JP4036052B2 - Microwave heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microwave heating apparatus that heats an object to be heated such as food by microwaves, and in particular, aims to improve the heating distribution by optimizing the direction of microwaves radiated from a waveguide with openings. Is.
[0002]
[Prior art]
As a conventional microwave heating apparatus of this type, for example, there is one described in Japanese Patent Laid-Open No. 2000-164341. First, FIG. 9 is a sectional configuration diagram of a conventional microwave heating apparatus, FIG. 10 is a perspective view thereof, and FIGS. 11 and 12 are sectional views taken along the line PP ′ of FIG.
[0003]
The microwave radiated from the magnetron 1 which is a typical radiating means is guided into the heating chamber 3 by the waveguide 2 and heats the object to be heated 4 placed in the heating chamber 3. At this time, the coupling portion between the waveguide 2 and the heating chamber 3 has an opening 5 formed by hollowing out the wall surface of the heating chamber 3, and the opening 5 serves as a microwave radiation port. It is. The waveguide 2 is configured in a box shape having a cross section of a × b by a wide H surface 6 and a narrow E surface 7, and transmits microwaves in the direction of arrow 9 from the output antenna 8 of the magnetron 1. is there. Therefore, the direction of arrow 9 will be referred to as the microwave transmission direction. The cross section (shaded portion 10) of the waveguide 2 is the axis of symmetry of the waveguide 2 and will be referred to as the tube axis.
[0004]
As the shape of the waveguide 2, generally, when the wavelength of the microwave is λ, the distance a of the H surface (the width of the waveguide 2) is in the range of λ / 2 <a <λ, and the E surface. By selecting the distance b (thickness of the waveguide 2) as b <λ / 2, the TE10 mode is excited. More specifically, for example, when the microwave heating apparatus is a microwave oven, λ≈122 mm, a = 80 to 90 mm, and b = 15 to 40 mm are almost always selected.
[0005]
In the case of FIG. 11, the opening 5 has a width dimension equal to the waveguide width a and is arranged symmetrically with respect to the tube axis 10, so the directivity in the left-right direction in FIG. 11 is also symmetric. In the case of FIG. 12, the openings 5, 11 a, and 11 b are provided. However, since they are arranged symmetrically with respect to the tube axis 10, the directivity in the left-right direction in FIG. 12 is also symmetric.
[0006]
Japanese Patent Laid-Open No. 8-124670 discloses a configuration as shown in FIG. 13, but the openings 12a and 12b are arranged symmetrically with respect to the tube axis 10, so that the horizontal direction in FIG. The directivity of is also symmetric.
[0007]
These conventional microwave heating devices have a configuration that considers how to uniformly radiate microwaves from the opening in order to prevent uneven heating, and have a symmetrical shape with respect to the tube axis. Was a very natural way of thinking.
[0008]
[Problems to be solved by the invention]
However, the conventional configuration is nothing but that the heating chamber can be heated uniformly when the tube axis coincides with the center line of the wall surface of the heating chamber. For example, when the heating chamber is a rectangular parallelepiped, the wall surface is rectangular, so there are two center lines that form the axis of symmetry. If the tube axis of the waveguide can coincide with either of these, microwaves can be radiated symmetrically to the heating chamber through openings symmetrical to the tube axis, and the distribution is uniform. Can be expected.
[0009]
However, there are cases where such a configuration is not possible. In recent microwave ovens, those having an oven function are the mainstream. For this reason, for example, as shown in FIG. 14, a case where the tube heater 13 crosses the center of the top surface is assumed. This figure is a view of the microwave oven as viewed from above. At this time, if the waveguide 2 is arranged in parallel to avoid the tube heater 13, the tube axis 10 is aligned with the center line 14 of the top surface of the heating chamber 3. , 15 cannot be matched. If an opening as shown in FIGS. 11 to 13 is employed in this configuration, microwaves are radiated symmetrically with respect to the tube axis 10, so that the electric field strength behind the heating chamber (upper in FIG. 14) is strong. The electric field strength in the front (lower side in FIG. 14) becomes weak, and as a result, heating unevenness is likely to occur such that the object to be heated is hot and the object is cold.
[0010]
The present invention solves the above-described conventional problems. When the tube axis of the waveguide and the center line of the heating chamber wall surface do not coincide with each other, the invention has a directivity that is asymmetric with respect to the tube axis by devising the opening configuration. The object is to cause wave radiation and, as a result, to uniform the heating distribution in the heating chamber.
