TECHNICAL FIELD

The present invention relates to a heating-cooling device for cooling or heating food or other substances. Additionally, the invention relates to a hermetic closing kit comprising said device and a closing element. The invention further relates to a method for manufacturing the device.

PRIOR ART

Devices able to vary the temperature within determined containers without the need to be connected to the power grid can be useful in many situations. For example, for transporting and storing drugs, food, drinks or any other perishable substance in environments in which a connection to the power grid is impossible.

Systems of this type are known in various sectors and can vary from very simple and cheap structures to more complex and expensive structures. Back in ancient times, for example, the use of two terracotta pots placed inside one another and separated by wet sand was known for the purpose of keeping the substances contained in the most internal pot cool. Although it is reliable and simple to perform, this system is not very efficient since it determines a temperature reduction of just a few degrees centigrade with respect to ambient temperature.

As an evolution of this structure, more elaborate and efficient systems have been developed, still using as the fundamental element their independence from a connection to the power grid. For example, a portable solar-powered fridge is known which is comprised of two metal cylinders, one inserted inside the other and separated by organic material like sand or wool impregnated with water. The heat of the sun's rays allows water to evaporate leading to the cooling of the internal cylinder followed by a transfer of heat to the outside. Despite it being possible through a mechanism of this kind to even reach a temperature of 6 degrees centigrade, this device cannot operate endlessly since constant refilling of the evaporated water is necessary, as well as the continuous presence of the sun.

To obtain more prolonged performance the sun's energy has been exploited in a different way using more innovative technologies. For example, photovoltaic systems are known applied to real portable fridges such as to obtain ongoing performance even reaching temperatures below zero.

However, systems of this kind are sometimes very bulky and heavy and do not always guarantee the maintenance of the organoleptic properties or integrity of the chemical/physical characteristics of the foods or of the substances contained due to, for example, the presence of coolant gases in traditional fridges.

It is the object of the present invention to partly or totally overcome the drawbacks mentioned above in relation to known systems and to provide a heating-cooling device that is more effective and functional.

DESCRIPTION OF THE INVENTION

A heating-cooling device, a hermetic closing kit and a method for manufacturing the device are presented herein, according to the independent claims.

The device according to the present invention comprises a container having a continuous containment wall that extends in a single body and defines an inner containment region with an opening. The containment wall comprises an edge portion in proximity to the opening and is formed by a first layer, or outer layer, and a second layer, or inner layer facing towards the inner containment region. The first layer is separated from the second layer so as to form a gap region, inside which vacuum is created. In particular, the device further comprises at least one electric generator external to the container for producing electrical energy and at least one electric charge accumulator external to the container for storing the energy produced by the generator.

Furthermore, the device comprises at least one thermoelectric device positioned inside the gap in contact with the inner layer of the containment wall for transferring the heat relative to the inner containment region and a control unit positioned external to the container and connected at least to the electric generator, to the electric charge accumulator and to the thermoelectric device for managing the passage of current through the thermoelectric device so as to determine, according to requirements, the cooling or heating of the inner containment region.

Thanks to the presence of a control unit that manages an energy unit (electric generator and electric charge accumulator) and a heat exchange unit (thermoelectric device), it is possible to use the device according to the present invention both to cool and to heat one or more of the substances present in the container of the device.

Furthermore, the particular configuration of the heat-insulating container that essentially comprises a wall having two layers forming a gap inside which vacuum is created, makes the device according to the present invention ecological and non-toxic. In fact, unlike traditional refrigerating systems, harmful gases are used such as freon or ammonia that affect the flavours and are pollutants as well as potentially being toxic. Additionally, as well as making the device independent from any connection to the power grid, the energy unit allows temperatures to be reached that can go below 0°C and be inverted to reach 50°C, according to the number of thermoelectric devices applied.

The thickness of the layers of the containment wall can have a value of a few millimetres, comprised between 1 millimetre and 6 millimetres, in particular about 2-3 millimetres. Obviously the thickness may be higher, for different needs.

For this reason, the device can have a contained weight and can be easily transported. Therefore, it is feasible to conform the container of the device so as to make it suitable for example for the transport of food or other materials that need to be kept at a determined temperature, or heated or cooled. Specifically, the container can take the form of a box or trunk equipped with relevant handles or shoulder straps, easy to transport. The refrigerating container can, also, be used as an interior furnishing item with a refrigerating function: in various sizes and shapes, with decorations of any type, the fridge becomes "interior design" with a sustainable cold chain function, without any power grid.

Advantageously, the container of the device is only made of ceramic material. Materials with similar resistance and thermal conductance properties can be used.

