JP2008258091A - Microwave heating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave heating apparatus which can achieve a uniform heating over an entire heating chamber of a wide width and also a partial and intensive heating. <P>SOLUTION: The microwave heating apparatus is provide with a microwave generating means 32, wave guide 33, heating chamber 34 having a width-wise dimension larger than a depth-wise dimension, unrotatable placing base 35 on which a heating object is placed, housing space 36 for the heating object, rotatable antennas 38, 39 arranged symmetrically up and down and right and left, in a width-wise direction of the heating chamber for discharging microwave in the heating chamber, driving means 40, 41 of the rotatable antennas, and controlling means 411 for controlling the driving means and controlling a direction of the antennas. The controlling means 411 controls a portion having a strong discharging directionality in at least one rotatable antenna to face in a predetermined direction and a specific heating object can be intensively heated. As a result, a uniform heating over an entire heating chamber can be achieved and a partial and intensive heating can be achieved as well. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a microwave heating apparatus that dielectrically heats an object to be heated.

  The microwave oven, which is a typical microwave heating device, can directly heat the food that is a typical object to be heated, making it an indispensable device in daily life with the simplicity that does not require the preparation of a pan or pot. It has become. In the microwave oven, the size of the space for storing food in the heating chamber through which microwaves propagate is approximately 300 to 400 mm in the width direction and the depth direction, and approximately 200 mm in the height direction. In recent years, the bottom of the space for storing foods has been flattened, and the width dimension is set to 400 mm or more, which is relatively larger than the depth dimension. Products that have been put into practical use.

  By the way, the wavelength of the microwave used by the microwave oven is about 120 mm, a strong electric field distribution (hereinafter referred to as radio wave distribution) is generated in the heating chamber, and the influence of the shape of the object to be heated and its physical characteristics It is known that heating unevenness occurs due to synergy. In particular, in the heating chamber having a large dimension in the width direction as described above, it is necessary to further improve the uniformity of heating in order to simultaneously heat foods placed on a plurality of tableware.

  Conventionally, this type of microwave heating apparatus is provided with one radiation antenna and rotationally drives the antenna. However, as a measure for improving the uniformity of heating, this type of microwave heating apparatus is provided with a plurality of radiation antennas or a plurality of high-frequency agitation devices. A device including means has been proposed (see, for example, Patent Document 1).

However, even if the interior is large, it does not always heat a large amount of food.For example, when warming a mug full of milk, it is more efficient to concentrate only on milk without heating the entire interior uniformly. Conceivable. Even when multiple foods are heated at the same time, for example, when there is a difference in the temperature of the food, as in the case of heating frozen food and food at room temperature at the same time, it may be desirable to heat only low-temperature food intensively. is there. In addition, if it's like a box lunch box, it contains foods (pickles, salads, desserts, etc.) that you don't want to heat in one container, and only the foods that should be heated (rice, side dishes, etc.) Sometimes you want to. In such a case, the function which can carry out local concentration heating instead of the whole uniform heating is needed. For this reason, there has been proposed a technique in which a plurality of radiation antennas are switched and central heating is performed by controlling a stop position (for example, see Patent Document 2).
JP 2004-259646 A Japanese Patent No. 3617224

  However, in any of the conventional configurations described above, various devices have been devised, but in a microwave heating apparatus having a heating chamber with a wide width, usually, the entire interior is uniformly heated while depending on the purpose. Realizing local concentrated heating was also difficult as a practical configuration. Especially in the case of a steam oven type where the evaporating dish holding water with a high microwave absorption effect is provided on one side of the heating chamber, it is difficult to achieve both uniform heating and local concentrated heating at a satisfactory level. there were.

The present invention solves the above-described conventional problems, and in a microwave heating apparatus having a heating chamber with a wide width, it is possible to achieve localized central heating while normally achieving uniform heating of the entire interior, and It is an object of the present invention to provide a microwave heating apparatus that can easily switch between uniform heating of the entire interior and local concentrated heating.

  In order to solve the above-described conventional problems, a microwave heating apparatus according to the present invention includes a heating chamber having a width direction dimension larger than a depth direction dimension, microwave generation means for supplying microwaves to the heating chamber, A plurality of rotating antennas that radiate microwaves from the microwave generating means into the heating chamber; a driving means that rotationally drives the rotating antenna; and a control means that controls the direction of the rotating antenna by controlling the driving means; One of the plurality of rotating antennas radiates microwaves from the top of the heating chamber, the remaining rotating antennas are radiated from the bottom of the heating chamber, and the control means includes at least one of A part having strong radiation directivity in the rotating antenna is controlled in a predetermined direction to heat a specific object to be heated in a concentrated manner.

