The present invention relates to a burner device for cooking food .

Among the various types of gas-powered burners normally used and which can be powered with vaporized liquid fuel, those most widely used for cooking are defined "ramp" burners and "pipe" burners .

Both types of burner can have the area in contact with the flame produced in metal , ceramic or other suitable materials .

Ramp burners are used for both the cooking of food products , such as spit roasting and/or the like, and also for heating plates or other cooking forms .

Pipe burners can be mainly used for plates , in a single or multiple application and for fryers , and therefore also for cooking food products .

In this respect, gas fuel burners are known and used, which have drawbacks specifically due to the type of said fuel .

The use of gas fuel, in fset ^ hcis fr3z3.icls relating to fire of the device and explosion of the whole cooking equipment or quite simply of the tank containing said fuel, such as LPG .

Although this type of burner is only used in open environments , it is always dangerous for the occurrence of fuel loss and possible stagnation present in the air which leads to the risk of explosion, as this fuel is highly flammable .

Alternatives to this solution have consequently been sought .

In an alternative of this type of multiple nozzle burner, the use of a liquid fuel can be provided .

For liquid fuel, moreover, it is provided that, in order to be burnt correctly, it must be brought to the gaseous state . This takes place through heating the same liquid to cause its boiling and subsequent overheating of the steam.

During the passage of the steam to the nozzles of the burner, it is essential that the temperature be maintained at a certain level to avoid its re- condensation and this is not entirely easy in the devices so far used with multiple nozzles, especially if they have a certain longitudinal extension .

US 4 396 372 A describes a multiple nozzle burner of the ramp type associated with a venturi tube and with a series of nozzles.

JP H06 129611 describes a burner device for burning liquid fuel with a gasification chamber and air-heating chamber .

A general obj ective of the present invention is to provide a burner device for cooking food with the use of a liquid fuel with food characteristics .

A further obj ective of the present invention is to provide a burner device which burns correctly to comply with the regulations in force .

Another obj ective of the present invention is to provide a burner device that does have backfiring and in which internal self-ignition is avoided .

Yet another obj ective of the present invention is to provide a burner device that provides a uniform flame and with the same height for the whole of its length, avoiding any problems in the combustion area and with the nozzles .

A further obj ective of the present invention is to provide a burner device that is particularly functional and does not have exorbitant costs .

In view of the above obj ectives , according to the present invention, a burner device for the cooking of food has been conceived, having the characteristics specified in the enclosed claims .

The structural and functional characteristics of the present invention and its advantages with respect to the known art will appear even more evident from the following description, referring to the enclosed illustrative and non-limiting drawings , of a burner device for cooking food produced according to the same invention .

In the drawings :

- figure 1 is a partial schematic view, and partly in a longitudinal section at different levels , showing a burner device with multiple nozzles for cooking food, for example for spit roasting and/or the like, according to the present invention;

- figure 2 is a partial schematic view from above of the burner device of figure 1 , with a partially split part ;

- figure 3 is a transversal sectional view of part of the device of figure 1 ;

- figure 4 is a partial front view of what is shown in figure 3;

- figure 5 is an enlarged partially sectional view showing only the two chambers superimposed according to the line V-V of figure 3;

- figure 6 is a side view of figure 1 also containing the actuation scheme of the shutter and probe relating to a burner device according to the present invention;

- figure 7 is a possible embodiment of an air and fuel system scheme that can be used, for example, in the multiple nozzle burner of the previous figures ;

- figures 8 and 9 are a raised sectional side view and sectional plan view from above of a burner device for cooking food according to the present invention with an independent power supply for each single pipe burner;

- figures 10 and 11 are a raised sectional side view and sectional plan view from above of a burner device for cooking food according to the present invention with a steam-air supply and venturi for each single pipe burner;

- figure 12 is a partially split raised side view of a burner device for cooking food according to the present invention with direct steam-air supply with a single venturi to pipe burners ;

- figure 13 is a side view of figure 8 also containing the shutter actuation scheme .

With reference in general to the figures , these show, in schematic views , a burner device for cooking food according to the present invention .

Figures 1 to 7 show a multiple-nozzle ramp burner device, in particular for cooking food, such as spit roasting and/or the like, according to the present invention, whereas figures 8 to 12 show a pipe burner device in various different applications .