[0011]
[Means for Solving the Problems]
In order to solve the conventional problem, the microwave heating apparatus of the present invention includes a radiating means for radiating microwaves, A waveguide that couples the radiating means to the heating chamber via an opening, and the opening is a position that is off the center of the wall surface that forms the heating chamber and is the target axis of the waveguide Seen from the tube axis Of the waveguide one side At the center of the wall To do.
[0012]
This makes it possible to generate highly directional microwave radiation toward the side with the opening relative to the tube axis, and the heating distribution is uniform when the tube axis of the waveguide does not coincide with the center line of the heating chamber wall surface. Can be
[0013]
DETAILED DESCRIPTION OF THE INVENTION
First The microwave heating apparatus of the invention includes radiation means for radiating microwaves, and a waveguide for coupling the radiation means to a heating chamber, and an opening is formed only on one side when viewed from the tube axis of the waveguide. It is a thing.
[0014]
Since the opening is configured only on one side when viewed from the tube axis of the waveguide, the directivity of the microwave radiated from the opening into the heating chamber is strengthened toward the side where the opening is located. be able to.
[0015]
Also Second The microwave heating device of the invention is configured such that the opening is positioned on the center side of the wall surface of the heating chamber as viewed from the tube axis of the waveguide.
[0016]
Since the opening is positioned on the center side of the top surface of the heating chamber when viewed from the tube axis, the directivity of the microwave toward the center side of the heating chamber is enhanced. Therefore, it is possible to realize a symmetrical microwave distribution based on the center of the heating chamber, where the center of the heating chamber is strong and weakens as it moves away from the center, resulting in uniform heating distribution of the object to be heated. can do.
[0017]
Also Third The microwave heating apparatus of the invention has a configuration in which both the opening and the heating chamber wall surface are substantially rectangular, and one of the two center lines of the rectangular shape is parallel and the other center line coincides. It is a thing.
[0018]
In this case, the opening and the wall surface of the heating chamber are parallel to each other, and the microwaves pass along the matching center line from the intersection of the two center lines of the opening toward the intersection of the two center lines of the wall of the heating chamber. The directivity can be increased, and both sides of the coincident center line can be symmetrical. Therefore, it is possible to easily realize a symmetrical microwave distribution based on the center of the heating chamber so that the center of the heating chamber is strong and weakens as the distance from the center increases. It can be made uniform.
[0019]
Also 4th The microwave heating device of the invention is configured such that the opening is formed in the H plane by coupling to the heating chamber at the H plane of the waveguide.
[0020]
Since the opening is formed in the H plane of the waveguide, an electric field that easily sandwiches the opening can be generated using the electric field generated between the H planes, and the direction matches the direction of the electric field. It is possible to generate a desired electric field intensity distribution in the heating chamber such that the direction of propagation is the propagation direction. Therefore, the electric field strength distribution can be easily controlled.
[0021]
Also 5th In the microwave heating apparatus of the present invention, the opening is shaped to be longer in the microwave transmission direction than in the width direction of the waveguide.
[0022]
Since the opening has a dimension L in the microwave transmission direction that is longer than the dimension W in the width direction of the waveguide, the electric field near the opening in the waveguide is wider than the electric field across the opening in the transmission direction. It is possible to generate a desired electric field strength distribution in the heating chamber such that the electric field across the opening is likely to occur, and the propagation direction is a direction that coincides with the direction of the electric field. Therefore, the electric field strength distribution can be easily controlled.
[0023]
Also 6th The microwave heating device of the invention has a straight heating element, and the heating element and the waveguide are arranged on the same wall so that the longitudinal direction of the heating element and the microwave transmission direction are substantially parallel. The opening is formed only on the heating element side when viewed from the tube axis of the waveguide.
[0024]
Since the opening is configured only on the heating element side as viewed from the tube axis, microwave radiation with strong directivity can be generated on the heating element side. When there is only one heating element, the radiation heating distribution by the heating element is uniform. In In order to do this, it is assumed that the user wants to place it as centrally as possible in the heating chamber. With the configuration of the present invention, the heating element is arranged near the center of the heating chamber, and the microwave radiation can also be directed to the heating element side, that is, the center of the heating chamber, so that heating by the heating element and heating by the microwave are made uniform. be able to.
