JPH03281717A - Method and instrumetn for measuring slag level in converter - Google Patents

Abstract

PURPOSE:To execute the exchange of a sub-lance and an antenna in a short time by enabling inserting of the sub-lance and the antenna for slag level meter through a common hole arranged in a hood in a converter. CONSTITUTION:The antennas 17, 18 connecting a microwave radar type slag level meter 16 are supported to a beam 20 as liftable and rotatable through a lifting device 22, hinge 21 and rotating device 23. Further, the sub-lance 7 is also supported as liftable and rotatable to the beam 20 through a lifting device 22a, hinge 21a and rotating device 23a. By this constitution, over the period from molten slag developing stage to a stage when the decarbonizing is most marked in converter blowing, the antennas 17, 18 from the hole 25 arranged to the hood 5 are inserted into the converter 1, and by measuring the slag level, prediction of slopping is executed. Successively, in the low carbon period, the sub-lance 7 is inserted into the converter 4 from the hole 25, and temp. measurement and sampling in molten steel 2 are executed. By this method, the exchange of antennas 17, 18 and sub-lance 7b is executed in a short time and the converter refining is efficiently executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for a slag level meter 7Ipj in a converter for predicting the occurrence of slopping during converter refining.

[Prior Art] During refining in a converter, slag floating on the surface of molten steel in the converter forms depending on conditions such as the composition and viscosity of the slag, and the amount of oxygen in the slag. When such slag forming progresses excessively, so-called slopping occurs, which adversely affects the molten steel composition, the total tapping yield, and the like. Furthermore, when slopping occurs, problems such as a decrease in work efficiency, a decrease in calories in exhaust gas, deterioration of the work environment such as generation of red smoke, and damage to equipment occur.

On the other hand, from the viewpoint of preventing slag slopping, it is possible to introduce a slag foaming inhibitor or to reduce the amount of lance oxygen supply as a measure to reduce the amount of exhaust gas generated. Excessive use of slag forming agent increases costs and decreases thermal efficiency due to a decrease in furnace temperature. On the other hand, reducing the amount of oxygen sent causes longer operating time due to a decrease in reaction efficiency, which leads to a decrease in productivity. Become.

Therefore, to prevent slopping from occurring,
In addition to simply predicting slopping, it is necessary to quantitatively and accurately grasp the level of slag in the converter in order to operate the converter appropriately.

For this reason, a technology to quantitatively measure the slag level in the converter has been considered, and the conventional technology uses microwaves that propagate straight even under measurement environmental conditions in the converter where dust and flames exist. Radar-based level meters using

An example of a conventional slag level meter using a microwave radar system is disclosed in Japanese Patent Laid-Open No. 83-21584. Figure 6 is an explanatory diagram of this invention, in which (1) is the converter furnace body, (2) is the molten steel, (3) is the slag, (4) is the flue, (5) is the hood, and (6) is the lance. It is. In this converter, microwave FM with a carrier frequency of about 10 GHz is used.
The antenna (12) of the cW radar (11) is fixed above the converter body (1), and microwaves are transmitted toward the surface of the slag (3), and this signal is transmitted to the surface of the slag (3). The round-trip propagation time until it is reflected by the antenna (12) and received again by the antenna (12) is l fl? I and convert it into distance.

In addition, the patent application filed by the applicant of the present invention 1986-250
No. 784, as shown in Figure 7, the reflectance of the surface of the formed slag (3) to microwaves is small, and in order to improve the problem that the sensitivity of the FMCW radar described above is insufficient, the carrier wave Microwave pseudo-random signal processing radar (13
), the water-cooled antenna (15) is attached to the tip of the water-cooled waveguide (14) from above the converter, inserted into the converter, and the microwaves are transmitted toward the surface of the slag (3). ,
The round-trip propagation time for this signal to be reflected on the surface of the slug (3) and received again by the water-cooled antenna (15) is calculated n.
A device has been proposed to convert this into distance.

