Patent Publication Number: US-2017354155-A1

Title: Automated oven for cooking of bakery products and in particular pizza

Description:
The present invention refers to an automated oven for producing and cooking bakery products, such as pizzas and the like. 
     Currently, bakery products, and in particular pizzas are prepared by specialised workers such as a pizza chef and cooked in an electric, gas, wood or combination oven. 
     Usually, it is recognised that wood ovens offer better performance for cooking pizzas particularly in terms of quality of the result obtained and flavour. However, they have a series of drawbacks. For example, great quantities of wood are consumed and therefore it is necessary to have a store. Furthermore, in order to be used, it is necessary to turn on the oven in advance so that it is at the right temperature at the moment of cooking. The cooking times are also long and this increases the waiting time for customers. 
     It is necessary for the worker to continuously check the oven flame and, moreover, the worker must also take care of cleaning the oven and of disposing of the ashes. Moreover, staying close to the oven for long time periods causes certain discomfort to the worker given that he/she is subjected to the radiation that is emitted at the mouth of the oven. Furthermore, the pizza is manipulated by the worker through a tool called a paddle that is not easy to manipulate due to its length. 
     Moreover, the wood-cooked pizza could be considered less healthy given that it can come into contact with coals, smoke and other combustion products (like for example food residues left on the cooking surface that are difficult to eliminate and produce substances that are toxic to health, such as benzopyrenes or benzofluoranthenes). 
     Finally, the wood oven has a substantial problem due to the different way of absorbing and re-emitting the heat between cooking surface and vault. In particular, the heat of the flame tends, by radiation, to heat the vault more than the portion of the cooking surface on which the pizza rests (shielded from the effect of the radiation of the product itself). This implies that the lower part of the pizza needs longer cooking times than the upper part and that the cooking surface cools down. Moreover, the pizza topping (and the dough itself) contain a substantial percentage of water that during cooking evaporates contributing to subtracting heat from the vault. The excess air that enters from the mouth of the oven, kept open to allow the worker to check the cooking of the pizzas and the entry of air (to feed the combustion) even during cooking, also contributes to lowering the temperature of the flame and of the vault. 
     The object of the oven according to the present invention is to solve the problems described above. In particular, the object of the present invention is to provide an oven that has reduced energy consumption and that does not need specialised workers. Furthermore, the oven according to the invention aims to have optimised and controlled heating in every part thereof. 
     Another aim is to obtain an oven that is hygienic so that the products cooked in it do not come into contact with polycyclic aromatic hydrocarbons (PAHs) like benzopyrenes or benzofluoranthenes considered by the European Food Safety Authority to increase the risk of tumours. 
     The object of the oven is also to reduce the preparation times of bakery products with respect to conventional wood ovens. Finally, the oven according to the invention aims to minimise the production of residues like ashes and fumes. 
     These and other objects are accomplished by the oven according to the invention, the essential characteristics of which are defined by the first of the attached claims. 
     Further important characteristics are defined by the dependent claims. 
    
    
     
       The characteristics and advantages of the oven according to the present invention will become clearer from the following description of embodiments thereof, given as a non-limiting example with reference to the attached drawings, in which: 
         FIG. 1  shows a cross section of an oven according to the invention, with which automated preparation means of a pizza are associated; 
         FIG. 2  shows the oven of the previous figure, with a base for a cooking surface of the pizza moved into a rest position, or starting position; 
         FIG. 3  is an enlargement of the oven of  FIG. 2  with the base still in rest position; 
         FIG. 4 , on the other hand, shows the base in an intermediate position for the preparation of the base; 
         FIG. 5  shows means for the supplying of sauce, in isolation. 
     
    
    
