Wood heater with enhanced microwave dispersing and tm-mode microwave launchers

Abstract

A microwave heater capable of heating a bundle of wood and equipped with an optimized system for introducing microwave energy into the heater is provided. Also provided is an enhanced system for launching and dispersing within the heater. The system uses one or more TMab microwave launchers to emit microwave energy in the interior of the microwave heater in a TMab mode, where a is 0 and b is an integer between 1 and 5. The TMab launchers can be configured to emit microwave energy through an open outlet that faces generally parallel to the nearest wall of the heater. In certain situations, it can be advantageous to use at least two TMab microwave launchers having open outlets that face towards one another. In certain situations, it can be advantageous to use at least two TMab microwave launchers located on generally opposite sides of the microwave heater. In certain situations, the system can also include one or more moving reflectors for dispersing microwave energy emitted from the TMab microwave launchers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Patent Application Nos. 61 / 427,030; 61 / 427,042; 61 / 427,053; 61 / 427,056; 61 / 427,064; 61 / 427,067; 61 / 427,070; 61 / 427,072; 61 / 427,075; 61 / 427,076; 61 / 427,079; and 61 / 427,080, filed Dec. 23, 2010.FIELD OF THE INVENTION[0002]This invention generally relates to microwave heating systems suitable for heating wood.BACKGROUND[0003]Electromagnetic radiation, such as microwave radiation, is a known mechanism for delivering energy to an object. The ability of electromagnetic radiation to penetrate and heat an object both rapidly and effectively has proven advantageous in many chemical and industrial processes. Further, because the use of microwave energy as a heat source is generally non-invasive, microwave heating is particularly useful in processing ‘sensitive’ dielectric materials, such as food and pharmaceuticals, and can even be useful for heating materials having a relatively poor thermal con...

AI Technical Summary

Benefits of technology

The present invention relates to a system and process for producing chemically-modified, dried, and / or thermally-modified wood using microwave energy. The system includes a microwave heater, at least one microwave generator, and a microwave distribution system for directing microwave energy to the heater. The microwave distribution system includes a first and second microwave launcher for emitting microwave energy in a TMab mode. The microwave energy is directed to the interior of the heater using a first TMab waveguide segment, a first TMab-to-TMab mode converter, and a first movable reflector. The process involves emitting microwave energy in a TMab mode through the first microwave launcher and dispersing at least a portion of the energy using the first movable reflector. The heated wood is then produced using at least a portion of the dispersed microwave energy. The technical effects of the invention include improved wood modification and energy efficiency.

Problems solved by technology

However, the complexities and nuances of safely and effectively applying microwave energy, especially on a commercial scale, have severely limited its application in several types of industrial processes.

Further, wood is generally hygroscopic, which affects its dimensional stability, and its biochemical composition makes it susceptible to attack by insects and fungi.

The latter two treatment processes generally alter the properties of wood to a more drastic degree than the others and, consequently, these types of processes typically involve more complex schemes and systems.

As a result, commercialization of these types of technologies has been limited, and multiple challenges remain to be overcome in order for these processes to be industrialized on a wide scale.

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