Field of the invention

The present invention is directed to a device for in-line heating a fluid or a food product, particularly a fluid foam or a food foam, in order to deliver hot foams on demand, the heating being done by induction.

Background of the invention Fluid foams consist of two phases, an aqueous phase and a gaseous (air) phase. A fluid foam is a substance which is formed by trapping many gas bubbles in a fluid structure: producing a fluid foam involves not only the generation of these gas bubbles, but also the packing and the retention of these bubbles into the overall fluid structure in order to provide a stable foam.

Nowadays, there exists the trend of consuming a wider variety of coffee types, most of them containing considerably more milk than before. These new coffee types comprise very often milk foams, so providing a good quality foam which is stable for a long time is a present need. As a consequence, there is a strong need for a foam heating technology, particularly for a milk foam heating technology for a wide range of businesses, particularly involving beverage preparations. As for now, no practical cleaning solution exists and the consumer always has to clean parts of the machine through which milk circulated: this becomes a hassle when milk is involved because milk deteriorates rapidly with time and the system needs to be thoroughly cleaned very often, preferably after each use. Superior quality milk foam is also more and more required and the heating system has to be smartly designed so as not to decrease the foam quality and provide a superior in cup result, providing at the same time practical and easy cleaning ways. At present, there exist current systems which are able to provide superior quality milk foam: this milk foam is generated from cold milk and is then heated up at a later stage so that the creamy texture is kept stable for a longer period of time: this entrains the difficulty of being able to heat up the foam without degrading its texture. There are different ways of heating up cold milk foam known in the state of the art. Some use a heat transfer device, such as for example a thermoblock, which heats the milk foam once it has been produced. The problem of using such heat transfer devices is that they need to be deeply cleaned every day as milk fluid circulates within the heat transfer device, can deteriorate and be a source of contamination when staying longer in the device. Moreover, these systems are cleaned preferably by being rinsed using several times the amount of water they would require for a normal operation or dosing. Some other known systems use a direct flow of steam through the milk foam already formed in order to heat it up: however, this destroys the texture of the milk foam thus providing very low quality foam in cup.

Typically, existing heating solutions for fluids and fluid foams are bulky and not cleanable, such as for example those using a thermoblock. The fact that they cannot be cleaned makes it impossible to be used with products such as milk. On the other hand, existing solutions using direct steam injected to both foam and heat a fluid destroy the foam (particularly when talking of micro foams) with its high energy.

Other heating solutions known in the state of the art, for example those using removable electric heaters, present the drawback of using electric connectors which may be dangerous when being manipulated.

Induction heating technology is already used in cooking systems (induction pans, cookers, etc.) as per US 2014124502, for example, and is also starting to be used in several beverage systems. Example of these are heating beverage cans (as per US 2014197158 or JPH 10307957 for example), urns (US 2002083840) or stoves (CN 2031 16109). In all these known examples, heating is done in batches and in-line and/or controlled heating is not possible. It is therefore an object of the invention to provide a gentle, non-destructive and powerful heating system for superior quality milk foam on demand, having a controlled heating, which is easy to operate and to clean and maintain by a user.,

Summary of the invention According to a first aspect, the invention relates to an in-line heating device for heating a fluid and/or a food product and/or a fluid foam and/or a food foam, the device comprising a heating cartridge and a primary heating unit. The heating cartridge comprises an insert made of an electrically conductive material and being inductively heatable by an oscillating magnetic field provided by the primary heating unit; the heating cartridge further comprising an inner heating path through which the fluid and/or food product and/or fluid foam and/or food foam circulates; the heating path being arranged inside the insert so that fluid is heated while circulating through the path and before being delivered from the device.

Preferably, the heating provided depends on the distance between the primary heating unit and the insert. Typically, the primary heating unit and the insert are distanced by a separated heating space of a dimension allowing that the insert is at least partially positioned inside the magnetic field generated by the primary heating unit.

Preferably, the primary heating unit comprises a primary induction coil. Typically, the heating cartridge is configured removable from the rest of the device. Typically, the heating cartridge is configured having an external cylindrical shape: the insert is configured as a cylindrical sleeve matching the external shape of the cartridge.

Preferably, the cartridge comprises a heating insert with an inner shape configuring the heating path: the cartridge typically further comprises the insert configured as a sleeve surrounding the outer periphery of the heating insert. Preferably, the heating insert is made of a thermally conductive material, preferably aluminium. Typically, the insert is configured as a single ferromagnetic piece also configuring a heating insert with an inner heating path.