[Problem to be solved by the invention] In all of the above conventional technologies, the antenna (12)
, (15), it is necessary to secure a place to fix the antenna or a dedicated hole for inserting the antenna in the hood (5) above the converter. However, carrying out construction work to attach the antenna to the hood (5) is difficult because the incidental equipment of the converter, such as the main lance, sub-lance, auxiliary material input hopper and duct, are installed in a high density, so it is difficult to compete for space. It is complicated and causes an increase in capital investment costs. In particular, when modifying an existing converter and installing an antenna, or when recently boiler piping has been installed in the hood (5) as an energy saving measure by recovering exhaust heat, the cost of modifying the hood is extremely high. The problem is that it gets expensive.

This invention was made to solve the above-mentioned problems, and therefore, the sub-lance insertion hole for inserting into the converter in the latter stage of converter blowing and the antenna insertion hole are shared.
An object of the present invention is to obtain a method and device for a slag level meter in a converter-I11, which allows the use of an antenna and a sublance alternately during the blowing period of the converter.

[Means for Solving the Problems] The slag level meter iip+ method in a converter according to the present invention connects a sublance and a water-cooled antenna to which a microwave radar type slag level meter is connected from both sides of the converter. be interchangeable so that either one is inserted into the converter,
During the early and middle stages of converter blowing, a water-cooled antenna was inserted into the converter to maintain a slag level of 81 dFI, and during the latter stages of blowing,
The sublance is inserted into the converter.

Further, the slag level meter 711 device in a converter according to the present invention includes a sub-lance and a water-cooled antenna that are rotatably and vertically attached to a beam above the converter, and a microwave radar system connected to the water-cooled antenna. The sub-lance and water-cooled antenna can be interchanged in position, and either one can be inserted into the converter through a common hole in the converter hood.

Furthermore, the microwave radar type slag level meter in the above method and apparatus transmits a microwave modulated with a pseudo-random signal, receives a reflected wave from the slag surface, and measures the round trip propagation time of this microwave. This is converted into distance.

[Function] The sublance is inserted into the converter to measure the temperature of molten steel.
Obtain samples of molten steel, slag, etc.

A slag level meter, which consists of a water-cooled antenna and a microwave radar, transmits microwaves from the antenna, receives the reflected waves that are reflected back from the slag surface, and takes the round-trip propagation time of the microwaves. The slag level is measured by taking into account the propagation speed of microwaves in the air and converting it into distance.

The sub-lance and water-cooled antenna are each attached to the beam so that they can be rotated and moved up and down, so by rotating them, their respective positions can be changed in a short time, and if necessary, the sub-lance or water-cooled antenna can be attached to the converter. It can be inserted inside.

Therefore, during the early and middle stages of converter blowing, when slopping is relatively likely to occur, a water-cooled antenna is inserted into the converter to measure the slag level and predict slopping.

On the other hand, in the later stages of blowing when the slag level is low and stable, slopping does not occur, but it is necessary to obtain information such as the composition and temperature of the molten steel, so a sub-lance is inserted into the converter to measure the molten steel temperature. Perform sampling.

[Embodiment of the Invention] FIG. 1(a) is a schematic cross-sectional view of an embodiment of the present invention, and FIG. 1(b) is a plan view thereof.

In the figure, (1) is the converter furnace body, (2) is the molten steel, and (3) is the converter body.
is the slag, (4) is the flue, (5) is the hood, (24) is the boiler piping installed on the inner wall of the hood (5) for exhaust heat recovery, (6) is the lance, Hole (2)
6) into the converter. (16) is a microwave pseudo-random signal processing radar type slag level meter (hereinafter referred to as slag level meter), which is connected to the transmitting antenna (17) and receiving antenna (18) via the waveguide (14). , these antennas are inserted into the converter through holes (25) in the hood (5) and measure the level of slag (3) in the converter.

The waveguide (1) to which the antenna (17) and 18) are attached
4) can be raised and lowered by an elevator (22) using an electric motor, and a rotating device (23) using a hinge (21) and an electric motor.
It can be rotated by (20) is a beam, and the rotating device (23)
and supports the hinge (21). Sublance (7) also
A hole (25) made in the hood (5) by the lifting device (22a), hinge (21a), and rotating device (23a)
Through this, it is possible to insert into the furnace and withdraw from the furnace.

As mentioned above, either the antennas (17), (18) or the sub-lance (7) can be inserted into the furnace, and these can be replaced in a short time.

