JP2939313B2 - Temperature detector for heater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a temperature detecting device for detecting a temperature of a heater for heating various objects.

[Prior Art] The heaters as described above are used in various industrial fields. Among them, for example, a heater used in a thermal analyzer is not simply heating an object, that is, a sample, but raising or lowering the temperature to a predetermined temperature accurately according to a certain program. Required. In this case, it is necessary to detect the actual temperature of the heater and control the amount of power supplied to the heater based on the detection result.

Conventionally, it is already known that there is a temperature detector using a thermocouple as a means for detecting the temperature of a heater. In this device, a temperature measuring point of a thermocouple is arranged near a heater to be measured. However, in the conventional apparatus, the temperature measuring point of the thermocouple is merely located near the heater, and no measure is taken to keep the distance between the two thermocouples constant. , Both were able to move independently.

[Problems to be Solved by the Invention] Generally, the positions of the heater and the thermocouple may be shifted during operation. For example, when an inert gas or the like is flowed around the heater, the heater may be moved by the gas flow. Also, when vibration is applied to a device including a heater, for example, a thermal analyzer, the heater inside the device may move. It is also conceivable that the thermocouple itself deforms and moves due to thermal expansion due to high temperature. In such a case, as described above, if the heater and the thermocouple can be freely and independently moved, the distance between the temperature measuring point of the thermocouple and the heater varies,
As a result, accurate temperature detection may not be possible.

In particular, when the operation of contacting or separating the thermocouple and the heater is repeated, the temperature detection result may be significantly disturbed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in the conventional apparatus, and has a constant temperature measurement point of a thermocouple and a constant temperature between a heater so that accurate heater temperature detection can always be performed. An object of the present invention is to provide a heater temperature detecting device.

Means for Solving the Problems In order to achieve the above object, a temperature detecting device according to the present invention is arranged such that a temperature measuring point of a thermocouple is arranged near a heater to detect the temperature of the heater. , A fixed line connecting the heater and the thermocouple to each other is provided, and the fixed line is made of the same material as one of two materials constituting the thermocouple; The pair of temperature measuring points and the heater are connected by the fixed line.

In the temperature detecting device for a heater having the above configuration, the thermocouple is formed of two kinds of materials, W-Re25% and W-Re3%, and the fixed wire is formed of W-Re25% or W-Re3%. Can be.

In the heater temperature detecting device having the above-described configuration, the heater can be formed by a mesh heater, and the fixed line can be joined or hooked to a stitch of the mesh heater.

[Operation] According to the heater temperature detecting device of the present invention, the heater and the temperature measuring point of the thermocouple are always kept at a fixed interval by a fixed line. Accordingly, even when one or both of the heater and the thermocouple fluctuates, the relative positional relationship between the two does not change, and thus accurate temperature data can always be obtained.

Further, the fixed wire is made of the same material as one of the two materials constituting the thermocouple, and the temperature measuring point of the thermocouple and the heater are connected by the fixed wire. The temperature can be directly led to the thermocouple through the fixed wire, so that the heat flow can be stabilized and the influence of disturbance can be reduced compared to the case where the temperature is measured through a gas atmosphere. Thus, more accurate temperature detection is possible.

According to the temperature detecting device of the second aspect, the thermocouple is connected to the W-Re25
% And W-Re3%.
Temperature detection can be performed even when the temperature of the heater is as high as 2400 ° C. or more. Also, by forming the fixed wire from W-Re25% or W-Re3%, that is, the same material as the thermocouple, extremely accurate temperature detection is possible.

Embodiment FIG. 1 shows an embodiment of a heater temperature detecting device according to the present invention. The heater 1 shown here is constituted by a mesh heater formed in a substantially cylindrical shape. The heater 1 is used to heat various objects, and when it is used in a thermal analyzer, it is used, for example, by a method as shown in FIG.

The device shown in FIG. 2 is a so-called differential thermal balance device (TG-
DTA device) with a heater incorporated. In the figure, a sample holder 2 is placed at a position surrounded by a heater 1. The sample holder 2 is supported on a balance 4 via a column 3. Two sample dishes 5 and 6 are placed on the sample holder 2. One sample dish, for example, the sample dish 5 contains a standard substance, and the other sample dish 6 contains a measurement sample. .

The standard substance and the measurement sample are heated by the heater 1 that generates heat based on a predetermined program. Then, at that time, the temperature difference between the standard substance and the measurement sample, that is, so-called differential heat, is measured, and at the same time, the weight fluctuation of the sample is measured by the balance 4.

In FIG. 2, reference numeral 7 denotes a furnace wall, and reference numeral 8 denotes a reflector for preventing radiation of radiant heat.

As described above, the heat generation from the heater 1 is controlled according to a predetermined program according to the measurement purpose. Hereinafter, a configuration for the control will be described.

