JPH05299170A - Hot-air combustion apparatus using dielectric heating element - Google Patents

Abstract

PURPOSE:To improve energy conversion efficiency and save energy by heating a dielectric heating element provided in a heating chamber with microwaves from microwave oscillating devices, and making the space of the heating chamber a high-temperature atmosphere. CONSTITUTION:A dielectric heating element 3 is divided into three groups 3a, 3b, 3c, and three microwave oscillating devices 4 corresponding to three groups 3a, 3b, 3c respectively are provided. When the operation of the device 4 is controlled, the heating place of the heating element groups 3a, 3b, 3c is properly set, and the temperature in a heating space 6 can be controlled in a wide range. A heating chamber 2 is communicated with a combustion chamber 12 via a nozzle section 11 formed by squeezing the space 6 into a small diameter, strong hot air is fed into the chamber 12, and the temperature distribution in the chamber 12 is unified. A blast means 5 is provided on a side wall 6r at the rear end of the chamber 2 via a blast pipe 13, and the blast pipe 13 is connected to a pipe 14 for feeding the air to a vent passage 8. A jet pump 15 for feeding the air to the space 6 is provided between the means 5 and the blast pipe 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a high temperature atmosphere heated by the heat generated by a dielectric heating element as a heat source,
Alternatively, the present invention relates to a hot air combustion device using a dielectric heating element, which is supplied as hot air into an incinerator such as a boiler.

[0002]

BACKGROUND OF THE INVENTION Conventionally, high-frequency radio waves, mainly microwaves (about 1 GHz to
The principle of dielectric heating, which radiates 30 GHz) to heat the substance by itself, has been widely and generally known. This principle has been widely used in various fields such as adhesion of microwave ovens and laminated single plate materials, sterilization of foods, and the like.

However, most of these have been used for the purpose of directly treating the processed substance by generating heat. What is used for other purposes is the heat itself generated by an object (dielectric heating element) that is heated by the dielectric heating principle, for example, as a heat source for an incinerator or boiler. It didn't happen very often.

By the way, theoretically, it is possible to obtain a heat generation temperature by dielectric heating up to a considerably high temperature of 2000 ° C. or higher, but there is no heat generating body capable of withstanding this, and this development has been awaited. However, in recent years, a heating element that enables this has been developed, and several cases have begun to appear. As an example of using this heating element, for example, a high temperature incinerator for waste of medical equipment is manufactured. In such an incinerator, a crucible-shaped melting furnace is made of a heat-resistant material such as ceramic, and a plurality of heating elements are embedded in the inner peripheral wall so as to be partially exposed. Then, the injection needle inside is melted.

[0005]

However, since such a melting furnace is arranged so as to be embedded in the inner peripheral surface, most of the transfer of thermal energy in the furnace is due to radiation and natural convection, so that the inside of the furnace is The space was naturally limited. Therefore, in order to use the furnace efficiently, the size of the waste is limited to 10 to 30 cm, and the waste that can be treated is also limited to the size. When it is used for a large waste incinerator and a large capacity boiler, the temperature gradient in the furnace becomes large and it is difficult to use. Further, it is obvious that the method of utilizing radiant heat as described above is not a good measure from the viewpoint of heating efficiency as well as the case of a large-scale furnace, and there is still a problem from saving electric energy.

Therefore, the present invention focuses on the high heat resistance of the dielectric heating element, and uses a high temperature atmosphere due to this heat generation as a heat source to replace the combustion apparatus used in the conventional incinerator and boiler. A hot air combustion device using a heating element is provided.

[0007]

In order to achieve the above object, a hot air combustion apparatus using a dielectric heating element of the present application is constructed as follows. A heat generating chamber whose inside is connected and opened to the combustion chamber, substantially the whole of which is formed of a radio wave permeable heat insulating material, and substantially the entire outside of which is covered with a radio wave shielding material, and an appropriate number of which are exposed in the space of the heat generating chamber. And a microwave oscillating device that is disposed outside the heat generating chamber where the radio wave shielding material is removed via a radio wave transmitting heat insulating material, and that supplies and radiates microwaves to the dielectric heat generating body. It is characterized by comprising an air blowing means for sending air into the heat generating chamber.