     With reference to such figures and in particular to  FIG. 1 , the oven comprises a cooking chamber  1  and a combustion chamber  2 . The cooking chamber and the combustion chamber are mutually juxtaposed and separated by a semi-transparent wall defined specifically by ceramic glass  3 , suitable for withstanding high temperatures. The oven also has a burner  4  housed in a chamber  40  positioned beneath the combustion chamber and beside the cooking chamber in withdrawn position with respect to it. The burner  4  can advantageously be of the known pellet type, thus not described in detail; the chamber  40  is delimited by refractory walls  41 . In the figures it is also possible to see an Archimedean screw  43  for feeding the pellets to the burner and the ventilation system  44 . 
     The oven structure described is supported by a suitable foundation, able to be deduced in an obvious manner by those skilled in the art and therefore not described in detail, shown only schematically in the figures. 
     Going into even greater detail, the cooking chamber is delimited at the bottom by a cooking surface  10  arranged parallel to and opposite the glass  3 . The cooking surface is made of metallic material, or of lavastone or firebrick with surfaces treated so as to eliminate or reduce porosity as much as possible. It is also thermostated autonomously through heating means (not shown) that will be discussed in detail hereinafter. The cooking chamber also has a mouth  11  for the insertion of the products to be cooked; a bottom wall of the cooking chamber, opposite the mouth  11 , is defined by the wall  41  that delimits the chamber  40 . At the top the cooking chamber  1  is delimited by the ceramic glass  3 . 
     The combustion chamber  2  is delimited at the bottom by the ceramic glass  3  and by an opening  42  that leads directly to the chamber  40  of the burner  4  to allow the flame generated by the combustion that occurs in the burner to develop in the combustion chamber; in the latter combustion fumes also develop. At the top and laterally, the combustion chamber is delimited by a vaulted dome  20  that is of constant height above the ceramic glass, and of progressively lower height above the opening  42 . At the opposite end with respect to the burner  4 , the combustion chamber has a mouth  21  intercepted by valve means to adjust the amount of fumes coming out from the funnel, like for example a butterfly valve  22 . 
     The oven is completely automated since it is managed by electronic means of control and interface, such as a PLC (not shown); in particular, the electronic control means control at least the operation of the burner  4  and of the valve means. 
     For this purpose, the PLC is connected to sensors  5  (shown schematically in  FIG. 2 ) that detect the radiance value in the cooking chamber  1 . The sensors are of the optical type, such as to receive in the infrared spectrum and in the visible spectrum, and are pointed in the direction of the flame in a position such as not to receive electromagnetic radiation from external sources. Such radiation is determined by the vault  20  of the combustion chamber  2 , as well as by the flame and by the ceramic glass itself that, absorbing part of the infrared, retransmits it in the cooking chamber. Therefore, by increasing the temperature of the flame, the heat transmission effect by radiation increases according to the physical law of Stefan Boltzman. 
     In detail, it is possible to determine the increase in temperature of the flame and vault. Concerning this, the refractory glass  3  prevents the entry of steam produced by the pizza cooking in the combustion chamber (steam that would contribute to decreasing the temperature in the combustion chamber); the glass, by heating up and emitting in the infrared, also acts as a combustion catalysing surface; at the same time, the air in the combustion chamber is introduced in a controlled manner, being dosed and mixed with the fuel, indeed, there is not uncontrolled entry of air like in conventional ovens. 
     With reference to such a structure, the operation of the oven is as follows. 
     The burner  4  controlled by the PLC, determines the intensity of the flame in order to obtain a determined radiance value inside the cooking chamber and at the same time also regulates the temperature of the cooking surface  10 ; consequently, by managing the intensity of the flame, the PLC also determines the amount of gas produced. 
     Once the oven is started, the PLC receives the analogue value of the radiation sensors  5  in input and therefore consequently determines the opening of the butterfly valve  22  regulating the flow of flame. In particular, the PLC receives, from the radiation sensors  5 , an analogue value based on which it sets an intensity of fire that licks the vault and make the butterfly valve open, so as to regulate the time for which the gases remain in the combustion chamber. As soon as the oven is switched on, the radiation by the vault  22  is zero. As the temperature of the vault  20  increases, the level of radiation increases and therefore the reduction in intensity of the fire and also the lesser opening of the butterfly valve  22  is controlled. 
     By managing the operating parameters of the oven thanks to the PLC it is also possible to determine the cooking times of the product. In particular, as the radiation increases, the cooking time itself decreases. 
     As illustrated in  FIGS. 2 to 5 , the oven according to the invention can also be associated with means for the automatic preparation of the pizza. Such means comprise a sliding base  6  that foresees a metallic upper surface  60 . The latter can also be made from lavastone or firebrick. Such a base is capable of moving from a rest position to a cooking position where it is directly connected to the cooking chamber. In particular, in such a cooking position the upper surface  60  of the base  6  directly defines the cooking surface  10 , thus delimiting, together with ceramic glass and the wall of the burner  4 , the cooking chamber  1 . The movement of the base can be manual or automatic. In this case, it will be actuated by the same PLC that manages the oven. 
     In the rest position (shown in  FIG. 3 ) the base is in a position directly adjacent to a working plane  9 , the usefulness of which will be discussed hereinafter. 
     Between the rest position and the cooking position, the base can also take up a further stop position, corresponding to the preparation position of the pizza base. At this position (represented in  FIG. 4 ), i.e. in position juxtaposed over the base, pushing means are arranged such as a heated metal plate  7  (like for example steel) that, by moving in the direction perpendicular to the surface of the base, exerts pressure on a piece of dough arranged on the upper surface  60  of the base  6  itself. Such pressure determines the squashing of the dough that is reduced into a discoid shape to constitute a typical pizza base. The movement of the heated upper plate will also be managed by the PLC. 
