JPH044395Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is applicable to airframes such as nitrogen gas and petroleum gas, solids such as ceramics and metals, liquids such as water and oil, or mixtures and powders thereof. , relates to an electric heating device used for heating various materials such as powder and granular materials.

[Prior Art] Conventionally, in electric heating devices, an electric heater made of a ceramic bobbin wrapped with nichrome wire (hereinafter referred to as a bobbin heater) has been used as a heating element for high-temperature heating in electric furnaces, dryers, etc. For applications such as irons that require relatively low heating temperatures, a plate-shaped heater surrounded by mica, plastics, rubber, etc. is used as a heating element.

In addition, with heating elements such as the bobbin heaters and plate heaters mentioned above, it is not possible to provide sufficient electrical insulation between the heating wires such as nichrome wires and the electrically heated object, so recently the heating wires have been replaced with magnesia wires etc. So-called rod-shaped cartridge heaters, which are surrounded by an insulating material and enclosed in a cylindrical metal sleeve, are being used in some cases. Examples include electric heating devices and immersion heaters used in molds for hot molding.

[Problems to be Solved by the Invention] However, conventional bobbin heaters, plate-shaped heaters, rod-shaped cartridge heaters, etc. (hereinafter referred to as heaters) have the following difficulties in use.

First, the heater lacks flexibility in changing its shape and processing. For this reason, when arranging the heater inside the heating container or the housing, the shape of the heater is restricted by the shape of the bobbin, sleeve, etc., and the locations for fixing and mounting the heater are limited. As a result, the heat source becomes localized inside the heating container or the like, resulting in non-uniform temperature distribution inside the container or the housing. Therefore, it becomes difficult to uniformly heat and raise the temperature of the object to be heated. In other words, the object to be heated is heated non-uniformly with a temperature distribution, making it impossible to perform a homogeneous heat treatment.

The second problem is that the watt density of the heater cannot be increased. The outer covering that forms the heater (for example, mica or rubber, which is the outer covering of a plate heater, or
A metal case that serves as a protective outer covering for these or a metal sleeve of a rod-shaped cartridge heater),
Generally, there is a large thermal resistance between the wire and the heating wire that is the heat source. Therefore, there is a large temperature difference between the temperature of the surface of the jacket and the temperature of the heating wire itself. As a result, when an attempt is made to heat the object to a high temperature, the temperature of the heating wire itself constituting the heater increases excessively, and the heating wire deteriorates early. That is, the amount of power that can be injected into the heater (so-called watt density) cannot be increased.

Furthermore, the insulating material surrounding the heating wire has an extremely poor thermal conductivity than the metal material. Furthermore, as mentioned in the first problem, the heater is locally arranged inside the electric heating device. As a result, in order to sufficiently heat the object to be heated, high electric power must be injected into the heater that constitutes one unit, and for this purpose, sufficient electrical insulation between the outer jacket of the heater and the heating wire is required. It is something that must be taken. Therefore, the thickness of the insulating material layer filled between the outer sheath and the heating wire increases, and the thermal resistance further increases, resulting in a vicious cycle of the above problem.

The third problem is that the electric heating device becomes large. As mentioned above, the heaters are arranged locally and distributed within the electrical heating device. Therefore, in order to obtain a uniform heating area over a wide range inside an electric heating device, it is necessary to separate the heater and the object to be heated, or to install a uniform heating plate or the like between the heater and the object to be heated. There must be. As a result, the electric heating device, which is originally small in size, becomes large in size, resulting in a problem in that the overall thermal efficiency of the electric heating device is deteriorated.

It is an object of the present invention to solve the problems of the above-mentioned prior art and to provide a compact and highly efficient electric heating device that can evenly heat an object to be heated.

[Means for Solving the Problems and Their Effects] In order to achieve the above object, the electric heating device of the present invention includes an electric heating wire, a support body supporting the electric heating wire having small mesh-like holes on the outer circumferential surface, and the above-mentioned. The structure includes an electric heater wire and a sprayed film member attached to the support body, and preferably the support body is formed of a net material. Further, the support body may be configured to be removed after the thermal spraying member is applied.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to FIG.

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

The electric heater wire 1 includes a heating wire 2 as a core wire,
This is a so-called sheathed heater wire whose periphery is coated with an insulator 3 and covered with a metal sheath 4.

