JPH0712652A - Sheath type thermocouple - Google Patents

Abstract

PURPOSE:To provide a sheath type thermocouple which has characteristic required for a sheath without losing profitability, strength and inherent characteristic thereof. CONSTITUTION:Charaterization is performed in that the inside of a sheath 1 composed of metal with which an end thereof is enclosed is filled with an insulator 2, a sheath type thermocouple which has buried a thermocouple element 3 in the inside of the insulator 2 has a small diameter part whose diameter is smaller than that of another part in part of the sheath 1, a cylinder part 4 composed of other metal different from the metal forming the sheath 1 is engaged with the small diameter part, the inside surface of the cylinder 4 closely adheres to the outside surface of the small diameter part and the outside surface of the cylindrical body 4 forms the same face as the outside surface of the sheath 1.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sheath type thermocouple.

[0002]

2. Description of the Related Art A sheath type thermocouple is provided with a sheath made of a metal having a sealed tip, an insulator filled in the sheath, and a thermocouple element embedded in the insulator. This sheath type thermocouple is used in a wide range of applications such as measuring the exhaust gas temperature of a jet engine in an aircraft.

For the sheath type thermocouple, the user selects the material of the sheath according to the environment in which the sheath type thermocouple is installed, such as temperature, humidity and atmosphere, and the performance required for the sheath type thermocouple. is doing. Generally, the sheath in the sheath type thermocouple is made of stainless steel.

[0004]

By the way, for example, in a sheath type thermocouple for the purpose of measuring high temperature, since the sheath is exposed to a high temperature atmosphere, the material of the sheath is an expensive alloy having excellent heat resistance such as Hastelloy. There is a material in which the sheath has a property of withstanding a high temperature atmosphere.

However, when the sheath type thermocouple is installed at the location where the temperature is measured, the portion of the entire length of the sheath that is actually directly exposed to the high temperature atmosphere is the tip of the sheath where the detection end of the thermocouple element is located. In many cases, it is close, and other parts such as the sheath are located inside the member holding the sheath type thermocouple and are not directly exposed to the high temperature atmosphere.

Therefore, it is very uneconomical to form the entire sheath with an expensive material such as Hastelloy so that the distal end of the sheath directly exposed to a high temperature atmosphere has excellent heat resistance.

On the other hand, when the sheath type thermocouple is installed at a place where temperature is measured, the middle part of the sheath is often held by a holding member. In this case, the middle part of the sheath comes into contact with the holding member. It is sometimes desirable to be formed of a metal material having excellent wear resistance and wear resistance.

Therefore, in the former case, the portion of the sheath excluding its tip is made of, for example, stainless steel, only the tip of the sheath is made of a material having excellent heat resistance, and both are joined by welding, for example. It is conceivable that the entire sheath is manufactured.

In the latter case, the portion of the sheath excluding its middle portion is formed of, for example, stainless steel, and only the middle portion of the sheath is formed of a metal material having excellent wear resistance. It is conceivable to join and manufacture the entire sheath.

However, in these cases, it is very difficult to join the distal end portion, the intermediate portion and the other portion of the sheath by welding, and the welded joint portion may deteriorate and the sheath may be broken there. .

Therefore, it is desired to meet the above-mentioned demands on the sheath without impairing the economical efficiency, strength, and original characteristics of the thermocouple. The present invention has been made based on the above circumstances, and an object of the present invention is to provide a sheath-type thermocouple capable of imparting the properties required for a sheath without impairing the economical efficiency, strength, and original properties of the thermocouple. To do.

[0012]

In order to achieve the above-mentioned object, a sheath type thermocouple of the present invention fills an inside of a sheath made of a metal whose tip is sealed with an insulator, and thermoelectrically charges the inside of the insulator. In a sheath type thermocouple having a pair of elements embedded therein, a part of the sheath has a small diameter part having a smaller diameter than the other part, and the small diameter part is made of a metal different from the metal forming the sheath. The body is fitted, the inner surface of the cylindrical body is in close contact with the outer surface of the small diameter portion, and the outer surface of the cylindrical body is flush with the outer surface of the sheath.

[0013]

By fitting a tubular body made of a metal material having a predetermined characteristic on the outer side of the small diameter portion of the sheath, the predetermined portion of the sheath can have a specially required characteristic. In order to provide the sheath with the partially required characteristics, a tubular body made of a metal having the required characteristics is provided in that portion. Therefore, when the entire sheath is made of a metal having the required characteristics. It is very economical compared to.

Further, the portion of the sheath where the tubular body is provided is thick because the thickness of the small diameter portion and the thickness of the tubular body overlap each other, and the mechanical strength is large. Further, the location of the sheath into which the tubular body is fitted is the small diameter portion, and the outer surface of the tubular body is almost the same as the outer surface of the sheath, and the inner surface of the tubular body is in close contact with the outer surface of the small diameter portion. The degree to which the external heat is transferred to the thermocouple element is good, so that the provision of the tubular body does not deteriorate the thermal response characteristics.