Preferably, the insert is configured comprising at least two complementary shaped bodies, the bodies configuring internally the heating path when brought together, and where the bodies are joined by means of joining means, allowing the assembly and disassembly of the bodies. Typically, the cartridge further comprises a nozzle housing arranged to externally surround both the heating insert and the insert, the housing being preferably made of a non-conductive material. Preferably, the cartridge comprises a heating insert configuring itself a heating path with spiral shape, made in a non-conductive material, the path being surrounded by an insert shaped as a sleeve.

According to a second aspect, the invention refers to a foaming machine providing a fluid foam and/or a food product foam, the machine being configured to receive an in-line heating device as the one described.

The foaming machine typically further comprises a temperature sensor arranged in such a way to have close contact with the insert of the cartridge.

According to a third aspect, the invention further refers to a system for providing a hot fluid foam and/or a hot food product foam, the system comprising a foaming machine as the one described and an in-line heating device also as described.

According to a fourth aspect, the invention refers to the use of such a system for foaming a fluid and/or a food product and further heating it.

Brief description of the drawings

Further features, advantages and objects of the present invention will become apparent for a skilled person when reading the following detailed description of non- limiting embodiments of the present invention, when taken in conjunction with the appended drawings, in which:

Fig. 1 shows a general cross-sectional view of the in-line heating device according to the present invention.

Fig. 2 shows a detailed cross sectional view of the in-line heating device of Figure 1 . Fig. 3 shows a detailed view of the arrangement of a temperature sensor in an in-line heating device according to the invention.

Fig. 4a shows a possible configuration of a heating cartridge used in an in-line heating device according to a first embodiment of the present invention.

Fig. 4b shows a possible configuration of a heating cartridge used in an in-line heating device according to a second embodiment of the present invention.

Figs. 5a-c show different views a possible configuration of a heating cartridge used in an in-line heating device according to a third embodiment of the present invention.

Figs. 6a-c show different views a possible configuration of a heating cartridge used in an in-line heating device according to a fourth embodiment of the present invention.

Detailed description of exemplary embodiments

According to a first aspect, the present invention is directed to a heating device 100 for heating a fluid and/or a food product and/or a fluid foam and/or a food foam, the fluid, food product or foams being provided by a machine to which the device is connected, as it will be further explained in more detail.

As represented in Figures 1 or 2, the device 100 of the invention comprises a heating cartridge 120 and a primary heating unit 1 10. The heating cartridge 120 comprises an insert 121 , made of an electrically conductive, typically a ferromagnetic material, and which is inductively heatable by an oscillating magnetic field provided by the primary heating unit 1 10.

Preferably, as shown in Figures 1 -2, the primary heating unit 1 10 comprises a primary induction coil which is responsible for the creation of an electromagnetic field. By supplying alternating current at high frequency inside this primary induction coil 1 10, an alternating electromagnetic field is generated in the surroundings. When approaching the insert 121 , made of an electrically conductive, typically ferromagnetic material, Eddy currents are generated in it so as to create an electromagnetic field that is opposed to the field generated by the primary induction coil 1 10. Depending on the resistivity of the insert 121 , these currents are used to heat it up using Joule losses.

The heating cartridge 120 further comprises an inner heating path 124 through which the fluid and/or food product and/or fluid foam and/or food foam circulates: as the heating path 124 is arranged facing the insert 121 or inside the insert 121 , the insert being inductively heated thanks to the alternating electromagnetic field created by the primary coil 1 10; therefore, fluid is heated while circulating through this path 124 and before it is delivered from the device 100 into a cup 10.

According to the invention, the heating cartridge 120 is configured removable from the rest of the device 100. Therefore, as shown for example in any of Figures 1 - 2, it can be removed and either can be disassembled and therefore made parts accessible for an easy cleaning, or the whole cartridge 120 can be made disposable, after having been used. As schematically represented in Figures 1 -2, the heating cartridge 120 is configured having an external cylindrical shape: the insert 121 is therefore made having typically the shape of a cylindrical sleeve matching the external shape of the cartridge. This would be understood better and in more detail, following the different embodiments of the heating cartridge 120 according to the invention, as further explained with reference to Figures 4a-b, 5a-c and 6 a-c.

