WINDOWED HIGH-TEMPERATURE OVENS

• US 3,612,825 A
• Filed: 08/08/1969
• Issued: 10/12/1971
• Est. Priority Date: 08/08/1969
• Status: Expired due to Term

• Current Assignee: Harold E. Mckelvey, Joseph E. Jendrisak, William Byer Chase
• Original Assignee: Harold E. Mckelvey, Joseph E. Jendrisak, William Byer Chase
• Inventors: Chase, William Byer, Jendrisak, Joseph E., McKelvey, Harold E.
• Primary Examiner(s): Mayewsky, Volodymyr Y.
• Application Number:
  US04/848,547
• Time in Patent Office: 795 Days
• Field of Search: 219/522,396,400,399,405,347,393,343,347,369 165/122 98/87-88 126/110,21A,200,198,21 20/56.5
• US Class Current: 219/405
• CPC Class Codes: F24C 14/02 pyrolytic type
• CPC Class Codes: F24C 15/04 with transparent panels

Abstract

Windowed high-temperature ovens including self-cleaning ovens and the like, and windowed doors for those ovens, and window assemblies for installation in such ovens, where the window assembly has at least three spaced parallel glass window panels secured in alignment with two of such panels near the oven cavity enclosing a dead-air or insulating space, and a third of such glass window panels separated from the oven cavity by two deadair space enclosing glass panels, with the space between the third panel and the two dead-air enclosing panels being ventilated for replacement of heated air therein by cooler air, and a thin semitransparent see-through through metal reflector disposed in the ventilated airspace to reflect substantial proportions of radiant oven heat and to be cooled by air wash during such ventilation.

Claims

1. In a windowed household self-cleaning oven having a heatinsulated structure defining an oven cavity, heating means for heating said oven cavity, controlling means for controlling said heating means to obtain various temperature combinations in the oven cavity in the cooking range of about 150* F. to 550* F. and in a cleaning range in excess of about 750* F. but less than about 1,200* F., and at least three transparent panels secured in said heat-insulated structure in spaced substantially parallel relation, including a first transparent panel, a second transparent panel adjacent said first panel and separated from said oven cavity by said first panel, and a third transparent panel separated from said first panel by said second panel, the improvement comprising means essentially sealing the space between said first and second panels to provide a dead-air space therebetween;

a thin semitransparent reflective coating on one of the surfaces of said panels, located between said second and third panels and formed of a substantially nonchemically reactive metal having a thermal conductivity in excess of about 40 B.t.u./(ft.2hr. * F./in.) at 212* F. and a surface emissivity less than about 0.50 throughout the temperature range between about 750* F. and 950* F.;

a cool air intake communicating with the space housing said reflective coating; and

a warm air outlet communicating with the space housing said reflective coating, so that when heat escapes from said oven cavity past the dead-air space between said first and second panels, substantial amounts of said escaping heat impinge upon said reflective coating, portions of which are reflected back toward said cavity and other portions of which are absorbed by said coating, said coating being cooled by the flow of air across it from said air intake to said air outlet to maintain the outermost exposed surface of the outermost transparent panel at a temperature below 265* F.

2. A windowed oven as recited in claim 1 wherein said heating means are electric.

3. A windowed oven as recited in claim 1 wherein said heating means are gas.

4. In a windowed household self-cleaning oven having a heat-insulated structure defining an oven cavity having a front opening, heating means for heating said cavity, controlling means for controlling said heating means to obtain various temperature combinations in the oven cavity in the cooking range of about 150* F. to 550* F. and in a cleaning range in excess of about 750* F. but less than 1,200* F., a door operatively mounted in said front opening, and a window mounted in said door comprised of at least three transparent glass panels in spaced substantially parallel relation, including a first transparent glass panel, a second transparent glass panel adjacent said first panel and separated from said oven cavity by said first panel, and a third transparent glass panel separated from said first panel by said second panel, the improvement comprising means essentially sealing the space in said door between said first and second panels to provide a dead-air space therebetween adjacent said oven cavity;

a thin semitransparent reflectIve coating located between said second and third panels on one of the surfaces of said panels, said coating formed of a substantially nonchemically reactive metal having a thermal conductivity in excess of about 40 B.t.u./(ft.2hr. * F./in.) at 212* F. and a surface emissivity less than about 0.50 throughout the temperature range between about 750* F. and 950* F.;

a cool air intake at the bottom of said door communicating with the space housing said reflective coating; and

a warm air outlet at the top of said door communicating with the space housing said reflective coating, so that when heat escapes from said oven cavity past the dead-air space between said first and second panels, substantial amounts of said escaping heat impinge upon said reflective coating, portions of which are reflected back toward said cavity and other portions of which are absorbed by said coating, said coating being cooled by the flow of air across it through said door from said air intake to said air outlet to reduce the amount of heat transmitted to the outermost transparent panel and maintain the outermost exposed surface of such panel at a temperature below 265* F.

5. A windowed oven as recited in claim 4 wherein said thin reflective coating is foraminous and the ratio of the total reflective surface area of said coating to the total area of the foramens in said coating is between about 3:

1 and 1;

2.

6. A windowed oven as recited in claim 5 wherein said coating is foraminous and the foramens have an area greater than about one-sixteenth square inch;

and wherein said first panel is of borosilicate glass.

