JPH1144424A - Method and device for detecting combustion flame in the vicinity of light-emitting body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily judge the burner combustion flame-failure by installing a light intensity reducing filter to reduce the intensity of the light to transmit between a photo sensor part and the combustion flame to discriminate the combustion flame from the light other than the combustion flame, and stopping the supply of the fuel and the combustion support agent during the burner combustion flame-failure. SOLUTION: A fuel burner 1 comprises a fuel gas conduit 2 to feed the fuel gas, and a combustion support gas conduit 3 to feed the combustion support gas. The flame 4 burned by these gases heats a refractory 10 of a degassing tank The intensity of the light at a center part of the combustion flame 4 is detected as the combustion light 6 by a photo sensor 8. The current is excited depending on the intensity of the detected light, and the ON/OFF control is achieved by a combustion control device using the obtained current value through a relay 9. A light reducing or polarizing filter 7 is installed between the combustion flame 4 and the photo sensor 8 to detect only the light of the true combustion flame 4 by removing the light generated from the molten steel. When the light generated from the molten steel is weak in intensity, the light reducing filter is used, while the polarizing filter is used when the light is strong in intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a plurality of light sources and detecting one of the light sources.
The present invention relates to a method for detecting a combustion flame of a burner from another mixed light source using an optical sensor.

[0002]

2. Description of the Related Art Conventionally, a general burner used in a combustion furnace or the like is provided with an optical sensor such as a thermocouple or a phototube outside the burner, and a combustion state by a burner in the furnace.
The temperature, the ignition and the misfire state are detected, and the fuel supply amount is controlled together. The most commonly practiced method is to attach a fixed flame eye to the burner to monitor burner misfire, and if a burner misfires, the flame eye will detect and supply fuel. Methods are in place to stop and prevent explosions and erroneous operations. However, this method is effective when there is a single light source, but it is effective when there are multiple light sources and one of them is detected, especially in a steelmaking process that processes molten steel. When the inside of the degassing tank is heated using a flame burner in the degassing equipment or when the object to be heated is heated using a flame burner in a high-temperature heat treatment furnace, another luminous body is placed near the burner flame. , There is a frequent problem that even the other luminous bodies are erroneously detected and cannot be detected even if the combustion flame is misfired.

[0003] In particular, when the inside of a degassing tank is heated by a flame burner in the above-mentioned vacuum degassing equipment, if a misfire occurs, the processing tank cannot be sufficiently heated, and it is difficult to control the temperature appropriately. Furthermore, if the above-mentioned misfire cannot be detected and the supply of fuel is continued as it is, an explosion occurs in the degassing tank, which may cause serious damage. On the other hand, the degassing process using vacuum degassing equipment and the heat treatment process using a heat treatment furnace are directly connected to other processes in the production line, so if the process is stopped due to misfiring, etc., the other production lines must be stopped. This will cause serious damage to productivity. As described above, it is desired that the above-described process be extremely safe in view of both productivity and loss of productivity due to explosion and erroneous operation in addition to the usual processing technology.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a case where a plurality of light sources exist and one of the light sources is detected.
In particular, when heating the inside of a degassing tank using a flame burner in a vacuum degassing equipment in the steelmaking process to process molten steel, or when heating an object to be heated using a flame burner in a high temperature heat treatment furnace, the combustion of the burner Even if there is another illuminant near the flame, the luminescence generated by the other illuminant is reduced or polarized or eliminated to prevent erroneous operation based on erroneous detection and explosion, thereby improving safety. Another object of the present invention is to provide a method and an apparatus for detecting a combustion flame without impairing the productivity.

[0005]

That is, the present invention provides an optical sensor unit for detecting a combustion flame using an optical sensor when a plurality of light sources are present and one of the light sources is detected. A dimming filter is installed to diminish the intensity of the light that passes between the flame and the combustion flame, making it possible to distinguish between the combustion flame and light other than the combustion flame, and to stop the supply of fuel and auxiliary material in the event of a misfire. This is a method of detecting a combustion flame in the vicinity of the light emitter. Further, in the present invention, when detecting a combustion flame using an optical sensor, a polarizing filter for reducing the light intensity of a specific wavelength is installed between the optical sensor unit and the combustion flame, and other than the combustion flame and the combustion flame. This is a method for detecting a combustion flame in the vicinity of a luminous body, which makes it possible to identify light and to stop supply of fuel and auxiliary material at the time of misfire.

