DD213292A1 - METHOD FOR THE TOOL-FREE MEASUREMENT OF THE TEMPERATURE AND A DEVICE THEREFOR - Google Patents

Abstract

Non-contact temperature measurement method and apparatus therefor, in particular for obtaining process information in metallurgy, with the aim of using a fully automated contactless temperature measurement with greater accuracy and reliability. The task is to obtain information about the temperature with variable and disturbing influencing factors on the test object and its surroundings with as little technical effort as possible. For this purpose, three measured values from different wavelengths are used in a multiply double ratio formation for determining the temperature according to the invention of N, starting from the Planckian radiation formula, whereby by subsequent linking with a characteristic and the analytical evaluation of determined emissivities in the corresponding wavelengths according to accuracy limits and validity criteria an automatic adaptation to the measuring conditions and after adaptive correction the representation of the temperature takes place. The apparatus developed for carrying out the method permits, via a decoding device, an arbitrary and defined assignment of the beam densities recorded in different wavelengths. The application of the invention relates to the entire field of metallurgy for the universal extraction of temperature and radiation information.

Description

Title of the invention

Method for the non-contact measurement of the temperature and a device thereto

Field of application of the invention

The invention relates to a method for non-contact measurement of the temperature and an apparatus therefor, in particular for obtaining process information in metallurgy.

Characteristic of the known technical solutions

For the non-contact measurement of the temperature, methods and devices are known (DE-CS 3031959), which allow the measurement of the temperature and spectral Pactors of DUTs by detecting and evaluating beam densities L in different wavelengths A. see and the Wien ^{1 given} radiation formula at m-Wellenlängena m equations with limiting conditions for the emissivity ε at the appropriate wavelength λ given, and for the determination of the temperature T is carried out on this basis, a simple quotient, which includes only two wavelengths in the required evaluation »

fs'i

On the other hand, the consideration of these "limiting conditions for" has elaborate methods of evaluation up to the provision of the information of the temperature to the pole.

Other disadvantages of the known methods and devices are that also the said additional expenses (DE-OS 3031959) and other arrangements to ensure the accuracy with läullpunktkontrollen (DD-PS 104623) or assignment of a comparison spectrum (DD-PS 147719) only are suitable for specific measuring conditions and an application under the changing conditions of measurement in metallurgy, as for example, by disturbing influence on the flow of radiation from the surface and environment of the object to be measured with slag in the metallic casting stream or scale on Walzadern, smoke, dust and flame development are not allowed.

Among these disturbing factors, which are subject to fluctuations in time, especially in metallurgy, the necessary measuring accuracy can not be achieved with the hitherto known solutions, in particular for tasks of process control and for increased demands on the quality of the products.

The devices used also have disadvantages when used under the measurement conditions of metallurgy, in particular the use of Ums ehalte devices for pivoting mirror (DD-PS 148985) in the optical measuring channel is unsuitable and affects the reliability of the temperature measurement ·

Object of the invention

The aim of the invention is to ensure the non-contact measurement of the temperature fully automatically and with higher accuracy, in particular under the conditions of metallurgy.

Explanation: the essence of the invention

The invention has for its object to provide a method for non-contact measurement of temperature and a device to develop that allow, with the least possible technical effort information about the temperature at variable and disturbing factors influencing the DUT and its surroundings, especially under the conditions of Metallurgy, fully automatic and with high accuracy *.

According to the invention, the non-contact measurement of the temperature T by a ratio formation with measured values of the converted into electrical signals beam densities L in different wavelengths A including the corresponding radiance of the black body 1 and the respective emissivity B ₇ ^ and a computing element is solved in that starting from N detected beam densities L = f (λ, Τ) = S (Λ, T) L ₃ (Λ, T)

with L (Λ, Τ)

^C 1

[exp

χ Τ where C ₁ , C ₂ = Planck's radiation constants

L = radiance of the black body at the. Wavelength λ.

