JP2009174958A - Temperature-measuring device of steel plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature-measuring device of a steel plate capable of measuring the temperature of the steel plate rapidly and with accuracy, without being affected by variations and changes with the passage of time, in each emissivity of a steel plate to be measured and a reflecting plate. <P>SOLUTION: The temperature-measuring device of a steel plate includes: a channel 8 constituted of the reflecting plate 2, partition walls 4a, 4b, and a backplane 5; an electric heater 20 provided in the channel 8; a cooling gas 50 flowing in the channel 8; a power supply 25 for electric heaters for allowing current to flow to the electric heater 20; a solenoid valve 55 and a regulator 56 for supplying the cooling gas 50; a control means 30 for sending a command to them; and a steel plate temperature arithmetic circuit 60 for calculating an approximate value T<SB>1</SB>', which is regarded as steel plate temperature, based on radiosity temperature Tg, obtained by a radiation thermometer 3 from radiosity reflected between the reflecting plate 2 and the steel plate and reflecting plate temperature T<SB>2</SB>which is measured by a thermocouple 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steel plate temperature measuring apparatus that can be used in, for example, continuous annealing equipment and alloyed hot dip galvanizing equipment and can measure the temperature of the steel sheet in a non-contact manner.

  In continuous annealing equipment for continuously heat-treating steel sheets and galvannealed equipment for galvanizing after hot-dip plating, various types of steel sheets are continuously processed. For this reason, in order to stabilize the mechanical properties (strength, elongation, etc.) and plating properties (degree of alloying, etc.) of steel plates that differ for each product type, the steel plate temperature after the heat treatment process with heating / cooling is set to the target temperature. It is important to control accurately.

  In general, the temperature of a steel sheet continuously conveyed in these facilities is measured using a non-contact radiation thermometer. When using a radiation thermometer, it is necessary to set the emissivity of the steel sheet that is the object to be measured. However, the emissivity of the steel sheet varies depending on various factors such as the steel sheet temperature, the physical properties of the steel sheet itself, such as the steel type and the surface properties, and in practice, the emissivity of the steel sheet is set corresponding to such fluctuations. It is very difficult. As a result, there is a problem that an error is likely to occur in the measurement of the steel plate temperature, and the steel plate temperature cannot be accurately controlled to the target temperature.

  The following is proposed as a steel plate temperature measuring device for eliminating the influence of the emissivity fluctuation of the steel plate as much as possible and measuring the steel plate temperature with high accuracy. "Knowing that multiple reflections between a reflector and a steel plate increase the apparent emissivity" and the radiation of the reflector by controlling the temperature of the reflector by installing heating means on the back of the reflector An apparatus for measuring a temperature of a steel sheet has been proposed that is configured under the “intent to be unaffected by changes in the rate over time” (see, for example, Patent Document 1).

  In addition, as a temperature measuring device for a steel plate intended to prevent breakage of a furnace wall brick, etc. even if the steel plate breaks in the furnace and the comparative plate breaks, Things have been proposed. “A comparison plate installed close to the steel plate that can be cooled by gas, a temperature detector for measuring the surface temperature provided on this comparison plate, radiation from the steel plate, and radiation from the comparison plate There has been proposed a temperature measuring device for a steel plate that includes a radiation thermometer for measurement and is configured to obtain the temperature of the steel plate from the measurement value of the radiation thermometer (see, for example, Patent Document 2).

  However, in the steel plate temperature measuring device described in Patent Document 1, in order to enable temperature measurement with high accuracy in principle, the number of multiple reflections must be infinite (or considered to be infinite). Don't be. Moreover, when comprised in this way, a quaternary type | formula is materialized between the temperature of a steel plate, the multiple reflection temperature measured with the radiation thermometer, and the temperature of a reflecting plate. However, it takes a long time to calculate the temperature of the steel sheet by solving this quaternary equation. Therefore, calculation is performed using a first-order approximation formula. However, if there is a difference between the multiple reflection temperature measured by the radiation thermometer and the temperature of the reflecting plate, a minute term in the linear approximation formula cannot be ignored in obtaining the temperature of the steel plate with high accuracy. However, in this temperature measuring device, since only the heating means is provided on the reflection plate, the multiple reflection temperature measured by the radiation thermometer cannot be quickly matched with the temperature of the reflection plate. Therefore, the temperature of the steel sheet cannot be obtained quickly and accurately. In particular, when the reflector is heated too much by the heating means, since the cooling means is not provided, it takes a very long time to match the target reflector temperature and the multiple reflection temperature measured by the radiation thermometer. There is a problem that it requires.

In addition, the steel plate temperature measuring device described in Patent Document 2 has a cooling means on the comparison plate but no heating means, so that it cannot be quickly controlled to the target reflector temperature, but in the first place. In principle, this apparatus does not take into account the effects of fluctuations in emissivity and changes with time of the steel plate and reflector. Therefore, there is a problem that the temperature of the steel sheet cannot be measured quickly and accurately.
JP-A-5-203497 JP 52-44681 A

  An object of the present invention is to provide a steel plate temperature measuring apparatus capable of measuring a steel plate temperature quickly and accurately without being affected by variations in emissivity and changes with time of the steel plate to be measured and the reflector. .

