pseudo-random signal is exactly the wave number N of one cycle.

That is, T _B · f ₁ = T _B · f ₂ + N By rearranging the above equation, T _B is given by the following equation (1).

T _B = N / (f ₁ −f ₂ ) (1) That is, as the difference between the two clock frequencies is smaller, the period T _{B at} which the reference signal has the maximum value becomes larger.

The multiplier 107 receives the received signal from the receiver 122 and the M-sequence signal M ₂ from the pseudo-random signal generator 104,
Multiplication of both signals is performed. Multiplication result of the multiplier 107, when the modulated phase of the received signal transmission carrier by the first M-sequence signal M ₁ is phase-modulated, the second M-sequence signal M ₂ are in phase is output as a carrier signal phase alignment, is supplied to the random output of a carrier wave divider 114 of the phase when the modulated phase and M-sequence signal M ₂ phases of the received signals are different. Distributor 114 distributes an input signal into two, the distribution output R ₁ and R ₂ multipliers 108
And 109. The hybrid coupler 120, to which a part of the carrier for transmission is supplied from the divider 113, converts the input signal into a signal I having an in-phase component (a phase of 0 degree) and a signal Q having a quadrature component (a phase of 90 degrees). Output, and multipliers 108 and 1 respectively.
Supply to 09. The multiplier 108 performs a multiplication between the signal R ₁ inputted from the distributor 114 and the signal inputted from the hybrid coupler 120 I (i.e. the output phase with the signal of the carrier generator 119), similarly the multiplier 109 is input signal Q (i.e. carrier oscillator 119 outputs a 90 ° phase different signal) performs multiplication of said signal R _2, respectively phase 0 degree component in the received signal (I · R ₁₎ and phase 90 degrees component ( Q · R ₂ )
Output as a test signal. Signals I · R ₁ as the target detection signal and the Q · R ₂ each low-pass filter 111 and 1
Supplied to 12. The low-pass filters 111 and 112 have an integration function by limiting the frequency band, and integrate the correlation operation value of two signals. That is, the signal R ₁ input from the output of the multiplier 107 to the multiplier 108 via the distributor 114.
When the phase of the signal I input to the multiplier 108 from the hybrid coupler 120 matches, and when the phase of the signal R ₂ and the signal Q input to the multiplier 109 also match, the multipliers 108 and The output signal of 109 is a pulse signal of a constant polarity (pulse signal of voltage + E), and a large positive voltage is obtained at the outputs of the low-pass filters 111 and 112 obtained by integrating these signals. Also when the phase mismatch of the signal R ₁ and the signal I, and when the phase mismatch of the signal R ₂ and the signal Q, the output signal of the multiplier 108 and 109, both positive and negative polarities of the pulses varies randomly each Signals (ie, voltages + E and-
E pulse signal), and the outputs of the low-pass filters 111 and 112 obtained by integrating this signal become zero. The signals of the 0-degree phase component and the 90-degree phase component integrated by the low-pass filters 111 and 112 as described above are squared 115 and 116, respectively.
Supplied to Each of the squarers 115 and 116 squares the amplitude of the input signal, and outputs the output signal of the arithmetic result to the adder 11.
Supply 7 The adder 117 adds the two input signals, inputs a pulse-like power signal as shown in FIG. 29 (c), and supplies it to the time measuring device 118. Now the maximum value occurrence time of the detection signal and t _b. Thus the phase 0 degree component and the phase 90 ° component of the transmission carrier wave from the signal obtained by the correlation processing between the received signal and the M-sequence signal M ₂ detects each square after integration of the detection wave signal respectively Calculate this 1
Although the method of obtaining the object detection signal as the sum of the squares of the pair is somewhat complicated, a highly sensitive object detection signal can be obtained. Also, since a correlation output of a pseudo-random signal such as an M-sequence signal is obtained, a measurement system having a high signal-to-noise ratio (S / N) can be realized in order to reduce the influence of noise and enhance the signal. it can. Of course, as a carrier detection method, there is a detection method using a crystal, and although the sensitivity is reduced, the configuration is simplified, and this method can be adopted depending on the specification and cost.

