CN105619848B - A kind of microwave heating equipment and method - Google Patents

Abstract

The present invention provides a kind of microwave heating equipment, including microwave generator, microwave cavity and microwave shadow shield part, the microwave generator sends microwave into microwave cavity, it is used to place absorbing material in microwave cavity, the microwave shadow shield part is located in microwave cavity and is used for the outer surface for being covered in absorbing material, the microwave shadow shield part forms by shield microwaves area and through microwave region, described comprising one or more gap the microwave energy in microwave cavity to be entered in absorbing material at gap through microwave region and be absorbed.Heating can be pinpointed and/or oriented to absorbing material using microwave heating equipment provided by the invention.

Description

A microwave heating device and method

technical field

The invention relates to the field of microwaves, in particular to a microwave heating device and method.

Background technique

Microwave has the advantages of selective heating of certain materials, fast heating speed, uniform heating, strong penetration, and small thermal inertia. Applying microwave technology to the field of composite material curing can significantly reduce curing time, reduce production costs, and obtain Excellent product performance, with great development potential.

A lot of research has been carried out in the field of composite material curing at home and abroad, and fruitful results have been obtained. However, these studies have a common feature, the composite materials are all directly exposed to the microwave field to complete the curing. For example, Chinese patent application CN201410295387 provides a method for uniform temperature distribution of microwave-pressure-cured composite materials and a complete set of curing device. The method is to use a polygonal cavity in the pressure vessel body so that microwaves are reflected multiple times in the cavity to improve Uniformity of microwave incidence on composite materials. At the same time, waveguide windows are set at the front and back of the cavity, the gas medium can flow into the cavity, and convective heat exchange occurs with the composite material, which further improves the temperature uniformity of the material, and can realize the gas in the pressure vessel when the composite material is heated and solidified. pressure. The device mainly includes a polygonal cavity and an electromagnetic shielding window. The invention can improve the temperature uniformity of the composite material component and reduce the warping deformation of the microwave solidified composite material component.

When heating a composite material part, because it is a poor conductor of heat, if the traditional heating method is used, the center of the part will heat up slowly and the surrounding area will heat up quickly, but if the traditional microwave method is used for uniform heating, it will be extremely effective. It may lead to slow heat dissipation in the center of the part and overheating, and even if the composite material is heated by microwave and traditional methods at the same time, the heating and curing conditions cannot be well controlled. Therefore, there is a need in the art to develop a special microwave heating device and microwave heating method for this situation.

Contents of the invention

Therefore, the present invention provides a microwave heating device, including a microwave generator, a microwave cavity, a microwave partial shield and a temperature measuring device, the microwave generator sends microwaves into the microwave cavity, and the microwave cavity is used to place microwave-absorbing materials. The microwave partial shield is located in the microwave cavity and is used to cover the outer surface of the absorbing material. The microwave partial shield is composed of a microwave shielding area and a microwave transmission area. The microwave transmission area includes one or more The gap allows the microwave energy in the microwave cavity to enter the microwave absorbing material from the gap and be absorbed by it; the temperature measuring device includes a temperature measuring head and a temperature measuring transmission line, and the temperature measuring head is arranged on the microwave absorbing material inside the microwave partial shield. In the material, one end of the temperature measurement transmission line is connected to the temperature measurement head, and the other end is led out to the outside of the microwave cavity.

In the scheme of the present invention, before the heating performance of the microwave-absorbing material and the performance of the microwave heating device (microwave partial shield) of the present invention are familiar, it is necessary to use the temperature measuring device 4 to research and search for a suitable microwave-absorbing material. heating or curing method. After the R&D personnel have a clear understanding of the above properties, there is no need to install a temperature measuring head in the absorbing material. At this time, the controllable fixed-point heating and curing of the absorbing material can be realized by adjusting the microwave power in time. In the present invention, after the wave-absorbing material (such as a composite material of carbon fiber and resin) is heated and solidified, a small defect will be formed in the product because the temperature measuring head cannot be taken out again. Thereby in the laboratory explores each temperature measuring point and the corresponding relation of microwave heating device in the present invention and forms empirical parameter; The temperature measuring head is set in the material, so as to avoid the formation of small flaws in the product.

