Self-cleaning gas oven with heat exchanger

Claim 2

A gas oven comprising an oven body supporting a boxlike oven liner and a front-opening access door which define an oven cooking cavity, a firebox disposed beneath the bottom wall of the oven liner, a bake burner means located within the firebox, heating channels extending from the firebox around the outside of the oven liner so that convection currents of flue gases from the bake burner means may pass through the channels so as to heAt the oven liner, a heat exchanger mounted in the oven body and having adjacent one end a flue gas inlet from the heating channels and a flue gas outlet adjacent the other end as well as an ambient air inlet adjacent the flue gas outlet and an ambient air outlet communicating with the firebox, said ambient air outlet supplying heated air to the firebox as preheated secondary air for the bake burner means, additional ambient air openings in the walls of the firebox for supplying secondary air to the bake burner means during a preheat period of the heating cycle while the heat exchanger is operating relatively cold and the burner means is incapable of drawing the ambient air through the heat exchanger, and normally open temperature-responsive closure means cooperating with the said ambient air openings to close said openings after the firebox reaches a predetermined temperature whereupon preheated secondary air is furnished to the bake burner means by the heat exchanger.

Claim 3

A gas oven as recited in claim 1 including a broiler burner means located adjacent the top portion of the oven liner as the sole heating means during a broiling operation whereby the said firebox remains relatively cool so as not to operate the said temperature-responsive closure means and thereby allowing the said ambient air openings to remain open, second air openings in the bottom portion of the oven liner, an oven vent means in the top portion of the oven liner, and second closure means for closing the oven vent means during normal baking and high-temperature heat-cleaning operations while being held open during broiling operations, so that broiling may be accomplished with the oven door closed, whereby secondary air for the broiler burner means enters the firebox through the ambient air openings and enters the oven liner through the said second air openings and after passing over the broiler burner means exits through the said oven vent means.

Claim 4

A self-cleaning gas-fired cooking oven comprising an oven body supporting a boxlike inner oven liner and a front-opening access door which define an oven cooking cavity, and an outer oven liner surrounding the inner oven liner and spaced therefrom to form a firebox beneath the inner oven liner as well as heating channels around the inner oven liner, and bake burner means within the firebox to cause convection current of flue gases to pass around the inner oven liner for heating the walls thereof during both baking and heat-cleaning operations, and a vertically arranged stationary heat exchanger located adjacent at least one wall of the outer oven liner, and flue gas inlet openings in the bottom of the heat exchanger communicating with the said heating channels, and flue gas outlet means in the top portion of the heat exchanger, and ambient air inlet means adjacent the top portion of the heat exchanger and heated air outlet means adjacent the bottom portion of the heat exchanger communicating with the firebox as a source of preheated secondary air for the bake burner means, second ambient air openings in the firebox, and normally open temperature-responsive closure means associated with the said second ambient air openings and adapted to close said openings after the temperature within the firebox reaches a predetermined temperature thereby furnishing an initial source of secondary air for the bake burner means while the heat exchanger is in a relatively cool condition when the bake burner means is incapable of drawing the ambient air supply down through the heat exchanger, the heated air supply from the heat exchanger being established prior to the closure of the second ambient air openings.

Claim 5

A self-cleaning gas-fired cooking oven comprising an oven body supporting a boxlike inner oven liner and a front-opening access door which define an oven cooking cavity, and an outer oven liner surrounding the inner oven liner and spaced therefrom to form a firebox beneath the inner oven liner as well as heating channels around the inner oven liner, and bake burner means within the firebox to cause convection current of flue gases to pass around the inner oven liner for heating the walls thereof during both baking and heat-cleaning operations, and a vertically arranged stationary heat exchanger located adjacent at least one wall of the outer oven liner, and flue gas inlet openings in the bottom of the heat exchanger communicating with the said heating channels, and flue gas outlet means in the top portion of the heat exchanger, and ambient air inlet means adjacent the top portion of the heat exchanger and heated air outlet means adjacent the bottom portion of the heat exchanger communicating with the firebox as a source of preheated secondary air for the bake burner means, second ambient air openings in the firebox, and normally open temperature-responsive closure means associated with the said second ambient air openings and adapted to close said openings after the temperature within the firebox reaches a predetermined temperature thereby furnishing an initial source of secondary air for the bake burner means while the heat exchanger is in a relatively cool condition when the bake burner means is incapable of drawing the ambient air supply down through the heat exchanger, the heated air supply from the heat exchanger being established prior to the closure of the second ambient air openings.