In order to achieve this object, the invention according to claim 1 of the present invention includes a reflector provided opposite to a steel plate to be measured and provided with a flow path, and a heater provided in the flow path. Or a high temperature medium supply means for flowing a high temperature medium through the flow path, a low temperature medium supply means for flowing a low temperature medium through the flow path, and the heater or the high temperature medium supply means and the low temperature medium supply means. and control means, the temperature of the reflection plate (hereinafter, referred to as "reflective plate temperature".) and a temperature detector for measuring T ₂ directly, the radiant energy emitted from each of said reflecting plate to be measured steel sheet wherein It is installed toward the steel plate to be measured so that the angle is reflected a predetermined number of times between the reflector and the steel plate to be measured, and the energy released from the steel plate to be measured is measured at this angle, and this measurement is performed. Energy and A radiation thermometer for converting to an equivalent temperature _Tr corresponding to the temperature of a black body that radiates equivalent energy and outputting it, and the temperature of the steel plate to be measured (hereinafter referred to as “steel plate temperature”) from the following equation (1). A steel plate temperature calculation circuit for calculating an approximate value T ₁ ′ of
The flow path is provided on a surface of the reflector opposite to the steel plate to be measured (hereinafter referred to as “back surface”), and the reflector temperature T ₂ matches the approximate value T ₁ ′. The temperature measurement of the steel sheet, wherein the heater or the high temperature medium supply means and the low temperature medium supply means are controlled by the control means, and the approximate value T ₁ ′ is regarded as the steel plate temperature. Device.
T ₁ ′ = T _r + K (T _r −T ₂ ) ——Expression (1)
Here, K is a correction coefficient based on estimated values of the emissivities of the reflector and the steel plate to be measured, which are obtained from separate measurements or literature values.

The invention according to claim 2 is the invention according to claim 1, wherein the measured energy is obtained by radiating energy radiated from each of the steel plate to be measured and the reflecting plate, and the steel plate to be measured and the steel plate to be measured. And the equivalent temperature T _r is an emissivity obtained by converting to the temperature of a black body that radiates energy equivalent to the emissivity. a temperature _{T g.}

The invention according to claim 3 is the invention according to claim 1, wherein the measured energy is obtained by radiating energy radiated from each of the steel plate to be measured and the reflecting plate, and the steel plate to be measured and the steel plate to be measured. Radiant energy from the steel sheet to be measured when multiple reflection is performed between the two and the equivalent temperature T _r is obtained by converting to the temperature of a black body that radiates energy equivalent to the radiant energy when the multiple reflection is performed. and a multiple reflection temperature _{T m.}

According to a fourth aspect of the present invention, in the first to third aspects of the invention, the flow path includes the reflection plate, a plurality of partition walls provided so as to contact the back surface of the reflection plate, and the reflection. The back plate provided to face the back surface of the plate, and the back plate side has a configuration having a supply port to which the low-temperature medium or the high-temperature medium is supplied and a discharge port to be discharged. An electric heater, which is disposed over the entire flow path, and the thickness t of the reflector and the interval W between the plurality of partition walls, and the thickness H and the height of the partition walls. The relationship with the length L is configured to satisfy the following expressions (2) and (3).
2 ≦ W / t ≦ 10 ――― Formula (2)
1 ≦ L / H ≦ 20 ――― Formula (3)

  The invention according to claim 5 is the invention according to claim 4, wherein the supply port is provided in the vicinity of the center of the flow path, the discharge ports are provided at both ends of the flow path, and the low-temperature medium is provided. Alternatively, the high-temperature medium is configured to flow from the vicinity of the central portion toward the both end portions.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the low temperature medium is a low temperature gas, and the flow rate of the low temperature gas is supplied from the low temperature medium supply means at a plurality of levels according to a command from the control means. It is configured to be able to.

As described above, the steel plate temperature measuring device according to the present invention is installed on the reflecting plate provided opposite to the steel plate to be measured and provided with the flow path, and the heater or the flow path provided in the flow path. A high temperature medium supply means for flowing a high temperature medium, a low temperature medium supply means for flowing a low temperature medium through the flow path, a control means for controlling the heater or the high temperature medium supply means and the low temperature medium supply means, the temperature of the reflector (hereinafter, referred to as "reflective plate temperature".) the temperature detector for measuring the T ₂ directly, the radiant energy emitted from each of said reflecting plate to be measured steel plate and the reflective plate to be Installed toward the steel plate to be measured so that the angle is reflected a predetermined number of times from the measuring steel plate, and the energy released from the steel plate to be measured is measured at this angle and is equivalent to the measured energy. Energy And a radiation thermometer for converting to an equivalent temperature _Tr corresponding to the temperature of a black body that emits light, and the temperature of the steel plate to be measured (hereinafter referred to as “steel plate temperature”) from the following equation (1). A steel sheet temperature calculation circuit for calculating an approximate value T ₁ ′,
The flow path is provided on a surface of the reflector opposite to the steel plate to be measured (hereinafter referred to as “back surface”), and the reflector temperature T ₂ matches the approximate value T ₁ ′. The control means controls the heater or the high temperature medium supply means and the low temperature medium supply means, and the approximate value T ₁ ′ is regarded as the steel plate temperature. The steel plate temperature can be measured quickly and accurately without being affected by fluctuations in emissivity and changes with time.
T ₁ ′ = T _r + K (T _r −T ₂ ) ——Expression (1)
Here, K is a correction coefficient based on estimated values of the emissivities of the reflector and the steel plate to be measured, which are obtained from separate measurements or literature values.

