Radiant tunnel

Claim 2

A food product cooking device comprising in combination: means defining an open ended horizontally elongated tunnel; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product lengthwise through said tunnel; first and second metal screen devices arranged within said tunnel in a spaced essentially parallel relationship with lower and upper surfaces of said conveyor run, respectively, one marginal edge of said conveyor run extending transversely beyond said lower screen device to define an overhang extending lengthwise of said conveyor run; and heater means for heating said screen devices to within a range at which said screen devices emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said heater means including a main gas heater arranged to direct a flame upwardly towards a lower surface of said first screen device and a secondary gas heater arranged to direct a flame upwardly towards said second screen device through said conveyor run overhang.

Claim 3

A device according to claim 1, wherein said tunnel includes an exhaust opening extending lengthwise thereof above said second screen device adjacent a marginal edge of said conveyor run opposite from said overhang, and refractory material is arranged to overlie said second screen device and at least partially bounds a passageway communicating with said exhaust opening.

Claim 4

A device according to claim 2, wherein said first screen device is coarsely woven and of light weight relative to said second screen device.

Claim 5

A food product cooking device comprising in combination: means defining an open ended tunnel, said tunnel being horizontally elongated and including a pair of lengthwise extending side walls, a top wall means joining said side walls and defining an elongated exhaust port extending lengthwise of said tunnel adjacent one of said side walls, and lengthwise extending support means arranged adjacent another of said side walls; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product through said tunnel; first and second metal screen devices, said side walls having support flanges for supporting lengthwise extending marginal edges of said second screen device whereby to support said second screen device in an essentially horizontally disposed relationship vertically below said top wall means in a spaced essentially parallel relationship with an upper surface of said conveyor run, said one side wall and said support means having support flanges for supporting lengthwise extending marginal edges of said first screen device whereby to support said first screen device in a spaced essentially parallel relationship with a lower surface of said conveyor run; and heater means for heating said screen devices to within a range at which said screen devices emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said heater means including a main gas heater arranged intermediate said one side wall and said support means for directing a flame upwardly towards a lower surface of said first screen device and a second gas heater arranged intermediate said support means and said other side wall for directing a flame upwardly towards a lower surface of said second screen device, and said top wall means includes refractory material disposed immediately above said second screen device and spaced from said one side wall to define a flow opening in vertical alignment with said exhaust port.

Claim 6

A food product cooking device comprising in combination: means defining an open ended tunnel, said tunnel being horizontally elongated and including a pair of lengthwise extending side walls, a top wall means joining said side walls and defining an elongated exhaust port extending lengthwise of said tunnel adjacent one of said side walls, and lengthwise extending support means arranged adjacent another of said side walls; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product through said tunnel; first and second metal screen devices, said side walls having support flanges for supporting lengthwise extending marginal edges of said second screen device whereby to support said second screen device in an essentially horizontally disposed relationship vertically below said top wall means in a spaced essentially parallel relationship with an upper surface of said conveyor run, said one side wall and said support means having support flanges for supporting lengthwise extending marginal edges of said first screen device whereby to support said first screen device in a spaced essentially parallel relationship with a lower surface of said conveyor run; and heater means for heating said screen devices to within a range at which said screen devices emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said heater means including a main gas heater arranged intermediate said one side wall and said support means for directing a flame upwardly towards a lower surface of said first screen device and a second gas heater arranged intermediate said support means and said other side wall for directing a flame upwardly towards a lower surface of said second screen device, and said top wall means includes refractory material disposed immediately above said second screen device and spaced from said one side wall to define a flow opening in vertical alignment with said exhaust port.

Claim 7

A device according to claim 4, wherein said first screen device is coarsely woven and of light weight relative to said second screen device.

