Microwave Heating Chamber

Abstract

The present application provides a microwave heating chamber, belonging to the field of microwave heating technology, comprising a metal housing with a through-hole intermediate cavity, the intermediate cavity sequentially including a first mounting cavity, an inner concave air chamber, and a second mounting cavity along its longitudinal direction, a heating jacket with a receiving chamber mounted therein, a dielectric medium disposed within the receiving chamber, the upper end of the dielectric medium extending to the outside of the heating jacket, and the lower end of the heating jacket extending into the inner concave air chamber, and an antenna holder with a ceramic rod attached to its middle portion, the ceramic rod extending into the receiving chamber and contacting the dielectric medium, a metal lead connected to an external power source wound around the ceramic rod in a spiral shape. The microwave heating chamber provided herein can reduce the size of the device, increase energy input and utilization rates, and achieve electromagnetic field volumetric heating within an effective range, achieving a balance between surface contact heating and volumetric heating.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority from a Chinese patent having application number CN202410197908.X, filed on February 22, 2024. The disclosure of the prior application is incorporated herein in its entirety. [Technical Field]

[0002] FIELD OF THE INVENTION This application is in the field of microwave heating technology, and more particularly, relates to microwave heating chambers. [Background technology]

[0003] The frequency bands commonly used in existing microwave heating technology include the L-band (890 MHz to 940 MHz) and the S-band (2400 MHz to 2500 MHz). Microwave heating technology is widely used in food processing, material drying, ceramic sintering, metal smelting, bio-sterilization lamps, microwave medicine, etc. For example, CN109764368A discloses microwave oven technology. Miniaturized, portable heating appliances mainly use resistance wire heating or electromagnetic eddy current heating, for example, CN116763017A.

[0004] Technologies such as microwave ovens use multi-feed electrical input. The advantages of this approach are that it uses volumetric heating, which is energy-saving, environmentally friendly, and has strong penetration power. However, the disadvantage is that microwave heating is theoretically affected by the microwave wavelength, making it difficult to miniaturize and unsuitable for portable devices. Resistance wire heating and electromagnetic eddy current heating, both of these heating methods, involve surface contact heating, which does not realize the heating benefits of microwave heating and has problems such as not being able to effectively carbonize dielectric media. Furthermore, resistance wire heating requires the addition of a heating sheet or heating rod to the heating chamber (compared to microwave heating). The heating sheet or heating rod penetrates the dielectric media during heating, which tends to leave residual dielectric media after heating, making the heating chamber difficult to clean. Meanwhile, electromagnetic eddy current methods do not require the addition of a heating sheet or heating rod to the heating chamber, which makes the heating chamber easier to clean, but they require the addition of an extra material, such as a metal sheet, to the dielectric media. Summary of the Invention [Problem to be solved by the invention]

[0005] The purpose of this application is to provide a microwave heating chamber that can achieve equipment miniaturization, increase energy input and utilization rates, and achieve electromagnetic field volumetric heating within an effective range. The heating method of the microwave heating chamber provided in this application is a method between surface contact heating and volumetric heating, and strikes a balance between the two methods. [Means for solving the problem]

[0006] In order to achieve the above object, the technical solution adopted in this application is as follows: A microwave heating chamber is provided, comprising a metal housing having an intermediate cavity penetrating therethrough, the intermediate cavity including a first mounting cavity, an inner concave air chamber and a second mounting cavity in sequence along its longitudinal direction; a heating jacket having a receiving chamber disposed therein is mounted in the first mounting cavity, a dielectric medium is disposed in the receiving chamber, an upper end of the dielectric medium extends to the exterior of the heating jacket, and a lower end of the heating jacket extends into the inner concave air chamber; An antenna holder having a ceramic rod attached to its middle portion is mounted in the second mounting cavity, the ceramic rod extending into the receiving chamber and contacting the dielectric medium, and a metal lead connected to an external power source is spirally wound around the outer periphery of the ceramic rod.

[0007] In one possible implementation, the metal housing is a highly conductive material and the outer wall of the metal housing is provided with an oxidation layer.

[0008] In one possible implementation, the heating jacket is a microwave-penetrable material.