Returning to FIG. 1, a thermocouple 9 is provided near the heater 1. The heat generated by the heater 1 is 2400 ° C.
Assuming the case where the temperature becomes extremely high as described above, for example, the one with W-Re25% on the minus side and W-Re3% on the plus side is used. The temperature measuring point 9a of this thermocouple is arranged near the heater 1, and the measuring point 9a is connected to the heater 1 by a fixed line 10. The fixed wire 10 is made of one of the materials constituting the thermocouple 9, for example, W-Re25%, and has one end welded to the thermocouple measurement point 9a as shown in FIG. The other end is joined to the stitch of the heater 1,
Or have been hooked.

The temperature of the heater 1 is detected by the thermocouple 9, and a temperature detection signal at that time is sent to the control circuit 12 via the insulating circuit 11. The control circuit 12 stores in advance a heating program corresponding to the measurement purpose, and compares the sent temperature detection signal with the heating program. The control circuit 12, based on the comparison result,
The current control circuit 14 disposed in the power supply circuit 13 for the heater 1 is controlled to control the current flowing into the heater 1. Thus, the amount of heat generated from the heater 1 is controlled.

In FIG. 2, an inert gas may be sent from the outside into the furnace wall 7 in order to stabilize the reaction of the measurement sample. In this case, the heater 1 swings by the gas flow. The heater 1 may also move when some force is applied to the furnace wall 7. further,
The thermocouple 9 itself may be deformed by thermal expansion. As described above, when the heater 1 or the thermocouple 9 relatively moves, conventionally, the heater 1 and the thermocouple temperature measuring point 9a
In this embodiment, the interval between the heater 1 and the thermocouple 9 is always kept constant by the fixed wire 10. There is no variation in temperature detection, and as a result, accurate temperature control can be performed by the heater 1.

Particularly, in the present embodiment, a thermocouple material of W-Re 25% is used as the fixed wire 10 and is connected to the thermocouple temperature measuring point 9a, so that the accuracy of temperature measurement is further improved.

Note that an insulating circuit 11 is provided between the thermocouple 9 and the control circuit 12. The insulation circuit 11 is connected to a control circuit 12 via a thermocouple 9 through a current flowing through the heater 1.
Flow, that is, in order to prevent the thermoelectromotive force generated in the thermocouple 9 from being disturbed by the heater current,
The formation of a closed circuit via the heater 1 and the thermocouple 9 is insulated.

As described above, the present invention has been described with reference to one embodiment, but the present invention is not limited to the embodiment.

The main purpose of the fixed wire 10 is to keep the distance between the thermocouple temperature measuring point 9a and the heater 1 constant. Therefore, the material and the mounting position on the thermocouple 9 are limited as long as the purpose is achieved. Can be changed arbitrarily. For example, a metal other than the thermocouple material can be used. Further, the material is not limited to a conductive material, and may be an insulating material. further,
It is also possible to connect to another place other than the thermocouple measurement point 9a.

As shown by the dashed line in FIG. 2, the sample dishes 5 and 6 are covered with a vacuum chamber 20, and the measurement is carried out with the vacuum pump 21 holding the vacuum inside the vacuum chamber 20, that is, around the sample dishes 5 and 6. You may be asked. In such a case, the present invention can be applied.

[Effect of the Invention] According to the first aspect of the present invention, since the distance between the temperature measuring point of the thermocouple and the heater is always kept constant by the fixed line, the heater temperature can always be accurately detected. Became possible.

In addition, the temperature of the heater can be directly led to the temperature measuring point of the thermocouple, so that more accurate temperature detection can be performed.

In particular, when temperature detection is required in a vacuum environment, there is no conduction by gas convection in a vacuum, so in a conventional temperature detection device, a large temperature difference occurs between a heater and a thermocouple temperature measuring point, Therefore, accurate temperature detection of the heater could not be performed. On the other hand, according to the present invention, the temperature of the heater can be directly led to the temperature measuring point of the thermocouple independently of the convection of the gas. became.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of a temperature detecting device according to the present invention, FIG. 2 is a sectional side view of a main part of a differential thermal balance device as an example of use of the temperature detecting device, and FIG. It is a side view which shows the principal part of a figure. 1 ... heater 9 ... thermocouple 9a ... thermocouple temperature measuring point 10 ... fixed wire 11 ... insulation circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01K 7/02 H05B 3/00

Claims (3)

(57) [Claims] 1. A temperature detecting device for locating a temperature measuring point of a thermocouple near a heater and detecting the temperature of the heater.
A fixed line connecting the heater and the thermocouple to each other is provided, and the fixed line is made of the same material as one of the two materials constituting the thermocouple, and A heater temperature detecting device, wherein a temperature measuring point and the heater are connected by the fixed line. 2. The thermocouple according to claim 1, wherein said thermocouple is W-Re25.
% And W-Re3%, and the fixed line is formed by W-Re25% or W-Re3%. 3. The heater temperature detecting device according to claim 1, wherein the heater is a mesh heater, and the fixed line is joined or hooked to a stitch of the mesh heater.