JPH0572049A - Temperature detecting sensor - Google Patents

Abstract

PURPOSE:To obtain excellent electric insulation all the time even if the temperature of the surrounding part becomes abnormally high by providing spacers of inorganic material such as ceramics at the connecting part of a thermocouple and the connecting part of each element wire of a compensating conductor. CONSTITUTION:A stainless steel flange 3 is coupled with a stainless steel protecting pipe 1, welded and fixed. Spacers 10 and 11 made of inorganic material, such as ceramics are provided for element wires 2 of a thermocouple. Spacers 12 and 13 are provided for element wires 5 of a compensating conductor. Thereafter, the element wires 2 are inserted into the spacer 12, and the element wires 5 are inserted into the spacer 11, respectively. The element wires 2 and the element wires 5 are connected with silver solder between the spacer 11 and the spacer 12. After the connection, the stainless steel protecting pipe 6 is made to pass, the protecting pipe 6 is compressed into the flange 3 and the flange 3 and the protecting pipe 6 are welded and fixed. After the welding, a sensor attaching and fixing bolt 4 is provided. The end part of the protecting pipe 6, which is not welded, is mechanically tightened. When the spacers of the inorganic material are provided, excellent electric insulation is always obtained even if the temperature of the surrounding part becomes abnormally high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is an effective means for a sensor for detecting a temperature of 500 ° C to 1200 ° C.

[0002]

2. Description of the Related Art In the prior art, a glass fiber braided tube impregnated with an organic material such as silicone is used to cover the periphery of each (+) side and (-) side of a thermocouple element wire and a compensation lead wire. It is electrically isolated. With this method, good electrical insulation cannot be obtained, and short-circuit may occur. The reason is that when the temperature around the detecting portion exceeds the alarm temperature and reaches 1200 ° C. in the worst case, the temperature around each connecting portion reaches around 450 ° C. and exceeds the maximum guaranteed temperature of the insulating material.

As a known example related to the conventional technique, there is JP-A-52-122874.

[0004]

[Problems to be Solved by the Invention] The circumference of each connection part on the (+) side and (-) side of a thermocouple wire and a compensating lead wire is covered with a glass fiber braided sleeve impregnated with an organic material such as silicone. Insulated. In this method, if the temperature around the detector reaches 1200 ° C, the ambient temperature of each connection is 5
The temperature reaches around 00 ° C. and exceeds the maximum guaranteed temperature (about 250 ° C.) of the insulating material, so that the insulating material is hardened and loses its shape by impact force and becomes powdery. For this reason, there is a possibility that the respective connection parts will come into contact with each other, and the surrounding protective tube and the respective connection parts will come into contact with each other to cause a short circuit.

[0005]

[Means for Solving the Problems] Several cylindrical or spherical spacers having two holes made of inorganic material such as ceramic and glass beads are inserted into the wires of a thermocouple. Also, several spacers are inserted into the strand of the compensating conductor. After insertion, the thermocouple wire and the compensating lead wire are connected.

[0006]

The inorganic spacers such as ceramics and glass beads have a melting point of 500 ° C. or higher, so that when the temperature around the connecting portion reaches 450 ° C., no change in physical properties occurs, and good electrical insulation can be obtained.

[0007]

EXAMPLE As shown in FIG. 1, a stainless steel flange 3 was inserted into a stainless steel protective tube 1 and welded and fixed. Inorganic spacers 10 and 11 such as ceramics to the thermocouple wire 2
Insert. Similarly, the spacers 13 and 12 are inserted into the strand 5 of the compensating conductor. After that, the thermocouple wire 2 is inserted into the spacer 12, and the compensating lead wire 5 is inserted into the spacer 11.
Then, between the spacer 11 and the spacer 12, the element wire 2 of the thermocouple and the element wire 5 of the compensation lead wire are connected by silver brazing. After the connection, the stainless protective tube 6 is passed through, the stainless protective tube 6 is press-fitted into the stainless flange 3, and the flange 3 and the protective tube 6 are welded and fixed. After welding, the sensor mounting and fixing bolt 4 is passed through, and the unwelded end of the protective tube 6 is mechanically tightened.

[0008]

According to the present invention, as shown in FIG. 1, by providing an inorganic spacer such as ceramics, good electrical insulation can always be obtained even if the surrounding temperature becomes abnormally high.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Stainless protective tube, 2 ... Thermocouple element wire, 3 ... Stainless flange, 4 ... Mounting and fixing bolts, 5 ... Compensating lead wire core wire, 6 ... Stainless protective tube, 7 ... Stainless strip plate, 8 ... A tube formed of an organic material such as silicone, 9 ... An insulating material formed of an organic material such as silicone,
10, 11, 12, 13 ... Spacers formed of an inorganic material such as ceramics.

Claims (1)

[Claims] 1. A temperature detecting sensor, characterized in that an inorganic spacer such as ceramic is provided at a connecting portion between a wire of a thermocouple of a sheath type thermocouple system and a compensating lead wire.