  As a result, the two rotating antennas are arranged vertically and horizontally at symmetrical positions with respect to the width direction of the wide heating chamber, so that at least a left-right symmetric heating distribution is obtained and the microwaves are more than in the case of one rotating antenna. The radiation pattern can be varied, and the heating distribution in the entire chamber can be easily made uniform.

  In addition, if at least one of the rotating antennas is controlled in a predetermined direction with a portion having a strong radiation directivity, microwaves can be radiated strongly in a predetermined direction, so that a specific object to be heated can be easily and intensively heated. can do.

  The microwave heating apparatus of the present invention can realize a microwave heating apparatus that can perform uniform heating and local concentrated heating throughout the entire chamber, and has high safety at the time of switching.

  A first invention is a heating chamber having a width dimension larger than a depth dimension, a microwave generating means for supplying a microwave to the heating chamber, and a microwave from the microwave generating means in the heating chamber. A plurality of rotating antennas that radiate; a driving unit that rotationally drives the rotating antenna; and a control unit that controls the direction of the rotating antenna by controlling the driving unit, wherein one of the plurality of rotating antennas is heated. The microwave is radiated from the top of the chamber and the remaining rotating antennas are radiated from the bottom of the heating chamber, and the control means has at least one portion of the rotating antenna having a strong radiation directivity in a predetermined direction. In this configuration, the specific object to be heated is centrally heated.

  As a result, the two rotating antennas are arranged vertically and horizontally at symmetrical positions with respect to the width direction of the wide heating chamber, so that the heating distribution is at least symmetrical, and the microwave is more than in the case of one rotating antenna. The radiation pattern can be diversified, and the heating distribution in the entire chamber can be easily made uniform. In addition, if at least one of the rotating antennas is controlled in a predetermined direction with a portion having a strong radiation directivity, microwaves can be radiated strongly in a predetermined direction, so that a specific object to be heated can be easily and intensively heated. can do. Furthermore, it is an extremely simple and low-cost configuration that controls the orientation of at least one of the two rotating antennas coupled to a single waveguide. When switching, there is no risk of changing the coupling state of the microwave, and it is safe, and severe dimensional management such as gap management is not so necessary. Therefore, it is possible to realize a very realistic microwave heating apparatus that has a simple configuration, in particular, can be easily switched between uniform heating and local concentrated heating throughout the entire chamber and has high safety during switching.

  According to a second aspect of the present invention, in the first aspect of the invention, the first aspect further includes a steam generating means for supplying steam to the heating chamber, the steam generating means having an evaporating dish provided on one side in the width direction of the heating chamber, The rotating antenna that radiates radio waves from above is provided on the opposite side of the heating chamber from the side on which the evaporating dish is provided.

  As a result, even during cooking using steam and when water with a high microwave absorption rate is present in the evaporating dish, there is an upper rotating antenna on the side away from this, so there is an upper part on this water side. Compared with the case where a rotating antenna is provided, microwaves are more effectively directed to food, and efficient heating is possible.

  In particular, according to a third aspect of the present invention, in the first or second aspect, the setting means, the central heating determination means for determining whether or not to perform central heating based on the setting content by the setting means, and the determination of the central heating determination means Based on the contents, at least one of the rotating antennas is configured to control a specific portion to be heated in a concentrated manner by controlling a portion having a strong radiation directivity in a predetermined direction. Thereby, since the central heating is performed by controlling the rotating antenna based on the set contents, it is possible to easily switch to the central heating while realizing uniform heating of the entire interior with a constant rotation. From the user's point of view, the microwave heating device automatically switches between uniform heating and concentrated heating as long as the setting is made, so that the risk of mistakes can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1-4 has shown the microwave oven as a microwave heating apparatus in Embodiment 1 of this invention.

