JPS63143783A - Temperature self-control type dielectric heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heater, and more particularly to a dielectric heater equipped with a self-temperature control mechanism.

(Prior Art) In general, a heater is a heating element that utilizes Joule heat by passing an electric current, as is known from the past with a nichrome wire or the like. In addition to this, there are many other devices that utilize infrared or far-infrared radiation.

(Problem to be solved by the invention) By the way, in order to obtain the desired temperature, the above-mentioned heater generally requires, in addition to the heating element, a control device that detects the temperature and controls the heating element. be. In other words, in order to perform the heater function, there are two things: the heating element and the control device.
A set of equipment is absolutely necessary.

The present invention has been made in view of these points, and an object of the present invention is to provide a heater in which the heating element itself has a self-temperature 'tJ control function.

(Means and effects for solving the problem) In this invention, a dielectric having a dielectric loss peak at a specific temperature is used as a heating element, and the temperature characteristic of this dielectric loss (tan δ) is used to increase the temperature of the heating element itself. It has a control function.

(Example) The principle of the self-temperature-controlled dielectric heater of the present invention will be explained below, prior to examples.

A dielectric has a dielectric loss (tan δ), and if this dielectric loss is large, the dielectric generates heat and can be used as a heater. JAN15(a) of the dielectric material shows temperature dependence, and if it shows a sharp peak at a certain temperature, then by applying an AC voltage to the dielectric material, the dielectric material will continue to generate heat at a certain temperature. Beyond jan
Since the δ value drastically decreases, the amount of heat generated decreases, and the temperature of the dielectric decreases due to heat dissipation, and when it reaches a certain temperature, the jan δ value increases again, and the dielectric starts generating heat again. In other words, the temperature of a dielectric is the tan of that dielectric.
Due to the δ-temperature characteristics, it is possible to always maintain a constant temperature. By utilizing this principle and using a dielectric as a heating element of a heater, it is possible to create a self-temperature-controlled heater.

In this invention, polyethylene is used as the FJ'llt body. For example, if 2,5-dimethyl-3-hexyne-2,5 diol is present in polyethylene, La
The relationship between the nδ value and temperature is shown in Figure 2.
It shows a sharp peak value in tan δ near 0°C. Therefore, when an AC voltage is applied to polyethylene containing 2,5-dimethyl-3-hexyne-2,5 diol, the temperature rises due to heat generation due to dielectric loss. However, when the temperature reaches 80° C. or higher, the jan δ value decreases slightly and the heat generation stops. on the other hand.

When the temperature of polyethylene drops below 80'C due to heat dissipation, the tan δ value rises again and heat generation begins. In other words, the temperature of the polyethylene itself can be kept constant at about 80° C. due to the relationship between tan δ and temperature characteristics.

By the way, the relationship between the concentration of 2,5-dimethyl-3-hexyne-2,5 diol and tan δ is as shown in Figure 3, and in order to increase tan δ, 2,5-dimethyl-3-hexyne -2,5 diol concentration or 0.15
Wt% or more is required.Furthermore, in order to have an effective janδ value for heat generation,
A concentration of about 0.2 wt$ is desirable.

Furthermore, the electric field dependence of tan δ is shown in FIG. This figure shows that the concentration of 2,5-dimethyl-3-hexyne-2,5 diol is 0. :The state of a 1wt1 sample at a temperature of 60°C! This is the case with a spoon. As can be seen from this figure, tan δ increases as the electric field increases, so it is desirable to apply a high electric field to make it act as an effective heating element. Therefore, in order to actually obtain a high electric field, the thickness of the polyethylene film must be made as thin as possible.

At a commercial voltage of 100V, it is possible to make the film act as a heater with a film thickness of about lopm.

Next, an embodiment of the self-temperature-controlled dielectric heater of the present invention will be described based on FIG.

Electrodes 2.2 are provided on both sides of a polyethylene film l containing 2,5-dimethyl-3-hexyne-2,5 diol by vapor deposition or the like. The upper and lower surfaces are covered with a glass volatilization prevention layer 3 together with spacers 5.5 on both sides in a sealed manner so that the 2,5-dimethyl-3-hexyne-2,5 diol contained in the polyethylene film l does not volatilize. . This volatilization prevention layer 3 may be made of a polymeric material with good airtightness if flexibility is required for the heater. The outside is surrounded by a heat dissipation layer 4 having an appropriate thermal conductivity.

Thus, by applying a high voltage to the electrode 2.2, the dielectric film l is raised to a temperature of 80°C. When the temperature exceeds 80°C, the jan δ value of the dielectric film l suddenly decreases and heat generation stops, and the heat is dissipated from the heat dissipation layer 4, etc., and the temperature decreases, and the dielectric film l is heated again.
generates heat, and the heater is kept at a constant temperature of about 80°C.

In order to obtain a desired temperature of the heater below 80'C, this can be achieved by changing the heat dissipation layer 4 on the top of the heater to a material having an appropriate value of thermal conductivity.

In the above example, a polyethylene dielectric film containing 2,5-dimethyl-3-hexyne-2,5 diol was explained as a heating element, and polyethylene generally has a melting point around 110°C to 130°C. Therefore,
When polyethylene is exposed to high temperatures, it may soften at temperatures near SO'C, making it difficult to use. One way to improve this is to crosslink polyethylene to improve its thermal properties. In order to crosslink polyethylene, a chemical crosslinking agent is often used, and the crosslinking agent is 2,5-dimethyl-2,5-(
When tertiary stilburoxy)-hexyne-3 is used, 2,5-dimethyl-3-hexyne-2,5 diol is produced simultaneously with the crosslinking of bosoethylene by the decomposition reaction of the crosslinking agent. In this way, it is possible to make a heater using crosslinked polyethylene, which has good thermal properties, as a material.

(Effects of the Invention) As described above, according to the present invention, since the heater heating element itself has a temperature control function, it has the function of maintaining a constant temperature by applying voltage to the heating element, and It is possible to easily manufacture a heater that does not require any temperature control device such as an attached one.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the self-temperature-controlled dielectric heater of the present invention. FIG. 2 is an example of temperature characteristics showing the relationship between dielectric loss and temperature of the dielectric film of the present invention. The characteristic diagram, FIG. 3, shows the dielectric loss of the dielectric film of the present invention and 2.5
- Dimethyl-3-hexyne-2,5 diol A characteristic diagram showing the concentration dependence showing the relationship between the concentrations; FIG. 4 shows the electric field dependence showing the relationship between the dielectric loss and electric field of the dielectric film of the present invention. It is a characteristic diagram which is an example.

Claims (1)

[Claims] A self-temperature-controlled dielectric heater characterized in that a dielectric having a dielectric loss peak at a specific temperature is used as a heating element.