Time measuring instrument 118 measures the time T _D between occurrence time t _b of the maximum value of the detection signal input from the generation time t _a and the adder 117 of the maximum value of the reference signal input from the low-pass filter 110 . For this reason, the time measuring device 118 has a function of detecting the maximum value occurrence time of the two input signals. For example, the input voltage value is sequentially sampled and held by the clock signal, and the sampled value by the current clock signal and one of the clock signal are obtained.
By successively comparing the previous sample value with a voltage ratio meter,
By detecting the time at which the input signal changes from an increasing state to a decreasing state with respect to time, the time at which the maximum value of the input signal occurs can be detected. The time T _D is shown in FIG.
It is shown as the time between the maximum generation time t _b of maximum occurrence time t _a and (c) detection signal shown in the reference signal shown in. This time T _D is, as shown in the following equation (2), f ₁ / (f ₁ −) of the propagation time τ during which the electromagnetic wave actually travels between the transmitting and receiving antennas 13 and 14 and the target 125.
f ₂ ) times as large as in time.

The above equation (2) is given as follows.

A carrier wave phase-modulated by the first pseudo-random signal is transmitted, reflected by an object, and a propagation time until it is received again is set to τ. The received signal is demodulated by a second pseudo-random signal, and coherent detection is performed. wave number of the time pulse-like signal of the target object detection signal obtained is generated, when the time difference measured from the pulse-shaped signal generation time of the reference signal and T _D, a second pseudo random signal generated between T _D , from the wave number of the first pseudo random signal generated between T _D, since less only the wave number of the first pseudo random signal generated in the τ time, the following equation is established.

T _D · f ₂ = T _D · f ₁ −τ · f ₁ By rearranging the above equation, T _D is given by the following equation (2).

T _D = τ · f ₁ / (f ₁ −f ₂ ) (2) That is, the propagation time τ is temporally expanded by f ₁ / (f ₁ −f ₂ ) times, or T is reduced. Measured as _D.

In the case of this example, since f ₁ = 100,004 MHz and f ₂ = 99.996 MHz, the time is extended to 12,500 times and the equation (3) is obtained.

T _D = 12,500τ (3) The time T _D in the equation (3) is obtained for each period T _{B of the} reference signal.

As described above, in the present embodiment, since the measurement time is greatly extended, it is possible to accurately measure the distance to the object from a short distance. Therefore, it can be said that it is also suitable as a short-range level measuring device such as a slag level and a molten steel level in a furnace.

Therefore the target from the transmitting and receiving antennas 13 and 14
When the distance x meters to 125 is obtained by equation (3), equation (4) is obtained.

x = (f ₁ −f ₂ ) / 2f ₁ · v · T _D = 1.2 × 10 ⁴ · T _D (4) where v is the propagation velocity.

In this embodiment, the configuration in which the transmitting antenna and the receiving antenna are separated and two antennas are provided has been described. However, the present invention is not limited to this, and one antenna is shared for transmission and reception, and the directional coupler or the duplexer is used. May be added to the antenna system to separate transmission and reception signals.

Further, in the present embodiment, an example of a microwave of about 10 GHz is shown as a carrier, but not only electromagnetic waves such as millimeter waves, but also light, sound waves, and electromagnetic waves such as ultrasonic waves can be used as carrier waves. is there.

[Effects of the Invention] As described above, the present invention provides a signal processing circuit for measuring a distance between an antenna and a slag surface in a furnace measured by a microwave radar and a laser measurement signal and an antenna position measured by an antenna position measuring device. Calculates the slag level position in the furnace from the antenna position signal, and compares the slag level position with a predetermined set value or upper and lower limit set values to calculate an antenna elevating amount, and the antenna elevating amount of the antenna elevating amount is calculated. A control signal is input to the antenna elevating device, and the antenna elevating device raises and lowers the antenna according to the antenna elevating control signal, so that even if the slag surface in the furnace fluctuates, the distance between the antenna and the slag surface is always a predetermined distance. Or because it was kept within a certain distance range,
When the slag surface in the furnace is lowered, the distance between the antenna inserted in the furnace and the slag surface increases, and it is possible to avoid being affected by unnecessary reflected signals from the lance and the furnace wall in the furnace. When the slag surface in the furnace rises, the antenna inserted into the furnace and the slag surface come close to each other, and it is possible to prevent the slag and metal scattered from sticking to the antenna, and particularly to measure the slag level. Since the reflection of microwaves from the slag surface is weak, it is always possible to measure the level of the slag level in the normal furnace even if it is susceptible to slag attachment to the antenna or unwanted reflected signals from the furnace wall etc. There is an effect that it can be implemented.