  A microwave oven 31 in the present embodiment is connected to the magnetron 32, which is a typical microwave generating means, a waveguide 33 that transmits the microwave radiated from the magnetron 32, and a width connected to the top of the waveguide 33. The heating chamber 34 having a direction dimension (about 410 mm) larger than the depth direction dimension (about 315 mm) and a food (not shown), which is a typical object to be heated, are fixedly disposed in the heating chamber 34. A non-rotating mounting table 35 having a property that microwaves can be easily transmitted due to being made of a low-loss dielectric material such as ceramic or glass, and formed substantially above the mounting table 35 in the heating chamber 34 to be heated. A heated object storage space 36 serving as a space in which objects can be stored is provided. Further, an evaporating dish 34a serving as a steam supply means for generating steam and supplying it to the heating chamber is provided near the inner side of the inner part of the heating chamber 34. An antenna space 37a is provided below the pedestal 35, and one rotating antenna 38 is provided. An antenna space 37b is provided above the heating chamber 34 on the opposite side of the evaporating dish, and the other rotating antenna 39 is provided. The microwave in the wave tube 33 is radiated into the heating chamber 34 from the left, right, top and bottom.

  The two rotating antennas 38 and 39 are provided at left and right and up and down symmetrical positions with respect to the width direction of the heating chamber 34, and are rotated by motors 40 and 41 as typical driving means. The motors 40 and 41 are controlled by a control unit 411. The control unit 411 controls a specific portion of at least one rotary antenna 38 or 39 with a strong radiation directivity to a specific direction. The configuration is such that the object to be heated can be centrally heated. The portion facing the upper rotating antenna 39 is formed of the same member as the mounting table 35.

The rotating antennas 38 and 39 include coupling portions 45 and 46 made of a conductive material having a diameter of about 18 mm and a substantially cylindrical shape passing through the substantially circular coupling holes 43 and 44 having a diameter of about 30 mm, and coupling portions 45 and 4.
Radiation portions 47 and 48 made of a conductive material which is electrically connected and integrated with the upper end of 6 by caulking, welding or the like and has a larger area in the horizontal direction than in the vertical direction. Is configured to be fitted to the shafts of the motors 40 and 41 so that the center of the motor is the center of the rotational drive. The radiating portions 47 and 48 are configured to have radiation directivity because the shape is not constant with respect to the direction of rotation (atypical).

  As shown in FIGS. 2 and 3, the waveguide 33 is disposed obliquely on the back surface of the heating chamber, and a magnetron 32 is provided at the center thereof so that the distances from the magnetron 32 to the coupling portions 45 and 46 are equal. Therefore, the microwave radiated from the magnetron 32 is distributed almost uniformly into the heating chamber 34 via the waveguide 33 and the rotating antennas 38 and 39.

  The radiating portions 47 and 48 have the same shape, and the radiating portion upper surfaces 51 and 52 have a substantially quadrilateral R shape, and the radiating portion bending portion 53 bent to the heating chamber bottom surface 42 side on two opposite sides thereof. , 54 and restricts microwave radiation to the outside of the two sides. The distance between the heating chamber upper and lower surfaces 42 and the radiating portion upper surfaces 51 and 52 is about 10 mm, and the radiating portion bent portions 53 and 54 are pulled down to a position lower by about 5 mm. The remaining two sides have different horizontal lengths from the coupling portions 45 and 46 to the end portions, and the length of the end portions 55 and the coupling portions 45 and 46 from the center of the coupling portions 45 and 46 is about 75 mm. An end portion 57 having a length from about 55 mm is formed. Moreover, the dimension of the width direction of each edge part is 80 mm or more. In this configuration, the rotating antennas 38 and 39 can increase the radiation directivity in the direction from the coupling portions 45 and 46 to the end portions 57 and 58.

  In this configuration, when heating a general food uniformly, it is not necessary to pay particular attention to the place of placement as in the case of a conventional microwave oven, and the rotating antennas 38 and 39 may be rotated at a constant speed as in the conventional case. Here, when steam heating is performed simultaneously with microwave heating, even if there is an evaporating dish 34a on one side in the width direction of the heating chamber and water that easily absorbs microwaves is present in this evaporating dish side Since the upper rotating antenna 39 radiating a direct wave toward the upper side is provided on the side opposite to the evaporating dish 34a, the amount of microwave absorbed in the water can be reduced, and the microwave distribution in the width direction of the heating chamber Even if foods are distributed in the left-right direction of the heating chamber, they can be heated uniformly.

