JPS585841Y2 - High frequency heating device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a high-frequency heating device that can perform roasting or browning with a gas burner and heating with high-frequency power at the same time.

High-frequency heating devices such as microwave ovens that heat food using high-frequency energy use high frequencies of about 2450 MHz to cook food, and have the advantage of being able to cook food quickly and hygienically. It has the disadvantage that it cannot be burnt.

One way to overcome this drawback is to place an electric heater inside the heating chamber and heat the food using radiant heat generated by the heater to brown the food, but such conventional methods produce a large amount of heat. As a result, the temperature rise performance was poor, and it took 9 hours to brown the food (not only did it take 9 hours to brown the food), but it was also impossible to uniformly brown the food.

On the other hand, there is a method that utilizes the heat of combustion of a gas with a large calorific value as a method for uniformly roasting and burning in a short period of time.

In other words, there is a method in which a gas burner is placed in a part of the high-frequency heating chamber and food is heated with radiant heat from the combustion of gas.

In this method, to ignite the gas burning on the burner surface, a pair of discharge poles is formed by an electrode protruding from one end of the heating chamber and an electrode facing it, and a high voltage is applied to this to create a continuous spark. A common method is to generate a gas and ignite it using the discharge energy.

The tip of one piece of this stacked pole protrudes into the heating chamber, the central part is attached to the heating chamber wall via an insulator, and the other end is arranged outside the heating chamber so that it is connected to a high voltage transformer. It is.

In the Shikajika-ru method, when the electrode tip is in the presence of high-frequency energy, such as during high-frequency heating, the high-frequency energy is transmitted to the outside of the heating chamber using this electrode as a transmission line and leaks, so this is absorbed outside the heating chamber. It is necessary to take safety measures, such as installing a mechanism to prevent this, but these measures are complicated and expensive, and have the disadvantage that they do not provide a sufficient radio wave absorption effect.

Similarly, when a flame rod for detecting the presence or absence of flame is protruded from the burner surface, radio wave leakage and countermeasures are required.

For this reason, as shown in Figure 1, it is conceivable to cover everything that could be a source of radio wave leakage, such as the burner combustion section 9 simmering device 9 ignition confirmation device, with a means to block high-frequency radio waves, such as wire mesh or punched metal.

To briefly explain the structure shown in Fig. 1, there is a heating chamber 2 surrounded by a wall 1 mainly made of metal plates, and a magnetron 3 at the top for supplying high frequency energy into the heating chamber. There is a waveguide 4, and a door 5 for closing the heating chamber is arranged at the front of the heating chamber.

A gas burner 6 is arranged on the ceiling of the heating chamber 2, and serves as a mechanism for heating a turntable 7 arranged in the heating chamber 2 and food 9 placed on a saucer 8.

The burner 6 is composed of a metal case 10, a passage section 11 for a mixture of gas and primary air, and a porous ceramic plate 12, and the gas is burned on the surface of the ceramic.

This burner 6 is supported by a burner support part 13 of the heating chamber, and a discharge electrode (earth side) 14 is arranged at one end of the burner support part 13.

On the other hand, the distance between the electrodes facing this discharge electrode 14 is 4 to 5 mm.
There is another discharge pole 15 located across from it.

A voltage of 15 KV generated by a high voltage transformer (not shown) is applied between the discharge poles 14 and 15, and a discharge occurs between the two poles.

16 is a ceramic rod that supports the electrode 15 and is electrically insulated from the heating chamber wall 1. A metal rod for electrode passes through the center, and the end 17 of the electrode is extended to the outside of the heating chamber.

The end portion 17 of this electrode is electrically connected to the high voltage transformer.

18 is a turnchie pull drive motor, 19 is a punching metal for shielding radio waves, and 20 is a waveguide opening.

However, doing so also impedes the passage of radiant heat energy generated in the combustion section, making the highly efficient burnt date disadvantageous for realizing heating.

Therefore, the present invention takes measures to prevent radio wave leakage from the main gas burner and exposes it to high-frequency radio waves inside the heating chamber.On the other hand, the spark generation electrode and flame detection electrode are cut off from high-frequency radio waves by punching metal etc. It is surrounded by a means that allows gas and flame to pass through and is placed close to the combustion part of the gas burner, so that the gas burner can be ignited and its ignition can be confirmed without the risk of radio wave leakage, and the radiant heat energy generated in the burner is Make sure that the irradiation is applied directly to the object to be heated.

Figure 2 is a sectional view of the main parts showing one embodiment of the present invention.
Reference numeral 21 denotes a shield case made of punched metal that shields the discharge poles 14 and 15 for generating sparks from high-frequency radio waves.