[0009] In one possible implementation, the lower end of the heating jacket is provided with an end plate having a through hole in the middle for passing a ceramic rod through, the upper end of the heating jacket is provided with a cuff in the circumferential direction, and the upper end of the first mounting cavity is provided with an annular stopper groove, and the cuff is provided in the annular stopper groove so as to limit the insertion depth of the heating jacket into the inner concave air chamber.

[0010] In one possible embodiment, a recess is provided in the middle of the lower end of the dielectric medium, and the recess is provided corresponding to the through hole so as to enclose the upper end of the ceramic rod.

[0011] In one possible implementation, the length by which the lower end of the heating jacket penetrates into the internal concave air chamber is more than half the length of the internal concave air chamber.

[0012] In one possible implementation, the ceramic rod is made of an alumina or zirconia material, the outer wall of the ceramic rod is perforated with a spiral groove, and the metal lead is wound around the spiral groove.

[0013] In one possible implementation, the outer wall of the ceramic rod is provided with an insulating layer that wraps around the outside of the metal lead.

[0014] In one possible implementation, the inner concave air chamber includes an upper tapered cavity and a lower tapered cavity, the diameter of the upper tapered cavity gradually increasing from top to bottom, the diameter of the lower tapered cavity gradually increasing from bottom to top, and the lower end of the heating jacket extends into the lower tapered cavity.

[0015] In one possible embodiment, the angle between the upper tapered cavity and the central axis of the heating jacket is 20° to 45°. [Effects of the Invention]

[0016] The microwave heating chamber provided in this application has the following beneficial effects: Compared with existing technologies, the dielectric medium is inserted from top to bottom into the receiving chamber of the heating jacket, the heating jacket together with the dielectric medium is inserted from top to bottom into the intermediate cavity of the metal housing, and the heating jacket is attached to the first mounting cavity, with the lower end of the heating jacket inserted into the inner concave air chamber. A metal lead is spirally wound around a ceramic rod, and the ceramic rod is vertically attached to the antenna holder, the entire assembly being attached to the second mounting cavity. The ceramic rod extends to the inner concave air chamber, with the upper end of the ceramic rod abutting the lower end of the dielectric medium to ensure sufficient contact between them, and the metal lead is connected to a power source. An electromagnetic field is formed in the inner concave air chamber by the metal lead spirally wound around the ceramic rod, causing electromagnetic field heating of the dielectric medium. In addition, part of the microwave energy carried by the electromagnetic field is directly converted into thermal energy to heat the ceramic rod, and the ceramic rod can also heat the dielectric medium through heat conduction, so the dielectric medium is doubly heated and quickly reaches the required temperature. The microwave heating chamber provided in this application achieves equipment miniaturization, increases energy input and utilization, and achieves electromagnetic field volumetric heating within an effective range. The heating method of the microwave heating chamber provided in this application is a method between surface contact heating and volumetric heating, achieving a balance between the two. [Brief explanation of the drawings]

[0017] In the following, in order to more clearly explain the technical solutions of the embodiments of the present application, drawings necessary for explaining the embodiments or existing technologies will be briefly described. It is obvious that the drawings in the following description are only some embodiments of the present application, and a person skilled in the art can also obtain other accompanying drawings based on these drawings without any creative efforts. [Figure 1] 1 is a schematic structural diagram of a microwave heating chamber provided in the present application. [Figure 2]1 is a schematic structural diagram of a metal housing of the microwave heating chamber provided in the present application. FIG. [Figure 3] 1 is a schematic structural diagram of a heating jacket of a microwave heating chamber provided in the present application; [Figure 4] 1 is a schematic structural diagram of a dielectric medium of the microwave heating chamber provided herein; FIG. [Figure 5] 1 is a schematic structural diagram of an antenna holder, a ceramic rod, and a metal lead of the microwave heating chamber provided in the present application. [Figure 6] FIG. 2 is a schematic structural diagram of a microwave heating chamber provided in another embodiment of the present application. [Figure 7] FIG. 7 is a partial enlarged view of a portion A in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0018] In order to make the technical problems, technical solutions and beneficial effects that the present application aims to solve more clear and explicit, the present application will be described in more detail below with reference to the drawings and embodiments. It should be noted that the specific embodiments described in this specification are only for the purpose of interpreting the present application, and are not intended to limit the present application.

