JPS59105531A - Electric cable for sensing temperature - Google Patents

Abstract

PURPOSE:To improve the sensitivity to an abnormal temperature, by arranging an electric cable for sensing temperature arbitrarily at any of desired positions in a room. CONSTITUTION:An electric cable for sensing temperature is prepared in such a manner that a temperature-sensitive substance 4 of negative resistance ceramic is formed continuously in the longitudinal direction on a part of an insulating layer 2 located between electrode layers 3 and 3' and the whole of these elements is covered with an insulating substance 5. When a part of the cable for sensing temperature senses the abnormality of a rising temperature, the resistance between the electrode terminals 3 and 3' reduces sharply, and thereby an alarming device 7 for informating an abnormal temperature, which comprises a relay and a buzzer, etc., is driven by a power source element to inform the abnormality. Since the temperature sensing element of the electric cable for sensing temperature is arranged continously and a temperature sensitive resistance per unit length between the electrode layers 3 and 3' can be maintained precisly in a stable manner, the temperature sensitivity characteristics of the cable can be made uniform, and thus the cable can be made to have little non- uniformity and high reliability.

Description

[Detailed Description of the Invention] A. Field of Industrial Application This invention relates to electric wires for detecting temperature abnormalities caused by fire or other electrical appliances, especially temperature abnormalities in a part of a wide area. be.

BACKGROUND OF THE INVENTION Conventionally, spot-type temperature sensor-based alarm systems have been used to detect fires, for example, in which temperature sensors using bimetal or the like are installed in one or several locations in a room. - In order to increase the density of force sensing, a temperature-sensitive electric wire that senses temperature in a linear manner instead of a spot type has been developed that utilizes the change in characteristics due to melting of materials.

8. Problems to be Solved by the Invention" 2. Conventional spot-type sensors can detect an abnormal rise in temperature in the vicinity of the installed sensor in a relatively short period of time; In the case of individual sensors, the disadvantage is that the response to temperature abnormalities in the middle of each sensor is slow and the sensitivity for disaster prevention is low. Furthermore, temperature-sensitive electric wires that utilize the melting of substances have a large heat capacity and therefore inherently have poor sensitivity.Furthermore, once they are activated, the material structure changes due to re-assimilation and they do not exhibit constant temperature-sensing characteristics.

20 Means for Solving the Problems This invention provides an insulating layer on the surface of a long metal wire, creates two long electrode layers independent of each other on the insulating layer, and further provides a gap between the electrode layers. This is a temperature-sensing wire that is coated with ceramic that has negative resistance characteristics and is insulated throughout the wire. By using ceramic that has negative resistance, the temperature-sensing characteristics of each part of the wire are uniform and have high reliability with little variation. This eliminates the above drawbacks.

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

FIG. 1 is a sectional view showing an embodiment of a temperature sensing electric wire according to an embodiment of the present invention. A long composite body is prepared by forming an insulating layer 2 on the surface of a long metal body 1. The metal body is for maintaining the strength of the wire. Two mutually independent parallel long electrode layers 3.3' are formed on the surface of the insulating layer 2. Next, on the insulating layer 2 between the electrode layers 3 and 3', a temperature sensing element 4 made of negative resistance ceramics having the characteristic that the resistance value sharply decreases at a specific temperature is continuously formed in the longitudinal direction, and further The entire structure is covered with an insulator 5 such as vinyl chloride.

In this case, CVD (Chemical Vapor Depo
Si t ion) method, PVD (PhysicalVap) such as sputtering and ion blating
Our Deposition method, printing and baking method, etc. can be used. Negative resistance ceramic temperature sensor 4
Coefficient) thermistors can also be used, but vanadium oxide V02, V2O3, V2O
5 as the main component, mixed with impurities to adjust the transition point, and has a resistance of 100,000 to 1.5% at room temperature. ．． 00
For example, a high electrical resistance of 0,000 Ω has a resistance of 1 at 60°C.
So-called sudden change resistance thermistor CT that drastically decreases to ~10Ω
R is suitable for use.

Before covering the thermosensitive element 4 with an insulator 5 such as vinyl chloride, the outer layer of the insulator is subjected to moisture-proofing treatment such as face coating.
It is possible to improve moisture resistance.

This temperature sensing wire is wired indoors or the like to form a circuit as shown in FIG. That is, the electrode terminal 3 of the temperature sensing wire
．． 3', a power supply unit 6 and an alarm device 7 such as a relay or a buzzer are connected in series. When a part of the temperature sensing wire detects an abnormal temperature rise, the electrode terminal 3.3' of the temperature sensing wire
Since the resistance between them is drastically reduced, an alarm device 7 such as a relay or a buzzer for notifying a temperature abnormality is driven by the power supply unit 6 to notify the abnormality.

Due to the structure of this temperature sensing wire, the temperature sensing parts are arranged continuously, and the temperature sensing resistance value per unit length between the electrode layers 3, 3' can be maintained stably with high accuracy. Characteristics can be made uniform and high reliability can be achieved with little variation. Furthermore, the cross-sectional shape of the metal body 1 can be sufficiently reduced in both thickness and width, making it suitable for weight reduction.

In the above description, the metal body has a band-shaped cross section, but the cross section may be U-shaped or other irregularly shaped cross section, or may be circular. Further, in the embodiment, an example was shown in which the temperature sensitive bodies were continuously formed between the electrodes, but they may also be arranged evenly between the electrodes with appropriate intervals, thereby reducing the amount of acid used for the temperature sensitive bodies. You can also do it.

1. Effects of the Invention As explained in detail above, the temperature sensing electric wire of the present invention is a long thin electric wire, so it can be placed precisely and freely at a desired position indoors, so it can increase the sensitivity of temperature abnormality detection over a wide area. It is something.

That is, the temperature sensing electric wire of the present invention has excellent characteristics for wide-area temperature monitoring such as indoor use against fires, etc., and is of great value.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of an embodiment of the temperature sensing electric wire of the present invention, and FIG. 2 is a circuit diagram showing an example of a circuit configuration when the same electric wire is used. 1: Metal body, 2: Insulating layer, 3.3': Electrode layer, 4: Temperature sensitive body, 5: Insulator, 6: Power supply section, 7: Relay or alarm device. Agent 1) Osamu Naka 165-, Figure 1, Seki 2

Claims (3)

[Claims] (1) Two parallel, independent long electrode layers are created on the insulating layer of a long composite body with an insulating layer on the surface of a long metal body, and a specific electrode layer is formed on the insulating layer between the electrode layers. A temperature sensing wire characterized by being coated with negative resistance ceramic whose resistance decreases with temperature, and further covered with an insulator. (2) The temperature sensing electric wire according to claim 1, wherein the metal body has a rectangular cross section. (3) A temperature sensing electric wire according to claim 1 or 2, characterized in that a rapid change resistance thermistor CTR whose main component is vanadium oxide is used as the negative resistance ceramic.