The present invention also provides a microwave heating device, which includes a microwave generator, a microwave cavity and a partial microwave shielding member. The microwave generator sends microwaves into the microwave cavity, and the microwave cavity is used to place absorbing materials. The part is located in the microwave cavity and is used to cover the outer surface of the microwave-absorbing material. The microwave partial shielding part is composed of a microwave-shielding area and a microwave-transmitting area. The microwave-transmitting area contains one or more gaps so that the microwave cavity The microwave energy enters the wave-absorbing material from the gap and is absorbed by it; the area of the microwave-penetrating region accounts for 30% or less of the area of the entire microwave partial shielding member.

The present invention also provides a microwave heating device, which includes a microwave generator, a microwave cavity and a partial microwave shielding member. The microwave generator sends microwaves into the microwave cavity, and the microwave cavity is used to place absorbing materials. The part is located in the microwave cavity and is used to cover the outer surface of the microwave-absorbing material. The microwave partial shielding part is composed of a microwave-shielding area and a microwave-transmitting area. The microwave-transmitting area contains one or more gaps so that the microwave cavity The microwave energy enters the microwave-absorbing material from the gap and is absorbed by it; the microwave cavity contains one or more ventilation windows or ventilation walls made of metal honeycomb panels, which are used to shield the microwave while making the microwave cavity Outer airflow is unobstructed. The ventilation window means that a part of the area of the side wall, the bottom plate and the top plate of the microwave cavity is made of metal honeycomb panels. The ventilation wall means that at least one side wall, bottom plate and top plate of the microwave cavity are all made of metal honeycomb panels, for example, the side walls, bottom plate and top plate of the microwave cavity are all made of metal honeycomb panels.

When the microwave-absorbing material in the microwave cavity not only needs fixed-point or directional heating and curing, but also needs to be simultaneously heated and cured by hot pressing as a whole, this device can realize the simultaneous heating or curing effect of microwave fixed-point heating and overall heating of the autoclave.

Therefore, the present invention provides a new microwave heating device and a microwave heating and curing method, so that microwaves can preferentially heat and cure parts of composite material parts, so that the overall heating and curing process is uniform and controllable, thereby obtaining high-performance parts product.

Those skilled in the art know that microwaves usually exhibit three basic characteristics: penetration, reflection and absorption. For glass, some plastics and ceramics, microwaves almost pass through without being absorbed; for absorbing materials such as water and food, they will absorb microwaves and make themselves heat; and for metal substances, they will reflect microwaves. There are microwaves everywhere in nature, but the microwaves that exist in nature cannot be used to heat objects because they are scattered and not concentrated. Microwave ovens use their internal magnetrons to convert electrical energy into microwaves, such as penetrating food at an oscillation frequency of 2450MHZ. When microwaves are absorbed by microwave-absorbing materials, polar molecules (such as water, fat, protein, Sugar, etc.) are attracted to vibrate rapidly at a speed of 2.45 billion times per second. The macroscopic manifestation of this oscillation is that the absorbing material is heated; this is the general principle of microwave heating.

In the present invention, the microwave-absorbing material means that at least one component in the material can absorb microwaves of a certain frequency. Those skilled in the art can understand that in the present invention, microwave energy enters the wave-absorbing material from the gap and is absorbed by the wave-absorbing material at a fixed point. The concept of fixed-point absorption is a macroscopic fixed-point concept, that is, using the When the device heats the absorbing material, it does not only heat a certain point, but heats a designated area.

In a specific implementation manner, the power of the microwave generator is adjustable, preferably its power is linearly adjustable, for example, it is linearly adjustable between 100-600W. The power of the microwave generator can be adjusted within 1500w, for example. In a specific implementation, the power of the microwave generator is more commonly used between 100-600w.

In a specific implementation, the microwave cavity is also provided with a wave-transmitting plate suspended and fixed on the side wall, bottom plate or top plate of the microwave cavity and used to place the absorbing material. The bottom of the component, and the microwave generator is located at the top of the microwave cavity. Such an arrangement makes the microwaves from the microwave generator 1 not directly enter the microwave-absorbing material from the gap, but enter the microwave-absorbing material from the gap after being uniformly dispersed in the microwave cavity; The microwave fixed-point heating method is more stable and controllable; and the microwave generator is placed on the top of the microwave cavity for easy operation.