Further, if necessary, a ventilation path is provided so as to cover substantially the entire outer surface of the radio wave transmitting heat insulating material constituting the heat generating chamber, and a part or all of the ventilation is supplied to the heat generating chamber by the blowing means. You can Further, in order to blow out the hot air more strongly, the combustion chamber and the heat generating chamber may be connected via a nozzle.

[0009]

With this construction, the present invention operates as follows. The microwave radiated from the microwave oscillating device causes the dielectric heating element in the heating chamber to generate heat, and creates a high temperature atmosphere in the heating chamber space. At the same time, this high-temperature atmosphere is blown out as hot air into the combustion chamber, which is open for communication, by the air-blowing force generated by the operation of the air-blowing means. Further, in this case, stronger hot air is blown out through the nozzle to make the temperature distribution in the combustion chamber uniform.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one example of a concrete embodiment of the hot air combustion apparatus according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing the entire apparatus of the present embodiment, and FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 (without piping).

The device 1 of this embodiment is mainly composed of a heating chamber 2, a dielectric heating element 3, a microwave oscillating device 4, and a blowing means 5.
It consists of and. First, the heat generating chamber 2 is provided with a substantially cylindrical heat generating space 6 having a rectangular cross section inside, and is formed in a box shape by a radio wave transmitting heat insulating material 7 such as ceramic. And
The entire outer surface of the radio wave transmitting heat insulating material 7 is covered with a ventilation path 8 through which air mainly flows, and the entire outer surface thereof is covered with a radio wave shielding material 9 formed by a known technique such as a metal plate. ing. As a result, the heat in the heat generating space 6 is blocked to the outside, and the radiated microwave is prevented from leaking to the outside. The cross-sectional shape of the heat generating space 6 is not limited to the rectangular shape, and may be a circular shape or an elliptical shape as appropriate.

On the inner peripheral surface 6s of the heat generating space 6, a plurality of rod-shaped heat generating elements 3 having an appropriate length are embedded in the radio wave transmitting heat insulating material 7 at a part of one end thereof and most of the other part is exposed. As such, they are planted and arranged. The heating element 3 is planted from the inner peripheral surface 6s in the vertical and horizontal directions (in FIG. 2) toward the center, and is arranged in the horizontal direction in the inner peripheral surface 6s (in FIG. 1). Divided into 3 parts, 3 groups 3a, 3b, 3
It is divided into c.

The dielectric heating element 3 used here is
The one that meets the desired standard is appropriately selected from several types that currently exist, but by way of example, the desired name and "Arcabo" (manufacturer: Nara Seiki Co., Ltd.) were able to obtain the desired desired effect. Next, the microwave oscillating device 4 is made to correspond to the three groups 3a, 3b, 3c of the dielectric heating element 3 from the outside of the radio wave transmitting heat insulating material 7 which constitutes the heating chamber 2, and (in the drawing). It is arranged independently above and below. It should be noted that this arrangement is not limited to the upper and lower sides, and may be the upper, lower, left, or right sides. The microwave oscillating device 4 is configured using a magnetron, which is a known technique, and various control devices are arranged inside the microwave oscillating device 4. Therefore, the microwave oscillating device 4 is arranged outside the radio wave shield 7 which is less affected by heat. A waveguide 10 is connected to this, and is arranged outside the radio wave transmitting heat insulating material 7 excluding the radio wave shielding material 7 so as to open in a position direction corresponding to the dielectric heating element 3. Thereby, the microwave oscillated from the microwave oscillating device 4 is radiated to each dielectric heating element 3.

As described above, the reason why the heating elements 3 are divided into three groups and the microwave oscillating devices 4 corresponding to the respective groups are arranged is to control the operation of each microwave oscillating device 4. This is because the temperature inside the heat generating space 6 can be controlled in a wide range by appropriately setting the heat generating portion in each of the heat generating element groups 3a, 3b, 3c. Next, the heat generating chamber 2 is communicated with the combustion chamber 12 via a nozzle portion 11 formed by narrowing the space 6 to a small diameter. By providing the nozzle portion 11 in this way, strong hot air can be sent to the combustion chamber 12, and the temperature distribution in the combustion chamber 12 can be kept uniform.

