JPS61240589A - High frequency 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 the Invention The present invention relates to an apparatus for cooking and heating foods and the like using microwave energy.

2. Description of the Related Art Among conventional high-frequency heating devices, a microwave oven is a typical device for thawing and cooking. When defrosting and cooking using this microwave oven, since the food to be heated is either frozen or frozen, it is difficult for the microwave energy to penetrate into the inside of the food, and local heating may occur on the surface of the food. Because it is easy to heat, a unique microwave heating method is used that effectively utilizes heat conduction on the surface of the heated object.

By the way, since microwave ovens emit microwave energy into the heating chamber, it is impossible to concentrate the microwave energy on the frozen food, and most of the microwave energy is emitted from the frozen food. The radio waves are reflected back to the radio wave source outside the heating chamber without being absorbed by the radio waves.

The amount of microwave energy that contributes to cooking, defrosting, and cooking is negligible.

On the other hand, there is a technique in which microwave energy is concentrated in a microwave transmission space and a heated object is placed in the space where the microwave energy is concentrated.

Such technologies are referred to as microwave transmission lines, surface wave lines, or slow wave circuits.

JP-A-49-16944 discloses an application of this type of technology to a high-frequency heating device. The content of this publication discloses a configuration in which a ridge (=J ladder circuit) is arranged and an object to be heated placed near this ladder circuit is heated.However, this publication uses a ridge waveguide as a microwave transmission path. Because of the use of ridge waveguides, the structure is large and has multiple shoulders.Also, since the space for concentrating microwave energy is a ridge waveguide, there is a disadvantage that the space for energy concentration is restricted.

As an improvement on the shortcomings of the above publication,
There is a publication No. 1312. This publication discloses a configuration in which a planar slow-wave circuit including a plurality of interdigitated tape lines is arranged, and an object to be heated placed near the tape lines is heated.

However, as is clear from the specification of the publication, a slow wave circuit alone cannot effectively heat a thick object. To prevent this, Publication No. 1 discloses a structure in which a part of the microwave energy generated by the radio wave source is released into the heating chamber from the slow wave circuit and the branched electric 'e' and the path system (q = 1). Device 1゛1” + 19,1 large size, double X
There are some drawbacks that lead to I-ization.

Indeed, since the main purpose of the above two public flJ is to brown the surface of the heated object, the microwave energy is concentrated in the space near the installed microwave transmission line, and This makes the electric field strength in that space extremely strong. This is also one of the reasons why a thick object to be heated may not be heated properly.

The main purpose of conventional microwave transmission lines that concentrate microwave energy is to brown the surface of the food, so the energy concentration space is was near a microwave transmission line. For this reason, in order to heat the whole thick food, a means for radiating microwave energy into the heating chamber is also used, which poses problems in that the structure of the apparatus becomes complicated and large.

Kihatsu U3Aia solves these problems, and uses a transmission line with a simple configuration that transmits microwave energy while radiating it, and moves the radiating part in time to transmit microwave energy to the entire food. The present invention provides a high frequency heating device that can effectively perform diffusion.

Means for Solving the Problems The high-frequency heating device of the present invention provides a planar circuit consisting of a cross-finger tape line for coupling microwave energy generated by a radio wave source, which is connected to the bottom wall of the heating chamber at a predetermined distance from the bottom wall. In the space created by the bottom wall of the heating chamber and the planar circuit, an impedance variable section that temporally varies the impedance of at least the terminal end of the intersecting finger line is arranged, and the planar circuit It is a device designed to heat food placed on the side.

Function: The high-frequency heating device of the present invention has an intersecting finger portion disposed below the food, which covers the area where the food, which is a standard-sized object to be heated with respect to the volume of the heating chamber, is placed. The finger tape line transmits microwave energy while radiating the microwave energy toward the food using the bottom wall of the heating chamber as a reflector.

The radiation distribution of microwave energy is determined by the standing waves generated within the tape line. This standing wave is uniquely determined by the type and size of the food and the position of the point of large impedance change in the tape line, and is strong from the tape line part where the voltage is maximum in the standing wave distribution that occurs. Produces energy radiation. The impedance variable section temporally moves the point of large impedance change within the tape line, and temporally changes the standing wave distribution generated within the tape line due to the interaction with the heated food, producing strong energy. Transferring the part that emits radiation to the entire food product:
<It has the effect of diffusing microwave energy.

EXAMPLE Hereinafter, a high frequency heating device according to an example of the present invention will be explained with reference to the drawings.

FIG. 1 is a partially cutaway cross-sectional configuration diagram of a high-frequency heating device showing an embodiment of the present invention, and FIG. 2 is a diagram showing an example of the configuration of the main parts of FIG. 1.

In the figure, 1 is a door, and 2 is a heating chamber, which is formed by a space 3 and a space 4 for accommodating objects to be heated.

Reference numeral 5 denotes a cup of the main body of the apparatus, which also serves as a wall surface of the heating chamber.

