Stoves and furnaces – Stoves – Cooking
Reexamination Certificate
1999-05-28
2001-02-27
Lazarus, Ira S. (Department: 3743)
Stoves and furnaces
Stoves
Cooking
C126S01500R, C126S022000, C099S447000, C034S225000, C432S145000
Reexamination Certificate
active
06192877
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improved blown air distributor suitable for use with a convection oven that cooks food by impingement.
BACKGROUND OF THE INVENTION
Impingement food ovens are mostly used in fast food restaurants for rapidly cooking food such as pizza, pre-cooked meals, sea food souffle, cookies, etc. by air streams which impinge against the surface of the food products. Example of prior art impingement food oven are described by way of example in U.S. Pat. No. 5,584,237 in the name of the applicant; U.S. Pat. Nos. 5,584,237; 5,423,248; 4,965,435; 4,462,383; and 4,753,215.
There is also the reference EP-0286759, which discloses a convection oven comprising a plurality of finger ducts mounted in parallel in the baking chamber of the oven. Each of the finger ducts has an air inlet to receive heated air from a plenum and a plurality of air outlets to dispense the heating air in the baking chamber.
Most of prior art impingement food oven comprises finger ducts mounted in the cabinet of the oven above and below a conveyor to form streams of forced heated air which are directed towards the product on a conveyor. In general, the finger ducts rapidly become dirty or fouled up and must be regularly cleaned up. In prior art, the finger ducts are independent from each other so that they are mounted or dismounted one by one by sliding each one of those in guide rails adapted to receive a corresponding finger duct. As can be easily understood, the cleaning up of all the finger ducts is time-consuming and very expensive because each of those finger ducts has to be removed, cleaned up and put back in the oven, one after another. Moreover, often, the finger ducts are not put back in their proper place, causing an improper cooking of the products. There is thus presently a need for an impingement convection oven provided with finger ducts that may be rapidly and easily dismounted from the oven or installed therein.
Another drawback often encountered with the elongated finger ducts of prior art impingement food ovens is that the heated air leaving the plenum and forced in each finger duct is moved directly to the opposite end of the finger duct due to its high velocity and causes the food to be cooked uneven. Attempts to resolve this problem by using deflectors mounted inside the finger duct in order to apportion the incoming air flow therein have been proposed in U.S. Pat. Nos. 4,462,383 and 5,423,248. However the design of the deflectors proposed in those prior art documents have not shown satisfactory results and often does not provide a uniform cooking between the product on the front portion of the conveyor and the one in the back portion. There is thus also a need for an impingement convection oven that will consistently show a uniform cooking throughout the oven.
OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention to provide a blown air distributor suitable for use with a convection oven that satisfies the above-mentioned need of having finger ducts that may be rapidly and easily dismounted from the oven or installed therein.
Another object of the invention is to provide a blown air distributor for a convection oven that shows a very good distribution of heated air throughout the baking chamber.
A further object of the invention is to provide a convection oven which is very economic in term of the energy required for its operating.
SUMMARY OF THE INVENTION
The blown air distributor according to the present invention is suitable for use with a convection ovens of the type comprising a baking chamber and a convection system including a blower to draw air from the baking chamber, a source of heat to heat the air drawn from the baking chamber and a plenum in open communication and downstream from the blower to recirculate heated air into the baking chamber, the blown air distributor comprising:
a plurality of finger ducts mounted in parallel in the baking chamber, each finger duct having an air inlet to receive the heated air from the plenum and a plurality of air outlets to dispense the heated air in the baking chamber:
the blown air distributor being characterized in that:
the finger ducts are mounted on a single plate removable from the baking chamber; and
the single plate has opposite side edges each slidably receivable in a guide way provided on a corresponding side wall of the baking chamber, the single plate being also provided with a plurality of air inlets to receive the air from the baking and drawn by the blower, thereby providing a communication between the baking chamber and the blower.
A convection oven may advantageously be provided with only one blown air distributor according to the present invention or preferably two, one for installation over the food to be cooked and the other one for installation under the food.
According to a preferred embodiment of the present invention, the blown air distributor is characterized in that it comprises 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 side wall 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 provided. This 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.
Another object of the present invention is also to propose a combination of a blown distributor with a convection oven as described hereinbefore.
According to a preferred embodiment of such combination the convection oven is characterized in that it comprises an aerodynamically-shaped duct defining the plenum of the oven. The aerodynamically-shaped duct has an inlet in open communication with the blower and an outlet in open communication with the inlet of each of the finger duct.
As can be appreciated, the blown air distributor according to the present invention, thanks to the fact that all the finger ducts are mounted on a single plate slidable into the baking chamber, is very easy and rapid to install without mixing up the respective emplacement of each finger ducts in the baking chamber. It is also very simple to dismount for cleaning up. According to a preferred embodiment of the invention comprising an adjustable deflector within the finger ducts, the blown air distributor allows a user to easily and rapidly adjust the degree of cooking required in the baking chamber. The deflector may be adjust to obtain a uniform cooking throughout the baking chamber or there may also be adjust to obtain different degrees of cooking.
A non-restrictive description of a preferred embodiment will now be given with reference to the appended drawings.
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patent: 0094816 (1983-05-01), None
patent: 0286759 (1987-12-01), None
patent: WO9641499 (1996-12-01), None
Moshonas Georges
Silva Waldo
Vatista Georges
Cocks Josiah C.
Lazarus Ira S.
McDermott & Will & Emery
Zesto Food Equipment Manufacturing Inc.
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