[0025]
Also 7th The microwave heating apparatus according to the present invention is configured such that a straight squeezed part is formed on a wall surface, and the squeezed part and the waveguide are arranged on the same wall so that the longitudinal direction of the squeezed part and the microwave transmission direction are substantially parallel to each other. The opening is formed only on the side of the narrowed portion when viewed from the tube axis of the waveguide.
[0026]
By configuring the opening only on the narrowed portion side when viewed from the tube axis, microwave radiation with strong directivity can be generated on the narrowed portion side. Therefore, even when the placement of the waveguide is limited due to the presence of the squeezed part, strong microwave radiation toward the squeezed part side is possible, and the object to be heated is made uniform without being affected by the presence or absence of the squeezed part. Can be heated.
[0027]
Also 8th When the microwave heating device of the present invention has a component that obstructs the waveguide arrangement at the center of the wall surface, the E surface of the waveguide is arranged opposite to the component side, and the opening is a tube of the waveguide. It is configured to be positioned on the component side when viewed from the shaft.
[0028]
By configuring the opening only on the component side when viewed from the tube axis, microwave radiation with strong directivity can be generated on the component side. Therefore, even if the placement of the waveguide is limited due to the presence of components, strong microwave radiation toward the component side is possible, and the object to be heated is uniformly heated without being affected by the presence or absence of the component. Can do.
[0029]
Also 9th The microwave heating device of the invention has a placement net for placing an object to be heated in a heating chamber, and the mesh of the placement net is configured substantially parallel to the opening.
[0030]
When the mesh of the placement net is arranged in parallel with the opening, the width direction of the opening Nikka An electric field in such a direction is easily applied to the width direction of the mesh as it is, and the electric field is sequentially transmitted between the meshes and propagates on the placement network, so that it is easy to obtain a uniform electric field distribution along the placement network.
[0031]
further 10th The microwave heating device of the invention has stirring means for stirring the microwave in the vicinity of the opening.
[0032]
By stirring the microwave with the stirring means, it is possible to prevent the standing wave from being generated due to the resonance of the microwave in the heating chamber, and to make the heating uneven by the standing wave more uniform.
[0033]
By the above, microwave radiation with strong directivity to the side with the opening with respect to the tube axis can be generated, and the heating distribution is uniform when the tube axis of the waveguide does not coincide with the center line of the heating chamber wall surface. Can be
[0034]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0035]
Example 1
1 and 2 are configuration diagrams of a microwave heating apparatus according to Embodiment 1 of the present invention. FIG. 1 is a view seen from above, and FIG. 2 is a view seen from the right of a cross section taken along the second center line 15 of the heating chamber of FIG.
[0036]
The microwave radiated from the magnetron 1 as a typical radiating means is guided into the heating chamber 3 by the waveguide 2 and heats the object to be heated 4 placed in the heating chamber 3. At this time, the coupling portion between the waveguide 2 and the heating chamber 3 has an opening 5, and the opening 5 serves as a microwave emission port. The waveguide 2 is formed in a box shape having a cross section of a × b by a wide H surface 6 and a narrow E surface 7. Since the waveguide 2 is coupled to the heating chamber on the H surface 6 side, the opening 5 is also formed. This is a configuration existing on the H surface 6 side. As shown in FIG. 1, the transmission direction of the microwave is such that the tube shaft 10 is transmitted leftward from the output antenna 8 of the magnetron 1. At this time, when wavelengths λ = 122 mm, a = 80 mm, and b = 15 to 40 mm in the free space of the microwave are selected, assuming that the wavelength in the transmission direction (in-tube wavelength) in the waveguide is λg, λg = λ / (1- (λ / (2a)) ^ 2) ^ 0.5≈189 mm. The top surface of the heating chamber 3 has a straight heating element 13 typified by a tube heater such as a miraclon heater, and is used for oven cooking and toaster cooking such as scorching the object 4 to be heated. . At this time, in order to avoid the heating element 13, the waveguide 2 has to be arranged behind the heating chamber (upper side in FIG. 1, right side in FIG. 2), and the opening is similarly arranged. Reference numeral 16 denotes a squeezed portion on the top surface of the heating chamber, and the opening 5 is formed in a flat portion on the upper surface of the squeezed portion 16.
