Microwave wattage indicator

• US 4,916,386 A
• Filed: 03/20/1989
• Issued: 04/10/1990
• Est. Priority Date: 03/20/1989
• Status: Expired due to Fees

• Current Assignee: James E. Schulz
• Original Assignee: James E. Schulz
• Inventors: Schulz, James E.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): BURNS, WILLIAM
• Application Number:
  US07/325,918
• Time in Patent Office: 386 Days
• Field of Search: 324/92, 324/95, 324/106, 219/10.55 D, 219/10.55 E, 219/10.55 F, 374/162-164, 374/166, 374/31, 374/149, 374/150, 340/786
• US Class Current: 324/95
• CPC Class Codes: G01R 21/04 in circuits having distributed constants
• CPC Class Codes: G01R 22/04 by calorimetric methods
• CPC Class Codes: H05B 6/64 Heating using microwaves containers, packaging elements or packages specially adapted to be heated by microwaves B65D81/3446

Abstract

A microwave oven wattage detector having a visually and microwave transparent container holding a thermally homogeneous fluid having a wattage-indicating strip contained in the fluid with a plurality of different temperature-sensitive areas on the strip with indicia associated with each of the areas to indicate power levels when such container is heated within a microwave oven for a set time and one of such temperature-sensitive areas changes color to denote the indicia indicating the power level of the microwave oven.

Claims

1. A microwave oven wattage detector comprising:

a microwave transparent container;

a predetermined quantity M of thermally homogenous fluid at an initial temperature T₁ held within said container heated by said microwave oven for a fixed time t;

a wattage indicating strip heated to a final temperature T₂ by said fluid, said strip including a plurality of temperature-sensitive members, each to be activated and change color at a different temperature, such strip having indicia associated with each member corresponding to power levels to determine, for a particular temperature T₂ when the formula;

space="preserve" listing-type="equation">C.sub.p (T.sub.2 -T.sub.1)(M)(1/t)=energy/time=power

where

C_p =heat capacity;

units of joules/gram degrees F.

T₁ =temperature initial;

units of degrees F.

T₂ =temperature final;

units of degrees F.

M=mass of compound being heated;

units of grams

t=time of energy exposure;

units of seconds

is utilized, the power level of said microwave oven.

2. The device of claim 1 wherein said wattage-indicating strip is positioned on the exterior of said container in an area corresponding to where fluid is held within said container adapted when the fluid is heated within said container, such heated fluid will heat said wattage-indicating strip through said container.

3. The device of claim 1 wherein said container is made of a visually transparent material.

4. The device of claim 3 wherein said wattage-indicating strip is positioned in the fluid in said container.

5. The device of claim 4 wherein said wattage-indicating strip comprises a plurality of liquid crystal members.

6. The device of claim 5 further including a mask overlay of the same color of the unactivated liquid crystal members, said mask having a plurality of clear areas forming indicia, said clear areas disposed over each of said liquid crystal members, said clear areas allowing the color change of an activated liquid crystal member to be visible therethrough thereby visually displaying the indicia of said mask overlay.

7. The device of claim 6 wherein said indicia on said mask overlay designates the power level of said microwave oven.

8. The structure of claim 7 wherein said container further includes a cap member adapted to be released from said container upon a pressure buildup in said container.

9. The device of claim 1 wherein the indicia associated with said temperature-sensitive members is positioned and printed adjacent to its related member.

10. The device of claim 6 wherein one of said indicia designates the initial temperature T₁ of said temperature-sensitive members by displaying the word "Start."

11. A method for determining wattage of a microwave oven comprising the steps of:

providing a microwave-transparent container of a predetermined quantity M of thermally homogenous fluid;

providing a plurality of temperature-sensitive members, each to change color al a plurality of different ascending temperatures;

providing indicia indicating power levels associated with each of said temperature-sensitive members, said indicia associated with the temperature-sensitive member that changes color upon heating in said microwave oven corresponding to the T₂ in the formula;

space="preserve" listing-type="equation">C.sub.p (T.sub.2 -T.sub.1)(M)(1/t)=energy/time=power

where

C_p =heat capacity;

units of joules/gram degrees F.

T₁ =temperature initial;

units of degrees F.

T₂ =temperature final;

units of degrees F.

M=mass of compound being heated;

units of grams

t=time of energy exposure;

units of seconds

for determining the power level of a particular microwave oven;

cooling said container to an initial temperature T₁ ;

exposing said container to microwave radiation in said oven for a preset period of time t;

determining by visual observation which of the temperature-sensitive members is visible; and

associated indicia of said member which indicates the power level of said microwave oven.