ES2623852T3 - Improved microwave heating systems - Google Patents

Abstract

A microwave system (10) for heating a plurality of articles, said system comprising: a microwave chamber (620) configured to receive said articles; a transport system (110) for transporting said articles through said microwave chamber (620) along a transport axis (642); and a first microwave launcher (622a) configured to propagate microwave energy into said microwave chamber (620) along a first central launch axis (660a), characterized in that a first launch inclination angle of at minus 2º and less than 15º is defined between said first central launching axis (660a) and a plane normal to said transport axis (66a).

Description

DESCRIPTION

Improved microwave heating systems and methods of use thereof

Field of the Invention

[0001] The invention relates to microwave systems for heating one or more objects, articles and / or loads.

Background

[0002] Electromagnetic radiation, such as microwave radiation, is a known mechanism for supplying energy to an object. The ability of electromagnetic radiation to penetrate and heat an object quickly and efficiently has proven advantageous in many chemical and industrial processes. Due to its ability to quickly and completely heat an article, microwave energy has been used in heating processes 10 in which it is desired to quickly reach a prescribed minimum temperature, such as, for example, pasteurization and / or sterilization processes. In addition, because microwave energy is generally non-invasive, microwave heating can be particularly useful for heating "sensitive" dielectric materials, such as food and pharmaceuticals. However, to date, the complexities and nuances of safely and efficiently applying microwave energy, especially on a commercial scale, have significantly limited its application in various types of industrial processes. An example of a microwave system is disclosed in FR2645391.

[0003] Therefore, there is a need for an efficient, constant and cost effective industrial-scale microwave heating system suitable for use in a wide variety of processes and applications.

 twenty

Summary

[0004] An embodiment of the present invention relates to a microwave system for heating multiple items. The system comprises a microwave chamber configured to receive the items and a conveyor system for transporting the items through the microwave chamber along a transport axis. The system also comprises a first microwave launcher configured to propagate microwave energy into a microwave chamber along a first central axis of launch, where a first angle of inclination of launch of at least 2 ° is defined and less than 15º between the first central axis of launch and a plane normal to the transport axis.

[0005] Another embodiment of the present invention relates to a microwave system for heating multiple items. The system comprises a microwave chamber configured to receive the items and a conveyor system for transporting the items through the microwave chamber along a transport axis. The system also comprises a first microwave launcher that defines at least one launch opening to discharge microwave energy into the microwave chamber; and an essentially transparent microwave window arranged between the microwave chamber and the launch opening. The window has a surface on the side of the chamber that defines a portion of the microwave chamber and at least 50 percent of the total surface area of the surface on the side of the chamber is oriented at an angle of at least 2 ° from the horizontal.

[0006] Another embodiment of the present invention relates to a process for heating multiple items in a microwave heating system, the process comprising the steps: (a) passing multiple items through a microwave heating chamber by a conveyor system, wherein the microwave heating chamber is at least partially filled with a liquid medium; (b) generate microwave energy using one or more microwave generators; (c) introducing at least a part of the microwave energy into the microwave chamber by at least one microwave launcher, where at least a portion of the microwave energy introduced into the microwave chamber is discharged according to an angle of inclination of 45 launch of at least 2º; and (d) heating the items in the microwave heating chamber using at least part of the microwave energy discharged into it.

[0007] An embodiment of the present invention relates to a microwave system for heating multiple items. The system comprises a microwave generator for generating microwave energy having a predominant wavelength 50 (λ), a conveyor system for transporting the articles along a transport axis, and a first microwave launcher for launching at least a part of the microwave energy to the items transported by the conveyor system. The first microwave launcher defines at least one launch opening with a width (W1) and a depth (D1), where W1 is greater than D1, and is characterized in that D1 is not greater than

0.625 λ.

[0008] Another embodiment of the present invention relates to a microwave system for heating multiple items. The system comprises a microwave generator to generate microwave energy with a predominant wavelength (λ), a microwave chamber configured to receive the items, and a 5 microwave distribution system to direct at least a portion of the energy from microwave from the microwave generator to the microwave chamber. The microwave distribution system comprises a first microwave launcher. The first microwave launcher defines a microwave input to receive at least a portion of the microwave energy and at least one launch opening to discharge the microwave energy into the microwave chamber. The microwave inlet has a depth (d0) and the launch opening has a depth (d1). The d0 is 10 greater than d1.

[0009] Another embodiment of the present invention relates to a microwave system for heating multiple items. The system comprises a microwave chamber configured to receive the items, a conveyor system for transporting the items through the microwave chamber along a transport axis, and a first microwave launcher that defines a microwave input and two or more launch openings configured to discharge microwave energy into the microwave chamber. The central points of the adjacent launch openings are spaced laterally from each other with respect to the transport axis.

[0010] An embodiment of the present invention relates to a microwave launcher comprising an input of 20 microwaves for receiving microwave energy with a wavelength (λ), at least one launch opening for discharging at least a portion of microwave energy, and a pair of opposite extreme pitcher walls and a pair of opposing pitcher side walls that define a microwave path between them. The microwave path is configured to allow the passage of microwave energy from the microwave inlet to the launch opening. The launcher also includes a pair of inductive iris panels respectively coupled to and extending inward from the pair of end walls. Each of the inductive iris panels partially extends within the microwave pathway to define between them an inductive iris through which at least a portion of the microwave energy sent from the microwave input to the launch opening can pass .

[0011] Another embodiment of the present invention relates to a microwave system for heating multiple items. The system comprises a microwave generator for generating microwave energy with a wavelength (λ), a microwave chamber configured to receive the items, a conveyor system for transporting the items through the microwave chamber along a transport shaft, and a microwave distribution system to direct at least a portion of the microwave energy from the microwave generator to the microwave chamber. The microwave distribution system comprises a first microwave divider to divide at least one part of the microwave energy into two or more separate portions and at least one pair of microwave launchers, each defining a microwave input and at least a launch opening to discharge microwave energy into the microwave chamber. The microwave distribution system further comprises a first inductive iris disposed between the first microwave divider and the launching opening of one of the microwave launchers. 40

[0012] A further embodiment of the present invention relates to a process for heating multiple items in a microwave heating system, the process comprising the steps: (a) passing multiple items through a microwave heating chamber at along one or more conveyor lines of a conveyor system; (b) generate microwave energy using one or more microwave generators; (c) divide at least one part of the microwave energy into two or more separate portions; (d) discharge the portions of microwave energy into the microwave heating chamber by means of two or more microwave launchers; (e) after the division of stage (c) and before the discharge of stage (d), pass at least one of the portions of microwave energy through a first inductive iris; and (f) heating the items in the microwave heating chamber using at least a portion of the microwave energy discharged into it. fifty

[0013] An embodiment of the present invention relates to a method for controlling a microwave heating system comprising the steps of (a) generating microwave energy using one or more microwave generators; (b) pass multiple items through a microwave chamber filled with water through a conveyor system; (c) directing at least a part of the microwave energy into the microwave chamber 55 by one or more microwave launchers to thereby heat at least a part of the articles; (d) during at least a part of steps (a) through (c), determine a value for one or more microwave system parameters in order to provide at least a certain parameter value; (e) compare the determined parameter value with a corresponding objective parameter value to determine a difference; and (f), depending on the difference,

perform an action with respect to the microwave heating system. The one or more parameters of the microwave system are selected from the group consisting of net microwave power, water temperature in the microwave chamber, water flow through the microwave chamber, and conveyor system speed.

[0014] Another embodiment of the present invention relates to a method that controls a microwave heating system comprising the steps of (a) generating microwave energy with at least one microwave generator; (b) pass at least part of the microwave energy through a first waveguide segment; (c) discharge at least a portion of the microwave energy from the first waveguide segment into the microwave chamber by at least one microwave launcher in order to heat multiple items; (d) determine a first net power value discharged from the microwave launcher using a first pair of 10 directional couplers; (e) determine a second value of net power discharged from the microwave launcher using a second pair of directional couplers, wherein the pairs of first and second directional couplers are independent of each other; (f) compare the first value and the second value to determine a first difference; and (g) perform an action with respect to the microwave heating system when the difference is greater than a predetermined amount. fifteen

[0015] An embodiment of the present invention relates to a variable phase short circuit device for use in a microwave heating system. The device comprises a fixed section defining an essentially rectangular opening and a rotating section comprising a housing and a plurality of separate, essentially parallel plates, received in the housing. The housing comprises opposite first and second ends and the first end defines a second opening adjacent to the first opening of the fixed section. Each of the plates is coupled to the second end of the housing and generally extends to the first and second openings. The rotary section is configured to rotate relative to the fixed section on a rotation axis that extends through the first and second openings.

 25

[0016] Another embodiment of the present invention relates to a method for heating multiple articles in a microwave heating system comprising the steps of (a) passing the articles through a heating zone of a microwave chamber by means of a conveyor system, where each of the articles is kept within the heating zone for a period of permanence of article (τ); (b) generate microwave energy with one or more microwave generators; (c) passing at least a portion of the microwave energy through a phase change device configured to cyclically change the phase of the microwave energy at a rate of phase change (t); (d) discharging at least a portion of the microwave energy exiting the phase change device into the heating zone by at least one microwave launcher; and (e) heating the articles in the heating zone with at least a part of the microwave energy discharged therein, where the ratio of the article residence time and the phase change rate (τ: t) is of at least 35 4: 1.

[0017] An embodiment of the present invention relates to a microwave system for heating multiple items. The system comprises at least one microwave generator for generating microwave energy, a microwave chamber, a conveyor system for transporting the articles through the microwave chamber, and a microwave distribution system 40 for directing at least a portion of Microwave energy from the microwave generator to the microwave chamber. The microwave distribution system comprises at least three microwave allocation devices to divide microwave energy into at least three separate portions. The microwave distribution system further comprises at least three microwave launchers to discharge the separate portions of microwave energy into the microwave chamber. Each of the microwave assignment devices is configured to divide microwave energy according to a predetermined power ratio, wherein the predetermined power ratio for at least one of the microwave assignment devices is not 1: 1. .

[0018] Another embodiment of the present invention relates to a process for heating multiple items using microwave energy comprising the steps of: (a) introducing the initial amount of microwave power into a microwave distribution device; (b) use the microwave distribution device to divide the initial amount of microwave power into a first launch microwave fraction and a first distribution microwave fraction, where the power ratio of the first launch microwave fraction and the first fraction of microwave distribution is not 1: 1; (c) use the microwave distribution device to divide the first distribution microwave fraction into a second launch microwave fraction and a second distribution microwave fraction; (d) introducing the first launch microwave fraction into a microwave heating chamber by means of a first microwave launcher; and (e) introducing the second launch microwave fraction into the microwave heating chamber by means of a second launcher

of microwave.

[0019] An embodiment of the present invention relates to a continuous process for heating multiple articles in a microwave heating system comprising the steps of (a) thermalizing the articles in a thermalization zone in order to provide multiple thermalized articles with a essentially uniform temperature; (b) 5 heating the thermalized articles in a microwave heating zone in order to increase the average temperature of each article by at least 50 ° C, where at least a portion of the heating is carried out at a heating rate of at minus 25 ° C per minute; and (c) cooling the heated items in a cooling zone. The articles pass through each of the thermalization zone, the microwave heating zone and the cooling zone by means of one or more conveyor systems, where the heating system has a total production rate of at least 20 packages per minute per transport line.

[0020] Another embodiment of the present invention relates to a microwave system for heating multiple items. The system comprises a thermalization chamber for thermalizing the articles at an essentially uniform temperature, a microwave heating chamber disposed downstream of the thermalization chamber for heating the thermalized articles, and a cooling chamber arranged downstream of the chamber of microwave heating to cool items heated to a lower temperature. The microwave heating chamber is configured to increase the average temperature of the articles by at least 50 ° C at a heating rate of at least 25 ° C per minute. The system comprises at least one transport system configured to transport the articles through the thermalization chamber, the microwave heating chamber, and the cooling chamber. The microwave system is configured to achieve a total production speed of at least 20 packages per minute per transport line.

[0021] An embodiment of the present invention relates to a process for heating multiple items in a microwave heating system comprising the steps of (a) passing the items through a pressurized microwave chamber 25 through a conveyor system, wherein the microwave chamber is at least partially filled with a liquid medium; (b) generate microwave energy by one or more microwave generators; (c) introducing at least a portion of microwave energy into the microwave chamber by means of one or more microwave launchers; (d) heating the items in the microwave chamber using at least a portion of the microwave energy introduced into it; and (e) during at least a portion of the heating stage 30 (d), stirring at least a portion of the liquid medium into the microwave chamber, wherein said stirring includes discharging multiple jets of fluid to the items in multiple positions inside the microwave chamber.

[0022] Another embodiment of the present invention relates to a process for heating multiple articles in a microwave heating system comprising the steps of (a) thermalizing the articles in a thermalization chamber filled at least partially with a liquid medium to thereby produce thermal articles with a substantially uniform temperature; and (b) heat the thermalized items in a microwave chamber. The thermalization of step (a) includes discharging multiple jets of the liquid medium to the items in multiple positions within the thermalization chamber.

 40

[0023] An embodiment of the present invention relates to a closing gate device comprising a pair of spaced fixed elements having opposite sealing surfaces and defining a gate receiving space between the sealing surfaces, wherein each one of the fixed elements defines a flow passage opening limited by one of the sealing surfaces, wherein the flow passage openings are substantially aligned with each other; and a movable gate assembly within the gate receiving space 45 between a closed position where the gate assembly substantially blocks the flow passage openings and an open position where the gate assembly does not substantially block the flow passage openings. The gate assembly comprises a pair of sealing plates separated from each other and an actuating element disposed between the sealing plates, where when the gate assembly is in the closed position the actuating element is movable relative to the sealing plates. between a retracted position and an extended position 50. The gate assembly further comprises at least one pair of bearings arranged between the sealing plates, wherein the movement of the actuating element from the retracted position to the extended position causes the bearings to force the sealing plates to separate from each other and towards a sealed position, where the sealing plates couple opposite sealing surfaces, where the movement of the actuating element from the extended position to the retracted position allows the sealing plates to retract from each other 55 and to an unsealed position where the sealing plates are decoupled from the opposite sealing surfaces.

