JPS6049848B2 - Temperature measurement method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature measuring method and apparatus, and more particularly to a temperature measuring method and apparatus for non-contactly measuring the temperature of the surface of an object to be measured.

Conventionally, radiation thermometers, optical pyrometers, and two-color pyrometers are known as temperature measuring devices that non-contactly measure the surface temperature of an object to be measured.

However, although a radiation thermometer can accurately measure the temperature of a black body, it is necessary to know the emissivity of objects other than black bodies and perform temperature correction. Therefore, it is difficult to accurately measure temperature if the emissivity is unknown or changing. In addition, the land-type radiation thermometer is designed so that the error when the object to be measured is other than a black body is considerably small, and if the emissivity is between 0.6 and 1.0, the temperature will be approximately correct. Can be measured. However, in any of the above cases, there is a problem that the error becomes large when the emissivity is as small as 0.2 to 0.4, such as in cold-rolled steel sheets. Optical thermometers can accurately measure temperature when the object to be measured is a black body, but temperature correction must be made for objects other than black bodies, which causes the same problem as radiation thermometers. There is a point. In addition, the two-color pyrometer was created to reduce the temperature correction when the object to be measured is not a blackbody, as mentioned above, but it measures the ratio of the radiance at wavelength λ and wavelength λ2. The problem is that the radiation ratio (λ, /λ) must be known since it is a device that can be used to determine temperature. The present invention has been made to solve the above problems, and its first purpose is to provide a temperature measurement method that does not require temperature correction based on emissivity.

A second object of the present invention is to provide a temperature measuring device that does not require temperature correction based on emissivity, has a simple structure, and can be manufactured at low cost. A first object of the present invention is to arrange the radiant heat absorbing sides of a plurality of radiant heat absorbing objects that absorb radiant heat from the object to be measured at approximately the same distance from the object to be measured, and to absorb the radiant heat from the object to be measured. setting the radiant heat releasing side of the absorbing object to different thermal conditions, and detecting the temperatures of the radiant heat absorbing side and the radiant heat releasing side of the plurality of radiant heat absorbing objects;
This is achieved by measuring the temperature of the object to be measured from this detected temperature. A second object of the present invention is to provide a plurality of radiant heat absorbing objects that absorb radiant heat from the object to be measured, which are arranged approximately equidistant from the object to be measured; a temperature setting device for setting a thermal condition different from that of the radiant heat emitting side of the plurality of radiant heat absorbing objects; This is achieved by configuring the system to include an arithmetic device connected to each of the plurality of temperature detection devices and a temperature display unit connected to the arithmetic device. - Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, an embodiment of the temperature measurement method will be described. As shown in FIG. 1, radiant heat absorbing objects 4 and 6 are placed at equal distances from the surface 2 of the object to be measured. That is, the radiant heat absorbing objects 4 and 6 are made of, for example, ceramic, which absorbs radiant heat from the object to be heated, and are arranged so that the radiant heat absorbing sides 4a and 6a are located at equal distances from the surface 2 of the object to be temperature measured. has been done. The radiant heat emitting sides 4b and 6b of the radiant heat absorbing bodies 4 and 6 are set to different thermal conditions. To set different thermal conditions, for example, the radiant heat emitting side 4b may be heated and the radiant heat emitting side 6b may be cooled. Here, the temperature of the surface 2 of the object to be measured is TX
C'K], the temperature of the radiant heat releasing side 4b is T1 [ball], the temperature of the radiant heat absorbing side 4a is T2 [ball], the temperature of the radiant heat releasing side 6b is LC'K], the temperature of the radiant heat absorbing side 6a is If the temperature is T4 [ball], then the amount of heat transmitted from the surface 2 of the object to be measured to the radiant heat absorbing objects 4 and 6 is Ql, q2 [Kcal/! d-Hr
] is expressed as the following equations (1) and (2) assuming a steady state.