A nichrome wire is used as the heating wire 2, and a ceramic such as magnesia is used as the insulator 3. Further, the metal sheath 4 is made of Inconel, and the outer diameter of the electric heater wire 1, that is, the finished outer diameter of the metal sheath is 1.0 mm.

The electric heater wire 1 is wound around the surface of the support 5. Since the electric heater wire 1 has a small outer diameter and is highly flexible, it can be freely bent and wired in any shape.

The method of attaching the heater wire 1 to the base 5 can be either by temporarily fixing the electric heater wire 1 to the base 5 with adhesive, or by tying the electric heater wire 1 to the base 5 with thin metal wire, etc. Any method may be used as long as the electric heater wire 1 can be fixed to the support body 5 during the thermal spray coating treatment described below. Of course, it is also possible to wrap a thin metal wire around the electric heater wire 1 in advance, or to insert a small ring-shaped plate or wire through it, and to weld or adhere the thin wire or ring to the base.

Here, the support body 5 is a net-like and hemispherical support body 51,5.
2, and electric heater wires 31 are wired along the outer peripheral surfaces of these supports 51 and 52.

In the embodiment, the net-like supports 51 and 52 have a structure in which the doors can be opened left and right by hinges (not shown). Therefore, when the net-like support 5 (51, 52, the same applies hereinafter) is closed, the object to be heated (not shown) housed inside can be heated from the entire circumference of the spherical heater.

When the support body 5 is made into a net-like support body, the electric heating device becomes lightweight. Furthermore, since the mesh support 5 is easy to mold, it is easy to form a heating element in a shape suited to the purpose. Further, since the mesh-like support 5 allows the sprayed film member 6 to enter into the mesh and enhance the anchoring effect, the sprayed film member 6 is firmly fixed to the support 5. Furthermore, the space between the outside (i.e., the outside of the sphere) and the inside (i.e., the inside of the sphere) of the net-like support 5 can be made into a net-like shape even after the thermal spray coating treatment, so that there is no mesh (empty). Gas, air, and fluid can pass through it. As a result, heating of the object to be heated in a vacuum or under gas flow is facilitated.

In the above embodiment, the net-like supports 5 and the electric heater 1 are separate, but the electric heater wire 1 may constitute a part or the front part of the net-like supports 51 and 52.

Further, the net-like support 5 includes a support having a mesh-like small hole.

Furthermore, the shape of the support body 5 can be made into various shapes other than a sphere depending on the purpose.

As described above, the electric heater wire 1 provided on the support body 5 is thermally sprayed with a nichrome-based thermal spraying material from the outside, and the support body 5 and the electric heater wire 1 are coated with the thermal spray coating member 6. The thermal spraying method may be a known flame spraying method or another thermal spraying method such as a plasma spraying method. The sprayed film thickness is, for example, approximately 1 mm. Of course, depending on the purpose, the thickness of the sprayed film can be made thinner or thicker to about several mm.

Further, the thermal spraying material is not limited to nichrome-based metal materials, and various inorganic and organic thermal spraying materials such as ceramic materials made by known techniques can be arbitrarily selected from the viewpoints of workability, heat resistance, economic efficiency, etc. However, a metal sprayed film is preferable because the heat spreads laterally and uniform heating can be performed.

Note that even if the sprayed film member is sprayed from a direction perpendicular to the surface of the support 5 on which the sprayed film member 6 is applied,
Alternatively, it may be performed obliquely to the surface to be adhered.

The heat-generating heater body formed as described above is then covered with a heat insulator 8 such as glass wool, and then housed in a metal case (not shown) or the like.

7 illustrates a cube as an object to be heated. In addition, a power supply device (not shown) is connected to the electric heater wire 1, and the electric heater wire 1
controlling the current flowing through by a known control means,
Temperature control is performed as an electric heating device.

According to the above embodiment, the electric heater wire 1 generates heat by itself when a heating current is applied thereto. At this time, since the electric heater wire 1 has a small outer diameter and is highly flexible, it can be placed at an optimal position along the shape of the base 5, and can be placed evenly or intentionally over the entire surface of the base 5. They are installed with varying density. Therefore, the object to be heated (not shown) set inside the support body 5 can be heated uniformly from the entire circumference of the object to be heated 7 or with a desired temperature distribution. It becomes possible.