[0024] Another embodiment of the present invention relates to a method of moving one or more articles within a pressurized system comprising the steps of (a) passing one or more articles from a first pressurized zone

from process to a second pressurized process zone through a flow passage opening; (b) move a pair of movable plates into the opening; (c) separating the plates from each other so as to seal the plates against a pair of opposite sealing surfaces that define the opening at least partially, where the pair of sealed plates substantially isolate the first and second process zone from each other; (d) create a differential pressure of at least 15 psig on the pair of sealed plates; (e) depressurize at least one of the first and second process zones to equalize the pressure on the pair of sealed plates; (f) move the plates towards each other in order to detach the plates from the sealing surfaces; (g) move the pair of plates out of the opening; and (h) removing the articles from the second process zone and bringing them back to the first process zone through the flow passage opening and / or inserting a new article in the second process zone through the opening of flow path.

 10

[0025] An embodiment of the present invention relates to a microwave heating system for heating multiple items. The system comprises a thermal chamber filled with liquid, a microwave chamber filled with liquid configured to operate at a pressure greater than that of the thermalization chamber, and a pressure blocking system disposed between the thermalization chamber and the heat chamber. microwave. The pressure blocking system comprises a pressure adjustment chamber, a first closing gate valve, and a second closing gate valve, wherein the first closing gate valve is coupled between the thermalization chamber and the pressure adjustment chamber, wherein the second closing gate valve is coupled between the pressure adjustment chamber and the microwave chamber.

[0026] Another embodiment of the present invention relates to a process for heating multiple items in a microwave heating system 20 comprising (a) passing a plurality of items through a liquid filled thermalization zone to thereby provide multiple thermalized articles; (b) introducing at least a part of the thermalized articles in a pressure adjustment zone, where the pressure adjustment zone is defined at least partially between a first and a second closing gate valve, in which the first shut-off valve is in a first position open at least during a part of the introduction stage; (c) 25 after the thermalized articles have been introduced into the pressure adjustment zone, move the first closing gate valve from the first open position to the first closed position in order to substantially isolate the pressure adjustment zone from the thermalization zone; (d) move the second shut-off gate valve from a second closed position to a second open position to allow the items to be transferred from the pressure adjustment zone to a microwave heating zone filled with liquid; and (e) 30 after the items have been removed from the pressure adjustment zone, move the second shut-off valve from the second open position back to the second closed position in order to re-isolate the adjustment zone pressure of the microwave heating zone.

[0027] An embodiment of the present invention relates to a method for heating multiple articles comprising the steps of (a) heating a first test article in a small-scale model of a microwave heating system while transporting the first test article through a small-scale microwave chamber filled with water that has a total internal volume of less than 50 cubic feet, where at least part of the heating stage (a) is performed using microwave energy ; (b) determining a first prescribed heating profile based on the heating of step (a), wherein the prescribed heating profile comprises at least 40 value for one or more microwave system parameters selected from the group consisting of power net discharged into the chamber, sequential distribution of microwave power, average temperature of the water in the microwave chamber, water flow rate in the microwave chamber, and residence time of the article in the microwave chamber; and (c) heating a plurality of first commercial items in a large-scale microwave heating system while the first commercial items are transported through a large-scale microwave chamber filled with water having a total internal volume of at minus 250 cubic feet. At least a portion of the heating of stage (c) is performed using microwave energy and wherein each of the first commercial articles is substantially similar in size and composition to the first test article, wherein the heating of the stage (c ) is controlled with the first heating profile prescribed in step (b).

Brief Description of the Drawings 50

[0028]

Fig. 1a is a process flow diagram describing an embodiment of a microwave heating system for heating one or more articles, particularly illustrating a system comprising a thermalization zone, a microwave heating zone, a zone optional permanence, a cooling zone, and a couple of pressure adjustment zones; 55

Fig. 1b is a schematic diagram of a microwave heating system 10 configured according to an embodiment of the present invention, in particular each of the zones of the heating system 10

by microwave indicated in the diagram provided in Fig. 1a;

Fig. 2a is a cross-sectional schematic end view of a process vessel configured according to an embodiment of the present invention, illustrating in particular a conveyor system that includes a pair of transport lines arranged in a parallel configuration;

Fig. 2b is a schematic top sectional view of the process vessel shown in Fig. 2b which 5 illustrates in particular the arrangement of laterally spaced transport lines relative to the transport axis extending through the container;

Fig. 2c is a cross-sectional schematic end view of another process vessel configured according to another embodiment of the present invention, particularly illustrating a conveyor system that includes a pair of transport lines arranged in a stacked configuration; 10

Fig. 2d is a schematic side sectional view of the process vessel shown in Fig. 2c, illustrating, in particular, the arrangement of transport lines spaced vertically with respect to the transport axis extending through the container;

Fig. 3 is a perspective view of a carrier according to an embodiment of the present invention configured to secure and transport items that are being heated through a process vessel filled with liquid;

Fig. 4a is a partial side sectional view of an embodiment of a microwave heating system that includes a pressure adjustment zone configured to transport one or more items from the thermalization zone to the microwave heating zone of the system heating using a carrier transfer system; twenty

Fig. 4b is a partial side sectional view of another embodiment of a microwave heating system that includes a pressure adjustment zone similar to that shown in Fig. 4a, but particularly illustrating a carrier transfer system arranged almost completely within the pressure adjustment zone;

Fig. 4c is a partial schematic view of the pressure adjustment zone similar to those shown in Figs. 4a and 4b, but illustrating another embodiment of the carrier transfer system for moving the articles from the thermalization zone to the microwave heating zone;

Fig. 4d is a partial schematic view of the pressure adjustment zone similar to those depicted in Figs. 4a and 4b, but illustrating yet another embodiment of the carrier transfer system for moving the articles from the thermalization zone to the microwave heating zone; 30

Fig. 5a is a partial side sectional view of a closing gate device configured in accordance with an embodiment of the present invention, particularly illustrating the gate assembly in an open position;

Fig. 5b is a partial side sectional view of the closing gate device shown in Fig. 5a, which in particular illustrates the gate assembly in a closed position with the sealing plates in a retracted position;

Fig. 5c is a partial side sectional view of the closing gate device described in Figs. 5a and 5b, which particularly illustrates the gate assembly in a closed position with the sealing plates in an extended position;

Fig. 5d is an enlarged partial view of the gate assembly described in Figs. 5a-c, illustrating in particular an embodiment of a bearing used to move the sealing plates of the gate assembly;

Fig. 6a is a partial partial schematic sectional view of a microwave heating zone configured in accordance with an embodiment of the present invention, illustrating in particular the heating vessel and the microwave distribution system;

Fig. 6b is a schematic top view of a microwave heating zone configured in accordance with an embodiment of the present invention illustrating in particular a configuration of microwave launchers in a heating system using a multi-line transport system;

Fig. 6c is a schematic side view of the microwave heating zone illustrated in Fig. 6b, illustrating in particular a group of microwave launchers configured to heat items that pass along a transport line; fifty

Fig. 7a is a partial side sectional view of a microwave heating zone configured according to an embodiment of the present invention, which illustrates in particular an inclined microwave launcher and where the meaning of the term "tilt angle of launch "(ß);

Fig. 7b is a partial side sectional view of another embodiment of a microwave heating zone, illustrating, in particular, a microwave distribution system comprising a plurality of inclined pitchers;

Fig. 8a is an enlarged partial side view in section of a portion of a microwave heating zone, particularly illustrating an embodiment of a microwave window located near the discharge opening of at least one microwave launcher in the area of heating;

Fig. 8b is an enlarged partial side view in section of a portion of a microwave heating zone, particularly illustrating another embodiment of a microwave window located near the discharge opening of at least one microwave launcher in the area of heating;

Fig. 8c is an enlarged partial side view in section of a portion of a microwave heating zone, particularly illustrating another embodiment of a microwave window located near the discharge opening of at least one microwave launcher of the heating zone;

Fig. 9a is an isometric view of a microwave launcher configured according to an embodiment of the present invention;

Fig. 9b is a longitudinal side view of the microwave launcher shown in Fig. 9a;

Fig. 9c is an end view of the microwave launcher depicted in Figures 9a and 9b, illustrating particularly a launcher with a flared outlet;

Fig. 9d is an end view of another embodiment of the microwave launcher shown generally in Figures 9a and 9b, which particularly illustrates a launcher with an inlet and outlet of approximately the same size;

Fig. 9e is an end view of yet another embodiment of the microwave launcher shown in general in Figures 9a and 9b, which particularly illustrates a launcher having a conical outlet;

Fig. 10a is an isometric view of another microwave launcher configured in accordance with an embodiment of the present invention, particularly illustrating a launcher comprising a single microwave input and multiple microwave outputs;

Fig. 10b is a vertical cross-sectional view of the microwave launcher illustrated in Fig. 10a, which particularly illustrates the multiple microwave outputs;

Fig. 10c is a vertical cross-sectional view of the microwave launcher depicted in Figures 10a and 10b, particularly showing the pair of partition walls used to create individual microwave paths between the input and the multiple outputs of the microwave launcher;

Fig. 11a is an isometric view of a microwave launcher configured according to another embodiment of the present invention, particularly showing an integrated inductive iris disposed between the inlet and the outlet of the launcher;

Fig. 11b is a horizontal cross-sectional view of the microwave launcher illustrated in Fig. 11a;

Fig. 11c is a horizontal cross-sectional view of another microwave launcher similar to the launcher depicted in Fig. 11a, but including a pair of partition walls in addition to an inductive iris 30 disposed between the inlet and the outlet of the launcher ;

Fig. 12a is a side sectional view of a phase change device configured according to an embodiment of the present invention, particularly illustrating a piston tuning device that includes a single piston;

Fig. 12b is a schematic side sectional view of a phase change device configured according to another embodiment of the present invention, particularly illustrating a piston tuning device that includes multiple pistons driven by a common rotary axis;

Fig. 13a is a side perspective view of a phase change device configured according to yet another embodiment of the present invention, particularly illustrating a rotating phase change device; 40

Fig. 13b is a longitudinal cross-sectional view of the rotary phase change device shown in Fig. 13a;

Fig. 13c is a cross-sectional side view of the rotating section of the rotating phase change device shown in Figs. 13a and 13b, which particularly shows the width and spacing of the plates arranged inside the housing; Four. Five

Fig. 13d is a cross-sectional side view of the fixed section of the rotating phase change device shown in Figs. 13a and 13b, which particularly illustrates the dimensions of the fixed section;

Fig. 13e is a side sectional view of a rotating phase change device configured in accordance with another embodiment of the present invention, particularly illustrating a drive system that includes a rotating crank element; fifty

Fig. 13f is a side sectional view of a rotating phase change device configured according to yet another embodiment of the present invention, particularly illustrating a drive system that includes a group of compression springs;

Fig. 14a is a partial schematic side and sectional view of a microwave distribution system using two phase change devices for phase change and / or impedance tuning; 55

Fig. 14b is a partial schematic side sectional view of a microwave heating vessel configured in accordance with an embodiment of the present invention, particularly illustrating a phase change device coupled to the container for use as a frequency tuner; 15a is a partial schematic side sectional view of a portion of a microwave heating system, illustrating

particularly a thermalization zone that includes multiple fluid jet agitators;

Fig. 15b is an end view of a thermalization zone similar to that shown in Fig. 15a, particularly illustrating an embodiment in which the fluid jet agitator is circumferentially positioned within the thermalization zone;

Fig. 16 is a flow chart representing the main steps of a method for controlling a microwave system according to an embodiment of the present invention;

Fig. 17 is a flow chart depicting the main steps of a method for determining the net power discharged from at least one microwave launcher that uses two or more pairs of directional couplers; Y

Fig. 18 is an isometric representation of the location of the thermocouples inserted in a test package to determine the minimum temperature of the container for determining the heating profile for an article according to an embodiment of the present invention.

Detailed description

 fifteen

[0029] The microwave processes and system for heating multiple items according to various embodiments of the present invention are described below. Examples of articles suitable for heating in systems and processes of the present invention may include, but are not limited to, food, medical fluids and medical instruments. In one embodiment, the microwave systems described herein can be used to pasteurize and / or sterilize items that are heated. In general, pasteurization implies rapid heating of an article or 20 articles at a minimum temperature of between 80 ° C and 100 ° C, while sterilization implies heating of one or more articles at a minimum temperature of between 100 ° C and 140 ° C. However, in one embodiment, pasteurization and sterilization can be carried out simultaneously or almost simultaneously and it is possible to configure many processes and systems both to pasteurize and to sterilize one or more items. Various embodiments of microwave systems and processes configured to heat one or more types of articles will be described in detail and with reference to the Figures.

[0030] Referring now to Figures 1a and 1b, a schematic representation of the main stages in a microwave heating process according to an embodiment of the present invention is described in Figure 1a, while Figure 1b represents an embodiment of a microwave system 10 operable to heat multiple 30 items according to the process described in Figure 1a. As shown in Figures 1a and 1b, one or more articles may be initially introduced into a thermalization zone 12, where the articles may be thermally heated at a substantially uniform temperature. Once thermalized, the articles can then be optionally passed through a pressure adjustment zone 14a before being introduced into a microwave heating zone 16. In the microwave heating zone 16, the articles can be quickly heated using energy of microwaves discharged into at least a part of the heating zone by one or more microwave launchers, generally illustrated as launchers 18 in Figure 1b. The heated articles can then be optionally passed through a permanence zone 20, where the articles can be kept at a constant temperature for a certain amount of time. Then, the articles can then be passed to a cooling zone 22, where the temperature of the articles can be rapidly reduced to a suitable handling temperature. After that, the cooled articles may optionally be passed through a second pressure adjustment zone 14b before being removed from the system 10 and subsequently used.

