Determination of a heating profile for a large-scale microwave heating system

• US 9,301,345 B2
• Filed: 03/13/2013
• Issued: 03/29/2016
• Est. Priority Date: 03/14/2012
• Status: Active Grant

• Current Assignee: Microwave Materials Technologies, Inc.
• Original Assignee: Microwave Materials Technologies, Inc.
• Inventors: Kimrey, Harold Dail Jr.
• Primary Examiner(s): Jennison, Brian
• Application Number:
  US13/799,991
• Publication Number:
  US 20130240518A1
• Time in Patent Office: 1,112 Days
• Field of Search: 219/688, 219/762
• US Class Current: 1/1
• CPC Class Codes: A23L 3/01 using microwaves or dielectric heating
• CPC Class Codes: A23L 3/02 by heating materials in packages which are progressively transported, continuously or stepwise, through the apparatus
• CPC Class Codes: A23V 2002/00 Food compositions, function of food ingredients or processes for food or foodstuffs
• CPC Class Codes: A61B 90/70 Cleaning devices specially adapted for surgical instruments
• CPC Class Codes: A61L 2/04 Heat A61L2/08 takes precedence
• CPC Class Codes: A61L 2/12 Microwaves
• CPC Class Codes: A61L 2202/21 Pharmaceuticals, e.g. medicaments, artificial body parts
• CPC Class Codes: A61L 2202/24 Medical instruments, e.g. endoscopes, catheters, sharps
• CPC Class Codes: A61L 2202/26 Textiles, e.g. towels, beds, cloths
• CPC Class Codes: B65B 55/06 by heat
• CPC Class Codes: H01L 21/67201 characterized by the construction of the load-lock chamber
• CPC Class Codes: H05B 6/68 for monitoring or control
• CPC Class Codes: H05B 6/70 Feed lines
• CPC Class Codes: H05B 6/78 Arrangements for continuous movement of material
• CPC Class Codes: H05B 6/782 wherein the material moved is food
• CPC Class Codes: H05B 6/80 Apparatus for specific applications stoves or ranges F24C7/02

Abstract

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

Claims

1. A method for heating a plurality of articles, said method comprising:

(a) heating a first test article in a small-scale microwave heating system while conveying said first test article through a water-filled, small-scale microwave chamber having a total internal volume of less than 50 cubic feet, wherein at least a portion of said heating of step (a) is accomplished using microwave energy;

(b) determining a first prescribed heating profile based on said heating of step (a), wherein said prescribed heating profile comprises at least one value for one or more microwave system parameters selected from the group consisting of net power discharged into said chamber, sequential microwave power distribution, average temperature of the water in said microwave chamber, flow rate of the water in said microwave chamber, and residence time of said article in said microwave chamber; and

(c) heating a plurality of first commercial articles in a large-scale microwave heating system while conveying said first commercial articles through a water-filled, large-scale microwave chamber having a total internal volume of at least 250 cubic feet, wherein at least a portion of said heating of step (c) is accomplished using microwave energy, wherein each of said first commercial articles is substantially similar in size and composition to said first test article, wherein said heating of step (c) is controlled in accordance with said first prescribed heating profile determined in step (b).

2. The method of claim 1, wherein said heating of step (c) comprises introducing said microwave energy into said large scale microwave chamber via a plurality of microwave launchers, wherein said first prescribed heating profile specifies the amount of microwave energy to be discharged by each launcher.

3. The method of claim 1, wherein said first prescribed heating profile specifies a value for the average temperature of the water in said microwave chamber, wherein said value for the average temperature of the water is at least 120°

C.

4. The method of claim 1, wherein said first prescribed heating profile specifies a value for the residence time of said article in said microwave chamber, wherein said value for the residence time is at least 30 seconds and not more than 20 minutes.

5. The method of claim 1, further comprising prior to step (c), thermalizing at least a portion of said first commercial articles in a thermalization zone to a substantially uniform temperature, wherein at least a portion of said thermalizing is carried out according to said first prescribed heating profile determined in step (b).

6. The method of claim 5, further comprising subsequent to step (c), passing said first commercial articles into a holding zone, wherein the temperature of said first commercial articles is maintained at or above a minimum temperature for a specified time period within said holding zone.

7. The method of claim 6, wherein said minimum temperature is at least 120°

C. and said specified time period is at least 2 minutes and not more than 20 minutes.

8. The method of claim 1, further comprising repeating steps (a) and (b) with a second test article to thereby determine a second prescribed heating profile, repeating step (c) with a plurality of second commercial articles substantially similar in size and composition to said second test article, wherein said heating of said second commercial articles is carried in accordance with said second prescribed heating profile.

9. The method of claim 1, wherein said small-scale microwave heating system is a batch system and said large-scale microwave heating system is a continuous system.

10. The method of claim 1, wherein at least a portion of steps (a) and (c) are carried out with one or more automatic control systems.

11. The method of claim 1, wherein said first test and commercial articles comprise packages containing foodstuffs, medical fluids, or medical instruments.

12. The method of claim 1, wherein said large-scale microwave heating system is a sterilization system.

13. The method of claim 1, wherein said large-scale microwave heating system has an overall production rate of at least 20 packages per minute per convey line.

14. The method of claim 1, wherein said first commercial articles comprise packaged foodstuffs, medical fluids, or medical instruments, wherein said large-scale microwave chamber is pressurized to at least 10 psig during at least a portion of said heating of step (c).

15. The method of claim 1, wherein said first commercial articles comprise packaged foodstuffs, wherein said large-scale microwave chamber is pressurized to at least 15 psig during at least a portion of said heating of step (c), wherein said large-scale microwave heating system is configured to sterilize said packaged foodstuffs at a rate of at least 20 packages per minute per convey line.