KR200216600Y1 - Dust level measuring device using resistance detection method - Google Patents

Abstract

The present invention relates to a level measuring apparatus for measuring a dust level in a blast furnace, and more particularly, it is possible to measure a dust level value in a condition where the internal atmosphere changes by reading the dust resistance value inside the dust collector using a measuring plate and a reference plate And a level measuring apparatus using the resistance detection method.

The present invention is characterized in that two holes 7 are drilled to form a level detecting device 2 on the outside of the dust collector 1 to form a flange 6 and a flange hole 8 to form two level measuring devices 2 Is mounted to the dust collector 1 and a reference plate 4 and a measurement plate 3 are installed in the dust collector 1 and the level measurement plate 3 and the reference plate 4 are connected to the ground 19, and a current value of the measurement resistance means is compared with a current value of the reference resistance means, and the current value of the reference resistance means is compared with the dust resistance value of the dust collector It is to measure the dust level.

Description

Dust level measuring device using resistance detection method

The present invention relates to a level measuring apparatus for measuring a dust level in a blast furnace, and more particularly, by measuring a dust resistance value in a dust collector using a measuring plate and a reference plate, an accurate dust level value can be measured To a dust level measuring apparatus using resistance detection method.

Accurate measurement of the height and volume of dust levels in closed conduits, ie blast furnaces, such as blast furnaces, is critical to the production of smooth products by increasing the efficiency of primary dust collectors and informing them of proper discharge times.

The measurement of the dust level inside the dust collector such as the blast furnace indicates the proper discharge time point of the dust collector to prevent clogging of the dust collector 1 and the secondary dust collector valve due to accumulation of dust in the excessive dust collector, It is essential to carry out in advance to prevent the risk of discharging the toxic gas from the blast furnace to the blast furnace.

The conventional method of measuring the dust level is widely used depending on the structure of the dust collector, internal pressure, temperature, dust component, dust particle size, and the nature of the dust collector structure.

A dust level measuring method of a currently installed dust collecting apparatus is as follows. A thermocouple (refer to reference numeral 5 in FIG. 1) installed at the time of blast furnace installation is installed outside the dust collector There is a method of detecting the dust level by measuring the temperature by inserting it at a predetermined interval on the surface of the dust collector so as to penetrate the inside of the dust collector.

The principle of this dust level detection method is that the temperature of the outer surface of the dust collector, that is, the temperature inside the dust collector is high at 500 ° C or more, the temperature outside the dust collector is low due to heat conduction interruption due to dust, The outer surface of the dust collector is heated by the hot gas at 500 ° C, and the temperature is elevated. At this time, the boundary between the surface where the dust is accumulated and the surface where the dust is not accumulated is detected by the temperature distribution analysis method according to the measured temperature have.

While this method has the merit of being simple to configure, in order to accurately analyze the temperature distribution, that is, to detect the dust level inside the dust collector, many thermocouples should be placed on the surface of the dust collector to measure the data. In order to improve the reliability of the data, Exchange and maintenance are required.

In addition, there is a difficulty that the temperature distribution analysis model must be actively changed according to the temperature condition outside the dust collector, that is, the season (the summer where the external temperature is much increased and the winter temperature falls below zero), and the weather (wind, rain, snow, .

In another method, a load cell is mounted on a support stand or the like supporting the dust collector at the initial stage of construction of the dust collector by a method used in a Japanese blast furnace factory (Japanese Patent Application Laid-Open No. 5-202364), and the weight of dust accumulated in the dust collector is immediately transferred to the load cell It is a method to measure the dust level inside the dust collector by analyzing the correlation between the load value of the load cell and the dust level.

The advantage of this method is that once it is installed, little maintenance is required and accurate data acquisition is possible.

However, the disadvantage is that, in the facilities where the load cell is not installed on the supporting table when the initial dust collector is expanded or shrunk as in the blast furnace of Pohang, the existing supporting columns (columns) are cut out so that the load cell can be installed, There is a difficulty to reinforce it again, and it is an impossible measurement method in facilities such as Pohang.

Another technique is to use an ultrasonic sensor or a radar sensor, which is used in factories such as a cement factory and a flour mill, to install ultrasonic sensors or radar sensors on the dust collector, To measure the dust level. This method is widely used in places such as oil refineries.

The advantage of this method is that it is easy to install and can obtain highly reliable data. On the other hand, there are disadvantages in that there are many constraints on the inside of the dust collector, that is, temperature and pressure, for application to high temperature and high pressure environments such as blast furnace have.