Therefore, standard moulding processes can be used for creating any shape and size. In an embodiment of the present invention, the first and the second layer are made in particular of hard non-porous feldspathic porcelain.

Porcelain is an excellent material for the conservation of the organoleptic properties of the substances contained.

Furthermore, thanks to the hardness level of porcelain, unlike other materials, the continuous containment wall is able to withstand atmospheric pressure and possible impacts, although there is a vacuum inside the gap. Porcelain acts in this case both as an electrical insulator and as an insulation system through, for example, a special nanosphere and/or network structure internal to the ceramic material for the purpose of creating layers of different densities.

In particular, the porcelain used for the present invention comprises kaolin, feldspar and quartz.

Naturally, it is possible to use other materials with similar characteristics to ceramic and/or porcelain in terms of thermal conduction and resistance/hardness. According to the material used, the device will therefore be made according to different procedures suitable for the processing of the material chosen.

In a further embodiment of the invention, the electric generator can comprise a film of transparent photovoltaic material applied to the outer layer of the containment wall. The film can have a thickness comprised between a few μηη , up to 1 and 3 mm and can be applied through a spray application. This has the enormous advantage of being able to provide a compact and relatively light device.

In an embodiment of the device according to the present invention, the connection between the electric generator and the charge accumulator can take place through electrodes integrated into the outer layer of the containment wall.

The electrodes can comprise conducting metals such as, for example, tungsten or the like, which have a high melting point (for example higher than the firing temperature of porcelain which is 1350 °C) and that become a single body with the containment wall.

Alternatively, the electrodes may be rheophores that are inserted in pre- established holes in the containment wall, becoming a single body with this wall with the re-firing of adhesives at temperatures that are not high. In an embodiment of the invention, the electric charge accumulator comprises a rechargeable battery.

In this way, the device is supplied through a continuous 12 volt source powered by solar energy.

In particular, in an embodiment of the invention, the thermoelectric device comprises a Peltier cell.

This is used to transfer heat with respect to the inside of the container based on a flow of electric current that crosses it. Advantageously, the device can comprise a plurality of thermoelectric devices, i.e. Peltier cells connected in series or in parallel according to the optimal configuration.

Based on the direction of the electric current applied, the Peltier cell can be used for heating or for cooling the inner layer of the containment wall with which it is in contact.

In particular, the device can be configured so that the Peltier cell forms a single body with a region of the inner layer of the containment wall. This is made possible when the containment wall of the container is made with a double layer of ceramic material. In fact, since a Peltier cell comprises molten semi-conducting materials in special ceramics, it is feasible to provide a structure in which a surface of the Peltier cell coincides with the inner layer of the containment wall or at least a part thereof.

In an embodiment of the invention, the thermoelectric device can further comprise a heat sink positioned inside the gap in contact between a surface of the thermoelectric device and the outer layer of the containment wall.

The heat sink may comprise one or more thin metal plates, for example copper or aluminium, which extend from a surface of the Peltier cell to the outer layer of the containment wall, inside the gap.

In another embodiment, the device can further comprise at least one heat sensor positioned inside the gap in contact with the inner layer of the containment wall and connected to the control unit for reading the temperature inside the container.

According to an embodiment, the control unit can comprise a microprocessor and a wireless unit for managing the device remotely.

In this way, the sensor associated with a mobile application allows temperature updates to be received and for it to be controlled remotely. A meal stored in the portable device according to the present invention can be heated without changing container, simply by remotely activating the inversion of the current direction in the thermoelectric device through the control unit.

Advantageously, associated with the control unit, there may be an auxiliary current socket, for example USB.

In a further embodiment of the invention, the ceramic material of the first and the second layer prevalently comprises feldspar, kaolin and quartz defining a determined density of the material, which is variable on the surface of the inner and outer walls for controlling heat dissipation.

In an embodiment of the invention, the first layer is never in direct contact with the second layer and the container further comprises a junction element made of ceramic material positioned at the edge portion of the containment wall for an indirect connection between the first and the second layer.

In this way, the container can be conceived as the set of two receptacles of roughly the same shape coupled to one another, for example one inserted inside the other. The junction element is therefore used to connect the two separate receptacles and form a single container. If the container were shaped like a cup, the two receptacles that would represent the inner and the outer layer of the containment wall would have the shape of two cups, such that the outer cup must be able to totally contain the inner one, without however being in contact with it so as to form a gap between the surfaces of the two receptacles. The junction element can therefore assume the shape of a ring that is interposed in the space present between the upper edges of the two cups.