Claim 6

A domestic cooking oven as recited in claim 3 with a broiler burner means positioned adjacent the upper portion of the inner oven liner, and openings in the bottom portion of the oven liner communicating with the firebox, and a normally closed oven vent means for the cooking cavity adjacent the top portion of the inner oven liner, whereby closed door broiling may be performed in the oven by first opening the oven vent means and operating the broiler burner means such that secondary air for this burner means enters the firebox through the said second ambient air openings and passes into the cooking cavity through the openings in the bottom of the inner oven liner for sweeping over the broiler burner means and exhausting through the oven vent means.

Claim 7

A self-cleaning gas oven comprising an outer supporting structure, an inner layer of thermal insulating material protecting the supporting structure, a boxlike outer oven liner positioned within the thermal insulating material, an inner oven liner positioned within the outer oven liner and spaced therefrom to form a firebox beneath the inner oven liner and heating channels around at least a major portion of the inner oven liner, a bake burner located within the firebox, whereby hot flue gases from the burner means pass through the heating channels for raising the temperature of the walls of the inner oven liner for normal cooking operations as well as for high-temperature heat-cleaning operations, and heat exchanger means mounted across at least one vertical wall of the outer oven liner, said firebox having air inlet means communicating with the heat exchanger, the lower portion of said vertical wall having flue gas outlet means from the heating channels communicating with the heat exchanger, the upper portion of the heat exchanger having an ambient air inlet means and flue gas outlet means whereby the heat exchanger causes the flue gases to be cooled before they are released from the oven and the air supply to the firebox to become preheated secondary air for the bake burner means; the invention comprising an auxiliary secondary air supply means for the bake burner means for use when the temperature within the firebox is not high enough to create a draft strong enough to draw the ambient air down through the heat exchanger, said auxiliary air supply means comprising second ambient air openings in the firebox, and normally open temperature responsive damper means cooperating with the said second ambient air openings and serving to close said second openings when the firebox temperature reaches a predetermined level.

Claim 8

A self-cleaning gas oven comprising an outer supporting structure, an inner layer of thermal insulating material protecting the supporting structure, a boxlike outer oven liner positioned within the thermal insulating material, an inner oven liner positioned within the outer oven liner and spaced therefrom to form a firebox beneath the inner oven liner and heating channels around at least a major portion of the inner oven liner, a bake burner located within the firebox, whereby hot flue gases from the burner means pass through the heating channels for raising the temperature of the walls of the inner oven liner for normal cooking operations as well as for high-temperature heat-cleaning operations, and heat exchanger means mounted across at least one vertical wall of the outer oven liner, said firebox having air inlet means communicating with the heat exchanger, the lower portion of said vertical wall having flue gas outlet means from the heating channels communicating with the heat exchanger, the upper portion of the heat exchanger having an ambient air inlet means and flue gas outlet means whereby the heat exchanger causes the flue gases to be cooled before they are released from the oven and the air supply to the firebox to become preheated secondary air for the bake burner means; the invention comprising an auxiliary secondary air supply means for the bake burner means for use when the temperature within the firebox is not high enough to create a draft strong enough to draw the ambient air down through the heat exchanger, said auxiliary air supply means comprising second ambient air openings in the firebox, and normally open temperature responsive damper means cooperating with the said second ambient air openings and serving to close said second openings when the firebox temperature reaches a predetermined level.