7. A windowed oven as recited in claim 6 wherein said reflector has a thickness not greater than about 1,500 Angstroms.

8. A windowed oven as recited in claim 7 wherein the principal component of said coating is gold, platinum, or an alloy of either or both of such metals.

9. A windowed oven as recited in claim 4 wherein said thin reflective coating is foraminous, and the foramens in said foraminous coating have an average area not greater than about one-sixteenth sq. in.

10. A windowed oven as recited in claim 4 wherein said reflector has a thickness not greater than about 200 Angstroms.

11. A windowed oven as recited in claim 7 wherein the principal component of said coating is gold, platinum, or an alloy of either or both gold and platinum.

12. A windowed oven as recited in claim 4 wherein said thin reflective coating is foraminous and the ratio of the total reflective surface area of said coating to the total area of the foramens in said coating is about 3:

2.

13. A windowed oven as recited in claim 4 wherein the principal component of said coating is gold, platinum, or an alloy of either or both gold or platinum.

14. A windowed oven as recited in claim 4 wherein said coating has a thickness not greater than about 1,500 Angstroms.

15. In a windowed household self-cleaning oven having a heat-insulated structure defining an oven cavity, said heat-insulated structure having an opening, heating means for heating said oven cavity, and controlling means for controlling said heating means to obtain various temperature combinations in the oven cavity in the cooking range of about 150* F. to 550* F. and in a cleaning range in excess of about 750* F. but less than about 1,200* F., the improvement comprising four transparent glass panels secured in said opening in said heat-insulated structure in spaced substantially parallel relation, including a first transparent glass panel, a second transparent glass panel adjacent said first panel and separated from said oven cavity by said first panel, a third transparent glass panel separated from said first panel by said second panel, and a fourth transparent glass panel located between said second and third panels;

means essentially sealing tHe space between said first and second panels to provide a dead-air space therebetween;

a thin semitransparent reflective coating located between said second and third panels on a surface of one of said second, third and second fourth transparent panels, said coating formed of a substantially nonchemically reactive metal having a thermal conductivity in excess of about 40 B.t.u./(ft.2hr. * F./in.) at 212* F. and a surface emissivity less than about 0.50 throughout the temperature range between about 750* F. and 950* F.;

a cool air intake at the bottom of the space housing said reflective coating; and

a warm air outlet at the top of the space housing said reflective coating so that when heat escapes from said oven cavity past the dead-air space between said first and second panels, substantial amounts of said escaping heat impinge upon said reflective coating, portions of which are reflected back toward said cavity and other portions of which are absorbed by said coating, said coating being cooled by the flow of air across it from said air intake to said air outlet to maintain the outermost exposed surface of the outermost transparent panel at a temperature below 265* F.

16. A windowed oven as recited in claim 15 wherein said coating is foraminous and the ratio of the total reflective surface area of said coating to the total area of the foramens in said coating is about 3:

2.

17. A windowed oven as recited in claim 15 wherein said coating is foraminous and the ratio of the total reflective surface area of said coating to the total area of the foramens in said coating is between about 3:

1 and 1;

2.

18. A windowed oven as recited in claim 17 wherein said coating has a thickness of about 1,500 Angstroms or less.

19. A windowed oven as recited in claim 18 wherein said coating is foraminous and the foramens in said foraminous coating have an average area not greater than about one-sixteenth square inch.

20. A windowed oven as recited in claim 15 wherein the principal component of said coating is gold, platinum, or an alloy of either or both gold or platinum.

21. A windowed oven as recited in claim 15 wherein said coating is foraminous and the foramens in said foraminous coating have an average area not greater than about 0.02 square inch.

22. A windowed oven as recited in claim 15 wherein said coating has a thickness not greater than about 1,500 Angstroms.

23. In a windowed household self-cleaning oven having a heat-insulated structure defining an oven cavity, said heat-insulated structure having an opening, heating means for heating said oven cavity, and controlling means for controlling said heating means to obtain various temperature combinations in the oven cavity in the cooking range of about 150* F. to 550* F. and in a cleaning range in excess of about 750* F. but less than about 1,200* F., the improvement comprising four transparent panels secured in said opening in said heat-insulated structure in spaced substantially parallel relation, including a first transparent panel, a second transparent panel adjacent said first panel and separated from said oven cavity by said first panel, a third transparent panel separated from said first panel by said second panel, and a fourth transparent panel located between said second and third panels;

means essentially sealing the space between said first and second panels to provide a dead-air space therebetween;

a thin semitransparent reflective coating on the outermost surface of said second panel, said coating formed of a substantially nonchemically reactive metal having a thermal conductivity in excess of about 40 B.t.u./(ft.2hr. * F./in.) at 212* F. and a surface emissivity less than about 0.50 throughout the temperature range between about 750* F. and 950* F.;

a cool air intake at the bottom of the space housing said reflective coating; and

a warm air outlet at the top of the space housing said reflective coating so that when heat escapes from said oven cavity past the dead-air space between said first and second panels, substantial amounts of said escaping heat impinge upon the innermost surface of said reflective coating, portions of which are reflected back toward said cavity and other portions of which are absorbed by said coating, the outermost surface of said coating being cooled by the flow of air across it from said air intake to said air outlet to maintain the outermost exposed surface of the outermost transparent panel at a temperature below 265* F.