Usually, the temperature inside the blast furnace increases to almost 500 ° C, and the pressure also rises to three times the atmospheric pressure. The operating range of ultrasound or radar sensor developed up to now can be less than 200 ° C or up to twice the atmospheric pressure, and it can not be used in a blast furnace environment.

In addition to the above-mentioned prior arts, various methods such as a capacitance level measurement method, a laser beam measurement method, an X-ray measurement method, and a measurement method using a thermal sensing vision system are known as patents, have.

However, due to the constraints such as temperature, pressure, internal convection in the dust collector, it is difficult to measure the dust level by the conventional detection method for application to a special environment such as a blast furnace.

Accordingly, the inventor of the present invention has conducted studies and experiments to improve the disadvantages of the above-described conventional methods, and has come to propose the present invention based on the results.

The purpose of this design is to measure the level of dust in the blast furnace. By measuring the dust resistance inside the dust collector using the measuring plate and reference plate, accurate dust level can be measured And to provide a dust level measuring apparatus using the resistance detection method.

FIG. 1 is a schematic view of a dust level measuring apparatus according to the present invention; FIG.

FIG. 2 is a schematic view of a flange portion of the inventive dust level measuring device. FIG.

FIG. 3 is a schematic view of the mechanical structure of the inventive dust level measuring device. FIG.

FIG. 4 is an electric circuit block diagram of the inventive dust level measuring apparatus.

5 is an overall structural view of the inventive dust level measuring apparatus.

DESCRIPTION OF THE REFERENCE NUMERALS

1: dust collector 2: flange portion

3: Measuring plate 4: Reference plate

5: Thermocouple 6: Flange

7: Pipe 8: Flange hole

9: Reference resistance 10: Measuring resistance

11: Measuring ammeter 12: Reference ammeter

13: Switch 14: Reference resistance 1

15: reference resistance 2 16: operational amplifier 1

17: operational amplifier 2 18: relay circuit

19: Ground (GND) 20: Level detection controller

21: computer 22: reference voltage source

23: analog / digital conversion circuit 24: memory

25: central processing unit 26: digital / analog conversion circuit

27: Level indicator

In order to achieve the above object, a dust level measuring apparatus using a design resistance detection method has a structure in which two holes 7 are formed in upper and lower sides to form a flange 6 and a flange hole 8, A measurement plate 3 and a reference plate 4 are installed in the dust collector 1 and a voltage source 22 for providing a reference voltage is connected to a switch 13 and a measurement ammeter 11 And connecting the reference plate 4 through the switch 13 'and the reference ammeter 12 so as to connect the measurement plate 3 and the reference plate 4 with each other, The current from the voltage supply source 22 flows through the measurement plate 3 and the reference plate 4 respectively with the measurement resistor 10 and the reference resistor 9 formed as a load between the ground 19 and the measurement resistor 10, (10) which is increased by the dust And the dust level in the dust collector is measured by comparing the measured current with the current flowing through the reference resistor 9. [

Hereinafter, the present invention will be described with reference to the accompanying drawings. 1 is a view for explaining the concept of the present inventive device. In order to provide a flange portion 2 outside the dust collector 1, two holes 7 having a diameter of 76.4 mm are drilled to form a flange 6 and a flange hole 8 and the two flange portions 2 are fastened to the outside of the dust collector 1 by the flange 6 and then the reference plate 4 and the measurement plate 3 are installed therein.

3, the dust level measuring apparatus includes a measuring plate 3, a reference plate 4, a dust measuring resistor 10 and a reference resistor 9 (see FIG. 3) An ammeter 12 for measuring the current flowing through the reference plate 4 and an ammeter 11 for indicating the value of the current flowing through the measuring plate 3, a ground 19 and a voltage supply source 22.

FIG. 4 is a block diagram of an electric circuit connected to the dust level measuring apparatus of FIG. 3; FIG. First, the dust detection mechanism will be described in detail. Since the dust has electric conductivity, when the area where the measurement plate 3 and the dust meet is increased, the resistance value of the measurement resistor 10 is reduced, The current flowing between the surface of the substrate 1 (the hopper body, that is, the ground GND) is also increased.

Conversely, if the area of contact with the dust decreases, the current flowing between the measuring plate 3 and the surface of the dust collector 1 through the dust decreases.

The reference plate 4 is provided with a reference plate 4 having a fixed length L _ref and having the same surface area as the measuring plate 3 per unit length and the current I _ref flowing in the reference plate 4 is measured by an ammeter 12 ).

The current I _meas flowing between the measuring plate 3 and the ground 19 through the current flowing through the measuring plate 3, that is, the dust, is measured through the ammeter 11 in the above manner. The following equation is satisfied between the measured I _ref and I _meas .