The transmitting and receiving antennas used in the in-furnace level meter include a metal inner tube having a diameter-enlarging portion whose entire inner side functions as a waveguide and the inner side functions as a horn antenna, and an inner tube. Joining the tip of the surrounding outer tube made of metal, interposing a partition member almost entirely between the inner tube and the outer tube,
Two cooling water passages communicating with each other on the distal end side of these two pipes are formed, or first and second metal inner pipes each having an enlarged diameter portion functioning as a horn antenna at the distal end; A metal outer pipe surrounding the pipe, joining the enlarged diameter portions at the first and second inner pipe tips and the tip of the outer pipe, and forming a partition member almost entirely between the inner pipe and the outer pipe. The cooling water flowing through the cooling water passages is used to form two cooling water passages that communicate with each other at the tips of the two pipes, so that the inner pipe and the outer pipe receive heat received in the furnace and cool. As a result, the enlarged diameter of the inner tube functioning as an antenna can be brought closer to the measurement object in the furnace, which has the effect of improving directivity, improving the S / N ratio, and enabling accurate measurement. . Furthermore,
Since a gas purge port is provided on the base end side of the inner pipe, a purge gas flows from the gas purge port to purge the inner surface of the distal end functioning as an antenna of the enlarged portion of the inner pipe,
This has the effect of facilitating maintenance without reducing the cooling effect of the cooling water.

Further, in the above-mentioned water-cooled horn antenna, two antennas for transmitting and receiving microwave signals are formed as one cooling structure, and the size of the antenna is reduced and the outer shape is simplified by integrating the two antennas. There is also an effect that the installation and maintenance of the device can be facilitated.

Furthermore, in the case where the transmitting antenna and the receiving antenna are water-cooled parabolic antennas, since the primary radiator forms a cooling water channel by a double pipe or a triple pipe structure constituting a waveguide and a feeder, the cooling water flowing through the cooling water channel is used. The heat received by the waveguide and the feeder in the furnace is removed, and the reflector has the outer periphery of a reflector having a parabolic curved surface facing the opening surface of the primary radiator and a back plate disposed on the back of the reflector. And a partition member is interposed between the reflection plate and the back plate to form a cooling water passage, so that the cooling water flowing through the cooling water passage removes heat received by the opposed parabolic curved surface in the furnace, thereby removing the antenna. Can be efficiently cooled and can be used even in a furnace in a high-temperature atmosphere.

Also, since the inner surface of the waveguide and feeder of the primary radiator and the parabolic curved surface of the reflector are gas purged, the effect of cooling the cooling water is not reduced, and the effect of facilitating the maintenance of the antenna is also obtained. Have.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a flowchart showing one antenna elevation control procedure of the embodiment, and FIG. 3 (a) shows a relationship between an antenna position and a slag surface. FIG. 3 (b) is a graph showing the relationship between set values and radar measurement values, FIG. 4 is a flowchart showing another antenna elevation control procedure of the embodiment, and FIG. 5 (a) is the antenna position FIG. 5B is a graph showing a relationship between a set value and a radar measurement value, FIG. 6 is a configuration diagram showing an embodiment of a water-cooled antenna, and FIG. FIG. 6 is a sectional view taken along line AA of FIG. 6, FIG. 8 is a configuration diagram showing another embodiment of the water-cooled antenna, and FIG.
FIG. 10 is a sectional view taken along line AA of FIG. 10, FIG. 10 is an explanatory view showing a partition member interposed between an inner pipe and an outer pipe, and FIG. 11 is still another embodiment of a water-cooled horn antenna. FIG. 12 is a sectional view taken along line AA of FIG. 11, FIG. 13 is a sectional view taken along line BB of FIG. 11, and FIG. 14 is a sectional view taken along line CC of FIG. FIG. 15 is a view showing a base end side of a cross section taken along line C-C of FIG. 12, and FIG. 16 is a side view of a still another embodiment of the water-cooled horn antenna viewed from the front end side. FIG. 17, FIG. 17 is a sectional view taken along line AA of FIG. 16, FIG. 18 is a sectional view taken along line BB of FIG.
19 is a diagram showing the distal end side of the cross section taken along the line CC of FIG. 17, FIG. 20 is a diagram showing the base end side of the cross section taken along the line CC of FIG. 17, and FIG. Side view of one embodiment of the antenna, FIG. 22 is a front view of the same embodiment, FIG. 23 is a cross-sectional view showing the structure of a primary radiator, FIG. 24 is a cross-sectional view showing the structure of a reflector, FIG. Is a block diagram showing a spacer, FIG. 26 is a side view of another embodiment of the water-cooled parabolic antenna, FIG. 27 is a front view of the same embodiment, and FIG. 28 is a block diagram showing one embodiment of the microwave radar. FIG. 29 is a waveform diagram for explaining the operation of FIG. 28, FIG. 30 is a configuration diagram of a 7-bit M-sequence signal generator, and FIG. 31 is a conventional in-furnace level meter applied to a smelting reduction furnace. FIG. 1 smelting reduction furnace, 6 slag, 12 microwave radar, 13 transmitting antenna, 14 receiving antenna, 15
… Waveguide, 16… antenna lifting device, 17… cable,
18 ... cable winding device, 19 ... motor, 21 ... antenna position measuring device, 24 ... signal processing circuit.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-38313 (JP, A) JP-A-60-90627 (JP, U) JP-A-52-9342 (JP, U)