Figure 4a shows a heating cartridge 120 according to a first embodiment of the invention. The cartridge 120 comprises a heating insert 125, here configured having several inner channels and conducts to intricate the flow of the fluid or foam flowing through it in order to increase the contact area with the product flowing. It is clear that this is only a possible shape of the insert and that different ones are possible and comprised within the scope of the present invention. This inner shape configures the inner heating path 124 through which the fluid or foam flows and is heated. The cartridge 120 further comprises an insert 121 configured as a sleeve and surrounding the outer periphery of the heating insert 125. Typically, the insert 121 is made of a ferromagnetic material (such as steel), while the insert 125 is made in a thermally conductive material, typically aluminium. The sleeve (insert 121 ) is heated thanks to the alternating electromagnetic field created by the primary coil 1 10.

In a general manner, according to the invention, the heating insert 125 is made of a thermally conductive material, while the insert 121 is made of an electrically conductive material. The idea behind is to cover the two main functionalities described: the insert 121 needs to be made of a material which can be inductively heated thanks to the alternating electromagnetic field created by the primary coil 1 10. On the other hand, the heating insert 125 needs to be made of a material allowing a good thermal transfer through it in order to heat the product flowing through or inside it. Aluminium is preferred as the thermally conductive material as it allows a very good dispersion of heat through it, in a short time, therefore making the heat transfer effective. The preferred electrically conductive material for the insert 121 is a ferromagnetic material, such as steel, allowing the generation of Eddy currents in it creating an electromagnetic field opposed to the field created by the primary coil. The same material can be used for both inserts, 121 and 125; however, preferred embodiments of the invention use different materials for these inserts.

Figure 4b shows another configuration of the heating cartridge 120 according to a second embodiment of the invention, where the path 124 is directly made in the heating insert 125. In this embodiment, the heating insert 125 is made of one single piece and is made of a ferromagnetic material or an electrically conductive material. The external part of the insert, configured having a cylindrical shape, is also used as the insert 121 itself, without the need of providing a further outer sleeve as for example used in Figure 4a of the first embodiment of the invention. Eddy currents circulate in the heating insert 125, without the need for a dedicated sleeve. A possible configuration comprising a plurality of holes is shown (different configurations are also possible): the fluid or food or foam circulates through these holes, configuring internally the path 124, and is heated by contacting the outer walls of the insert 125, which are heated thanks to the alternating electromagnetic field created by the primary coil 1 10.

This second embodiment (Figure 4b) presents the advantage of cleaning only one piece (the insert 125) removed from the rest of the device 100, after the fluid passes through and in case the cartridge 120 is not made disposable. In the embodiment of Figure 4a, there are two pieces to clean after use: the insert 121 (the inner wall of it having been in contact with the fluid or foam) and the insert 125 through which the fluid or foam has circulated. Also, the cartridge 120 can be made disposable as well in the first embodiment. It is also possible that both parts are mechanically joined: in this case, you remove the whole cartridge 1 20, without separating any part, and you clean the inside of it, which is the only place through which product or fluid circulated.

Figures 5a-b-c show different views of a heating cartridge 120 according to a third embodiment of the present invention. The cartridge 120 comprises a heating insert 125 which has an inner spiral side, configuring the path 124 through which the fluid or foam circulates. Other different executions (not spiral) would be possible, but this has found to be one of the preferred ones. The insert 125 is made in a thermally conductive material, typically aluminium, allowing a very good heat dispersion. External to it, the insert 121 (typically a ferromagnetic material) covers the external part and is preferably configured with the shape of a sleeve, to be in close contact with the external walls of the insert 125 and therefore heat the fluid or foam through.

Preferably, the insert 125 is configured having two complementary shaped bodies which, once brought together, configure internally the heating path 124. The bodies can be brought together by means of different joining means or joints, but always easy means allowing their assembly and disassemble in order to be able to access their inner part (the path 124) for cleaning.

In the embodiments shown in Figures 4a-b, or Figures 5a-c, the cartridge 120 further comprises a nozzle housing 122 which is arranged externally and surrounding the heating insert 125 and the insert 121 . This housing 122 is typically made in a non- conductive material, preferably made in plastics (more preferably in silicon), so that it isolates the rest of the metallic parts, namely the two inserts 125 and 121 . Also, it covers externally the cartridge 120 and therefore constitutes an external housing allowing its removal from the rest of the device 100. This part 122 also plays the role of sealing the cartridge 120 with the upper part of the machine and the rest of the fluidic system (fluid inlet).

