JPS6324416Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cable-like temperature detection sensor that captures and detects changes in electrical resistance between conductors in response to temperature changes.

Generally, temperature detection sensors detect points using temperature-sensitive elements such as thermocouples and thermistors, and therefore have the disadvantage that an extremely large number of sensors must be used when temperature detection over a wide range is required.

Therefore, the object of this invention is to provide a temperature detection sensor that can detect temperature over a wide range using one or a very small number of temperature detection sensors. Therefore, according to this invention, a temperature detection sensor is formed that includes at least two conductors spaced apart and an unfired or incompletely fired conductive tetrafluoroethylene resin body that is in conductive contact with each of the conductors. The temperature is detected based on the change in resistance of the conductive tetrafluoroethylene resin body, which expands and contracts in response to temperature changes. By forming it in this way, it can be made into a cable-like temperature detection sensor, and by winding the temperature detection sensor, it is possible to detect a wide range of temperature, and the temperature change point can be detected depending on the cable length leading to the temperature change point. can be detected as Therefore, especially if the conductor is a high-resistance conductor such as a stainless steel wire, the distance from the starting end of the cable-shaped temperature detection sensor to the temperature change point can be detected as a resistance value proportional to the distance. In addition, since conductive tetrafluoroethylene resin is used as the conductive resin body, it has excellent chemical and physical properties and can provide a stable temperature detection sensor. If ethylene resin is used, it is advantageous that a large change in electrical resistance value can be obtained because the electrical non-contact or contact between the conductive substances changes greatly as the resin body expands or contracts in response to temperature changes.

Next, this invention will be explained in more detail with reference to the drawings.

In FIG. 1, the temperature at which the conductive tetrafluoroethylene resin body 2, which is in electrical conductive contact with each of the two conductors 1, is held between two resin protective films 3 and takes on the shape of a flat cable is shown. A detection sensor 4 is shown. In this case, it is convenient to use a high-resistance conductor such as a stainless steel wire as the conductor 1 because the point of temperature change can be easily detected as the resistance value of the temperature detection sensor. In addition, if the conductive tetrafluoroethylene resin body 2 is an unfired or incompletely fired stretched porous conductive tetrafluoroethylene resin body, the resistance value of the temperature detection sensor will change significantly in response to temperature changes. It is convenient because it appears. In order to impart conductivity to the tetrafluoroethylene resin, carbon black, carbon fiber chips, metal powder, metal compound powder, etc. are mixed into the tetrafluoroethylene dispersion and then coagulation is performed. It is preferable to obtain it by mechanically mixing it with ethylene tetrafluoride powder. Further, the stretched porous conductive tetrafluoroethylene resin body is manufactured, for example, by the method described in Japanese Patent Publication No. 51-18991. Briefly, a mixture of conductive tetrafluoroethylene resin powder (conductive PTFE powder) and liquid lubricant (e.g., solvent naphtha, petroleum, etc.) is prepared by pasting, extruding, and/or rolling. A sheet-like conductive PTFE molded body having a crystallinity of 100% or higher is formed, and the liquid lubricant is removed from the molded body by volatilization at a temperature of about 100 to 300°C, and then heated to about 327°C.
It stretches in one or more directions at a temperature below (the melting point of PTFE) at a stretching rate of more than 10%/second per unit time.

Flat cable-shaped temperature detection sensor 4 shown in Fig. 1
When the temperature detection sensor 4 was partially immersed in liquefied nitrogen, the temperature detection sensor 4 was rapidly cooled, and as a result, the conductive tetrafluoroethylene resin body 2 contracted and the electrical resistance value suddenly decreased, as shown in Figure 2. It exhibited the characteristics shown below.
Thereafter, when this temperature detection sensor 4 was taken out of the liquid nitrogen and left in the air, it returned to its original resistance value in about 300 seconds. That is, it was confirmed that repeated use was possible.

Note that the electrical resistance value of conductive tetrafluoroethylene resin is infinite at room temperature, and temperature detection accuracy will improve if the conductivity is adjusted in advance so that it shows a finite value at the required measurement temperature. .
In addition, if unfired or incompletely fired tetrafluoroethylene resin is used as a conductive tetrafluoride ethylene resin, instability due to contact resistance can be eliminated by firing only the area around the conductor using Joule heat, etc. can.

FIG. 3 shows another embodiment of this invention. In this case, an outer cover 5 that does not impregnate liquid is provided on the outer periphery of the protective film 3 to prevent malfunctions due to liquid intrusion, etc. ing.

FIG. 4 shows a further different embodiment of this invention, in which an unfired or incompletely fired conductive tetrafluoroethylene resin body 8 is provided between the center conductor 6 and the outer conductor 7 which are spaced apart, and the outermost periphery is It is provided with a tube-shaped jacket 9 that contracts as the temperature decreases.

As described above, this invention provides a temperature detection sensor comprising at least two conductors spaced apart and an unfired or incompletely fired conductive tetrafluoroethylene resin body that is in conductive contact with each of the conductors. By forming this structure, not only can temperature changes be sensitively detected as changes in resistance value due to expansion and contraction of an unfired or incompletely fired conductive tetrafluoroethylene resin body, but also the temperature Since the detection sensor has a cable shape, it is possible to detect temperature over a wide range with one set or a small number of temperature detection sensors.Furthermore, this characteristic can be used not only to detect temperature but also to detect temperature detection such as liquefied nitrogen, liquefied hydrogen, and other vaporized liquids. Detection of the leakage of a liquid having a temperature different from normal temperature and the detection of the leakage point can also be used as a detection of temperature change, which has great industrial benefits. It should be noted that this invention is not limited to the above-mentioned embodiments, and it goes without saying that various changes can be made within the scope of this invention.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the flat cable-shaped temperature detection sensor according to this invention, Figure 2 is a characteristic diagram of the sensor shown in Figure 1, and Figure 3 is a partial cross-section of the flat cable-shaped temperature detection sensor according to this invention. 4 are cross-sectional views of a coaxial cable-like temperature detection sensor according to this invention. 1: Conductor, 2: Conductive tetrafluoroethylene resin body,
3: Protective film, 4: Temperature detection sensor, 5: Outer cover,
6: center conductor, 7: outer conductor, 8: conductive tetrafluoroethylene resin body, 9: tube-shaped outer jacket.

Claims (1)

[Claims for Utility Model Registration] (1) Temperature detection comprising at least two conductors spaced apart and an unfired or incompletely fired conductive tetrafluoroethylene resin body in conductive contact with each conductor. sensor. (2) Utility Model Registration The temperature detection sensor according to claim 1, wherein the conductor is a high resistance conductor. (3) In the temperature detection sensor according to any one of claims 1 and 2 of the utility model registration claims,
A temperature detection sensor characterized in that the conductive tetrafluoroethylene resin body is a stretched porous conductive tetrafluoroethylene resin body. (4) Scope of Utility Model Registration Claims In the temperature detection sensor according to any one of claims 1 to 3, the conductor and the conductive tetrafluoroethylene resin body are surrounded by a common jacket impermeable to liquid. A temperature detection sensor characterized by: (5) Scope of Utility Model Registration The temperature detection sensor according to any one of claims 1 to 4, characterized in that only the conductive tetrafluoroethylene resin body in the vicinity of the conductor is completely fired. Detection sensor.