  Hereinafter, embodiments of the present invention will be described.

A temperature measuring apparatus for a steel sheet according to the present invention is installed opposite to a steel sheet to be measured and has a reflector provided with a flow path and a heater provided in the flow path or a high temperature medium flowing through the flow path. A high-temperature medium supply means, a low-temperature medium supply means for flowing a low-temperature medium through the flow path, a control means for controlling the heater or the high-temperature medium supply means and the low-temperature medium supply means, A temperature detector that directly measures temperature (hereinafter referred to as “reflecting plate temperature”) T ₂ , and radiant energy radiated from each of the steel plate to be measured and the reflecting plate is measured between the reflecting plate and the steel plate to be measured. It is installed toward the steel plate to be measured so that the angle is reflected a predetermined number of times, and the energy released from the steel plate to be measured is measured at this angle, and the energy equivalent to the measured energy is radiated. You A radiation thermometer for converting to an equivalent temperature _Tr corresponding to the temperature of the black body and outputting it, and an approximate value T of the temperature of the steel plate to be measured (hereinafter referred to as “steel plate temperature”) from the following equation (1). A steel sheet temperature calculation circuit for calculating ₁ ',
The flow path is provided on a surface of the reflector opposite to the steel plate to be measured (hereinafter referred to as “back surface”), and the reflector temperature T ₂ matches the approximate value T ₁ ′. The control means controls the heater or the high-temperature medium supply means and the low-temperature medium supply means, and the approximate value T ₁ ′ is regarded as the steel plate temperature. As a result, the steel plate temperature can be measured quickly and accurately without being affected by variations in emissivity and changes with time of the steel plate to be measured and the reflecting plate.
T ₁ ′ = T _r + K (T _r −T ₂ ) ——Expression (1)
Here, K is a correction coefficient based on estimated values of the emissivities of the reflector and the steel plate to be measured, which are obtained from separate measurements or literature values.

  Hereinafter, the reason for the above configuration will be described in detail.

The present inventors have found that by merely temperature control by providing a heating means or cooling means on the rear surface of the reflector quickly to the target value of the temperature T ₂ of the reflector (i.e., the approximate value T ₁ of the steel plate temperature ') can not be brought close to, inevitably deviation between the temperature T ₂ of the reflective plate and the equivalent temperature T _r is revealed that occur. It has also been found that this deviation is an impediment when obtaining the temperature of the steel sheet quickly and accurately using a first order approximation. Therefore, the flow path on the back surface of the reflector plate is provided, a good response reflectors by utilizing the passage, and uniformly heated, if adopting a structure for cooling the target value the temperature T ₂ of the reflector The idea was that it would be possible to quickly approach (that is, the approximate value T ₁ ′ of the steel plate temperature). As a result, the temperature of the steel sheet can be measured quickly and accurately, coupled with the effect of speeding up the calculation when using the primary approximation formula.

  Next, by using the steel plate temperature measuring apparatus according to the present invention, it is theoretically possible to quickly and accurately measure the steel plate temperature without being affected by variations in emissivity and aging of the steel plate and the reflector. I will explain the support.

The radiance of the steel plate and the reflecting plate which are two finite flat plates (hereinafter, when the number of times the radiant energy radiated from each of the steel plate and the reflecting plate is reflected between the reflecting plate and the steel plate is 1 or 2 times) ) Will be expressed as the following equations (11) and (12) when the background radiation from the periphery of the two finite plates is ignored.

Here, F ₁₂ and F ₂₁ are a shape factor from the steel plate to the reflecting plate and a shape factor from the reflecting plate to the steel plate, respectively, and are values determined from the geometric shapes and positional relationships of the steel plate and the reflecting plate.

When E (T ₁ ) is obtained by eliminating the reflectance G _{2 of the} reflector from the above equations (11) and (12), the following equation (13) is obtained, and the equation for obtaining the black body radiant energy of the steel plate is obtained. It is done.

Here, K is a correction coefficient defined by the following formula (14) and determined from the emissivities of the steel plate and the reflecting plate.

Here, when both F ₁₂ and F ₂₁ are substantially equal to 1, equation (13) is simplified to the following equation (15) by setting F ₁₂ = F ₂₁ = 1.

Further, there is a relationship of G ₁ = σT _g ⁴ between the steel sheet's emissivity G ₁ and the temperature of a black body that emits energy equivalent to this (hereinafter referred to as “ejectivity temperature”) T _g . Therefore, the following equation (16) is derived from the above equation (15), and the steel plate temperature T ₁ can be calculated from the emissivity temperature T _g and the reflector plate temperature T ₂ as the equivalent temperature T _r .

From the above equation (16),
T ₁ ⁴ = (1 + K) T _g ⁴ −KT ₂ ^{4
_{= T g 4 + K (T}} g 4 -T 2 4)
^{_{= T g 4 [1 + K}} (1- (T 2 / T g) 4)]
Furthermore, if T ₂ / T _g = a,
T ₁ ⁴ = T _g ⁴ [1 + K (1-a ⁴ )]
= T _g ⁴ [1 + K (1-a) (1 + a) (1 + a ² )]
If a ≒ 1, then
T ₁ ⁴ ≈T _g ⁴ [1 + 4K (1-a)]
It becomes.

