JPH10221178A - Thermocouple type temperature measuring equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate heat conduction and improve response, by inserting material for accelerating heat conduction into the part between a sheath accommodating a thermocouple and a well for protecting the sheath from outside. SOLUTION: Material 20 for accelerating heat conduction is inserted into a gap between a sheath 4 and a well 5. Low melting point metal whose coefficient of volume expansion at the time of solid is approximate to that at the time of liquid is preferably used as the material 20. When an object 17 of temperature measurement in a structure body 10 for the object, like a fluid tube, is fused metal or the like, it is desirable that the material 20 is metal of the same kind as the object 17. By inserting the material 20 for accelerating heat conduction, the temperature of a junction point (junction point for temperature measurement) in the seath 4 is changed by the heat traveling from the side surface of the well 5 through the material 20 and the sheath 4. The response can be improved as the result that the heat conduction path is minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermocouple-type temperature measuring device, and more particularly to a thermocouple-type temperature measuring device, in which responsiveness is enhanced by promoting heat transfer between a junction for temperature measurement and a side surface of a well. The present invention relates to a thermocouple-type temperature measuring device that can be improved.

[0002]

2. Description of the Related Art Generally, as shown in FIGS. 3 and 4, a thermocouple is formed by joining the tips of two types of metal wires 1 and 2 to each other by welding or the like, and forming a first junction 3 (for temperature measurement). And the other ends of the metal wires 1 and 2 are respectively connected by conducting wires (not shown) to form a closed circuit having second and third connection points (reference connection points). When the temperature of the first junction 3 is changed while keeping the temperature of the point constant, a thermoelectromotive force due to a temperature difference generated between the first junction 3 and the second and third junctions is used. In this case, the temperature is measured.

The thermocouple is usually housed in a housing tube called a sheath 4, and the sheath 4 is protected by a protection tube called a well 5 with a gap on the outside.

[0004] As shown in FIG.
An end cap 7 is fixed to the lower end of the hole by welding or the like. The well 5 is formed by drilling a drill hole 8 in a metal rod. The lower end of the end cap 7 is machined so that it can abut.

As shown in FIG. 3, the thermocouple is connected to a temperature measuring object 10 such as a fluid pipe from a nozzle 12 welded and fixed (welded portion 11) to a temperature measuring structure 10 such as a fluid pipe. The flange 13 at the rear end of the well 5 is welded to the end of the nozzle 12 with the tip inserted into the structure 10 for use (weld portion 14). .

A thread 15 is formed at the rear end of the well 5, and the sheath 4 is attached to the well 5 by screwing a sheath holding member 16 for holding the sheath 4 to the thread 15. It is made to let.

Reference numeral 17 denotes a temperature measuring object such as a fluid pipe which flows inside the temperature measuring object structure 10.

[0008]

However, the above-mentioned conventional thermocouple type temperature measuring device has the following problems.

That is, the temperature change at the first junction 3 is largely due to the heat transmitted from the lower end of the well 5 to the end cap 7 of the sheath 4, but the lower end of the well 5 and the first junction 3 The distance 18 between the first junction 3
(The distance 18 between the lower end of the well 5 and the first junction 3 is actually greater than the distance 19 between the first junction 3 and the side of the well 5). Distance 1 between
9 is almost two to three times higher), and thus the response was not sufficiently good.

The present invention has been made in view of the above circumstances, and provides a thermocouple-type temperature measuring device capable of improving responsiveness by promoting heat transfer between a temperature measuring junction and a side surface of a well. It is intended to provide.

[0011]

According to the present invention, there is provided a sheath for accommodating a thermocouple, and a well for protecting the sheath from the outside.
And a thermocouple-type temperature measuring device characterized in that a heat transfer promoting substance 20 is inserted between them.

In this case, the heat transfer promoting substance 20
However, a low-melting-point metal having a similar body expansion coefficient between a solid state and a liquid state may be used.

Alternatively, the space between the sheath 4 and the rear end of the well 5 may be closed by welding.

Further, according to the present invention, the enlarged diameter portion 22 is formed at the distal end portion of the sheath 4, and at least the position corresponding to the side surface of the junction 3 (the junction point for temperature measurement) of the thermocouple in the enlarged diameter portion 22. Is brought into contact with the side surface of the well 5.