     As stated above, the surface of the base  6  (which indeed defines the surface of the chamber  1  in the cooking position), is heated through an electrical resistance (not shown) arranged beneath it. Moreover, the radiation in the cooking step also contributes to the heating of the surface, determining an energy saving. 
     The heating of the cooking surface promotes the non-adhesion of the dough to the surface itself and also allows an even and regular cooking of the base. 
     Finally, at the preparation position of the base there are also delivery means  8  of the sauce, shown in isolation in  FIG. 5  and with a broken line in  FIG. 2 . These in particular comprise a spout  80  oriented at the preparation position in order to be able to pour the sauce directly onto the base once prepared. The spout sucks from a reservoir  81  through a pump  82 . 
     Hereinafter the method for obtaining the pizza ready to be served starting from the dough will be described in detail. 
     In the rest position the operator places the dough at the centre of the surface of the base  6 . In the case in which the base is automated, the operator controls the movement thereof, through the PLC, up to the preparation position. Here, the heated upper plate (also automated) squashes the dough to give it the discoid shape and make it a suitable base for a pizza. Possibly, it is possible to control the plate so that it stays pressing on the base long enough to carry out pre-cooking thereof, through the combined effect of the plate itself and of the heated base. 
     At this point the plate  7  lifts up and, through the delivery means, the sauce is dropped onto the pizza. From the interface of the PLC it is possible to choose the amount of sauce to distribute on the base and also decide the type of sauce. Such an operation can last from 5 to 10 seconds. Thereafter, the base is moved back into the rest position to allow the operator to add the condiments. 
     Then the base is moved into the cooking position obtaining the cooking of the pizza. Advantageously, the cooking times are very short, of the order of 45/50 seconds. 
     Once the pizza is cooked the base goes back into the rest position where the pizza is transferred by sliding to the auxiliary surface. For this purpose, the auxiliary surface  9  and the surface of the base  60  are arranged at the same height so that, when the surface of the base is in the rest position, the base of the pizza can be moved from the second to the first by simple sliding. In this way, it is possible to prepare many bases, by leaving them on the auxiliary surface, creating a reserve before proceeding to cooking. In the figures it is also possible to see a further surface  9 ′, bordering the auxiliary surface  9  that, being at a lower height than the auxiliary surface  9 , allows the pizza to be moved by sliding directly into the plate. 
     The oven according to the invention has numerous advantages. 
     In particular, thanks to the automated management of the burner by the PLC, the oven has low energy consumption and has optimised and controlled heating in every part thereof. Concerning this, by increasing the flame temperature, the ability to transmit heat in the cooking chamber by radiation increases. 
     Moreover, by managing the flame intensity based on the heat actually necessary to cook the product, the oven manages to minimise the production of residue like ashes and fumes. 
     The combined action of radiation and autonomous heating of the cooking surface  10  allows the cooking times to be sped up and energy to be saved. Moreover, since it is made from non-porous material, the surface is easy to clean and possible flour residue is completely eliminated (avoiding them being burned during cooking, emitting harmful substances). As well as this, the presence of the glass makes it possible to have a very low vault of the combustion chamber, i.e. very close to the glass itself, with obvious energy saving and an increase in the radiance value. 
     Moreover, given that the combustion chamber and the chamber of the burner are independent and separate from the cooking chamber, the cooking is healthier, since the product does not come into contact with the combustion residues, such as ashes and fumes, during cooking. The radiation effect determined by the ceramic glass in the cooking chamber accelerates the evacuation of the steam contained in the ingredients of the pizza, which cooks more quickly and stays crispier. 
     The pre-cooking of the base ensures better cooking and quality of the finished pizza. Moreover, the surface of the base beneath the sauce is also cooked evenly; the dehydration of the base due to the pre-cooking increases the ability of the base to absorb the sauce, avoiding the detachment of the toppings and of the sauce itself from the base. As a function of the squashing pressure of the plate  7  it is also possible to determine the diameter of the pizza base and its thickness. 
     Furthermore, when the oven is associated with the means for the automatic preparation of the pizza, the preparation and cooking times are drastically reduced, as is the work of the operator. The operator, indeed no longer has to constantly check the various steps of the preparation, meanwhile being able to take care of other tasks, like for example the preparation of the dough to be stored and used later in the preparation and cooking process. The dough is also handled little by the worker and therefore it will be possible to choose doughs even with less strong gluten meshes than those currently used that after cooking are difficult to digest and not crispy. 
     Possibly, it will also be possible to set the cooking times and the times of each of the single steps of the method described above manually, with the intervention of a worker. 
     As seen above, the movement of the base can be controlled automatically directly by the PLC or also by the worker by means of one or more pedals. For example, in a variant embodiment, there can be two pedals, a first of which controls the movement of the base from the rest position up to the squashing plate and the return to the return position, whereas a second pedal controls the movement of the base from such a rest position to the cooking position. Thanks to the PLC the oven can be switched on automatically through a timer or can be controlled remotely. 
     The movement of the base also allows faster and easier cleaning of the upper surface  60 . 
     Furthermore, the worker does not have to pay attention and continuously check the flame and is not subjected to the radiation therefrom. 
     The oven is thus small in size, such as to be able to be transportable, and, since it is automated, the quality of the pizza is indeed standardisable. 
     The present invention has been described up to now with reference to preferred embodiments thereof. It should be understood that there can be other embodiments that derive from the same inventive core, all of which are covered by the scope of protection of the claims given below.