JP3263627B2 - microwave - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a heating chamber for treating water vapor generated from an object to be heated in a microwave oven.

[0002]

2. Description of the Related Art Conventional heating systems for a microwave oven with a heater are roughly classified into two types. The schematic structures of these microwave ovens with a heater will be described with reference to FIGS.

[0003] First, each heater heating means will be described. FIG. 9 shows a hot-air circulation type microwave oven 1 in which heat from a convection heater 11 provided on the back of the heating chamber 6 is agitated and circulated into the heating chamber 6 by a convection fan 10. The air in the heating chamber 6 is supplied to the convection fan 10.
After being sucked from a suction port facing the center of the convection heater 11 and heated by the convection heater 11, it is discharged into the heating chamber 6 from a discharge port facing the outer periphery of the convection fan 10. Thereby, the air in the heating chamber 6 is stirred, and the temperature in the heating chamber 22 becomes uniform.

FIG. 10 shows a microwave oven 1 of an upper and lower heater type. An upper heater 12 is provided above a heating chamber 6 and a lower heater 1 is provided below the heating chamber 6.
3 are provided. Since the air in the heating chamber 6 circulates by natural convection, the temperature becomes uniform.

Next, the high frequency heating means will be described. FIG.
In the microwave oven, the magnetron 8 heats the object to be heated by supplying microwaves to the heating chamber 6. Heated
The temperature of the object gradually rises, and steam is generated from the surface of the object to be heated. When a large amount of the water vapor is generated, the water vapor adheres to the door 7 as water droplets, and the door 7 becomes cloudy. It is not preferable that the door 7 having a function as a see-through window becomes cloudy because the inside of the heating chamber 6 cannot be seen.

Therefore, in order to remove the water vapor generated in the heating chamber 6, a cooling fan 9 for cooling the magnetron 8 is provided.
The air blown by the heating chamber 6
Has been sent to. The flow of the air blown by the cooling fan 9 is indicated by solid arrows in FIG.

[0007] Then, the air intake is led into the exhaust duct 5 with the object to be heated or we generated steam passes through the exhaust duct 5, and is discharged from the exhaust port 2 provided on the back of the microwave oven to the outside . This is the general structure of a conventional microwave oven. This structure is the same regardless of which of the heater heating modes (hot air circulation, upper and lower heater system) shown in FIG. 9 or FIG. The dotted arrows shown in FIGS. 9 and 10 indicate the movement of air when the heater is heated.

[0008]

However, such a conventional example has the following problems. The intake port and the exhaust port provided for discharging the water vapor of the microwave heating become passages through which the high-temperature air in the heating chamber is heated to the outside when the heater is heated. Therefore, the rise of the temperature of the heating chamber 6 is deteriorated, and the thermal efficiency is reduced.

Further, since the maximum settable temperature of the heating chamber 6 is kept low, the temperature inside the heating chamber 6 cannot be set and maintained at a high temperature. This is because the temperature of the heating chamber 6 does not rise more than a certain degree because high-temperature air flows out to the outside. Normally, the maximum set temperature is about 250 ° C.

Further, in FIG. 9, the high-temperature air in the heating chamber 6 leaks from the intake port 15 when the heater is heated, and the temperature of the intake duct 4 becomes high. The operation panel 24 near the intake duct 4 is also exposed to a high-temperature atmosphere due to the heat. At this time, when the cooling fan 9 is rotated to cool the electronic components of the operation panel 24, there has been a problem that the temperature of the heating chamber 6 decreases and the temperature of the heating chamber 6 does not increase.

Furthermore, in such a conventional example, during microwave heating, an object to be heated is overheated due to an erroneous operation of a user or a trouble in equipment, and the object to be heated may be ignited in the worst case. Specifically, as shown in FIG.
The flame generated at step (1) leaks out of the microwave oven 1 from the exhaust port 2 on the back surface 1a of the microwave oven 1 through the exhaust duct 5. If there is a combustible material such as a curtain near the back surface 1a of the microwave oven 1, there is a danger that a flame may be transferred to the combustible and cause a fire.

Further, since the oil smoke generated from the object to be heated in the heating chamber 6 is released to the outside, the object near the exhaust port 2 is contaminated, and there is a possibility that the kitchen may have a bad smell. Furthermore, when the heater is heated, high-temperature air leaks from the exhaust port 2 to the outside, so that the surface temperature of the back surface 1a of the microwave oven 1 becomes high, causing burns, and melting or burning of objects placed nearby. Might be.

