JPS60200919A - Temperature controlling method of continuous annealing furnace - Google Patents

Abstract

PURPOSE:To control reasonably the temp. of a continuous annealing furnace by setting previously the radiation correcting value of a radiation thermometer of an annealing furnace by the steel kind, treating pattern of a steel belt, and correcting the thermometer by the steel kind and the treating pattern of the steel belt at the time. CONSTITUTION:The steel belt 2 is run in the continuous annealing furnace 1, heated and annealed by a radiant tube 3. In this case, the temp. of the belt 2 is measured by the radiation thermometer 4, the measured value is corrected by the signal from an overall radiation ratio corrector 5, then the annealing temp. of the belt 2 is controlled to a prescribed temp. by controlling a fuel control valve 9 to the tube 3 by a furnace inside temp. indicating controller 8 based on the relation among the steel belt temp. from a plate temp. controller 6, the furnace temp. signal from a thermocouple for measuring furnace temp. and the set temp. In this case, the radiation ratio correcting rate of the radiation thermometer is determined based on the measured values of contact thermometer and radiation thermometer of every kind of steel and treating pattern of the steel belt, and said ratio is set to a corrected value setting board 10 respectively and the temp. corrected value is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the temperature of a continuous annealing furnace.

In a continuous annealing furnace, the temperature of the material to be treated is radiated every day If
p tongue 1・i li l-11 letter 1 ul Jah 7 1 ul. Although the age of the moss is controlled using a radiation thermometer, it is difficult to use a radiation thermometer because it is affected by changes in the emissivity of the material to be treated and radiation from the furnace walls. It is necessary to correct the emissivity of

Conventionally, for example, two radiation thermometers are used, each consisting of a first radiation thermometer that measures the temperature of the material to be treated and a second radiation thermometer that corrects backlight noise of the first radiation thermometer. By using a thermometer, 1) the emissivity of the radiation thermometer can be corrected, and in view of the fact that the radiation amount fluctuates greatly due to differences in the composition of the material to be treated, the degree of surface use, and the temperature range. A steel plate containing a thermoelectric lamp with the same emissivity as the material to be treated was placed in the furnace, and the emissivity of the radiation thermometer was corrected by alternately measuring this and the material to be treated.

However, the above method can be used for correction under the same conditions when the steel type and treatment pattern are the same, but if the steel type and treatment pattern change, it cannot be corrected quickly, so good temperature control is not possible. The drawback was that it was not possible. Also, Ichimatsu fl + - 1 can of 7M7
Since the emissivity of the buried material is not taken into account, accurate correction cannot be made unless the emissivity of the material to be treated is clear to some extent.On the other hand, in the latter case, Although the emissivity of the treated material can be corrected because the relative positions of the treated material and the steel plate are different, the backlight noise cannot be corrected. The disadvantage was that the thermometer was not corrected accurately, making it difficult to control the temperature inside the furnace.

The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and the emissivity correction value of the radiation thermometer is set in advance according to the steel type and processing pattern, and a predetermined value is determined by a change signal of the steel type and processing pattern. In addition to selecting a correction value, the material temperature measured by the radiation thermometer is corrected using the selected correction value, and the temperature inside the furnace is controlled using this corrected material temperature. The system is designed to quickly respond to changes in the correction value of the meter. It is also an object of the present invention to provide a temperature control method for a continuous annealing furnace that enables accurate temperature control by determining a correction value by comparing the measured values of a contact thermometer and a radiation thermometer. purpose.

Next, the present invention will be explained according to the drawings which are one embodiment.

In FIG. 1, reference numeral 1 denotes a continuous annealing furnace main body, and a running strip 2 is heated and annealed by a radiant tube 31. In this case, the temperature of the strip 2 is measured by a radiation thermometer 4, and the measured temperature is corrected by the signal from the comprehensive emissivity corrector 5, and then the plate temperature controller 6
The fuel control valve 9 to the radiant tube 3 is adjusted by the furnace temperature controller 8 based on the relationship between the strip temperature, the furnace temperature signal from the furnace temperature measuring thermocouple 7, and the set temperature. temperature to a predetermined value.

FIG. 2 shows a contact thermometer 20, which has a small heat capacity.
．． Protection tube 2 equipped with a 3φ thermocouple 21 and a contact detection rod 22
3 is provided to penetrate the furnace wall 24, and when measuring the temperature of the strip 2, the protective tube 23 is inserted through the strip 2.
The thermocouple 21 is gradually brought closer until it comes into contact with the thermocouple 21.
The measured values detected by the thermometer f'sjl' 25 are sequentially recorded, and the saturation value thereof is read.

Note that 2G is a contact indicator light, and 27 is an insertion depth scale plate.

The above correction value is determined by measuring the temperature of the product material for each steel type and treatment pattern using the contact thermometer 20 and the radiation thermometer 1, and determining the emissivity correction value of the radiation thermometer based on the constant values on both sides. The emissivity correction values are respectively set on the correction value setting board 10.

Therefore, during operation, as described above, the measured value from the radiation thermometer 4 is corrected by the correction value, thereby controlling the furnace temperature.

When changing the steel type and processing pattern,
Processing fee data 11 is used for material tracking C,l),U,1
2, and input the processed pattern signal to the correction value setting board 10.
By inputting , a predetermined correction value is selected, this correction value is input to the overall emissivity corrector 5, and the correction value of the overall emissivity corrector 5 is changed.

As described above, according to the present invention, the emissivity correction value of the radiation thermometer is set in advance according to various steel types and treatment patterns, and the optimum correction value is selected depending on the treatment steel type, etc. This makes it extremely easy to change the correction value when changing the value.

In addition, if the correction value is determined based on the temperature actually measured using a contact thermometer, without being affected by radiation from the furnace wall, etc., as in the example, it is possible to accurately determine the temperature of the material to be treated. The temperature can be detected, heating control can be performed more precisely, and energy can be saved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a temperature control method for a continuous annealing furnace according to the present invention, and FIG. 2 is an explanatory diagram of a contact type thermometer. 1-continuous annealing furnace main body, 2-material to be treated, 3-heating means,
4~Radiation thermometer, 5~Comprehensive emissivity corrector, 6~Plate temperature controller, 8~Furnace temperature controller, 9~Fuel control valve,
20 ~ Contact thermometer.

Claims (2)

[Claims] (1) The emissivity correction value of the radiation thermometer is set in advance according to the steel type and processing pattern, and the predetermined correction value is selected by the change signal of the steel type and processing pattern, and the selected correction value is used to A temperature control method for a continuous annealing furnace, characterized by correcting a material temperature measured with a radiation thermometer and controlling the furnace temperature using the corrected material temperature. (2) The continuous annealing furnace according to Paragraph 1 of the Patent Enclosure, wherein the emissivity correction value is determined by comparing a measurement value of a contact thermometer and a measurement value of a radiation thermometer. temperature control method.