The figures show a general structure 10 in which there is at least one support for a food product to be cooked . In the case of a spit cooking oven, two supports for a spit that rotates inside the structure, are positioned laterally on opposite transversal walls .

In the general structure 10 , the multiple-nozzle burner device according to the invention partly schematized in the longitudinal sectional view of figure 1 and in the subsequent views of figures 2 to 6, is positioned in correspondence with a bottom wall .

This figure 1 shows a pair of tubes 11 and 12 for feeding air in the pre-heating and functioning phase for cooking . In a first functioning phase , in fact , at least one of said tubes 11 and 12 feeds air to a vaporizer 13. On passing inside the vaporizer 13, the air fed is heated by a resistance 14 positioned inside the same .

The heated air leaves the vaporizer 13 through a nozzle 15 and, directed towards a venturi 16, creates an induced suction, and, due to the specific presence of the above-mentioned venturi 16 , sucks in air from a movable wall . Said movablΘ Weill SCtS 3.S cL shutter (figure 6) as it is formed by a plate 17 , having a plurality of holes 18 and is movable with respect to the structure 10 , thanks to slots 19 formed in the plate 17 and that can be moved with respect to pins having an enlarged head 20 integral with the wall of the structure 10.

In this way, a considerable suction of air is created by this arrangement resembling a shutter, but with a double function as illustrated hereunder .

The air sucked from this plurality of holes 18 is sent to be heated to a series of flaps 21 outside the vaporizer 13.

The air thus heated, passing through the venturi 16, is then introduced downstream into a first end of a chamber 22 and forced to reach the opposite end of the chamber 22 in the burner device to be able to then return towards an initial area, passing into a second chamber 23. In the example, the chambers 22 and 23 are arranged consecutively, superimposed and adj acent and connected in correspondence with the terminal area of the first chamber 22 and initial area of the second chamber 23.

The air thus heated, passing through this second chamber n reaches a combustion area consisting of a series of combustion nozzles 24 passing through a third chamber 25 connected to the chamber 23 in succession with appropriate holes 26, shown in figure 5. The third chamber 25 is also adj acent to the second chamber 23. The combustion nozzles 24 are facing upwards , adj acent to each other in succession along the whole length of the burner device .

A heating resistance 27 (figure 2 ) positioned on the rear part of the bottom wall has the specific purpose of accelerating and ensuring that the optimum temperature has been reached in the initial phase .

The same arrangement applies to the normal functioning mode with the only difference that there is only the feeding of supplementary combustion air mixed with liquid fuel introduced into the vaporizer to be transformed into the vapour state .

Feeding means of a liquid fuel towards the evaporator 13 are in fact also provided, which are activated once the first pre-heating phase has been ^f * ^" t j. ·

It can be noted how, in a multiple-nozzle burner device according to the invention, a liquid fuel such as isoparaffin or a similar mixture of vaporized hydrocarbons , with food characteristics , is used as fuel .

As can be seen from the arrangement briefly described above, it is extremely important to pre-heat the whole multiple-nozzle burner device and keep it at the appropriate temperature for subsequently effecting a correct combustion and a regular functioning of the burner device . As already described, in an initial phase, a suitable quantity of compressed air is used for the purpose ( fed by tubes 11 and 12 ) , passed through the vaporizer 13 and subsequently introduced into the venturi 16 through the nozzle of the fuel 15. This is to create an induced suction of a higher quantity of air which, introduced from the plate provided with holes forming a shutter, passing through the outer flaps 21 of the same vaporizer 13, causes the uniform heating of the whole burner device .

As already mentioned, after this initial phase, the normal functioning mode is adopted, in which the feeding of ording to what is illustrated, from the tube 11 is stopped, and the sole feeding of supplementary combustion air is present, mixed with liquid fuel, which is fed in a different way, of which a feeding example is provided hereunder .

Once a certain uniform and pre-established temperature has been reached, a fuel valve is opened and the combustion is started .

Figure 7 shows , through a scheme, a possible embodiment of 3.11 cL 13 and fuel plant that can be associated with the multiple-nozzle burner device of the invention .

