OVENS, FINGER DUCTS THEREFOR, AND METHODS FOR DISTRIBUTING AIR IN A FINGER DUCT

Abstract

The present invention is directed to ovens for heat treating products and may include food preparation ovens for preparing pizza and similar types of food products. The oven include finger ducts having longitudinally-extending staggered angled air deflectors to aid in distribution of the heated air into the oven.

Description

CLAIM TO PRIORITY AND CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/915,012, filed Apr. 30, 2007, entitled “Ovens, And Burner Tube Assemblies, Cold Air Return Baffles, Finger Ducts, And Removable Wheels Therefor”, which is hereby incorporated herein by reference in its entirety.

This application is related to commonly owned, and co-filed U.S. patent application Ser. No. ______, entitled “Ovens, Burner Tube Assemblies, And Methods For Delivering Air To A Gas Power Burner,” by Bramhall, (Docket No. 2869.015A); U.S. patent application Ser. No ______, entitled “Ovens Having A Cold Air Return Baffle And Methods For Circulating Air In An Oven,” by Bramhall, (Docket No. 2869.015B); and U.S. patent application Ser. No. ______, entitled “Methods For Moving Ovens, And Ovens Having Means For Releasably Attaching To A Plurality Of Casters,” by Bramhall, (Docket No. 2869.015D), which are hereby incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates generally to ovens, and more specifically, to finger ducts for ovens for heat treating products.

BACKGROUND OF THE INVENTION

Ovens for heat-treating products oftentimes employ a burner for combusting a fuel such as gas or an electric means for heating the oven. Food preparation ovens such as food preparation ovens for preparing pizza and other types of food products employ jets of hot gaseous fluid such as hot air for baking or cooking the food product.

FIG. 1 illustrates a portion of a conventional finger duct 10 having a single channel structure 20 and a plurality of deflectors 30. Not shown in FIG. 1 is a diffuser which is disposed on top of the baffles and a cover disposed on top of the diffuser. The cover has a plurality of openings through which the heated gas is discharged toward the surface to be heated. Pressurized heated air is introduced via an inlet 40.

U.S. Pat. No. 5,025,775 issued to Crisp discloses a finger duct 44a having plurality of scoop-shaped deflector vanes 66a, 66b, 66c, and 66d, each attached to finger duct 44a and extending the width of finger duct 44a. See FIGS. 7 and 9. The front edge of each deflector 66 is perpendicular to inner nozzle plate 54a, and the back edge 70 is outwardly curved and attached to finger duct 44a. As air flows through finger duct 44a, it tends to flow through the entire length of the duct and exit through nozzles 48 which are near the end of finger duct 44a. Deflectors 66 provide a more uniform distribution of air flow from front to back by deflecting a portion of the air flow nearer the front of finger duct 44a out through nozzle 48. In addition to providing a more uniform distribution of air flow, deflectors 66 redirect the flow of air without creating high and low pressures within finger duct 44a.

U.S. Pat. No. 6,192,877 issued to Moshonas et al. disclose a blown air distributor for a convection oven. The blown air distributors comprises a plurality of finger ducts mounted in parallel on a single plate having opposite side edges each slidably receivable in a guide way provided on a corresponding side wall of the baking chamber. The blown air distributor has an adjustable deflector in each finger duct to control a flow of heated air therein. Preferably, each of the adjustable deflector comprises an inclined baffle wall having two opposite side edges secured to a corresponding sidewall of the finger duct. The baffle wall has a back end extending towards the inlet of the finger duct and a front end extending towards a front end wall of the finger duct. A controllable plate having an end hinged to the back end of the baffle wall is also provided. The controllable plate is pivotable between a downward position where most of the heated air received through the inlet of the finger duct is directed towards the front end wall of the finger duct and an upward position where most of the heated air received through the inlet of the finger duct is directed generally under the baffle wall. The plate is controllable by means of an operating handle mounted on an outer surface of the finger duct and operatively connected to the controllable plate to pivot the plate between the downward and the upward position.