[0037]
At this time, as is clear from FIG. 1, the opening 5 has an elongated rectangular shape with a length L and a width W (narrow in the width direction of the waveguide 2 and long in the transmission direction). The two center lines 17 and 15 have the following relationship with the two center lines 14 and 15 that form the symmetry axis of the substantially rectangular heating chamber top surface. That is, the same as the first center line Master (14 and 17) are parallel and the same as the second center line Master (Both are 15). In this configuration, when the intersection 18 of the center lines 14 and 15 is considered as the center of the top surface of the heating chamber 3, the opening 5 is positioned on the center 18 side of the heating chamber as viewed from the tube axis 10.
[0038]
In the present embodiment, L = 120 mm and W = 20 mm are selected as the shape of the opening 5. The door 19 is a door that can be freely opened and closed in front of the heating chamber 3, and the placement net 20 is for placing the article to be heated 4. FIG. 3 shows the placement net 20 as viewed from above. The mesh of the placement net is formed by a number of elongated slits 21, and the slit 21 and the opening 5 are oriented in parallel. It is configured. Also, in FIG. 2, an antenna 22 as an agitating means is arranged inside the squeezing portion 16, and the antenna shaft 23 is rotated to change the direction of the antenna 22 with time and to achieve uniformity by agitating the microwave. Yes.
[0039]
Subsequently, the operation of the opening 5 will be supplemented using simulation results. 4 and 5 show the simulation results of the electric field strength by the shape of the opening, FIG. 4 shows the case of the conventional opening 24, and FIG. 5 shows the case of the opening 5 of the present embodiment. 4A and 5B, (a) shows the electric field intensity 20 mm below the opening, and (b) shows the electric field intensity 80 mm below the opening, and the lines in the figure are equal electric field intensity lines. 4 and 5, the equal electric field strength lines are coarser in (b) than in (a), so that the electric field strength is weak, that is, the electric field strength is weakened when moving away from the opening. Recognize.
[0040]
First, in the case of the conventional opening 24 shown in FIG. 4, with respect to the microwave transmitted from the right side along the tube axis 10, the opening is symmetrical with respect to the tube axis 10. Intensity distribution. In general, since an electric field stands between the H planes facing each other in the waveguide, the electric field tends to stand from the side c. When the opening 24 is provided on the H plane as in this case, the opening 24 is provided. An electric field in the direction from c to e (or from e to c) is easily generated so as to sandwich the gap. It is known that the TE10 mode usually occurs in the waveguide, the electric field at the center of the waveguide (tube axis 10) is the strongest, and the electric field at the end of the waveguide is zero.
[0041]
Therefore, since the side d and the side f are positions where the electric field is about to be zero, the electric field from c or e cannot be accepted, and an electric field is generated only between c and e. The direction of the electric field makes it easier for the electric field to propagate in the left-right direction in the figure, and the shape of the electric field strength line extends to the left and right.
[0042]
On the other hand, in the case of the present embodiment of FIG. 5, the opening 5 is asymmetric with respect to the tube axis 10 with respect to the microwave transmitted from the right side along the tube axis 10. Electric field strength distribution. In particular, since microwaves are transmitted from the opening 5 to the heating chamber, the electric field strength at the opening 5 is increased.
[0043]
In general, since an electric field stands between the H planes facing each other in the waveguide, when the opening 24 is provided on the H plane as in this case, the electric field tends to rise from the side c ′ and the side d ′. . In the TE10 mode in the waveguide, it is known that the electric field at the center of the waveguide (tube axis 10) is the strongest and the electric field at the end of the waveguide is zero. Since c ′ is closer to the end and d ′ is closer to the center, it is considered that the electric field from d ′ is stronger and dominant. Here, when viewed from d ′, the distance from f ′ is the shortest, and an electric field in the direction from d ′ to f ′ (or from f ′ to d ′) easily occurs. Then, depending on the direction of the electric field, the electric field easily propagates in the vertical direction in the figure, and the shape of the electric field strength line extends vertically. In this case, however, the characteristics vary greatly depending on the opening shape. When the distance between d ′ and f ′ is increased, for example, d ′ extends across the tube axis 10 to the opposite side (upward in the figure), part of c ′ is also present at the center of the waveguide. As a result, the electric field from c ′ also becomes stronger. Further, as the distance between c ′ and e ′ becomes shorter, an electric field from c ′ to e ′ is likely to be generated, and for example, a distribution that averages FIGS. 4 and 5 can be considered.
