JPS6212819A - Method and device for weighing raw material in furnace top charging device - Google Patents

Abstract

PURPOSE:To scale the raw material inside a bunker correctly by performing the arithmetic processing of the raw material weight pre-measured prior to the input inside the bunker and the total weight of the bunker measured by the bunker scale of a load cell, etc. CONSTITUTION:The output of the load cell 14 measuring the dead weight of a bunker 3 shows time lapse variation. Load cells 15, 16 weigh the raw material inside the bunker 3 with good accuracy in advance. An arithmetic processing unit 17 stores by finding the relation of the output and load of the load cell 14 at point A- point D by processing the data transmitted from the load cells 14-16. The data concerning the point A- point D are statistically processed by least square approximation, etc. extending over several times in the past, the load cell characteristics are divided into the load increase time (point A- point B) and load decrease time (point C- point D) and the reference approximate curve thereof is found. The unit 17 then converts the output of the load cell 14 into a load by using the reference approximate curve thus found. The error on the nonlinearity in the load cell characteristics and the fluctuation of the origin A and variation in the output due to the hysteresis and temp. variation is eliminated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention allows the interior of the bunker to change from an empty state to an atmospheric pressure state when raw materials have been input, and then to a pressurized state equal to the furnace internal pressure. Raw materials are charged into the furnace, and a bunker is installed at the top of the furnace that is brought to atmospheric pressure after the inside is emptied. The present invention relates to a raw material weighing method for a furnace top charging device that weighs raw materials in a furnace, and an apparatus for carrying out the method.

[Prior Art] Generally, in a raw material weighing device for knee seeds, a load cell is used as a bunker weighing device to measure the total weight of the bunker at the top of the furnace.

FIG. 5 shows the change over time in the output of the bunker load cell as the top charging device operates. In the figure, point A is the bunker's own weight, points 81 and B2 are the weight of the bunker's own weight plus the weight of the raw material, and points C1 and C3 are the weight of the bunker's own weight plus the weight of the raw material and the lifting force due to the internal pressure of the bunker is subtracted. 1o, point and 2 points respectively mean the weight obtained by subtracting the lifting force due to the internal pressure of the bunker from the bunker ff1fit.

First, point A when there is no raw material in the bunker and under atmospheric pressure is set as the origin, and when raw material is introduced into the bunker, it moves from point A to point 88. In other words, the output of the load cell increases in accordance with the amount of raw material input. Then, when the inside of the bunker is pressurized from the 83rd point, a lifting force acts on the bunker due to the internal pressure, and the output of the load cell decreases by that amount. At point C3, the pressure inside the bunker becomes equal to that inside the furnace. Then, when the raw material in the bunker is charged into the furnace from the time of point C1, the output of the load cell gradually decreases, and after the charging of the raw material is finished, it reaches point B1. Then, when the pressure inside the bunker is evacuated to the original atmospheric pressure from point 03, the lifting force acting on the bunker disappears, and the output of the load cell increases accordingly, returning to the original point A again. Therefore, in the range of Sl, the inside of the bunker is at atmospheric pressure, and S,...
Within this range, the inside of the bunker is under the same pressure as the inside of the furnace.

In this way, the load cell sequentially measures the total weight of the bunker, and the raw material weighing device determines the raw material in the bunker based on the measured value.

Conventionally, the output of such a load cell as a bunker weighing device has been treated as something that changes linearly depending on the load of the bunker weight. That is, as shown in FIG. 6, on a coordinate system in which the output of the load cell is plotted on the vertical axis and the load is plotted on the horizontal axis, a straight line connecting point A and two points is defined as the output characteristic of the load cell. Point A is the point when there is no raw material in the bunker and the pressure is at atmospheric pressure, as in the case of FIG. 5, and serves as the origin. The second point is the point when the load is 100%.

In this way, in the past, the output characteristics of a bunker weigher were linear, and the output was simply manipulated to perform weighing.

[Problems to be Solved by the Invention] Conventionally, the characteristics of a load cell used as a bunker weigher have been simply treated as linear, resulting in the following problems.

