JP2576678Y2 - Heat resistant thermocouple - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a thermocouple used for measuring a high temperature.

(Prior Art) As a conventional technique according to the present invention, there is a thermocouple shown in FIG.

In FIG. 2, reference numeral 1 denotes a sheath for protecting an internal thermocouple wire, and 2 denotes a lead wire in which a metal wire is wired. The end of the thermocouple wire protruding from the sheath 1 and the end of the lead wire 2 are connected and fixed by a crimp sleeve 3.
The sheath 1 is fixed by caulking at the adapter 4 and the portion indicated by reference numeral 6. Then, the epoxy resin 5 is filled in the adapter 4, dried by heating, and the sheath 1 and the lead wire 2 are fixed.

(Problems to be solved by the invention) However, the thermocouple as described above can be used only in a place where the temperature is 100 to 120 ° C or lower, and the sheath 1 is set so that the ambient temperature near the adapter 4 becomes 100 ° C or lower. It was stretched and used.

This is because the epoxy resin is used in the adapter 4, and when the temperature is applied to the adapter 4, the epoxy resin inside expands and separates, and the thermocouple protrudes from the sheath 1 by separating the crimping sleeve 3. This is because the connection between the end of the wire and the end of the lead wire 2 is separated and disconnected.

It is a technical object of the present invention to provide a thermocouple structure that can be used sufficiently even when the temperature near the adapter reaches a high temperature such as 150 ° C. or more in a lead wire type thermocouple.

[Structure of device]

(Means for Solving the Problems) The first technical means taken in the present invention to solve the above technical problems is as follows. That is, a thermocouple wire for measuring a high-temperature portion, a sheath for protecting the thermocouple wire, a lead wire for measuring current, and a hollow inside and one end fixed to the sheath by caulking. And the other end is screwed to the sleeve,
An end of the thermocouple wire and an end of the lead wire are connected and held by a welding member, and a joint joined by the welding member is accommodated in a hollow space of the adapter, and the sleeve is A heat-resistant thermocouple is formed by caulking and fixing the lead wire.

Further, in solving the above technical problem, the second technical means taken in the present invention is to make the sleeve in the first technical means be brass.

(Operation) According to the first technical means, the connection between the end of the thermocouple wire and the end of the lead wire, which is connected and held by the welding member, is accommodated in the hollow space of the adapter. I have.
For this reason, even if the inside of the adapter becomes a high temperature atmosphere, there is no resin that expands and melts around the connection portion. Therefore, the junction or the lead wire is not cut or broken, and the thermocouple can withstand high temperatures.

Further, according to the second technical means, since the brass sleeve which is a relatively soft metal is used as the sleeve, the brass sleeve bites into the lead wire when it is fixed by caulking to the lead wire, and is securely fixed. . For this reason, even when external force such as pulling the lead wire is applied, the lead wire is securely fixed to the brass sleeve,
This does not move or shift, and tensile stress is applied to the sheath and the lead wire, and they are not cut or broken.

(Example) Hereinafter, an example is described.

FIG. 1 is a cross-sectional view of a thermocouple according to the present embodiment. In the figure, reference numeral 1 denotes a sheath made of alumina or the like. The sheath 1 protects a high-temperature portion measurement wire 2a as a thermocouple element made of a nickel-chromium alloy, which is a temperature measuring element. Is a state in which the high-temperature portion measurement line 2a is projected. Reference numeral 2 denotes a lead wire. The metal wire 2a is wired inside the lead wire 2, and as shown in the figure, the illustrated end of the lead wire 2 is in a state where the metal wire 2a protrudes. Note that an end (not shown) of the lead wire 2 is connected to a measuring instrument. The illustrated end of the high-temperature portion measurement line 1a is connected to and held by silver-brow welding with the end of the protruding metal wire 2a constituting the illustrated end of the lead wire 2.

Reference numeral 11 denotes a stainless steel hollow adapter. The adapter 11 includes a high-temperature portion measurement line 1a protruding from the illustrated end of the sheath 1, a protruding portion of the metal element wire 2a forming the illustrated end of the lead wire 2, and a high-temperature portion measurement line subjected to silver-low welding. The joint 13 between the metal wire 1a and the metal strand 2a is arranged so as to be accommodated in a hollow portion inside thereof.
Is fixed to the sheath 1 by crimping into a hexagonal shape and performing silver-low welding. Further, a female screw portion is formed on the inner periphery of the other end on the right side of the adapter 11 in the drawing.

12 is a brass sleeve. The brass sleeve 12 has a male screw portion formed on the outer periphery thereof, and the adapter 11 and the brass sleeve 12 are fixed by screwing the male screw portion and the female screw portion formed on the adapter 11. In this case, the two members can be firmly fixed by screwing them together with the ceramic adhesive for heat resistance applied. The right end 12a of the brass sleeve 12 in the figure is crimped to the lead wire 2 in a hexagonal shape. Thus, the lead wire 2 is fixed to the adapter 11 via the brass sleeve 12.

In the thermocouple having the above-described configuration, even when the vicinity of the adapter 11 becomes an atmosphere of 150 ° C. or more during high-temperature measurement, a thermal expansion material such as an epoxy resin is not in the adapter as in the related art, and is hollow. As is clear from the comparison between FIG. 1 and FIG. 2, since the silver brazing portion between the thermocouple wire 1a and the metal wire 2a of the lead wire 2 is formed relatively short, bending and elongation due to thermal expansion are reduced. It does not act on the thermocouple wire 1a and the metal wire 2a. Therefore, thermocouple wire 1a, metal wire 2a,
Disconnection and breakage of the joint 13 do not occur, and measurement in a high temperature state becomes possible.

(Effects of the Invention) The present invention has the following effects.

(1) It can be used satisfactorily even when the temperature around the adapter is around 500 ° C.

(2) Since the temperature around the adapter is measured at about 100 ° C. as in the conventional case, the length of the sheath does not need to be increased, and the cost can be reduced.

(3) When a brass sleeve is used as the sleeve,
When caulking to the lead wire, the brass sleeve bites into the lead wire and is fixed securely. Therefore, even when an external force such as a lead wire is applied,
The lead wire is securely fixed to the brass sleeve, which does not move or slip and apply tensile stress to the sheath and the lead wire, which does not cut or break.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a heat-resistant thermocouple in this embodiment, and FIG.
The figure is a cross-sectional view of a conventional thermocouple. 1 ... sheath, 1a ... high-temperature part measurement wire (thermocouple element wire), 2
…… Lead wire, 2a …… Metal wire, 11 …… Adapter, 12
…… Brass sleeve, 13 …… Junction, 12a, 14 …… Crimping

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-60-73424 (JP, A) JP-A-58-134745 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01K 7/02

Claims (2)

(57) [Scope of request for utility model registration] 1. A thermocouple wire for measuring a high-temperature portion, a sheath for protecting the thermocouple wire, a lead wire for measuring a current, a hollow inside and one end having the sheath. And an adapter whose other end is screwed to the sleeve. The end of the thermocouple wire and the end of the lead wire are connected and held by a welding member, and joined by the welding member. A heat-resistant thermocouple in which a joint is accommodated in a hollow space of the adapter and the sleeve and the lead wire are fixed by caulking. 2. The thermocouple for heat resistance according to claim 1, wherein said sleeve is made of brass.