JPH0473092B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the temperature of a tubular object in a furnace.

A radiation thermometer is used to non-contactly measure the temperature of a tubular object, such as a steel pipe, inside a heating furnace or heat treatment furnace.The conventional measurement method using this radiation thermometer is as shown in Figure 1. A radiation thermometer 4 looks through the inner and outer surfaces of the steel pipe 1 in the furnace 2 through a transmission window 3 provided on the furnace wall, and detects the radiant energy from the surface of the steel pipe that falls within the field of view of the radiation thermometer 4. . The radiation thermometer 4 is of a scanning type whose measurement position can be changed. On the other hand, the steel pipe 1 that is transported inside the furnace 2 in a direction perpendicular to the tube axis direction is placed at an appropriate position in the furnace width direction depending on the length of the steel pipe 1 so that the steel pipe 1 can be transported within the furnace without any problems. It is loaded into the furnace so that it is placed on the ground. That is, since the distance between the end of the steel pipe 1 and the inner surface of the furnace side wall varies depending on the length of the steel pipe 1, the position (distance from the pipe end) of the temperature measurement point (indicated by 5 in the figure) on the steel pipe will vary depending on the length of the steel pipe.
Further, when the outer diameter or inner diameter of the steel pipe 1 changes, the measurement boundary point (indicated by 7 in the figure) between the inner surface and the outer surface changes. Therefore, such a temperature measuring method has the problem that the measured temperature cannot correspond to the measured position, and it is also impossible to distinguish between the inner surface and the outer surface of the steel pipe.

In heat treatment such as hardening and tempering of steel,
It is well known that the temperature history of the material to be treated and the soaking temperature during the heat treatment process greatly affect quality such as mechanical strength, and during heat treatment of steel pipes, both the longitudinal direction and the inner and outer surfaces of the steel pipe are kept within the required temperature range. It is important to carry out heating and soaking, that is, uniform heat treatment, to obtain uniform quality with little variation. However, with the conventional temperature measurement method mentioned above,
Since the temperature distribution corresponding to the position in the tube axis direction and the temperature difference between the inner and outer surfaces cannot be determined, the necessary operations for uniform heat treatment such as controlling the heating soaking time and controlling the temperature distribution in the length direction of the steel tube can be performed quickly and accurately. I couldn't do it.

The present invention provides a temperature measurement method to solve such problems, and its gist is to look through a window provided in the furnace wall into the inner surface or inner and outer surfaces of one end side of a tubular object in the furnace. The temperature on one end of the tubular object is scanned and measured by a radiation thermometer installed at a position on the tubular object, and the temperature is calculated using the dimensions of the tubular object at the time of the measurement and a value representing the installation conditions of the radiation thermometer. This method of measuring the temperature of a tubular object is characterized in that temperature measurement information corresponding to the temperature measurement position is obtained based on the correspondence between the temperature measurement position and the scanning angle of the radiation thermometer.

The present invention will be explained in detail below based on the illustrated embodiments.

FIG. 2a is a diagram showing the configuration of an apparatus in an embodiment of the present invention. In the figure, 4 is a radiation thermometer that scans the measurement field of view angle range θ, and measures the furnace 2 corresponding to the angle θ.
It is possible to measure the temperature of the inner and outer surfaces of the steel pipe 1 inside. 11 is a temperature measurement signal circuit that converts the detection signal of the radiation thermometer 4 into a temperature signal, and 12 is a temperature measurement signal circuit that converts the detection signal of the radiation thermometer 4 into a temperature signal. This is a scanning angle signal circuit that calculates the scanning angle corresponding to the angle α of . Reference numeral 13 denotes a setting device that determines the distance L ₁ between the temperature measuring side end 6 of the steel pipe 1 in the furnace 2 and the inner surface of the furnace side wall.
(Determined by the length of steel pipe 1), outer diameter D of steel pipe 1
and the wall thickness t are also input.

In addition, 14 is a setting device, which is the installation condition of the radiation thermometer 4, H (relative height to the steel pipe 1), L ₂
(horizontal distance from the inner surface of the furnace side wall), α (reference inclination angle), and L ₀ max (distance at which the temperature can be measured on the outer surface of the steel pipe, which is restricted by the installation conditions of the radiation thermometer 4) are input.

15 is an arithmetic circuit, and the set values L ₁ , D, H, L ₂ , α, L ₀ max from the setting devices 13 and 14 are
Using the scanning angle range (±θi) for temperature measurement on the inner surface of the steel pipe 1 and the scanning angle range (+θ ₀ ) for temperature measurement on the outer surface of the steel pipe 1 shown in FIG. The following formula (-θi) = tan ^-1 {(H-t)/(L ₁ +L ₂ )}-α
...(1) (+θi) = α−tan ^-1 {(H−D+t)/(L ₁ +L ₂ )}
……(2) (+θ ₀ )=(α−θi)−tan ⁻¹ {(H−D)/(L ₀ max
+L ₁ +L ₂ )} ...(3), and when the angle signal (±θa) from the scanning angle signal circuit 12 is within the angle range (±θi) or (+θ ₀ ), the corresponding This is an internal/external temperature determination circuit that outputs a determination signal.