In a specific embodiment, the microwave frequency is 2450±50 MHz or 915±25 MHz, and the aspect ratio of the slit is ≥2:1, preferably ≥5:1, more preferably ≥10:1. Of course, the microwave frequency can also be 433 MHz or 5800 MHz and other common frequencies used for industrial heating. Preferably, the length of the slit is ≥ 20 mm, preferably ≥ 40 mm, more preferably ≥ 80 mm, and the width of the slit is 1-30 mm. In the present invention, when the microwave frequency is 2450 MHz or 915 MHz, the wavelengths of the two are 12.245 cm and 32.8 cm respectively. In the present invention, the microwave can pass through the gap shorter than the microwave wavelength, but the microwave cannot pass through the hole whose diameter is small to a certain extent, for example, when the hole diameter is below 1/4 of the microwave wavelength, the microwave is difficult to pass through, or After the microwave passes through the hole, the energy is greatly attenuated. In the present invention, when the microwave is transmitted through the slit with a higher aspect ratio, the fixed-point heating effect on the microwave-absorbing material is better.

In the present invention, the slit is rectangular, rhombus, trapezoidal, arc-shaped or special-shaped, which is not limited in the present invention. Preferably, the slit is elongated rectangular, rhombus or trapezoidal. In the present invention, the aspect ratio of the slit refers to the ratio of its length to the narrowest part of the slit. In the present invention, the slits may exist independently, and each slit is separated by the shielded microwave region 31 , or the slits may be connected together in other forms such as holes or gaps, which are not limited in the present invention. In the present invention, the microwave shielding area 31 in the partial microwave shielding member can be in the form of metal plate, metal foil, metal honeycomb hole plate or a combination thereof, such as aluminum plate, aluminum foil or honeycomb aluminum plate. However, it is preferable that the material forming the microwave shielding region in the present invention includes aluminum foil, copper foil or tin foil, and its thickness is more than 0.01 mm.

In the present invention, the temperature measuring device includes one or more of thermocouples, thermistors, infrared sensors, optical fiber fluorescence sensors and optical fiber grating sensors. If the temperature measuring device includes metal wires, microwave shielding treatment needs to be performed on the metal wires. However, if the optical fiber line is used, there is no need to shield the temperature measuring device from microwaves.

In the present invention, the microwave cavity receives the microwaves from the microwave generator and completely shields the microwave energy in the microwave cavity during the working process. The microwave cavity includes an oven door, and the oven door is arranged on a side wall, a bottom plate or a top plate of the microwave cavity, which are not limited in the present invention.

In a specific embodiment, a temperature measuring head is arranged at a fixed-point absorbing place in the wave-absorbing material, and the distance between the temperature measuring head and the gap on the partial microwave shielding member is ≥ 2mm.

In a specific embodiment, the microwave absorbing material is a composite material including carbon fiber and resin, and a gas generated during microwave heating of the microwave absorbing material is also provided on the outside of the microwave partial shield. The vacuum bag extracted in time is preferably also provided with an air felt on the inner side of the vacuum bag and the outer side of the microwave partial shield for the diversion of gas during vacuuming; the temperature measuring device also includes a display screen, which is arranged on the microwave The outside of the cavity is used to display the temperature measured by the temperature measuring head in time. In a specific embodiment, the power of the microwave generator is manually controlled according to the measured temperature instantly displayed on the display screen, so that the heating of the microwave-absorbing material can meet the required requirements.

In a specific implementation manner, the area of the microwave-permeable region 32 accounts for less than 15% of the area of the entire partial microwave shielding member, more preferably less than 5%.

In a specific implementation manner, the structure of at least partially shielding the microwave region in the partial microwave shielding member is pasted and covered on the outer surface of the microwave absorbing material.

The present invention also provides a microwave heating method, including using the above-mentioned microwave heating device to conduct fixed-point and or directional heating on the microwave-absorbing material.

The present invention can bring the following beneficial effects: the present invention utilizes the characteristics that microwaves have material selective heating, can heat absorbing materials rapidly and evenly, and have small thermal inertia and are easy to control. treatment, so that the microwave can only perform directional heating and curing on the area that needs to be heated on the material. The present invention provides a solution and idea for the requirement of local heating or local curing of microwave-absorbing material parts. The invention shortens the heating time of the composite wave-absorbing material and reduces energy consumption.