U.S. Pat. No. 6,526,961 issued to Hardenburger discloses a conveyor oven having lower, middle and upper hot air manifold fingers. The middle finger has a lower air plate with air holes, an upper air plate with air holes, and an internal baffle. The internal baffle has a series of holes that allow about ⅓ of the air flow to this finger to travel downward and out through the lower air plate.

There is a need for further ovens and finger ducts therefore.

SUMMARY OF THE INVENTION

The present invention, in a first aspect, is directed to a finger duct for directing heated air in an oven. The finger duct includes an elongated housing an having inlet at one end of the housing for receiving a flow of heated air, and a plurality of outlets spaced generally along a length of the housing for directing heated air towards a surface to be heated in the oven. At least one elongated divider is disposed in and along the length of the housing to define at least a plurality of longitudinally-extending channels in the housing. A plurality of spaced-apart angled deflectors is disposed in a staggered pattern in the plurality of longitudinally-extending channels for directing the heated air towards the plurality of openings.

The present invention, in a second aspect, is directed to an oven for heat treating a product. The oven includes a housing having a front sidewall, a rear sidewall, a right sidewall, a left sidewall, a top, a bottom, and an interior wall extending between the right sidewall and the left sidewall to define a first chamber and a second chamber in the housing. Means are provided for heating air in the first chamber. An elongated finger duct as described above is in fluid communication with the first chamber for receiving heated air from the first chamber and discharging the heated air along a length of the finger duct in a first direction towards a surface to be heated in the second chamber.

The present invention, in a third aspect, is directed to a method for distributing air in a finger duct for use in an oven for heat treating a product. The method includes introducing a flow of heated air into an inlet of the finger duct, dividing the flow of heated air into a plurality of longitudinally-extending channels in the finger duct, staggering the deflection of the flow of air in adjacent ones of the plurality of longitudinally-extending channels toward a plurality of outlets in the finger duct, and discharging the deflected flow of air in each of the plurality of longitudinally-extending channels from respective plurality of outlets in the finger duct.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, may best be understood by reference to the following detailed description of various embodiments and the accompanying drawings in which:

FIG. 1 is a perspective view of a portion of a prior art finger duct;

FIG. 2 is a front perspective view of one embodiment of an oven in accordance with the present invention;

FIG. 3 is diagrammatic side elevational view of a portion of the oven in FIG. 2;

FIG. 4 is an end view of the portion of the oven of FIG. 3;

FIG. 5 is a top view of the portion of the oven of FIG. 3;

FIG. 6 is a perspective view, partially cut-away, of a housing of a finger duct in accordance with the present invention;

FIG. 7 is a view taken along line 7-7 in FIG. 6; and

FIG. 8 is a flowchart of one embodiment of a method for distributing air in a finger duct for use in an oven for heat treating a product.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to ovens for heat treating products and may include ovens for heat treating products such as ovens for preparing pizza and similar types of food products. For example, the ovens may be configured as an impingement oven having a conveyor wherein food products are baked or cooked by means of jets of hot gaseous fluid such as hot air and wherein the hot air jets are impinged directly upon localized areas of the food product.

FIG. 2 illustrates an oven 100 in accordance with the present invention for heat treating products and may include an oven for preparing pizza and similar types of food products. For example, a gas power burner may be used in an impingement oven having a housing 112 and a conveyor 120 wherein food products are baked or cooked by means of jets of hot gaseous fluid such as hot air and wherein the hot air jets are impinged directly upon localized areas of the food product. Alternatively, an electrical heating element may be employed instead of the gas burner. A shroud 130 covers a conveyor drive motor operatively connected via a gear motor, a sprocket, and a chain, for moving the conveyor. It will be appreciated that a plurality of such ovens may be employed in a stacked configuration.

