Abstract: A commercial scale system and process for chemically modifying wood and then heating the chemically-modified wood. The system/process separates the chemical modification step from the heating step by utilizing two different vessels for the modification and heating steps. The system and process can, in certain situations, include a containment room for preventing escape of vapors from a chemical wood modification reactor, a wood heater, and/or a chemically-modified bundle of wood as the bundle is transported from the wood modification reactor to the wood heater.

Abstract: A microwave heating system configured to heat a plurality of articles and a process for using the same is provided. The heating system includes at least two laterally-spaced parallel convey lines and two or more groups of microwave launchers configured to heat articles transported along each convey line. The groups of microwave launchers can include pairs of oppositely disposed launchers that are spaced apart from one another along the axis of convey. When the system includes multiple convey lines, adjacent launcher groups are staggered relative to one another in the convey direction. Heating articles, such as foodstuffs or medical fluids or equipment in such a system, minimize undesirable interference between launchers of adjacent groups and provide a more uniform heating field.

Abstract: A microwave heater equipped with a microwave choke and suitable for heating one or more articles under vacuum. The microwave choke inhibits leakage of microwave energy between a door of the heater and a main vessel body of the heater without causing arcing at the choke, even at low pressures. In certain situations, the microwave choke can be configured with side-by-side choke cavities. In certain situations, the microwave choke can be removably coupled to the door and/or vessel body for easier fabrication, installation, and/or replacement.

Abstract: A microwave system for heating a plurality of articles and a method of using the same is provided. The microwave heating system comprises at least three microwave launchers and at least three microwave allocation devices for dividing the microwave energy into at least three separate portions. Each allocation device is configured to divide the microwave energy passing therethrough according to a predetermined ratio, and at least one of the allocation devices is configured to divide the microwave energy according to a predetermined ratio that is not 1:1. The resulting energy portions can then be discharged into the microwave heating chamber via the launchers and used to heat a plurality of articles, including foodstuffs, medical fluids, or medical instruments, disposed within the heating chamber.

Abstract: A microwave heating system configured to heat a plurality of articles is provided. The microwave heating system includes a thermalization zone for adjusting the temperature of the articles disposed therein to be substantially uniform and a microwave heating zone for heating the thermalized articles. At least one of the thermalization zone and microwave heating zone are liquid-filled and may include a plurality of fluid agitators for discharging jets of liquid medium toward the articles at multiple locations within the chamber.

Abstract: A microwave heating system for continuously heating a plurality of articles and process for using the same are provided. The microwave system includes a thermalization zone for thermalizing the articles to a substantially uniform temperature, a microwave heating zone for increasing the temperature of the articles by at least about 50° C., and a quench zone for cooling the articles after heating. The heating can be carried out at a rate of at least 25° C. per minute. The system also includes at least one conveyance system for transporting the articles through each of the thermalization, microwave heating, and quench zones. The system can be commercial-sized and may have an overall production rate of at least 20 packages per minute per convey line.

Abstract: A radio frequency (RF) heating system and process for rapidly and uniformly heating a plurality of articles on a convey line.

Abstract: A method for heating a plurality of articles according to a prescribed heating profile is provided. The method includes heating a first test article in a small-scale microwave heating system and, based on the value of one or more parameters determined during this small-scale heating, determining a prescribed heating profile for the test article. Suitable parameters can include for example, net power discharged, sequential microwave distribution, average temperature and flow rate of the fluid in the heating chamber, and residence time. The heating profile can then be used to control a commercial-scale microwave heating system used to heat a plurality of similar articles.

Abstract: A microwave heater capable of heating a bundle of wood and equipped with an optimized system for launching and/or dispersing microwave energy. The microwave launching system can include one or more split microwave launchers at least partly disposed in the interior of the heater. The microwave dispersing system can include one or more moving reflectors for rastering microwave energy emitted from the split launchers.

Abstract: A microwave heating system configured to heat a plurality of articles and a process for using the same are provided. The microwave heating system includes a liquid-filled thermalization zone, a liquid-filled microwave heating zone, and a pressure lock system disposed therebetween. The pressure lock system includes a pair of locking gate valves and a pressure adjustment chamber configured to transition the articles being heated from the thermalization zone to the microwave heating zone, which may be operated at different pressures.

Abstract: An optimized microwave barrier assembly suitable for use with a vacuum microwave heater. The barrier assembly is configured to allow microwaves to pass therethrough in a TMab mode, wherein a is 0 and b is an integer in the range of 1 to 5. The barrier assembly is also configured to maintain a pressure differential across a window of the barrier assembly. Such a configuration can reduce or eliminate arcing in the barrier assembly, even at low pressures.