According to the above means, the following effects can be obtained.

Since the heat transfer promoting substance 20 is inserted into the gap between the sheath 4 and the well 5, the joint 3 (temperature measuring contact point) in the sheath 4 is connected to the heat transfer promoting substance from the side of the well 5. The temperature is changed by the heat transmitted through the sheath 20 and the sheath 4, and the heat transfer path is shortest.
Responsiveness can be improved.

At this time, the material 20 for promoting heat transfer inserted into the gap between the sheath 4 and the well 5 is made of a low-melting-point metal. Then, the liquid of the low melting point metal and the sheath 4 or the well 5
And the like, thereby improving heat transfer performance and temperature measurement accuracy.

Further, by making the heat transfer promoting substance 20 inserted into the gap between the sheath 4 and the well 5 a low melting point metal having a similar body expansion coefficient between a solid state and a liquid state, the low melting point metal is converted from the solid state. When the phase changes to a liquid, there is no problem that the volume of the low melting point metal is increased and the sheath 4 and the well 5 are damaged.

Further, the rear end of the well 5, the sheath holding member 16 and the sheath 4 screwed to the screw portion 15 at the rear end of the well 5
Is closed by welding (welded portion 21), so that the heat transfer promoting substance 20 is
Is sealed in the well 5, and when the well 5 is broken, the temperature measurement object 17 is prevented from flowing out through the gap between the well 5 and the sheath 4 at the position of the welded portion 21. It becomes possible.

A bulged portion 22 is formed at the distal end of the sheath 4, and at least a position of the bulged portion 22 corresponding to the side surface of the junction 3 (temperature measurement junction) of the thermocouple is located in the well 5. When contact is made with the side surface, the junction 3 in the sheath 4 (the junction for temperature measurement) changes in temperature due to the heat transmitted from the side surface of the well 5 through the expanded portion 22 of the sheath 4. As a result, the responsiveness can be improved by the shortest heat transfer path.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention.

The basic structure of the thermocouple is shown in FIG.
Since the configuration is the same as that of FIG. 4, the same portions are denoted by the same reference numerals and description thereof will be omitted.

The present invention is characterized in that the heat transfer promoting substance 20 is inserted into the gap between the sheath 4 and the well 5.

The heat transfer promoting substance 20 inserted into the gap between the sheath 4 and the well 5 is preferably a low-melting-point metal having a similar body expansion coefficient between a solid state and a liquid state.

Further, the heat transfer promoting substance 20 inserted into the gap between the sheath 4 and the well 5 is used when the temperature measurement target 17 inside the temperature measurement target structure 10 such as a fluid pipe is a molten metal or the like. Is preferably made of the same kind of metal as the temperature measurement target 17.

For example, when the temperature measuring object 17 flowing inside the temperature measuring object structure 10 such as a fluid pipe is liquid sodium or the like used as a heat medium in a nuclear power plant or the like, the heat transfer is promoted. Sodium is used as the substance 20. In addition, sodium will be inserted in a solid state.

Here, sodium is a low melting point metal having a low melting point of 98 degrees Celsius, a body expansion coefficient of 0.9692 in a solid state, and a body expansion coefficient of about 0.9277 in a liquid state. is there.

Further, the rear end of the well 5, the sheath holding member 16 and the sheath 4 screwed to the screw portion 15 at the rear end of the well 5
Is closed by welding (welded portion 21).

Next, the operation will be described.

The process of measuring the temperature with the thermocouple is the same as in FIGS.

In the present invention, since the heat transfer promoting substance 20 is inserted into the gap between the sheath 4 and the well 5, the junction 3 (temperature measurement junction) in the sheath 4 is transferred from the side of the well 5. The temperature is changed by the heat transmitted through the heat-promoting substance 20 and the sheath 4, and the responsiveness can be improved by the shortest heat transfer path.

At this time, the material 20 for promoting heat transfer inserted into the gap between the sheath 4 and the well 5 is made of a low-melting-point metal. Then, the liquid of the low melting point metal and the sheath 4 or the well 5
And the like, thereby improving heat transfer performance and temperature measurement accuracy.