Description of drawings

Fig. 1 is a schematic diagram of a microwave heating device provided by the present invention,

Figure 2 is a schematic diagram of another microwave heating device provided by the present invention,

Fig. 3 is a schematic diagram of another microwave heating device provided by the present invention,

Fig. 4 is a schematic diagram of another microwave heating device provided by the present invention;

Among them, 1. Microwave generator, 2. Microwave cavity, 3. Partial microwave shielding member, 31. Shielding microwave area, 32. Through microwave area, 4. Temperature measuring device, 41. Temperature measuring head, 42. Display screen, 43. Temperature measurement transmission line, 5. Vacuum bag, 6. Breathable felt, 7. Wave-permeable plate, 8. Vacuum tube, 9. Quick connector, 10. Sealing tape, 01. Wave-absorbing material.

detailed description

Figure 1 provides a microwave heating device, including a microwave generator 1, a microwave cavity 2, a microwave partial shield 3 and a temperature measuring device 4, the microwave generator sends microwaves into the microwave cavity, and the microwave cavity is used to place absorbing Wave material 01, the microwave partial shield is located in the microwave cavity and is used to cover the outer surface of the microwave absorbing material, the microwave partial shield is composed of a microwave shielding area and a microwave transmission area, and the microwave transmission area includes One or more slits allow the microwave energy in the microwave cavity to enter the microwave-absorbing material from the slit and be absorbed by it; the temperature measuring device includes a temperature measuring head 41 and a temperature measuring transmission line 43, and the temperature measuring head is arranged on the microwave part In the microwave-absorbing material inside the shielding member, one end of the temperature measurement transmission line is connected to the temperature measurement head, and the other end is led out to the outside of the microwave cavity. In this example, the microwave cavity is a closed microwave cavity without ventilation windows.

The absorbing material in Figures 1 and 2 is a composite material made of carbon fiber and resin. The preparation method of the composite material is, for example, weaving carbon fiber into a fabric, and then soaking the absorbing material resin into the In the carbon fiber fabric, an uncured composite part is formed which can be contained using a mold made of a wave-transparent material such as glass. The product includes a base at the bottom and two L-shaped pieces at the top, and an approximately triangular slit is formed at the junction of the bottoms of the two L-shaped pieces, so a pre-rolled strip (filler) is used to fill into the slit to eventually fill the area so that the final product is free of cracks. There will be problems in this slit area regardless of the traditional heating method or the ordinary microwave heating method. The traditional heating method makes the heating rate of the center of the workpiece slower than that of the outer part, while the traditional microwave method has difficulty in dissipating heat from the center, and the two Both are difficult to realize fixed-point control of heating. Adopt device and method provided by the present invention to carry out fixed-point heating to this place, for example the slit length and the width on the partial microwave shielding part are respectively 70mm and 2mm, the total height of the wave-absorbing material parts is 40cm, and the thickness of the bottom plate is 5mm, measure The temperature head is set on the bottom plate, and the gap on the microwave partial shield is set directly below the slit, so the minimum distance between the temperature measuring head and the gap on the microwave partial shield is 2mm. When the microwave heating device of the present invention is turned on, microwaves from the microwave generator 1 are input into the microwave cavity 2, and the microwave energy is evenly distributed in the microwave cavity 2. Most of the outer surface of the microwave-absorbing material is shielded and reflected by the microwave partial shield 3, so microwave energy can only enter the microwave-absorbing material inside the microwave partial shield from the slit, because the microwave energy is limited, so it is absorbed The microwave energy is almost completely absorbed by the microwave-absorbing material at a certain place, and the fixed-point wave-absorbing place is, for example, the circular area shown in FIGS. 1 and 2 . Microwave heating has the characteristics of small thermal inertia, so the controllability of fixed-point or directional heating of microwave-absorbing materials is extremely high. In the present invention, because the microwave power generated by the microwave generator is not high, for example, the control power is below 600w, and thus the situation that the metal shield reflects microwaves and sparks does not occur. In common cases, the power of the microwave is continuously adjustable within 600w, for example, within 500w, and in more cases, the power of the microwave is 150-600w. The temperature measuring device includes a temperature measuring head set at a fixed-point absorbing place in the wave-absorbing material, which is used in conjunction with the display to display the temperature change of the fixed-point heating place in time. If the heating degree exceeds expectations, it can be Adjust the heating speed of the workpiece by adjusting the microwave power in real time.

