Conveyor oven with hybrid heating sources
First Claim
Patent Images
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 energy;
a second, gas-fired burner, which provides infrared energy across a spectrum of different infrared wavelengths the gas-fired burner comprised of;
a burner plate screen below which a gas/fuel mixture at least partially combusts and which heats the burner plate screen, said burner plate screen configured to emit infrared energy, emitted infrared energy having a wavelength corresponding to the burner plate screen temperature;
a conveyor that extends between the first opening and the second opening and which is between the first burner and the second burner;
a gas valve, coupled between a gas source and the gas-fired burner; and
a controller, operatively coupled to the gas valve, the controller being configured to control gas flow through the gas valve in order to cycle the burner plate screen temperature within a range of temperatures, the burner plate screen emitting correspondingly different maximum infrared energy intensities within the range of temperatures, the controllably cycled temperature of the burner plate thereby sweeping a food item with a continuously varying spectrum of infrared energy having maximum infrared energy intensities at wavelengths that are between about 1.0 and about 4.5 micrometers.
6 Assignments
0 Petitions
Accused Products
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.
100 Citations
13 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 energy; a second, gas-fired burner, which provides infrared energy across a spectrum of different infrared wavelengths the gas-fired burner comprised of; a burner plate screen below which a gas/fuel mixture at least partially combusts and which heats the burner plate screen, said burner plate screen configured to emit infrared energy, emitted infrared energy having a wavelength corresponding to the burner plate screen temperature; a conveyor that extends between the first opening and the second opening and which is between the first burner and the second burner; a gas valve, coupled between a gas source and the gas-fired burner; and a controller, operatively coupled to the gas valve, the controller being configured to control gas flow through the gas valve in order to cycle the burner plate screen temperature within a range of temperatures, the burner plate screen emitting correspondingly different maximum infrared energy intensities within the range of temperatures, the controllably cycled temperature of the burner plate thereby sweeping a food item with a continuously varying spectrum of infrared energy having maximum infrared energy intensities at wavelengths that are between about 1.0 and about 4.5 micrometers. - View Dependent Claims (2)
-
-
3. 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, the combustion of the gas/fuel mixture heating the burner plate screen to at least one temperature at which the burner plate screen emits infrared energy, said burner plate screen emitting infrared energy at wavelengths corresponding to the burner plate screen temperature; an electrically-operated gas valve, coupled between a gas source and the at least one gas-fired burner; a controller, operatively coupled to the electrically-operated gas valve and coupled to an igniter, the controller controllably sweeping the range of infrared wavelengths emitted from the burner plate screen by cycling the gas supply on and off and igniting the gas in order to controllably cycle the temperature of the burner plate screen between first and second temperatures, at which the burner plate screen emits infrared energy at correspondingly different wavelengths, the first temperature being such that the wavelength of the maximum emitted infrared is about 4.5 micrometers, the second temperature being such that the wavelength of the maximum emitted infrared is about 1.0 micrometer. - View Dependent Claims (4, 5, 6)
-
-
7. 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 of controllably varying wavelengths 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 wavelengths of infrared heat emitted from the pulsed, gas-fired burner by periodically and repeatedly cycling the gas supply on and off, responsive to an input from the controller in response to an input received by the controller from the user input control panel; wherein the gas supply is turned on for a first time period during which the gas combusts in order to raise the temperature of the burner plate screen to a first temperature at which the burner plate screen emits a first peak wavelength of infrared energy; and wherein, after the expiration of the first time period, the gas supply is turned off for a second time period during which the burner plate screen cools from the first temperature to a second temperature, emitting increasingly longer peak wavelengths of infrared as the burner plate screen cools from the first temperature to the second temperature; wherein after the expiration of the second time period, the gas supply is turned on again for the first time period in order to raise the burner plate screen temperature to said first temperature again; wherein the gas supply is repeatedly turned on and off for the first and second periods to thereby controllably sweep a food item with continuously varying peak wavelengths of infrared energy, the peak wavelengths of emitted infrared varying between about 1.0 micrometer and about 4.5 micrometers. - View Dependent Claims (8, 9)
-
-
10. 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; 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 peak of which vary continuously with said first and second temperatures between about 1 micrometer and about 4.5 micrometers.
-
-
11. 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 energy across a spectrum of different infrared wavelengths the gas-fired burner comprised of; a burner plate screen below which a gas/fuel mixture at least partially combusts and which heats the burner plate screen, said burner plate screen configured to emit infrared energy, emitted infrared energy having a wavelength corresponding to the burner plate screen temperature; a conveyor that extends between the first opening and the second opening and which is between the first burner and the second burner; a gas valve, coupled between a gas source and the gas-fired burner; and a controller, operatively coupled to the gas valve, the controller being configured to control gas flow through the gas valve in order to cycle the burner plate screen temperature, between first and second temperatures, the burner plate screen emitting correspondingly different wavelengths of infrared energy at the first and second temperatures and at temperatures there between, the controllably cycled temperature of the burner plate thereby sweeping a food item with a continuously varying spectrum of infrared energy, the infrared energy emitted at the first temperature being of a long peak wavelength and penetrating foods to a shallow depth, the infrared energy emitted at the second temperature being of a short peak wavelength and penetrating foods more deeply than the long peak wavelength infrared, wherein the long peak wavelength is about 4.5 micrometers and wherein the short peak wavelength is about 1.0 micrometer.
-
-
12. An oven, comprising:
-
a gas-fired burner that is operative to provide infrared energy across a spectrum of different infrared wavelengths, the gas-fired burner comprised of; a burner plate screen below which a gas/fuel mixture at least partially combusts and which heats the burner plate screen, said burner plate screen configured to emit infrared energy corresponding to the burner plate screen temperature; and a controller that is operative to vary the burner plate screen temperature within a temperature range having a maximum infrared energy at a wavelength between 1.0 and 4.5 micrometers. - View Dependent Claims (13)
-
Specification