In one aspect, the present invention is directed ovens having an improved finger duct. As best shown in FIGS. 3-5, oven 112 includes a housing having a front sidewall 200, a rear sidewall 210, a right sidewall 220, a left sidewall 230, a top 240, and a bottom 250. An interior wall 260 extends between the right sidewall and the left sidewall to define a first chamber 270 in which air is heated and a second chamber 280 which may include conveyor 120 (FIG. 4) for moving the products to be heat treated through the oven. Finger ducts 330 and 332 discharge heated air from plurality of outlets in the finger ducts.

FIG. 6 illustrates one embodiment of a finger duct 400 in accordance with the present invention. Finger duct 400 includes housing 405, a plurality of longitudinally-extending dividers 410 which define a plurality of narrow longitudinally-extending channels 412, 414, and 416. Disposed in the narrow longitudinally-extending channels is a plurality of staggered angled air deflectors 420. The deflectors may be disposed in a staggered checkered pattern configuration. As shown in FIG. 7, a diffuser 450 may be disposed on top of the staggered deflectors and dividers and a cover 460 of housing 405 having a plurality of outlets 465 may be disposed on top of the diffuser. The deflectors may be placed and sandwiched between the longitudinally-extending channels (need not be welded) and held in place by the diffuser. Pressurized heated air is introduced via inlet 470 (FIG. 6). Deflectors 420 are disposed on an angle, e.g., on angle less than about 45 degrees. Above 45 degrees may result in the air flow stalling. The finger duct having longitudinally-extending dividers and staggered deflectors enhances the airflow exiting the finger duct. The number, spacing, depth, and angle of the deflectors may be optimized so that the pressure and temperature is generally constant over the area to be heated, and/or so that the heated air is generally evenly discharged from the cover of the housing.

FIG. 8 illustrates a flowchart of a method 500 for distributing air in a finger duct for use in an oven for heat treating a product. Method 500 includes at 510, introducing a flow of heated air into an inlet of the finger duct, and at 520, dividing the flow of heated air into a plurality of longitudinally-extending channels in the finger duct. The flow of air in each of the plurality of longitudinally-extending channels is directed toward a plurality of outlets in the finger duct at 530. At 540, the deflected flow of air in each of the plurality of longitudinally-extending channels is discharged from respective plurality of outlets in the finger duct.

The various components of the present invention described above may be incorporated into the food preparation ovens disclosed in U.S. Pat. No. 4,846,143 issued to Csadenyl, U.S. Pat. No. 5,025,775 issued to Crisp, and applicant's co-filed U.S. patent applications as noted above, the entire subject matter of these patents and applications being incorporated herein by reference.

Thus, while various embodiments of the present invention have been illustrated and described, it will be appreciated to those skilled in the art that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

Claims

1. A finger duct for directing heated air in an oven, said finger duct comprising:

an elongated housing having an inlet at one end of the housing for receiving a flow of heated air, and a plurality of outlets spaced generally along a length of the housing for directing heated air towards a surface to be heated in the oven;

at least one elongated divider disposed in and along the length of said housing to define at least a plurality of longitudinally-extending channels in said housing; and

a plurality of spaced-apart angled deflectors disposed in a staggered pattern in said plurality of longitudinally-extending channels for directing the heated air towards the plurality of openings.

2. The finger duct of claim 1 wherein said at least one elongated divider comprises a plurality of elongated dividers to define a plurality of longitudinally-extending channels, and said plurality of angled deflectors comprise a staggered checkered pattern in said plurality of longitudinally-extending channels.

3. The finger duct of claim 1 wherein said plurality of angled deflectors is sandwiched between said divider and said housing in the longitudinally-extending channels.

4. The finger duct of claim 1 wherein said plurality of angled deflectors comprises a plurality of angled deflectors disposed at an angle of less than about 45-degrees relative to the length of said housing.

