JPS58212092A - 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 The present invention comprises: 1. It relates to a high-frequency heating device in which the oscillation frequency of the high-frequency heating heat source is the 916 MHz band, which is one of the S, M, (industrial, scientific, and medical) frequency bands,
More specifically, the present invention relates to a high-frequency heating device that has an improved heating chamber configuration for accommodating an object to be heated using high-frequency waves.

Microwave ovens, which are typical examples of conventional high-frequency heating devices, are I,
The 2460 MHz band, which is one of the S, M, frequency bands, is used for the generation of high-frequency heating heat sources. j-
When using the heat chamber configuration, there are 1.

Each of the JJII heat chambers/r method (width/1° method, depth/1゛ method,
This heating chamber excitation wave invasion (approximately 12crr
F12 to 3 times as much as L), 1- because it violates the law,
In this heating chamber? luInside the heating chamber when heated items are stored/
1;, the electric field distribution i takes the form j+li/I). Here, the electric field (1) obtained by 4 is not a distribution that can efficiently heat the object to be heated (high-frequency JJII), but may be referred to as local JJII heat. For this reason, microwave ovens are equipped with stirrer fans, which are installed in the heating chamber to forcibly disturb the electric field distribution.11. ) I+' of the heated object to prevent spot heating 11! Measures such as turning it around once were taken, and it was an extremely powerful mechanism.

In view of these points, the present invention compares the fixed frequency of high frequency C1 heat heat 1 with the dimensions of a practical heating chamber: [,
The 916 MHz band, which is one of the S, M, frequency bands, is selected.The dimensions of the heel heating chamber are appropriately selected, and the electric field distribution generated within the heating chamber is limited.

The first purpose is to make the heating chamber configuration two-dimensional, easy to manage, and practical. There are no standing waves in the room height direction. In other words, the heating chamber is configured such that an electric field distribution T E, zo+ 7-d, which is uniform in the height direction, basically occurs.

The second purpose is to accommodate the heated object (1'/i
T F so that high frequency heating can be performed efficiently regardless of
, The dimensions in the height direction of the heating chamber are defined so that the TE111 mode, which has a shape different from the electric field distribution in the 201 mode and has a width of 4J, is generated.

As a third purpose, in order to efficiently apply high frequency heating according to the size of the object to be heated, according to the object to be heated,] 2.2.
The two electric field distributions are switched and selected.

The present invention will now be described with reference to the drawings. FIG. 1 is a diagram showing heating chamber special feature 1 using the electric field distribution generated in the heating chamber and the position and amount of the object to be heated as parameters.

In figures (a) and (b), 1 is T R2o+-r
Need, 2 indicates TE+++ mode, 3 indicates T li:
2 (Heating chamber excitation antenna during N mode excitation, 4 is T
This is a heating chamber excitation antenna during E+++ mode excitation. In addition, the width of the heating chamber (1° measurement W) is 36 m, and the height dimension H is 19 (
The heating chamber characteristics when ll'm and depth θ are 37cIn (shown in Figure C1).

In Figure 101, the h1°l axis indicates the heating chamber resonance frequency, and the vertical axis indicates negative 4+1 jlj. The ΔJ band is the 915 MHz band. Here, water load is used as the load. (&) The figure shows when the water load is placed at the center of the bottom wall of the heating chamber, and (b
) The figure shows the case when two pieces are lined up on the center line (center line with respect to the room running direction).

Here, the characteristics will be explained. In 11, the heating chamber resonance frequency will be explained.

1. (As a realistic interpretation, consider the case where there is no object to be heated in the heating chamber.

If the heating chamber is an ideal cavity resonator consisting of a large-sided body, the resonant frequency f of the heating chamber is given by: Here, V is the speed of light, and W, H, and D are the width, height, and depth of the heating chamber, respectively, in m.

n and s are the number of standing waves occurring in the width direction of each heating chamber, the number of standing waves occurring in the height direction, and the number of standing waves occurring in the depth direction, respectively.

In the heating chamber dimensions shown in Fig. 1, the resonance frequency of each mode at no load is TE2o+ of 926. I MHz, TK++
+ is 979.7M blood.