[0044]
Therefore, in order to take advantage of the effect of the present invention, it is desirable that the opening shape be elongated in the microwave transmission direction rather than the width direction of the waveguide. Specifically, using the in-tube wavelength λg, the length of the opening (L in FIG. 1) is preferably λg / 8 or more and 2λg or less, preferably λg / 4 or more and λg or less. Incidentally, if the length becomes too long, there is a possibility that the waveguide becomes longer and the amount and cost of members increase, and the strength of the heating chamber becomes weak. Particularly in this embodiment, λg = 189 mm and L = 120 mm.
[0045]
On the other hand, the width of the opening (W in FIG. 1) is desirably one side of the waveguide, that is, a / 2 or less. However, in the case of an output of about 1000 kW such as a microwave oven, a spark is avoided even during abnormal use. In view of the safety, it is desirable to set it to 10 mm or more. Particularly, in this embodiment, a = 80 mm and W = 20 mm.
[0046]
FIG. 6 is a characteristic diagram of the present example, and shows a temperature distribution when 200 cc of water is placed in four paper cups as objects to be heated and arranged and heated as shown in the figure. The waveguide 2, the heating chamber 3, and the opening 5 are also shown so that the arrangement can be understood. The numbers in the figure indicate the degree of temperature increase obtained by heating for 70 seconds and taking the difference between the temperature after heating and the temperature before heating. Since it can be considered that the temperature rise is proportional to the power in the water, the power applied to the four paper cups is very close, indicating that the electric field strength distribution is uniform. Considering the distance between the opening and the water in the paper cup, it can be considered that the heating was performed with the electric field intensity distribution of FIG. 5B, but in FIG. Since there seems to be a center of the electric field strength line, this almost coincides with the first center line 14 of the heating chamber as shown in FIG. 6, and it is considered that it was heated extremely uniformly for this reason. Moreover, although it is uniform also in the left-right direction according to FIG. 6, this is also as FIG.
[0047]
Finally, the effect of the microwave heating apparatus of this example will be described.
[0048]
First, since the opening 5 is formed only on one side when viewed from the tube axis 10 of the waveguide, the directivity of the microwave radiated from the opening 5 into the heating chamber 3 exists. The directivity to the side can be strengthened.
[0049]
In particular, since the opening 5 is located on the center 18 side of the top surface of the heating chamber 3 as viewed from the tube axis 10, the directivity of the microwave toward the center 18 side of the heating chamber 3 is increased, and as a result, the heating chamber 3 The heating distribution in can be made uniform.
[0050]
Further, both the opening 5 and the top surface of the heating chamber 3 have a substantially rectangular shape, and of the two center lines, one center lines 14 and 17 are parallel and the other center line 15 coincides. At this time, the directivity of the microwave becomes stronger downward in the vertical direction of the opening 5 in FIGS. 1 and 5 and can be made symmetrical in the left-right direction of the opening 5. That is, it can radiate | emit uniformly with respect to a heating chamber.
[0051]
In addition, since the opening 5 is formed in the H surface 6 of the waveguide 2, an electric field that easily sandwiches the opening 5 can be generated using the electric field generated between the H surfaces. It is possible to generate a desired electric field strength distribution in the heating chamber 3 such that the direction coincident with the direction of the propagation is the propagation direction.
[0052]
Further, since the opening 5 has a dimension L in the microwave transmission direction that is longer than the dimension W in the width direction of the waveguide 2, the electric field in the vicinity of the opening 5 in the waveguide 2 has an opening in the transmission direction. An electric field that crosses the opening in the width direction is more likely to occur than an electric field that crosses the electric field, and a desired electric field strength distribution in the heating chamber 3 can be generated such that the direction corresponding to the direction of the electric field is the propagation direction.
[0053]
Further, since the length L of the opening is λg / 8 or more and 2λg or less, and particularly λg / 4 or more and λg or less, the opening 5 can be easily made long in the microwave transmission direction. In this embodiment, L = 120 mm is shown, but the present invention is not limited to this. When the length is shortened (for example, less than 40 mm), it may be difficult for microwaves to enter the heating chamber 3, and when the length is too long (for example, more than 200 mm), the waveguide becomes long and the amount and cost of members are increased. There is also a possibility that the strength of the heating chamber will be weakened. Particularly in this embodiment, λg = 189 mm and L = 120 mm.