5. The finger duct of claim 1 wherein the number of said plurality of angled deflectors, the spacing between said angled deflectors, and the angle of said angled deflectors are optimized to result in a discharge of heated air from the plurality of outlets openings generally evenly along said length of said housing.

6. The finger duct of claim 1 wherein the number of said plurality of angled deflectors, the spacing between said angled deflectors, and the angle of said angled deflectors are optimized so that a pressure and a temperature are generally constant over the surface to be heated.

7. The finger duct of claim 1 wherein said housing longitudinally tapers from said inlet opening to a distal end of the housing.

8. The finger duct of claim 1 further comprising a diffuser disposed between said plurality of outlets and said at least one divider.

9. The finger duct of claim 1 wherein said housing longitudinally tapers from said inlet opening to a distal end of the housing, said at least one elongated divider disposed in and along the length of said housing comprises a plurality of elongated dividers, and said plurality of angled deflectors comprises a plurality of angled deflectors disposed in a staggered checkered pattern in said plurality of longitudinally-extending channels for directing the heated air toward the plurality of outlets in said housing.

10. The finger duct of claim 9 wherein said plurality of angled deflectors is sandwiched between said divider and said housing in the longitudinally-extending channels.

11. The finger duct of claim 9 wherein said plurality of angled deflectors comprises a plurality of angled deflectors disposed at an angle of less than about 45-degrees relative to the length of said housing.

12. The finger duct of claim 9 wherein the number of said plurality of angled deflectors, the spacing between said angled deflectors, and the angle of said angled deflectors are optimized to result in a discharge of heated air from the plurality of outlets openings generally evenly along said length of said housing.

13. The finger duct of claim 9 wherein the number of said plurality of angled deflectors, the spacing between said angled deflectors, and the angle of said angled deflectors are optimized so that a pressure and a temperature are generally constant over the surface to be heated.

14. The finger duct of claim 9 further comprising a diffuser disposed between said plurality of outlets and said at least one divider.

15. An oven for heat treating a product, said oven comprising:

a housing having a front sidewall, a rear sidewall, a right sidewall, a left sidewall, a top, a bottom, and an interior wall extending between said right sidewall and said left sidewall to define a first chamber and a second chamber in said housing;

means for heating air in said first chamber;

an elongated finger duct of claim 1 in fluid communication with said first chamber for receiving heated air from said first chamber and discharging the heated air along a length of said finger duct in a first direction towards a surface to be heated in said second chamber.

16. An oven for heat treating a product, said oven comprising:

a housing having a front sidewall, a rear sidewall, a right sidewall, a left sidewall, a top, a bottom, and an interior wall extending between said right sidewall and said left sidewall to define a first chamber and a second chamber in said housing;

means for heating air in said first chamber;

an elongated finger duct of claim 9 in fluid communication with said first chamber for receiving heated air from said first chamber and discharging the heated air along a length of said finger duct in a first direction towards a surface to be heated in said second chamber.

17. A method for distributing air in a finger duct for use in an oven for heat treating a product, the method comprising:

introducing a flow of heated air into an inlet of the finger duct;

dividing the flow of heated air into a plurality of longitudinally-extending channels in the finger duct;

staggering the deflection of the flow of air in adjacent ones of the plurality of longitudinally-extending channels toward a plurality of outlets in the finger duct; and

discharging the deflected flow of air in each of the plurality of longitudinally-extending channels from respective plurality of outlets in the finger duct.

18. The method of claim 17 wherein the deflecting the flow of air in adjacent ones of the plurality of longitudinally-extending channels comprises deflecting the flow of air in the plurality of longitudinally-extending in a staggered checkered pattern.

19. The method of claim 17 further comprising distributing the discharge of heated air generally evenly from the plurality of outlets.

20. The method of claim 17 further comprising tapering the plurality of longitudinally-extending channels from the inlet opening to a distal end of the housing.

21. The method of claim 17 further comprising diffusing the flow of air out of the plurality of outlets.