  On the other hand, in the case of concentrated heating, as shown in FIG. 4, the mark 59 previously marked on the mounting table 35 is set as a specific position for concentrated heating, and the user places food on the mark 59. The mark 59 is substantially the center in the width direction of the heating chamber 34 and the center in the depth direction, and the end portions 57 and 58 of the rotating antennas 38 and 39 are placed in the heating chamber 34 in order to concentrate and heat the food placed on the mark 59. Control is performed so as to be directed in a predetermined direction, ie, approximately the center in the width direction and approximately the center in the depth direction. When at least one of the end portions 57 and 58 of the rotating antennas 38 and 39 faces the approximate center in the width direction of the heating chamber 34 and the approximate center in the depth direction, the radiation directivity toward the ends 57 and 58 is strong. In particular, microwaves are radiated from the direction of the end portions 57 and 58, and the food placed on the mark 59 located in that direction can be intensively heated. Also in this case, the amount of microwaves absorbed by the water from the upper rotating antenna 39 can be reduced, and the food can be heated by effectively using the microwaves. In the drawing, the rotating antennas provided on the top, bottom, left and right are all indicated by broken lines.

  In order to orient the rotating antennas 38 and 39 in a predetermined direction, a stepping motor is used as the motors 40 and 41, or even if the motor rotates at a constant speed, the energization time is controlled by detecting the reference position. Can be considered.

5 and 6 show the characteristics of uniform heating and concentrated heating of the present embodiment. FIG. 5 shows the result of heating about 150 g of a bowl of rice with the rotating antennas 38 and 39 being rotated at a constant rotation rate of 10 seconds, in particular, being heated from the four hatched portions 60 in the periphery, The hatched portion 61 is heated. Rice is a difficult food that does not easily become uniform unless the heating distribution itself is good due to low convection and heat conduction, but in this case, the heating distribution is balanced in the front, back, left, and right, and is fairly uniform. it is conceivable that.

  On the other hand, FIG. 6 shows the result of placing about 200 cc of milk in a mug on the mark 59 and heating the rotating antennas 38 and 39 with the end portions 57 and 58 stopped toward the center. Portion 62 is strongly heated. In the case of liquids such as drinks, it is known that heating only the bottom tends to be uniform by convection, and conversely, if heat is applied uniformly in the vertical direction, only the top is heated. Therefore, since the distribution of FIG. 6 can heat the bottom part intensively, it is considered that the distribution is suitable for the heating of the drink.

  Next, specific control will be described with reference to FIG. In FIG. 3, the setting means 63 is disposed below the door 64, and based on the content set by the user using the setting means 63, the control means 411 determines whether the central heating determination means 66 performs central heating. Is. Based on the determination result, the control unit 411 is configured to control the magnetron 32 and the motors 40 and 41.

  For example, when the user sets the hot rice with the setting means 63, the central heating determination means 66 determines that the central heating is not required, and the control means 411 causes the motors 40 and 41 to rotate the rotary antennas 38 and 39 at a constant rotation. Control. On the other hand, when the user sets warming of milk by the setting means 63, the central heating determination means 66 determines that central heating is necessary, and the control means 411 drives the motors 40 and 41 to rotate the rotary antennas 38 and 39. Control is performed so that the end portions 57 and 58 of the radiating portions 47 and 48 are stopped when they are directed to the center. As a result, the rice can be heated uniformly throughout, and the milk can be heated intensively at the bottom.

  As described above, in the present embodiment, since the two rotating antennas 38 and 39 are arranged at symmetrical positions in the vertical and horizontal directions with respect to the width direction of the wide heating chamber 34, at least a symmetrical heating distribution and In addition, the microwave radiation pattern can be more diversified than in the case of a single rotating antenna, making it easy to distribute the heating distribution in the entire cabinet even if there is an evaporating dish on the left or right side of the heating chamber. It can be made uniform. Further, if the end portions 57 and 58 that are strong radiation directivity portions of both the rotating antennas 38 and 39 are controlled in a predetermined direction (center direction in the chamber), the microwaves are controlled in a predetermined direction (center in the chamber). (Specific direction) can be radiated strongly, so that it is possible to easily and intensively heat a specific object to be heated (milk placed on the mark 59).

