CONVEYOR OVEN WITH HYBRID HEATING SOURCES

• US 20080264406A1
• Filed: 04/24/2007
• Published: 10/30/2008
• Est. Priority Date: 04/24/2007
• Status: Active Grant

• Current Assignee: Prince Castle LLC (Berkshire Hathaway Incorporated)
• Original Assignee: Prince Castle LLC (Berkshire Hathaway Incorporated)
• Inventors: BURTEA, Sanda, AGNELLO, Frank Anthony, BURTEA, Constantin, VAN ERDEN, Don
• Granted Patent: US 7,800,023 B2
• Time in Patent Office: Days
• US Class Current: 126/39BA
• CPC Class Codes: A21B 1/02 characterised by the heating arrangements
• CPC Class Codes: A21B 1/48 with surfaces in the form of an endless band
• CPC Class Codes: A21B 2/00 Baking apparatus employing high-frequency or infrared heating

Abstract

A conveyor oven is provided with both electric and gas-fired infrared heaters. The heat output from the gas fired infrared heater is controlled by cycling or pulsing the gas supply to one or more burners that emit infrared heat by heating a nichrome screen wire.

Claims

1. An oven comprising:

a cavity having a top, a bottom, a first opening and a second opening;

a first electrically-powered burner which provides infrared heat;

a second gas-fired burner, which provides infrared heat; and

a conveyor that extends between the first opening and the second opening and which is between the first burner and the second burner.

2. The oven of claim 1 wherein the gas fired burner is comprised of:

at least one wire mesh burner plate having first and second spaced-apart, wire mesh burner plates, above which a gas/fuel mixture combusts; and

a burner plate screen spaced above and extending over the at least one wire mesh burner plate and below which the gas/fuel mixture at least partially combusts, said burner plate screen emitting infrared energy.

3. The oven of claim 2 further comprising:

a gas valve, coupled between a gas source and the gas-fired burner; and

a controller, operatively coupled to the gas valve, the controller controlling the amount of infrared heat emitted from the burner plate screen by cycling the gas supply on and off.

5. The oven of claim 1 wherein the second burner is located at the top of the oven and projects infrared heat downwardly.

4. The oven of claiming 1 wherein the first burner is located at the top of the oven and projects infrared heat downwardly.

6. An oven comprising:

a cavity having a top, a bottom, a first opening and a second opening;

a conveyor that extends between the first opening and the second opening;

at least one gas-fired burner within the cavity and which directs infrared heat toward the conveyor, the at least one gas fired burner comprised of;

at least one wire mesh burner plate comprised of first and second, substantially parallel, spaced-apart wire mesh burner plates, above which a gas/fuel mixture combusts;

a burner plate screen spaced above and extending over the at least one wire mesh burner plate and below which the gas/fuel mixture at least partially combusts, said burner plate screen emitting infrared energy after being heated by the gas/fuel mixture combustion.

7. The oven of claim 6 further comprised of at least one electrically powered infrared heater above the conveyor and which projects infrared beat toward the conveyor.

8. The oven of claim 6, wherein the at least one gas-fired burner is at the bottom of the oven, below the conveyor and projects infrared upwardly and toward the first electrically powered infrared heater.

9. The oven of claim 6 wherein the at least one gas-fired burner is at the top of the oven, above the conveyor and projects infrared heat downwardly.

10. The oven of claim 6 further comprising:

an electrically-operated gas valve, coupled between a gas source and the gas-fired burner; and

a controller, operatively coupled to the gas valve and an igniter, the controller controlling the amount of infrared heat emitted from the burner plate screen by cycling the gas supply on and off.

11. An oven comprising:

a cavity having a top, a bottom, a first opening and a second opening;

a conveyor that extends between the first opening and the second opening;

a first electrically powered infrared heater, which directs infrared heat toward the conveyor;

a pulsed, gas-fired burner within the cavity and which directs infrared heat toward the conveyor, the pulsed gas fired burner comprised of;

at least one wire mesh burner plate comprised of first and second, substantially parallel, spaced-apart wire mesh burner plates, above which a gas/fuel mixture combusts;

a burner plate screen spaced above and extending over the at least one wire mesh burner plate and below which the gas/fuel mixture at least partially combusts, said burner plate screen emitting infrared energy after being heated by the gas/fuel mixture combustion; and

an electrically-operated gas valve, coupled between a gas source and the gas-fired burner;

a user input control panel;

a controller, operatively coupled to the user input control panel and to the gas valve, the controller controlling the amount of infrared heat emitted from the second heating source by periodically cycling the gas supply on and off in response to signals received from the user input control panel.

12. The oven of claim 11 wherein the controller cycles the gas supply for an on time of between about five seconds and about sixty seconds.

13. The oven of claim 11 wherein the at least one gas-fired burner is at the top of the oven, above the conveyor and projects infrared heat downwardly.

14. An oven comprising:

a cavity having a top, a bottom, a first opening and a second opening;

a conveyor that extends between the first opening and the second opening;

at least one gas-fired burner within the cavity and which directs infrared heat toward the conveyor, the at least one gas fired burner comprised off;

at least one wire mesh burner plate;

a burner plate screen spaced above and extending over the at least one wire mesh burner plate and below which the gas/fuel mixture at least partially combusts;

wherein fuel gas to the burner is controllably cycled on and off in order to cause the temperature of the burner plate screen to fluctuate between first and second temperatures, said burner plate screen thereby emitting IR, the wavelengths of which vary continuously with said first and second temperatures.