FR2738900A1 - FORCED VENTILATION COOKING OVEN - Google Patents

Abstract

This oven comprises a cooking chamber (1), a fume carrier (5) and a heating chamber (2) communicating. The heating chamber is traversed and heated by the ambient air sucked in by blowing means arranged in a ventilation chamber (7), while the fume carrier is directly touched by the flow of gas blown outside the chamber. ventilation chamber, the hot gases being cooled, before reaching the cooking chamber. An exhaust duct (6) of the exhaust burnt gases and vapors produced in the cooking chamber, and a hot gas exhaust path (4), are completely separate. The suction chamber ends in an annular shape, one side of which is at least partially open towards the interior of the ventilation chamber.

Description

FORCED VENTILATION COOKING OVEN

  The present invention relates to a ventilated oven for cooking food, suitable for carrying out cooking by means of a flow of burnt gases which, produced by a plurality of heating elements, is forced by one or more fans to circulate in a heating chamber, in which is arranged

  the food to be cooked or reheated.

  More particularly, the invention relates to a convection oven with direct heating, that is to say of the type in which there is a direct introduction of

  burnt gases in the heating chamber.

  During the description, we will refer to

  peculiar to an oven for cooking food for community but, according to what is described and

  claimed, it is obvious that this description

  applies to any type of oven for cooking food, which is why it is provided with means for agitating the atmosphere internal to the cooking chamber. It is known that cooking in a food oven involves particularly different methods depending on the results and effects which it is desired to obtain, but that there are also specific drawbacks, such as overheating of the supply conduits. burnt gases and poor accessibility to the various components, in particular to the heating elements which can be produced

with burners.

  Normally, in fact, in such ovens, the burnt gases reach very high temperatures, of the order of 700 to 900 ° C., for which it is necessary, to limit the heating, to use special materials and therefore expensive, having special characteristics of resistance to thermal stresses, or of having recourse to processes which make construction and use

even more complicated.

  In addition, in some cases, the combustion chamber and the burners are housed near the bottom of the oven itself, which is why the other components of the oven (such as the blower motor and the controls) are of course also subjected to high and unwanted temperatures which

  decrease operational reliability.

  In particular, by patent GB 1 507 371, from the same applicant, there is known an oven for cooking food, provided with a combustion chamber arranged exactly behind the oven itself, and with a device for diluting the fumes. operating by means of a mixture between the hot gases from the combustion and the colder gases present in the cooking chamber. This solution has the disadvantage that the dilution exhaust gases, transporting impurities and fatty particles, contaminate the suction duct in which they are located, as well as the combustion chamber in correspondence with the reversing edges. of the flow. Contact of the above substances with hot gases at high temperature causes chemical cracking with production of black smoke and unwanted volatile compounds which, being emitted in the cooking chamber, affect the quality and presence

food being present there.

  In addition, in the mentioned patent is provided a single path through which are evacuated: - combustion gases (during the transitional period of the rotor start or a propeller failure) - combustion gases, plus steam , produced by cooking the food (once the speed is reached) The volume of the aforementioned gases varies according to the temperature of the oven and the amount of water evaporated by the food, producing variations in the volume flow rates of evacuation very sensitive, this is detrimental to the efficiency of the cooking process, since they alter the normal combustion gas suction conditions, with loss of thermal efficiency. In addition, the position of the combustion chamber, exactly at the rear of the oven, makes it particularly complicated to use, as long as the burner flame is not directly visible by an operator normally placed in front of the oven (and we know how important it is, for safety, to be able to immediately and directly verify the presence or not of a regular flame), only because the longitudinal dimensions of the oven, already penalized by the arrangement of the propeller on the vertical bottom of the cooking chamber, also increases by

  detrimental way the very ease of installation of the oven.

  It is therefore necessary to have a ventilated oven, in particular for supplying communities, which overcomes the drawbacks described and whose construction is simple, reliable and which

  uses available technologies.

  The object of the present invention is to provide an oven of the type mentioned with forced convection, the components of which, in particular the heating elements,

are easily accessible.

  Another object of the invention is to provide an oven which does not have an increase in its

longitudinal dimensions.

  Another object of the invention is to provide an oven of the type mentioned, having an improved system of circulation of air between the combustion chamber, the heating chamber and the exhaust, so as to ensure an optimal technical state of operation,

  while avoiding the use of special materials.