Abstract: A method and system for heating a plurality of articles is provided. The method includes discharging microwave energy into a microwave chamber and passing a plurality of articles through the heating zone. At least a portion of the microwave energy discharged into the heating zone may first be phase shifted using one or more phase shifting devices. One embodiment of a rotatable phase shifting device is also provided and includes an elongated fixed member disposed proximate a rotatable housing. The phase shifting device employed by the microwave heating system is configured such that the ratio of the article residence time in the heating zone to the phase shifting rate is at least about 4:1. Rotatable phase shifting devices, or variable phase short circuits, as described herein can also be used in other applications, such as, for example, as impedance or frequency tuning devices.

Abstract: An optimized microwave barrier assembly suitable for use with a vacuum microwave heater. The barrier assembly is configured to allow microwaves to pass therethrough in a TMab mode, wherein a is 0 and b is an integer in the range of 1 to 5. The barrier assembly is also configured to maintain a pressure differential across a window of the barrier assembly. Such a configuration can reduce or eliminate arcing in the barrier assembly, even at low pressures.

Abstract: A locking gate device suitable for selectively blocking the flow of fluid and/or articles through a pair of openings defined by two spaced-apart members is provided. The spaced-apart members may be opposing walls or flanges of two adjacent processing chambers or vessels in a pressurized heating system. The locking gate device includes a gate assembly that is movable within a gate-receiving space defined between opposed sealing surfaces of the spaced-apart members. The gate assembly comprises a pair of sealing plates and a drive member shiftable relative to the sealing plates. As the drive member is shifted between a retracted position and an extended position, a pair of bearings disposed between the sealing plates and the drive member forces the sealing plates outwardly to contact the sealing surfaces of the spaced-apart members. This substantially blocks the flow-through openings defined by one or both sealing surfaces and restricts flow therethrough.

Abstract: A microwave heating system configured to heat a plurality of articles is provided. The microwave heating system includes a microwave splitter, a pair of microwave launchers, and at least one inductive iris disposed between the splitter and the launch opening of one of the launchers. A microwave launcher suitable for use in such a heating system is also provided. The launcher includes an inductive iris disposed within the interior of the launcher, spaced between its inlet and outlet and obstructing at least a portion of the microwave pathway.

Abstract: A microwave heating system configured for heating a plurality of articles is provided. One or more of the microwave launchers can be offset slightly, such that the microwave energy introduced into the heating chamber is discharged at a launch tilt angle of at least 2°. Additionally, each launcher can include a microwave-transparent window disposed between the microwave chamber and the one or more launch openings and at least 50 percent of the chamber-side surface of the window can be oriented at an angle of at least 2° from the horizontal.

Abstract: A microwave heating system configured to heat a plurality of articles and a process for using the same are provided. The microwave heating system includes a liquid-filled thermalization zone, a liquid-filled microwave heating zone, and a pressure lock system disposed therebetween. The pressure lock system includes a pair of locking gate valves and a pressure adjustment chamber configured to transition the articles being heated from the thermalization zone to the microwave heating zone, which may be operated at different pressures.

Abstract: A microwave heating system for continuously heating a plurality of articles and process for using the same are provided. The microwave system includes a thermalization zone for thermalizing the articles to a substantially uniform temperature, a microwave heating zone for increasing the temperature of the articles by at least about 50° C., and a quench zone for cooling the articles after heating. The heating can be carried out at a rate of at least 25° C. per minute. The system also includes at least one conveyance system for transporting the articles through each of the thermalization, microwave heating, and quench zones. The system can be commercial-sized and may have an overall production rate of at least 20 packages per minute per convey line.

Abstract: A method for controlling a microwave heating system is provided. The method may be used with a system having a liquid-filled microwave heating chamber and includes measuring the value of one or more microwave system parameters. Suitable parameters can include, for example, net microwave power discharged, the temperature of the liquid in the microwave chamber, the flow rate of liquid through the microwave chamber, and the speed of the conveyance system disposed within the microwave chamber. The measured value of the selected parameter is then compared to a target value for that parameter in order to determine a difference. Based on the difference, one or more actions can be taken in order to start, stop, or alter the operation of the microwave heating system.

Abstract: A microwave heating system configured to heat a plurality of articles and a process for using the same is provided. The heating system includes at least two laterally-spaced parallel convey lines and two or more groups of microwave launchers configured to heat articles transported along each convey line. The groups of microwave launchers can include pairs of oppositely disposed launchers that are spaced apart from one another along the axis of convey. When the system includes multiple convey lines, adjacent launcher groups are staggered relative to one another in the convey direction. Heating articles, such as foodstuffs or medical fluids or equipment in such a system, minimize undesirable interference between launchers of adjacent groups and provide a more uniform heating field.