Claim 8

A food product cooking device comprising in combination: means defining an open ended tunnel, said tunnel being horizontally elongated and including a pair of lengthwise extending side walls, a top wall joining said side walls and defining an elongated exhaust port extending lengthwise of said tunnel adjacent one of said side walls, lengthwise extending support wall arranged adjacent another of said side walls; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product through said tunnel; first and second metal screen devices, said first screen device being more coarsely woven and of lighter weight than said second screen device, said side walls having support flanges adjacent upper marginal edges thereof for supporting lengthwise extending marginal edges of said second screen device whereby to support said second screen device in an essentially horizontally disposed relationship vertically below said top wall in a spaced essentially parallel relationship with an upper surface of said conveyor run, said one side wall having a support flange intermediate said marginal edges thereof and said support wall having a support flange adjacent an upper marginal edge thereof for supporting lengthwise extending marginal edges of said first screen device whereby to support said first screen device in a spaced essentially parallel relationship with a lower surface of said conveyor run; heater means for heating said screen devices to within a range at which said screen devices emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said heater means being mounted on said tunnel by means extending transversely of said tunnel adjacent lower marginal edges of said side and support walls, said heater means including a main gas burner arranged intermediate said one side wall and said support wall for directing a flame upwardly towards a lower surface of said first screen device and a secondary gas burner arranged intermediate said support wall and said other side wall for directing a flame upwardly towards a lower surface of said second screen device; and refractory material supported on said second screen device and spaced from said one side wall to define a flow opening in vertical alignment with said exhause port, said refractor material tending to constrain products of combustion from said heater means for passage through said second screen device substantially only in an area in vertical alignment with said flow opening.

Claim 9

A food product cooking device comprising in combination: means defining an open ended tunnel, said tunnel being horizontally elongated and including a pair of lengthwise extending side walls, a top wall joining said side walls and defining an elongated exhaust port extending lengthwise of said tunnel adjacent one of said side walls, lengthwise extending support wall arranged adjacent another of said side walls; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product through said tunnel; first and second metal screen devices, said first screen device being more coarsely woven and of lighter weight than said second screen device, said side walls having support flanges adjacent upper marginal edges thereof for supporting lengthwise extending marginal edges of said second screen device whereby to support said second screen device in an essentially horizontally disposed relationship vertically below said top wall in a spaced essentially parallel relationship with an upper surface of said conveyor run, said one side wall having a support flange intermediate said marginal edges thereof and said support wall having a support flange adjacent an upper marginal edge thereof for supporting lengthwise extending marginal edges of said first screen device whereby to support said first screen device in a spaced essentially parallel relationship with a lower surface of said conveyor run; heater means for heating said screen devices to within a range at which said screen devices emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said heater means being mounted on said tunnel by means extending transversely of said tunnel adjacent lower marginal edges of said side and support walls, said heater means including a main gas burner arranged intermediate said one side wall and said support wall for directing a flame upwardly towards a lower surface of said first screen device and a secondary gas burner arranged intermediate said support wall and said other side wall for directing a flame upwardly towards a lower surface of said second screen device; and refractory material supported on said second screen device and spaced from said one side wall to define a flow opening in vertical alignment with said exhause port, said refractor material tending to constrain products of combustion from said heater means for passage through said second screen device substantially only in an area in vertical alignment with said flow opening.

Claim 10

A device according to claim 6, wherein valve means are provided to adjust the flow of combustible gas to said heater means, and sensor means are arranged to sense the temperature of said products of combustion passing through said exhaust port, said sensor means controlling said valve means to vary flow of combustible gas to said heater means inversely relative to sensed temperature.

Claim 11

A food product cooking device comprising in combination: means defining an open ended horizontally elongated tunnel, said tunnel having an elongated exhaust port extending along one side thereof; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product lengthwise through said tunnel; first and second metal screen devices arranged within said tunnel in a spaced essentially parallel relationship with lower and upper surfaces of said conveyor run, respectively, said second screen device extending horizontally transversely beyond said first screen device along a side of said tunnel spaced from said one side; and gas heater means for heating said screens to within a range at which said screens emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said gas heater means being Disposed relatively below said first screen device and arranged to apply a flame to a lower surface of said first screen device and to a lower surface of said second screen device in that area thereof extending beyond said first screen device.

Claim 12

A food product cooking device comprising in combination: means defining an open ended horizontally elongated tunnel, said tunnel having an elongated exhaust port extending along one side thereof; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product lengthwise through said tunnel; first and second metal screen devices arranged within said tunnel in a spaced essentially parallel relationship with lower and upper surfaces of said conveyor run, respectively, said second screen device extending horizontally transversely beyond said first screen device along a side of said tunnel spaced from said one side; and gas heater means for heating said screens to within a range at which said screens emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said gas heater means being Disposed relatively below said first screen device and arranged to apply a flame to a lower surface of said first screen device and to a lower surface of said second screen device in that area thereof extending beyond said first screen device.