In particular, in an embodiment of the invention, the ceramic material of the junction element comprises a spongy reticulated material or nanospheres made of hard feldspathic porcelain, defining a material density which is lower with respect to the density of the first and the second layer.

Since a low material density determines a reduction in heat conduction, the presence of a junction positioned on the edge portion of the containment wall having a lower density than the rest of the container, ensures that the substance contained inside the container maintains the temperature constant for longer even in the absence of an insulating plug or lid.

In an additional or alternative embodiment of the present invention, the containment wall comprises at least a region of low heat conduction at the edge portion, in which the ceramic material of the first and second layer in said region comprises a spongy reticulated material or nanospheres made of hard feldspathic porcelain defining a material density which is lower with respect to the density of the material outside said region.

In a similar way to what has been highlighted for the junction element with a low density, the low heat conduction region can further increase the heat maintenance effects inside the container, preventing the transfer of heat from and towards the inside of the container.

This can be performed during the firing step of the two layers by changing the material at a determined time inside the mould, for example.

The hermetic closing kit according to the present invention comprises a heating-cooling device as described previously and a closing element to be positioned at an edge portion of the containment wall of the container of the device in proximity to the opening for closing said opening of said container. The closing element is comprised of two layers of ceramic material separated from one another and defining a gap within which vacuum is formed. To seal the contact part at least one element made of polymeric material, or the like, could be provided, coupled to the closing element, wherein the sealing element is in direct contact with the containment wall of the container for hermetically closing the opening. The sealing element can be made of soft polymeric materials such as silicone.

The closing element can be a separate element from the device and therefore from the container or be connected to it through a system, for example a hinge system. In the latter case, the closing element can operate as a panel or door that opens and closes again easily through a coupling and decoupling mechanism.

In this way, it is possible to obtain a perfectly insulating container for maintaining the temperature of the substance contained even for very long times.

The method according to the present invention for providing a heating- cooling device as described previously, comprises the steps of creating a first layer, or outer layer, through a firing process at a temperature T1 , said first layer defining the outer continuous containment wall comprised in the device and creating a second layer, or inner layer, through a firing process at a temperature T2 equal to T1 , said second layer defining the inner continuous containment wall of the container comprised in the device. The second layer is separated from the first layer so as to form a gap region.

The method further comprises the step of applying at least one thermoelectric device inside the gap in contact with the inner layer of the containment wall and creating a junction element through a firing process at temperature T3 and hermetically fixing said junction element at an edge portion of the containment wall of the container at an opening for an indirect connection between the first and the second layer.

In an additional or alternative embodiment of the present invention, in the event of using non-ceramic materials, the production process of walls with similar properties will take place according to the methodologies typical of the material (metals, special plastics, etc.).

Furthermore, the method comprises the step of applying an energy generator, a charge accumulator and a control unit external to the container, in which the connection between the control unit and the thermoelectric device takes place through electrical connection means, said means passing through at least one through hole on the outer layer of the containment wall.

Finally, the method comprises the step of creating vacuum inside the gap formed between the first and the second layer.

The step of hermetically fixing the junction element to the containment wall takes place through a firing process at temperature T ₄ much lower than Ti , or through a gluing or welding process, or through insertion in the hermetic closing O-ring in a vacuum chamber.

Advantageously, the firing of the junction element can be performed within an induction oven so as to delimit the firing to the junction region preventing the re-firing of the rest of the container. This is extremely useful in the event in which the container is provided with areas of different density which, with a re-firing process, could emit gas into the containment wall. Furthermore, the presence of electronic and metal components within the gap ensures that any re-firing process of some areas of the container is limited to said areas where there is actually no circuit element present. The step of establishing the connection between the electric generator and the electric charge accumulator takes place through electrodes integrated into the outer layer of the containment wall.

In particular, the creation of the vacuum takes place by means of extracting air through the hole present on the outer layer of the containment wall and the maintenance of the vacuum within the gap takes place through a closing means that hermetically closes the hole once the vacuum has been created.

The closing means is held in position by a pressure variation exerted on the closing means by the vacuum created within the gap and the electrical connection means crosses the closing means through rheophores.

What has been highlighted up to now for the characteristics of the device can also be considered valid in relation to the method for manufacturing said device.

In particular, the firing temperatures Ti and T2 in relation to the creation of the first and the second layer, are comprised between 1200°C and 1350°C, in the case of porcelain. While the firing times are material preparation cycles that vary from a few hours to 18 - 24 hours for an entire hard feldspathic porcelain cycle.