The reflectivity of the formed slag to microwaves is extremely small, 10<-4> or less, so a conventional FMCW microwave radar cannot provide sufficient sensitivity, and a highly sensitive microwave radar is required. Therefore, in the present invention, a radar with increased sensitivity is used by using a pseudo-random signal based on microwave signals. The configuration of the slag level meter is shown in Figure 2. This is the distance i11! proposed in the aforementioned Japanese Patent Application No. 63-250784! 1
It is based on the same technical idea as the 111 method and its device.

In FIG. 2, (31) is a carrier wave oscillator, (32) is a distributor, (33) is a multiplier, (34) is a transmitter, and (35) is a multiplier.
) is a hybrid combiner, (3G), (37) is a clock generator, (38), (39) are pseudorandom signal generators, (4o) is a multiplier, (41) is a low-pass filter, (42) is Receiver, (43) is a multiplier, (44)
is a divider, (45), (411i) is a multiplier, (47
), (4g) is a low-pass filter, (49),
(50) is a squarer, (51) is an adder, (52) is a time 71-1 constant, and (53) is a distance converter.

FIG. 3 is a waveform diagram for explaining the operation of FIG. 2, and FIG. 4 is a configuration diagram of a 7-bit i M sequence signal generator.
5) is a seven-stage shift register, and (56) is an exclusive OR circuit.

Next, the operation of the slag level meter (16) shown in FIG. 2 will be explained with reference to FIGS. 3 and 4. For example, an M-sequence signal generator can be used as the pseudo-random signal generators (38) and (39). Figure 4 shows the configuration of a 7-bit M-series signal generator.
It is composed of a seven-stage shift register composed of (logic) elements and an exclusive OR circuit (56). The M-series signal has the sign “]° (corresponds to positive voltage +E) and “0゛
(corresponding to the negative voltage -E), and in the case of 7 bits in this embodiment, 21. -127 pieces (1
One cycle is completed when a signal of 27 chips (also referred to as 27 chips) is generated, and a circulating signal that repeats this cycle is generated. Since the pseudo-random signal generators (38) and (39) are constructed of the same circuit, their output signals have exactly the same pattern. However, since the supplied clock frequencies are slightly different, the one cycle is also slightly different. In addition to pseudorandom signals and M-sequence signals, gold-series signals and JPL-series signals can also be used.

The clock generators (3B) and (37) both have a built-in crystal oscillator and generate clock signals with sufficiently stable frequencies, but the generated frequencies are slightly different.

In this embodiment, the frequency fl of the clock generator (36) is
is ioo, 004 MHz, the generation frequency f2 of the clock generator (37) is 99.996 Ml1z and 17, and the frequency difference is flf 2-8 kllz. Clock signals f 1 and f2 output from clock generators (36) and (37), respectively, are supplied to pseudorandom signal generators (38) and (39), respectively. Pseudo-random signal generators (38) and (39) output M-sequence signals M and M2 having the same pattern, although each period is slightly different due to the frequency difference of the driving clock signal. Now finding the period of the two M-sequence signals M and M2, we get the period of M - 127x l/100.004 Ml1z'
i 12G9.9492nsM2 period - 127x 1
/ 99.996MHz'':, 1270.05080S
becomes. That is, the two M-sequence signals M and M2 are approximately 127
It has a period of 0ns (1o-9 seconds), but the period of both is about 0. There is a time difference of ins. Therefore, if these two M-sequence signals M and M2 are generated cyclically, and the patterns of the two M-sequence signals match at a certain time t, 0. A deviation of Ins occurs between both signals, and after 100 cycles, a deviation of 1 ns occurs between both signals. Here, the M-sequence signal is 1 in one period of 1270 ns.
Since 27 signals are generated, the generation time for one signal is 1O
It is ns. Therefore, the difference in Ions between the two M-sequence signals M and M2 means that the M-sequence signal is 1
This corresponds to being shifted by an individual amount.

The output M1 of the pseudorandom signal generator (38) is sent to the multiplier (
40) and (33), and a pseudorandom signal generator (
The output M2 of 39) is supplied to multipliers (40) and (43), respectively.