[0019] 1 to 5, in one embodiment, the microwave heating chamber provided in the present application includes a metal housing 1 having a through-hole formed therein, the intermediate cavity including a first mounting cavity 110, an inner concave air chamber 120, and a second mounting cavity 130 arranged in that order along its longitudinal direction, a heating jacket 2 having a receiving chamber 210 formed therein is mounted in the first mounting cavity 110, a dielectric medium 3 is disposed within the receiving chamber 210, an upper end of the dielectric medium 3 extends to the outside of the heating jacket 2, and a lower end of the heating jacket 2 extends into the inner concave air chamber 120, an antenna holder 4 having a ceramic rod 5 attached to its middle portion is mounted in the second mounting cavity 130, the ceramic rod 5 extends to the receiving chamber 210 and contacts the dielectric medium 3, and a metal lead 6 connected to an external power source is spirally wound around the outer periphery of the ceramic rod 5.

[0020] In this embodiment, compared with the existing technology, the microwave heating chamber provided in the present application has the following advantageous effects: The dielectric medium 3 is inserted from top to bottom into the receiving chamber 210 of the heating jacket 2, the heating jacket 2 together with the dielectric medium 3 is inserted from top to bottom into the intermediate cavity of the metal housing 1, and the heating jacket 2 is attached to the first mounting cavity 110, with the lower end of the heating jacket 2 inserted into the inner concave air chamber 120. A metal lead 6 is spirally wound around the ceramic rod 5, and the ceramic rod 5 is vertically attached to the antenna holder 4, and the entire assembly is attached to the second mounting cavity 130. The ceramic rod 5 extends to the inner concave air chamber 120, with the upper end of the ceramic rod 5 abutting against the lower end of the dielectric medium 3 to ensure sufficient contact between them, and the metal lead 6 is connected to a power source. An electromagnetic field is formed in the inner concave air chamber 120 by the metal lead 6 spirally wound around the ceramic rod 5. This generates electromagnetic heating for the dielectric medium 3. In addition, part of the microwave energy carried by the electromagnetic field is directly converted into thermal energy to heat the ceramic rod 5, and the ceramic rod 5 can also heat the dielectric medium 3 by heat conduction, so that the dielectric medium 3 is doubly heated and quickly reaches the required temperature. The microwave heating chamber provided in this application realizes the miniaturization of the equipment, increases the energy input and utilization rate, and realizes electromagnetic field volumetric heating within an effective range. The heating method of the microwave heating chamber provided in this application is a method between surface contact heating and volumetric heating, and strikes a balance between the two.

[0021] The dielectric medium 3 is the object to be heated, and may be a material such as flavoring, tobacco, etc., and its characteristics are that it has a large microwave attenuation coefficient, can absorb microwave energy, generate polarized molecules, and convert it into thermal energy.

[0022] Optionally, the metal housing 1 can be made of a highly conductive material, such as aluminum or copper. The metal housing 1 is used to reflect and shield microwaves and is subject to the skin effect. Theoretically, the metal housing 1 does not attenuate microwave energy, and negligible microwave energy attenuation occurs during the process. Microwave energy is reflected multiple times by the metal housing 1, which effectively converts it into thermal energy and absorbs it in the dielectric medium 3. The metal housing 1 also prevents microwave leakage and harmful radiation from damaging the human body. Optionally, an oxide layer 150 may be provided on the outer wall of the metal housing 1. The oxide layer 150 can serve as a microwave boundary. The oxide layer 150 can be manufactured by directly oxidizing the outer wall of the metal housing 1.

[0023] Alternatively, the heating jacket 2 can be made of a microwave-penetrable material, such as plastic or ceramic. The heating jacket 2 is designed to have an independent chamber body (accommodating chamber 210), which serves as the heating chamber body for accommodating the dielectric medium 3 and is easy to clean even if the dielectric medium remains on its inner wall. The dielectric medium 3 is heated by a hybrid method using two heating methods: heating by thermal conduction through the ceramic rod 5 and heating by microwaves within the inner concave air chamber 120. The hybrid heating allows the dielectric medium 3 to be heated quickly to an appropriate temperature, and microwave heating is advantageous for uniform heating.