When weighing coke and ore, which have a weight ratio of 3 to 4 times, a large-capacity load cell that can handle the maximum weight of the bunker's own weight plus the total weight of the charged raw materials is required, and in practice A load cell with a large capacity relative to the weight of the raw material to be measured is used, which increases the measurement error. This was particularly noticeable when measuring the weight of coke, which has a low specific gravity. In addition, when the inside of the bunker is pressurized to the same pressure as the inside pressure of the furnace and maintained on the positive side with respect to atmospheric pressure while raw materials are being charged into the furnace, the upward lifting force generated against the bunker causes the load cell to Since the load on the hanger is reduced, the measurement error of the load cell itself is added to the correction error of the lifting force, making it difficult to accurately weigh the raw material during charging as it decreases. In particular, it was impossible to weigh the raw material when the inner bunker m was small.

Moreover, in the past, the detection characteristics of the load cell were treated as linear, but this was different from the original characteristics of the load cell, resulting in an even larger detection error.

That is, the load cell itself has the following three typical characteristics that cause detection errors. The first reason is due to the non-linearity of the load cell characteristics as shown in FIG. 7, in which a deviation δ1 occurs in the output when 0 to 160% points are connected with a straight line. The deviation δ1
is generally expressed as the deviation from 50% load when the load increases.

The second reason is due to hysteresis in the load cell characteristics, and as shown in FIG. 7, a deviation δ occurs when the output increases and decreases at 50% load. The third reason is due to the repetition error of the load cell frame column, and as shown in FIG. 8, a deviation δ occurs when a load is repeatedly applied under the same load conditions.

However, conventionally, the characteristics of a load cell that essentially draws curves as shown in FIGS. 7 and 8 are approximated as those that draw a straight line as shown in FIG. 6. Therefore, a large detection error occurs.

FIG. 6 shows both the detection characteristics inherent to the load cell and the straightness. So, based on this diagram.

This section explains the current state of measurement errors.

First, on the essential characteristic curve of the load cell,
When a raw material is introduced into the bunker from a point A under atmospheric pressure with no raw material in the bunker, it moves on a curve and reaches point B. After the charging of raw materials is completed, the pressure in the bunker is increased to equalize the pressure in the furnace, and the pressure in the bunker acts on the bunker to lift it, causing it to move to the zero point on the characteristic curve.

Then, while the raw material is being charged into the furnace, it moves on the characteristic curve toward the point, and after the raw material is loaded, it reaches point D.

Currently, the detection signal on the essential characteristic curve of such a load cell is approximated as being on a straight line. Therefore, at points B and C, the actual weight is measured to be larger by wb and wc, respectively, and at point D, it is smaller by wd, which results in an error. Such errors pose a particularly serious problem when it is detected that the entire amount of raw material in the bunker has been charged. In other words, if the influence of the lifting force due to the equal pressure inside the bunker is constant (62 m), 8 straight up points can be found, but if we assume that the output is constant and extend it to find 2 points, we can find the actual installation. If there is a point before the charging completion point D, charging will be completed at the point. Therefore, it is necessary to detect the completion of charging by other means, or to start the next operation after allowing sufficient time, which is a factor that lengthens the time cycle of the entire charging device.

This invention solves the above problems.

[Means for resolving the problem once and for all] The raw material weighing method of the furnace top charging device of the present invention is such that the inside of the bunker changes from an empty state to an atmospheric pressure state when the raw material has been charged, and then pressurizes it equal to the furnace internal pressure. A bunker is installed at the top of the furnace, and the raw materials inside the furnace are charged into the furnace after the condition is reached, and the bunker is brought to atmospheric pressure after the inside is emptied. In a raw material weighing method for a furnace top charging device that weighs raw material in a bunker using
The output of the bunker scale when the bunker is empty and at atmospheric pressure is stored as a reference point, and the output of the bunker scale when the bunker is empty and at atmospheric pressure is stored as the reference point. It is stored as a load corresponding to the load at atmospheric pressure plus the pre-weighed weight of the raw material charged into the bunker, and the bunker weight at pressurized state when the raw material has been loaded into the bunker. The output of the container is stored as the load obtained by subtracting the bunker lifting force due to pressurization inside the bunker from the load at atmospheric pressure when the raw material has been input into the bunker, and the raw material inside the bunker is The output of the bunker weigher when the bunker is empty and pressurized after being fed into the furnace is the load that will be in the pressurized state when the material has been completely fed into the bunker. It is stored as a load corresponding to the weight of the raw material charged,
Then, by statistically processing these stored data, a relational expression between the output of the weigher and the load is determined, and the raw material in the bunker is weighed based on the relational expression.