Therefore,
T ₁ ≈T _g [1 + 4K (1-a)] ^1/4
It becomes.

Here, when b≈0, (1−b) ⁴ = (1−4b + 6b ² −4b ³ + b ⁴ ) ≈ (1−4b), so that 1−b≈ (1−4b) ^1/4 Become. This relationship is applied to the above equation.

Therefore,
T ₁ ≈T _g [1 + K (1-a)]
= T _g [1 + K (1-T ₂ / T _g )]
_{= T g + K (T 2} -T g)
Thus, by replacing T ₁ with T ₁ ′, the above equation (1) is derived.

Here, K is a correction coefficient composed of a function of only the emissivities ε ₁ and ε ₂ of the steel plate and the reflecting plate, as shown in the above formula (14). For this reason, the correction coefficient K itself is affected by the emissivity fluctuations of the steel plate and the reflector, but the reflector temperature T ₂ is made to coincide with the emissivity temperature T _g (that is, the reflector temperature T _2. Is controlled so as to coincide with the above approximate value T ₁ ′ of the steel plate temperature, the error due to the correction coefficient K is excluded, and the steel plate temperature can be measured with high accuracy.

Therefore, the correction coefficient K does not need to be set strictly, but has a certain degree of accuracy because it affects the time required for the measured steel plate temperature to reach a predetermined accuracy. For this reason, as the estimated values of the emissivities ε ₁ and ε ₂ of the steel plate and the reflector, for example, values measured separately off-line or average values in the range of fluctuations assumed from literature values are adopted, and these values are used. What is calculated by substituting into the above equation (14) may be used as the correction coefficient K.

Moreover, in the steel plate temperature measuring device according to the present invention, since the flow path is provided on the back surface of the reflector, the reflector temperature T ₂ is matched with the approximate value T ₁ ′ of the steel plate temperature. By utilizing this flow path, the reflector can be heated and cooled uniformly with good responsiveness. Therefore, the difference ΔT between the reflection plate temperature T ₂ and id temperature T _g short time can be brought close to zero. Therefore, Id temperature T _g and the approximate value of the steel sheet temperature T _{1 'coincides} with naturally short time. That is, the approximate value T ₁ ′ of the steel plate temperature can be regarded as the steel plate temperature T ₁ . As described above, the steel plate temperature measuring apparatus according to the present invention can quickly and accurately measure the steel plate temperature without being affected by variations in emissivity and changes with time of the steel plate and the reflector.

In the temperature measuring apparatus for steel sheets according to the present invention, the explanation on the theoretical support that the steel sheet temperature can be measured quickly and accurately without being affected by fluctuations in emissivity and changes with time of the steel sheet and the reflecting plate is as follows. The radiant energy radiated from each of the reflecting plate and the reflecting plate is described using the emissivity when the number of times of reflection between the reflecting plate and the steel plate is 1 or 2, but is not particularly limited to this. . For example, instead of the above-mentioned emissivity, it is also possible to use the radiant energy from the steel plate when the radiant energy radiated from each of the steel plate and the reflecting plate is multiple-reflected between the reflecting plate and the steel plate. By employing the multiple reflection temperature T _m is the temperature of a black body that emits radiant energy equivalent energy in the case of the multiple reflection in the equivalent temperature T _r, the formula (1) can be directly applied.

Moreover, the shape of the flow path provided on the back surface of the reflector is not particularly limited, but a plurality of partition walls provided so as to be in contact with the back surface of the reflector and the back surface of the reflector are opposed to each other. It is preferable that the back plate is provided with a supply port to which the low temperature medium or the high temperature medium is supplied and a discharge port to be discharged on the back plate side. By doing in this way, a reflector can be heated and cooled uniformly with sufficient responsiveness. Moreover, it comprises so that the relationship between the thickness T of a reflecting plate, the space | interval W between several partition walls, and the thickness H of a partition wall, and height L may satisfy | fill following formula (2), (3). Thus, since the reflecting plate can be heated and cooled uniformly with good responsiveness, the temperature deviation ΔT in the reflecting plate can be set to a predetermined value or less, which is more preferable.
2 ≦ W / T ≦ 10 ――― Formula (2)
1 ≦ L / H ≦ 20 ――― Formula (3)
In such a configuration, the supply port is provided in the vicinity of the central portion of the flow path, the discharge port is provided on both ends of the flow path, and the low temperature medium or the high temperature medium is supplied from the vicinity of the central portion. It is preferable that the gas flow is directed toward the both end portions. By doing so, the cooling ability and heating ability of the low temperature medium and the high temperature medium can be maintained, so that the temperature can be controlled for each small area in the reflector. As a result, as described above, the temperature deviation ΔT in the reflecting plate can be set to a predetermined value or less.

  The shape of the reflector is not particularly limited, and various shapes such as a rectangle and a circle can be used.

  In the above description, the case where a high-temperature medium is used as the heating unit has been described. However, the present invention is not particularly limited thereto. For example, a heater may be provided in the flow path. In particular, if an electric heater is used, special equipment is not required and controllability is good.

  In the above description, the case where a low-temperature medium is used as the cooling unit has been described. However, various low-temperature media can be used and are not limited to specific ones. For example, in addition to cooling with a low temperature gas, air cooling, water cooling, or the like can be used. However, if cooling with a low temperature gas is performed, not only the controllability is good, but also the apparatus can be made relatively inexpensive, which is advantageous.

