Method and apparatus for the prevention of scorching of fabric subjected to microwave heating

• US 5,424,515 A
• Filed: 10/15/1993
• Issued: 06/13/1995
• Est. Priority Date: 04/06/1992
• Status: Expired due to Fees

• Current Assignee: Micro Dry Incorporated
• Original Assignee: Micro Dry Incorporated
• Inventors: Gentile, Philip J.
• Primary Examiner(s): Leung, Philip H.
• Application Number:
  US08/136,151
• Time in Patent Office: 606 Days
• Field of Search: 219/702, 219/704, 219/706, 219/709, 219/736, 34/259, 34/260, 34/261, 34/262, 34/263, 34/265
• US Class Current: 219/702
• CPC Class Codes: D06F 58/266 Microwave heating equipment
• CPC Class Codes: F26B 25/22 Controlling the drying process in dependence on liquid content of solid materials or objects
• CPC Class Codes: F26B 3/347 Electromagnetic heating, e.g. induction heating or heating using microwave energy

Abstract

The present invention features a UV tube detector for sensing a resonant arcing condition in a microwave environment. Where clothing or fabric is being dried in a magnetron-powered, microwave chamber, the UV tube detector is placed in proximity to the fabric. The UV tube detector senses a possible resonant arcing condition related to small metal objects hidden in the material. Upon the sensing of arcing, the UV tube provides a signal for shutting down the magnetron power. In conjunction with UV detection, the moisture condition can be monitored during the drying cycle. At a point in the microwave heating cycle consistent with an "end of microwave heating cycle" or "near dryness", the power output of the magnetrons is reduced or terminated. The moist fabric can then be dried via reduced microwave heating and/or by normal heating methods, including, but not limited to, electrical radiant heating and convection techniques. In this manner, it is possible to bring the fabric to a state of dryness, despite the presence of resonant arc-producing objects.

Claims

1. In a microwave environment, including a power supply for a microwave generating source, and the presence of at least one small, metal object in a microwave-receiving chamber that is capable of producing a resonant arcing condition, the improvement comprising:

a UV-type detection device disposed in proximity to said small, metal object, for sensing radiant discharge therefrom in an approximate electromagnetic radiation range of between 100 and 800 nanometers, as a result of microwave-induced resonance.

2. The UV-type detection device of claim 1, wherein said UV-type detection device is synchronized with said power supply.

3. The UV-type detection device of claim 1, wherein said UV-type detection device comprises a UVtron.

4. The UV-type detection device of claim 1, wherein said UV-type detection device is located adjacent a lamp vent or air intake or exhaust vent in said chamber.

5. The UV-type detection device of claim 1, wherein said UV-type detection device is biased in a discharge or avalanche region.

6. A method of preventing an arcing condition in a microwave environment, comprising the steps of:

a) detecting an arcing condition in said microwave environment by sensing electromagnetic radiation in the approximate range of between 100 and 800 nanometers, utilizing a UV-type device disposed in said microwave environment;

b) generating a signal in response to said electromagnetic radiation sensing; and

c) adjusting generation of microwaves in said microwave environment in response to said signal.

7. The method of claim 6, wherein said adjusting step (c) further includes the step of:

i) terminating microwave generation.

8. The method of claim 6, wherein said adjusting step (c) further includes the step of:

i) powering-down microwave generation.

9. The method of claim 8, wherein said step (i) of powering-down microwave generation is accomplished as a function of water content in said microwave environment.