[0031] Microwave system 10 can be configured to heat many different types of items. In one embodiment, the items heated in the microwave system 10 may comprise foods, such as, for example, 45 fruits, vegetables, meats, pastes, prepared foods, and even beverages. In other embodiments, items heated in a microwave system 10 may comprise packaged medical fluids or medical and / or dental instruments. The items processed within the microwave heating system 10 can be of any suitable size or shape. In one embodiment, each article may have a length (longer dimension) of at least about 2 inches, at least about 4 inches, at least about 6 inches and / or no more than about 18 inches, no more than about 12 50 inches , or not more than about 10 inches; a width (second longest dimension) of at least about 1 inch, at least about 2 inches, at least about 4 inches and / or no more than about 12 inches, no more than about 10 inches, or no more than about 8 inches ; and / or a depth (shorter dimension) of at least about 0.5 inches, at least about 1 inch, at least about 2 inches and / or no more than about 8 inches, no more than about 6 inches, no more than about 4 inches. The items may comprise individual items or packages that have a generally rectangular or prism-like shape or may comprise a continuous band of connected items or packages that pass through the microwave system 10. The items or packages may be constructed of any material , including plastics, cellulose, and other microwave transparent materials, and can be passed through a microwave system 10 by one or more conveyor systems, whose embodiments are

will describe in detail below.

[0032] According to an embodiment of the present invention, each of the described zones of thermalization, microwave heating, permanence and / or cooling 12, 16, 20, and 22 can be defined within a single container, as represented by general form in Figure 1b, while, in another embodiment, at least one of the steps described above can be defined within one or more separate containers. According to one embodiment, at least one of the steps described above can be carried out in a container that is at least partially filled with a fluid medium in which the items being processed can be at least partially submerged. The fluid medium may be a gas or a liquid having a dielectric constant greater than the dielectric constant of the air and, in one embodiment, it may be a liquid medium having a dielectric constant similar to the dielectric constant of the 10 items being processing Water (or liquid medium comprising water) may be particularly suitable for systems used to heat edible items and / or medical devices and devices. In one embodiment, additives such as, for example, oils, alcohols, glycols and salts may optionally be added to the liquid medium to alter or improve their physical properties (eg, boiling point) during processing, if necessary. fifteen

[0033] The microwave system 10 may include at least one conveyor system (not shown in Figures 1a and 1b) for transporting the articles through one or more of the processing zones described above. Examples of suitable conveyor systems may include, but are not limited to, plastic or rubber conveyor belts, chain conveyors, roller conveyors, flexible or multiflex conveyors, wire mesh conveyors 20, bucket conveyors, pneumatic conveyors, conveyors screw, channel or vibrating conveyors, and combinations thereof. The conveyor system can include any number of individual transport lines and can be disposed in any suitable manner within the process vessels. The conveyor system used by the microwave system 10 may be configured in a generally fixed position within the container or at least a portion of the system may be adjusted in the lateral or vertical direction.

[0034] Turning now to Figures 2a-2d, embodiments of a process vessel 120 are provided which includes a conveyor system 110 disposed therein. In an embodiment generally depicted in Figures 2a and 2b, the conveyor system 110 includes a pair of essentially parallel laterally spaced transport lines 30, 112, positioned in a generally juxtaposed configuration within the container 120. As shown in the top view in cutting of the container 120 in Figure 2b, the transport lines 112 and 114 may be laterally spaced from one another and may be positioned on both sides of a transport axis 122, which extends along the length of the container 120 in the transport address of the items that pass through it. Although in Figure 2a it is shown as if they were generally at the same vertical elevation within the container 120, it should be understood that, in one embodiment, the transport lines 112, 114 can also be placed at different vertical elevations. In addition, the conveyor system 110 shown in Figures 2a and 2b may also include multiple pairs of laterally separated transport lines (embodiment not shown), so that the pairs of laterally separated transport lines are vertically separated from each other along the vertical dimension of the container 120. 40

[0035] Another embodiment of a conveyor system 110 that includes a pair of transport lines 116, 118 vertically spaced, substantially parallel and placed in a stacked arrangement within the interior of the container 120, is shown in Figures 2c and 2d. The transport lines 116 and 118 may be configured above or below the transport axis 122, which may generally extend along the length of the container 120, as shown in the sectional side view of the container 120 provided in the Figure 2d In addition, in a manner similar to that described above, the container 120 shown in Figures 2c and 2d may also include multiple pairs of transport lines, spaced laterally from each other within the container. In addition, each pair transport line may or may not be offset from the other in a lateral direction. In a further embodiment (not shown), the container 120 may include a single transport line, positioned in the middle third of the internal volume of the container 120, or 50 placed on or near the center line of the container. Additional details of conveyor systems according to various embodiments of the present invention will be described in detail below.

[0036] When a conveyor system is used to transport items through a process vessel filled with liquid, one or more carriers or other securing mechanisms can be used to control the position of the 55 items during passage through the medium. liquid. An embodiment of a suitable carrier 210 is illustrated in Figure 3. As shown in Figure 3, the carrier 210 comprises a lower clamping surface 212a and an upper clamping surface 212b configured to hold any suitable amount of articles 216 between them. . In one embodiment, the upper and / or lower surfaces 212b, may have a mesh, grid or grill structure,

as generally shown in Figure 3, while, in another embodiment, one or both surfaces 212a, b may have a substantially continuous surface. The carrier 210 may be constructed of plastic, fiberglass, or any other dielectric material and, in one embodiment, may be made of one or more microwave compatible materials and / or microwave transparent. In some embodiments, the material may be a dissipative material. In some embodiments, carrier 210 may comprise virtually no metal. 5

[0037] The upper and lower fixing surfaces 212a, 212b can be joined together by a fixing device, which is shown as a joining means 219 in Figure 3, and, once mounted, the carrier 210 can be attached or be fixed to the conveyor system (not shown in Figure 3) according to any suitable joining mechanism. In one embodiment, at least one side (or edge) of the carrier 210 may include one or more attachment mechanisms such as, for example, upper and lower hooks 218a, 218b shown in Figure 3, to fix the carrier 210 to a part (for example, a bar, a rail, a belt, or a chain) of the conveyor system (not shown). Depending on the thickness and / or weight of the articles 216, the carrier 210 may include only one of hooks 218a, 218b to hold the carrier 210 on the conveyor system. The conveyor system used to transport articles 216 can be configured to transport multiple carriers along one or more transport lines and the carriers can be arranged in a juxtaposed and laterally separated configuration and / or a vertically stacked and separated configuration as described above. . When the transport system includes multiple transport lines, each transport line may include a single carrier to hold multiple items 216, or each transport line may keep multiple carriers stacked or separated laterally from each other.

 twenty

[0038] Referring again to Figures 1a and 1b, the items included in the microwave system 10 are initially introduced into a thermalization zone 12, where the items are thermalized to reach a substantially uniform temperature. In one embodiment, at least about 85 percent, at least 90 percent, at least 95 percent, at least 97 percent, or at least 99 percent of all items removed from the thermalization zone 12 they have a temperature of about 5 ° C, 2 ° C, or 1 ° C to each other. As used herein, the terms "thermalize" and "thermalization" generally refer to a stage of equilibration or temperature equalization. Depending on the initial and desired temperature of the items being thermalized, the temperature control system of the thermal zone 12, illustrated in Figure 1a as a heat exchanger 13, can be a heating and / or cooling system. In one embodiment, the thermalization step can be carried out at room temperature and / or pressure, while, in another embodiment, the thermalization can be carried out in a pressurized and / or liquid filled thermalization vessel at a pressure of no more than about 10 psig, no more than about 5 psig or no more than about 2 psig. The articles that are subjected to thermalization can have an average residence time in a thermal zone 12 of at least about 30 seconds, of at least about 1 minute, of at least about 2 minutes, of at least about 4 minutes and / or no more than about 20 minutes, no more than about 15 minutes, or no more than about 10 minutes. In one embodiment, the articles removed from the thermalization zone 12 may have a temperature of at least about 20 ° C, of at least about 25 ° C, of at least about 30 ° C, of at least about 35 ° C and / or of no more than about 70 ° C, no more than about 65 ° C, no more than about 60 ° C, or no more than about 55 ° C.

[0039] In an embodiment in which the thermalization zone 12 and the microwave heating zone 16 are operated at substantially different pressures, the articles removed from the thermalization zone 12 may first be passed through a zone of adjustment of pressure 14a before entering the microwave heating zone 16, as generally shown in Figures 1a and 1b. The pressure adjustment zone 14a can be any zone or system configured to transition the items that are being heated between a smaller pressure area and a larger pressure area. In one embodiment, the pressure adjustment zone 14a can be configured for the transition of the 45 articles between two zones having a pressure difference of at least about 1 psi, of at least about 5 psi, of at least about 10 psi and / or no more than about 50 psi, no more than about 45 psi, no more than about 40 psi, or no more than about 35 psi. In one embodiment, the microwave system 10 may include at least two pressure adjustment zones 14a, b as transition zones for the articles from an atmospheric pressure thermalization zone to a heating zone operating at a high pressure before cause the items to return to atmospheric pressure 50, as described in detail below.

[0040] An embodiment of a pressure adjustment zone 314a disposed between a thermalization zone 312 and a microwave heating zone 316 of a microwave heating system 310 is illustrated in Figure 4a. Pressure adjustment zone 314a is configured for transition of multiple articles 350, which may be fixed within at least one carrier, from a lower pressure thermalization zone 312 and a microwave pressure zone of greater pressure 316. A Although in Figure 4a it is shown as a single carrier 352a, it should be understood that the pressure adjustment zone 314a may be configured to receive more than one carrier. In one embodiment, the carriers can be received simultaneously, so that the adjustment zone of

Pressure 314a contains multiple carriers at once. In another embodiment, multiple carriers may be aligned and ready, for example, within the thermalization zone 312, to be moved through the pressure adjustment zone 314a, the details of which will be described below.

[0041] In operation, one or more carriers 352a can be moved from the thermalization zone 312 to the microwave heating zone 5, first, by opening a balancing valve 330 and allowing the pressure between the thermalization zone 312 and pressure adjustment zone 314a is equalized. Next, a gate device 332 can be opened to allow the carrier 352a to move from a transport line 340a disposed within the thermalization zone 312 to a platform 334 within the pressure adjustment zone 314a, as shown in Figure 4a in general by the dotted carrier 352b. 10

[0042] After that, the gate device 332 and the balancing valve 330 can be closed in sequence, re-isolating the pressure adjustment zone 314a from the thermalization zone 312. Next, another balancing valve can be opened 336 to allow the pressure to equalize between the pressure adjustment zone 314a and the microwave heating zone 316. Once equilibrium has been achieved, another gate device 338 can be opened to allow carrier 352b to move towards another conveyor system 340b disposed within the microwave heating zone 316, as shown generally in the dotted line carrier 352c in Figure 4a. Next, the gate device 338 and the balancing valve 336 can be closed in sequence, re-isolating the microwave heating zone 316 from the pressure adjustment zone 314a. The process can then be repeated to transport additional carriers from thermalization zone 312 to microwave heating zone 316 as necessary.

[0043] According to one embodiment, each of the microwave heating zones 316 and thermalization 312 can be filled 5 with a non-compressible fluid or liquid such as water or solutions that include water. As used herein, the term "full" implies a configuration in which at least 50 percent of the specified volume is filled with the filling medium. The "filling medium" may be a liquid, typically a non-compressible liquid and may be or include, for example, water. In some embodiments, "filled" volumes may be at least 75 percent, at least 90 percent, at least 95 percent, or 100 percent full of the filling medium. When the thermalization zone 312 and / or the microwave heating zone 316 are filled with a non-compressible fluid, the devices 332, 338 and / or pressure adjustment zone 314a may also include two or more fins or unidirectional valves, shown as valves or fins 342, 344 in Figure 4a, to avoid substantial fluid leaks between the thermalization zone 312 and the microwave heating zone 316 when the gate devices 332 and 338 are open and the carrier 352 passes among them.

[0044] The transport of the carrier 352 from the thermalization zone 312 through the pressure adjustment zone 314a 35 and to the microwave heating zone 316 can be carried out by one or more automatic article transfer systems, some of whose different embodiments are illustrated in Figures 4b-4d. In some embodiments, the automatic transfer system 380 may include one or more transfer devices, arranged within the thermalization zone 312, the pressure adjustment zone 314a, and / or the microwave heating zone 316 to move the carrier 352 in and / or out of the pressure adjustment zone 314a. In one embodiment shown in Figure 4b, the transfer system 380 includes two gear transfer devices 381, 382 configured to engage teeth 353 arranged along the lower edge of the carrier 352 and rotate, as indicated by arrows 392a, b for pulling the carrier 352 out of the thermalization zone 312 and / or pushing the carrier 352 towards the microwave heating zone 316. As shown in Figure 4b, the first and second gear transfer device 381, 382 are maintained substantially fixed (in terms of lateral movement) during transport of the carrier 352 and are almost entirely, or entirely, disposed within the pressure adjustment zone 314a.

[0045] On the contrary, some embodiments of the automatic transfer system 380 may include one or more transfer devices that can be moved laterally (ie, can move in the direction of transport) during the transport of the carrier 352 inward and / or outside the pressure adjustment zone 314a. As depicted in an embodiment shown in Figure 4c, a portion of the automatic transfer system 380 may be arranged in the thermalization zone 312 and / or the microwave heating zone 316 and may be configured to extend to or retract from the zone pressure adjustment 314a. In the system 380 shown in Figure 4c, the transfer devices include a pusher arm 381 configured to push the carrier 352 55 towards the pressure adjustment zone 314a and a pull arm 382 to pull the carrier 352 towards the zone of microwave heating 316. Neither the pushing arm 381 nor the pulling arm 382 are disposed within the pressure adjustment zone 314a; on the contrary, each is configured to extend to and retract from the pressure adjustment zone 314a, as shown generally with the arrows 394a, b in Figure 4c.

