JPS5812537B2 - Ondo Profiler - Yousoshi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an element for a temperature profiler, which allows rapid measurement of the temperature distribution along the axial direction of, for example, a tubular electric furnace.

Conventionally, when measuring the temperature distribution of an electric furnace or the like, one thermocouple was shifted along the measurement points and the temperature at each measurement point was measured.

Therefore, when moving a thermocouple from one measurement point to the next, there is a time lag for the thermocouple to reach a thermal equilibrium state, so if there are many measurement points, the measurement time will take a long time. Not only that, but the work was also cumbersome.

Therefore, the present invention provides a temperature profiler element that enables rapid temperature distribution measurement without the need to move the temperature sensing element. The resistance wires are arranged parallel to each other with their folding points sequentially shifted in the longitudinal direction, and the resistance wires are bundled while being insulated from each other.

The principle of temperature measurement using the device of the present invention will be explained below with reference to the drawings.

FIG. 1 shows, for example, a fictive temperature distribution in an electric furnace and a constant temperature bath provided adjacent to the electric furnace.

FIG. 2 shows a group of resistance wires for temperature measurement.

In Figure 2, R1, R2, R3... are resistance lines,
They are each folded in half at their midpoints XljX2, X3, . . . , and these resistance lines are parallel to each other, and the folding points XI+X2 y

Further, the ends (folding points) of these resistance wires are placed in a furnace, and both ends are placed in a constant temperature oven.

Now, let the resistance value of the nth resistance wire be R.

, two adjacent resistance lines R. , Ro, each midpoint XL
Xn-1 position fie△dn +n- 1, tonohe d
The difference in length between the resistance lines Rn and Rn-1 due to
The length of the nth resistance wire in the humidity chamber is 18n, and the length between the nth and nth resistance wires is 18n.
The difference in length of the first resistance wire in the thermostatic chamber is △Sn, n-1
Assuming that the oven, constant temperature bath, and resistance wire have reached thermal equilibrium, the resistance value of the resistance wire Rn can be expressed as follows.

In this equation, each term on the right side means the line integral of the resistivity outside the thermostatic chamber (inside the furnace) and inside the thermostatic chamber at the n-th resistance line, respectively.

The difference between the resistance value of the n-th resistance wire and the resistance value of the n-1th resistance wire can be approximated by assuming that Δdo,n-1 is small.

Here, 7 (T) is the interval Δdn,. 1, T is the average temperature at that location, and ρ8 is the resistivity in the thermostatic chamber.

However, in order for this formula to be effective, the resistance wires must be made of the same material and have uniform resistivity, and the temperature within the thermostatic chamber must also be uniform.

Generally, the resistivity of resistance wire is ρ1ρ.

+αT...It is expressed by the relationship (3).

ρ here. is the resistivity at zero degree C, and α is the temperature coefficient.

Therefore, equation (2) can be written as follows.

α here.

, α8 are the temperature coefficients of resistivity at Tn and Ts.

If we keep it, equation (4) becomes becomes.

α. If you choose a resistance wire material with =α3, you can obtain.

Therefore, if you cool the constant temperature bath with an appropriate cryogen, More T.

It is possible to find the temperature. That is, α, △1,
Since Ts is known in advance, it is sufficient to measure the difference in resistance value (ΔR).

Specifically, the difference in resistance value is extracted as an electrical signal and converted into temperature.

Note that, as is clear from equation (7), the lower T8 is, the larger ΔRn,n-1 becomes.

Therefore, it is desirable that the temperature of the constant temperature bath is low.

On the other hand, since α changes somewhat in any material depending on the temperature, it is better to use equation (6) as the basis for precise measurement.

In terms of the circuit, αs and Ts'Δl are stored, and α near the Tn temperature is stored.

must be compensated for.

In order to increase the accuracy of T, it is desirable to make △l small, but if that is the case, △Ro,n-1? Since the signal is weakened, it is desirable to find an appropriate value depending on the resistor.

Designed to satisfy I to Δ'nun 1-ΔSn,nt-, Δ1 is sufficiently large, Δ1o,.

−1, ΔSn,. If the resistivity of the parts other than - can be ignored, then △dn of the resistance wire.

Measurements can be made even if the changes in Rn and Ro-1 due to the temperature difference at -1 are small.

In a preferred embodiment of the present invention, resistance wires of equal length are folded in half and arranged in parallel with the folding points shifted at a constant interval (△d) in the longitudinal direction, and these resistance wires are electrically connected to each other. Examples include those that are insulated, bundled, and solidified into a rod shape with a substance that can be maintained at the temperature to be measured.

Note that the portion of these resistance wires corresponding to the inside of the thermostatic oven may have any shape.

Further, it is desirable to select the above-mentioned interval (Δd) and resistance wire material in accordance with the above-mentioned precautions.

In the device of the present invention, a plurality of resistance wires are sequentially shifted and bundled, so there is no need for the trouble of moving the temperature sensing device or the time lag that occurs each time the temperature sensing device is moved.

Therefore, temperature distribution measurement can be performed quickly.

In particular, it is convenient in combination with a device that automatically selects any two adjacent resistance lines and detects the difference in their resistance values.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the fictive temperature distribution in the electric furnace and a constant temperature chamber installed adjacent to it, and Fig. 2 is a diagram showing the fictive temperature distribution in the electric furnace and the constant temperature chamber installed adjacent to it. FIG. R,,R2,R3...Resistance line, XI + X2 tx
3...Midpoint of each resistance line, Δd1, 2...Resistance line R1
and R2 and the midpoint position difference, ls...the length of the resistance wire R in the constant temperature chamber, ΔS1,2...the difference in the length of the resistance wires R1 and R2 in the constant temperature bath.

Claims (1)

[Claims] 1. For temperature profiler use, a plurality of resistance wires of the same length are folded in half and arranged in parallel with their folding points sequentially shifted in the longitudinal direction, and these resistance wires are bundled while maintaining insulation from each other. element.