Stoves and furnaces – Stoves – Cooking
Reexamination Certificate
2002-01-15
2003-04-01
Yeung, James C. (Department: 3743)
Stoves and furnaces
Stoves
Cooking
C126S02100R, C099S44300R, C034S216000, C432S145000, C432S152000
Reexamination Certificate
active
06539934
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates in general to the field of convection ovens that cook food by impingement. More particularly, it concerns a multiconveyor convection oven with an improved heating chamber.
BACKGROUND OF THE INVENTION
Impingement food ovens are mostly used in fast food restauration for rapidly cooking food such as pizzas, pre-cooked meals, sea food souffles, cookies cooking etc., by air streams which impinge against the surface of the food products. Most of such ovens presently in use comprise an air distribution system including one or more air distribution channels located in a baking chamber and one or more blowers for drawing air from the baking chamber and recycling the air at different locations within the same via the air distribution chambers. These ovens also comprise a single conveyor mounted in the baking chamber for carrying food products into, through and out of the cabinet.
Examples of prior art impingement food ovens of this type are described by way of example in U.S. Pat. Nos. 5,584,237 in the name of the applicant; 5,423,248; 4,965,435; 4,462,383; 4,753,215; and 6,192,877.
For the last recent years, a need has developed for more productive multiconveyor impingement ovens. Already known in the prior art, there is U.S. Pat. No. 5,832,812 in the name of Wolfe which discloses a low profile dual conveyor oven including an oven cabinet with two closely spaced conveyors and an air heating and circulation system designed so that the oven has a limited vertical dimension.
SUMMARY OF THE INVENTION
An object of the present invention is to propose an improved impingement oven with more than one conveyor.
According to the present invention, that object is achieved with a multiconveyor convection oven, comprising:
a baking chamber
at least two spaced-apart conveyors mounted transversally one over the other in the baking chamber;
a heating chamber behind the baking chamber, the heating chamber comprising an air heater to heat air circulating in the heating chamber;
a convection system for providing a circulation of the air from the baking chamber to the heating chamber and back to the baking chamber to cook the food, the convection system comprising:
at least one air return passage having an air inlet in fluid communication with the baking chamber and an air outlet in fluid communication with the heating chamber;
a blower housing extending vertically outside the heating chamber on a side thereof;
at least two centrifugal blower chambers, one for each conveyor, mounted one over the other within the blower housing, each centrifugal blower chamber having:
an air inlet in fluid communication with the heating chamber for drawing air from the baking chamber via the at least one air return chamber and the heating chamber and
an air outlet for throwing back heated air at high pressure;
at least two plenum chambers, one downstream from each centrifugal blower chamber, disposed one over the other in between the baking chamber and the heating chamber, each plenum chamber having:
an air inlet in fluid communication with the air outlet of a corresponding one of the centrifugal blower chambers for receiving the heated air at high pressure ; and
at least one air outlet for throwing back the heated air;
ducting means disposed within the baking chamber for conveying the heated air at high pressure exiting from the at least one outlet of the plenum and dispensing the same in the baking chamber to cook food.
Preferably, the multiconveyor convection oven comprises two spaced-apart conveyors mounted transversally one over the other in the baking chamber.
As can be appreciated, the use of a blower housing extending vertically on a side of the oven rather than a blower housing extending horizontally behind the baking chamber as disclosed in U.S. Pat. No. 5,832,812, presents many advantages. Among other things, it makes it possible to build relatively easily a multiconveyor oven with more that two conveyors mounted one over the other. It also allows to free the space of the heating chamber thereby allowing, in a preferred embodiment of the invention, the installation of an efficient system for controlling the distribution of the heat within the baking chamber.
According to another aspect, the present invention also provides a multiconveyor convection oven, comprising:
a baking chamber;
two spaced-apart conveyors mounted transversally one over the other in the baking chamber;
a heating chamber behind the baking chamber, the heating chamber comprising a burner disposed in a bottom portion of the heating chamber and capable of releasing a gas jet to heat air circulating in the heating chamber;
a convection system for providing a circulation of the air from the baking chamber to the heating chamber and back to the baking chamber to cook the food, the convection system comprising:
at least one air return passage having an air inlet in fluid communication with the baking chamber and an air outlet in fluid communication with the heating chamber;
two blower housings extending vertically outside the heating chamber, one extending on a first side of the oven and the other one extending on a second side of the oven opposite the first side;
two centrifugal blower chambers mounted one over the other within each of said two blower housings, each centrifugal blower chamber having:
an air inlet in fluid communication with the heating chamber for drawing air from the baking chamber via the at least one air return chamber and the heating chamber; and
an air outlet for throwing back heated air at high pressure;
a first set of two plenum chambers, one plenum chamber being downstream from each centrifugal blower chamber mounted in one of the two blower housings, the two plenum chambers being disposed one over the other in between the baking chamber and the heating chamber;
a second set of two plenum chambers, one plenum chamber being downstream from each centrifugal blower chamber mounted in the other one of the two blower housings, the two plenum chambers being disposed one over the other in between the baking chamber and the heating chamber;
each of the plenum chambers of the first and second set having:
an air inlet in open communication with the air outlet of a corresponding one of the centrifugal blower chambers for receiving the heated air at high pressure; and
air outlets for throwing back the heated air;
a set of parallel finger ducts disposed over and below each of the two conveyors, each finger duct having an air inlet connectable to a corresponding one of the air outlets of the plenum chambers to receive the heated air therefrom and a plurality of air outlets to dispense the heated air in the baking chamber; and
control means for controlling the distribution of the heated air dispensed in the baking chamber, the control means comprising:
a substantially transversal deflector mounted transversally within the heating chamber above the burner for controlling the distribution of the heat within the heating chamber between the bottom portion and the top portion of the heating chamber, the transversal deflector comprising:
an upwardly curved middle section; and
at least one planar section connectable to each end of the middle section to transversally expand the deflector; and
a substantially vertical deflector mounted vertically within the heating chamber and facing the burner, and capable of controlling the distribution of the heat within the heating chamber between the first side and the second side thereof.
REFERENCES:
patent: 4462383 (1984-07-01), Henke et al.
patent: 4753215 (1988-06-01), Kaminski et al.
patent: 4884552 (1989-12-01), Wells et al.
patent: 4965435 (1990-10-01), Smith et al.
patent: 5277105 (1994-01-01), Bruno
patent: 5423248 (1995-06-01), Smith et al.
patent: 5584237 (1996-12-01), Moshonas
patent: 5832812 (1998-11-01), Wolfe et al.
patent: 6192877 (2001-02-01), Moshonas et al.
Czajka Chuck
Moshonas Georges
Yeung James C.
Zesto Food Equipment Manufacturing Inc.
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