[0046] According to another embodiment depicted in Figure 4d, the automatic transport system 380 includes a platform 334 that has a movable part 384, which is configured to extend to and retract from the thermalization zone 312 and / or heating by microwave 316 so as to transport the carrier 352 into and out of the thermalization and microwave heating zones 312, 316, as shown generally by arrows 396a and 396b. Unlike the embodiment illustrated in Figure 4c, the automatic transfer system 380 shown in Figure 4d is primarily disposed within the pressure adjustment zone 314a and is configured to extend out of and retract back to the adjustment zone Pressure 314a.

[0047] Regardless of the specific configuration of the transfer devices used by the automatic article transfer system 10, the transfer system can be automated, or controlled, by an automatic control system 390, as illustrated in the Figures. 4a and 4b. Although not specifically represented in the embodiments illustrated in Figures 4c and 4d, it should be understood that said control systems 390 can also be used in these embodiments. The automatic control system 390 can be used to control the movement and / or timing of at least one of the first and second balanced valves 330, 336, of the first and second gate valves 332, 338, and of the first and second transfer device 381, 382 of the automatic article transfer system 380. In one embodiment, the control system 390 may adjust the position, speed and / or timing of these devices or elements to ensure that the carriers within the system are move in a continuous and constant way.

 twenty

[0048] Turning now to Figures 5a-5d, an embodiment of a closing gate device 420 is provided, suitable for use as a gate device 332 and / or 338 in the microwave system portion 310 illustrated in Figures 4a and 4b. The closing gate valve device 420 is illustrated in Figures 5a-d generally comprising a pair of fixed elements spaced apart from each other 410, 412 having opposite sealing surfaces 414a, b and defining a gate receiving space 416 between them. Each of the fixed elements separated 25 from each other 410, 412 can define a flow opening 418a, b, which is limited by one of the sealing surfaces 414a, b. Each of the flow openings 418a, b is substantially aligned with each other so that the articles can pass through the cumulative opening when the gate valve device 420 is open.

 30

[0049] The closing gate device 420 further comprises a gate assembly 422, which is configured to be received within the gate receiving space 416 and which can be moved therein between a closed position (as shown in the Figures 5b and 5c), in which the gate assembly 422 substantially blocks the flow openings 418a, b, and an open position (as shown in Figure 5a), wherein the gate assembly 422 does not substantially block the opening of flow 418a, b. In one embodiment, the gate assembly 422 comprises a pair of sealing plates spaced apart from each other 424, 426 and a drive element 428 disposed between the seal plates 424, 426. When the gate assembly 422 is configured in the position closed, the drive element 428 is movable, with respect to the sealing plates 424, 426, between a retracted position (as shown in Figure 5b) and an extended position (as shown in Figure 5c). In an embodiment shown in 5a-c, the gate assembly 422 comprises at least one pair of bearings 430 40 disposed within the defined space between opposite sealing plates 424, 426, which is located in the gate receiving space 416 when the gate assembly 422 is in a closed position, as shown particularly in Figures 5b and 5c. When the drive element 428 moves between a retracted position, as illustrated in Figure 5b, to an extended position, as shown in Figure 5c, at least one pair 430 bearing can force at least one of the plates sealing 424, 426 outward, both moving away from each other 45 and towards a sealing position, as shown in Figure 5c.

[0050] In one embodiment, one or more of the bearings of the pair 430 may be secured, secured or at least partially housed within at least one of the sealing plates 424, 426 and / or drive element 428. According to one embodiment At least one of the bearings 430a can be fixedly fixed to the drive element 428, as shown in the enlarged partial view of the gate assembly 422 provided in Figure 5d. As the drive element 428 moves down in the gate receiving space 416, one of the pair bearings 430a may come into contact with one of the sealing plates 424, 426 (shown as plate 426 in Figure 5d ) and can move along a ramp (or slot) 427 of them. As the bearing travels through the groove 427 (or along the ramp 427), an outward pressure is exerted on the sealing plate 426, thereby moving it in a direction as indicated by arrow 460. Although shown as including a single pair of bearings 430, it should be understood that any number of bearings, positioned along the vertical length of the drive element 428 and / or sealing elements 424, 426, can be used.

[0051] When in a sealing position, as shown in Figure 5c, at least a portion of the sealing plates 424, 426 physically attaches or contacts the respective of the opposite sealing surfaces 414a, b, so as to form a substantially fluid tight seal. In one embodiment, each of the sealing plates 424, 426 comprises an elastic seal 423, 425 for coupling the sealing surfaces 414a, b when the sealing plates 424, 426 are in the sealing position. When the drive element 428 moves from the extended position, as shown in Figure 5c, back to the retracted position, as shown in Figure 5b, the sealing plates 424, 426 retract towards each other to the unsealed position, as shown in Figure 5b. In the non-sealing position, the sealing plates 424, 426 are decoupled from the opposite sealing surfaces 414a, b, but can be kept arranged within the gate receiving space 416. In one embodiment, the sealing plates 424, 426 they can be diverted to the unsealed position and can include at least one bypass device 429 (for example, a spring or springs) to deflect the sealing plates 424, 426 to the unsealed position.

[0052] Referring again to Figures 1a and 1b, the articles leaving the thermalization zone 12, and optionally passing through the pressure adjustment zone 14a, as described, can then be introduced into the zone microwave heating 16. In the microwave heating zone 16, the items can be quickly heated with a heat source that uses microwave energy. As used herein, the term "microwave energy" refers to electromagnetic energy with a frequency between 300 MHz and 30 GHz. In one embodiment, various microwave heating zone configurations 16 can use microwave energy with a frequency of about 915 MHz or a frequency of about 2.45 GHz, both having been designated as industrial microwave frequencies. In addition to microwave energy, the microwave heating zone 16 may optionally use one or more heat sources such as, for example, conductive or convective heating or other conventional heating methods or devices. However, at least 85 percent, at least 90 percent, at least 95 percent, or substantially all of the energy used to heat the items within the microwave heating zone 16 may be microwave energy of one microwave source. 25

[0053] According to one embodiment, the microwave heating zone 16 can be configured to increase the temperature of the items above a minimum threshold temperature. In an embodiment in which the microwave system 10 is configured to sterilize multiple items, the minimum threshold temperature (and the minimum operating temperature of the microwave heating zone 16) can be at least about 120 ° C, at least about 121 30 ° C, at least about 122 ° C and / or no more than about 130 ° C, no more than about 128 ° C, or no more than about 126 ° C. The microwave heating zone 16 may operate at approximately ambient pressure, or it may include one or more pressurized microwave chambers operating at a pressure of at least about 5 psig, of at least about 10 psig, of at least about 15 psig, and / or no more than about 80 psig, no more than about 60 psig, or no more than about 40 psig. In one embodiment, the pressurized microwave chamber can be a liquid-filled chamber with a working pressure such that the items being heated can reach a temperature above the normal boiling point of the liquid medium employed therein.

[0054] The articles passing through the microwave heating zone 16 can be heated to the desired temperature in a relatively short period which, in some cases, can minimize damage or degradation of the articles. In one embodiment, the articles that pass through the microwave heating zone 16 may have an average residence time of at least about 5 seconds, at least about 20 seconds, of at least about 60 seconds and / or not more than about 10 minutes, no more than about 8 minutes, or no more than about 5 minutes. In the same or other embodiments, the microwave heating zone 16 can be configured to increase the average temperature of the items being heated by at least about 20 ° C, 45 by at least about 30 ° C, at least about 40 ° C, at least about 50 ° C, at least about 75 ° C and / or no more than about 150 ° C, no more than about 125 ° C, or no more than about 100 ° C, at a speed heating at least about 15 ° C per minute (° C / min), at least about 25 ° C / min, at least about 35 ° C / min and / or no more than about 75 ° C / min, not more than about 50 ° C / min, or no more than about 40 ° C / min.

 fifty

[0055] Turning now to Figure 6a, an embodiment of a microwave heating zone 516 is illustrated as generally comprising a microwave heating chamber 520, at least one microwave generator 512 for generating microwave energy and a system of microwave distribution 514 to direct at least a portion of the microwave energy from the generator 512 to the microwave chamber 520. The microwave distribution system 514 comprises multiple waveguide segments 518 and one or more 55 microwave launchers, shown as launchers 522a-f in Figure 6a, for discharging microwave energy inside the microwave chamber 520. As shown in Figure 6a, the microwave heating zone 516 may further comprise a conveyor system 540 for transporting 550 items to be heated through the microwave chamber 520. Each of the components of the product is immediately discussed in detail. to heating zone by

microwave 516 according to various embodiments of the present invention.

[0056] Microwave generator 512 may be any device suitable for generating microwave energy of a desired wavelength (λ). Examples of suitable types of microwave generators may include, but are not limited to, magnetrons, klistrons, progressive wave tubes, and girotrons. Although illustrated in Figure 6a 5 as including a single generator 512, it should be understood that the microwave heating system 516 can include any number of generators arranged in any suitable configuration. For example, in one embodiment, the microwave heating zone 516 may include at least 1, at least 2, at least 3 and / or no more than 5, no more than 4, or no more than 3 microwave generators, depending of the size and arrangement of the 514 microwave distribution system. Specific embodiments of a microwave heating zone that includes multiple generators will be discussed in detail below.

[0057] The 520 microwave chamber can be any chamber or container configured to receive multiple items. The microwave chamber 520 can be any size and can have one of a variety of different shapes in section. For example, in one embodiment, the chamber 520 may have a generally circular or elliptical cross section 15, while, in other embodiments, it may have a generally square, rectangular or polygonal cross-sectional shape. In one embodiment, the microwave chamber 520 may be a pressurized chamber and, in the same or other embodiments, may be configured to be filled at least partially with a liquid medium (a liquid filled chamber). The microwave chamber 520 may also be configured to receive at least a portion of the microwave energy discharged from one or more microwave launchers 20 522 and, in one embodiment, may be configured to allow the formation of a stable wave model ( or stationary) in it. In one embodiment, at least one dimension of the microwave chamber 520 may be at least about 0.30λ, at least about 0.40λ, or at least about 0.50λ, where λ is the wavelength of the microwave energy discharged into it.

 25

[0058] The microwave distribution system 514 comprises multiple waveguides or waveguide segments 518 to direct at least a portion of the microwave energy from the generator 512 to the microwave chamber 520. The waveguides 518 may be designed and constructed to propagate microwave energy in a predominantly specific manner, which may be the same or different than the microwave energy mode generated by generator 512. As used herein, the term "mode" refers to a cross-sectional field model 30 Generally fixed microwave energy. In one embodiment of the present invention, waveguides 518 can be configured to propagate microwave energy in a TExy mode, where x and y are integers within the range of 0 to 5. In another embodiment of the present invention, waveguides 518 can be configured to propagate microwave energy in a TMab mode, where a and b are integers within the range of 0 to 5. It should be understood that, as used herein, the previously defined ranges of values a, b, x, e and as used for Describe a microwave propagation mode are applicable throughout this description. In one embodiment, the predominant mode of microwave energy propagated through waveguides 518 and / or discharged by launchers 522a-f can be selected from the group consisting of TE10, TM01, and TE11.

[0059] As shown in Figure 6a, a microwave distribution system 514 further comprises one or more 40 microwave launchers 522a-f, each defining at least one launch opening 524a-f for discharging microwave energy into a microwave chamber 520. Although illustrated in Figure 6a as including six microwave launchers 522a-f, it should be understood that the microwave distribution system 514 can include any number of launchers arranged in any desirable configuration. For example, a microwave distribution system 514 may include at least 1, at least 2, at least 3, at least 4 and / or no more than 50, no more than 45 of 30 or no more than 20 microwave launchers. The 522a-f launchers may be of the same or different types of launchers and, in one embodiment, at least one of the 522a-f launchers may be replaced by a reflecting surface (not shown) to reflect at least a portion of the energy of microwave discharged from the other 522 launchers in the 520 microwave heating chamber.

 fifty

[0060] When the microwave distribution system 514 includes two or more launchers, at least some of the launchers may generally be arranged on the same side of the microwave chamber 520. As used herein, the words "launchers thereof. "side" refers to two or more launchers generally located on the same side of a microwave chamber. Two or more pitchers on the same side may also be axially separated from each other. As used herein, the term "axially separated" refers to spacing in the direction of transport 55 of the articles through the microwave system (ie spacing in the direction of extension of the transport axis). In addition, one or more launchers 522 may also be laterally separated from one or other launchers 522 of the system. As used herein, the term "laterally separated" refers to spacing in the direction perpendicular to the direction of transport of the articles through the microwave system (ie,

spacing perpendicular to the direction of extension of the transport axis). For example, in Figure 6a, launchers 522a-c and 522d-f are arranged on respective first and second sides 521a, b of microwave chamber 520 and launcher 522a is axially separated from launcher 522b and 522c, just like the pitcher 522e is axially separated from pitchers 522f and 522d.

 5

[0061] In addition, as shown in the embodiment depicted in Figure 6a, the microwave distribution system 514 may comprise at least two (eg, two or more) pairs of pitchers arranged opposite or opposite. As used herein, the term "opposing launchers" refers to two or more launchers located on generally opposite sides of a microwave chamber. In one embodiment, opposing pitchers may be facing each other. As used herein with respect to opposing microwave launchers, the term "faced" 10 will denote launchers whose central launch axes are substantially aligned with each other. For simplicity, the central launching axis 523c of launcher 522c and the central launching axis 523d of launcher 522d are the only central launching axes illustrated in Figure 6a. However, it should be understood that each of the 522a-f launchers includes similar launch axes.

 fifteen

[0062] Opposite pitchers may be generally aligned with each other, or they may be offset with respect to one or more different pitchers arranged on the opposite side of the microwave chamber 520. In one embodiment, a pair of opposing pitchers may be a pair of three-pitch pitchers, so that the discharge openings 524 of the pitchers 522 are not completely aligned with each other. The 522th and 522e pitchers constitute an exemplary pair of opposing pitchers arranged in a bent configuration. Opposite pitchers 20 can be offset axially or laterally. As used herein with respect to opposing microwave launchers, the term "axially offset" refers to launchers whose central launch axes are axially spaced from each other. As used herein with respect to opposing microwave launchers, the term "laterally staggered" refers to launchers whose central launching axes are spaced laterally from each other. In another embodiment, a pair of opposing pitchers can be directly opposite pitchers, so that the discharge openings of the pair of pitchers are substantially aligned. For example, launchers 522c and 522d shown in Figure 6a are configured as a pair of opposing pitchers.