  In this embodiment, an example in which both of the rotating antennas 38 and 39 are stopped has been described. For example, one of the rotating antennas 38 and 39 is stopped and the other is rotated, or the other is stopped halfway and the other is rotated. Various control methods are conceivable, such as changing the one that has been stopped halfway to rotate and stopping the one that has been rotating. Such a control method is effective in the case where it is desirable that the time between concentrated heating and uniform heating is desirable because concentrated heating is too concentrated. At this time, the ratio between rotation and stop may be optimized as appropriate.

  Furthermore, the microwave heating apparatus according to the present embodiment has a very simple configuration in which the directions of the two rotating antennas 38 and 39 coupled to one waveguide 33 are controlled. There is no risk of changing the coupling state of microwaves when switching between local concentrated heating, and there is no need for severe dimensional management such as gap management, so it can be realized with a very realistic configuration. is there.

  In addition, the microwave in the waveguide 33 is drawn out to the heating chamber 34 side from the gap between the coupling holes 43 and 44 and the coupling portions 45 and 46, but the radiation portion 47 integrated with the coupling portions 45 and 46, Since the shape of 48 is not a fixed shape (for example, a circle, a cylinder, a cone, a sphere, etc.) with respect to the direction of rotation, the ease of propagation of microwaves differs depending on the direction. The radiation directivity is such that the radiation directivity is strong in the easy direction and the radiation directivity is weak in the direction difficult to propagate. When the rotating antennas 38 and 39 are rotating at a constant speed, if a microwave with a constant output is radiated for a time sufficiently longer than the rotation period, the microwaves are averaged in the direction of rotation. Are heated at the same level and have a concentric heating distribution (for example, heated strongly in a circle or strongly heated in a donut shape). On the other hand, when the rotation antennas 38 and 39 are stopped or the rotation speed and the output of the microwave are changed to limit the heating mainly in a predetermined direction, the heating distribution is not concentric but is determined by the radiation directivity. The object to be heated (or part of the object to be heated) in the vicinity of the heating distribution, that is, the portion having the strong radiation directivity of the rotating antennas 38 and 39 is easily heated strongly and can be heated intensively.

  As described above, the microwave heating apparatus according to the present invention can be achieved at a level at which uniform heating and local intensive heating of the entire interior can be satisfied, and switching between uniform overheating and local intensive heating is easy and safety at the time of switching. And a very practical microwave heating apparatus can be realized. Therefore, it can be applied to uses such as heating, thawing, ceramics heating, drying, sintering or biochemical reaction of various dielectric materials such as food.

The perspective view when the door of the microwave heating apparatus in Embodiment 1 of this invention is opened Configuration view seen from the front of the microwave heating device Sectional view by the AA line of FIG. Sectional view along line CC (A) Rice heating distribution view from above (b) Rice heating distribution view from side (A) Milk heating distribution viewed from above (b) Milk heating distribution viewed from the side

Explanation of symbols

31 Microwave oven (microwave heating device)
32 Magnetron (microwave generation means)
33 Waveguide 34 Heating chamber 35 Mounting table 36 Heated object storage space 37 Antenna space 38, 39 Rotating antenna 40, 41 Motor (driving means)
411 Control means

Claims (3)

A heating chamber having a width direction dimension larger than a depth direction dimension, microwave generating means for supplying microwaves to the heating chamber, and a plurality of rotating antennas for radiating microwaves from the microwave generating means into the heating chamber And a driving means for rotationally driving the rotating antenna, and a control means for controlling the driving means to control the direction of the rotating antenna, wherein one of the plurality of rotating antennas is microwaved from the upper part of the heating chamber. And the remaining rotating antenna is provided so as to radiate microwaves from the bottom of the heating chamber, and the control means controls a specific portion of at least one of the rotating antennas in a predetermined direction by controlling a portion having a strong radiation directivity. A microwave heating apparatus configured to centrally heat an object to be heated. Steam generating means for supplying steam to the heating chamber is provided, the steam generating means has an evaporating dish provided on one side in the width direction of the heating chamber, and a rotary antenna that radiates radio waves from the upper portion of the heating chamber is used to evaporate the heating chamber. The microwave heating apparatus according to claim 1, wherein the microwave heating apparatus is provided on a side opposite to the side on which the dish is provided. A setting unit, a central heating determination unit that determines whether or not to perform central heating based on the setting content by the setting unit, and a portion having a strong radiation directivity based on the determination content of the central heating determination unit The microwave heating device according to claim 1 or 2, wherein the microwave is heated in a predetermined direction so that a specific object to be heated is concentratedly heated.