Microwave heating control and calorimetric analysis

• US 4,541,729 A
• Filed: 10/26/1983
• Issued: 09/17/1985
• Est. Priority Date: 01/11/1982
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Schubring, Norman W.
• Primary Examiner(s): Frankfort, Charles
• Assistant Examiner(s): Will, Thomas B.
• Application Number:
  US06/545,469
• Time in Patent Office: 692 Days
• Field of Search: 374/31, 374/142, 374/149, 374/43, 374/122, 374/33, 374/21, 374/101, 219/10.55 B, 324/58.5 R, 324/58.5 A, 324/58.5 B, 324/58.5 C, 34/1, 34/89, 426/241
• US Class Current: 374/31
• CPC Class Codes: H05B 6/68 for monitoring or control
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

In accordance with a preferred embodiment, calorimetric properties of a microwave heatable work load are obtained while the load is being heated by producing electrical signals indicative of the net applied microwave power and the temperature of the material, and using the signals to produce a signal indicative of the net energy, or the specific heat, or the reflection coefficient of the work load as a function of its temperature.

Claims

1. A method of using microwave energy to obtain calorimetric data on a work load that is heatable with microwaves, comprising

subjecting a load of such material to microwave energy while the material is situated in a cavity receptive to the microwave energy and retentive of radiation from the heated load, said microwave energy being generated at a source remote from said cavity and conducted to the cavity through a suitable microwave waveguide,

producing an electrical signal indicative of the temperature of the load in said cavity while it is being heated with said microwave energy,

monitoring microwave power transmitted through the waveguide from said source to the cavity and microwave power reflected from the cavity back through the waveguide toward the source while the load is being heated by said microwave energy and producing electrical signals indicative of said microwave power levels, and

processing said temperature indicative signal and said microwave power level signals by electrical analog circuit to obtain a signal indicative of the microwave energy input to the heated work load as a function of the temperature of the work load which is an indication of calorimetric data of the work load while it is being heated by said microwave energy.

2. A method of using microwave energy to obtain calorimetric data on a work load that is heatable with microwaves, comprising

subjecting a load of such material to microwave energy while the material is situated in a cavity receptive to the microwave energy and retentive of radiation from the heated load, said microwave energy being generated at a source remote from said cavity and conducted to the cavity through a suitable microwave waveguide,

producing an electrical signal indicative of the temperature of the load in said cavity while it is being heated with said microwave energy,

monitoring microwave power transmitted through the waveguide from said source to the cavity and microwave power reflected from the cavity back through the waveguide toward the source while the load is being heated by said microwave energy and producing electrical signals indicative of said microwave power levels, and

processing said temperature indicative signal and said microwave power level signals by electrical analog circuit to obtain a signal indicative of the reflection coefficient of the heated work load as a function of its temperature which is indication of calorimetric data of the work load while it is being heated by said microwave energy.

3. A method of using microwave energy to obtain specific heat data on a work load that is heatable with microwaves, comprising

subjecting a load of such material to microwave energy while the material is situated in a cavity receptive to the microwave energy and retentive of radiation from the heated load, said microwave energy being generated at a source remote from said cavity and conducted to the cavity through a suitable microwave waveguide,

continually producing a voltage indicative of the temperature of the load in said cavity while it is being heated with said microwave energy,

monitoring microwave power transmitted through the waveguide from said source to the cavity and microwave power reflected from the cavity back through the waveguide toward the source while the load is being heated by said microwave energy and continually producing a voltage indicative of the net microwave power absorbed by said load, and

continually producing a voltage indicative of the rate of change of said applied power to the heated work load with temperature using said temperature indicative voltage and said net power indicative voltage which is an indication of specific heat data of the work load while it is being heated by said microwave energy.

4. A method of using microwave energy to obtain specific heat data on a work load that is heatable with microwaves, comprising

subjecting a load of such material to microwave energy while the material is situated in a cavity receptive to the microwave energy and retentive of radiation from the heated load, said microwave energy being generated at a source remote from said cavity and conducted to the cavity through a suitable microwave waveguide,

continually producing a voltage indicative of the temperature of the load in said cavity while it is being heated with said microwave energy,

monitoring the microwave power transmitted through the waveguide from said source to the cavity and microwave power reflected from the cavity back through the waveguide toward the source while the load is being heated by said microwave energy, and continually producing a voltage indicative of the net microwave power absorbed by said load, and

continually producing a voltage indicative of the net energy input to the heated work load as a function of its temperature using said temperature indicative voltage and said net power indicative voltage which is at indication of specific heat data of the work load while it is being heated by said microwave energy.

5. A method of using microwave energy to obtain specific heat data on a work load that is heatable with microwaves, comprising

subjecting a load of such material to microwave energy while the material is situated in a cavity receptive to the microwave energy and retentive of radiation from the heated load said microwave energy being generated at a source remote from said cavity and conducted to the cavity through a suitable microwave waveguide,

continually producing a voltage indicative of the temperature of the load in said cavity while it is being heated with said microwave energy,

monitoring microwave power transmitted through the waveguide from said source to the cavity and microwave power reflected from the cavity back through the waveguide toward the source while the load is being heated by said microwave energy and continually producing a voltage indicative of the net microwave power absorbed by said load, and

continually producing a voltage indicative of the specific heat of the heated work load as a function of its temperature using said temperature indicative voltage and said net power indicative voltage.