To solve this problem, Japanese Patent Laid-Open Publication No. HEI 6-185,734 discloses a method of closing the intake / exhaust port using a damper or the like. .

Japanese Patent Application Laid-Open No. 6-26651 discloses that
A countermeasure that circulates air in the heating chamber so as to obstruct the flow of air leaking out of the heating chamber without providing a damper is also shown. However, such a method that does not use a damper cannot completely prevent high-temperature air leaking to the outside, and does not provide sufficient heater heating performance such as thermal efficiency and rising temperature.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first aspect of the present invention is a microwave oven having high frequency heating means and heater heating means for heating an object to be heated in a heating chamber. In, an air inlet for sucking air containing water vapor generated from the object to be heated from above the heating chamber,
A duct for guiding the air sucked from the intake port, a discharge port for discharging the air passing through the duct from the lower portion of the heating chamber into the heating chamber, and an air sucked from the intake port through the duct for discharging the air from the discharge port. A circulation fan circulating in the heating chamber ,
The water condensed in the duct is supplied to the heater heating means.
It shall be the structure in which the humidification is supplied to the heating chamber during operation.

A second aspect is a high frequency heating means and a heater heating.
Microwave oven having means for heating an object to be heated in a heating chamber
The space containing water vapor generated from the object to be heated.
An intake port for taking in air from the upper part of the heating chamber, and the intake port
And a duct that guides the air taken in from
A discharge port for discharging air from a lower portion of the heating chamber into the heating chamber;
The air sucked from the air inlet is passed through the duct to the outlet.
A circulation fan circulating in the heating chamber.
Moisture that has condensed in the port is dropped through the
To you as having the configuration that leads to the bottom of the heating chamber.

According to a third aspect of the present invention, the air sucked into the duct is provided.
A humidity sensor for detecting humidity in the air;
When the humidity detected by the operator exceeds a predetermined value,
Ru to operate the ring fan. According to a fourth aspect of the present invention, there is provided a deodorizing device for deodorizing the air taken into the duct. Claim 5
A heat exchanger for exchanging heat with the air taken into the duct is installed.
Only that. Claim 6 is a method in which the suction port and the discharge port are heated.
It is arranged on the side of the room almost diagonally .

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a microwave oven according to the present invention will be described with reference to FIGS. The same parts as those in the above-described conventional example are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, an upper and lower heater type is described as a microwave oven, but the present invention can be similarly applied to a hot air circulation type.

<Embodiment 1> The microwave oven of the present invention circulates through the heating chamber 6 without providing an opening for exhausting the air in the heating chamber 6 to the outside. In FIG. 1, the microwave oven 1
The external air sucked from the suction port 27 at the bottom is blown to the magnetron 8 by the cooling fan 9, and the air that has cooled the magnetron 8 is discharged from the exhaust port 2 to the outside of the microwave oven 1. That is, unlike the conventional example, the air that has cooled the magnetron 8 is discharged to the outside of the microwave oven without being blown into the heating chamber 6.

Therefore, even if the cooling fan 9 is operated at the time of heating the heater, the temperature inside the heating chamber 6 is not lowered,
The electrical components mounted on the operation panel 24 can be cooled, thereby avoiding exposing the electronic components to a high-temperature atmosphere.

Most cooked foods that are often heated in a microwave oven are warmed, and their finishing temperature is 90 ° C.
It is as follows. Even if the temperature exceeds 90 ° C, 90
It is not necessary to continue heating at a temperature above ℃ for a long time. So 90
Since a large amount of water vapor is generated when the temperature becomes higher than ° C., it is determined based on the detection value of the humidity sensor 19 and the heating is stopped. Thereby, generation of a large amount of water vapor from the object to be cooked can be prevented.

That is, as shown in FIG. 8, when the heating target 23 is heated by the microwave power supply and the temperature gradually rises and the temperature of the heating target 23 approaches 80 ° C., a small amount of water vapor is generated from the heating target 23. At the beginning, the temperature reaches the detection level V1 of the humidity sensor at 90 ° C. Then, when the temperature of the object to be heated 23 reaches 100 ° C., steam is generated intensely.