A carrier wave generator (31) oscillates a microwave with a frequency of about 17 Gllz, for example, and its output signal is distributed by a distributor (32) and supplied to a multiplier (33) and a hybrid combiner (35). The multiplier (33) is composed of, for example, a double-balanced mixer, and receives a carrier wave with a frequency of approximately 17G) Iz inputted from the distributor (32) and an M-sequence signal M1 inputted from the pseudorandom signal generator (38).
The carrier wave is phase-modulated and a spread spectrum signal is output, which is supplied to the transmitter (34). The transmitter (34) power amplifies the input spread spectrum signal, converts it into electromagnetic waves via the transmitting antenna (17), and radiates the electromagnetic waves into the converter (1).

Here, the wavelength of electromagnetic waves with a frequency of 17 Gtlz in the air is approximately 1.8 cm, which is sufficiently long compared to the particles of dust and smoke in the converter (1), so it is not easily affected by dust, etc., and the wavelength is approximately 1.8 cm. Since it is short, it is advantageous for downsizing the antenna. Further, the transmitting antenna (17) and the receiving antenna (18) are made of bone antennas, for example, and the directivity is sharply narrowed to minimize the reflected power from sources other than the slag.

Note that the antenna gain is, for example, about 20 dB in each case.

The electromagnetic waves radiated from the transmitting antenna (17) toward the inside of the converter (1) are reflected by the slag and transmitted to the receiving antenna (18).
) is converted into an electrical signal and input to the receiver (42). The timing at which the input signal is supplied to the receiver (42) is, of course, from the timing at which the electromagnetic waves are radiated from the transmitting antenna (17), the electromagnetic waves travel back and forth to the slag level in the converter (1), and then to the receiving antenna. (18) is delayed by the electromagnetic wave propagation time. Receiver (
42) amplifies the input signal and supplies it to the multiplier (43).

On the other hand, the multiplier (40) is connected to a pseudo random signal generator (38
) and (39) respectively.
and M2 are multiplied, and the time-series signal of the multiplied value is supplied to the low-pass filter <41). (A) in Fig. 3 is the input signal to this low-pass filter (41),
In other words, it is a waveform showing a time-series signal that is the multiplication value of the multiplier (40), and when the phases of the two pseudo-random signals input to the multiplier (40) match, the output voltage of +E is Continuing, if the phases of both signals do not match, +E and -E output voltages are randomly generated.

Low pass filter (41), (47), (4g
) has a kind of integration function by limiting the frequency band, and when the phases of both signals match as an integral signal of the correlation calculation value of both signals, the signal shown in (a) in Figure 3 is obtained. Outputs a unique pulse-like signal. Further, when the phases of both signals do not match, the output becomes zero. Therefore, a pulse-like signal is periodically generated at the output of the low-pass filter (41). This pulsed signal is supplied to the time measuring device (52) as a time reference signal. In this embodiment, the period TB of this reference signal is such that the pseudo-random signal is combined with the 7-bit M-sequence signals M1 and M2 and 1. Therefore, the wave number N in one period is 27-
1-127, f l-100,004M1lzS
Since f 2−99.996Ml1z, T o −
It will be 15-875m5. This reference signal and its period TB
is shown in (1) of FIG.

Further, the received signal from the receiver (42) and the M-sequence signal M2 from the pseudo-random signal generator (39) are input to the multiplier (43), and the two signals are multiplied.

The multiplication result of this multiplier (43) is the first M-sequence signal M
If the modulated phase of the received signal whose transmission carrier wave is phase-modulated by 1 matches the phase of the second M-sequence signal M2, the modulated phase of the received signal is output as a phase-aligned carrier signal. When the phases of M-sequence signal M2 and
44).

The distributor (44) divides the input signal into two, and supplies the divided outputs R and R2 to the multipliers (45) and (46), respectively. The hybrid combiner (35), to which a part of the transmission carrier wave is supplied from the distributor (32), receives a signal component of the in-phase component (with a phase of 0 degrees) and a signal component of the quadrature component (with a phase of 90 degrees) with respect to the input signal. ) signals Q and are supplied to multipliers (45) and (46), respectively. Multiplier (45
) is the signal 1 input from the hybrid coupler (35)
(i.e. a signal in phase with the output of the carrier wave oscillator (31)),
The multiplier (46) multiplies the signal R1 input from the divider (44) by p, and the multiplier (46) similarly receives the input signal Q (i.e., a signal with a phase difference of 90 degrees from the output of the carrier wave oscillator (31)).
is multiplied by the signal R2, and the phase O variation component (■・R,) and the phase 90 degree component (Q-R,) are obtained in the received signal, respectively.
2) and output as a test wave signal. Signals 1-R and Q-R2 as the test wave signals are supplied to low-pass filters (47) and (48), respectively.

