JPH0672921B2 - Blast furnace charge profile meter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for measuring a level height distribution of a charge, that is, a profile of a charge in a blast furnace throat.

(Prior art and its problems) This kind of profile measuring device is shown in FIG.
While moving the lance B provided with a radar in the blast furnace, a microwave is projected onto the charging material C, and the distance between the surface of the charging material C and the lance B is measured at a plurality of points to measure the charging material. It measures the lu feeling.

Since the microwave reflectance of the blast furnace charge is low, it is difficult to measure the profile with high accuracy, and a method for checking the measurement data as shown in FIG. 7 has been proposed.

That is, as shown in Fig. 7, the full span from the reactor wall to the core is divided into several blocks, and the level change rate is calculated from the data obtained in block (ai).
+ ₁₎ of used to check the measured values.

The processing is performed with position data x ₁ , x ₂ ... x ₈ in the block ai and level
The rate of change is calculated from the data y ₁ , y ₂ ... y ₈ by the method of least squares according to the following equation.

Then y _n = _a m predicted using the result of the top-level from the current position data _{xn (x n -x n-a} ) + n-a and, in the range where there is a deviation by comparing the two In this case, the data representing the profile is output.

In the prior art, the level change rate is calculated from the level measurement result in front of a certain distance, and the current data is checked, which has the following problems.

(1) The data in the first block in the measurement cannot be checked, and the variations in the measured values remain (2) The data in the next section should be checked using the data in the above unchecked section (3) When the error of the level change rate in the section such as interference phenomenon becomes large, it affects other data.For the above reasons, the measurement accuracy may be deteriorated in the conventional technology. poor.

(Problems to be Solved by the Invention) The present invention has been made to solve the problem that the profile measurement accuracy is low in the conventional technique as described above. The purpose is to provide an obtained profile meter.

(Means for Solving Problems) The present invention relates to means for moving an FM radar above a charge in a blast furnace, means for detecting a measurement point position of the FM radar in the blast furnace, and beats obtained at each measurement point. In a blast furnace charge profile meter for detecting the profile of the charge in the blast furnace, which is provided with a distance calculation means for calculating the distance from the signal to the charge, a beat signal is input and the high frequency component of the beat signal is detected. High-pass filter to pass, low-pass filter to which beat signal is input, low-frequency component of beat signal is passed, amplitude of high-frequency component passed to high-pass filter and low-frequency passed to low-pass filter An amplitude ratio detection circuit for detecting the ratio of the component to the amplitude (high frequency component / low frequency component), and using the output from the distance calculation means in which the amplitude ratio is a predetermined threshold value or more, There is provided a charge profile meter blast furnace, characterized in that so as to obtain a profile of the object.

(Example) An example of the present invention will be described with reference to the drawings. FIG. 2 shows the device configuration of the present invention. This device comprises a lance 1 that can scan in the furnace radial direction, a driving device 2 for the lance 1, a microwave radar 3 mounted on the tip of the lance 1, and a signal processing device 4 for the microwave radar 3. The lance 1 can select an arbitrary measurement position in the furnace by moving the inside of the furnace 6 in the radial direction by the driving device 2. As shown in FIG. 4, by moving the lance 1 in the furnace 6, a plurality of measurement positions can be selected,
From this, it is possible to measure the level distribution of the charge.

FIG. 3 shows the configuration of the microwave radar. Radar 3
It is fixed to the tip of the lance 1 via the flange 3a. The radar is a jacket that houses a reflect horn antenna 8 that also serves to transmit and receive microwaves and a microwave circuit.
Composed of 10. In order to prevent dust in the furnace 6 from entering the antenna, a microwave window 9 for sealing the opening 8a of the antenna 8 in a dust-proof manner is provided. Microwave window 9
For example, quartz glass can be used. Further, in order to protect the microwave circuit from the high temperature in the furnace, the circuit portion is housed in a jacket 10, and the jacket 10 is a water cooling system using water sent through a water cooling pipe 11. Reference numeral 12 indicates a cable for transmitting and receiving electric signals relating to the microwave circuit part.

In FIG. 1, for example, the microwave oscillated from the microwave oscillator 13 using a Gunn diode is
The signal is transmitted from the antenna 8 via the stub tuner 15.
The microwave reflected from the input material and received by the antenna 8 again enters the mixing detector 16 through the stub tuner 15 and the demultiplexer 14. On the other hand, a part of the transmission wave reflected by the stub tuner 15 also enters the mixing detector 16. The mixed wave detector 16 mix-detects the transmitted wave and the received wave to generate a beat signal corresponding to the level height of the incoming material. The microwave oscillation frequency used in one example was 24.1 GHz, and the oscillation power was about 10
mW. 40 is a level height measuring unit. Mixed detector 16
The beat wave obtained from the above is applied to the mixer 41 of the level height measuring unit 40 via the amplifier 18. The mixed wave is mixed with a sine wave having a frequency f ₁ applied from the sine wave oscillator 45, and the mixed wave is passed through a high pass filter 42 to separate and output the upper sideband Wu of the mixed wave.

If the voltage waveform of the beat wave Wd is Eb and the output voltage waveform of the sine wave oscillator 45 is Er ₁ , then E _b = A _b sin (2πf _b t + φ _b ) (2) A _b : Beat signal voltage amplitude f _b : 〃 Center frequency φ _b : 〃 initial phase Er ₁ = A ₁ sin (2πf ₁ t + φ ₁ ) (3) The voltage waveform of the upper sideband Wu is (4)
It is represented by a formula.

E _u = A _u sin {2π (f _b + f ₁ ) t + φ ₁ + φ _b }
(4) The upper band wave Wu obtained as described above is applied to the mixer 43 and mixed with the sine wave having the frequency f ₂ applied from the sine wave oscillator 47, and this mixed wave is passed through the low pass filter 44. The lower sideband WL of this mixed wave is separated and output.