represent, from the different wavelengths ? i,. _v

J, J, A

in each case three consecutively following measured values i, j, k of the radiance L (7l _i * k »^ ii ^) ^üt) a multiple double ratio formation the measuring signal

L (A ₁ , T) L (A _k , T)

2ζ. _

Jj IA · « j

D, and on the assumption that £ (^ ₁ , T) · £ (^, Τ) = £ ² (λ .., Τ)

and the distance of the differences between the wavelengths Δ7ν is equal, the true temperature T_. , _v out

is determined and by M measurements a mean, gewiehtete temperature T ^f . * _{v is} determined, v / elehe with the

-L, J, A

following the same process steps "determined temperature 2 ', vT according to the context

D being a parameter with which the accuracy limit and the validity of the measurement can be checked and according to the measurement conditions automatically determines the necessary number of measurements and non-compliance with predetermined characteristics D repeats the measurement process, while adhering to the characteristic D.

a mean temperature I »+ T ¹

, j, j ,,

is provided which applies a final true temperature can be ver or by determining the Snissionsgrade £ (λ.., _Ί, Τ) in the WellenlängenbereichenΆ .. _ * _v>

-L, J, K, A Ι, ^, ϋ ,, Χ

a correction of the temperature T on the basis of the relationship

i, i, i, i \ · ^a * - ³ ii, ki ⁺ ^ ₁ ) Ai ^{+ Λ} · ° i, j, k, i ^{+ d} >

wherein the constants a, b, c and d by a third order solution approach of Porm

be determined and thus the conditions

and £ ² (? L _k , I) = c5 U ₃ .,!) δ (A ₁ , T)

evaluated analytically and su an adaptive correction of the temperature Ü? and for showing the temperature T leads. Furthermore, the degrees of finite degree ε (Λ. _. _V -,) can be used as

continuous use of process information ·

According to the invention, an apparatus for carrying out the method of "non-contact temperature measurement with an optical imaging device, a rotating filter disk with a drive motor for detecting the beam densities L in the different wavelengths α, a photoelectric conversion and a Eechenglied constructed so that _s with a decoder any defined Assignment of the highly selective filters of the rotating filter disk is achieved by signals which are obtained via a photoelectric receiver, an amplifier with a downstream analog / digital converter and multiplexer, which is coupled on the one hand with a control device which monitors the operating state of the drive motor and the other by connection with a computing device and downstream output and input unit allows the automatic display of the results of the temperature measurement on display and also via a coupling and memory purity ensures direct further processing of temperature and radiation information with analog and digital signals for process control ·

The particular advantage of the method and the device according to the invention is that the non-contact measurement of the temperature is fully automatic with reasonable effort and the adaptation to all DUTs by changing the highly selective filter in the sensitivity

"Range of the photoelectric receiver allows a universal application and further the required accuracy and adaptability is selectively influenced according to the requirements and variable Mess." conditions on DUT and the environment »The invention thus creates a crucial prerequisite for the rational use of a non-contact temperature measurement and their effective use for information gathering in process automation, especially under the sometimes extreme environmental conditions in metallurgy,

embodiment

The invention will be explained below with reference to an exemplary embodiment.

Pig. 1 shows the device for carrying out the method of non-contact temperature measurement.

The solution according to the invention is based on that of a DUT, for example, of a cast strand in the steel mill, dis radiance L (7i, T) in 4 different wavelengths Λ -, ο., . is detected.

This results in the determination of the temperature in subsequent process steps

Starting from the relation L (ά, Τ) = £ (7ί, T) L ₃ (Λ, T)

with I (A, T) = - * -. -

2

C) - 17y

where CL, Gp = Planck ¹ see radiation constant L = radiance of the black body

at the wavelength λ.

6 = degree of transmission

will represent on the assumption that

and the distance Δ Λ. between the wavelengths is constant, a multiple double ratio formation first at the wavelengths / * ..., A ₂ and A, symbolically represented A _{1 2} 3 »carried out and a measurement signal K _{1 o} ο according to

, T) L (Λ-, Τ) L (A T) L (A-, T)

¹ ' ² ' ³ L ² (Tl ₂ , T) - determined L ² .