Figure 2 provides a more specific microwave heating device, which also includes a wave-transmitting plate 7, the wave-transmitting plate is arranged in the microwave cavity 2, specifically suspended and fixed on the side wall of the microwave cavity, for placing the microwave absorbing material; the slit is opened at the bottom of the microwave partial shield, and the microwave generator is located on the top wall of the microwave cavity; the device also includes a device for extracting the gas generated during the microwave heating of the absorbing material in time The vacuum bag 5, and the inside of the vacuum bag and the outside of the partial microwave shield are also provided with an air felt 6 for guiding the gas when vacuuming; the temperature measuring device also includes a display screen 42, which is arranged on The outside of the microwave cavity is used to display the temperature measured by the temperature measuring head in time. The components that cooperate with the vacuum bag 5 also include a vacuum tube 8 and a quick connector 9 for vacuuming, and a sealing tape 10 for pasting the vacuum bag on the wave-transmitting plate 7 .

Another microwave heating device is provided in Fig. 3. The microwave-transmitting area 32 in the device includes three slits, which are distributed on the upper and lower sides of the absorbing material, and the three slits are separated by a microwave-shielding area 31. Or three slits can be connected. It has been found that this solution is the same as the one slit solution shown in Fig. 1, and both can exert a fixed-point or directional heating effect on the wave-absorbing material. In addition, there are ventilation windows on the surrounding side walls of the microwave cavity in Fig. 3, and the ventilation windows of the honeycomb metal plate ensure that the microwave is shielded in the microwave cavity and at the same time, the microwave cavity can be well ventilated with the outside.

Another microwave heating device is provided in Fig. 4, which does not involve a temperature measuring device, so it is suitable for industrial large-scale processing (including heating and curing) of microwave absorbing materials after the process parameters are clearly studied.

In the schemes of Figures 1 to 4, the circular dotted line area is the microwave directional heating and curing area, and other areas on the absorbing material except the circular dotted line area are all areas that do not need to be heated or cured in this step. When the fixed-point heating area is heated, the temperature of other areas does not rise significantly or its temperature rises slowly.

In the present invention, the shielded microwave region of the microwave partial shield means that it can at least reflect microwaves of some frequencies, and the microwave-absorbing material means that it can absorb microwaves of At least some frequencies of microwaves are permeable.

As shown in Figures 1 to 4, the present invention provides a device and method for heating a wave-absorbing material with microwaves to raise or solidify the local temperature of a wave-absorbing material. The method is to cover the area of the microwave-absorbing material part that does not need to be heated or cured with microwave shielding material first, and the area of the wave-absorbing material part that needs to be heated or cured is not covered with the microwave shielding material (leaving one or more gaps). ), so that the microwave partial shield 3 is composed of a microwave-shielding region 31 and a microwave-transmitting region 32. Then, the microwave-absorbing material product pasted with the microwave shielding material is placed in the microwave cavity. The microwave generator generates microwaves to enter and evenly disperse in the microwave cavity, and heat or solidify the area of the microwave-absorbing material product without the microwave shielding material (through the microwave area 32 ). The area (shielded microwave area 31 ) pasted with microwave shielding material on the absorbing material product cannot absorb microwave energy because microwaves cannot enter it, and it can basically keep the original temperature substantially unchanged. Therefore, the device and method provided by the present invention can be used to carry out targeted heating or curing on some specific areas on the absorbing material that need to be heated.

In the present invention, the microwave shielding material is covered on the outer surface of the wave-absorbing material, and then the area to be heated or solidified is not covered with the microwave shielding material. When the microwave source is turned on, the microwave cavity is filled with a microwave energy field, and the microwave enters the microwave-absorbing material part from the microwave fixed-point irradiation area in Figures 1 to 3, and heats up or solidifies the area of the microwave-absorbing material part that needs to be heated. At the same time, the operator can know the temperature of the microwave fixed-point irradiation area in the microwave-absorbing material part in real time through the temperature measuring head 41, the temperature measurement transmission line 43 and the display screen 42 placed in the microwave-absorbing material part. Manually adjust the input power of the microwave generator to adjust the temperature of the microwave-irradiated area of the absorbing material; prevent the temperature from being too high or too low.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (17)

1. a kind of microwave heating equipment, including microwave generator (1), microwave cavity (2), microwave shadow shield part (3) and thermometric dress Put (4), the microwave generator sends microwave into microwave cavity, is used to place absorbing material (01), the microwave in microwave cavity Shadow shield part is located in microwave cavity and is used for the outer surface for being covered in absorbing material, and the microwave shadow shield part (3) is by shielding Cover microwave region (31) and formed through microwave region (32), it is described to cause microwave comprising one or more gap through microwave region (32) The microwave energy of intracavitary enters in absorbing material and is absorbed at gap；The temperature measuring equipment includes temperature measuring head (41) and thermometric Transmission line (43), the temperature measuring head are arranged in the absorbing material on the inside of microwave shadow shield part, described thermometric transmission line one end It is connected with temperature measuring head, the other end is led on the outside of the microwave cavity.