As shown in FIG. 7, when microwave heating is instructed by a key operation on the operation panel 24, the microcomputer 25 turns on the relay L1. The cooling fan 9 operates and the magnetron 8 is cooled. The steam in the heating chamber is
Is detected by the humidity sensor 19 disposed in the first position. When the detection value of the humidity sensor 19 reaches a predetermined humidity level Vl, the microcomputer 25 turns on the relay L3. Then, the circulation fan 20 provided in the duct 22 operates and rotates.
Then, the air in the duct 22 is forcibly blown from top to bottom.

During the actual cooking, as described above, a large amount of water vapor is generated when the temperature of the object to be cooked 23 becomes close to 90 ° C. Since this is detected and the heating is stopped, the amount of water vapor is small and the door 7 has a small amount of water vapor. It can be used without hindrance because it can prevent fogging. Also, foods with a large amount of water vapor are usually covered with a wrap or a lid, so that the amount of water vapor is limited.

The water vapor generated from the article to be heated 23 is sucked through an oven inlet 15 formed above the heating chamber 6. A deodorizing device 18 is provided in a duct 22 near the oven air inlet 15 . The deodorizer 18 absorbs and decomposes odors and smoke. The deodorizer 18 decomposes and purifies smoke and odor by catalytic action.
It is disclosed in, for example, Japanese Patent No. 3534.

The air containing water vapor is guided by the circulation fan 20 and moves from the top to the bottom in the duct 22. At this time, when the high-temperature air containing water vapor passes through the inside of the duct 22, heat exchange occurs with the surface of the duct 22, and the temperature gradually decreases. As the temperature decreases, the amount of saturated water vapor decreases, and water droplets form on the duct 22 and condense.

The air having a reduced amount of water vapor is
It is sent into the heating chamber 6 again through the oven discharge port 16. In this manner, the air in the heating chamber 6 is circulated, and the cooking is performed.

<Second Embodiment> A microwave oven according to a second embodiment of the present invention has a structure similar to that of the first embodiment, and further includes a heat exchanger as shown in FIGS. 21 is provided in a duct 22.

Then, the warm air containing steam in the duct 22 is forcibly cooled by the heat exchanger 21 to reduce the amount of saturated steam and the amount of steam returning to the heating chamber 6. For example, a fin is provided as a heat exchanger 21 in a duct 22 as shown in the figure. Fins are also provided outside the heating chamber 6, and the fins are cooled by rotation of the circulation fan 20.

Although the above-described air cooling method may be used, an electronic electronic cooling method using the Peltier effect may be used. The heat exchanger 21 may be selectively operated according to the detection level Vl of the humidity sensor 19. With such a configuration, the air in the duct 22 can be cooled, the steam can be turned into water droplets, dehumidified, and sent to the heating chamber 6.

Third Embodiment The First or Second Embodiment
When the distance of the duct 22 is increased, the air cools well. Therefore, in Embodiment 3 of the present invention, FIG.
As shown in FIG. 3, air taken in through an oven inlet 15 formed near the ceiling on the back side of the heating chamber 6 is supplied to a door 7 at the lower part of the heating chamber.
It is discharged from the oven discharge port 16 formed on the side. That is,
On the diagonal line on the side of the heating chamber 6, the oven air inlet 15,
An oven discharge port 16 is provided. Thereby, the distance of the duct 22 can be secured long, and the dehumidifying effect is also increased.

As described above, in the microwave oven of the present invention, since there is no passage for air flowing from the heating chamber 6 to the outside, it is possible to completely prevent radio waves from leaking from the heating chamber 6 to the outside during microwave heating.

In the first to third embodiments, a configuration may be adopted in which the water vapor becomes water droplets, adheres to the duct 22, falls naturally, passes through the oven discharge port 16, and flows to the bottom of the heating chamber 6. Further, a water droplet receiver may be separately provided in the duct 22. The water droplets flowing into the heating chamber 6 evaporate by heating the lower heater 13 when the heater is heated, and can humidify the inside of the heating chamber 6 when the heater is heated. Thereby, the oven cooking menu (cake, bread, etc.) can be slightly humidified, and the finish becomes mild.