Further, the right side wall 6r (on the drawing) thereof
A blower pipe 13 is communicated with the. The blower pipe 13 is communicated with the blower means 5 such as a blower. The blower means 5 is connected to the blower pipe 13 and a pipe 14 that mainly sends air to the ventilation path 8 for absorbing heat. Further, a jet pump 15 is provided between the blower unit 5 and the blower pipe 13.
Therefore, the heated air that has circulated in the ventilation path 8 is collected by the intake pipe 16 and is sent to the heat generating space 6 together with the air sent by the air blower 5. The reason why the jet pump 15 is used in this way is to avoid damage to the air supply unit 5 due to high temperature air.

As a result of the implementation of the hot air combustion apparatus 1 of the present embodiment configured as described above, the heat generation temperature of the dielectric heating element 3 reaches about 2000 ° C., and the air of the heating high temperature is sent to the blowing means 5.
When the air is blown into the combustion chamber 12 in the above, it can be proved that hot air having a temperature of about 1800 degrees can be obtained in the vicinity of the outlet of the nozzle portion 11 and can be sufficiently used as a heat source of an incinerator or a boiler. In addition, one heating element group 3a, 3b, 3c,
As a result of generating heat in two places and three places in each case, the hot air blown out is about 600 degrees, 1200 degrees, and 180 degrees, respectively.
It was 0 degree, and it was also proved that a wide range of temperature control was possible.

[0017]

[Effects] With the above structure, the present invention has the following effects. Since the dielectric heating element is used as a heat source, a high temperature can be obtained, and the energy conversion efficiency is high, so that energy can be saved. This leads to cost savings and has a great economic effect.

Further, various temperatures can be set by selecting the dielectric heating element, and it can be widely used as a combustion device for various incinerators and boilers. Furthermore, in addition to the heat insulating material, a ventilation path is provided, and the air ventilating there is warmed and sent to the heat generating space by the blowing means,
It is possible to reduce the internal temperature drop compared to blowing only the outside air. In principle, oxygen is not required to generate heat from the dielectric heating element, so the gas sent to the heating space need not be air, and combustion exhaust gas can be circulated and sent, resulting in better thermal efficiency. effective.

Furthermore, the hot-air combustion device of the present application does not require piping for supplying fuel or oxygen, and can be constructed in a simple and compact appearance. It could be widely used instead.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the entire device of this embodiment.

FIG. 2 is a sectional view taken along the line AA of FIG.

[Explanation of Reference Signs] 1 ... Device of the present embodiment 2 ... Heating chamber 3.
..Dielectric heating elements 3a, 3b, 3c ... Dielectric heating element group 4.
..Microwave oscillator 5 ... Blower 6 ... Heating space 6s
..Inner peripheral surface 6r..Right side wall 7 ... Radio wave transmitting heat insulating material
8 ... Ventilation path 9 ... Radio wave shielding material 10 ... Waveguide 11.
..Nozzle section 12 ... Combustion chamber 13 ... Blower tube 14
・ ・ Piping 15 ・ ・ ・ Jet pump 16 ・
..Suction tubes

Claims (3)

[Claims] 1. A heat-generating chamber (2), the inside of which is connected and opened to the inside of a combustion chamber, substantially the whole of which is formed of a radio wave permeable heat insulating material (7), and the outside of which is almost entirely covered with a radio wave shielding material (9). The dielectric heating element (3) which is appropriately exposed and arranged in the space of the heat generating chamber (2) and the radio wave transmitting property outside the heat generating chamber (2) where the radio wave shielding material (9) is removed. A microwave oscillating device (4) arranged via a heat insulating material (7) for supplying and radiating microwaves to the dielectric heating element (3), and a blowing means (5) for sending air into the heating chamber. A hot air combustor using a dielectric heating element. 2. A ventilation path (8) so as to cover substantially the entire outer surface of the radio wave transmitting heat insulating material (7) constituting the heat generating chamber (2).
2. The hot-air combustion apparatus using a dielectric heating element according to claim 1, wherein a part or all of the ventilation is supplied into the heating chamber (2) by the blower means (5). 3. A combustion chamber (12) and a heat generating chamber (2) are connected via a nozzle (11).
Or a hot air combustion device using the dielectric heating element according to 2.