The low-pass filters (47) and (48) have an integration function by limiting the frequency band, and integrate the correlation calculation values of the two signals. That is, the signal R1 is input from the output of the multiplier (43) to the multiplier (45) via the distributor (44), and the signal I is input from the hybrid combiner (35) to the multiplier (45). When the phases match,
Similarly, the signal R2 and the signal Q input to the multiplier (46)
When the phases of the multipliers (45) and (46) match, the output signals of the multipliers (45) and (46) become pulse signals of constant polarity (pulse signals of voltage 1E), and the low-pass filters (47) and (48) integrate this signal. A large positive voltage is obtained at the output. Further, when the phases of the signal R1 and the signal I do not match, and when the phases of the signal R2 and the signal Q do not match, the output signals of the multipliers (45) and (46) each have a positive and negative polarity that changes randomly. pulse signal (i.e. voltage +
E and -H pulse signals), and the outputs of the low-pass filters (47) and (48) that integrate these signals become zero.

The phase 0 signal component and the phase 90 degree component signal processed by the low-pass filters (47) and (48) by <vi as described above are supplied to square generators (49) and (50), respectively. Squarers (49) and (50) each square the amplitude 11 of the human input signal, and supply the output signal of the calculation result to the adder (51). The adder (51) adds the two human force signals and outputs a pulsed detection force signal as shown in (1) in FIG. 3, which is supplied to the time measuring device (52).

Let us now assume that the time at which the maximum value of this detection signal occurs is t.

In this way, the phase 0 variation component and the phase 90 degree component of the transmission carrier wave are detected from the signal obtained by the correlation processing between the received signal and the M-sequence signal M2, and each of the detected wave signals is subjected to integration processing and square calculation. However, although this method of obtaining a slug level detection signal as the sum of a pair of square values has a somewhat complicated structure, it is possible to obtain a highly sensitive slug level detection signal. In addition, since we are trying to obtain a correlated output of a pseudorandom signal such as an M-sequence signal, we use a slug level measuring device with a high signal-to-noise ratio (S/N) to reduce the influence of noise and emphasize the signal. It can be realized. Of course, as a carrier wave detection method, there is a detection method using a crystal, and although the sensitivity is lowered, the configuration is simplified, so this method can be adopted depending on the specifications and cost.

The time 7I-] regulator (52) determines the generation time t of the maximum value of the reference signal input from the low-pass filter and the adder (52).
1) Measure the time TD between the maximum value of the detection signal input from time t and the time t. Therefore, the time measuring device (52) has a function of detecting the time when the maximum value of the two input signals occurs. For example, by sequentially sampling and holding the input voltage value using a clock signal, and successively comparing the sample value based on the current clock signal and the previous sample value of the clock signal using a voltage ratio device, the input voltage value is increased over time. By detecting the time when the state reverses to the decreasing state, it is possible to detect the time when the maximum value of the input signal occurs. The time T is shown as the time between the maximum value occurrence time t of the reference signal shown in FIG. 3(1) and the maximum value occurrence time t of the detection signal shown in (1). During this time T, the electromagnetic waves are actually transmitted and the transmitting antenna (17
) and (18) of the propagation time τ to travel the distance between the surface of the slug and the surface of the slug, f,/(f.

f2) is temporally expanded by a factor of 2. In the case of this example, f 1-100.004 MIIz, f 2-9
Since it is 9.996 MIIZ, the time is expanded by 12.500 times, and the following equation is obtained.

TD -12,5QOτ
...[1] Note that the time T in the [1] equation is obtained every cycle TU3 of the reference signal.

In this way, since the measurement time of the present invention is greatly expanded, the slag level in the converter (1) can be accurately measured flPj from a short distance.

