Microwave heating device with reflection protection

Patent metadata

Field	Value
Publication number	US-12207379-B2
Application number	US-202117480354-A
Country	US
Kind code	B2
Filing date	Sep 21, 2021
Priority date	Dec 8, 2020
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

A microwave heating device with reflection protection belongs to a technical field of microwave applications. A first port of a circulator is connected to a microwave generator, and a second port of the circulator is connected to a microwave transmission device. A water load comprises a waveguide section, a metamaterial structure layer and the absorption tube. One end of the waveguide section is connected to a third port of the circulator, and the other end is sealed by a metal plate. The metamaterial structure layer is arranged in the waveguide section, and a center of the metamaterial structure layer has an accommodation space. The absorption tube is arranged along an internal wall of the accommodation space with a spiral extending form. Both ends of the absorption tube penetrate the waveguide section, and coolant flows in the absorption tube. Relative dielectric constants of the metamaterial structure layer gradually increase.

First claim

What is claimed is:

1. A microwave heating device with reflection protection, comprising:
a microwave generator ( 22 ),
a circulator ( 23 ),
a water load ( 24 ),
a microwave transmission device ( 25 ), and
a reaction chamber ( 26 );
wherein a first port of the circulator ( 23 ) is connected to the microwave generator ( 22 ), and a second port of the circulator ( 23 ) is connected to the microwave transmission device ( 25 ); the microwave transmission device ( 25 ) is connected to the reaction chamber ( 26 ); the water load ( 24 ) comprises a waveguide section ( 21 ), a metamaterial structure layer ( 3 ) and an absorption tube ( 16 ); one end of the waveguide section ( 21 ) is connected to a third port of the circulator ( 23 ), and the other end is sealed by a metal plate; the metamaterial structure layer ( 3 ) is arranged in the waveguide section ( 21 ); a center of the metamaterial structure layer ( 3 ) has an accommodation space ( 4 ); the absorption tube ( 16 ) is arranged along an internal wall of the accommodation space ( 4 ) with a spiral extending form; both ends of the absorption tube ( 16 ) penetrate the waveguide section ( 21 ), and water flows in the absorption tube ( 16 ); relative dielectric constants of materials forming the metamaterial structure layer ( 3 ) gradually increase from outside to inside, so that microwaves passing through the metamaterial structure layer ( 3 ) are converged in the accommodation space ( 4 );
wherein the metamaterial structure layer ( 3 ) comprises multiple ring columns ( 5 ) nested in sequence from inside to outside; the accommodation space ( 4 ) is a cylindrical space with a radius of r; a radius of the metamaterial structure layer ( 3 ) is R; a relative dielectric constant of an external space of the metamaterial structure layer ( 3 ) is ε 0 ; the relative dielectric constants at each position point of the metamaterial structure layer ( 3 ) constitutes a step function; a distance between the position point and a center of the accommodation space ( 4 ) is d, and R>d>r; each step of the step function intersects with another function ε(d)=ε 0 (R/d) 2 .

2. The microwave heating device, as recited in claim 1 , wherein each of the ring columns ( 5 ) has multiple hollow cavities ( 6 ), and two ends of the multiple hollow cavities ( 6 ) are extended to a top surface and a bottom surface of a corresponding ring column ( 5 ) respectively.

3. The microwave heating device, as recited in claim 2 , wherein cross sections of the hollow cavities ( 6 ) of an outer ring column ( 5 ) are larger than cross sections of the hollow cavities ( 6 ) of an inner ring column ( 5 ).

4. The microwave heating device, as recited in claim 3 , wherein the hollow cavities ( 6 ) of the ring columns ( 5 ) are evenly spaced; a quantity of the hollow cavities ( 6 ) on each of the ring columns ( 5 ) is equal.

5. The microwave heating device, as recited in claim 4 , wherein cross sections of the hollow cavities ( 6 ) are circular, elliptical or polygonal.

6. The microwave heating device, as recited in claim 5 , wherein an opening ( 7 ) is arranged at a top of the waveguide section ( 21 ), and a press cap ( 8 ) covers the opening ( 7 ); a concave circular groove ( 9 ) is provided at a bottom of the press cap ( 8 ), which is fitted on a top of the metamaterial structure layer ( 3 ); the metamaterial structure layer ( 3 ) is sandwiched between the press cap ( 8 ) and a bottom of the waveguide section ( 21 ).

7. The microwave heating device, as recited in claim 6 , wherein the press cap ( 8 ) has a communicating cavity ( 10 ); the concave circular groove ( 9 ) has multiple micro holes ( 11 ), in such a manner that all the hollow cavities ( 6 ) as well as the accommodation space ( 4 ) communicate with the communicating cavity ( 10 ) through the micro holes ( 11 ); a safety valve ( 12 ) is provided on the press cap ( 8 ) to relieve pressure when the communicating cavity ( 10 ) is over-pressured; an L-shaped positioning plate ( 13 ) is provided at a bottom of the metamaterial structure layer ( 3 ); an L-shaped positioning groove is arranged at the bottom of the waveguide section ( 21 ), which matches with the L positioning plate ( 13 ).

8. The microwave heating device, as recited in claim 7 , wherein the two ends of the absorption tube ( 16 ) are connected to an inlet tube ( 17 ) and an outlet tube ( 19 ) respectively; the inlet tube ( 17 ) and the outlet tube ( 19 ) are wrapped with metal sleeves.

Assignees

• Univ Sichuan

Inventors

• Zhu Huacheng
• Yang Yang

Classifications

• H01P1/262

  the dissipative medium being a liquid or being cooled by a liquid · CPC title

• H01P1/38

  Circulators · CPC title

• F27D11/12

  with electromagnetic fields acting directly on the material being heated · CPC title

• H05B6/666

  Safety circuits (emergency protective circuits in general H02H) · CPC title

• H01P1/39

  Hollow waveguide circulators · CPC title