Further, according to the present invention, in a combustion flame detecting device using an optical sensor, a light-reducing filter for reducing light intensity or a polarizing filter for reducing light intensity is provided between the light sensor portion and the combustion flame. This is a device for detecting a combustion flame near the luminous body.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram schematically showing a method for detecting a combustion flame near a luminous body according to the present invention, and is a degassing tank of a vacuum degassing equipment in a steelmaking process for processing molten steel. 1 shows an example of detecting a combustion flame by a combustion burner that heats molten steel in a furnace. In FIG. 1, a combustion burner 1
Is composed of a fuel gas conduit 2 for supplying a fuel gas such as LPG and an auxiliary gas conduit 3 for supplying an auxiliary gas such as oxygen (O ₂ ). The flame 4 burned by the fuel gas and the auxiliary gas is blown out at the tip of the combustion burner 1 to heat the degassing tank refractory 10. On the other hand, the detection of the combustion flame 4 uses the light at the center of the combustion flame 4 as the combustion light 6 and detects the intensity of the light with an optical sensor 8 (a commercially available optical sensor).

The light detected in this way is excited by a current according to the intensity of the light, and is turned on / off by a combustion control device (not shown) provided separately via a relay 9 at the obtained current value.
OFF control. Therefore, if a misfire occurs, the obtained current value falls below a certain level, and the supply valve is closed based on a command to stop the supply of fuel and auxiliary fuel. In the present invention, the characteristic feature is that a neutral density filter or a polarizing filter 7 is provided between the combustion flame and the optical sensor.
Is to set up. That is, there is light emitted from high-temperature molten steel as light other than the combustion flame detected by the optical sensor, and in the past, the detection of combustion flame by the optical sensor often caused malfunctions due to the light emitted from this molten steel, causing a misfire. However, they continued to operate by detecting the light emitted from the molten steel. The above-mentioned neutral density filter or polarizing filter 7 is provided to detect only the light of the true combustion flame, excluding the light emitted from the molten steel.

Regarding the use of the neutral density filter and the polarizing filter 7, when the light emitted from the molten steel is weak, a neutral density filter is used, and when the light emitted from the molten steel is strong, a polarizing filter is used. To detect. Describing a specific detection method, when light emitted from molten steel is weak, detection is performed by a method using a neutral density filter as shown in FIG. FIG. 2 shows a method of dimming in relation to light intensity and wavelength.
The vertical axis represents the light intensity and the horizontal axis represents the wavelength of light, I ₀ is expressed light intensity of a specific level detecting, I _f1 is the light intensity of the burning flame and I _b1 is the light intensity emitted from the molten steel, respectively . FIG. 2A plots the light intensity and the peak value of the wavelength when the combustion flame is directly detected by the optical sensor without passing through the neutral density filter. The light intensity I _f1 of the combustion flame and the light emitted from the molten steel are plotted. Each of the light intensities I _b1 exceeds the light intensity I ₀ of a specific level to be detected, and the optical sensor detects the two light intensities without distinction. Therefore, as shown in FIG. 2B, when the same operation as the former is performed using a neutral density filter, the light intensity I _b2 emitted from the molten steel falls below the specific level of light intensity I ₀ to be detected. Without detection, it is possible to always detect only the light intensity _{If2 of the} combustion flame. That is, as a setting method of the neutral density filter, first, the detection intensity of the optical sensor is ≧ I _0, and then, under the use condition of I _f1 > I _b1 > I ₀ ,
I _f2> I _0> light intensity of I _{b 2} become as combustion flame by setting the dimming filter I _f2 only detection is achieved. In the case where the light intensity I _f2 of the combustion flame has Shitamawa' the light intensity I ₀ of the specific level to be detected, in order to stop the fuel supply acts relay switch which is directly connected to the light sensor because that misfire has occurred fuel The operation is temporarily stopped by turning off the supply valve.