[0054]
Further, the width W of the opening 5 may be selected on one side of the waveguide, that is, a / 2 or less. However, in the case of an output of about 1000 kW such as a microwave oven, it is safe to avoid sparks even during abnormal use. It is desirable to make it 10 mm or more in consideration of the properties. Particularly, in this embodiment, a = 80 mm and W = 20 mm.
[0055]
Further, the straight heating element 13 and the waveguide 2 are arranged on the same wall so as to be substantially parallel, and the opening 5 is configured only on the heating element 13 side when viewed from the tube axis 10. Highly directional microwave radiation is possible. In particular, in the case of a single heating element as shown in FIGS. 1 and 2, it is assumed that it is desired to place the heating element in the center of the heating chamber as much as possible in order to make the radiation heating distribution by the heating element uniform. In this embodiment, the heating element 13 is disposed near the center of the heating chamber, and the microwave radiation can be directed toward the center of the heating chamber, so that heating by the heating element and heating by the microwave can be made uniform.
[0056]
Further, since the slit 21 of the placement net 20 is arranged in parallel with the opening 5, the width direction of the opening 5 Nikka Since the electric field in such a direction is easily applied to the width direction of the slit 21 as it is, and the electric field easily propagates on the placement network 20, a more uniform effect can be expected.
[0057]
Further, since the antenna 22 for stirring the microwave is provided in the vicinity of the opening 5, the generation of the standing wave due to the resonance in the microwave heating chamber 3 is prevented, and the heating unevenness due to the standing wave is suppressed to make it more uniform. be able to.
[0058]
(Example 2)
FIG. 7 is a configuration diagram of the microwave heating apparatus according to the second embodiment of the present invention.
[0059]
A microwave oven, which is a typical microwave heating device, is viewed obliquely from the front, and the side wall of the heating chamber 3 is made of a waveguide 2, a triangular opening 25, and a material that transmits microwaves while blocking the opening ( A cover 26 made of mica or polypropylene), a rail 27 composed of a straight squeezed portion, a turntable 28 on which an object to be heated is placed and rotated. In particular, the method of configuring the rail 27 with a narrowed portion of the wall surface is a configuration that is often used for placing a square dish in the case of a product having an oven function.
[0060]
In the present embodiment, the rail 27 and the waveguide 2 are arranged substantially in parallel, and the opening 25 is configured only on the rail 27 side as viewed from the tube axis 10, so that microwave radiation having strong directivity is provided on the rail side. Can do. Therefore, even when the waveguide 2 can be disposed only above the wall surface due to the rails 27 as shown in FIG. 7, the downward microwave radiation can be realized, so that the object to be heated can be heated uniformly. In particular, in the case where the shape of the object to be heated is flat, if the object to be heated is placed on the turntable 28, the object to be heated is located at a considerably lower position, so that a more remarkable effect can be expected.
[0061]
(Example 3)
FIG. 8 is a configuration diagram of the microwave heating apparatus according to the third embodiment of the present invention.
[0062]
In this embodiment, the opening 28 is L-shaped, and the wall surface shape of the heating chamber 29 is not a rectangular shape but a pentagon. Of course, the present invention is not limited to the rectangular shape of both the opening and the heating chamber. For example, in the case of the present embodiment, the actual heating chamber 29 may be expanded as 30. In this way, the first center line 31 of the heating chamber, the second center line 32 of the heating chamber, and the center 33 of the heating chamber can be determined, and the configuration of the present invention described in Embodiment 1 can be applied. .
[0063]
In the case of the shape of the opening 28 of the present embodiment, the directivity of the microwave radiation tends not only from the top to the bottom of FIG. 8 but also from the right to the left as shown by the arrow 34. It seems to come. Accordingly, in such a case, uniform heating is possible by arranging the waveguide 2 and the opening 28 on the right side of the second center line 32 of the heating chamber.
[0064]
Further, in this embodiment, there is a part 35 that obstructs the waveguide arrangement at the center 33 of the heating chamber, which is, for example, an infrared sensor, a humidity sensor, a punching hole for ventilation, or an interior lamp. Various parts such as a motor for a stirrer can be considered. Of course, even if there is something that is not described here, it may interfere with the waveguide arrangement, and based on the idea of the present invention, by changing the shape of the opening and the waveguide arrangement, Can be emitted uniformly, and the object to be heated can be heated uniformly.