[Equation 1]

In Equation (1), DEPTH _dust represents the depth (height) of the dust.

≪ RTI ID = 0.0 >

&Quot; (2) "

From the results shown in Equation 2, even if the electrical conductivity of the dust changes depending on the humidity and the temperature combustion state, the depth of the dust is measured as the ratio of I _ref and I _meas current, so that the influence of the above variables is eliminated . Because I _ref , I _meas, and I _meas are measured simultaneously at every measurement, the measurement conditions of the two currents are the same.

Hereinafter, the measurement method will be described in detail.

Referring to the measurement electric circuit, as shown in FIG. 4 and FIG. 5, the resistance R _dustref of the reference plate 4 is measured first. The measurement method is as follows.

Let V _dac (DAC) be OV. This is because it is safe to turn on / off the relay after setting the output voltage of the DAC to OV because the dust inside the dust collector may be flammable.

The next relay circuit is turned off. In the off state, the reference plate 4 is selected in the dust collector.

Then increase to Vdac = 5V. Then, the both-end voltage V _ref2 of R _ref2 of the reference amplifier plate 4 current amplification circuit 17 is measured. R _{ref2 The} resistance value can be adjusted when it is necessary to adjust the gain according to the measured current value. Usually, 100KΩ is used. The following measurement equation can be obtained by this measurement.

&Quot; (3) "

In Equation (3)

&Quot; (4) "

Can be obtained. In Equation 4, V _ref2 (the voltage across R _ref2 ) is known by measurement, and R _ref2 is a value known as the resistance of the circuit.

The following describes the process of obtaining R _dustmeas .

Let V _dac (DAC) be OV. This is because it is safe to turn on / off the relay after turning the DAC output voltage to OV because the dust inside the dust collector may be flammable. Turn on the next relay circuit. When it is turned on, the measuring plate 3 is selected in the dust collector.

Then increase to V _dac = 5V. Then, the both-end voltage V _ref1 of R _ref1 of the measurement plate current amplification circuit 16 is measured. The R _ref1 resistance can be adjusted when it is necessary to adjust the amplification factor according to the measured current value. Usually, looKΩ is used. The following measurement equation can be obtained by this measurement.

&Quot; (5) "

In Equation (5)

&Quot; (6) "

Can be obtained. In Equation 6, Vrefl (the voltage across R _refts ) is known by measurement, and R _ref1 is a value known as the resistance of the circuit.

Depth of _dust DEPTH _dust is obtained by substituting R _dustref and R _dustmeas obtained in the above into Eq. (2) to obtain DEPTH _dust of _dust .

The controller portion of the inventive dust level measuring apparatus will be described in detail with reference to FIG. The height (depth) DEPTH _dust of the dust detected in the above process is composed of the controller 20, the central processing unit 25, the memory 24, the analog / digital converter 23, and the digital / Can be calculated through a circuit system.

The analog-to-digital converter 23 measures the height of the dust collector by dividing the dust collector height into 1,024 by using 10 bits, and the digital-to-analog converter 26 measures O [V] to 10 [V ].

The central processing unit 25 uses Intel Corporation's 80C196 central processing unit because it has a built-in 10-bit analog-to-digital converter 23 that simplifies the configuration of the controller 20 have.

The level display circuit 27 displays the level value with the 7-segment LED.

In order to increase the efficiency of the level detecting apparatus, a plurality of level detecting apparatuses using such a resistance measuring method are installed, and each apparatus is grouped into an RS-485 communication network so as to be concentratedly managed by the computer 21.

In the present invention as described above, the measurement plate and the reference plate are provided in the dust collector, and the resistance value of the carbon component dust between them is measured to evaluate the environmental factors such as the humidity, temperature, Stable and accurate measurement of the dust level is possible without being influenced.

Claims (1)

Two flanges 6 are formed on upper and lower sides to form flanges 6 and flange holes 8 so that the two flanges 2 are fastened to the dust collector 1, The measurement plate 3 is connected to the voltage source 22 providing the reference voltage through the switch 13 and the measuring ammeter 11 and the switch 13 The measurement resistor 10 is formed between the measurement plate 3 and the reference plate 4 by connecting the reference plate 4 through the reference ammeter 12 and the reference ammeter 12, A current flowing through the measuring resistor 10 which is increased by dust is configured so that the current by the voltage supply source 22 flows through the measuring plate 3 and the reference plate 4 with the reference resistor 9 as a load, Is compared with the current flowing in the reference resistor 9, And measuring the level of the dust level by using the resistance detection method.