When the light emitted from the molten steel is strong, detection is performed by a method using a polarizing filter as shown in FIG. FIG. 3 also shows a method of polarization in the relationship between light intensity and wavelength, as in FIG. 2, in which the vertical axis represents light intensity, the horizontal axis represents light wavelength, and I ₀ represents a specific level to be detected. The light intensity, I _f1 and I _f2 are the light intensity of the combustion flame and I _f
b1 and _Ib2 represent the light intensity emitted from the molten steel, respectively. The left curve in FIG. 3 represents the peak value (λ _b ) of the wavelength of the light intensity emitted from the molten steel, and the right curve represents the peak value (λ _f ) of the light intensity of the combustion flame. When the light intensity I _b1 emitted from the molten steel is high and exceeds the light intensity I ₀ of the specific level to be detected, the optical sensor captures even the light intensity I _b1 emitted from the molten steel and actually performs the combustion flame. Only the light intensity cannot be measured. Therefore, the use of polarizing filters, the light intensity emitted from the molten steel is lower than the light intensity I ₀ of the specific level to be detected can be reduced to a level of I _b2. On the other hand, the light intensity I _f1 of the combustion flame is also slightly reduced due to the difference in wavelength from the light intensity emitted from the molten steel and reaches the level of If 2, but the light intensity I _f of the specific level still desired to be detected to have Uwamawa' _0, only the light intensity I _f2 of the combustion flame will be detected on the light sensor. That is, as a setting method of the polarizing filter, first, the detection intensity of the optical sensor is ≧ I _0, and then, I _f1 > I ₀ , I _b1 > I ₀ ,
Under the use condition of λ _f ≠ λ _b , I _f2 / I _f1 <I _b2 /
By setting the polarization filter so that I _b1 and I _f2 > I ₀ > I _b2 , detection of only the light intensity I _f2 of the combustion flame is achieved.

In selecting a filter, the light intensity emitted from the molten steel and the light intensity of the combustion flame are measured in advance, and it is better to use either a neutral density filter or a polarizing filter, and based on the measurement result, Can be determined. Furthermore, as another aspect of the present invention, a resistor is built in the optical sensor instead of the above-described neutral density filter or polarizing filter, and the resistance value (current value) flowing through the resistor depending on the magnitude of the obtained light intensity. , It is also possible to detect the light intensity of the combustion flame.

[0012]

As described above, the present invention reduces the light intensity emitted from molten steel even during vacuum evacuation processing in which molten steel is present in a degassing tank of a vacuum degassing equipment in a steelmaking process for processing molten steel. It is possible to always detect the light intensity of the true combustion flame without erroneous detection, and it is possible to easily determine the misfire of the combustion flame and automatically stop the fuel gas and auxiliary combustion gas using it. is there.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a configuration of a light intensity detecting device for a combustion flame in a degassing tank of a vacuum degassing equipment for molten steel.

FIGS. 2A and 2B are diagrams showing a method for detecting the light intensity of a combustion flame when the light intensity emitted from molten steel is weak. FIG. 2A shows actual measured values, and FIG. 2B shows a light reducing filter according to the present invention. It is a figure which shows the result used.

FIG. 3 is a diagram illustrating a method of detecting the light intensity of a combustion flame when the light intensity emitted from molten steel is high, and is a diagram illustrating a result of using a polarizing filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Burner 2 ... Fuel gas supply pipe 3 ... Combustion gas supply pipe 4 ... Combustion flame 5 ... Luminescent body (molten steel) 6 ... Combustion light 7 ... Dimming filter or polarizing filter 8 ... Optical sensor 9 ... Relay 10 ... Degassing tank Refractory

 ──────────────────────────────────────────────────の Continued on front page (72) Inventor Tomomi Yamaguchi 1 Kimitsu, Kimitsu City, Chiba Prefecture Inside Nippon Steel Corporation (72) Inventor Shigeru Ninuma 1 Kimitsu, Kimitsu City, Chiba Prefecture Nippon Steel Corporation (72) Inventor Masahiro Uchida 59 at 46, Nakahara, Oaza, Tobata-ku, Kitakyushu, Fukuoka Prefecture Inside of Nippon Steel Plant Design Co., Ltd. Nippon Steel Plant Design Co., Ltd. (72) Inventor Kiyoharu Ito 2-6-3 Otemachi, Chiyoda-ku, Tokyo Nippon Steel Corporation (72) Inventor Tsutoshi Maeda 2-4 Kyomachibori, Nishi-ku, Osaka-shi, Osaka No. 7 Inside Chugai Furnace Industry Co., Ltd.

Claims (3)

[Claims] In a method for detecting a combustion flame using an optical sensor, a dimming filter for dimming light intensity is provided between the optical sensor unit and the combustion flame to identify the combustion flame and light other than the combustion flame. A method for detecting a combustion flame in the vicinity of a luminous body, wherein the supply of fuel and auxiliary material is stopped when a misfire occurs. 2. A method for detecting a combustion flame using an optical sensor, wherein a polarizing filter for reducing light intensity is provided between the optical sensor unit and the combustion flame so that the combustion flame and light other than the combustion flame can be distinguished. A method of detecting a combustion flame near a luminous body, wherein the supply of fuel and auxiliary material can be stopped when a misfire occurs. 3. An apparatus for detecting a combustion flame using an optical sensor, wherein a light-reducing filter for reducing light intensity or a polarizing filter for reducing light intensity is provided between the light sensor unit and the combustion flame. A detection device for a combustion flame near the illuminant.