Claim 13

A food product cooking device according to claim 8, wherein said gas heater means includes a main heater means extending lengthwise of said tunnel beneath said first screen device and a secondary heater means extending lengthwise of said tunnel beneath said area of said second screen device extending beyond said first screen device.

Claim 14

A food product cooking device according to claim 9, wherein said first screen device is coarsely woven and of light weight relative to said second screen device.

Claim 15

A food product cooking device comprising in combination: means defining an open ended horizontally elongated tunnel, said tunnel having a vertically opening, elongated exhaust port extending along one side thereof; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product lengthwise through said tunnel; first and second metal screen devices arranged within said tunnel in a spaced essentially parallel relationship with lower and upper surfaces of said conveyor run, respectively, said first screen device being coarsely woven and of light weight relative to said second screen device; and heater means for heating said screens to within a range at which said screens emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said heater means including a main gas heater arranged to apply a flame to a lower surface of said first screen device and a secondary gas heater arranged to apply a flame to a lower surface of said second screen device along a marginal portion thereof extending along a side of said tunnel spaced transversely from said one side, said tunnel tending to constrain products of combustion from said heater means for passage through said second screen device substantially only in an area thereof in alignment with said exhaust port.

Claim 16

A food product cooking device comprising in combination: means defining an open ended horizontally elongated tunnel, said tunnel having a vertically opening, elongated exhaust port extending along one side thereof; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product lengthwise through said tunnel; first and second metal screen devices arranged within said tunnel in a spaced essentially parallel relationship with lower and upper surfaces of said conveyor run, respectively, said first screen device being coarsely woven and of light weight relative to said second screen device; and heater means for heating said screens to within a range at which said screens emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said heater means including a main gas heater arranged to apply a flame to a lower surface of said first screen device and a secondary gas heater arranged to apply a flame to a lower surface of said second screen device along a marginal portion thereof extending along a side of said tunnel spaced transversely from said one side, said tunnel tending to constrain products of combustion from said heater means for passage through said second screen device substantially only in an area thereof in alignment with said exhaust port.

Claim 17

A food product cooking device comprising in combination: means defining an open ended horizontally elongated tunnel, said tunnel having a pair of lengthwise extending side walls, a top wall means joining said side walls and defining an elongated exhaust port extending lengthwise of said tunnel; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product lengthwise through said tunnel; first and second metal screen devices arranged within said tunnel in a spaced essentially parallel relationship with lower and upper surfaces of said conveyor run, respectively, said first screen being coarsely woven and of light weight relative to said second screen device; and gas heater means for heating said screens to within a range at which said screens emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said heater means including a gas heater arranged to apply a flame to a lower surface of said first screen device and another gas heater arranged to apply a flame to a lower surface of said second screen device along a marginal portion thereof extending lengthwise of said tunnel, said top wall means including refractory material disposed to rest on said second screen device and tending to constrain products of combustion from said heater means for passage through said second screen device substantially only in an area thereof in vertical alignment with said exhaust port, and said area of said second screen device being spaced transversely of said tunnel from said marginal portion thereof.

Claim 18

A food product cooking device comprising in combination: means defining an open ended horizontally elongated tunnel, said tunnel having a pair of lengthwise extending side walls, a top wall means joining said side walls and defining an elongated exhaust port extending lengthwise of said tunnel; an endless open grid type belt conveyor having a horizontally disposed supporting run arranged to transport said food product lengthwise through said tunnel; first and second metal screen devices arranged within said tunnel in a spaced essentially parallel relationship with lower and upper surfaces of said conveyor run, respectively, said first screen being coarsely woven and of light weight relative to said second screen device; and gas heater means for heating said screens to within a range at which said screens emit substantial infra red radiation, whereby to impart heat to said food product during transport thereof through said tunnel, said heater means including a gas heater arranged to apply a flame to a lower surface of said first screen device and another gas heater arranged to apply a flame to a lower surface of said second screen device along a marginal portion thereof extending lengthwise of said tunnel, said top wall means including refractory material disposed to rest on said second screen device and tending to constrain products of combustion from said heater means for passage through said second screen device substantially only in an area thereof in vertical alignment with said exhaust port, and said area of said second screen device being spaced transversely of said tunnel from said marginal portion thereof.