  The object of the present invention is to describe this cooking oven having the characteristics essentially described and in particular: a forced convection oven, in particular for cooking food, comprising a cooking chamber, a smoke conveyor and a heating chamber provided with suitable heating means which communicate substantially with one another in a known manner, said heating chamber being traversed and heated by ambient air sucked in by blowing means arranged in a ventilation chamber, these blowing means being adapted to circulate in a substantially closed circuit, composed of said cooking chamber, said smoke conveyor and said ventilation chamber, a gas flow in heat exchange relationship with said heating chamber, which is provided with a path for evacuating burnt gases, a possible plurality of dishes being arranged vertically in said cooking chamber, ca characterized by the fact that said smoke conveyor is substantially disposed in said ventilation chamber and is directly touched, at least on the two horizontal surfaces, by the flow of gas

  circulating in said ventilation chamber.

  The invention will be better understood on reading

  the description which follows, given by way of example only

  non-limiting and with reference to the appended drawings, in which: FIGS. 1, 2 and 3 represent respectively, in front section (A- A), side (BB) and in top plan, an oven according to the invention, with a single combustion chamber and a single fan, Figures 4 and 5 respectively show a front and side section of an oven with a single combustion chamber, but two superimposed fans, according to invention, FIG. 6 represents a front view of an oven provided with two fans and two burners

superimposed according to the invention.

  For the sake of convenience, in the description which

  below, reference is made to the heating means contained in the heating chamber as a typical gas burner in the ambient atmosphere, but it is obvious that other types of heating device can advantageously be used. Referring to Figures 1, 2 and 3, there is shown a cooking oven for community food, forced circulation, comprising a cooking chamber 1, a heating chamber 2 provided with heating means 3, preferably burners gas, a path 4 for evacuating combustion gases, a smoke conveyor 5 for combustion gases, an evacuation duct 6 for escaped combustion gases and

  vapors produced in the cooking chamber.

  The oven further has a ventilation chamber 7 which houses a motorized fan, of the conventional type and not numbered in the figure, and disposed towards the rear of the oven. As illustrated in FIG. 2, the suction wall 10 is profiled in its front part so as to end in an annular gap 8, open on the edge 9 facing towards the central part of the ventilation chamber and having dimensions and positions such that the gas flow at the outlet of the annular gap 8 has a consecutively annular shape and moves towards

  inside the ventilation chamber.

  As a result, the suction of the combustion gases is carried out along the entire annular suction section of the fan, thus improving both the suction and the discharge in suitable conduits, not shown and known in the art, suitable for distribute the gas inside

from the cooking chamber.

  The advantage of such a configuration results from the fact that the smoke conveyor 5 is completely exposed to the flow produced by the propeller and therefore serves as a heat exchanger between the "cold" gases (up to around 300 ° C.). circulation in the ventilation chamber, and the hot combustion gases coming from the combustion chamber, which cool and reach the suction gap 8 at a

  temperature preventing any overheating of the sheets.

  This mode of operation overcomes the drawbacks resulting from the dilution of hot combustion gases with "cold" exhaust gases, which are encountered in an oven according to the aforementioned patent; in fact, in the present invention, because of not mixing "dirty and cold" gases with "clean and hot" gases, the cited drawbacks cannot be encountered, given that the hot gases produced by the chamber are significantly cooled in the smoke conveyor, serving as a "heat exchanger" before they are mixed with the dirty gases present in the

cooking chamber.

  In addition, with the construction configuration shown in the figures, it is possible and advantageous to have the heating chamber 2, not at the rear but at the front of the oven, with obvious advantages both in terms of space requirement of the furnace, that of its operational safety, given that, in this way, it is possible to observe directly, from a location located at the front of the furnace, the presence or absence of the flame 3 of the burners or

  activation of the heating means.

  The illustrated solution also has a suitable conduit 6 for evacuating the escaped combustion gases and the vapors produced in the cooking chamber. We find the advantage of this solution by making the operation of the two paths independent, so that, faced with temporary or irregular operating situations in one of the conduits, this only minimally influences the

  operating conditions of the other duct.

  The suction wall 10, constituted by a substantially vertical plane wall, separates the

  ventilation of the cooking chamber.

  Preferably, the planar wall 10 is disposed adjacent to the front edges of the ventilation chamber and of the smoke conveyor 8, and is open in correspondence with the suction mouth of the

ventilation chamber.

  Advantageously, the smoke conveyor 8 can be profiled in a substantially reduced form 11 from the inlet mouth 11 of the gases coming from the heating chamber, in the direction opposite to said mouth; the advantage of this solution results in the fact that the gradual reduction in the flow rate of the heated and aspirated gas flow requires a corresponding reduction in the dimensions of the conduits, under penalty of causing an imbalance of pressures and an irregular suction of gases; in addition, this allows more efficient movement over the conveyor

  even, in order to cool it better.