[0015]

Embodiments of the present invention will be described with reference to the drawings. An embodiment of the present invention will be described with reference to FIGS. In the sheath thermocouple of this embodiment, a tubular body is fitted to the tip of the sheath so that the tip of the sheath has heat resistance.

The sheath type thermocouple has a sheath 1 made of a metal whose tip is sealed, an insulating powder 2 as an example of an insulator filled in the sheath 1, and an insulating powder 2 embedded in the insulating powder 2. And a thermocouple element 3.

The sheath 1 is entirely made of stainless steel (SUS321) in consideration of corrosion resistance, for example, and the insulating powder 2
For example, magnesia powder is used in consideration of heat resistance and insulation, and the thermocouple element 3 is formed of, for example, alumel-chromel.

Further, the distal end portion of the sheath 1 is formed with a small diameter portion 1a having a diameter d1 smaller than the diameter d0 of other portions. The diameter d1 of the small diameter portion 1a is the sheath 1
The diameter d0 is about 1/2 to 1/3, and the length of the small diameter portion 1a is about 10 to 20 times the diameter d1.

A tubular body 4 is fitted and fixed to the small diameter portion 1a at the tip of the sheath 1. The tubular body 4 is formed on the distal end portion of the sheath 1 with an alloy having excellent heat resistance, for example, Hastelloy X.

The tubular body 4 is a cylindrical body having a closed tip, and is concentrically fitted from the outside of the small diameter portion 1a of the sheath 1. The inner surface of the tubular body 4 is pressure-bonded to the outer surface of the small diameter portion 1a, and the outer surface of the tubular body 4 is flush with the outer surface of the sheath 1.

When manufacturing this sheath type thermocouple,
First, as shown in FIG. 2, the thermocouple element 3 is placed inside the sheath 1.
And the insulating powder 2 are filled. Then, the sheath 1 is swaged, or is not processed, and the distal end portion of the sheath 1 is covered with the tubular body 4.

At this time, the cylindrical body 4 is swaged as will be described later and has a size capable of being reduced to a diameter equal to the diameter of the sheath 1 as shown in FIG. There is.

Further, as shown in FIG. 3, the cylindrical body 4 has a convex portion 4a.
By providing the convex portion 4a, the convex portion 4a is fitted to the sheath 1 after the swaging process, the adhesion between the convex portion 4a and the sheath 1 is improved, and excellent drop-out prevention during use becomes possible.

Next, when the sheath 1 is swaged in advance, the tubular body 4 is swaged so that the tubular body 4 has a diameter of the sheath 1 as shown in FIG.
Reduce the diameter to the same size as d0. Then, the portion of the sheath 1 into which the tubular body 4 is fitted is reduced in diameter to become the small diameter portion 1a, and the tubular body 4 is fixed to the small diameter portion 1a.

If the sheath 1 is not swaged in advance, the tubular body 4 and the sheath 1 are swaged so that the tubular body 4 has the same diameter d0 as that of the sheath 1 as shown in FIG. Reduce the diameter to the size.

The sheath type thermocouple thus constructed is
By fitting the cylindrical body 4 made of a metal material having a predetermined characteristic on the outer side of the small diameter portion 1a of the sheath 1, it is possible to give necessary portions of the sheath 1 with necessary characteristics different from the metal forming the same. it can.

That is, in this embodiment, the distal end of the sheath 1 is fitted with the cylindrical body 4 made of Hastelloy X so that the distal end of the sheath 1 where the detection end of the thermocouple element 3 is located has heat resistance. be able to. Therefore, the sheath 1
It becomes possible to hold the thermocouple by placing the distal end of the sheath in a high temperature atmosphere and measure a high temperature, and it is required for the sheath 1 to have the partially required characteristics. Since the tubular body 4 made of a metal having the characteristic is provided, it is very economical as compared with the case where the entire sheath 1 is made of the metal having the required characteristic.

Further, in the portion of the sheath 1 where the tubular body is provided, the wall thickness of the small diameter portion 1a and the wall thickness of the tubular body 4 overlap each other, and the mechanical strength is large. Further, the location of the sheath 1 into which the tubular body 4 is fitted has a small diameter for blocking at the small diameter portion 1a, and the outer surface of the tubular body 4 is substantially the same as the outer surface of the sheath 1 and the inner surface of the tubular body 4 is the same. Adheres to the outer surface of the small-diameter portion 1a, the degree of external heat reaching the thermocouple element 3 is good, and therefore the thermal response characteristics of the portion where the tubular body 4 is provided in the sheath 1 are not deteriorated.

A specific example will be described. The diameter d0 of the sheath 1 in the thermocouple is 2.3 mm, and the diameter d of the small diameter portion 1a.
1 is 1.6 mm and the length is 15 mm. The outer diameter and the inner diameter of the cylindrical body 4 conform to the dimensions of the sheath 1.

When the exhaust gas temperature of the jet engine is measured using the thermocouple, the thermocouple is fixed to the outer surface of the engine casing 6 of the jet engine by the terminal box 5 as shown in FIG. Is disposed inside a guide vane 7 provided perpendicular to the flow of the hot gas (for example, 1100 ° C.). The guide vane 7 is provided with a gas inlet 8 and a gas outlet 9 so that the high temperature gas hits the cylindrical body 4 made of Hastelloy X at the tip of the sheath 1 of the thermocouple.