L ² (Tl ₂ , T) - L _S

Under the prerequisites already mentioned, the true temperature T _{1 o} -5 is obtained by means of the Wien'-see and Planck's radiation formula

^{C (} J

^T 1,2,3

1,2,3 TO

T _{1 o} -, is the temperature which at the wavelengths A _- ,

2 '3 is determined. Ifach same procedure is at the wavelengths 7L ₂ , λ. ", Λ., The temperature ¹ ^ ₂ 3 4 determined

Make a number of measurements M, given, for example, as a function of the measurement object and variable measurement conditions with M = 10, T \ _o -j and T ^f _o «-

a weighted averaging determined and linked to a parameter D according to / Τ'- ₉ «-Τ ' _Λ -,> ι / - D ·

D represents a parameter with which the accuracy limit and the validity of the measurement is checked and the necessary number of measurements is determined automatically according to the measuring conditions. "If the predetermined characteristic D is adhered to, the entire measuring process is repeated, and if the parameter D is maintained a mean temperature T off

1,2,3 ^{τ χ} 2,3,4

¹ 2 -

provided as the final true temperature ·

For higher specified accuracy requirements, the temperature ¥ is corrected by determining the emissivities 6 (Tt _{1. 0} ^ λ> ϊ) i £ at the wavelengths Tl ₁ <~>"\ a

based on the context, 2,3,4 '

' ^{T) = a7v} - ³ 1,2,3,4 ⁺ ^ ² 1,2,3,4 ^{+ C} N, 2,3,4

The constants a, b, c and d are determined by a third order solution approach with:

L (TL ₁ JT) =

L (T1 ₂ , T) = _{222 32}

L (tu, T) β (a7v ^ -5 + b ^ ² o + c7i- + d) L (7l-, f)

L (Ti _4, T) = (aa ³ ₄ + b ^ ² ₄ + ₄₊ C7L d) L ₃ (Ti ₄₁ T)

Thus, an analytical evaluation is performed after ^{2 2} 0i ₂ , T) = £ (71. ,, T) f (Tt ₃ , OJ) and

ε ² Ci ₃ , τ) ~ £ (Ti ₂ , τ) £ (a ₄ , -i)

and leads to an adaptive correction of the temperature T and thus to the temperature T.

The emissivities £ (7L _{1 o} ^ _Ai T) can become independent

Obtaining process information, "for example, for the determination of the quality of the molten steel used.

According to the invention, the solution for such a basic procedure according to the in Pig. illustrated device, wherein the beam flow of a measurement object, for example a cast strand in the steelwork, continuously impinges on an optical imaging device (1). By a rotating filter disc (2), which consists of K (K ^ 4) highly selective filters and by a drive motor (3 ), the spectral decomposition in the wavelengths Λ _{Λ o} r> _{A is} possible because a decoding unit

direction (4) an arbitrary and defined assignment of the beam densities L in the wavelengths Tl. ",. for the after-

following processing of the beam densities allowed. Accordingly, in a subsequent photoelectric receiver (5) the optical signals are converted into an electrical quantity and fed via an amplifier (6) to an analog / digital converter with a downstream multiplexer (8). This is coupled to the control unit (9) and the Computing device (10) via the input and output unit (11) an output via screen (12) and an output for the direct process coupling via the coupling and memory unit (13) allowed »via the output and output unit (11) For example, the specifications for the characteristic D and the number of measurements M at the beginning of the measurement »The use of the decoder (4) and the corresponding control options, resulting from the link with the multiplexer (8), the control unit (9), the drive motor (3) and the arithmetic unit (10), allows an arbitrary and defined assignment in the measurement of the beam _densities L _71- . Thus, the universal application of the device is ensured while maintaining the basic process steps.

