JPH01215457A - Method for measuring molten steel weight in ladle - Google Patents

Abstract

PURPOSE:To take out a molten steel in an optimum amt. by specifically processing the successive detected data fed from the weight sensor attached to the ladle in which a molten metal is flowed from a molten steel furnace by comparing with the respective just before data. CONSTITUTION:When a molten steel 2 is flowed into a ladle 4 with a molten steel furnace 1 being tilted, its weight is added to a sensor 6 and its volume is gradually increased. The sensor 6 outputs the detection data corresponding to the weight at every moment. A data processing device 9 inputs this detection data successively comparing it with the just before data on each data. In case of the difference being within a preset threshold value the data are taken at the value as it is. In case of its exceeding the threshold value, the preprocessing executing the correction of excluding the excessive part from the data is executed and the measure value is output by averaging the data subjected to the preprocessing on each specified time. The excessive variation part by the inertia of the fall of a molten steel can be removed in advance by this method.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides the following features when taking out molten steel from a melting furnace into a ladle:
This invention relates to a method for measuring the weight of molten steel in the process of being taken out into a ladle.

[Conventional technology]

A ladle for receiving molten steel from a melting furnace is suspended by a crane via a weight scale, and the weight of the molten steel entering the ladle is measured by looking at the pointer of the scale.

[Problem to be solved by the invention]

In this conventional method for measuring the weight of molten steel in a ladle, not only the true weight of the molten steel that has entered the ladle but also the inertial force of the molten steel falling into the ladle are applied to the scale. For this reason, if the weighing scale is sensitive, the needle of the weighing scale will repeatedly swing far beyond the true value and then return to a value smaller than the true value, causing the needle to swing far beyond the true value. There are problems that make it difficult to judge. As a result, in order to prevent the occurrence of a situation where the amount of molten steel taken out is insufficient,
A large amount of molten steel must be taken out in excess of the required amount, which is uneconomical as the excess amount remains wasted after the taken out molten steel is used.

Furthermore, if the needle of the weighing scale is made to move slowly, even if the amount of molten steel that has entered the ladle increases one after another, the increase in the indication of the needle will be delayed in comparison. For this reason, in order to prevent the amount taken out from being less than the required amount, the operator must take out the excess amount based on the movement of the needle, which causes the same uneconomical problem as mentioned above. Ta.

The present invention has been made in view of the above points, and an object thereof is to provide a method for measuring the weight of molten steel in a ladle that makes it possible to take out an appropriate amount of molten steel.

[Means to solve problems]

In order to achieve the above object, the present invention takes the measures as described in the claims above, and its effects are as follows.

[Effect]

When taking out molten steel, a measured value of the taken out molten steel is obtained. In this case, even if tS* falls into the ladle with inertia, the excessive change due to inertia is excluded in advance from the data obtained from the weight sensor.

Therefore, a measured value close to the true value can be obtained.

〔Example〕

The drawings showing the embodiments of the present application will be described below.

In FIG. 1, l represents a melting furnace, for example an arc furnace, which is configured to be tiltable. Its total capacity is, for example, of the order of 90. 2 indicates molten steel, 3 a receiving line truck, and 4 a ladle placed on the truck 3.

Next, 5 indicates a measuring device for measuring the weight of the molten steel taken out into the ladle 4. In this device, 6 is a weight sensor provided on the trolley 3, The weight of the molten steel is applied to the sensor. This sensor 6
For example, a load cell is used. Reference numeral 7 indicates a measurement circuit. In the circuit 7, 8 is an A/D converter which converts an analog signal from the sensor 6 into a digital signal of, for example, a BCD code. The converter 8 is configured to repeat sampling of data at predetermined intervals, for example, every 33 milliseconds. 9 is a data processing device that processes the data obtained through the converter 8 to calculate a measured value;
It is designed to output a corresponding signal. lO is an indicator.

Next, 11 is a control means for controlling the tilting operation of the melting furnace I.

Next, the operation of the measuring device 5 will be explained. When the melting furnace 1 is tilted and the molten steel 2 flows into the ladle 4 (the speed is, for example, about 100 IK per second), the weight is added to the sensor 6 and its size gradually increases. The sensor 6 momentarily outputs detection data corresponding to its weight.The detection data is also called a sensor signal, and its form is, for example, a voltage signal in mV units.

The detected data is successively inputted to a data processing device 9 through a converter 8. The data processing device 9 first performs the following preprocessing on each data that is input one after another, that is, it compares each data with the immediately preceding data. If the difference is within a predetermined threshold value, the data is left unchanged. On the other hand, if the threshold value is exceeded, the data is corrected to remove the excess amount.

To explain the above preprocessing in more detail, if data nth and data fi+1th satisfy data fi+l ≧ data n and (data n+l) - (data n) ≦K (K is a threshold value and a constant), then data n+l is the same value.

If data n+1) - (data n)>K,
After correcting data n by adding a predetermined value, data fi
Let +l be (data n)+D.

On the other hand, data n + 1 × data n and (data n) - (data n+1) ≦ In this case, data fi+l is left unchanged.

If data n)-(data n+l)>K, correct by subtracting a predetermined value from data n, then data n+
Let l be (data n)-D.

The above threshold value includes the expected flow rate per unit time (for example, 1000 kg) during normal tapping from the melting furnace.
It is best to set the value in accordance with the maximum value of The value is slightly smaller than the above threshold (
For example, it is determined empirically at around 2/3 of the threshold value (for example, 100 kg/3Q milliseconds).

Next, the data processing device 9 calculates an average value from the appropriate number of preprocessed data to obtain a measured value, and outputs it.
The display 10 displays the measured value.