  Hereinafter, embodiments of a temperature measuring apparatus for steel sheets according to the present invention will be described with reference to the drawings.

FIG. 1 is a conceptual diagram for explaining the measurement principle of a temperature measuring device for a steel plate according to an embodiment of the present invention. FIG. 2 is a view showing a flow path provided on the back surface of the reflector shown in FIG. FIG. 3 is a block diagram showing a schematic configuration of a temperature measuring apparatus for a steel plate of the present embodiment, and FIG. 4 shows the relationship between the position in the reflector shown in FIG. 3, the cooling gas temperature, and the reflector temperature. FIG. 5 is a characteristic diagram showing another flow channel configuration provided for comparison with the flow channel shown in FIG. 3 and its characteristics. FIG. 6 is a schematic diagram for explaining the detailed specifications of the flow channel shown in FIG. FIG. 7 is a characteristic diagram showing the relationship between the detailed specification of the flow path shown in FIG. 6 and the temperature deviation in the reflector. FIG. 8 is the flow rate of the cooling gas flowing through the flow path of this embodiment, the electric heater output and the steel plate temperature. FIG. 9 is an explanatory diagram for explaining a flow path according to another embodiment of the present embodiment. As shown in FIG. 1, a reflecting plate 2 is provided in parallel with the steel plate 1. Since the reflection plate 2 can reduce the measurement error by increasing the shape factors F ₁₂ and F ₂₁ in the above formula (13) as much as possible and approaching 1, the shape factor is maximized with the same reflection plate area. It is desirable to install the reflecting plate 2 parallel to the steel plate 1 and as close as possible. However, since the steel plate 1 may wave up and down (wavy), it is necessary to install the steel plate 1 with a predetermined interval so that the steel plate 1 does not contact the reflection plate 2.

  Further, the radiation thermometer 3 is installed from the gap between the reflector 2 and the steel plate 1 toward the surface of the steel plate 1 so that the emissivity of the steel plate 1 can be received, and is emitted from each of the steel plate 1 and the reflector 2. The installation angle θ of the radiation thermometer 3 with respect to the steel plate 1 is adjusted so that the number of times the radiant energy is alternately reflected between the reflecting plate 2 and the steel plate 1 is 1 or 2 respectively. The reason why the number of reflections of the radiant energy between the reflector 2 and the steel plate 1 is at least once each is that when the radiant energy is received by the radiation thermometer 3 without being reflected by the reflector 2 once, Radiation energy from the background, such as the inner wall of the furnace, is directly reflected by the steel plate 1 and becomes part of the radiance of the steel plate 1 (reflected energy), so that the measurement error increases, but the reflection plate 2 reflects it at least once. This is because the influence of the radiant energy from the background becomes small enough to be ignored by reflecting the steel plate 1 afterwards, and the measurement error becomes sufficiently small. Also, the reason that the number of reflections of the radiant energy between the reflector 2 and the steel plate 1 is at most twice is that the influence of the radiant energy from the background is already sufficiently small even if it is reflected three times or more. This is because the effect of improving the measurement error is small, and the reflector 2 becomes larger instead.

  The installation angle θ of the radiation thermometer 3 with respect to the steel plate 1 is such that the size of the reflector 2 and the steel plate 1 are such that the number of reflections of radiant energy between the reflector 2 and the steel plate 1 is 1 or 2 respectively. May be adjusted as appropriate according to the distance between the reflector 2 and the reflecting plate 2, etc., taking into account the equipment restrictions such as the installation space of the radiation thermometer 3, etc. Therefore, it may be adjusted as appropriate in the range of 5 ° or more and less than 60 °, further 10 to 50 °, and particularly 20 to 40 °.

Moreover, the relationship between the radiation energy measured with the radiation thermometer 3 and the emissivity of the steel plate 1 is represented by the following equation.

That is, when F _g = ε _r , G ₁ = E _r . Therefore, by setting an emissivity ε _r corresponding to the form factor F _g from the steel sheet 1 to the radiation thermometer 3 in the radiation thermometer 3, a black body that emits energy equivalent to the emissivity G ₁ of the steel sheet 1 is set. It is translated at id temperature T _g in the radiation thermometer 3 as equivalent temperature T _r corresponding to the temperature is output.

Since the shape factor F _g from the steel plate 1 to the radiation thermometer 3 is determined from the geometric shape and positional relationship between the two and the directional emissivity of the steel plate 1, it can be theoretically determined. For example, it can be determined experimentally in the same geometric shape and positional relationship offline.

  In FIG. 2, reference numeral 4a denotes a partition wall provided in a substantially vertical state on the back surface of the rectangular reflector 2 and substantially perpendicular to the longitudinal direction of the reflector 2, and 4b is substantially perpendicular to the partition wall 4a. And it is the partition wall provided in the edge part side of the reflecting plate 2. FIG. The flow path 8 is composed of a plurality of reflectors 2, partition walls 4 a and 4 b, and a back plate 5 (see FIG. 3 described later). As shown in FIG. 2, an electric heater 20 (shown by a broken line) is disposed in the flow path 8 from the end to the end of the back surface of the reflection plate 2 in the longitudinal direction of the flow path 8. In addition, the flow path 8 is parallel to the electric heater 20, and from the center of the flow path 8 (to be precise, the supply port 6 side shown in FIG. FIG. 3 schematically shows a state in which a cooling gas 50 (shown by a solid line, see FIG. 3 for details) flows as a low-temperature medium toward the outlet 7 side shown in FIG.