Furthermore, the bin-channel processing of the device is an essential prerequisite for high accuracy and reliability at the same time reasonable technical effort with special attention to the use of microelectronic assemblies, In addition, a further adaptation to the measurement conditions can be achieved by the possibility of replacing the highly selective filter for the measurement of the radiances L in the wavelengths A _{1 o} -, _Ai so that, for example, the

usability can be considerably extended in the production of process information from the flame of a metallurgical process, such _s for example over the course of the blowing process in the carbon combustion, while maintaining the individual process steps, and the output of the information is matched with the target position. Furthermore, it should be emphasized that the illustrated inventive advantages of the method and the device to the adaptation to the measurement conditions with high accuracy, in particular by the adaptive procedure, for. B, the temperature correction is made possible, so that, for example, disturbances on the object of measurement, caused by slag content and other impurities in a metallic pouring stream, scale deposits on a rolling stock or impairments of the optical transmission of the stream of radiation due to the development of smoke and flames can be compensated.

Furthermore, the solution according to the invention allows 'direct coupling with process automation systems, so that the high-accuracy over-the-clock information directly influences decisive indicators of material and energy economy, quality and performance increase.'

Claims (4)

Erfindungaanspruch 1, J, & D is a parameter with which the accuracy limit and the validity of the measurement can be checked and according to the measurement conditions automatically determines the necessary number of measurements and non-compliance with predetermined characteristic D repeats the measurement process, while maintaining the characteristic D a mean temperature φ t r φ t T = is provided, which can be used as the final true temperature or by the determination of the emissivities ε (λj _ · _v ι »ϊ) ⁱⁿ äen wavelengths A ₄ ^ _v ι Ij J, Ä, X 1, J _t JS. _t X a correction of temperature ¥ based on the context ikl ^{+ c7x} iik - | Jj -Κ ·, X X, J, ii :, is realized in further method steps, wherein the constants a, b, c and d by an approach 3 · order of the form be determined and thus the conditions analytically evaluated and led to an adaptive correction of the temperature Ψ and to the representation of the temperature T · 1, J, Jt 1, J, Js. over a multiple double ratio formation the measurement signal L OT) L (T) 1. A method for non-contact measurement of temperature and a device thereto by a ratio formation with measured values of the converted into electrical signals radiance L in different wavelengths λ. including the corresponding radiance of the black Body L _n and the Eüiissionsgrades £ at the respective s Wavelength and a computing element characterized in that starting from Έ detected beam densities L = f (71, T) = € (Tl ", T) L ₃ (A, T) with ^C 1 L (λ, T) = (-Tjp.) - 17 from the different wavelengths A 3 in each case. following measurements of the radiance L (ά · _v »^ · - v) 2 * Method according to item 1, characterized in that the determined degrees of suction ε (A, _Ί ) and their course X, J, iC, X used to obtain additional process information * 3. Apparatus for carrying out the method with an optical imaging device, a rotating filter disk with drive for detecting the beam densities L-Λ. in different wavelengths, a photoelectric wall length and a computing element, characterized by,. daJS'die highly selective filter of the rotating filter disc (2), which is moved by the drive motor (3), with a decoder (4) arbitrarily defined the arrangement is assigned, consisting of the photoelectric receiver (5) j an amplifier (6) nachgeschalt et em analog / digital converter (7) and multiplexer (8), which is coupled to a control device (9) and a computing device (10) and via a downstream output and input unit (11) the display of the temperature T and Smoothing degree ε on a display (12) allows and at the same time on the coupling and memory unit (13) further processing for process automation is possible. , 3, ₂ is obtained and thus on condition that £ ( ⁷ ^ ₁ * T) E { A _k , T) = £ ² (Λ., T) is the distance of Differences between the wavelengths is equal, the true temperature in is determined and by M measurements a mean, weighted temperature T'_. , , it is determined which Temperature T ¹ . _{v Ί} according to the context J, £, X »- φ» 4. Apparatus for carrying out the method according to item 3 », characterized in that an adaptation to the measuring conditions of the test object is ensured by interchangeable filter, To do this, 1 soap drawings