[0024] An end plate 220 is provided at the lower end of the heating jacket 2, with a through hole 240 in the middle for passing the ceramic rod 5 through. A cuff 230 is provided circumferentially at the upper end of the heating jacket 2, and an annular stopper groove 140 is provided at the upper end of the first mounting cavity 110. The cuff 230 is provided in the annular stopper groove 140 so as to limit the insertion depth of the heating jacket 2 into the inner concave air chamber 120.

[0025] A recess 310 is provided in the middle of the lower end of the dielectric medium 3, and the recess 310 is provided corresponding to the through hole 240 so as to surround the upper end of the ceramic rod 5, thereby allowing the ceramic rod 5 to be in more sufficient contact with the dielectric medium 3 and improving the heat conduction efficiency to the dielectric medium 3.

[0026] The length by which the lower end of the heating jacket 2 penetrates into the internal concave air chamber 120 exceeds half the length of the internal concave air chamber 120, thereby allowing a larger portion of the dielectric medium 3 to be located within the internal concave air chamber 120 and receive sufficient microwave heating, thereby improving the efficiency of microwave heating of the dielectric medium 3.

[0027] The ceramic rod 5 is made of alumina or zirconia, which has the advantages of good insulation, a stable molecular structure, no polarization under the action of microwaves, and essentially no microwave attenuation. The ceramic rod 5 is used to attach a metal lead 6 to form a microwave heating chamber. A spiral groove is drilled on the outer wall of the ceramic rod 5, and the metal lead 6 is wound around the spiral groove, ensuring the stability of the state of the metal lead 6 itself.

[0028] The metal lead 6 can be made of a nickel alloy with low resistivity. The diameter of the metal wire of the metal lead 6 can be φ0.2 mm, and the metal wire is wound to a certain length around a microwave heating chamber antenna suitable for the S band (2400 MHz to 2500 MHz).

[0029] Optionally, an insulating layer can be provided on the outer wall of the ceramic rod 5, and the insulating layer can wrap around the outside of the metal lead 6. The insulating layer can be made of high-temperature glass frit, and by applying it to the outer wall of the ceramic rod 5 around which the metal lead 6 is wound, the stability of the metal lead 6 can be protected and the surface smoothness of the ceramic rod 5 can be optimized, allowing a bandwidth of 160 MHz to 180 MHz to be achieved.

[0030] Optionally, the inner concave air chamber 120 includes an upper tapered cavity 121 and a lower tapered cavity 122, the diameter of the upper tapered cavity 121 gradually increasing from top to bottom, and the diameter of the lower tapered cavity 122 gradually increasing from bottom to top, and the lower end of the heating jacket 2 extends into the lower tapered cavity 122. An alternating electromagnetic field is formed at the end of the ceramic rod 5 by the metal lead 6 spirally wound around the ceramic rod 5, and the alternating electromagnetic field formed at the upper end of the ceramic rod 5 penetrates the heating jacket 2 to microwave-heat the dielectric medium 3. The inner concave air chamber 120 facilitates upward propagation of microwaves radiated from the metal lead 6 to the dielectric medium 3, improving microwave heating efficiency. Specifically, the angle between the upper tapered cavity 121 and the central axis of the heating jacket 2 may be 20° to 45°, in which case the microwaves are transmitted within the inner concave air chamber 120, pass through the dielectric medium 3, and are converted into heat.

[0031] 6 and 7, in another embodiment, the concave air chamber 120 may be a spherical chamber, with the lower end of the heating jacket 2 positioned below the center of the spherical chamber. A plurality of tapered chambers are formed at equal intervals from top to bottom along the circumferential direction of the inner wall of the spherical cavity, and the inner diameter of the tapered chambers gradually decreases from top to bottom, forming a tapered surface along the circumferential direction of the tapered chamber. A heating layer 160 containing high-purity iron powder, gravel particles, and a catalyst may be attached to the tapered surface. The catalyst may be a mixture of activated carbon and inorganic salt. The magnetic field lines formed at the upper end of the ceramic rod 5 penetrate the heating jacket 2 and act on the heating layer 160. By changing the current on the metal lead 6, the trajectory of the magnetic field lines can be changed, causing the high-purity iron powder in the heating layer 160 to be displaced under the action of the magnetic field lines, resulting in friction between the high-purity iron powder and the gravel particles. At the same time, under the action of the catalyst, the high-purity iron powder comes into contact with the air in the inner concave air chamber 120 and oxidizes, generating heat, which further heats the dielectric medium 3 in the heating jacket 2. Combined with contact heating and electromagnetic field heating, a triple heating method is formed.