  Like the schematic cross section of the flow path 8 depicted in the block diagram of FIG. 3, the back plate 5 having a U-shaped cross section is disposed so as to face the back surface of the reflector 2. This makes it possible to form a large number of short and small-sized flow paths 8 that are close to the back surface side of the reflecting plate 2. Moreover, since the apparent area of the back surface of the reflecting plate 2 is increased, the heating and cooling capabilities are substantially improved. The flow path 8 is connected to a cooling gas supply port 6 at a position corresponding to the vicinity of the center of the back surface of the reflector 2 and a cooling gas discharge / electric heater 20 at positions corresponding to the vicinity of both ends. It is also possible to provide a discharge port 7 that also serves as a space.

  In FIG. 3, 25 is a power source for an electric heater, 30 is a control means, 40 is a thermocouple as a temperature detector for directly measuring the temperature of the reflector 2, 50 is a cooling gas, 55 is a solenoid valve, and 56 is a regulator. , 60 is a steel plate temperature calculation circuit. The electric heater 20 is connected to the electric heater power supply 25, and the inside of the flow path 8 is heated by a command from the control means 50, and the temperature of the reflector 2 rises. Further, the electromagnetic valve 55 as the low temperature medium supply means is opened by a command from the control means 50, and the cooling gas 50 is supplied from the supply port 6 near the center and flows through the flow path 8, and from the discharge ports 7 near both ends. Discharged. Thereby, the inside of the flow path 8 is cooled, and the temperature of the reflecting plate 2 falls. Further, since the solenoid valve 55 is provided with the regulator 56, the flow rate of the cooling gas 50 can always be kept constant.

Next, the operation of the steel plate temperature measuring apparatus according to this embodiment will be described below. In the initial operation of the apparatus, for example, the initial set temperature of the reflecting plate 2 may be set to the target temperature T ₀ of the steel plate 1, for example. In this case, since there is a large temperature difference between the initial set temperature (target temperature T _{0 of the} steel plate 1) and the reflector plate temperature T ₂ measured by the thermocouple 40, the control means 50 changes the power to the electric heater power supply 25. A command is sent, and the inside of the flow path 8 is rapidly heated by the electric heater 20. Thereafter, the reflector temperature T ₂ that has been actually measured by the thermocouple 40 and the emissivity temperature T _g output from the radiation thermometer 3 are input into the steel plate temperature calculation circuit 60 and calculated based on the above equation (1). Then, an approximate value T ₁ ′ of the steel plate temperature T ₁ is calculated. This approximate value T ₁ ′ is used in the control means 50 as the target set temperature of the reflector 2 thereafter. Thereafter, heating is continued by the electric heater 20 until the approximate value T ₁ ′ matches the reflector temperature T ₂ . As a result, close to the reflective plate temperature T ₂ and id temperature T _g difference between ΔT is gradually reduced 0, reflector temperature T ₂ and the approximate value T _{1 'when} the match, the approximate value T _1' a regarded as a steel sheet temperature _{T 1.} However, when the reflection plate temperature T ₂ has exceeded the Id temperature The T _g, the steel plate temperature calculation circuit approximation T ₁ calculated in the 60 _'is newly controlled as the set temperature of the target of the reflector 2 Set in the means 30. As a result, a command to open the electromagnetic valve 55 is sent from the control means 30, and the cooling gas 50 is immediately caused to flow into the flow path 8 from the supply port 6 in the vicinity of the center, and cooling is started. Therefore, the difference ΔT between the reflector temperature T ₂ and the emissivity temperature T _g quickly approaches 0, and the reflector temperature T ₂ and the approximate value T ₁ ′ match. Thus, the steel sheet 1, without being affected by variation and aging of the emissivity of the reflection plate 2, so that the steel sheet temperature T ₁ of quickly and accurately measured.

  In the case of FIG. 4, the cooling gas 50 is supplied into the flow path 8 from the supply port 6 near the center and discharged from the discharge ports 7 near the both ends. And the volume is small, and it can be seen that the temperature rise of the cooling gas 50 in the flow path 8 is small. Therefore, it can be seen that the temperature distribution in the reflector 2 is also small, which is preferable as compared with the configuration of the flow path 100 shown in FIG.

  The flow path 100 shown in FIG. 5A can be configured only by using a back plate 90 having a U-shaped cross section instead of the back plate 5 shown in FIG. In this configuration, the cooling gas 50 is supplied from one end side of the back surface of the reflecting plate 2 and discharged from the other end side, so that the length of the flow path 100 is approximately twice the length of the flow path 8. The temperature rise of the cooling gas 50 in 100 is slightly larger than that in the flow path 8. Therefore, although the effect of cooling the reflecting plate 2 is sufficient, it is somewhat larger than the temperature distribution (see FIG. 4) in the reflecting plate 2 having the flow path configuration as shown in FIG.