[0063] In some embodiments, microwave heating zone 516 may include two or more transport lines operating simultaneously with each other. An exemplary multi-line conveyor system 540 is shown in Figures 6b and 6c. As shown in Figures 6b and 6c, the conveyor system 540 may be configured to transport multiple items 550 in a transport direction generally represented by arrow 560 in Figure 6b. In one embodiment, the conveyor system 540 may include at least two substantially parallel and laterally separated transport lines, such as, for example, first, second and third transport lines 542a-c shown in Figure 6b. The transport lines 542a-c may, in one embodiment, comprise individual conveyor systems, while, in another embodiment each of the transport lines 542a-c may be parts of a complete conveyor system. The conveyor system 540 and / or the transport lines 542a-c may be any type of conveyor or suitable conveyor system, including those discussed previously in detail. 40

[0064] The microwave heating system 516 depicted in Figures 6b and 6c includes multiple microwave launchers 522 that can be divided or organized into at least two groups of two or more microwave launchers. Each of the first, second and third transport lines 542a-c can be configured to receive microwave energy from respective first, second and third groups of microwave launchers. In one embodiment, a "group" of launchers may refer to one or more axially spaced launchers, generally positioned along the transport direction (for example, the launcher group 522a-d, the launcher group 522e -h, and / or the group of launchers 522i-l shown in Figure 6b), while, in the other embodiment, a group of launchers may include one or more pairs of opposing launchers located on different sides of a microwave chamber ( for example, groups that include a pair of pitchers 522a and 522m, the group that includes a pair of 50 pitchers 522b and 522n, a group that includes a pair of pitchers 522c and 522o, and a group that includes a pair of pitchers 522d and 522p, as shown in Figure 6c). When the pitcher group comprises one or more pairs of opposing pitchers, the pitchers may be arranged in a three-way configuration (not shown) or they may be directly opposite each other (e.g., facing each other), as illustrated in Figure 6c . According to one embodiment, at least one generator, shown as generator 512a in Figure 6b can be configured to supply microwave power to at least one group of microwave launchers.

[0065] As shown particularly in Figure 6b, individual microwave launchers 522 of adjacent transport lines 542 may be arranged in a three-way configuration with each other in the direction of

transport. In one embodiment, one or more microwave launchers on the same side 522a-1 may be axially offset from each other. For example, in the embodiment shown in Figure 6b, launchers 522a-d associated with the first transport line 542a are arranged in a stripped configuration with respect to each of the respective launchers 522e-h associated with the second transport line. 542b with respect to and / or along the transport direction 560. As used herein with respect to microwave launchers on the same side, the term 5 "axially offset" will denote launchers that are axially separated from each other by a distance greater than 1/2 of the maximum axial dimension of the launcher launch openings. As used herein with respect to microwave launchers on the same side, the term "laterally offset" will denote launchers that are spaced laterally from each other over a distance greater than 1/2 of the maximum lateral dimension of the launch openings. of pitchers. 10

[0066] In addition, in the same or another embodiment, the microwave launchers associated with the non-adjacent transport lines (eg, the first and third transport lines 542a, c) may be arranged in substantially aligned configurations with each other, such as It is illustrated in the 522a-d launcher arrangements with respect to the 522i-I launchers shown in Figure 6b. Alternatively, at least a portion of the launchers 522i-l 15 associated with the third transport line 542c may be offset relative to the launchers 522a-d of the first transport line 542a and / or second transport line 542b (embodiment not shown ). Although generally shown in Figure 6b as including little or no space between adjacent transport line launchers, it should be understood that, in one embodiment, there may be some space between adjacent line launchers (e.g., 522a and 522e launchers, launchers 522b and 522f, etc.). In addition, individual launchers 522 20 may have any suitable design or configuration and, in one embodiment, may include at least one feature of one or more embodiments of the present invention that will be described in detail herein.

[0067] Turning now to Figure 7a, a partial view of an embodiment of a microwave heating zone 616 is shown. The microwave heating zone 616 includes at least one microwave launcher 622 25 defining a launch opening 624 for discharging energy in a microwave chamber 620. As shown in Figure 7a, microwave launcher 622 is configured to discharge microwave energy along a central launch axis 660 towards a conveyor system 640 configured to transport multiple items. 650 within the microwave chamber 620 along a transport axis 642. In one embodiment, the central launch axis 660 may be inclined so that an inclined angle of launch, β, is defined between the central axis of launch 660 and a normal plane to the transport axis 642, illustrated as plane 662 in Figure 7a. According to one embodiment, the pitching angle β may be at least about 2 °, at least about 4 °, at least about 5 ° and / or not more than about 15 °, not more than about 10 °, or not more of about 8º.

[0068] Turning now to Figure 7b, another embodiment of a microwave heating system 616 35 is shown including two or more launchers 622a-c, each configured to discharge energy into microwave chamber 620 along the respective 660a-c inclined center launch shafts. In one embodiment in which the microwave heating system 616 includes two or more inclined pitchers, the central throwing axes of the pitchers, especially the pitchers on the same side, can be substantially parallel to each other, as generally illustrated by the axes. Launch centers 660a, b of launchers 622a, b shown in Figure 7b. As used herein, the term "substantially parallel" means within 5º of the parallelism. In the same or another embodiment, the central launching axes of two or more launchers, especially opposing launchers, within the microwave heating zone 616 may be substantially parallel or substantially aligned, as illustrated in launch axes 660a, c of microwave launchers 622a, c in Figure 7b. When the microwave heating zone 616 comprises n inclined microwave launchers having oriented central launching axes 45 as described above, each launcher can define a respective launch inclination angle βn, within the ranges described above. In one embodiment, each of the pitching angles βn of each pitcher may be substantially the same, while, in another embodiment, at least one of the pitching angles of launching βn can be substantially different from one or more of the other angles of inclination of launch. fifty

[0069] With reference again to Figure 6a, at least one of the launching openings 524a-f of the launchers 522a-f of the microwave system 516 may be at least partially covered by a substantially transparent microwave window 526a-f arranged between each launch opening 524a-f and the microwave chamber 520. The transparent microwave windows 526a-f can function to prevent fluid flow between the microwave chamber 520 and the microwave launchers 522a-fa while allowing a Substantial portion of the microwave energy of the 522a-f launchers pass through it. The 526a-f windows may be made of any suitable material, which includes, but is not limited to, one or more thermoplastic materials or glass such as Teflon with fiberglass filling, polytetrafluoroethylene (PTFE), polymethylmethacrylate (PMMA), polyetherimide ( PEI), oxide

of aluminum, glass, and combinations thereof. In one embodiment, the windows 526a-f may have an average thickness of at least about 4 mm, of at least about 6 mm, of at least about 8 mm and / or of no more than about 20 mm, of no more than about 16 mm, or no more than about 12 mm and can withstand a pressure difference of at least about 40 psi, of at least about 50 psi, of at least about 75 psi and / or of no more than about 200 psi, of no more than about 150 psi, or no more than about 120 psi without breaking, cracking or otherwise breaking down. 5

[0070] Several embodiments of configurations suitable for microwave launcher windows are shown in Figures 8a-c. As shown in Figures 8a-c, each of the microwave windows 726 defines a surface of the chamber side 725 that can optionally define at least a part of the side wall 721 of the microwave chamber 720. According to an embodiment shown in Figure 1, the surface of the camera side 10 725 of the window 726 can be configured so that at least 50 percent, at least 65 percent, at least 75 percent, at least 85 percent , or at least 95 percent of the total surface area of the side of the chamber 725 is oriented at an angle of inclination, α, from the horizontal. The angle of inclination α may be at least about 2 °, at least about 4 °, at least about 8, at least about 10 ° and / or not more than about 45 °, of not more than about 30 °, or not more than about 15 ° from the horizontal, illustrated as a dotted line 762. In other 15 embodiments, the angle of inclination, α, may also be defined between the elongation axis 762 of the microwave chamber 720 and / or a transport axis (not shown in Figures 8a-c) when, for example, these axes are parallel to the horizontal.

[0071] The surface of the chamber side 725 of the window 726 may be oriented from the horizontal 20 regardless of whether the launcher 722 is oriented with a pitching angle, as described above or not. In one embodiment, the window 726 may be substantially flat and inclined from the horizontal (as shown in Figure 8a), while, in the same or another embodiment, the surface of the chamber side 725 of the window 726 may include a or more convexities (as shown in Figure 8b) or concavities (as shown in Figure 8c). When the surface of the chamber side 725 is not substantially flat, one or more (or n) total inclined angles can be formed as described above. Depending on the exact configuration of the surface of the chamber side 725, the multiple angles of inclination formed by it may be the same or different from other angles of inclination formed by the same surface 725.

[0072] As previously discussed, the microwave launchers 522a-f shown in Figure 6a may have any suitable configuration. Several views of a microwave launcher 822 configured according to an embodiment of the present invention are provided in Figures 9a-f. With reference initially to Figure 9a, microwave launcher 822 is illustrated as comprising a set of opposite side walls 832a, by a set of opposite end walls 834a, b, which collectively define a substantially rectangular launch opening 838. When the opening Launch 838 comprises a rectangular shaped opening, it can have a width (W1) and a depth (D1) defined, at least in part, by the terminal edges of the side walls 832a, b and 834a, b, respectively. In one embodiment, the side walls 832a, b may be wider than the end walls 834a, b, so that the length of the lower end edge of the side walls 832a, b, shown as W1 in Figure 9a, may be greater that the length of the lower terminal edge of the end walls 834a, b, shown in Figure 9a with the identifier D1. As shown in Figure 9a, the elongated portion 40 of the side walls 832a, b and the end walls 834a, b can also collectively define a path 837 through which microwave energy can be propagated as it passes from the entrance of microwave 836 to the at least one launch opening 838 defined by launcher 822.

[0073] When used to discharge microwave energy in a microwave chamber, the opening of launch 838 may be lengthened in the direction of extension of the microwave chamber

[0074] (not shown) or at the transport address of the items therein. For example, in one embodiment, the side walls 832a, b and the end walls 834a, b of the launcher 822 can be configured so that the maximum dimension of the release opening 838 (shown in Figure 9a as W1) can be aligned substantially parallel. to the extension address of the microwave chamber and / or to the transport address of the items that pass through it. In this embodiment, the terminal edges of the side walls 832a, b may be oriented parallel to the extension direction (or the transport direction), while the end edges of the end walls 843a, b may be aligned substantially perpendicular to the direction extension or transport inside the microwave chamber (not shown in Figure 9). 55

[0075] Figures 9b and 9c respectively provide views of a side wall 832 and an end wall 834 of the microwave launcher 822 illustrated in Figure 9a. It should be understood that, while only one of the side or end walls 832, 834 is shown in Figures 9b and 9c, the other of the pair may have a similar configuration. In a

embodiment, at least one of the side wall 832 and the end wall 834 can be flared so that the input dimension (width W0 or depth D0) is smaller than the output dimension (width W1 or depth D1), as illustrated respectively in Figures 9b and 9c. When camping, each of the side and end walls 832, 834 defines respective angles of width and depth of camping, θw and θd, as shown in Figures 9b and 9c. In one embodiment, the width and / or depth angles of 5 camping θw and / or θd can be at least about 2 °, at least about 5 °, at least about 10 °, or at least about 15 ° and / or of no more than about 45 °, no more than about 30 °, or no more than about 15 °. In one embodiment, the width and / or depth of camping angles θw and θd may be the same, while in another embodiment, the values of θw and θd may be different.

 10

[0076] According to one embodiment, the camping depth angle θd may be smaller than the camping width angle θw. In some embodiments, the camping depth angle θd may be no more than about 0 °, so that the inlet depth D0 and the output dimension D1 of the microwave launcher 822 are substantially the same, as illustrated in the embodiment illustrated in Figure 9d. In another embodiment, the camping depth angle θd may be less than 0 °, so that D1 is less than 15 D0, as shown in Figure 9e. When the launcher 822 comprises a camping depth angle of less than 0 ° and / or the depth D1 of the launching opening 838 is less than the depth D0 of the microwave inlet 836, the microwave launcher 822 can be a conical caster which presents a generally inverse profile. In an embodiment where the microwave launcher 822 comprises n launch openings, between 1 and n of the openings may have a depth and / or width less than or equal to the depth and / or width of the entrance of the launcher. Additional embodiments of multi-aperture launchers are described in detail below.

[0077] According to an embodiment of the present invention, the depth D1 of the release opening 838 may be no more than about 0.625 λ, no more than about 0.5 λ, no more than about 0.4 λ, of no more than about 0.35 λ, or not 25 no more than about 0.25 λ, where λ is the wavelength of the predominant mode of microwave energy discharged from the launching opening 838. Although not wishing Being conditioned by the theory, it is believed that by minimizing the depth D1 of the launching opening 838, the microwave field created close to the launching opening 838 is more stable and uniform than that which would be created with launchers having greater depths. In one embodiment in which the microwave launcher 822 comprises n launch openings, the depth of each launch opening, dn, may be no greater than about 0.625 λ, no greater than about 0.5 λ, no greater than about 0 , 4 λ, not greater than about 0.35 λ, or not greater than about 0.25 λ. When microwave launcher 882 has multiple openings, each opening may have a depth that is the same or different than one or more of the other launch openings of the same launcher.