This heating chamber resonance frequency changes due to the presence of a dielectric object to be heated in the heating chamber. Since the object to be heated is a dielectric, wavelength compression occurs, so the resonant frequency changes toward the lower side.

This change characteristic is shown in Figure (C) using the amount of water load and the position where the load is placed as parameters.

By the way, this heating chamber resonance frequency is an important parameter for efficient high-frequency heating of the object to be heated. because,
When the heating chamber resonates, the most high-frequency power exists in the heating chamber in the frequency band near the resonant frequency, so the object to be heated can be heated faster with high-frequency waves. Looking at the characteristics, in TE+++ mode excitation, the change characteristics of the resonant frequency with respect to the position of the load are small compared to the Tg2o+ mode1.On the other hand, looking at the change in the resonant frequency with respect to the load amount, it is found that in the TE2o+ mode excitation There is very little change when the load is placed at approximately the medium heat area on the bottom wall of the heating chamber. The present invention integrates the features of both. In other words, when the object to be heated is placed only in the approximate center of the bottom wall of the heating chamber, T
Ezo+ mode excitation is caused by F-1 If a heated material is placed in a wide area within the bottom wall of the heating chamber, T E 2
This selects between o+ mode excitation and TE+++ mode excitation.

FIG. 2 is a configuration diagram of a high frequency heating device showing an embodiment of the present invention.

The heating chamber 6 that accommodates the object to be heated (not shown) has 9
It has a bottom wall surface configured to generate the TE2 old mode with no standing waves in the height direction in the 1 s MHz frequency band, and the height of the object to be heated is approximately the height of the heating chamber. 916 M when the water load is approximately 1000 cc in half.
It has a structure in which the dimensions in the height direction are determined so that the heating chamber resonates in the TKN+ mode at Hz. The high frequency power generated by the high frequency heating heat source 6 having an oscillation frequency in the 915 MHz band is radiated into the heating chamber from the heating chamber excitation antenna 7 or 8 which is selected depending on the object to be heated. Reference numeral 9 denotes a coaxial changeover switch for selecting and switching between the two force vibration antennas. The figure shows a state in which TE2o+ mode excitation is performed.

The control signal for this coaxial changeover switch may be input manually by the user, or the size of the object to be heated may be automatically detected and the control signal automatically input.

The present invention has the following features: 1. S, M, 91 which is one of the frequency bands
In a high-frequency heating device having an oscillation frequency of sMHz, T in the frequency band is taken into account the dimension in the height direction of the heating chamber where the 'II T g 201 mode occurs, which does not have a standing wave in the height direction of the heating chamber in the frequency band. The dimensions produced by the E111 mode were defined, and these two modes were selectively switched depending on the object to be heated. 1b frequency heating device is provided, and (1) it is possible to grasp the 0(2)′ electric field distribution that allows highly efficient high-frequency heating to decrease by 1r depending on the object to be heated and the storage position of the object to be heated. Ease of use is good.

(3) Since it is based on TR2o+ mode, it is easy to manage the dimensions of the heating chamber in the height direction.

(4) Desired TE++ can be achieved by simply specifying the height dimension appropriately.
+ mode can be generated. -': 9 effects are achieved.

[Brief explanation of the drawing]

Figure 1 shows the electric field distribution generated in the heating chamber and the object to be heated.
Fig. 2 is a +1/# diagram of the high-frequency heating system according to an embodiment of the present invention; , 6... High frequency heating heat source having an oscillation frequency in the 915 MH2 band, 9...
Coaxial changeover switch. '1・□ Name of agent Patent attorney Toshio Nakao and 1 other person 1st
Figure 2 country

Claims (1)

[Claims] 1, S, M, a high frequency heating heat source having an oscillation frequency in the 915 MHz band, which is one of the frequency bands, and a heating chamber that produces a TE2φ1 mode having no standing waves in the height direction in the frequency band. 1)i (TK+ in the heating chamber) in the frequency band;
++ mode, and selects and controls the following two modes depending on the object to be heated accommodated in the heating chamber.