2. a kind of microwave heating equipment, including microwave generator (1), microwave cavity (2) and microwave shadow shield part (3), described micro- Wave producer sends microwave into microwave cavity, is used to place absorbing material (01), the microwave shadow shield part position in microwave cavity In in microwave cavity and for being covered in the outer surface of absorbing material, the microwave shadow shield part (3) is by shield microwaves area (31) Formed with through microwave region (32), the microwave energy caused through microwave region (32) comprising one or more gap in microwave cavity Enter at gap in absorbing material and be absorbed；The area through microwave region (32) accounts for whole microwave shadow shield part 30% or less of area.

3. a kind of microwave heating equipment, including microwave generator (1), microwave cavity (2) and microwave shadow shield part (3), described micro- Wave producer sends microwave into microwave cavity, is used to place absorbing material (01), the microwave shadow shield part position in microwave cavity In in microwave cavity and for being covered in the outer surface of absorbing material, the microwave shadow shield part (3) is by shield microwaves area (31) Formed with through microwave region (32), the microwave energy caused through microwave region (32) comprising one or more gap in microwave cavity Enter at gap in absorbing material and be absorbed；It is made up of on the microwave cavity containing one or more metal honeycomb plate Vent window or ventilation wall, for may be such that sidewind is unimpeded inside and outside microwave cavity while shield microwaves.

4. the microwave heating equipment according to any one in claims 1 to 3, it is characterised in that the microwave generator Power adjustable section.

5. microwave heating equipment according to claim 4, it is characterised in that the power linear of the microwave generator can Adjust.

6. the microwave heating equipment according to any one in claims 1 to 3, it is characterised in that also set up in microwave cavity There is the wave transparent plate (7) being suspended vacantly in the side wall, bottom plate or top plate of microwave cavity and for placing absorbing material, the gap is opened In the bottom of the microwave shadow shield part, and microwave generator is located at the top of microwave cavity.

7. the microwave heating equipment according to any one in claims 1 to 3, it is characterised in that microwave frequency 2450 ± 50 megahertzs or 915 ± 25 megahertzs, and the length-width ratio in the gap is >=2：1.

8. microwave heating equipment according to claim 7, it is characterised in that the length-width ratio in the gap is >=5：1.

9. microwave heating equipment according to claim 8, it is characterised in that the length-width ratio in the gap is >=10：1.

10. microwave heating equipment according to claim 7, it is characterised in that the length in the gap is >=20mm, and is stitched The width of gap is 1~30mm.

11. microwave heating equipment according to claim 10, it is characterised in that the length in the gap is >=40mm.

12. microwave heating equipment according to claim 11, it is characterised in that the length in the gap is >=80mm.

13. microwave heating equipment according to claim 1, it is characterised in that the absorbing material be include carbon fiber with The composite of resin, and be additionally provided with the outside of the microwave shadow shield part for microwave to be heated into the absorbing material During the vacuum bag (5) extracted out in time of caused gas；The temperature measuring equipment also includes display screen (42), and it is arranged on microwave It is used to show the temperature that the temperature measuring head measures in time on the outside of chamber.

14. microwave heating equipment according to claim 13, it is characterised in that in the inner side of the vacuum bag and microwave The water conservancy diversion that airfelt (6) is used for gas when vacuumizing is additionally provided with the outside of shadow shield part, in the microwave shadow shield part The structure at least part shield microwaves area, which is pasted, to be covered on the outer surface of the absorbing material.

15. the microwave heating equipment according to any one in claims 1 to 3, it is characterised in that described to pass through microwave region (32) area accounts for less than the 15% of whole microwave shadow shield part area.

16. microwave heating equipment according to claim 15, it is characterised in that the area through microwave region (32) accounts for Less than the 5% of whole microwave shadow shield part area.

17. a kind of microwave heating method, including the use of as described in any one in claim 1~16 microwave heating equipment to inhaling Wave material is pinpointed and/or oriented heating.