The output voltage waveform Er ₂ of the sine wave oscillator 47 is represented by Er ₂ = A ₂ sin (2πf ₂ t + φ ₂ ) (5).

Therefore, the voltage waveform of the lower sideband WL of the mixed wave is expressed by the equation (6).

E _L = A _L sin {2π (f _b + f ₁ −f ₂ ) t + φ _b + φ ₁ −φ ₂ } (6) A _L = kA _b A ₁ A _u k: conversion constant of mixer Here, T ₁ = 1 / (f ₁ −f ₂ ), φ ′ = φ _b + φ ₁
Replacing with −φ ₂ , the equation (6) is transformed into the following equation.

Comparing the equations (7) and (2), the lower band wave WL is obtained by linearly modulating the initial phase term in the original beat wave Wb with the period T ₁ .

The lower band wave WL shown by the formula (7) obtained by the low-pass filter 44 has its harmonics removed by the filter 48, and the waveform shaping circuit 49 further causes the zero crossing of the lower band wave WL represented by the formula (7). Produces a pulse corresponding to the point. Here, as an example, the zero cross point where the sideband rises from − to + is taken.

This pulse is applied to the counter 50, counted in the phase modulation period T _1, and the number of waves of the lower sideband is counted.

The counting result ΣN of the counter 50 is applied to the distance calculation circuit 51, and the frequency of the frequency modulation period T ₂ of the transmission wave WS per cycle is
The number n of waves of the lower side band WL is calculated by the equation (8), and further the distance d to the object to be measured is calculated based on the equation (9).

n = ΣN / m (8) m = T ₁ / T ₂ T ₁ : Phase modulation period T ₂ : Frequency modulation period d = n × c / 8 ΔF (9) ΔF: FM maximum frequency deviation of transmitted wave WS Transition c: The speed of light 60 is an amplitude ratio measurement circuit that measures the amplitude ratio of the high frequency component and the low frequency component of the beat signal, and includes the following circuit. The amplified beat signal is separated into a high frequency component and a low frequency component of the beat signal by a high pass filter 61 and a low pass filter 62, respectively.

Each component has an absolute value calculation circuit 63, 64 and an average value calculation circuit 65, 66.
Then, the average amplitude is obtained. Both are input to the divider 67, and the ratio is compared with the constant k by the comparator 68.
The result is input to the distance calculation circuit 51, and when the amplitude ratio is large, the distance data is output.

The lance 1 is moved to a plurality of predetermined positions in the blast furnace by using the above-described apparatus, the level of the charged material is measured at each position, and the level is obtained from the distance calculation circuit 51 and the level is measured at each position. Plot the level of input. This gives a profile of the charge. FIG. 6 is a plot of measurement data obtained by a conventional profile meter, and the measurement data varies considerably due to the interference effect of microwaves due to the charge.

On the other hand, FIG. 5 shows the result of an experiment using the apparatus of the present invention, in which an amplitude ratio of a high frequency component of a beat signal to a low frequency component is obtained, and a circuit for removing data whose ratio is smaller than a certain threshold value is provided. According to the present invention, it was confirmed that the variation was smaller than that of FIG. 6 and the effect of error reduction was remarkable.

(Effect of the Invention) As described in detail above, according to the present invention, when measuring the profile of the charge of the blast furnace by the range finder using the FM radar, the high frequency component of the beat wave and the amplitude of the low frequency component are compared with each other. Since the ratio is obtained and the data having the predetermined value or more is used as the data representing the profile, (1) all the distance measurement data are checked by the frequency spectrum distribution of the beat signal within the measurement time.

(2) The ratio of the high frequency component to the low frequency component is calculated and the check is performed by using it. Therefore, even if the unwanted reflected wave in the radar circuit changes due to the adhesion of dust in the blast furnace to the radar antenna part, the reliability is improved. High measurement is possible and maintainability is improved. As a result, accurate profile data with little variation can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the profile meter of the present invention, FIG. 2 is a front view showing the configuration of an FM radar measuring apparatus to which the profile meter of FIG. 1 is applied, and FIG. 3 is an FM radar section. 4 is a sectional view showing the measurement method of the device of the present invention, FIG. 5 is a graph showing the measurement results obtained by the profile meter of the present invention, and FIG. 6 is a conventional profile meter. Fig. 7 is a graph showing the obtained measurement results, and Fig. 7 is a view showing a method for measuring the level height of the blast furnace charge by the FM radar. 1 ... lance, 8 ... antenna, 16 ... mixed detector, 40
...... Level height detection circuit, 51 …… Distance calculation circuit, 61 …… High-pass filter, 62 ……
Low pass filter, 67 …… divider, 68 …… comparator.

Claims (1)

[Claims] 1. A means for moving an FM radar above a charge in a blast furnace, a means for detecting a measurement point position of the FM radar in the blast furnace, and a beat signal obtained at each measurement point to a charge. In a blast furnace charge profile meter that detects the profile of the charge in the blast furnace, equipped with a distance calculation means that calculates the distance, and a high-pass filter that receives the beat signal and passes the high-frequency component of the beat signal. , The ratio of the amplitude of the high-frequency component passing through the high-pass filter to the amplitude of the low-frequency component passing through the low-pass filter, and the low-pass filter that receives the beat signal and passes the low-frequency component of the beat signal ( An amplitude ratio detection circuit for detecting a high frequency component / a low frequency component), and using the output from the distance calculation means having the amplitude ratio of a predetermined threshold value or more, the profile of the charge is obtained. A blast furnace charging profile meter characterized by the above.