In the above structure, the hot gas comes into contact with the tip portion, that is, the heat-sensitive portion in an intensive manner, but since the tubular body 4 made of Hastelloy X having heat resistance is fitted to the tip portion, an excellent effect is obtained. Can be obtained.

Next, another embodiment of the present invention will be described with reference to FIGS. In the thermocouple of this embodiment, a tubular member is fitted to the intermediate portion of the sheath 1 by the holding member 11,
The wear resistance of the intermediate portion of the sheath 1 is improved. That is, the middle part of the thermocouple, for example, the fixing part of the thermocouple to the other base body is made to withstand severe wear due to vibration during use. 1 and 2 in FIGS. 5 and 6.
The same parts as are indicated by the same reference numerals.

5 and 6 show the intermediate portion of the sheath type thermocouple 1. The sheath 1, the insulating powder 2, and the thermocouple element 3 in the thermocouple 1 are made of the same material as that of the above-mentioned embodiment.

A small diameter portion 1b is formed in the middle portion of the sheath 1, and a cylindrical body 10 is fitted in the small diameter portion 1b. The tubular body 10 is made of a metal having excellent wear resistance, for example, stellite, and has a cylindrical body with both ends open.

The sheath 1 thus constructed has a cylindrical body 10
The portion is held by the holding member 11. Since the tubular body 5 has abrasion resistance, the sheath 1 is stably held without being worn.

The sheath 1 is manufactured in the same manner as the above-mentioned embodiment and has the same effect. When the exhaust gas temperature of a jet engine having a configuration different from that of the jet engine described above is measured using the thermocouple, the thermocouple shown in FIG. 7 is provided on the outer surface of the engine casing 6 of the jet engine by the terminal box 5. It is fixed and is positioned so that it is perpendicular to the gas flow.

In this jet engine, the low-temperature gas and the high-temperature gas individually flow, and they are separated by the holding member (inner casing) 11. The thermocouple is held by a holding member (inner casing) 11.

In the above structure, since the thermocouple is held by the holding member (inner casing) 11 at the portion of the cylindrical body 10 made of stellite having abrasion resistance, the sheath is stably held without being worn. It

The present invention is not limited to the above-described embodiment, but can be modified in various ways. The material forming the cylinder is a metal material having the properties required for the sheath.

[0040]

As described above, according to the sheath type thermocouple of the present invention, by fitting the cylindrical body made of the metal material having the predetermined characteristics to the outside of the small diameter portion of the sheath, the predetermined sheath can be obtained. It is possible to give the part special properties. In order to provide the sheath with the partially required characteristics, a tubular body made of a metal having the required characteristics is provided in that portion. Therefore, when the entire sheath is made of a metal having the required characteristics. It is very economical compared to.

Further, the portion of the sheath where the tubular body is provided is thick because the thickness of the small diameter portion and the thickness of the tubular body overlap each other, and the mechanical strength is large. Further, the location of the sheath into which the tubular body is fitted is the small diameter portion, the wire diameter of the element is small, the outer surface of the tubular body is almost the same as the outer surface of the sheath, and the inner surface of the tubular body is outside the small diameter portion. Since it adheres to the surface, the degree of transfer of external heat to the thermocouple element is good,
Therefore, the thermal response characteristic is not deteriorated even if the tubular body is provided. Therefore, according to the present invention, it is possible to provide a sheath-type thermocouple having the properties required for the sheath without deteriorating the economical efficiency, the strength, and the original properties of the thermocouple.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a sheath type thermocouple according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a sheath and a tubular body in an exploded manner in the sheath type thermocouple of the same embodiment.

FIG. 3 is a cross-sectional view showing another cylindrical body used in the sheath type thermocouple of the embodiment.

FIG. 4 is a view showing a case where the sheath type thermocouple of FIG. 1 is used in a jet engine.

FIG. 5 is a sectional view showing a sheath type thermocouple according to another embodiment of the present invention.

FIG. 6 is an exploded cross-sectional view showing a sheath and a tubular body in the sheath-type thermocouple of the same embodiment.

FIG. 7 is a diagram showing a case where the sheath thermocouple of FIG. 5 is used in a jet engine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sheath, 1a, 1b ... Small diameter part, 2 ... Insulating powder, 3 ... Thermocouple element 4, 5 ... Cylindrical body.

Claims (1)

[Claims] 1. A sheath-type thermocouple in which a sheath made of a metal whose tip is closed is filled with an insulator and a thermocouple element is embedded in the insulator, wherein a part of the sheath is The other portion has a small diameter portion with a small diameter, and a cylindrical body made of a metal different from the metal forming the sheath is fitted to the small diameter portion, and the inner surface of the cylindrical body is on the outer surface of the small diameter portion. A sheath-type thermocouple, which is in close contact with the outer surface of the cylindrical body and is flush with the outer surface of the sheath.