Further, by making the heat transfer promoting substance 20 inserted into the gap between the sheath 4 and the well 5 a low melting point metal having a similar body expansion coefficient between a solid state and a liquid state, the low melting point metal is converted from the solid state. When the phase changes to a liquid, there is no problem that the volume of the low melting point metal is increased and the sheath 4 and the well 5 are damaged.

Further, when the temperature measurement target 17 inside the temperature measurement target structure 10 such as a fluid pipe is a molten metal or the like, the heat transfer promoting substance 20 inserted into the gap between the sheath 4 and the well 5 is used. If the temperature measurement target 17 is made of the same kind of metal, even if the well 5 is damaged and the temperature measurement target 17 comes into contact with the heat transfer promoting substance 20,
Both do not react, and it is possible to maintain safety.

For example, when the temperature measurement object 17 flowing inside the temperature measurement target structure 10 such as a fluid pipe is liquid sodium or the like used as a heat medium in a nuclear power plant or the like, the heat transfer promotion If sodium is used as the substance 20, even if the well 5 is broken and the temperature measurement target 17 comes into contact with the heat transfer promoting substance 20, safety can be maintained.

Incidentally, sodium is a low melting point metal having a low melting point of 98 ° C., a solid expansion coefficient of 0.9692 in a solid state, and a body expansion coefficient in a liquid state of about 0.9277. In this case, it is most suitable to use as the heat transfer promoting substance 20.

Further, the rear end of the well 5, the sheath holding member 16 and the sheath 4 screwed to the threaded portion 15 at the rear end of the well 5
Is closed by welding (welded portion 21), so that the heat transfer promoting substance 2 is
0 is sealed in the well 5, and when the well 5 is broken, the temperature measurement object 17 is prevented from flowing out through the gap between the well 5 and the sheath 4 at the position of the welded portion 21. It is possible to do.

FIG. 2 shows a second embodiment of the present invention, in which the distal end portion of the sheath 4 is expanded into a deformed spherical shape or a water droplet shape to form an enlarged diameter portion 22.
Alternatively, at least the junction 3 of the thermocouple at the enlarged diameter portion 22
The position corresponding to the side surface of (the junction for temperature measurement) is in contact with the side surface of the well 5.

Even in this case, the joining points 3 in the sheath 4
(Junction for temperature measurement) is from the side of the well 5 to the sheath 4
The temperature is changed by the heat transmitted through the enlarged diameter portion 22 of the slab, and the responsiveness can be improved by the shortest heat transfer path.

Except for the above, it has the same configuration as that of the above-described embodiment, and the same operation and effect can be obtained.

It should be noted that the present invention is not limited to only the above-described embodiments, and that combinations other than those described in the embodiments described above are also possible. Of course, various changes can be made within a range not to be performed.

[0043]

As described above, according to the thermocouple type temperature measuring device of the present invention, the responsiveness is improved by promoting the heat transfer from between the temperature measuring junction and the side surface of the well. It is possible to achieve an excellent effect of being able to do so.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of a first embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of a second embodiment of the present invention.

FIG. 3 is a schematic overall side view of a conventional example.

FIG. 4 is a partially enlarged sectional view of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Joining point 4 Sheath 5 Well 20 Heat transfer accelerating substance 21 Welded part 22 Expanded part

Claims (4)

[Claims] 1. A heat transfer promoting substance (20) is inserted between a sheath (4) containing a thermocouple and a well (5) protecting the sheath (4) from the outside. Thermocouple type temperature measuring device. 2. The heat-transfer promoting substance (20) is a low-melting-point metal having a similar body expansion coefficient between a solid state and a liquid state.
The thermocouple-type temperature measuring device as described in the above. 3. The thermocouple-type temperature measuring device according to claim 1, wherein the space between the sheath (4) and the rear end of the well (5) is closed by welding. 4. A swollen portion (22) at the distal end of the sheath (4).
A thermocouple type temperature measurement, wherein at least a position corresponding to the side surface of the junction (3) of the thermocouple in the enlarged diameter portion (22) is brought into contact with the side surface of the well (5). apparatus.