  Of course, taking into account the fundamental teachings described in the present invention, it is possible to produce ovens having a greater number of suction walls 13, 14, and a single smoke conveyor 15, with corresponding heating chambers, such as represented in FIGS. 4 and 5, and also, in correspondence with a single cooking chamber, there can be a plurality of heating chambers 16, 17, respective smoke transporters 19, 20 and ventilation chambers 21, 22 respective. It should be noted that, according to the invention, the advantages can be obtained in convection ovens having the vertical dimensions

  most different internal, according to requirements.

  This allows the performances of the oven to be substantially identical, regardless of its capacity and

  the number of dishes provided in the latter.

  In addition, it should be noted that the convection oven according to the invention can have an advantageously reduced depth compared to conventional solutions. This is due to the fact that the motors which actuate the fans can be housed, without the need for suitable means of transmission, outside the upper wall of the housing which contains the fans, that is to say in an area which does not have normally no congestion problem. The oven is, of course, equipped with many other devices which, not being part of this patent,

are omitted.

  Although the invention has been described according to the preferred embodiment and with generally known terminology, it is not limited

  by this description, those skilled in the art can

  make many variations and modifications of

construction and form.

Claims (10)

  1. Forced convection oven, in particular for cooking food, comprising a cooking chamber (1), a smoke conveyor (5) and a heating chamber (2) provided with suitable heating means (3) which communicate substantially with each other in a known manner, said heating chamber being traversed and heated by ambient air drawn in by blower means arranged in a ventilation chamber (7), these blower means being adapted to circulate in a substantially closed circuit , composed of said cooking chamber, said smoke conveyor and said ventilation chamber, a gas flow in heat exchange relationship with said heating chamber, which is provided with a path (4) for evacuating gases burnt, a possible plurality of dishes being arranged vertically in said cooking chamber, characterized in that said smoke conveyor (5) is substantially arranged in said chamber ventilation (7) and is directly touched, at least on the two horizontal surfaces, by the flow   gas circulating in said ventilation chamber.   2. Ventilated oven according to claim 1, characterized in that it comprises a discharge duct (6) for the burnt exhaust gases and the vapors produced in said cooking chamber, and in that said path (4) d hot gas discharge and said exhaust gas exhaust and vapor exhaust duct are two ducts   completely distinct and without common path.   3. Ventilated oven according to claim 2, characterized in that said smoke conveyor (5) ends in the direction of flow of the gas which runs through it, with an annular gap (8) including one l1 side (9), opposite at the position of said cooking chamber, is at least partially open towards the inside of said ventilation chamber, so that the gas which flows through said suction chamber is sent in an geometry at least partially annular against the edges d 'Entrance said blowing means.   4. ventilated oven according to claim 1 or 2 or 3, characterized in that said ventilation chamber (7) is arranged on the vertical bottom wall of said ventilated oven, that said smoke conveyor is disposed substantially above said ventilation chamber and that deflector means are provided which separate, on one side, said cooking chamber, and on the other side, said smoke conveyor and said ventilation chamber, said separation means being open facing the opening   suction of said ventilation chamber.   5. ventilated oven according to claim 4, characterized in that said deflector means comprise a planar wall (10) substantially vertical and that said wall is disposed substantially adjacent to the front edges of said   ventilation chamber and said smoke conveyor.   6. Ventilated oven according to any one of   previous claims, characterized in that   said heating chamber is disposed laterally to said smoke conveyor, with respect to a view of   face of said suction chamber.   7. Ventilated oven according to any one of   previous claims, characterized in that   said smoke conveyor is profiled in a substantially reduced form (11) from the gas inlet mouth coming from said combustion chamber   heating, in the direction opposite to said mouth.   8. Ventilated oven according to any one of   previous claims, characterized in that   said heating means comprise at least one gas burner disposed in place at a lower position relative to the mouth, which establishes a communication between said heating chamber and said smoke carrier.   9. Ventilated oven according to any one of   previous claims, characterized in that   the ventilation chambers are two in number (13, 14) and superimposed, that the smoke conveyor (15) is arranged in the intermediate space between said two ventilation chambers, and that said smoke conveyor ends in the direction of the gas flow which flows through it, through two distinct annular interstices (25, 26), a respective side of which, opposite the position of said cooking chamber, is at least partially open towards the interior of the corresponding ventilation chamber, so that the gas which flows through said annular interstices is sent in an at least partially annular shape against the inlet edges of said respective ventilation chambers. 10. Ventilated oven according to any one of   Claims 1 to 8, characterized in that, facing   a single cooking chamber is provided with a plurality of heating chambers (16, 17), respective smoke transporters (19, 20), and   respective ventilation chambers (21, 22).