[0032] The above is only a preferred embodiment of the present application, and does not limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application should be included within the protection scope of the present application. [Explanation of symbols]

[0033] 1...metal housing, 110...first mounting cavity, 120...inner concave air chamber, 121...upper tapered cavity, 122...lower tapered cavity, 130...second mounting cavity, 140...annular stopper groove, 150...oxidation layer, 160...heat generating layer, 2...heating jacket, 210...accommodating chamber, 220...end plate, 230...cuff, 240...through hole, 3...dielectric medium, 310...recess, 4...antenna holder, 5...ceramic rod, 6...metal lead.

Claims

1. The device comprises a metal housing (1) having an intermediate cavity extending therethrough, the intermediate cavity including, in order along its length, a first mounting cavity (110), an internally recessed air chamber (120), and a second mounting cavity (130); A heating jacket (2) having a receiving chamber (210) is mounted in the first mounting cavity (110), a dielectric medium (3) is provided in the receiving chamber (210), an upper end of the dielectric medium (3) extends to the outside of the heating jacket (2), and a lower end of the heating jacket (2) extends into the inner concave air chamber (120); An antenna holder (4) having a ceramic rod (5) attached to its middle portion is attached to the second mounting cavity (130), the ceramic rod (5) extending to the receiving chamber (210) and contacting the dielectric medium (3), and a metal lead (6) connected to an external power source is spirally wound around the outer periphery of the ceramic rod (5). A microwave heating chamber characterized by:

2. The metal housing (1) is made of a highly conductive material, and an oxide layer (150) is provided on the outer wall of the metal housing (1).

2. The microwave heating chamber of claim 1.

3. The heating jacket (2) is made of a material that is penetrable by microwaves.

2. The microwave heating chamber of claim 1.

4. An end plate (220) having a through hole (240) formed in the middle for passing the ceramic rod (5) is provided at the lower end of the heating jacket (2), a cuff (230) is provided in the circumferential direction at the upper end of the heating jacket (2), and an annular stopper groove (140) is provided at the upper end of the first mounting cavity (110), and the cuff (230) is provided in the annular stopper groove (140) so as to limit the insertion depth of the heating jacket (2) into the inner concave air chamber (120).

4. The microwave heating chamber of claim 3.

5. A recess (310) is provided in the middle of the lower end of the dielectric medium (3), and the recess (310) is provided corresponding to the through hole (240) so as to surround the upper end of the ceramic rod (5).

5. The microwave heating chamber of claim 4.

6. The length by which the lower end of the heating jacket (2) penetrates into the internal concave air chamber (120) is more than half the length of the internal concave air chamber (120).

5. The microwave heating chamber of claim 4.

7. The ceramic rod (5) is made of an alumina or zirconia material, and a spiral groove is formed on the outer wall of the ceramic rod (5), and the metal lead (6) is wound around the spiral groove.

2. The microwave heating chamber of claim 1.

8. An insulating layer is provided on the outer wall of the ceramic rod (5) to wrap the outside of the metal lead (6).

8. A microwave heating chamber according to claim 7.

9. The inner concave air chamber (120) includes an upper tapered cavity (121) and a lower tapered cavity (122), the diameter of the upper tapered cavity (121) gradually increases from top to bottom, the diameter of the lower tapered cavity (122) gradually increases from bottom to top, and the lower end of the heating jacket (2) extends into the lower tapered cavity (122).

2. The microwave heating chamber of claim 1.

10. The angle between the upper tapered cavity (121) and the central axis of the heating jacket (2) is 20° to 45°; 10. The microwave heating chamber of claim 9.

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