16 divides the temperature signal from the temperature measurement signal circuit 11 into an inner surface temperature signal and an outer surface temperature signal based on the discrimination signal of inner surface temperature measurement or outer surface temperature measurement from the inner and outer surface temperature measurement discrimination circuit 15. This is a temperature signal division circuit. In addition, 17 is also an arithmetic circuit,
The inner surface corresponding to the temperature measurement position (Li and L ₀ in Fig. 2 c) when each measurement position on the inner surface and outer surface of the steel pipe 1 is expressed as a distance from the steel pipe end 6 or 7. The scanning angle range (θ _ic ) and the outer surface scanning angle (θ _pc ) are obtained by the same calculation as in the arithmetic circuit 15, and are (θ _ic )=(−θ _i )+(+θ _i ).
and (θ _pc ) = (+θ _p ), and since the reference inclination angle α is set to zero, the scanning angle of the radiation thermometer (+
θ _a ) can be easily matched.

Inner surface scanning angles −θ _ic and +θ _ic and outer surface scanning angle θ _pc based on reference inclination angle α in Figure c.
The correspondence relationship between the inner surface temperature measurement position L _i and the outer surface temperature measurement position L ₀ is (4) when the scanning angle −θ _ic is within the range of (−θ _i ).
Formula, L _i = f (-θ _ic , L ₁ , α, L ₂ , H, D, t)
...(4) When the scanning angle +θ _ic is within the range of (+θ _i ), (5)
Formula, L _i = f (±θ _ic , L ₁ , α, L ₂ , H, D, t)
...(5) When the scanning angle θ _pc is within the range of (+θ _p ), (6)
It is obtained from the related expression L _p = f (θ _pc , (+θ _i ), L ₁ , α, L ₂ , H, D, t) (6). The values calculated by the arithmetic circuit 15 are used for (+θ _i ), (−θ _i ), and (+θ _p ). −θ _ic , +θ _ic , θ _pc in equations (4), (5), and (6) can be easily replaced with the scanning angle (±θ _a ) of the radiation thermometer as described above, and the scanning angle (±θ _a ) and temperature measurement positions (L _i and L _p ). This is a temperature measurement position signal circuit that converts the angle (±θ _a ) from the scanning angle signal circuit 12 into a temperature measurement position signal.

Reference numeral 18 denotes a temperature pattern measuring circuit that outputs a temperature signal from the temperature measuring signal circuit 11 based on the output from the temperature measuring position signal circuit 17 in association with a temperature measuring position and a measured temperature value. Furthermore, 19 calculates the maximum value, average value, and minimum value of each of the inner surface temperature and outer surface temperature from the temperature signal classification circuit 16, and calculates the maximum value, minimum value, and average value of the temperature difference between the inner surface and the outer surface. This is a temperature difference calculation circuit that outputs a temperature difference.

With the above configuration, even if the charging position of the steel pipe 1 into the furnace 2 changes depending on the length of the steel pipe, temperature values corresponding to each temperature measurement position on the inner and outer surfaces of the steel pipe 1 can be detected. It is also possible to calculate the temperature difference and temperature distribution between the inner and outer surfaces. Based on the temperature information calculated in this way, the operating conditions of the furnace can be accurately controlled.

Although the radiation thermometer 4 in the above embodiment is of a type with a built-in scanning function, it is of course possible to use a type of radiation thermometer that adjusts the angle of the entire thermometer. 13,14
L ₁ , D and t inputted from can also be automatically inputted from another process computer or business computer.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a conventional temperature measuring method, and FIG. 2 is a diagram illustrating an apparatus configuration in an embodiment of the present invention. 1: Steel pipe, 2: Furnace, 3: Transmission window, 4: Radiation thermometer, 11: Temperature measurement signal circuit, 12: Scanning angle signal circuit, 13: Setting device, 14: Setting device, 15: Inside and outside temperature measurement discrimination Circuit, 16: Temperature signal division circuit, 1
7: Temperature measurement position signal circuit, 18: Temperature pattern measurement circuit, 19: Temperature difference calculation circuit.

Claims (1)

[Claims] 1 Scanning and measuring the temperature at one end of the tubular object in the furnace using a radiation thermometer installed at a position that looks into the inner surface or inner and outer surfaces of one end of the tubular object in the furnace through a window provided in the furnace wall; The temperature measurement corresponding to the temperature measurement position is calculated based on the correspondence between the temperature measurement position on the tubular object and the scanning angle of the radiation thermometer, which is calculated using the dimensions of the tubular object and the value representing the installation conditions of the radiation thermometer. A method for measuring the temperature of a tubular object, characterized by obtaining temperature information.