The raw material weighing device of the furnace top charging device of the present invention changes from an empty state inside the bunker to an atmospheric pressure state when the raw material has been charged, and then reaches a pressurized state equal to the furnace internal pressure. A bunker is provided at the top of the furnace, which is charged into the bunker and brought to atmospheric pressure after the inner part is emptied, and the raw materials in the bunker are weighed using a bunker weigher that measures the total weight of the bunker. In the raw material weighing device of the furnace top charging device,
It is equipped with a raw material weigher for pre-weighing the raw materials to be charged into the bunker, and a storage and arithmetic device that inputs the outputs of the raw material weigher and the bunker weigher. The output of the bunker scale at atmospheric pressure is stored as a reference point, and the output of the bunker scale at atmospheric pressure when the raw materials have been input into the bunker is
This is stored as a load corresponding to the load when the inside of the bunker is empty and at atmospheric pressure plus the pre-weighed weight of the raw material charged into the bunker, and the pressurized state when the raw material input into the bunker is completed. The output of the bunker weigher at this time is stored as a load corresponding to the load obtained when the loading of raw materials into the bunker is completed and the bunker is at atmospheric pressure, minus the bunker lifting force due to pressurization inside the bunker, The output of the bunker weigher when the raw material inside the bunker is put into the furnace and the bunker is empty and pressurized is pre-weighed to the load when the bunker is in the pressurized state after the raw material has been put into the furnace. The weight of the raw material charged into the bunker is stored as corresponding to the reduced load, and the relationship between the output of the weigher and the load is determined by statistically processing the stored data. It is characterized by weighing the raw material in the bunker based on the relational expression.

[Function] According to the present invention, the weight of the raw material measured in advance before charging into the bunker and the total weight of the bunker measured by a bunker weighing device such as a load cell are processed, and the output of the bunker weighing device and the negative A relational expression with respect to the load is determined, and the raw materials in the bunker are accurately weighed based on the relational expression.

[Example] Hereinafter, an example of the present invention will be described based on FIG. 1 and FIG. 4. This example shows an example of application to a bellless, two-bun force type furnace top charging and equipment.

First, a furnace top charging device to which the invention of the following is applied will be explained.

In the figure, 1 is the blast furnace main body, and the top of the furnace is equipped with a distribution chute 2, two bunkers 3, and a telescopic pipe 4.
Moreover, a rotating chute 5 is provided inside the blast furnace main body l. The distribution chute 2 is charged with coke in the coke raw material hopper 7 of the raw material equipment and ore in the ore raw material conch p<8 by the raw material charging conveyor 6. The coke and ore are transported to the top of the furnace via the hopper 7.8, and then alternately charged from the distribution chute 2 into the two bunkers 3, and then into the furnace via the rotating chute 5. It is distributed and charged. The bunker 3 has upper and lower seal valves 9 and IO as seal devices, and a pressure equalization pipe for equalizing and discharging the pressure inside the bunker 3! (2) and a gate 12 for adjusting the flow rate of the raw material from inside the bunker 3.

In the raw material weighing device according to the present invention, the bunker 3 is equipped with a sensor 13 for measuring its internal pressure, and a load cell 14 as a bunker weighing device for measuring the dead weight of the bunker 3 is interposed at a location that supports the bunker 3. I'm letting you do it. Further, a load cell 15 as a coke scale for measuring the dead weight of the hopper 7 is provided at a location supporting the raw material hopper 7 for coke, and a load cell 15 as a coke scale for measuring the dead weight of the hopper 7 is provided at a location supporting the raw material hopper 8 for ore. A load cell 16 is provided as a weighing device. Each load cell I4.15.16 is connected to a storage/arithmetic unit 17. As described later, this storage/arithmetic device 17 processes signals from the respective load cells 14, 15, and 16 to weigh the raw material in the bunker 3 with high precision.

Next, the effect will be explained.

The output of the load cell 14 that measures the weight of the bunker 3 exhibits a change over time similar to that shown in FIG. 5 described above. Further, the load cells 15 and 16 accurately weigh the raw materials to be introduced into the bunker 3 in advance. The arithmetic processing unit 17 processes the data from the load cells 14, 15, i6, and first calculates the relationship between the output of the load cell 14 and the load at points A, B, 0, and D in FIG. Find and memorize as follows.

Point A is determined from the output of the load cell 14 immediately before the raw material is introduced into the bunker 3 by the conveyor 6, and this point is stored as a zero load reference point.