The size of the pores of this shield case 21 is 3 to 3 mm in diameter.
It is about 5 mm.

The gas flowing into the shield case 21 through the pores is caused to be attached by the sparks of the discharge electrodes, and at the same time, the flame is transferred to the porous ceramic plate 12 which is the combustion part of the burner 6.

□Figure 3 explains the radio wave leakage prevention structure of the gas burner 6. By appropriately setting the diameter d and length l of the gas inlet 23 facing the gas nozzle 22, the radio wave leakage prevention structure against high frequency radio waves can be achieved. can do.

Incidentally, if the frequency of the high-frequency radio waves used is 2450 MHz, d ~ 10 ~ 20 mm, l ~ 15 ~ 20 m
If m is also sufficient, a sufficient cutoff effect will occur.

Incidentally, if no protrusions or the like are provided on the inner surface of the gas burner, generation of sparks within the gas burner can be completely avoided.

``With this configuration, the food is stored in the heating chamber 2, and the gas burner 6 is ignited.

When the fuel gas is ejected from the gas nozzle 22, it draws in surrounding air, flows into the gas inlet, and fills the gas burner 6.

The mixed gas of fuel and air flowing out from the porous ceramic plate j2 also flows into the shield case 21 that covers the electrodes, and is ignited by the sparks produced at the tips of the electrodes, and at the same time the porous ceramic plate It also migrates to the 12th surface and starts burning.

This combustion generates radiant heat and starts cooking the food.

In addition, if a flame detection electrode is installed in the shield case 21 at a position exposed to the flame generated by the gas burner mentioned above to detect the start of combustion, automatic control of the generation of discharge sparks is possible. There is.

After this point, if the door 5 is closed and the magnetron 3 is oscillated to supply high-frequency power into the heating chamber 2, heating and cooking can proceed together with the heating by the gas burner 1 described above.

Here, although the gas burner 6 is exposed to high-frequency radio waves, the entire case 10 is made of metal, and the gas inlet portion 2
Since the diameter and length of '3 are selected as cut-off dimensions for high frequency radio waves, radio waves will not leak through this burner.

Furthermore, since the ignition function is obtained with the ignition discharge poles 14 and 15 shielded from radio waves by the punched metal shield case 21, radio waves will not leak through these discharge poles.

Although the above embodiment does not explain the case where the flame detection electrode is installed, the flame detection electrode is installed in the part of the shield case 21 where the flame of the gas burner reaches, and the heating can be detected depending on the presence or absence of the flame. It is possible to perform control such as fuel gas supply control or high frequency heating control.

As described above, the present invention installs a gas burner in a part of the heating chamber where it is exposed to high-frequency radio waves, makes the case of the gas burner from metal, and selects the gas inflow part with cut-off dimensions for the radio waves used. In addition, the discharge electrodes for spark generation and the electrodes for flame detection are placed close to the combustion part of the gas burner by being surrounded by a means that blocks high-frequency radio waves, such as punched metal, and allows the gas and flame of the gas burner to pass through, thereby preventing radio wave leakage. It is possible to ignite a gas burner and confirm its ignition without the risk of causing a fire.

Furthermore, since there is no obstruction between the gas burner combustion surface and the food, efficient heating can be achieved.

[Brief explanation of the drawing]

Figure 1 is a sectional view explaining the prior art, Figures 2 and 3.
The figure is a sectional view of a main part of the present invention - an embodiment. 6... Gas burner, 9... Food, 10
...Metal case, 12...Porous ceramic plate, 14.15...Discharge electrode, 21...
...Shield case, 23...Gas inflow section.

Claims (1)

[Scope of utility model registration request] It has a high-frequency heating chamber for heating food with high-frequency energy, a door for closing the high-frequency heating chamber, a high-frequency oscillator, and a food mounting table made of a heat-resistant material disposed in the high-frequency heating chamber, In a high-frequency heating device in which a gas burner is disposed in a part of the heating chamber, and the combustion heat of the gas is used to roast or brown food, the combustion part of the gas burner is exposed to high-frequency radio waves, and the burner is The case is made of metal, and the gas inlet at the end of the case is made of high-frequency radio waves to create a cut-off structure, and the spark generation electrode and flame detection electrode for igniting the gas burner are made of punched metal or other high-frequency radio waves. A high-frequency heating device characterized in that the high-frequency heating device is provided close to the combustion section of the gas burner, surrounding it with a means for shielding the gas burner and passing the flame generated in the gas burner.