[0065]
【The invention's effect】
As described above, the microwave heating apparatus according to the present invention includes a radiating unit that radiates microwaves, a waveguide that couples the radiating unit to the heating chamber, and a coupling portion between the waveguide and the heating chamber. The opening is configured only on one side when viewed from the tube axis of the waveguide.
[0066]
This makes it possible to generate highly directional microwave radiation toward the side with the opening relative to the tube axis, and the heating distribution is uniform when the tube axis of the waveguide does not coincide with the center line of the heating chamber wall surface. Can be
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a microwave heating apparatus according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional configuration diagram of the microwave heating apparatus according to the first embodiment of the present invention.
FIG. 3 is a configuration diagram of a placement network according to the first embodiment of the present invention.
FIG. 4 is an electric field intensity distribution diagram obtained by simulation with respect to a conventional example for comparison with Example 1 of the present invention.
(A) Electric field intensity distribution diagram 20 mm below the opening
(B) Electric field intensity distribution diagram 80 mm below the opening
FIG. 5 is an electric field intensity distribution diagram obtained by simulation with respect to Example 1 of the present invention.
(A) Electric field intensity distribution diagram 20 mm below the opening
(B) Electric field intensity distribution diagram 80 mm below the opening
FIG. 6 is a temperature distribution diagram of water in a paper cup in Example 1 of the present invention.
FIG. 7 is a configuration diagram of a microwave heating apparatus according to a second embodiment of the present invention.
FIG. 8 is a configuration diagram of a microwave heating apparatus according to Embodiment 3 of the present invention.
FIG. 9 is a configuration diagram of a conventional microwave heating apparatus.
FIG. 10 is a perspective configuration diagram of a magnetron and a waveguide of a conventional microwave heating apparatus.
FIG. 11 is a configuration diagram of an opening of a conventional microwave heating apparatus.
FIG. 12 is a configuration diagram of an opening of a conventional microwave heating apparatus.
FIG. 13 is a configuration diagram of an opening of a conventional microwave heating apparatus.
FIG. 14 is a configuration diagram of a microwave heating apparatus having a heating element.
[Explanation of symbols]
1 Magnetron (radiation means)
2 Waveguide
3, 29 Heating chamber
4 Object to be heated
5, 25, 28 opening
6 H side
7 E side
10 pipe shaft
13 Heating element
14, 31 First center line of heating chamber
15 Second center line of heating chamber, second center line of opening
17 First centerline of opening
18, 33 Center of heating chamber
19 Placement network
21 Slit (mesh)
27 Rail (squeezed part)
32 Second centerline of heating chamber
35 parts

Claims (9)

Radiating means for radiating microwaves, and a waveguide for coupling the radiating means to the heating chamber through an opening , the opening being at a position off the center of the wall surface forming the heating chamber, and A microwave heating apparatus positioned on one side of the waveguide and on the center side of the wall surface as viewed from a tube axis that is a target axis of the waveguide . 2. The micro of claim 1, wherein both the opening and the heating chamber wall surface have a substantially rectangular shape, and one of the two center lines of the rectangular shape is parallel and the other center line coincides. Wave heating device. 2. The microwave heating apparatus according to claim 1 , wherein the opening is formed in the H plane by coupling to the heating chamber at the H plane of the waveguide . The microwave heating apparatus according to claim 1, wherein the opening has a shape that is longer in the microwave transmission direction than in the width direction of the waveguide . 2. A straight heating element at the center of the wall, wherein the heating element and the waveguide are arranged on the same wall so that the longitudinal direction of the heating element and the microwave transmission direction are substantially parallel to each other. The microwave heating apparatus as described. Claims in which a straight constricted portion is formed at the center of the wall surface and on the wall surface, and the constricted portion and the waveguide are arranged on the same wall surface so that the longitudinal direction of the constricted portion and the microwave transmission direction are substantially parallel. Item 2. The microwave heating apparatus according to Item 1. When having a component that obstructs the waveguide arrangement at the center of the wall surface , the E side of the waveguide is arranged opposite to the component side, and the opening is on the component side when viewed from the tube axis of the waveguide. The microwave heating device according to claim 1, wherein the microwave heating device is positioned. The microwave heating apparatus according to claim 1, further comprising a placement net for placing an object to be heated in the heating chamber, wherein the mesh of the placement net is configured substantially parallel to the opening . The microwave heating apparatus according to claim 1, wherein the microwave heating apparatus includes a stirring unit that stirs the microwave in the vicinity of the opening .

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