[0034]

According to the present invention , since the microwave oven of the present invention is constructed as described above, according to the present invention , since there is no exhaust port to be exhausted to the outside, the heat efficiency at the time of heating the heater is good and the rise of heating is fast. In addition, the maximum settable temperature can be increased.
Since there is no oily smoke or flame outside the microwave oven, it is clean and excellent in safety. Further, since there is no exhaust port for exhausting air in the heating chamber outside the microwave oven, it is possible to prevent radio waves from leaking from the heating chamber to the outside. And the duct
It can be humidified by utilizing the moisture condensed inside.

According to the third aspect of the present invention, since the circulation fan is operated by the humidity in the heating chamber, when the humidity is high, it can be reliably guided to the duct and dehumidified.

According to the fourth aspect , smoke, odor and the like generated in the heating chamber can be removed. According to the fifth aspect , the heat exchanger facilitates removal of water vapor.

According to the sixth aspect , the distance between the ducts can be increased, and the air sucked into the ducts can be sufficiently cooled .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing Embodiment 1 of a microwave oven according to the present invention.

FIG. 2 is a transverse sectional view showing Embodiment 1 of the microwave oven of the present invention.

FIG. 3 is a longitudinal sectional view showing Embodiment 2 of the microwave oven of the present invention.

FIG. 4 is a transverse sectional view showing Embodiment 2 of the microwave oven of the present invention.

FIG. 5 is a longitudinal sectional view showing circulation of air when the heater of FIG. 3 is heated.

FIG. 6 is a transverse sectional view showing Embodiment 3 of the microwave oven of the present invention.

FIG. 7 is a block diagram of a microwave oven according to the present invention.

FIG. 8 is a humidity characteristic diagram of a humidity sensor used in the present invention.

FIG. 9 is a cross-sectional view showing a conventional hot air circulation type microwave oven.

FIG. 10 is a longitudinal sectional view showing a conventional upper and lower heater type microwave oven.

FIG. 11 is an explanatory diagram showing a flow of a flame from a conventional microwave oven.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microwave oven 1a Back surface 2 Exhaust port 3 Inlet port 4 Intake duct 5 Exhaust duct 6 Heating chamber 7 Door 8 Magnetron 9 Cooling fan 10 Convection fan 11 Convection heater 12 Upper heater 13 Lower heater 14 Turntable 15 Oven inlet 16 Oven outlet 18 Deodorizer 19 Humidity sensor 20 Circulation fan 21 Heat exchanger 22 Duct 23 Heated object 24 Operation panel 25 Microcomputer 26 Relay

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F24C 7/02 541 F24C 7/02 350 F24C 1/02 320

Claims (6)

(57) [Claims] 1. A microwave oven having a high-frequency heating means and a heater heating means for heating an object to be heated in a heating chamber, wherein the air contains steam generated from the object to be heated and is taken in from an upper portion of the heating chamber. An intake port, a duct for guiding air taken in from the intake port, a discharge port for discharging air passing through the duct from a lower portion of the heating chamber into the heating chamber, and air sucked from the intake port through the duct. from the discharge port and a circulation fan for circulating the heating chamber, the moisture condensed in the duct, said heater heating means
Microwave characterized that you humidified and supplied into the heating chamber during operation. 2. A high-frequency heating means and a heater heating means.
In a microwave oven for heating an object to be heated in a heating chamber, air containing water vapor generated from the object to be heated is heated.
An intake port for taking in air from above, and
Duct that guides the air, and heats the air that passes through the duct
A discharge port for discharging from the lower part of the chamber into the heating chamber, and
The sucked air passes through the duct from the discharge port to the heating chamber.
A circulation fan that circulates through the duct, and discharges moisture condensed in the duct by natural fall.
It is characterized in that it has a configuration for guiding to the bottom of the heating chamber through the outlet.
Microwave oven to sign . 3. A humidity sensor for detecting humidity in the air taken into the duct, wherein the circulation fan is operated when the humidity detected by the humidity sensor exceeds a predetermined value. The microwave oven according to claim 1 or 2, wherein 4. The method of claim claim 1, characterized in that providing a deodorizing device for deodorizing air was sucked into the said duct
4. The microwave oven according to claim 3. 5. The billing air was sucked into the said duct from claim 1, characterized in that providing a heat exchanger for exchanging heat
Item 5. The microwave oven according to any one of items 4 . 6. The heating chamber according to claim 1, wherein the suction port and the discharge port are disposed substantially diagonally on a side surface of the heating chamber.
The microwave oven according to any one of claims 1 to 5 .