 35

[0078] Referring now to Figures 10a-c., Another embodiment of a microwave launcher 922 suitable for use in microwave heating systems described herein is illustrated as comprising a single microwave input 936 and two or more launch openings , which are shown as launch or download openings 938a-c, to discharge microwave energy from them. The microwave launcher 922 illustrated in Figures 10a-c includes first, second, and third separate launch openings 938 a-c, which are spaced 40 laterally from each other. Although described herein as defining three launch openings, it should be understood that launcher 922 may include any suitable amount of launch openings, including at least 2, at least 3, at least 4 and / or no more than 10 , no more than 8, or no more than 6. The spacing between each first, second and third launch openings 938a-c may be at least about 0.05 λ, at least about 0.075 λ, or at least about 0.10 λ and / or no more than about 0.25 λ, no more than about 0.15 λ, or no more than about 0.1 λ, where λ is the 45 wavelength of the predominant energy mode Microwave downloaded from launcher 922.

[0079] In one embodiment, each of the first, second and third launch openings is separated by one or more partition walls 940a, b disposed within the interior of the launcher 922, as shown in Figures 10a-c. The partitions 940a, b normally have a thickness equal to the desired separation between the discharge openings 50 938a-c. When the microwave launcher comprises n partitions, microwave launcher 922 defines (n + 1) separate launch openings and (n + 1) separate microwave paths 937a-c defined between microwave input 836 and each launch opening 938a -c, as shown particularly in Figure 10c. As shown in Figure 10c, each of the microwave paths 937a-c has a length, L1-L3, which extends from the inlet 936 to a perpendicular point with the respective launch opening 938a-c. Each L1-L3 may be substantially the same, or at least one of the L1, L2, and L3 may be substantially different. According to one embodiment, particularly shown in Figure 10c, one or more paths 937a-c may be longer than one or more different paths 937a-c.

[0080] When one or more paths 937a-c are of different lengths than one or more different paths, the dimensions (L1, L2, and / or L3) of the paths 937a-c may be adjusted so that the phase velocity of the microwave energy that propagates through it accelerates at a faster rate within the longer microwave paths (for example, L1 and L3 in Figure 10c) than through the shorter paths (for example, L2 in Figure 10c). While the theory is not intended to condition, the hypothetical case is that such adjustment can be carried out to ensure uniform synchronization of the individual wave portions, thus creating a uniform wavefront as the microwave energy is discharge into chamber 520. When microwave launcher 922 includes a single partition, only two microwave paths are created (the embodiment is not shown) and the length of each path is substantially the same. Therefore, little or no control of the phase velocity of microwave energy passing through paths of equal length may be necessary. 10

[0081] In the same or another embodiment, each of the launching openings 938a-c may define a depth, d1-3, as generally shown in Figure 10b. In one embodiment, each of the depths of d1 to d3 may be substantially equal, while, in another embodiment, at least one of the depths d1-d3 may be different. As discussed earlier, one or more of the d1-d3 may be no more than about 0.625λ, no more than 15 about 0.5λ, no more than about 0.4λ, no more than about 0.35λ, or no more of about 0.25λ, where λ is the wavelength of the predominant microwave energy mode discharged from the launch opening 938a-c. In addition, in one embodiment, at least one of the dimensions d1-d3 may be less than or equal to the depth d0 of the inlet 936, as previously described in detail. As shown in Figure 10b, the depths, d1-3, of each of the launch openings 938a-c do not include the thickness of the partitions 940a, b, when present. twenty

[0082] Again with reference to Figures 6a, in one embodiment, the microwave distribution system 514 of the microwave heating zone 516 may include at least one microwave distribution device 525a, b for allocating or distributing energy from microwave in chamber 520 using multiple 522a-c and 522d-f launchers. In one embodiment, the microwave distribution manifold 525a, b may include at least three microwave allocation devices 25 configured to divide the microwave energy of generator 512 into two or more separate portions before being discharged from at least one of the launchers of microwave 522a-f. As used herein, the term "microwave allocation device" refers to any device or article that functions to divide microwave energy into two or more separate portions, according to a predetermined relationship. As used herein, the term "predetermined energy ratio" refers to the ratio of the amount of energy of each resulting separate portion 30 that comes out of a specific microwave allocation device. For example, a microwave allocation device configured to divide the energy that passes through it at a 1: 1 energy ratio would be configured to divide the power that is introduced into it into two substantially equal portions.

[0083] However, in one embodiment of the present invention, at least one of the microwave assignment devices, shown as inductive iris 570a-h and T-shaped or splitter or two-way 572 in Figure 6a, of the 514 microwave distribution system may be configured to have a predetermined power ratio other than 1: 1. For example, one or more microwave assignment devices 570ah or 572 may be configured to divide the microwave energy that passes through it according to a predetermined energy ratio of at least about 1: 1.5, of at least about 1: 2, at least about 1: 3 and / or no more than about 1:10, no more than about 1: 8, or no more than about 1: 6.

[0084] Each of the 570a2-h and / or 5 allocation devices used by the 514 microwave distribution system can be configured to discharge energy according to the same ratio, or one or more 570a-h allocation devices can be configured with a ratio of different power. The allocation devices 570a-h and 572 may be configured so that substantially the same amount of power is discharged from each of the launchers 522a-f, while, in another embodiment, the allocation devices 570a-h and 572 may be designed collectively to divert and unload more power from one or more 522a-f launchers, discharging less power through the rest of the 522a-f launchers. The specific power ratios used by each of the 570a-h and 572 microwave allocation devices, as well as the model or general configuration of the microwave energy allocation within the system, may depend on a variety of factors including, for example, the type of items being heated, the desired operating conditions of the microwave heating zone 516, and other similar factors.

[0085] In practice, an initial amount of microwave energy can be introduced into the microwave distribution system 514 and can be divided into two portions when it passes through divider 572. In one embodiment, the two portions of microwave energy leaving the divider 572 may be approximately the same power, while, in another embodiment, one of the two portions may have more power than the other. As shown in Figure 6a, each portion can pass to a respective manifold 525a, b, optionally passing through the device

phase change 530 before entering collector 525a, b. Described now with respect to the microwave distribution manifold 525a, it should be understood that an operation analogous to a bottom manifold 525b shown in Figure 6a is applicable.

[0086] The microwave power exiting the divider 572 and, optionally, the phase change device 530 5 (embodiments that will be described in detail below) can then pass through a microwave allocation device, shown like iris 570a, where the power can be divided into a first fraction of microwave launch and a first fraction of microwave distribution. The first launch microwave fraction can be directed towards launcher 522a and can be discharged by output 524a. The first distribution microwave fraction can be propagated down the waveguide 518 to 10 additional microwave launchers 522b, c. According to one embodiment, the power ratio of the first launch microwave fraction with respect to the first distribution microwave fraction leaving the iris 570a may be not greater than about 1: 1, not greater than about 0.95: 1, no greater than about 0.90: 1, no greater than about 0.80: 1, no greater than about 0.70: 1 or no greater than about 0.60: 1. In one embodiment, the power ratio of the first launch microwave fraction with respect to the first distribution microwave fraction is not 1: 1. fifteen

[0087] When the first distribution microwave fraction is propagated to launchers 522b, it can then be divided into a second launch microwave fraction directed towards launcher 522b that will be unloaded by launch output 524b, and a second fraction of distribution microwave that propagates down the waveguide 518 towards launcher 522c. In one embodiment, the ratio of the second launch microwave fraction to the second distribution microwave fraction may be at least about 0.80: 1, at least about 0.90: 1, at least about 0.95 : 1 and / or no more than about 1.2: 1, no more than about 1.1: 1, no more than about 1.05: 1, or it can be about 1: 1. Subsequently, the rest of the microwave energy (for example, the entire second distribution microwave fraction) can then be directed to the final microwave launcher 522c and discharged from launch output 524c. 25

[0088] According to another embodiment (not shown in Figure 6a), the microwave distribution system 514 may include a microwave distribution manifold 525a, b having more than three launchers. For example, when the microwave distribution manifold 525 includes n launchers, all stages except the dividing stage (n-1) can be carried out so that the ratio of the launch microwave fraction to the fraction of 30 microwave distribution is not 1: 1. For each of the stages, except stage (n-1), the power ratio may be no greater than about 1: 1, no greater than about 0.95: 1, no greater than about 0.90: 1, not greater than about 0.80: 1, not greater than about 0.70: 1 or not greater than about 0.60: 1, while the division stage (n-1) can be carried out so that the ratio from the launch microwave fraction to the second distribution microwave fraction can be at least about 0.80: 1, at least about 0.90: 1, at least about 0.95: 1 and / or no more than about 1.2: 1, 35 no more than about 1.1: 1, no more than about 1.05: 1, or it can be about 1: 1. The distribution microwave fraction (n-1) can then be sent, mostly or in its entirety, as a launch microwave fraction n to be unloaded into the microwave chamber by the microwave launcher n.

[0089] In addition to one or more iris 570a-h positioned within the microwave distribution system 514, one or 40 more launchers 522 may also include at least one inductive iris disposed within the launcher, as shown in an embodiment illustrated in the Figures 11a and 11b. Alternatively, one or more irises 570b and / or 570d may be arranged within the launchers 522a and / or 522b, respectively, instead of being arranged within a waveguide as shown in Figure 6a.

 Four. Five

[0090] An embodiment of a microwave launcher 1022 including an inductive iris disposed therein is shown in Figure 11a. Launcher 1022 may include at least one inductive iris 1070 located between its microwave inlet 1036 and one or more launch openings 1038, as generally illustrated in Figures 11a and 11b. As shown in Figures 11a and 11b, the iris 1070 can be defined by a pair of inductive iris panels 1072a, b arranged on opposite sides of the launcher 1022. Although they are shown as coupled to opposite end walls plus narrow 50s 1034a, b of the launcher 1022, it should be understood that the first and second iris panels 1072a, b may also be coupled to opposite side walls 1032a, b wider than the launcher 1022 As shown in Figures 11a and 11b, the first and second iris panel 1072a , b extend inward in the microwave path 1037 defined between the microwave inlet 1036 and the launch opening 1038 in a direction that is generally transverse to the direction of microwave propagation through the path 1037. In one embodiment, Iris 55 panels obstruct at least 25 percent, at least 40 percent, or at least 50 percent and / or no more than 75 percent, no more than 60 percent, or no more than a 5 5 percent of the total microwave path area 1037 in the situation in which they are arranged. When microwave launcher 1022 comprises two or more launch openings, as shown in Figure 11c, the first and second iris panels 1072a, b may be

configured to obstruct at least a portion of each of the launching openings 1038a-c of the launcher 1022.

[0091] As shown in Figure 11a, the first and second iris panels 1072a, b may be substantially coplanar and may be substantially normal to the central axis of launch of microwave launcher 1022. In some embodiments, the iris panels 1072a, b may be separated from both microwave input 1036 and launch opening 1038 of microwave launcher 1022. For example, iris panels 1072a, b may be separated from microwave input 1036 of launcher 1022 in at least 10 percent, at least 25 percent, or at least 35 percent of the minimum distance between microwave input 1036 and launch opening 1038 of launcher 1022. In addition, iris panels 1072a, b they can be separated from the launch opening 1038 of the launcher 1022 by at least 10 percent, 25 percent, or 35 percent of the maximum distance (L) measured between the microwave input 1036 and the opening d and release 1038 of launcher 1022.

[0092] Returning again to Figure 6a, the microwave distribution system 514 is illustrated as further comprising one or more devices or for increasing the uniformity and / or intensity of the microwave field created within the microwave heating chamber. 520. For example, in one embodiment, the microwave distribution system 514 may include one or more devices designed to modify and / or control the situation and intensity of the constructive interference bands of the microwave field created within each individual zone of heating 580a-c, which are respectively defined between pairs of pitchers 522a and 522f, 522b and 522e, and 522c and 522d. In one embodiment, said device may be a phase change device, schematically represented in Figure 6a as device 530, operable to cyclically change the phase of microwave energy passing through it.

[0093] As articles 550 move along conveyor system 540 within microwave chamber 520, each article 550 may have an average residence time (τ), within each individual heating zone 25 580a- c, of at least about 2 seconds, of at least about 10 seconds, of at least about 15 seconds and / or of no more than about 1 minute, no more than about 45 seconds, or no more than about 30 seconds. In one embodiment, the average residence time (τ) for articles 550 may be greater than the phase change speed (t) for which the phase change device 530 is configured. For example, the average time ratio The rate of phase change of the device 530 (τ: t) can be at least about 2: 1, at least about 3: 1, of permanence of the articles passing through one of the individual heating zones 30 580a-ca , at least about 4: 1, at least about 5: 1 and / or not more than about 12: 1, not more than about 10: 1, or not more than about 8: 1.

[0094] The phase change device 530 may be any device suitable for rapidly and cyclically displacing the microwave energy phase passing through the microwave distribution system 514. According to one embodiment, the phase switching device 530 it can be configured to shift the microwave energy that passes through it at a phase change rate (t) of at least about 1.5 cycles per second, at least about 1.75 cycles per second, or at less than 2.0 cycles per second and / or no more than about 10 cycles per second, no more than about 8 cycles per second, and / or no more than about 6 cycles per second. As used herein, the term "phase change rate" refers to the number of complete phase change cycles 40 completed per second. A "complete phase change cycle" refers to a phase change from 0 ° to 180 ° and again to 0 °. Although it is shown including a single phase change device 530, it should be understood that any suitable number of phase change devices can be used in the microwave distribution system 514.

