JP5177703B2 - Foreign matter concentration measurement device in continuous annealing furnace - Google Patents

Description

  The present invention relates to a foreign matter concentration measuring apparatus in a continuous annealing furnace.

  In a continuous annealing furnace for steel strip, foreign matter in the furnace may be caught between the roll and the steel sheet to become a pushing rod, resulting in product defects on the steel strip surface. In particular, in a continuous annealing furnace equipped with a so-called jet cooler type cooling device that cools a steel strip by injecting a cooling gas directly onto the steel strip, foreign matter accumulated in the structure in the furnace is rolled up by the cooling gas, There was a tendency to trigger. In particular, foreign matters having a particle size of 50 μm or more cause the push.

  In response to the above-mentioned product defect problem in a jet cooler, the applicant of the present application removes fine powder such as dust and rust mixed in the cooling gas by a configuration in which a mesh fence is provided between the steel strip and the nozzle header of the jet cooler. In addition, a technique is disclosed in which fine particles such as dust and rust adhered to the mesh fence are washed away by a configuration in which the mesh fence is provided with a water spray nozzle for spraying cooling water on the mesh fence (Patent Document 1).

  In continuous annealing furnaces that produce particularly beautiful steel sheets, such as automotive outer panels, to effectively prevent the occurrence of pushers by identifying the causes of these pushers and examining solutions Therefore, there is a demand for a technique for continuously measuring the concentration of foreign matters (particle diameter and number) in the furnace with high accuracy.

  Conventionally, as a method for measuring the concentration of foreign matter in the furnace, a method is generally known in which the gas in the furnace is sucked and filtered through a cylindrical filter paper or a circular filter paper to collect foreign matter, and observed and quantified with a microscope or the like. Yes. However, this method has a problem that continuous data cannot be obtained, and it is difficult to grasp the details in the furnace in detail, and that a lot of labor and time are required.

In addition, in the particle counter that has been commercially available as a device for continuously measuring the dust concentration, the upper limit of the measurement gas temperature is about 40 ° C. When a sample exceeding the upper limit temperature is flowed, the sensor is damaged by the high-temperature gas. Is done. Since the atmospheric gas temperature in the continuous annealing furnace is about 200 to 300 ° C., there is a problem that it is impossible to measure the concentration of foreign matter using a commercially available particle counter. Although a method of cooling high-temperature gas with a heat exchanger is also conceivable, it is necessary to reduce the gas flow rate in order to ensure contact time with the heat transfer surface. It is difficult to deposit and introduce it to the measuring unit. Furthermore, in the case of cooling with a heat exchanger without reducing the flow velocity, it is necessary to make the heat transfer surface considerably long and the heat exchanger becomes enormous in scale, which is difficult in practice.

Japanese Patent Laid-Open No. 7-3337

  The object of the present invention is to solve the above problems, and in a continuous annealing furnace adopting a jet cooler as a steel strip cooling device, the foreign matter concentration in the high-temperature continuous annealing furnace atmosphere gas, using a conventional commercially available particle counter, An object of the present invention is to provide a foreign matter concentration measuring device in a continuous annealing furnace capable of continuously measuring with high accuracy.

  The foreign matter concentration measuring device in the continuous annealing furnace of the present invention made to solve the above problems is a high-temperature gas inlet for introducing a part of the atmospheric gas in the continuous annealing furnace to the upper part, and a clean gas after the foreign matter removing treatment A cyclone having a clean gas discharge port for discharging foreign matter at the bottom, a foreign matter discharge port connected to the foreign matter discharge port, and a gas flowing through the foreign matter discharge tube. It consists of a particle counter that irradiates a laser from an oscillator, detects scattered light reflected from the foreign matter contained in the gas, and counts the number of foreign matters, and cools the foreign matter discharge pipe in front of the particle counter. A cooling gas supply means for blowing gas is provided.

  The invention according to claim 2 is the foreign matter concentration measuring apparatus in the continuous annealing furnace according to claim 1, wherein the cooling gas supply means is a temperature measuring means for measuring the gas temperature in the foreign matter discharge pipe at the front stage of the particle counter, Cooling gas supply amount determining means for determining the cooling gas supply amount based on the temperature measurement result of the temperature measuring means is provided.