Air, coming from a tube 28 , passes through an electrovalve 29, normally closed, and reaches in succession a small tank 30 and subsequently a pressure regulator 31 , then passing from a valve 32 , normally open, and finally reaching the vaporizer 13 and subsequently exiting from the respective nozzle 15.

A further quantity of air also coming from the tube 28 , through another tube 33 , reaches a pressure regulator 34 and, through another tube 35 , passes to an upper part 36 of a tank 37. Contemporaneously, a part of this further quantity of air, passing from a flow- rate regulator 38 , also reaches the above-mentioned vapori zer 13.

The liquid fuel is sucked by means of a pump 40 , from a tube 39 and sent to a lower part 41 of the same tank 37 , causing a float 48 positioned therein, to be raised . Appropriate run-ends 42 and 43 (stopping elements ) cause the stopping and starting of the pump 40 so as to always guarantee the presence of fuel in the tank 37.

Once the pre-heated previously described has been completed, a valve 44 , normally closed and also provided in the plant, is opened .

The fuel, present and pressurized in the tank 37 , passing from a flow-rate regulator 45, reaches the vaporizer 13 and is then immediately vaporized and overheated, subsequently exiting, together with the combustion air, arriving from the flow-rate regulator 38 , from the nozzle 15 and then reaching the combustion nozzles 24.

The pre-heating air coming from the valve 32 and directed towards the vaporizer 13 through the tube 11 , is blocked simultaneously with the opening of the valve 44.

It should be pointed out that in the quenching phase or due to lack of electric power supply, the valve 32 is opened with such a delay as to allow the combustion of the whole quantity of fuel contained after the valve 44.

In a subsequent phase, the air contained in the tank 30 , partly used for completing the combustion, passes into the vaporizer 13, until exhaustion, completely cleaning it, so as to prepare it for a further start-up .

The scheme provided hereunder is naturally only an illustrative, but non-limiting, example, for the functioning of the whole unit .

Upon observing the feeding scheme, it can be noted that, during the pre-heating, the air reaches the vaporizer 13 from both the pre-heating valve 32 itself and also from the flow-rate regulator 38 whereas , during normal functioning, it only arrives from the flow-rate regulating valve 38 through the tube 12. During normal functioning, fuel obviously also enters .

The quantity of air passing through the flow-rate regulator 38 is calibrated so as to obtain a perfect combustion simply with the air sucked from the venturi 17 , as there is air induced by the vapour and air induced by the supplementary air .

re is no need for secondary air, this type of burner can therefore be used in completely closed cooking appliances .

It can be seen how the burner device according to the present invention is composed of a series of chambers (22, 23 and 25) so as to obtain a relatively uniform pre-heating to an equally homogeneous temperature during functioning, and a regular flame height over the whole length of the burner device containing all the nozzles 24.

In this way, according to the invention, a correct burning can be effected so as to respect the regulations currently in force and uniformly cook the products to be cooked .

It should be noted that the particular form of the burner unit, substantially and preferably L-shaped as can be seen in figure 3 , ensures that the flame of the nozzles 24 and the reverberation of heat caused by the provision of a support 46 containing heating plates 47 , contribute to heating the chamber 22 so as to exclude or almost exclude the supplementary resistance 27 , thus reducing electric energy consumption .

In order to maintain temperature control of the chamber 22 inside the same, the burner of the present invention provides the positioning of a probe 49 connected to expandable bellows 50. With a rise in temperature, the bellows 50 , by means of a run amp1ifier 51 , drive a rod 52 , which changes the position of the plate 17 of the shutter causing it to move upwards . This movement causes the partitioning of the air entering from the slits 18 (figure 6) .

Furthermore, from figures 1 and 2 , it can be observed how the plate 17 is folded at an angle of 90° in an upper part 53 and therefore has the form of an overturned L so as to be normally arranged as a cover of an opening 54 formed above the structure 10.

The above-mentioned upward movement therefore also causes the lifting of the upper part 53 which, upon opening the air inlet or upper opening 54 of the structure 10 , allows the entry of non-preheated air so as to stabi1ize the temperature and avoid internal ignition due to an excessive temperature rise . In addition to the above-mentioned function, the movement of the rod 52 which drives the plate 17 of the shutter, also serves to start up the system by commanding through its cams 55 and 56 respective two microswitches 57 and 58 which exert various functions after reaching a pre-established temperature, for example the first 57 driving the valve 44 (or valve 32) and the second 58 spark plugs 61.