 Four. Five

[0095] In one embodiment, the phase change device 530 may comprise a plunger-type tuning device capable of operating so that it moves in a generally linear manner (eg, up-down movement) within a cylinder so as to cause the phase of the microwave energy that passes through it is cyclically displaced. Figures 12a and 12b illustrate two embodiments of a piston tuning device 1130a, b suitable for use in a microwave distribution system 514. Figure 12a describes a phase change device of a single piston 1130a that includes a plunger 1132 operable to move within a single cylinder 1134 by an automatic actuator 1136. Figure 12b illustrates another embodiment of a phase change device comprising a multi-piston phase change device that includes a plurality of pistons 1132a-d arranged and operable to move within several corresponding cylinders 1134a-d. The pistons 1132a-d can be operated by a single automatic actuator 1136, which can be connected to each of the pistons 1132a-d by means of a rotating cam shaft 1138. Any of the piston-type tuning devices 1130a, b can be connected to a coupler, such as a short-slot hybrid coupler (not shown in Figures 12a and 12b) and can be used in a microwave distribution system 514 as a phase change device 530 as described before.

[0096] Another embodiment of a suitable phase change device is depicted in Figures 13a-e. In comparison to the phase change device or tuning devices illustrated in Figures 12a and 12b, the phase change devices illustrated in Figures 13a-e are rotating phase change devices. For example, as shown in Figures 13a-c, an embodiment of a rotating phase change device 1230, 5 also referred to as a variable phase short circuit, may comprise a fixed section 1210 defining a first substantially rectangular opening 1212 and a rotating section 1240 located next to said first opening 1212. As shown in Figure 13a, a clearance 1213 can be defined between the rotating section 1240 and the fixed section 1210 and, in one embodiment, a microwave choke (not shown) can be at least partially disposed within the space 1213 to prevent microwave energy leakage from the fixed and rotating sections 1210 and 1240.

[0097] The rotating section 1240 comprises a housing 1242 and multiple substantially parallel separate plates 1244a-d received within the housing 1242. As shown in Figure 13a, the housing 1242 comprises a first end 1243a and a second end 1243b and the first end 1243a defines a second opening 1246 adjacent to the first rectangular opening 1212 of the fixed section 1210. As indicated by arrows 1290, 1292 in Figure 13a, the rotating section 1240 can be configured to rotate about the fixed section 1210 around a rotation shaft 1211 extending through the first and second openings 1212, 1246, as shown generally in Figures 13a-c.

 twenty

[0098] As shown in particular in Figures 13b and 13c, housing 1242 has a length (LH), a width (WH), and a depth (DH). In one embodiment, at least one of LH, WH, and DH is about 0.5λ, about 0.65λ, about 0.75λ and / or no more than about 1λ, no more than about 0.9λ , or of no more than about 0.75λ, where λ is the wavelength of the microwave energy whose variable phase short circuit 1230 is configured to pass between the first and second openings 1212 and 1246. In one embodiment, at least one of the dimensions WH and DH is 25 at least about 0.5λ and both are not more than about λ. As shown generally in Figures 13a-c, the transverse shape of the housing 1242 is substantially square, so that the WH: DH ratio is not greater than about 1.5: 1, not greater than about 1.25: 1, or not greater than about 1.1: 1.

[0099] Fixed section 1210 may have any suitable shape or size and may comprise a circular or rectangular waveguide 30. In one embodiment shown in Figure 13d, the first substantially rectangular opening 1212 may have a width (WR) and a depth (DR) such that the ratio of WR: DR is at least about 1.1: 1, at minus about 1.25: 1, or at least about 1.5: 1. The width of the first openings 1212 of the fixed section 1210 and the width of the second opening 1246 of the rotatable section 1240 are substantially equal, so that the ratio WH: WR is at least about 0.85: 1, at least about 0.95: 1, or at least 0.98: 1 and / or no more than 35 about 1.15: 1, no more than about 1.05: 1, or no more than about 1.01: 1.

[0100] As shown generally in Figure 13a, each of the plates 1244a-d may be coupled to the second end 1243b of the housing 1242 and may generally extend towards the first end 1243a of the housing 1242 in a direction towards the first and second openings 1212 and 1244. Each of the plates 1244a-d 40 may have an extension or length distance, shown as Le in Figure 13b, of at least about 0.1λ, of at least about 0.2λ , of at least about 0.25λ and / or of not more than about 0.5λ, of not more than about 0.35λ, or of not more than about 0.30λ. Additionally, as shown in particular in Figure 13c, one or more of the plates 1244a-d may have a thickness, k, of at least about 0.01λ, of at least about 0.05λ and / or of not more than about 0.10λ, or not more than about 0.075λ, where λ is the wavelength of the microwave energy introduced into the housing 1242 by a first opening 1212. Adjacent plates 1244a-d may be separated by a distance spacing, j, which may be greater than, about equal to, or less than the thickness of each plate. In one embodiment, j may be at least about 0.01λ, at least about 0.05λ and / or no more than about 0.10λ, or no more than about 0.075λ. Therefore, in one embodiment, the ratio of the cumulative surface area of the distal ends of the plates 1244a-d, generally illustrated as the shaded regions in Figure 13c, relative to the total area of internal exposed surface of the second end 1243b of the housing 1242, generally illustrated as the non-shaded regions in Figure 13c, may be at least about 0.85: 1, at least about 0.95: 1, or at least about 0.98: 1 and / or no more than about 1.15: 1, no more than about 1.10: 1, or no more than about 1.05: 1.

[0101] Variable phase short circuit 1230 can be configured to rotate at a speed of at least 50 55 revolutions per minute (rpm), at least about 100 rpm, at least about 150 rpm and / or no more than about 1000 rpm, no more than about 900 rpm, or no more than about 800 rpm around the axis of rotation 1211, as illustrated in Figure 13a. In one embodiment, at least a portion of the movement of the rotating variable phase short circuit 1230 can be carried out by means of an actuator 1270 coupled to an automatic controller and / or a control system

automatic (not shown). In another embodiment, at least a portion of the movement can be carried out manually and may optionally include periods of non-rotation.

[0102] Additional embodiments of rotating phase change devices 1233 and 1235 suitable for use in a microwave distribution system 514 of Figure 6a are illustrated, respectively, in Figures 13e and 13f. 5 As shown in the embodiment depicted in Figure 13e, the rotating phase change device 1233 may include a rotating crank element 1237 coupled by a fixing rod 1239 to a plunger 1241 disposed within a waveguide 1243. As crank element 1237 rotates as indicated by arrow 1261, rod 1239 facilitates a general top-down movement of piston or plunger 1241 within waveguide 1243, as indicated by arrow 1263 in Figure 13e. Another embodiment of a rotating phase change device 1235 is illustrated in Figure 13f, including a cam 1245 coupled to a rod extension, which may be integrated with or coupled to a plunger 1241 disposed within the waveguide 1243. When the cam 1245 rotates, the rod extension 1247 moves the piston or piston 1241 with a general movement from top to bottom inside the cylinder 1243, as generally indicated by arrow 1263. Also, according to one embodiment, the rotary phase change device 1235 it may further comprise one or more diverter devices 1249 (for example, one or more springs) to facilitate movement of the plunger 1241 within the waveguide 1243 in an upward direction.

[0103] In addition to being used as a rotating phase change device, variable phase short circuit 1230 (or optionally, rotating phase change devices 1233, 1235) can also be configured to be used as a tuning device such as, For example, an impedance tuner to de-tune or cancel unwanted reflections and / or as a frequency tuner to match the generator frequency to that of the cavity.

[0104] Turning now to Figure 14a, an embodiment of a microwave distribution system 1314 using two variable phase short circuits 1330a, b as an impedance tuner to cancel or minimize the reflected power is illustrated. As shown in Figure 14a, each of the variable phase short circuits 1330a, b may be connected to adjacent outputs of a coupler 1340, which may be a hybrid short-slot coupler. In operation, each of the variable phase short circuits 1330a, b can be individually adjusted to a desired position so that the impedance tuner tunes the reflected energy of the microwave launcher 1322 back towards the generator 1312. According to one embodiment, one or both variable phase short circuits 1330 a, b can be further adjusted as necessary during the microwave process in order to adapt changes in the reflection coefficient of the items being heated. In one embodiment, the additional adjustments can be made at least partially using an automatic control system (not shown).

[0105] Variable phase short circuits as described herein can also be used as frequency tuners to match the frequency of the cavity with the frequency of the generator. According to this embodiment, one or more variable phase short circuits, shown as variable phase short circuit 1330c in Figure 14b, can be directly coupled to individual ports spaced along a resonant microwave chamber 1320. In this embodiment, the short circuit Variable phase 1330c can be rotated continuously or sporadically and its position can be adjusted manually or automatically depending on changes inside the microwave chamber 1320 40 and / or the items being processed in it (not shown). As a result of this adjustment of the variable phase short circuit 1330c, the frequency of microwave energy within the cavity can be more rigorously matched to the generator frequency (not shown).

[0106] Referring again to the microwave heating system 510 illustrated in Figure 6a, heating of articles 550 passed through microwave chamber 520 can be carried out more rigorously and efficiently by, for example, , the increase of the heat transfer coefficient between the articles and the surrounding fluid medium. An embodiment of a microwave chamber 1420 configured to facilitate heating of articles 1450 more quickly and efficiently by changes in the heat transfer coefficient within microwave heating chamber 1420 is illustrated in Figure 15a. In one embodiment, the heat transfer coefficient within the microwave chamber 1420 can be increased, at least in part, by stirring the liquid or gaseous medium within the chamber 1420, using one or more stirring devices such as, for example , one or more fluid jet agitators 1430a-d configured to turbulently discharge one or more fluid jets into the interior of the microwave chamber 1420. In one embodiment, the fluid jets discharged into the microwave chamber 1420 they can be a jet of liquid or steam and can have a Reynolds number of at least about 4500, at least about 8000 or at least about 10,000.

[0107] Structurally, fluid jet stirrers 1430a-d can be any device configured to discharge multiple jets to items 1450 at multiple locations within the microwave chamber

1420. In one embodiment, the fluid jet agitators 1430 may be axially spaced along the central elongation axis 1417 of the microwave chamber 1420 such that at least a portion of the jets is configured to discharge in one direction. generally perpendicular to the central axis of elongation 1417. In another embodiment, particularly illustrated in Figure 15b, one or more fluid jet agitators 1430a-b may be positioned circumferentially within the microwave chamber 1420 such that at least a portion 5 of the jets is directed radially inward toward the central axis of elongation 1417 of the chamber 1420. Although shown in Figure 15a as generally continuous along a portion of the circumference of the microwave chamber 1420, it has been of understanding that the fluid jet stirrer 1430a can also include multiple distinct jets, radially separated from each other í along at least a portion of the circumference of the chamber 1420, each located to discharge a stream of fluid towards the central axis of elongation 1417 of the chamber 1420. 10

[0108] As shown in Figure 15a, fluid jet agitators 1430a-d may be located along one or more sides of microwave chamber 1420 and may be intercalated (alternately) with one or more launchers of microwave 1422. The use of one or more stirrers 1430a-d can increase the heat transfer coefficient between the fluid medium within the microwave chamber 1420 and the articles 1450 by at least 15 about 1 percent, at least about 5 percent, at least about 10 percent, or at least about 15 percent, compared to the heat transfer coefficient of an inactive chamber, ceteris paribus. In the same or another embodiment, one or more jets configured and / or operated similarly may be included within one or more different zones of the microwave system 10 including thermalization and / or permanence zones 12 and / or 20, previously illustrated in Figures 1a and 1b. twenty

[0109] Again in reference to Figures 1a and 1b, after being removed from the microwave heating zone 16, the heated articles can then optionally be directed to a temperature retention zone 20, in which the temperature of the articles at or above a certain minimum threshold temperature for a specified period of residence. As a result of this maintenance stage, the items removed from the retention zone 20 may have a more uniform heating profile and fewer cold spots. In one embodiment, the minimum threshold temperature within the maintenance zone 20 may be the same as the minimum temperature required within the microwave heating zone 16, and may be at least about 120 ° C, at least about 121 ° C, at least about 122 ° C, and / or no more than about 130 ° C, no more than about 128 ° C, or no more than about 126 ° C. The average residence time of the articles that pass through the retention zone 30 20 can be at least about 1 minute, at least about 2 minutes, or at least about 4 minutes and / or not more than about 20 minutes, no more than about 16 minutes, or not more than about 10 minutes. The retention zone 20 may be operated at the same pressure as the microwave heating zone 16 and may, in one embodiment, be at least partially defined within a pressurized chamber or vessel and / or filled with liquid.

 35

[0110] After leaving the retention zone 20, the heated items of the microwave system 10 can then be introduced into a cooling zone 22, where the heated items can be rapidly cooled by contact with one or more refrigerated fluids. In one embodiment, the cooling zone 22 may be configured to cool the items by at least about 30 ° C, at least about 40 ° C, at least about 50 ° C, and / or no more than about 100 ° C, no more than about 75 ° C, or no more of about 50 ° C for a period of at least about 1 minute, at least about 2 minutes, at least about 3 minutes and / or no more than about 10 minutes, no more than about 8 minutes, or no more than about 6 minutes . It is possible to use any suitable type of fluid as a cooling fluid in the cooling zone 22, including, for example, a liquid medium such as those described above with respect to the microwave heating zone 16 and / or a gaseous medium.

 Four. Five

[0111] According to an embodiment generally depicted in Figures 1a and 1b, the microwave heating system 10 may also include a second pressure adjustment zone 14b disposed downstream of the microwave heating zone 16 and / or the retention zone 20, when it exists. The second pressure adjustment zone 14b may be configured and operated in a manner similar to that described above with respect to the first pressure adjustment zone 14a. When present, the second pressure adjustment zone 14b may be located downstream of the cooling zone 22, such that a substantial portion or almost the entire cooling zone 22 operates at a similar (super atmospheric) high pressure. at the pressure under which the microwave heating zone 16 and / or the retention zone 20 operate. In another embodiment, the second pressure adjustment zone 14b may be disposed within the cooling zone 22, so that a part of the cooling zone 22 can operate at a super-atmospheric pressure similar to the pressure of the microwave heating zone 16 and / or the retention zone 20 while another part of the cooling zone 22 can operate at about atmospheric pressure. When removed from the cooling zone 22, the cooled articles may have a temperature of at least about 20 ° C, at least about 25 ° C, at least about 30 ° C, and / or no more than about 70 ° C, no more than about 60 ° C, or not more than about 50 ° C. Once removed from the cooling zone 22, the cooled and treated items can

then withdraw from the microwave heating zone 10 for later storage or use.