However, σ is the Stefan Boltzmann constant, φ1 and φ2 are constants determined by the emissivity and the positional relationship between the surface of the object to be measured and the radiation heat absorbing side of the radiant heat absorbing object, λa, λb
are the thermal conductivities [Kc
al/I・Hr・℃] and ΔV1ΔXb are the thicknesses [m] of the radiant heat absorbing bodies 4 and 6, respectively.

In the above equations (1) and (2), since the radiant heat absorption sides 4a and 6a are arranged so that the distances from the surface 2 of the object to be measured are equal, and the materials of the radiant heat absorption objects are the same, φ
1″-φ2, λa′.input b.

If we divide the sides of equations (1) and (2), we get the following (3)
It becomes like the expression. Here, if the right side of equation (3) is set to α, Tx is calculated as shown in equation (4).

In equation (4), α is the ratio of the temperature gradients of the radiant heat absorbing bodies 4 and 6 as shown on the right side of equation (3) (however, the thickness ΔX
(including the correction coefficient if a and Δoil are different), which is α half 1.

Therefore, as described above, it is necessary to set the radiant heat emitting sides 4b and 6b to different thermal conditions. Therefore, the temperatures T2, T4 on the radiant heat absorbing sides 4a, 6a of the radiant heat absorbing bodies 4 and 6, and the temperatures Tl, T3 on the radiant heat releasing sides 4b, 6b.
By detecting and using equation (4) above, it is possible to measure the temperature of the surface of the object to be measured. Note that if the thicknesses ΔXa and ΔX of the radiant heat absorbing object are different, it is necessary to further measure these thicknesses to obtain the above α. Furthermore, although the above description has been given of an example in which two radiant heat absorbing objects are used, the present method can be similarly applied even when three or more radiant heat absorbing objects are used. Further, although an example has been described in which the radiant heat absorbing objects are arranged at equal distances from the surface of the object to be measured, substantially the same effect can be obtained even if the radiant heat absorbing objects are arranged at substantially equal distances. Next, the temperature measuring device will be explained.

This measuring device directly utilizes the measuring method described above. An embodiment of this measuring device is shown in FIGS. 2 and 3.
As shown in FIG. 2A, the first temperature sensor 10 has a first radiant heat absorbing object 12 fitted into the open end of a first protection tube 11. The first radiant heat absorbing object 12 is formed into a cylindrical shape of silicon nitride or ceramic having a sufficiently small heat capacity, and is provided with a slit 13 for thermally insulating the radiant heat absorbing object 12 and the protection tube 11. (Fig. 2 A and B). Further, a temperature detection device 14 such as a thermocouple is embedded in the radiant heat absorbing side and the radiant heat releasing side of the first radiant heat absorbing object 12. This temperature detection device 14 is
It may be attached to the radiant heat absorbing side and the radiant heat emitting side. A heater 18 as a temperature setting device is provided on the radiant heat emitting side of the first radiant heat absorbing object 12 via a copper plate 16 for equalizing thermal conditions. Second
temperature sensor 1' is the second temperature sensor 10 in the same way as the first temperature sensor 10.
A second radiant heat absorbing object 12'', a slit 13'', a temperature detecting device 1C, and a copper plate 16'' are provided in the protective tube 1''. Further, the inside of the second protection tube 1 is divided by a partition plate 20, and cooling air 22 is circulated therein to constitute a temperature setting device.Therefore, the radiant heat releasing side of the radiant heat absorbing object is will be set to different thermal conditions.
The first and second temperature sensors are connected as shown in FIG. 3 to constitute a temperature measuring device.