  The invention according to claim 3 is a method for measuring the concentration of foreign matter in the continuous annealing furnace using the foreign matter concentration measuring device in the continuous annealing furnace according to claim 2, wherein the foreign matter concentration in the foreign matter discharge pipe is in front of the particle counter. The supply amount of the cooling gas is determined so that the gas temperature is equal to or lower than the use upper limit temperature of the particle counter.

  According to the foreign matter concentration measuring apparatus in the continuous annealing furnace according to the present invention, the high temperature gas inlet for introducing a part of the atmospheric gas in the continuous annealing furnace to the upper part and the clean gas for discharging the clean gas after the foreign matter removal treatment The sensor is damaged by high-temperature gas, etc., by having a cooling gas blown into a gas that has a discharge port, each having a foreign matter discharge port at the lower part, and a process that uses a cyclone that has a foreign matter discharge port to concentrate the concentration of the foreign matter. Thus, the foreign matter concentration can be continuously measured with a commercially available particle counter. By measuring the concentration with a particle counter using a gas with a concentrated foreign matter concentration as a sample, the foreign matter concentration in the furnace can be grasped continuously and with high accuracy.

It is a whole explanatory view of the foreign substance concentration measuring device in the continuous annealing furnace concerning the present invention. It is a figure which shows the effect of this invention by an Example.

  Preferred embodiments of the present invention are shown below.

  As shown in FIG. 1, the apparatus for measuring the concentration of foreign matter in a continuous annealing furnace according to the present invention includes a cyclone 1 and a foreign matter discharge port 4 provided at the lower part of the cyclone 1 for discharging foreign matter separated by the cyclone 1. A foreign matter discharge pipe 6 connected in the vertical direction directly below the cooling gas supply means 7, a cooling gas supply means 7 for blowing cooling gas into the foreign substance discharge pipe 6, and a particle counter 9 for measuring the number of particles in the cooled gas. Yes. The particle counter 9 has a conventionally known configuration, and when the gas is irradiated with a laser from a laser oscillator via a galvano mirror, the particle counter 9 is reflected from foreign matter (fine particles) contained in the gas. Light is detected by a photomultiplier through a lens and a slit, processed by a signal processing circuit, counted, and displayed on a counting display or the like.

  The overall shape of the cyclone 1 can be determined by a conventionally known general formula using parameters such as the diameter and density of a foreign substance to be removed and the physical properties and air volume of a fluid.

  The cyclone 1 has a high-temperature gas introduction port 2 for introducing a part of the atmospheric gas in the continuous annealing furnace at the upper portion and a clean gas discharge port 3 for discharging the clean gas after the foreign matter removal treatment, and has a foreign matter at the lower portion. It has a foreign matter discharge port 4 for discharging. Moreover, it is preferable to install a vibrator 5 at the lower part of the cyclone to prevent foreign matter from accumulating on the inclined part at the lower part of the cyclone.

  The atmosphere gas in the continuous annealing furnace is sucked into the cyclone 1 by the atmosphere gas suction means 10 in the continuous annealing furnace installed at the subsequent stage of the clean gas discharge port 3. As the atmospheric gas suction means 10 in the continuous annealing furnace, any suction means such as a heat-resistant suction pump or ejector can be adopted, but it is particularly preferable to adopt an ejector from the viewpoint of cost.

  The atmospheric gas in the continuous annealing furnace is a high temperature gas of about 200 to 300 ° C. The temperature of the gas concentrated in the cyclone 1 and discharged to the foreign matter discharge pipe 6 is about 150 to 250 ° C.

  The foreign matter discharge pipe 6 is provided with a cooling gas supply means 7 for cooling the cooling gas inside the foreign matter discharge pipe 6 to below the upper limit temperature (about 40 ° C.) of a commercially available particle counter. The upper limit temperature of the particle counter is defined by the heat resistant temperature of the particle counter sensor.