[0112] In accordance with an embodiment of the present invention, one or more methods are provided to control the operation of the microwave heating system 10, for example, to ensure a constant and continuous exposure to microwave energy for each article or container passing through the microwave 5 heating system 10. The main steps of an embodiment of a method 1500 suitable for controlling the operation of the microwave system 10 are represented by individual blocks 1510-1530 in Figure 16.

[0113] As depicted in Figure 16, the first stage of control method 1500 is to determine a value for one or more microwave system parameters related to microwave heating zone 16, as 10 is represented by block 1510 Examples of microwave system parameters may include, but are not limited to, net discharged power, speed of the conveyor system and temperature and / or flow of water contained within the microwave heating chamber. Subsequently, as shown in block 1520 of Figure 16, the resulting determined value for the specific parameter can then be compared with a corresponding target value for the same parameter in order to determine a difference. Based on the difference, one or more actions can be carried out to adjust the operation of the microwave system 10, as shown in block 1530 of Figure 16. In one embodiment, the adjustment of the microwave heating system 10 can be undertaken when, for example, the magnitude of the difference is at least 5 percent, at least 10 percent, or at least 20 percent of the value of the target value and / or the value determined for the parameter microwave system specific. In one embodiment, at least a portion of the method described above can be carried out using an automatic control system.

[0114] In one embodiment, the microwave heating system 10 may use the basic steps of the control method described above 1500 to ensure compliance with safety and / or regulatory requirements of the items (eg food and / or fluids or medical instruments) that are getting warm inside. According to this embodiment, the one or more microwave system parameters may be selected from the group consisting of minimum net power discharged, maximum speed of the transport system, and minimum temperature and / or minimum flow of water within the heating chamber. by microwave In one embodiment, the minimum water temperature in the microwave chamber may be at least about 120 ° C, at least about 121 ° C, at least about 123 ° C and / or no more than about 130 ° C, no more than about 128 ° C, or no more than about 126 ° C, while the minimum flow can be at least about 1 gallon per minute (gpm), at least about 5 gpm, or at least about 25 gpm. The maximum speed of the conveyor system, in one embodiment, may be no greater than about 15 feet per second (fps), no greater than about 12 fps, or no more than 10 fps and the minimum net power discharged may be at least about 50 kW, at least about 75 kW, or at least about 100 kW. When control method 1500 is used to ensure safety or compliance with product regulations, the one or more actions taken to adjust the operation of the microwave heating system 35 may include, but not be limited to, stopping the system. transport, shut down one or more generators, remove, isolate and reprocess or dispose of one or more items exposed to undesirable conditions, and combinations thereof.

[0115] In the same or another embodiment, the microwave heating system 10 can also use the basic steps 40 of the control method 1500 to ensure the quality and uniformity between the items (eg, food and / or fluids or instruments doctor) that get hot. According to this embodiment, the microwave parameters may include net discharged power, speed of the conveyor system and the temperature and / or flow of the water contained within the microwave heating chamber. In one embodiment, the temperature of the water in the microwave chamber can be at least about 121 ° C, at least about 122 ° C, at least about 123 ° C and / or no more than about 130 ° C, no greater than 45 about 128 ° C, or not greater than about 126 ° C, while the flow rate can be at least about 15 gallons per minute (gpm), at least about 30 gpm, or at least about 50 gpm. The speed of the conveyor system, in one embodiment, can be controlled to be a speed no greater than about 5 feet per second (fps), no greater than about 7 fps, no greater than about 10 fps and the net power discharged can be at minus about 75 kW, at least about 100 kW, or at least about 150 kW. When the control method 1500 is used to ensure the quality or uniformity 50 of the product, the action or actions taken to adjust the operation of the microwave heating system 10 may include, but are not limited to, stopping the transport system, turning off one or more generators, remove, isolate and reprocess or dispose of one or more items exposed to undesirable conditions, and combinations thereof.

[0116] To perform comparison step 1520 of method 1500 shown in Figure 16, one or more of the target values for at least one of the parameters of the microwave system described above can be determined before heating the items in the microwave system 10. The magnitude of these target values can be determined by first creating a prescribed heating profile for the specific type of article to be heated using a small-scale microwave system. For example, in one embodiment, one or more articles of a specific type

(for example, food, medical devices, or medical fluids) are first loaded into a microwave chamber of a small-scale microwave heating system. In one embodiment, the articles loaded in the small-scale heating chamber can be of only one type, so that the resulting determined prescribed heating can be applied specifically to that type of article in a larger-scale heating system. In one embodiment, the article may be a specific type and / or size of packaged food (for example, an 8-ounce package of meat ready to eat) or it may be a packaged medical fluid (eg, saline solution) or types and / or specific containers of medical or dental instruments.

[0117] Once loaded in the microwave chamber of the small-scale microwave heating system, the article can be heated by introducing microwave energy into the chamber by one or more 10 microwave launchers. During this heating period, which may include multiple heating batches, a prescribed heating profile for the item being heated can be determined. As used herein, the term "prescribed heating profile" refers to a set of target values of a variety of parameters suggested or recommended for use when a specific type of item is heated. In addition to including target values, the prescribed heating profiles can also be expressed, at least in part, as a function of time and / or position of the article. In one embodiment, the prescribed heating profile may include at least one target value for one or more of the microwave system parameters that include, but are not limited to, net power discharged, microwave power sequential distribution (i.e., specifications regarding timing, status and amount of microwave energy discharged), temperature and / or flow rate of the fluid (for example, water) in the microwave chamber, and / or residence time of the article within the microwave chamber. In addition, the prescribed heating profile may also include target or minimum values for one or more parameters (for example, temperature, fluid flow rate, pressure, and residence time of the article) relative to thermalization, retention and / or cooling zones 16, 20, 22 of the microwave heating system 10.

[0118] Once a prescribed heating profile has been determined, multiple items of said type can be loaded into a large-scale microwave heating system and can then be heated according to the prescribed profile determined with the small microwave system scale, optionally using an automatic control system. In one embodiment, the small-scale microwave heating system may be a batch or semi-batch system and / or may comprise a liquid-filled chamber having a total internal volume of less than 100 cubic feet, less than 50 feet cubic, or less than 30 cubic feet. In the same or another embodiment, the large-scale microwave system 30 can be a continuous or semi-continuous process carried out at least partially in a pressurized or liquid filled microwave chamber having a total internal volume of at least 100 cubic feet, at least 250 cubic feet, or at least 500 cubic feet. The steps described above can then be repeated as many times as necessary to create specific prescribed heating profiles for any number of different items. Subsequently, target values of one or more parameters described above can be determined and used in comparison step 1520 of method 1500 shown in Figure 16. After that and based on the difference, one or more can be performed. actions of those mentioned above to ensure uniform heating of the final product.

[0119] One aspect of ensuring uniform heating is to ensure that a constant and measurable power is discharged into the heating zone. In one embodiment, a method is provided to control the net power discharged within the microwave heating system 10. As used herein, the term "net power discharged" refers to the difference between the direct and reflected power within a waveguide. or pitcher As used herein, the term "direct power" refers to the power that propagates in a predicted direction from the generator to a load, while the term "reflected power" refers to the power that propagates in an unwanted direction, usually from charging back to a waveguide or launcher and towards the generator.

[0120] The main steps of a 1600 method for determining the net power discharged from at least one microwave launcher using two or more pairs of directional couplers are summarized in flow chart 50 provided in Figure 17. As depicted in the blocks 1610 and 1620, a first and second values can be determined for net power discharged using two independent pairs of directional couplers. Each pair of directional couplers can include a coupler to measure the direct power and another to measure the reflected power, and one or more devices or systems to calculate the difference, in order to provide a first and second respective values for the net power discharged. According to one embodiment, at least one of the net power values can be used to adjust or control the production of the microwave generator, while the other can be used as reinforcement or validation of the other.

[0121] Once values of each pair of couplers have been obtained, the first and second net power values

they can be compared to determine a difference, as illustrated in block 1630, and, based on the difference, one can act to adjust the operation of the microwave heating system, as depicted in block 1640. In one embodiment, the action can be executed when the difference exceeds a predetermined value, such as a value that is at least about 1 percent, at least 2 percent, or at least 5 percent of the first and / or second values of net power determined previously. In one embodiment, an action can also be performed when the difference is at least 1 percent, at least 2 percent, or at least 3 percent of the lowest of the first and second net power values. In another embodiment, an action can also be executed if one of the first or second net power values is below a predetermined minimum and / or exceeds a predetermined maximum. Depending, at least in part, on the items being processed and the difference determined, the action may include, but is not limited to, shutting down a generator or conveyor system, 10 increasing or reducing generator production, and / or remove, isolate and dispose of or re-process one or more items that were placed inside the microwave heating chamber when the difference exceeded the predetermined value

[0122] The microwave heating systems of the present invention can be commercial scale heating systems capable of processing a large volume of articles in a relatively short time. Unlike conventional retorts and other small-scale systems that use microwave energy to heat multiple items, microwave heating systems as described in this document may be configured to achieve total productivity of at least about 15 packages per minute. per transport line, of at least about 20 containers per minute per transport line, of at least about 25 containers per minute per line of 20 transport, or of at least about 30 containers per minute per transport line, which exceeds much the productivity that can be achieved by other heating systems.

[0123] As used herein, the term "containers per minute" refers to the total quantity of 8-ounce ready-to-eat food containers filled with whey gel that can be processed by a particular microwave heating system 25, according to the following procedure: an 8-ounce ready-to-eat food container filled with whey gel pudding marketed by Ameriqual Group LLC (Evansville, Indiana, USA) is connected to multiple temperature probes placed in the pudding at least five equidistant positions spaced along each x-, y- and z- axis, originating in the geometric center of the container, as shown in Figure 18. The package is then placed in a heating system by Microwave to be evaluated and heated until each of the 30 probes records a temperature above the specified minimum temperature (for example, 120º for sterilization systems). The time required to achieve said temperature profile, as well as the physical and dimensional information on the heating system, can then be used to calculate total productivity in containers per minute.

 35

[0124] The preferred forms of the invention described above are to be used for illustrative purposes only, and should not be used in a restrictive sense to interpret the scope of the present invention. Those skilled in the art could easily make obvious modifications to the above-mentioned example embodiment without departing from the spirit of the present invention.

 40

[0125] The inventors hereby declare their intention to rely on the Doctrine of Equivalents to determine and evaluate the reasonably acceptable scope of the present invention in relation to any apparatus that does not materially depart from but is outside the literal scope of the invention, as specified in the following claims.

Claims (14)

Claims 1. A microwave system (10) for heating a plurality of articles, said system comprising: a microwave chamber (620) configured to receive said items; a transport system (110) for transporting said articles through said microwave chamber (620) along a transport axis (642); and 5 a first microwave launcher (622a) configured to propagate microwave energy into said microwave chamber (620) along a first central launch axis (660a), characterized in that a first launch inclination angle of at least 2º and less than 15º is defined between said first central axis of launch (660a) and a plane normal to said transport axis (66a).  10 2. The system (10) of claim 1, further comprising a second microwave launcher (622b) configured to propagate microwave energy into said microwave chamber (620) along a second central launch axis ( 660b), wherein a second angle of inclination of launch of at least 2 ° is defined between said second central axis of launch (660b) and a plane normal to said transport axis (622).  fifteen 3. The system (10) of claim 2, wherein said first and second central launch axes (660a, 660b) are substantially parallel to each other. 4. The system (10) of claims 2 or 3, wherein said first and second central launch axes (660a, 660b) are located on opposite sides of said microwave chamber (620). twenty 5. The system (10) of claim 4, wherein said first and second microwave launchers (622a, 622b) are facing each other. 6. The system (10) of claims 2 or 3, wherein said first and second microwave launchers (622a, 622b) are located on the same side of said microwave chamber (620). 25 7. The system (10) of any one of claims 1 to 6, further comprising at least one microwave generator (512) for generating microwave energy with a wavelength λ, wherein said first launcher (622a) defines at least one launch opening (624) for discharging microwave energy in said microwave chamber (620), wherein said launch opening (624) has a width (w1) and a depth (d1), at 30 where w1 is greater than d1, where d1 is less than 0.625λ. The system (10) of claim 7, wherein said first microwave launcher (622a) is elongated in the direction of extension of said transport axis (642).  35 9. The system (10) of claim 7, wherein said first microwave launcher (622a) comprises an inlet (936) and two or more launch openings (938a, 938b, 938c) for discharging microwave energy into said microwave chamber (620), wherein each of said two or more launch openings (938a, 938b, 938c) has a depth less than 0.625λ.  40 10. The system (10) of any one of claims 7 to 9, further comprising at least one substantially substantially microwave transparent window (526) disposed between said microwave chamber (620) and said launch opening (624). 11. The system (10) of any one of claims 1 to 10, further comprising a thermalization zone (12) located upstream of said microwave chamber (620), said thermalization zone (12) configured to adjust the temperature of said articles at a substantially uniform temperature before the introduction of said articles in said microwave chamber (620). 12. The system (10) of any one of claims 1 to 11, wherein said microwave chamber (620) is a pressurized chamber configured to operate at a pressure of at least 15 psig. fifty 13. The system (10) of any one of claims 1 to 12, wherein said microwave system (10) is configured to sterilize or pasteurize packaged foods, medical fluids and / or medical instruments and wherein said microwave chamber (620) is filled with liquid.  55 14. The system (10) of any one of claims 1 to 13, wherein said microwave system (10) is configured to sterilize said packaged foods with a productivity equivalent to at least 150 packages per minute.