Point B is the point at which the raw material hopper 7- is lower than the reference point A, just before the loading of raw materials into the bunker 3 is completed and the pressure is equalized.
It is determined from the output of the load cell 14 at this time, assuming that the load has increased by the amount of input material measured by the load cell I5.16 of 1'8.

The 0 point is calculated by calculating the lifting force equivalent to the bunker internal pressure from the output of the sensor 13 immediately before the pressure equalization in the bunker 3 is completed and the charging of raw materials into the furnace begins, and the load at point B is increased by that amount. It is determined from the output of the load cell 14 at this time, assuming that a load subtracted from the value is applied.

Point D is calculated from the load value at point B just before the charging of raw materials from the inside of the bunker 3 into the furnace is completed and the pressure inside the bunker 3 is evacuated. It is determined from the output of the load cell 14 at this time, assuming that a load is applied by subtracting the lifting force of . At that time, the weight of the raw material charged into the bunker 3 is the weight of the loaded raw material measured by the load cell 15.16 of the raw material hopper 7.8, as in the case of determining point B, and on the other hand, the weight of the raw material input into the bunker 3 is The force is determined from the output of the sensor 13 in the same way as when determining the zero point.

In this way, the load-output data of the load cell 14 at points A, B, 0, and D in FIG. 2 is obtained.

Then, the data regarding points A, B, 0, and D are subjected to statistical processing using least square approximation several times in the past, and the low and decel characteristics are measured when the load increases (from point A to B). point)
and when the load decreases (point C to point D), and calculate the standard approximate curve (see Fig. 3).

In Figure 3, ゛, the mark X is the data for determining Ba point equivalent to point B for coke, the Δ mark is the data for determining the Bb point equivalent to point B for ore, and the mark is equivalent to 0 point for coke. The data for calculating the Ca point of , and the data for calculating the cb point equivalent to 0 point for ore are shown for the seal.For points A and D, regardless of whether the raw material is coke or ore. Desired.

The data regarding point A is indicated by an O mark, and the data regarding point B is indicated by a mark.

Memory calculation device! 7 converts the output of the load cell 14 into a load using the standard approximate curve obtained in this manner. Therefore, among the errors of the load cell 14, errors related to nonlinearity and hysteresis of the load cell characteristics (see FIG. 7), fluctuations in the origin A due to temperature changes, and changes in output are eliminated.

Furthermore, in this example, in order to eliminate the repetition error of the load cell 14 (see FIG. 8), the storage/arithmetic device! 7 has the following functions. That is, after finding the standard approximate curve up to the previous charging (the curve represented by the solid line in Figure 4), while charging the raw material into the bunker 3, find the A point, B point, and 0 point for this time. A on the WA approximation curve at that time. point,
80 points, C.

Slide the standard approximate curve by the deviations dA, dB, and dC from the point. Then, using this sliding standard approximate curve (the curve represented by the two-dot chain line in FIG. 4), the weighing at the time of charging the raw material from point 0 to point D is performed. Therefore, repetition errors of the load cell are eliminated. in general,
This repetition error of the load cell cannot be predicted in advance and cannot be ignored because it occurs to approximately the same extent as the error due to nonlinearity of the load cell characteristics.

[Effects of the Invention] As explained above, according to the present invention, the raw material ff1fi measured in advance before being introduced into the bunker and the bunker weighing device such as a load cell are The total weight of the bunker (measured by the 5 bunkers) is calculated, the relational expression between the output of the bunker weigher and the load is determined, and the raw materials in the bunker are weighed based on that relational expression. be effective.

(1) Non-linearity of characteristics of bunker scales such as load cells,
The influence of error factors such as hysteresis can be significantly improved, and self-correction can be performed through statistical processing based on past data.

(2) It is also possible to cope with long-term fluctuations in the load-output characteristics of the load cell due to changes in temperature and aging.

(3) Measurement accuracy is greatly improved, and the measurement results can be used as feedback signals for controlling the flow rate of raw materials.

(4) Since the timing at which the outflow of raw materials from the bunker to the furnace is completed can be accurately determined, subsequent operations can be started immediately, which is advantageous in terms of time cycle.