  Next, FIGS. 6 and 7 show the results of studies on the detailed relationship between the detailed specification of the flow path 8 of the present embodiment shown in FIG. 3 and the temperature deviation ΔT (° C.) in the reflector 2. FIG. 6 is a schematic side cross-sectional view of the flow path 8 as seen from the longitudinal direction of the reflector 2 with the partition wall 4b removed. In FIG. 7A, the horizontal axis is the interval (W) between the partition walls 4a / the thickness (t) of the reflector 2, the left side of the vertical axis is the temperature deviation ΔT (° C.) in the reflector 2, and the right side of the vertical axis. Is the capacity index (−) of the electric heater power supply 25. In FIG. 7B, the horizontal axis indicates the height (L) / the thickness (H) of the partition wall 4a that contributes to substantially constituting the flow path 8 in the partition wall 4a, and the vertical axis. The left side is the temperature deviation ΔT (° C.) in the reflector 2, and the right side of the vertical axis is the capacity index (−) of the electric heater power supply 25.

  In FIG. 7A, it can be seen that if the interval (W) between the partition walls 4a is reduced, the temperature deviation ΔT in the reflector 2 is reduced. However, there is a practical limit to the size of the interval (W) between the partition walls 4a. It can also be seen that the temperature deviation ΔT in the reflecting plate 2 decreases as the thickness (t) of the reflecting plate 2 increases. However, when the thickness (t) of the reflecting plate 2 is increased, the capacity of the electric heater power source 25 necessary for heating the reflecting plate 2 is increased, and the cost of the apparatus is increased. In order to achieve the object of the present invention, the temperature deviation ΔT in the reflector 2 shown in FIG. 7A is preferably 1 ° C. or more and 10 ° C. or less. It can be seen from FIG. 7A that W / t is preferably 2 or more and 10 or less to realize this. In FIG. 7B, it can be seen that if the substantial height (L) of the partition wall 4a is reduced, the temperature deviation ΔT in the reflector 2 is reduced. However, there is a practical limit to reducing the substantial height (L) of the partition wall 4a. It can also be seen that the temperature deviation ΔT in the reflector 2 decreases as the thickness (H) of the partition wall 4a increases. However, as in the case of the thickness (t) of the reflector 2, if the thickness (H) of the partition wall 4 a is increased, the capacity of the electric heater power supply 25 required for heating increases, and the device The cost will be high. It can be seen that L / H is preferably 1 or more and 20 or less in order to realize the temperature deviation ΔT in the reflection plate 2 shown in FIG.

8 (a) is, if the steel sheet temperature T ₁ of becomes temporarily high, in order to explain how keep a reflector 2 in the how to any given temperature, the cooling gas 50 flowing through the flow path 8 flow rate, the output of the electric heater 20 shows the respective behavior of the steel sheet temperature T ₁ of the reflector temperature T _2. Thus if the steel sheet temperature T ₁ of becomes temporarily high, simply decrease the output of the electric heater 20, or, only to zero, the reflection plate 2 is subjected to radiant heat from the steel plate 1, The reflector 2 cannot be maintained at an arbitrary constant temperature. However, a small amount of cooling gas 50 corresponding to the amount of radiant heat from the steel plate 1 is always allowed to flow using the regulator 56, and the remainder adjusts the output of the electric heater 20 (see FIG. 8A). if) way, the steel plate temperature T ₁ is also turned temporarily high, it is possible to keep the reflective plate 2 to any constant temperature. Thus, as the steel sheet temperature T ₁ of it more quickly and accurately measured.

FIG. 8 (b), when dropped from constant high temperatures there is a steel sheet temperature T _1, the reflective plate temperature T ₂ in the how to explain how lower following the steel sheet temperature T _1, the flow path the flow rate of the cooling gas 50 flowing in the 8, the output of the electric heater 20 shows the respective behavior of the steel sheet temperature T ₁ of the reflector temperature T _2. Thus when dropped from the temperature constant high there is a steel sheet temperature T _1, simply decrease the output of the electric heater 20, or, only to zero, the reflection plate 2 is radiant heat from the steel sheet 1 and the reflector 2 since there is a heat storage amount of itself, it can not be lowered a reflector temperature T ₂ rapidly. However, in such a case, not only the small amount of cooling gas 50 corresponding to the amount of radiant heat from the steel plate 1 is always allowed to flow, but also the amount of heat stored in the reflector 2 itself, and the steel plate If the cooling gas 50 corresponding to a magnitude that can be rapidly lowered to the temperature T ₁ is further increased, the reflector temperature T ₂ can be lowered following the steel plate temperature T ₁ . For this purpose, the solenoid valve 55 may be opened by a command from the control means 30 so that the flow rate of the cooling gas 50 can be supplied at a plurality of levels.

  In this embodiment, as shown in FIG. 2, the rectangular reflector 2, the flow path 8 composed of the partition walls 4a and 4b and the back plate 5, and the rectangular reflector as shown in FIG. Although the example using the flow path 100 comprised from the board 2, the partition walls 4a and 4b, and the backplate 90 was demonstrated, it is not specifically limited to this. For example, as shown in FIG. 9, a disk-shaped reflecting plate 200, a cylindrical partition wall 210a provided substantially perpendicular to the outer periphery of the reflecting plate 200, and the reflecting plate in contact with the partition wall 210a A partition wall 210b provided in a substantially vertical state on the diameter of 200, a partition wall 210c orthogonal to the partition wall 210b, and provided so as to extend from the partition wall 210a substantially parallel to the partition wall 210c. Various forms such as a flow path 300 constituted by the partition wall 210d formed and a back plate (not shown) disposed so as to face the back surface of the reflection plate 200 are conceivable. In the present embodiment, the example in which the electric heater 20 is used as the heater has been described. However, the present invention is not necessarily limited thereto.