It is therefore evident how said rods 52 bear selective actuation means for further elements of the burner device .

To prevent fouling of the nozzles 24 , which are provided with 3. ΠΊΘ13.1 mesh to avoid backfiring, protection screen 59 is positioned along the whole burner, as indicated in figure 4 , so that splashes caused by cooking do not reach the same nozzles 24.

The screen 59, folded so as to adequately cover the nozzles 24 , is supported by two brackets 60 , also indicated in figure 4 , and is therefore free to move and expand to avoid deformation .

An advantageous consequence of this is the prevention of any possible depositing of dirt on the nozzles 24.

The burner system is obviously provided with all apparatuses and devices required by the standards in force, for guaranteeing functioning in complete safety .

The uniform temperature distributed along the whole longitudinal dimension of the burner device produces and allows a uniform flame over the whole length and therefore ensures regular cooking .

An advantageous start-up of the device is therefore achieved, which also allows a subsequent temperature control of the same burner . Furthermore, extremely limited electric power supplies are used .

The previous figures show a type of ramp burner which can alternatively be substituted by a so-called "pipe" burner .

Figures 8 to 12 show some application examples of this type of pipe burner . In these examples , when possible, the same reference numbers as in the previous example are used for the same elements .

Figures 8 and 9 are a raised sectional side view and sectional plan view from above of a burner device for cooking food according to the present invention with an independent power supply for each single pipe burner .

Figure 8 , in fact, shows how a single vaporizer 13 can be followed by a respective pipe burner that provides a steam-air nozzle 15 associated with a venturi 16. The venturi 16 is in turn connected to a pipe burner body 70, provided with nozzles, not shown, provided at the end with a chamber 22 of a thermal- exchange tube 73. Each pipe burner body 70 is connected to a respective vaporizer 13 and, structured as previously described for figures 1 to 6, forms an air- passage tube towards a thermal-exchange area immersed in food cooking oil 71 contained in a tank 72.

For self-heating burners during normal functioning, figure 13 shows a further possible command of the plate 17 of the shutter .

A supporting stand 76 is in fact provided above the structure 10 of the vaporizer 13, which carries a linear actuator 77 , such as , for example a cylinder . The plate 17 of the shutter as positioned in figure 13 is in a pre-heating position with an energized actuator and in the normal functioning position when the actuator is de-energized.

In this further example, the electrovalve 32 normally open in figure 7 , in this additional command of the plate 17 , is substituted by an electrovalve 32 normally closed .

If, for example, a spit is being activated, the electrovalve 32 in this case normally open, is energized, as are also the actuator 77 and the heating resistances 14 and 27. Once the temperature previously set, controlled by a probe 49, has been reached in the chamber 22 of the burner, the electrovalve 32 , the actuator 77 and the supplementary heating resistance 27 are simultaneously de-energized and the ignition of the burner started .

Figures 10 and 11 are a raised sectional side view and sectional plan view from above of a burner device for cooking food according to the present invention with a partial steam-air supply and venturi for each single pipe burner

A single vaporizer 13 feeds a single steam-air tube 74 towards a series of nozzles 15 for a steam-air associated venturi 16. The venturi 16 is in turn connected to a pipe burner body 70 , provided with nozzles (not shown) , provided at the end with a chamber 22 of a thermal exchange tube 73. Each pipe burner body 70 is connected to a single air passage duct 75 connected to the single vaporizer 13 which is structured as previously described for figures 1 to 6.

The air passage duct 75 is connected to a thermal exchange area immersed in food cooking oil 71 situated in a tank 72.

Finally, figure 12 is a partially split raised side view of a burner device for cooking food according to the present invention with direct steam-air supply coming from the vapori zer 13 with a single venturi 16 to pipe burners 70.

These examples also show burner devices according to the present invention .

The obj ective mentioned in the preamble of the description has therefore been achieved .

The forms of the structure for providing a burner device for cooking food of the invention, as also the materials and assembly modes , can naturally differ from those shown for purely illustrative and non-limiting purposes in the drawings .

The protection scope of the invention is therefore defined by the enclosed claims .