Therefore transmitting and receiving antennas (17), (18)
The distance #lx meters from the slag surface in the converter (1) to the slag surface in the converter (1) is determined by the following equation.

x − (f − f ) /2f・v・TDl
2 1 -1.2 XIO' ・T , ...[2] The transmitting antenna (17) and the receiving antenna (18) can be used in common, but in this example, interference in the signal system is reduced. A separate antenna was installed for this purpose. Each antenna is a small antenna with a diameter of 100mm, and can be accessed through a small hole with a diameter of 270mm provided in the hood (5).

This slag level meter was able to measure the slag level in the converter with an accuracy of 100111 and a response speed of 3 seconds.

Next, as shown in Fig. 5, sublance (7) and antenna (17)
), (18) will be described below. First, from ignition to the slag period and the peak decarburization period,
Antenna (17), (+8) of slag level meter (16)
Insert it into the converter and check the slag level +111JL,
Predict slopping. During the subsequent low coal period, the sublance (7) is inserted into the furnace, and the temperature of molten steel = -1Δ
p1, sampling is performed. That is, about 6 minutes after ignition
There is a risk of slopping due to abnormal reactions between the slags and slags, and there is a risk of slopping as the slag level becomes relatively high during the peak decarburization period. So what is the slag level? l-, (#J) When the slag level rises rapidly or when the slag level is higher than a predetermined level, a foaming inhibitor such as coke powder or limestone is introduced into the furnace. Approximately 1 from ignition
After 1 minute, the refining enters the low coal stage, the slag level is low and stable, and there is no risk of slopping. However, in the later stages of refining, it is necessary to measure the temperature of the molten steel and zumbling to adjust the composition of the molten steel. , insert the sub-lance (7) into the furnace.

In the embodiment described above, the slopping rate, which was previously about 9%, was able to be reduced to 1% or less.

[Effects of the Invention] As explained above, according to this invention, the sublance and the antenna of the slag level meter can be inserted and exchanged in a short time through a common hole provided in the hood of the converter. , equipment is easy to install, and in particular, it is easy to modify and install an existing converter.

In addition, by measuring the slag level in the converter by 11-1 during periods when slopping is likely, the condition of the slag can be accurately grasped and the occurrence of sloping can be accurately predicted, thereby suppressing slopping. Measures can prevent slopping. As a result, efficient converter refining can be achieved.

[Brief explanation of the drawing]

FIG. 1(a) is a cross-sectional view schematically showing an embodiment of the present invention, (1)) is a plan view thereof, and FIG. 2 is a block diagram showing the configuration of a slag level meter which is the main part of the present invention. Figure 3 is a waveform diagram to explain its operation, Figure 4 is a configuration diagram of a 7-bit M-sequence signal generator, and Figure 5 is a diagram to explain the application period of the slag level meter in this invention. The diagram, FIGS. 6 and 7 are schematic diagrams for explaining the prior art. (1)...Converter body, (3)...Slag, (6)...
...Lance, (7)...Sub Lance, (16)...
Slag level meter, (17), (1g)...antenna,
(20)... Beam, (25)... Hole.

Claims (3)

[Claims] (1) From above the converter, the sublance and the antenna connected to the microwave radar type slag level meter are made interchangeable so that either one can be inserted into the converter during the first half of the converter blowing process. A method for measuring a slag level in a converter, characterized in that the antenna is inserted into the converter in the middle stage of blowing to measure the slag level, and the sublance is inserted into the converter in the latter stage of blowing. (2) It consists of a sublance and an antenna that are rotatably and vertically attached to a beam above the converter, and a microwave radar type slag level meter connected to this antenna, and the location of the sublance and antenna is 1. A slag level measuring device in a converter, characterized in that the slag level measuring device in a converter is configured such that either of the two can be replaced and either one can be inserted into the converter through a common hole in the hood of the converter. (3) A microwave radar type slag level meter transmits microwaves modulated with a pseudo-random signal, receives reflected waves from the slag surface, measures the round-trip propagation time of this microwave, and converts this into distance. The method for measuring a slag level in a converter according to claim (1), or the device for measuring a slag level in a converter according to claim (2), which is a level meter configured to do the following.