Claims (9)

(57) [Claims] A microwave signal is output to a transmitting antenna having a transmitting antenna and a receiving antenna inserted into a furnace, reflected by a slag surface in the furnace, and received by the receiving antenna. A microwave radar that calculates the distance between these antennas and the slag surface and outputs it as a radar measurement signal, an antenna elevating device that elevates the transmitting and receiving antennas inserted into the furnace, and measures the antenna position, An antenna position measuring device that outputs an antenna position signal, and a slag level position in the furnace is calculated from a radar measurement signal of a microwave radar and an antenna position signal of the antenna position measuring device, and the slag level position in the furnace is determined. The set value or the upper set value and the lower set value are compared to calculate the amount of elevation of the antenna. Furnace level meter, characterized in that a signal processing unit for outputting to the antenna lifting device as descending control signal. 2. The transmitting and receiving antennas according to claim 1, wherein the whole inner side functions as a waveguide, and a metal inner pipe having a diameter-enlarging portion whose inner side functions as a horn antenna, and a metal outer pipe surrounding the inner pipe. A water-cooled horn antenna consisting of a tube and
Two cooling water passages that join the distal end of the enlarged diameter portion of the inner pipe and the distal end of the outer pipe, interpose a partition member almost entirely between the inner pipe and the outer pipe, and communicate with the distal ends of both pipes 2. A furnace level meter according to claim 1, wherein a cooling water supply port and a drain port are provided at a base end side of the cooling water passages. 3. The in-furnace level meter according to claim 2, wherein a gas purge port through which a purge gas flows is provided at a base end side of the inner pipe. 4. The first and second metal inner tubes each having a diameter-enlarging portion functioning as a horn antenna at an end of the transmitting and receiving antennas.
A water-cooled horn antenna comprising a metal outer tube surrounding the inner tube and a second inner tube, wherein the enlarged diameter portion at the tip of the first and second inner tubes and the tip of the outer tube are joined, and the inner tube and the outer tube are joined together. A partition member is interposed almost entirely between the pipes, and two cooling water passages communicating with each other at the distal ends of the two pipes are formed, and a cooling water supply port and a drain port are provided at the base end side of these cooling water paths. 2. The in-furnace level meter according to claim 1, wherein the level meter is provided. 5. The in-furnace level meter according to claim 4, wherein a gas purge for injecting a purge gas is provided at a base end of the first and second inner tubes. 6. The transmitting and receiving antenna is a water-cooled parabolic antenna comprising a primary radiator of a water-cooled structure and a reflector of a water-cooled structure having a parabolic surface facing an opening surface of the primary radiator. The in-furnace level meter according to claim 1, wherein 7. The in-furnace level meter according to claim 6, wherein the primary radiator comprises a waveguide and a feeder having a water-cooled structure having a double-tube or triple-tube structure. 8. The reflector includes a reflector having a parabolic surface facing an opening surface of the primary radiator, a back plate disposed on the back of the reflector, and a reflector interposed between the reflector and the back plate. 7. A cooling water passage is formed by joining outer peripheral portions of a reflection plate and a back plate, and a cooling water supply port and a drain port are provided on the back plate. Furnace level meter as described. 9. The in-furnace level meter according to claim 6, wherein the inner surfaces of the waveguide and the feeder of the primary radiator and the parabolic curved surface of the reflector are gas-purged.