Note that when the electric heater wire 1 and the support body 5 are covered with a sprayed film member 6 having a sufficient thickness, the electric heater wire 1
The heat generated from A heating effect acts on the object from all around it.

In addition, the sprayed film member 6 is placed on the electric heater wire 1.
When the heat rays on the shorter wavelength side generated by the electric heater wire 1 are deposited by about several mm, they are absorbed by the sprayed film member 6, and the object to be heated 7 is no longer irradiated directly.

Furthermore, as described above, since the sprayed film member 6 surrounds the electric heater wire 1, the electric heater wire 1
The generated heat is effectively dispersed to the surrounding thermal sprayed film member 6 and support body 5. Therefore, the thermal resistance between the metal sheath 4 of the electric heater wire 1 and the support body 5 becomes a sufficiently small value. That is, the temperature difference between the metal outer skin 4 and the support body 5 becomes smaller. As a result, the entire support body 5 acts as a heat generating body, so that the heat capacity as a heat generating source is expanded.

On the other hand, since the distance between the electric heater wire 1 and the metal sheath 4 can be reduced as will be described later, the thermal resistance between the heating wire 2 and the metal sheath 4 is also reduced. the result,
The temperature difference between the heating wire 2 and the support body 5 is also reduced. Therefore, there is no need to pass an excessive current through the heating wire 2 as in the prior art, and a high so-called watt density can be achieved. As a result, the heating wire 2
There is no risk of deterioration of the heating wire due to excessive heating of the wire itself.

By the way, it is generally known that the smoke saving resistance or withstand voltage of the insulating material 3 decreases as the temperature increases. However, in the above embodiment, the heating wire 2
Since there is no need to excessively heat the heating wire, the temperature of the heating wire is lower than that of the prior art. As a result, the insulation resistance and withstand voltage of the insulator 4 do not decrease, so the thickness of the insulator 4 can be made thinner, and the electric heater wire 1 can be easily bent, even if the support 5 has a complicated shape. The electric heater wire 1 can be optimally attached along the surface of the support body 5 even when

Therefore, according to this embodiment, when heating the object to be heated, the electric heater wire 1, the support body 5, and the sprayed film member 6 all act as heating elements, and the object to be heated 7 is evenly heated from the entire surrounding area. Therefore, there is no need for a heat equalizing plate or the like as in the prior art. As a result, the electric heating device can be configured to be small and lightweight.

In the above description of the embodiments, the supports were exemplified as stainless steel nets, and these supports were described as being covered with a thermally sprayed film member together with electric heater wires.
The support body can also be formed from paper, wax, plastic, or the like. In this way, after wiring the electric heater wire to the base made of paper etc.,
By applying the sprayed film to the base together with the electric heater wire, and then burning the base or removing only the base, it is possible to create an electric heating device in which only the electric heater wire is coated with the sprayed film. Can be configured.

The electric heater constructed in this manner and equipped with a sprayed film member in the form of a replica of the base, so to speak,
Although the heat capacity of the heating element is small, the heating of the heated object is equalized by the sprayed film member, so the heated object can be heated evenly, and heating and cooling can be performed with a fast response speed. I can do it.

Note that the present invention is not limited to the above-mentioned embodiments, but can be applied to various types of heaters.

[Effects of the invention] As described above, according to the invention, since the support body to which the electric heater wire is attached has a net-like small hole, it is possible to reduce the weight of the device and to improve the anchoring effect of the sprayed film member. Enables firm adhesion of the high-temperature electric heater wire and the sprayed film member.

[Brief explanation of the drawing]

FIG. 1 is an external view of main parts showing an embodiment of the present invention. 1... Electric heater wire, 5, 51, 52... Support body, 6... Thermal spraying member.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) An electric heater wire, a support for supporting the electric heater wire having small mesh-like holes on its outer circumferential surface, and thermal spraying applied to the electric heater wire and the support. An electric heating device characterized by comprising a membrane member. (2) The electric heating device according to claim 1, wherein the support body is made of a net material. (3) The electric heating device according to claim 1, wherein the base body is formed of a base body that can be removed after the thermal sprayed member is applied. (4) The electric heating device according to claim 1, 2 or 3, wherein the sprayed film member is a metal sprayed film.