Claim 9

A self-cleaning gas oven as recited in claim 5 with a broiler burner means located in the upper portion of the inner oven liner, openings through the bottom portion of the inner oven liner communicating with the firebox, an oven vent means in the upper portion of the inner oven liner, and normally closed cover means cooperating with the oven vent means, whereby closed door broiling operations may be performed in the oven when the said cover means is opened and the broiler burner means is operated so that secondary air flow is created for the broiler burner means with air entering the said second ambient air openings and rising through the firebox and passing through the openings in the bottom portion of the inner oven liner and passing around the broiler burner means and exhausting through the said oven vent means.

Claim 10

A self-cleaning gas oven comprising an outer supporting structure, an inner layer of thermal insulating material within the supporting structure, a boxlike oven liner positioned within the insulated oven structure, a firebox positioned beneath the oven liner, bake burner means within the firebox, and heating channels associated with at least a major portion of the walls of the oven liner and communicating with the firebox whereby hot flue gases from the bake burner means pass through the heating channels in the manner of a muffle oven for raising the temperature of the walls of the oven liner for normal baking operations as well as for high-temperature heat-cleaning operations, and heat exchanger means associated with the oven for receiving the flue gases and cooling them down before the gases are exhausted from the oven, the heat exchanger means using ambient air as a coolant means, said air becoming heated in the process of cooling the flue gases and being fed into the firebox as preheated secondary air for the bake burner means, an auxiliary secondary air supply means for the bake burner means for use when the temperature within the firebox is below a predetermined temperature, said auxiliary supply means comprising ambient air openings in the firebox, and normally open temperature-responsive damper means cooperating with the said ambient air opening and serving to close said air openings when the firebox temperature reaches a predetermined level, and broiler burner means located in the upper portion of the oven liner, openings through the bottom portion of the oven liner, oven vent means in the upper portion of the oven liner, and normally closed cover means to cooperate with the oven vent means whereby closed door broiling operations may be performed in the oven when the said cover means is opened and the broiler burner means is operated so that a secondary airflow is created for the broiler burner means by air passing through the said ambient air openings in the firebox, then through the openings in the bottom portion of the oven liner, over the broiler burner means and exhausting through the oven vent means.

Claim 11

A self-cleaning gas oven comprising an outer supporting structure, an inner layer of thermal insulating material within the supporting structure, a boxlike oven liner positioned within the insulated oven structure, a firebox positioned beneath the oven liner, bake burner means within the firebox, and heating channels associated with at least a major portion of the walls of the oven liner and communicating with the firebox whereby hot flue gases from the bake burner means pass through the heating channels in the manner of a muffle oven for raising the temperature of the walls of the oven liner for normal baking operations as well as for high-temperature heat-cleaning operations, and heat exchanger means associated with the oven for receiving the flue gases and cooling them down before the gases are exhausted from the oven, the heat exchanger means using ambient air as a coolant means, said air becoming heated in the process of cooling the flue gases and being fed into the firebox as preheated secondary air for the bake burner means, an auxiliary secondary air supply means for the bake burner means for use when the temperature within the firebox is below a predetermined temperature, said auxiliary supply means comprising ambient air openings in the firebox, and normally open temperature-responsive damper means cooperating with the said ambient air opening and serving to close said air openings when the firebox temperature reaches a predetermined level, and broiler burner means located in the upper portion of the oven liner, openings through the bottom portion of the oven liner, oven vent means in the upper portion of the oven liner, and normally closed cover means to cooperate with the oven vent means whereby closed door broiling operations may be performed in the oven when the said cover means is opened and the broiler burner means is operated so that a secondary airflow is created for the broiler burner means by air passing through the said ambient air openings in the firebox, then through the openings in the bottom portion of the oven liner, over the broiler burner means and exhausting through the oven vent means.