It is a conceptual diagram for demonstrating the measurement principle of the temperature measuring apparatus of the steel plate of the Example of this invention. It is the plane schematic diagram which showed the flow path provided in the back surface of the reflecting plate shown in FIG. 1 in the state which removed the back plate. It is a block diagram which shows schematic structure of the temperature measuring apparatus of the steel plate of a present Example. It is a characteristic view which shows the relationship between the position in a reflecting plate shown in FIG. 3, cooling gas temperature, and reflecting plate temperature. It is a characteristic view which shows another channel structure provided in order to compare with the channel shown in FIG. 3, and its characteristic. It is a schematic diagram for demonstrating the detailed specification of the flow path shown in FIG. It is a characteristic view which shows the relationship between the detailed specification of the flow path shown in FIG. 6, and the temperature deviation in a reflecting plate. It is a characteristic view which shows each behavior of the flow volume of the cooling gas sent through the flow path of an Example, an electric heater output, steel plate temperature, and reflector temperature. It is explanatory drawing for demonstrating the flow path of another form of a present Example.

Explanation of symbols

1: Steel plate 2, 200: Reflector plate 3: Radiation thermometers 4a, 4b, 210a, 210b, 210c, 210d: Partition wall 5, 90: Back plate 6: Supply port 7: Discharge port 8, 100, 300: Flow path 20: Electric heater 25: Electric heater power supply 30: Control means 40: Thermocouple 50: Cooling gas 55: Solenoid valve 56: Regulator 60: Steel plate temperature calculation circuit

Claims (6)

A reflecting plate installed opposite to the steel plate to be measured and provided with a flow path, a heater provided in the flow path or a high-temperature medium supply means for flowing a high-temperature medium in the flow path, and the flow path A low temperature medium supply means for flowing a low temperature medium, a heater or a control means for controlling the high temperature medium supply means and the low temperature medium supply means, and the temperature of the reflector (hereinafter referred to as “reflector temperature”). ) and a temperature detector for measuring T ₂ directly, the said angle radiant energy emitted from each of the measured steel sheet wherein the reflector is a predetermined number of reflections between the reflecting plate and the object to be measured steel plate the installed toward a measurement steel as the energy the emitted from the measured steel plate at this angle is measured and the equivalent temperature T corresponding to the temperature of a black body that emits the measured energy equivalent energy A radiation thermometer for by outputting converted into the following formula (1) from said measured steel sheet temperature (hereinafter. Referred to as "steel plate temperature") and the steel plate temperature calculation circuit for calculating an approximate value T _{1 'of} the Prepared,
The flow path is provided on a surface of the reflector opposite to the steel plate to be measured (hereinafter referred to as “back surface”), and the reflector temperature T ₂ matches the approximate value T ₁ ′. The temperature measurement of the steel sheet, wherein the heater or the high temperature medium supply means and the low temperature medium supply means are controlled by the control means, and the approximate value T ₁ ′ is regarded as the steel plate temperature. apparatus.
T ₁ ′ = T _r + K (T _r −T ₂ ) ——Expression (1)
Here, K is a correction coefficient based on estimated values of the emissivities of the reflector and the steel plate to be measured, which are obtained from separate measurements or literature values. The measured energy is an emissivity when the number of times the radiant energy radiated from each of the steel plate to be measured and the reflecting plate is reflected between the reflecting plate and the steel plate to be measured is 1 or 2 times. , and the said equivalent temperature T _r is the temperature measuring device of the steel sheet according to claim 1, wherein the id temperature the T _g determined in terms of the temperature of a black body that emits the id equivalent energy. The measured energy is the radiant energy from the measured steel plate when the radiated energy radiated from each of the measured steel plate and the reflecting plate is multiple-reflected between the reflecting plate and the measured steel plate. 2. The temperature measurement of a steel sheet according to claim 1, wherein the equivalent temperature T _r is a multiple reflection temperature T _m obtained by converting into a temperature of a black body that radiates energy equivalent to the radiation energy in the case of multiple reflection. apparatus. The flow path includes the reflection plate, a plurality of partition walls provided so as to be in contact with the back surface of the reflection plate, a back plate provided so as to face the back surface of the reflection plate, and the back plate side. The heater comprises a supply port through which the low-temperature medium or the high-temperature medium is supplied and a discharge port through which the medium is discharged. The heater is an electric heater, and the electric heater is disposed over the entire area of the flow path. The relationship between the thickness t of the reflector and the interval W between the plurality of partition walls and the thickness H and the height L of the partition walls satisfy the following expressions (2) and (3): The temperature measuring device for a steel sheet according to any one of claims 1 to 3, wherein
2 ≦ W / t ≦ 10 ――― Formula (2)
1 ≦ L / H ≦ 20 ――― Formula (3)   The supply port is provided in the vicinity of the central portion of the flow path, the discharge port is provided on both ends of the flow path, and the low temperature medium or the high temperature medium flows from the vicinity of the central portion toward the both end portions. The steel plate temperature measuring device according to claim 4 configured.   The steel plate temperature measuring device according to claim 5, wherein the low temperature medium is a low temperature gas, and the flow rate of the low temperature gas can be supplied from the low temperature medium supply means at a plurality of levels according to a command from the control means.

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