The pressure value in the gap passes from environmental pressure, to 0.00001 mbar to absolute vacuum.

These and other aspects of the present invention will become more apparent in light of the following description of some preferred embodiments described herein below.

Fig. 1 shows a schematic representation of a device according to the present invention; and

Fig. 2 shows a flow diagram of the steps of the method for manufacturing the device.

Figure 1 shows the heating-cooling device 90 having the shape of a cylinder. The device 90 comprises a container 1 having a continuous containment wall 3 that extends in a single body and defines an inner containment region 8 with an opening 4. Figure 1 shows in particular how the opening 4 is present on the upper portion of the container 1 opposite the base thereof.

The containment wall 3 comprises an edge portion 6 in proximity to the opening 4 and is formed by an outer layer 10 and an inner layer 20. These two layers respectively determine an outer wall in contact with the external environment (outer layer 10) and an inner one facing towards the inner containment region 8 (inner layer 20). The two layers are separated from one another so as to form a gap 30. A vacuum is created inside the gap. The outer layer 10 comprises at least one hole 22 positioned on the base of the container 1 for the passage of air and a closing means 40 for hermetically closing the hole 22 once the vacuum has been created inside the gap 30.

Both the first and the second layer 10, 20 are made of hard feldspathic porcelain. In this way, it is possible to obtain a highly resistant container 1 and to function effectively as a heat insulator. In fact, the hardness of porcelain guarantees the excellent resistance of the walls, even in conditions in which there is a vacuum inside the gap. Furthermore, the established production techniques of porcelain ceramic, guarantee easy production of containers of any shape and size.

In another embodiment, different materials from ceramic and porcelain can be used that have similar performance.

The device 90 further comprises an electric generator 41 in the form of a transparent and organic photovoltaic film applied to the outer surface of the containment wall 3 and a battery 42 that is rechargeable through the generator 41 external to the container 1.

Still external to the container 1 , the device provides a control unit 44 connected to the battery 42 and to the photovoltaic coating 41 through electrodes 48 and a wireless unit 47 for remote communication. The wireless unit 47 can comprise an Access Point board. Within the gap 30, the device 90 comprises at least a plurality of Peltier cells 43 (two are shown in the figure) in contact with the inner layer 20 of the containment wall 3. Each Peltier cell 43 is associated with a heat sink 45 interposed between a

surface of the cell 43 and the outer layer 10 of the containment wall 3.

Inside the gap 30 a heat sensor 46 is also provided in contact with the inner layer 20 of the containment wall 3.

Both the Peltier cells 43 and the sensor 46 are electrically connected with the control unit 44 through connection cables 49 that pass through the hole 22 and the closing means 40.

Figure 2 finally shows a flow diagram that describes the method 200 for manufacturing the device 90.

The method 200 is characterised in that a first layer 202, or outer layer, is created, through a firing process at a temperature Ti , a second layer 204, or inner layer, is created, through a firing process at a temperature T2 equal to Ti and the vacuum 214 is created inside the gap 30 formed by the two layers 10, 20.

In relation to the creation of two layers, this happens separately 202, 204 with two distinct firing processes. On the outer wall of the inner layer 20 the Peltier cells 43 are applied 206. Where present, the sensor 46 is also applied. Before creating the vacuum inside

the gap 30, after the creation of the two layers 10, 20 and the application of the devices 43 and 46, a junction element 208 is created through a > firing process at temperature T3 (equal to Ti) and the junction element is hermetically fixed 210 at the edge portion 6 of the containment wall 3 for an indirect connection between the first and the second layer 10, 20.

In relation to the creation of the vacuum 214, this takes place by means of the extraction of air 216 through a hole 22 present on the outer layer. The maintenance of the vacuum 218 inside the gap 30 takes place by means of a closing means 40 that hermetically closes the hole 22 once the vacuum is created. The closing means is held in position by a pressure variation exerted on this closing means by the vacuum created within the gap. In particular, the electrical connection means 49 that connects the Peltier cells 43 and the sensor 46 outside the gap 30 crosses the closing means 40 through rheophores.

Prior to or following the creation of the vacuum 214, the method according to the present invention envisages the step of applying an energy generator, a charge accumulator and a control unit external to the container 212, in which the connection between the control unit and the thermoelectric device takes place through an electrical connection means 49, said means passing through at least one through hole 22 on the outer layer 10 of the containment wall 3.

A person skilled in the art can introduce numerous further modifications and variations to the container, kit and method described hereinabove for the purpose of meeting additional and contingent needs, all of which, however, remaining within the scope of protection of the present invention as defined by the claims attached hereto.