The calculation of the above average value is repeated at time intervals of about 300 milliseconds to obtain a suitable number of data, for example, about 10 pieces, and the display IO displays the measured value that changes (increases) every moment. .

Next, an example of the above pre-processing will be explained based on the graph of FIG. 2. For example, the values plotted with black circles can be obtained as the above detection data. Further, it is assumed that the above threshold value is set at 120 kg. The magnitude of change in detected data 01 to D4 is within the threshold value compared to the immediately preceding detected data (0 for data D1). Therefore, these data should be left as they are. On the other hand, the detected data D5 increases by a change width greater than the threshold value compared to the detected data D4. Therefore, a correction is made to subtract the amount exceeding the threshold,
05".Similarly,
Data D6 is set to the same value, data lower is set to the value shown by 07゛, and data 08 to 01
0 is the value as is.

Next, FIG. 3 shows the preprocessing in another case.As is clear from FIG. 0, in this example, the mouth 1. D2゜D7～
010 is left unchanged, and D3 to 06 are corrected to 03'' to 06°, respectively.

Next, the operation of taking out the required amount of molten steel 2 from the melting furnace 1 to the ladle 4 will be explained. When the melting furnace 1 is tilted, the molten steel 2 sequentially flows into the ladle 4. During the inflow process, the six operators whose measured values are displayed moment by moment on the display 10 as described above watch the displayed measured values and, if the measured values approach the required amount, Take MII4 while returning the tilt of 1.
When the amount of molten steel in the ladle 4 reaches a value predicted to reach the required amount due to the amount further flowing into the ladle, the tilting of the furnace 1 is returned to its original position and the removal is completed. The extracted molten steel is transported to the next process by a cart 3 as is well known.

In the case of the above extraction, if there is uneven inertia of the molten steel 2 flowing down from the melting furnace 1 into the ladle 4, the detection data from the sensor 6 will fluctuate as shown in FIG. If there are irregularities in bad parts, - sometimes a large amount of molten steel 2 flows down into the ladle 4, or the flow becomes thin, and the resulting fluctuations in inertia can cause large irregularities in the detected data. However, because the large unevenness is removed by the pre-processing described above in the data processing device 9, a stable display with small fluctuations can be obtained on the display 10. Therefore, the operator can receive the display with high reliability. can be taken, and the above-mentioned required amount can be taken out accurately without having to allow for a large amount of excess.

Controlling the tilting of the melting furnace 1 described above may be performed automatically by the tilting control means 11. Even in that case, since stable measured values with small fluctuations can be obtained from the signal processing device 9, the tilting control can be performed automatically. The actuation of the means 11 can be carried out precisely.

Next, FIG. 3 shows an example in which the BCD data converted by the converter 8 is collected by the data processing device 9. The transducer 8 samples the signal from the sensor 6 and the B
In this case, when converting to a CD code, there is an undefined time of about 0.02 milliseconds between data confirmation times during each sampling time. The data processing device 9 collects data such as a, b, and c at a cycle shorter than the data determination time 173. Then, sampling data a and b.

At least two of C collect the same data.

Then, among these data a, b, and c, two data having the same value are registered as true detection data.

This makes it possible to prevent abnormal data from being collected during the irregular time period.

〔Effect of the invention〕

As described above, in the present invention, when taking out molten steel from the melting furnace 1 to the ladle 4, not only can the taken out molten steel be taken out without obtaining the measurement value of the taken out molten steel, but also the amount taken out approaches the required amount. Even in the case where the molten steel falls into the ladle 4 with inertia, the excessive change due to the inertia is excluded in advance from the data obtained from the weight sensor 6.
Measured values close to the true values can be obtained, and the problem of extracting a large amount of excess, which is the case with conventional methods, is eliminated, and an appropriate amount can be extracted.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application. Fig. 1 is a block diagram showing a measuring device and its relationship with a ladle, Figs. 2 and 3 are graphs each showing an example of pre-processing, and Fig. 4 is an A/ A diagram for explaining BCD data from a D converter and data collection by a data processing device. ■... Melting furnace, 2... Molten steel, 4... Ladle, 6...
- Weight sensor, 9... data processing device. Figure 1 and Figure N2

Claims (1)

[Claims] 1. When taking out molten steel from a melting furnace into a ladle, a weight sensor that detects the weight of the ladle and outputs detection data is attached in advance to the ladle, and A data processing device is connected to the weight sensor in advance, and during the process in which molten steel flows from the melting furnace into the ladle, detection data from the weight sensor is successively input to the data processing device, and the data processing device compares each detected data with the previous detected data, and if the change is within a predetermined threshold, the detected data is left as is, while if it exceeds the threshold, A method for measuring the weight of molten steel in a ladle, in which preprocessing is performed to correct the excess amount, and the preprocessed detection data is averaged at predetermined time intervals to output the measured value. 2. When taking out molten steel from the melting furnace into a ladle, a weight sensor that detects the weight of the ladle and outputs detection data is attached in advance to the ladle, and the weight sensor is equipped with a A data processing device is connected in advance via a /D converter, and in the process of molten steel flowing from the melting furnace into the ladle, the output from the weight sensor is A/D converted by the A/D converter. , in the above data processing device, the A/D
The converted data is collected one after another at a cycle of 1/3 or less of the sampling time of A/D conversion, and during each sampling time, data with two equal values obtained there is regarded as true detection data, For each true detection data, compare it with each previous detection data,
If the change is within a predetermined threshold, the detected data is left as is, but if it exceeds the threshold, preprocessing is performed to remove the excess. A ladle molten steel weight measurement method that outputs a measured value by averaging the detected data at predetermined intervals.