JPH02144875A - self temperature control heater - Google Patents

Abstract

PURPOSE:To prevent inflammation and fuming when the temperature of a resistor becomes the melting point of crystalline resin in use by forming a pair of electrodes integrally with a positive resistance temperature characteristic resistor, covering them with an insulating sheath material, fitting a spring on the surface of the insulating sheath material, and fixing the whole with a sheath material. CONSTITUTION:A pair of electrodes 2 and 3 are fitted across a positive resistance temperature characteristic resistor 1, they are covered by an insulating sheath material 4, a spring 5 is fitted to the surface of the insulating sheath material 4 in the shrunk state, and the whole is fixed by a sheath material 6. Since the spring 5 is provided on the surface of the insulating sheath material 4, the shape holding property of crystalline resin is lost when heat is applied to the positive resistance temperature characteristic resistor 1 from another heat source and the temperature of the resistor 1 becomes the melting point or above of crystalline resin in use. The occurrence of an abnormality when the overcurrent flows is easy to detect, this overcurrent is detected by a circuit and the power is cut off, thereby inflammation and fuming can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a self-temperature control heater using a positive resistance temperature coefficient heating element used in heating appliances and general heating appliances.

2. Description of the Related Art It has been well known that a resistor made of a crystalline resin in which conductive particles are dispersed has positive resistance temperature characteristics. Attempts have been made to produce a heating element with self-temperature control by using this in the form of an ink or a flexible composition. The advantages of this method are that the shape of the resistor is excellent and any shape can be easily obtained, and that it has excellent flexibility.
Since the resistance value can be adjusted over a wide range, it has been used as a planar heating element and a long heating element.

Problems to be Solved by the Invention The resistance temperature characteristics of the above resistor are determined by the softening point T of the crystalline resin.
, there is a tendency for the resistance to rise sharply near the melting point T2 and to decrease from the melting point T2 (negative resistance temperature characteristic region). This characteristic is the third
As shown in the figure. Therefore, when used under normal conditions with voltage applied, there is no problem as the temperature is below the softening point of the crystalline resin, but heat is added to the resistor by other heat sources and the temperature of the resistor is used. If the temperature exceeds the melting point of the crystalline resin,
Since it falls into the negative resistance-temperature characteristic region, there was a problem that the temperature would rise abnormally due to its own heat generation and cause a fire.

Furthermore, in this case, even if a fire were to occur, no overcurrent would flow and it would be extremely difficult to detect it.

In addition, to detect abnormal conditions such as ignition, it is possible to use a means to detect temperature using a plastic thermistor, but in any case, including the circuit would be expensive.
This will be a new challenge.

The present invention solves this conventional problem by detecting at a low cost that the temperature has exceeded the melting point of the crystalline resin used in the positive resistance temperature characteristic resistor, and promptly cutting off the supplied power. The purpose of the present invention is to provide a heater with less risk of ignition.

Means for Solving the Problems In order to solve the above problems, the self-temperature control heater of the present invention includes a positive resistance temperature characteristic resistor in which conductive fine particles are dispersed in a crystalline resin, and the positive resistance temperature characteristic resistor. a pair of electrodes formed integrally with the positive resistance temperature characteristic resistor, an insulating sheathing material covering the positive resistance temperature characteristic resistor and the pair of electrodes, an elastic body attached to the surface of the insulating sheathing material, and an elastic body enclosing the entirety of the insulating sheathing material. It is made of exterior material.

Operation The technical operation of the present invention is as follows. Because a spring is provided on the surface of the insulating exterior material, if heat is applied to the resistor by another heat source and the temperature of the resistor exceeds the melting point of the crystalline resin used, the shape retention of the crystalline resin will deteriorate. Because of this loss, the external force applied by the spring causes the electrodes to come into contact with each other, causing an overcurrent to flow and creating a state where it is easy to detect that an abnormality has occurred.

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

In Figure 1, a pair of electrodes 2.3 are installed across a positive resistance temperature characteristic resistor l (distance between electrodes 1 m).
, these are covered with an insulating exterior material 4. A spring 5 was attached in a compressed state to the surface of this insulating sheathing material 4, and the whole was fixed with a sheathing material 6.

Figure 2 shows the data obtained by measuring the distance between the electrodes by varying the ambient temperature of the self-temperature control heater (spring pressure 1 kg/lj), and the distance between the electrodes is reliably reached at melting points of 12 or higher. and make contact. Further, since these self-temperature control heaters are used at a temperature below the softening point T1, there is no problem with the spring pressure during normal use.

Here, the spring pressure was set at 1 kg/-, but it may also work with less than that.

In the above configuration, the positive resistance temperature characteristic resistor is pressurized by a spring via an electrode. Therefore, the positive resistance temperature variable resistor is deformed by the spring pressure at a temperature equal to or higher than the melting point of the crystalline resin that is the constituent material of the positive resistance temperature variable resistor, and both electric rods come into contact with each other. Therefore, if heat is applied to the resistor by another heat source and the temperature of the resistor exceeds the melting point of the crystalline resin used, the shape retention of the crystalline resin will be lost and the external force applied by the spring will decrease. This causes the electrodes to come into contact with each other, causing an overcurrent to flow, making it easy to detect that an abnormality has occurred. By detecting this with a circuit and cutting off the voltage applied to the self-temperature control heater, ignition and smoke generation can be prevented.

Effects of the Invention As described above, according to the self-temperature control heater of the present invention, when heat is applied to the resistor by another heat source and the temperature of the resistor exceeds the melting point of the crystalline resin used, the temperature of the crystalline resin increases. Due to the loss of shape retention, the electrodes come into contact with each other due to the external force applied by the elastic body, causing an overcurrent to flow and making it easy to detect that an abnormality has occurred. The effect is that ignition and smoke can be prevented by detecting the second current in the circuit and cutting off the voltage applied to self-temperature control. Furthermore, since the structure is simple, it can be manufactured at low cost.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a self-temperature control heater according to an embodiment of the present invention, and Fig. 2 shows the ambient temperature and the distance between the electrodes 1...
Positive resistance temperature characteristic resistor, 2, 3... Electrode, 4.
...Insulating exterior material, 5...Spring, 6
...Exterior material. Diagram/--11th Technique Torture Moisture Bamboo Name Resistance Figure Tempering 0] Man: Soften, enemy point.

Claims (1)

[Claims] a positive resistance temperature variable resistor in which conductive fine particles are dispersed in a crystalline resin; a pair of electrodes integrally molded with the positive resistance temperature variable resistor; and a positive resistance temperature variable resistor and the pair of electrodes. A self-temperature control heater comprising an insulating sheathing material, an elastic body attached to the surface of the insulating sheathing material, and a sheathing material surrounding the entirety of these members.