THERMOCOUPLE, TEMPERATURE MEASURING SYSTEM AND METHOD FOR PRODUCING A THERMOCOUPLE

Abstract

The present invention relates to a thermocouple (1) for measuring the temperature of a high-voltage component, having a metal first conductor (2) made of a first material and a metal second conductor (3) made of a second material, wherein the first material differs from the second material, wherein the first conductor (2) and the second conductor (3) are mechanically asymmetrical and electrically symmetrical with respect to one another. The invention also relates to a temperature measuring system (10) having the thermocouple (1) according to the invention and to a method for producing a thermocouple (1) according to the invention.

Claims

1. A thermocouple (1) for measuring the temperature of a high-voltage component, having a metal first conductor (2) made of a first material and a metal second conductor (3) made of a second material, the first material differing from the second material, characterized in that the first conductor (2) and the second conductor (3) are mechanically asymmetrical and electrically symmetrical with respect to one another.

2. The thermocouple (1) as claimed in claim 1, characterized in that the first conductor (2) has a higher resistivity than the second conductor (3) and the cross-sectional area of the first conductor (2) is greater than the cross-sectional area of the second conductor (3) by the factor, or substantially the factor, by which the resistivity of the first conductor (2) is higher than the resistivity of the second conductor (3).

3. The thermocouple (1) as claimed in claim 1, characterized in that the first conductor (2) consists of chromium nickel or iron, or predominantly chromium nickel or iron, and the second conductor (3) consists of nickel or copper nickel, or predominantly nickel or copper nickel.

4. The thermocouple (1) as claimed in claim 1, characterized in that a tubular first insulating sheathing (4) is formed at least partly around the first conductor (2), which is in particular configured in the form of a wire, and a tubular second insulating sheathing (5) is formed at least partly around the second conductor (3), which is in particular configured in the form of a wire.

5. The thermocouple (1) as claimed in claim 4, characterized in that at least partly around the first conductor (2), the second conductor (3), the first insulating sheathing (4) and the second insulating sheathing (5) there is formed a common third insulating sheathing (6).

6. The thermocouple (1) as claimed in claim 1, characterized in that the first conductor (2) and the second conductor (3) are at least partly twisted together.

7. The thermocouple (1) as claimed in claim 4, characterized in that an outer circumferential surface of the first insulating sheathing (4) lies at least partly against an outer circumferential surface of the second insulating sheathing (5).

8. The thermocouple (1) as claimed in claim 1, characterized in that the first conductor (2), the second conductor (3), the first insulating sheathing (4), the second insulating sheathing (5) and/or the third insulating sheathing (6) are flexibly configured.

9. A temperature measuring system (10) for measuring a temperature, having a thermocouple (1) as claimed in claim 1, an analog-digital converter (7) and a microprocessor (9) in signaling connection with the analog-digital converter (7).

10. A method for producing a thermocouple (1) as claimed in claim 1, having the following steps: providing the first conductor (2), with the first insulating sheathing (4), providing the second conductor (3), with the second insulating sheathing (5), at least partly twisting the first conductor (2), which is located within the first insulating sheathing (4), with the second conductor (3), which is located within the second insulating sheathing (5), and at least partly sheathing the twisted conductors (2, 3) with the third insulating sheathing (6).

Description

[0034] In the respective schematic figures:

[0035] FIG. 1 shows a sectional view of a thermocouple according to an embodiment according to the invention, and

[0036] FIG. 2 shows an equivalent circuit diagram for a temperature measuring system according to the invention.

[0037] Elements with the same function and mode of operation are each provided with the same reference signs in FIGS. 1 and 2.

[0038] In FIG. 1, a thermocouple 1 for measuring the temperature of a high-voltage component is schematically illustrated. The thermocouple 1 has a metal first conductor 2 made of chromium nickel and a metal second conductor 3 made of nickel. As can be seen in the sectional view in FIG. 1, the first conductor 2 has a greater cross-sectional area than the second conductor 3. As a result, the first conductor 2 and the second conductor 3 are mechanically asymmetrical with respect to one another. Nevertheless, as a result of the chosen metal pairing, the first conductor 2 and the second conductor 3 are electrically symmetrical with respect to one another. In the present example, the first conductor 2 made of chromium nickel has a higher resistivity than the second conductor 3 made of nickel, the cross-sectional area of the first conductor 2 being greater than the cross-sectional area of the second conductor 3 by the factor, or substantially the factor, by which the resistivity of the first conductor 2 is higher than the resistivity of the second conductor 3 to obtain an electrical symmetry that is as ideal as possible. Possible as a further metal pairing would be iron for the first conductor 2 and copper nickel for the second conductor 3.

[0039] As can also be seen in FIG. 1, the first conductor 2 and the second conductor 3 are in each case configured in the form of a wire with a round cross section. As a result, the first conductor 2 and the second conductor 3 are correspondingly flexibly configured. At the same time, a tubular first insulating sheathing 4 is formed around the first conductor 2 and a tubular second insulating sheathing 5 is formed around the second conductor 3. Furthermore, around the first conductor 2, the second conductor 3, the first insulating sheathing 4 and the second insulating sheathing 5 there is formed a common third insulating sheathing 6. That is to say that the third insulating sheathing 6 is in direct contact with the first insulating sheathing 4 and the second insulating sheathing 5, the first conductor 2 being kept at a distance from the third insulating sheathing by the first insulating sheathing 4 and the second conductor 3 being kept at a distance from the third insulating sheathing by the second insulating sheathing 5.

[0040] The first conductor 2 and the second conductor 3, including the respective insulating sheathing 4, 5, are twisted together with a single twist. An outer circumferential surface of the first insulating sheathing 4 in this case lies against an outer circumferential surface of the second insulating sheathing 5.

[0041] With reference to FIG. 1, a method for producing the illustrated thermocouple 1 or the portion according to the invention of the thermocouple 1 is to be described hereafter. In a first step S1, for this purpose the first conductor 2, with the first insulating sheathing 4, and the second conductor 3, with the second insulating sheathing 5, are provided. In a subsequent second step S2, the first conductor 2 in the first insulating sheathing 4 and the second conductor 3 in the second insulating sheathing 5 are twisted together. After that, the twisted conductors 2, 3, which are in the respective insulating sheathing 4, 5, are sheathed with the third insulating sheathing 6.

[0042] In FIG. 2, an equivalent circuit diagram of a temperature measuring system 10 for measuring a temperature on a high-voltage measurement object by means of the thermocouple 1 described above is illustrated. The temperature measuring system has for this purpose the thermocouple 1, an analog-digital converter 7 and a microprocessor 9 in signaling connection with the analog-digital converter 7. The microprocessor 9 is arranged such that it is electrically insulated from the analog-digital converter 7 by an insulation 8. As can be seen in FIG. 2, the first conductor 2 of the temperature measuring system 10 has a different electrical resistance than the second conductor 3.

[0043] Apart from the embodiments illustrated, the invention allows further configuration principles. That is to say that the invention should not be regarded as restricted to the embodiments illustrated in the figures.

LIST OF REFERENCE SIGNS

[0044] 1 thermocouple

[0045] 2 first conductor

[0046] 3 second conductor

[0047] 4 first insulating sheathing

[0048] 5 second insulating sheathing

[0049] 6 third insulating sheathing

[0050] 7 analog-digital converter

[0051] 8 insulation

[0052] 9 microprocessor

[0053] 10 temperature measuring system