[Brief explanation of the drawing]

Figures 1 to 4 are diagrams for explaining one embodiment of the present invention, with Figure 1 being a schematic diagram of the overall configuration of the device, and Figures 2 to 4 explaining the functions of the storage/arithmetic device. Figure 5 is a diagram showing the change over time in the output of the bunker weighing load cell as the furnace top charging device operates, Figure 6 is an explanatory diagram of measurement errors in the conventional raw material weighing method, Figure 7 and 8th
The figure is an explanatory diagram of measurement errors due to the original characteristics of the load cell for bunker weighing. 1...furnace body, 3...banker, 7
・・・・・・Raw material hopper for coke, 8・・・・・・
・Raw material hopper for ore, 9, IO... Seal valve,
11... Pressure equalization pipe, 13... Pressure sensor, ! 4... Bunker scale (load cell), 15... Coke scale (load cell), 16... Ore scale (load cell), 17...・Memory calculation device. Applicant Ishikawajima Harima Heavy Industries Co., Ltd. Figure 5 Figure 6 Procedural amendment (voluntary) ma KO1'V8s 1985 Patent Application No. 151830 2, Name of invention Material weighing method and device for furnace top charging device 3, Amendment person who does

Claims (2)

[Claims] (1) The inside of the bunker goes from an empty state to an atmospheric pressure state when raw materials have been charged, and after reaching a pressurized state equal to the furnace internal pressure, the raw materials inside are charged into the furnace, and then the inside becomes empty. A bunker is installed at the top of the furnace, which is then brought to atmospheric pressure.
In a raw material weighing method for a furnace top charging device in which the raw material in the bunker is weighed using a bunker weigher that measures the total weight of the bunker, the output of the bunker weigher when the inside of the bunker is empty and at atmospheric pressure. is stored as a reference point, and the output of the bunker weigher when the loading of raw materials into the bunker is completed at atmospheric pressure is used as the load when the bunker is empty and at atmospheric pressure. The output of the bunker weigher in the pressurized state when the raw material input into the bunker is completed is stored as the load corresponding to the weight of the input raw material, and the output of the bunker weigher when the raw material input into the bunker is completed is the atmospheric pressure when the raw material input into the bunker is completed. It is stored as a load corresponding to the load obtained by subtracting the bunker lifting force due to pressurization inside the bunker from the load when the bunker is in the state, and the material inside the bunker is put into the furnace and the inside of the bunker becomes empty and pressurized. The output of the bunker weigher at that time corresponds to the load obtained by subtracting the pre-weighed weight of the raw material charged into the bunker from the load when it is in a pressurized state when the raw material input into the bunker is completed. A top equipment for a furnace characterized by storing data, determining a relational expression between the output of a weigher and a load by statistically processing the stored data, and weighing raw materials in a bunker based on the relational expression. Method for weighing raw materials for input equipment. (2) The inside of the bunker goes from an empty state to an atmospheric pressure state when raw materials have been charged, and after reaching a pressurized state equal to the furnace internal pressure, the raw materials inside are charged into the furnace, and the inside becomes empty. A bunker is installed at the top of the furnace, which is then brought to atmospheric pressure.
Then, in the raw material weighing device of the furnace top charging device that weighs the raw material in the bunker using a bunker weighing device that measures the total weight of the bunker, a raw material weighing device that pre-weighs the raw material to be charged into the bunker is used. The storage and calculation device inputs the outputs of the raw material weigher and the bunker weigher, and the storage and calculation device stores the output of the bunker weigher when the inside of the bunker is empty and at atmospheric pressure as a reference point. Then, the output of the bunker weigher when the loading of raw materials into the bunker is completed at atmospheric pressure is calculated as the load when the bunker is empty and at atmospheric pressure, and the weight of the raw material charged into the bunker weighed in advance The output of the bunker weigher in the pressurized state when the raw materials have been input into the bunker is stored as the load corresponding to the load when the raw materials have been input into the bunker at atmospheric pressure. It is stored as a load corresponding to the bunker lifting force due to pressurization inside the bunker, and the bunker weight is calculated when the raw material inside the bunker is put into the furnace and the bunker becomes empty and pressurized. The output of the container is stored as a load corresponding to the load when the material is in a pressurized state after the material input into the bunker is completed, minus the weight of the material charged in advance into the bunker, and these are stored. A furnace top charging device characterized in that it determines a relational expression between the output of a weigher and a load by statistically processing the data stored in the device, and weighs the raw material in the bunker based on the relational expression. raw material weighing device.