  The cooling gas supply means 7 is a temperature measurement means 8 that measures the gas temperature in the foreign matter discharge pipe 6 in the previous stage of the particle counter 9, and a cooling that determines a cooling gas supply amount based on the temperature measurement result of the temperature measurement means 8. Gas supply amount determination means 11 is provided.

  In the cooling gas supply amount determination means 11, the gas temperature in the foreign matter discharge pipe 6 at the front stage of the particle counter 9 is based on the temperature measurement result of the temperature measurement means 8 and the upper limit temperature (about 40 ° C.) of the particle counter 9 is used. The supply amount of the cooling gas is determined and the opening / closing control of the cooling gas supply amount adjustment valve 12 is performed so as to be as follows.

  In the present invention having the above-described configuration, the high-temperature concentrated foreign substance mixed gas separated by the cyclone 1 is introduced into the particle counter 9 after being mixed with the cooling gas. It is possible to grasp the concentration of foreign matter in the inside with high accuracy.

  The result of having examined the effect of this invention using the foreign material density | concentration measuring apparatus in the continuous annealing furnace shown in FIG. 1 is shown below.

  Furnace atmosphere gas (200 to 300 ° C.) was introduced into the cyclone 1 (φ100 mm * L300 mm) from the continuous annealing furnace.

  The introduced gas is repeatedly exhausted in the cyclone 1 and then exhausted from the clean gas discharge port 3. When the gas swirls, foreign matter having a large particle diameter (10 μm or more) settles in the lower part of the cyclone 1. Here, since the foreign matter is vibrated by the vibrator 5 when it settles, it settles without adhering to the inner wall of the cyclone 1.

  The settled foreign matter is discharged into the foreign matter discharge pipe 6 and mixed with the cooling gas so as to be lower than the upper limit temperature (about 40 ° C.) of the particle counter, and then introduced into the particle counter 9 to determine the diameter and number of the foreign matter. Measured.

FIG. 2 shows the result of measuring the concentration of foreign matter according to the above example. As shown in FIG. 2, according to the present invention, it is possible to continuously measure the concentration of foreign matter in a high-temperature gas,
It is possible to quickly investigate the causal relationship with the occurrence of soot in the furnace.

DESCRIPTION OF SYMBOLS 1 Cyclone 2 High temperature gas introduction port 3 Clean gas discharge port 4 Foreign material discharge port 5 Vibrator 6 Foreign material discharge pipe 7 Cooling gas supply means 8 Temperature measurement means 9 Particle counter 10 Continuous annealing furnace atmosphere gas suction means 11 Cooling gas supply amount determination means 12 Cooling gas supply control valve

Claims (3)

  The upper part has a high-temperature gas inlet that introduces part of the atmospheric gas in the continuous annealing furnace and a clean gas outlet that discharges the clean gas after the foreign substance removal treatment, and a foreign substance outlet that discharges foreign substances at the lower part. A cyclone having a foreign substance discharge pipe connected to the foreign substance discharge port, and a gas flowing through the foreign substance discharge pipe is irradiated with a laser from a laser oscillator to reflect scattered light reflected from the foreign substance contained in the gas. Contaminant concentration measurement in a continuous annealing furnace characterized by comprising a particle counter that detects and counts the number of foreign substances, and provided with a cooling gas supply means for blowing cooling gas into the foreign substance discharge pipe in front of the particle counter apparatus.   The cooling gas supply means includes a temperature measurement means for measuring the gas temperature in the foreign matter discharge pipe at the front stage of the particle counter, and a cooling gas supply amount determination means for determining the cooling gas supply amount based on the temperature measurement result of the temperature measurement means. The apparatus for measuring a foreign matter concentration in a continuous annealing furnace according to claim 1, comprising: A method for measuring the concentration of foreign matter in a continuous annealing furnace using the foreign matter concentration measuring device in a continuous annealing furnace according to claim 2, wherein the gas temperature in the foreign matter discharge pipe at the front stage of the particle counter is the use of the particle counter. A foreign matter concentration measurement method in a continuous annealing furnace, wherein a supply amount of a cooling gas is determined so as to be equal to or lower than an upper limit temperature.

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