As shown in the figure, the temperature sensors 10 and 1' are fixed to a fixing member 24 in parallel. A voltage regulator 26 for the heater 18 is connected to the temperature sensor 10, and a cooling air flow rate control valve 28 is connected to the temperature sensor 1'.
Note that 30 is a cooling air inlet, and 32 is a cooling air outlet. The temperature detection devices 14 and 1C of the temperature sensors 10 and 1'' are connected to a calculation device 36 via an electric wire 34. This arithmetic device is connected to the temperature display section 38. In this embodiment, as shown in FIG. 3, temperature sensors 10 and 1' are placed near the surface 2 of the object to be measured, and a voltage regulator 26 and a cooling air flow rate control valve 28 are adjusted to absorb radiant heat. Set different thermal conditions on the radiant heat emitting side of the object. Then, a temperature signal is output from the temperature detection devices 14 and 14'', and the arithmetic unit 36 calculates the above equation (4), and the calculation result is displayed on the temperature display section.Next, the radiant heat absorbing object is Ceramic (97% Al2O3) thickness 4W
r! n, and the inner diameter of the protection tube is 60? , the thickness of the copper plate is 0.5, the power of the heater is 0.1KW, the amount of cooling air is 2
．． FIG. 4 shows the response speed when the temperature measuring device of the present invention was made with a temperature of 5 d/Min.

The figure shows the response speed when measuring the temperature of a steel plate at a constant temperature of 800°C in the initial stage. Next, the response speed is shown when the temperature of the steel plate changes stepwise from 80CfC to 900900°C to 800°C, and when the temperature of the steel plate changes in a sine curve. The solid line in the figure shows the steel plate temperature, and the broken line shows the temperature indicated by the device. From this figure, the time constant of this temperature measuring device is approximately 0.5 mi.
It is n. Although this value is larger than that of a conventional radiation thermometer, it is comparable to that of a thermocouple used on the in-furnace thermometer side. Note that the accuracy can be increased by connecting a plurality of temperature detection devices provided on the radiant heat absorption side or the radiant heat emission side of the radiant heat absorbing object in series to expand the thermoelectromotive force.

This accuracy can be 0.5% or less. As explained above, according to the present invention, it is possible to obtain an advantageous effect that correction due to emissivity is unnecessary, the measurement temperature range can be set arbitrarily, and a device with a simple structure and low cost can be provided.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining one embodiment of the temperature measuring method of the present invention, FIG. 2 A is a sectional view of the temperature sensor section of the temperature measuring device of the present invention, and FIG. Figure 2 A (7) B-
3 is a block diagram showing one embodiment of the temperature measuring device of the present invention, and FIG. 4 is a diagram showing the response speed of the temperature measuring device. 2...Temperature measurement object surface, 4, 6, 12, 12''
...Radiant heat absorption object, 4a...Radiant heat absorption side, 4b...Radiant heat release side, 10,1'...
...Temperature sensor 5 sensor, 14,14''...Temperature detection device, 16,16''...Copper plate, 18...Heater, 36...Calculation device, 38...Temperature display section.

Claims (1)

[Scope of Claims] 1. The radiant heat absorbing sides of a plurality of radiant heat absorbing objects that absorb radiant heat from an object to be temperature measured are arranged at approximately equal distance from the object to be temperature measured, and the plurality of radiant heat absorbing objects absorb radiant heat from the object to be temperature measured. The radiant heat releasing side of the plurality of radiant heat absorbing objects is set to different thermal conditions, and the temperature of the radiant heat absorbing side and the radiant heat releasing side of the plurality of radiant heat absorbing objects is detected, and the temperature of the object to be measured is determined from the detected temperature. A temperature measurement method that measures . 2. A plurality of radiant heat absorbing objects that absorb radiant heat from the object to be measured, which are arranged approximately equidistant from the object to be measured, and radiant heat releasing sides of the plurality of radiant heat absorbing objects are placed under different temperature conditions. a temperature setting device to be set; a plurality of temperature detection devices provided in contact with the radiant heat absorption side and the radiant heat release side of the plurality of radiant heat absorption objects; and a temperature detection device connected to each of the plurality of temperature detection devices. A temperature measurement device configured to include a calculation device and a temperature display unit connected to the calculation device.