Finally, Figures 6a-b-c represent different views of a heating cartridge 120 according to a fourth embodiment of the present invention. In this fourth embodiment, the cartridge comprises a unique part configuring both the heating path 124 and the heating insert 125, made in non-conductive material, typically in plastics, preferably in silicon. Externally, there is the insert 121 configured as a sleeve, made in ferromagnetic material, heated thanks to the coil 1 10 and allowing heating the fluid or foam through the path 124. As the path through which the fluid flows is made in plastics, non-conductive, and is heated by contact with the outer wall facing the path (inner walls of the insert 121 ), it is clear that the heating is less efficient than in other executions; however, cleaning is performed easily as there is one part less configuring the cartridge, only two parts configuring it, the insert 121 and the part configuring at the same time the nozzle housing, the heating path and the heating insert.

The heating device 100 of the invention is capable of delivering hot fluid or hot fluid foam on demand, the fluid or the foam being provided by the machine to which the device is connected, as shown in Figure 1 . As heating is based on induction technology, the system is safer for the user as there is no electric contact between the cartridge and the heating unit (coil). Further, there is no contact between the product (fluid and/or foam) and the machine, so there is no problem of contamination and delicate fluids such as milk can be used advantageously. In the first embodiment of the cartridge 120 (Figure 4a) the parts in contact with the product are the inserts 125 and 121 , which can be removed from the rest of the cartridge 120 and can be separated and therefore cleaned. Another possibility would be to make the cartridge disposable. In the second embodiment, represented in Figure 4b, the part in contact with the fluid or foam is the insert 125 (configured as unique part) and this part can also be disassembled and cleaned (or it is made disposable).

In the third embodiment of the invention, as shown in Figures 5a-b-c, there is only one part being in contact with the fluid or the foam, the heating insert 125. In this case, this insert is configured in such a way that it can be removed from the rest of the cartridge 120 and it can be separated in two parts, allowing access to its inner path 124 through which the product circulated. Therefore, an easy cleaning of it is allowed, and further joining means allow its later assembly for re-use. Another option would also be to make this part of the whole cartridge disposable.

Finally, in the fourth embodiment of the invention, represented in Figures 6a-b- c, the fluid or foam circulates through the path 124 (made in the insert 125 itself), so the parts in contact with product are the insert 125 itself and the outer insert 121 (specifically, its inner wall). As the two parts can be separated, they can be conveniently cleaned. Again, another possible arrangement would be to make the cartridge disposable. Further advantages of the device of the invention are that it is made having a compact design, further allowing a cartridge temperature control (this would be explained later, with reference to the machine to which the device is connected) and also allowing the heating of cold foam, which provides a higher quality of foam, compared to hot foam creation. Also, traditional ways of heating a fluid or a foam using for example a thermoblock require a higher inertia than the solution proposed with the device of the invention: this makes that longer time is needed for effectively being able to have the thermoblock prepared for heating the fluid/foam, whereas in the case of the invention, it is the insert 121 the part that needs to be heated; this part is thin and has a low inertia, thus allowing the device be ready in a short time to heat the fluid flowing through, therefore allows quick heating operations.

According to a second aspect, the present invention is directed to a foaming machine 200 as schematically represented in Figure 1 . The machine 200 can be a standard or known machine providing a fluid or a food product, particularly a food foam or a fluid foam to the heating device 100, the device being in charge of heating the product delivered by the machine before finally dispensing it into the cup 10. As shown in detail in Figure 3, the machine 200 comprises a temperature sensor 202 arranged in such a way to have close contact with the insert 121 of the cartridge 120. As the induction technology used is fast and powerful, there is the need to control the temperature of the product in order not to overheat it. This can be made either by measuring the product temperature or the heating element temperature. The second case is the one used by the invention. The machine 200 is further provided with a sensor support 203 to place conveniently the temperature sensor 202 so that there is a close contact between the sensor 202 and the insert 121 so that the temperature of the heating element can be correctly determined. Other temperature sensing technologies can be used (e.g. infra-red).

As shown in any of Figures 1 or 2, the cartridge 120 and the device 100 of the invention are typically arranged in the head 201 of the machine 200.

According to a third aspect, the invention further relates to a system 300 for providing a hot fluid foam and/or a hot food product foam. The system 300 comprises a machine 200 and an in-line heating device 100 as previously described.

Some of the main advantages of the device of the invention are the following: • on-demand heating system based on induction technology; ^• removable and cleanable cartridge (only part in contact with the product);

• safe construction for user;

^• cartridge temperature control;

• compact design;

• allows cold foam heating (better quality than hot foam creation);

^• no contact between product and machine;

^• high reactivity thanks to high power density and low inertia;

^• scalable technology.

Although the present invention has been described with reference to preferred embodiments thereof, many modifications and alterations may be made by a person having ordinary skill in the art without departing from the scope of this invention which is defined by the appended claims.