6 is a radio wave generation source that generates microwave energy;
For example, the solid-state element is configured as a UJ element. 7
It is a planar circuit in which a cross-finger tape track 8 is arranged,
They are arranged substantially parallel to the bottom wall surface 9 of the heating chamber at a predetermined distance. 1o, 11-: A coaxial transmission line cable and a droplet trip line, respectively, which transmit microwave energy generated by a radio wave generation source approximately at the center of the intersecting tape line of the planar circuit. Reference numeral 12 denotes an impedance variable section, which is provided in a space created by the planar circuit 7 and the bottom wall surface 9 of the heating chamber.

13 is a mounting plate made of ceramic or resin on which an object to be heated (not shown) is placed; support material 14.
15, it is arranged at a predetermined distance from the planar circuit.

Reference numeral 16 denotes a cooling fan that also serves as cooling means for the radio wave generation source, and the air current generated by this fan flows into the space 3 through an air guide 17 provided in the space 4 and the support member 15. At this time, the impedance variable section rotates due to this wind flow, and the point of large impedance change within the tape line is moved.

The interdigital tape line 8 has a tooth profile pitch p and an interval W between the tooth profiles of p = 2 w, and a part of each corner of the tooth profile (
(representatively shown as 18) is a straight line section (representatively shown as 19)
Processing 1 (45° cut (representatively shown as 20) at 21×1) is performed to reduce the change in impedance between the two and transmit the microwave energy smoothly.

The variable impedance section 12 has a main body frame that supports the central axis of rotation 21 by the ground tooth profile 22 forming the interdigitated tape line and the bottom wall surface 9 of the heating chamber, which has a low conduction loss. It is made of resin material, and is lightweight to enable smooth rotation due to wind flow.

This main body consists of three blade parts 23, 24, and 25, one of which is provided with a metal cover (indicated by the hatched part in FIG. 2) that covers a framework made of resin material. The impedance of the interdigitated tape line located on one side of the blade section 23 provided with this metal cover is much lower than that where the blade section 23 is not provided.

If there is no variable impedance section, the open configuration of the terminal end 26 of the tape line causes the terminal end to become a point of large impedance change, and a standing wave starting from this point will be generated within the tape line. When two series of impedance variable parts are added, a standing wave is generated starting from the tape line above the vane where the metal commer is provided, or from the end of the tape line when there is no tape line on one side. Occurs within the tape track.・When the blade of the metal cover is located below the end of the tape line on the front roller, a standing wave is generated starting from the end, but the tape line on one side of the blade has a small impedance. Therefore, although the origin of the standing wave is the same, the portion of the tape line that radiates strong microwave energy is
It becomes 2 if the radiation part is different in case of 2.

As the variable impedance section rotates, the strong microwave energy radiating section of Kadako moves over a wider range, allowing the microwave energy to be efficiently diffused throughout the food, resulting in less effective heating. Ru.

Note that the impedance variable section is not limited to the first embodiment, and for example, a solenoid coil may be used to connect between the teeth of the paulownia tape line, or inserted into the interval W between the teeth. It may be a configuration.

Furthermore, the treatment of a part of the corner of the tape line, and the relationship between the tooth profile pitch p and the interval W between the tooth profiles, p-=2w.

The arrangement of the intersecting fingers is not limited to the one embodiment of the present invention, and any configuration may be used as long as the arrangement allows energy to be transmitted while radiating energy at the end of the tape line.

Effects of the Invention As described above, the high frequency heating dose-1 of the present invention has the following effects.

(1) The energy transmission path and the radiation system can be configured as a single planar circuit.It has a simple structure.

(2) Excitation is easy.

(3) The microwave energy radiating part can be moved over a wide range with a simple configuration, and the entire food can be heated efficiently and uniformly.

(4) Since the cooling air of the radio wave generation source is used as the power source for moving the microwave energy radiating section, energy can be saved.

(5) Since the cooling air flows into the heating chamber with oil, it is possible to suppress the temperature rise of the variable impedance section, the plane circuit, or the bottom wall of the heating chamber, and the amount of heat generated can be mixed with the cooling air and sprayed onto the food. It can be heated efficiently.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway cross-sectional configuration diagram of a high-frequency heating device showing an embodiment of the present invention, and FIG. 2 is a configuration diagram of the main parts of FIG. 1. 2.3.4... Heating chamber, 6... Radio wave generation source, 7... Planar circuit, 8... Cross finger tape line, 9... ...Heating chamber bottom wall surface, 12...
. . . variable impedance section, 26 . . . termination section. Name of agent: Patent attorney Toshio Nakao and one other person
R-

Claims (1)

[Claims] a heating chamber for accommodating an object to be heated; a planar circuit consisting of an interdigitated tape line arranged approximately parallel to the bottom wall at a predetermined interval from a bottom wall forming the heating chamber; and the interdigitated tape line. a radio wave generation source that generates microwave energy coupled to a substantially central portion of the heating chamber; and a radio wave generation source that generates microwave energy coupled to a substantially central portion of the heating chamber; A high-frequency heating device consisting of an impedance variable section that changes impedance over time.