Heating device for machine for preparing hot beverages

Abstract

A heating device (1), in particular a flow-through heater, for a machine for preparing hot beverages, comprising:-a metal body (2) made of aluminum or an aluminum alloy; -at least one electric heater (3) arranged in the metal body (2); -a conduit (4) for the passage of an edible liquid to be heated, in particular water, delimited by the first inner surface (21) of the metal body (2); wherein the metal body (2) comprises a first end portion (24a) and a second end portion (24b), which respectively define an initial extension and a final extension of the conduit (4); wherein the first end (24a) and the second end (24b) have respective outer surfaces (241a, 241b) and are adapted to be inserted into respective tubes (9); wherein the first inner surface (21), the outer surface (241a) of the first end (24a) and the outer surface (241b) of the second end (24b) are coated with respective coatings, in particular coatings suitable for food contact.

Description

Technical Field

[0001] The present invention relates to the field of beverage preparation devices, in particular domestic beverage preparation devices.

[0002] In particular, the invention relates to a heating device, more particularly to a flash exchanger or heater or flow-through heater suitable for heating a liquid flow, in particular water, for preparing a beverage. Background Art

[0003] Machines for preparing hot beverages such as coffee are very common.

[0004] Such a machine is provided with heating means suitable for heating water for preparing the beverage.

[0005] One type of heating device is known as a flow-through heater (FTH), or a flow heater or a transient heater, in particular a transient flow heater. A flow-through heater is particularly suitable for heating a stream of water, ie for heating water as it flows in a conduit of the device.

[0006] A heating device of the FTH type comprises a metal body, a conduit for the liquid to be heated and one or more heating elements which generate heat by the Joule effect.

[0007] It is desirable to manufacture the metal body from aluminum or an aluminum alloy since this is a material that conducts heat well.

[0008] However, for health reasons, the aluminum metal body should not come into direct contact with the liquid to be heated.

[0009] Therefore, the heating device comprises inserting a stainless steel tube into the metal body so that the liquid is in contact with the stainless steel tube and not with the metal body. The steel tube is usually brazed to the metal body.

[0010] However, the use of steel pipes has several disadvantages, including: reduced energy efficiency; limestone adheres to the steel pipes; and greater equipment production complexity and longer construction time.

[0011] Furthermore, the steel pipe does not provide any electrical insulation between the liquid and the heating element.

[0012] Therefore, there is a need to overcome the limitations of existing technologies. Summary of the invention

[0013] The object of the present invention is to provide a heating device, in particular a heating device of the FTH type, for a machine for preparing beverages which are particularly safe for health.

[0014] Another object of the invention is to create a FTH type heater that is safe for health and energy efficient.

[0015] Another object of the invention is to create a FTH type heater that is safe for health and easy to produce.

[0016] The present invention achieves at least one of these objects, as well as other objects that will become apparent from the description of the invention, by a heating device, in particular a flow-through heater, for a machine for preparing hot beverages, comprising:

[0017] - a metal body made of aluminum or an aluminum alloy;

[0018] - at least one electric heater arranged in the metal body;

[0019] - a conduit for passing an edible liquid to be heated, in particular water, the conduit being defined by the first inner surface of the metal body;

[0020] wherein the metal body comprises a first end portion and a second end portion, which respectively define an initial extension portion and a final extension portion of the conduit;

[0021] wherein the first end portion and the second end portion have corresponding outer surfaces and are adapted to be inserted into corresponding tubes;

[0022] The first inner surface, the outer surface of the first end portion and the outer surface of the second end portion are coated with corresponding coatings, in particular, coatings suitable for food contact.

[0023] The invention also relates to a machine for preparing beverages according to claim 12 .

[0024] Advantageously, the device according to the invention allows the use of a metal body made of aluminum or an aluminum alloy, which defines a duct through which the liquid passes and maximizes food safety, ie safety for human health. In fact, the coating prevents direct contact between the liquid and the aluminum or aluminum alloy.

[0025] In particular, advantageously, the coating of the first inner surface prevents the metal of the metal body from coming into contact with the liquid flowing in the conduit.

[0026] Furthermore, it is particularly advantageous if the outer surface of the first end and the outer surface of the second end are also provided with a corresponding coating. In fact, when the ends are inserted into the corresponding tube, liquid can fill the gap between the outer surface of each end and the corresponding tube. Thus, the coating also prevents direct contact with the aluminum or aluminum alloy in these areas.

[0027] In particular, each coating is made of a polymer material or a sol-gel.

[0028] Preferably, each coating is made of or essentially consists of the following materials: polyamide (PA), polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), polyurethane (PU), polyester, epoxy material, silicone resin, sol-gel, amorphous silicon, amorphous silicon oxide, silicon nitride, silicon dioxide, polycrystalline silicon, fluorocarbon, organic fluorine.

[0029] It is particularly preferred that each coating consists of polyamide (PA) or consists essentially of polyamide (PA).

[0030] In particular, polyamides allow a simple and rapid production process for the device, which is also suitable for contact with foodstuffs. In particular, polyamides allow easy and rapid manufacture of the device, without requiring pretreatment of the surface to be coated, and allow bending of the conduit after the coating operation, thus avoiding damage to the coating.

[0031] The following materials are particularly advantageous, since they are suitable for coating difficult-to-reach surfaces: amorphous silicon, amorphous silicon oxide, silicon nitride, silicon dioxide, polycrystalline silicon, fluorocarbons, organic fluorines.

[0032] Advantageously, the coating allows increasing the resistance to adhesion to limestone.

[0033] Further features and advantages of the present invention will become more apparent from the detailed description of exemplary but non-exclusive embodiments of the present invention.

[0034] The dependent claims describe particular embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In the description of the invention, reference is made to the accompanying drawings, which are provided by way of non-limiting examples, in which:

[0036] Figure 1 shows a perspective view of a device according to the invention;

[0037] Figure 1A Schematically shows Figure 1 a cross-sectional view of a detail of the device with the end of the device inserted into the tube;

[0038] Figure 2 Shows Figure 1 Section AA;

[0039] Figure 3 Only shown Figure 1 Section AA of the metal body of the device;

[0040] Figure 4 Shows Figure 1 Another perspective of the installation;

[0041] Figure 5 Shows Figure 1 Floor plan of the installation.

[0042] The same elements or components have the same reference numerals. DETAILED DESCRIPTION

[0043] With reference to the accompanying drawings, a non-limiting exemplary embodiment of a device 1 or a heating device of a machine for preparing hot beverages according to the present invention is described.

[0044] In particular, the device 1 is of the flow-through heater type, or of the instantaneous heater or flow heater type.

[0045] In particular, the device 1 is suitable for being installed in a machine for preparing hot beverages. By way of example and not limitation, the machine is used for preparing coffee.

[0046] In all embodiments, the device 1 comprises

[0047] - a metal body 2 made of aluminum or an aluminum alloy;

[0048] - at least one electric heater 3 arranged in the metal body 2;

[0049] a duct 4 for passing an edible liquid to be heated, in particular water, the duct 4 being defined by a first inner surface 21 of the metal body 2;

[0050] The metal body 2 includes a first end 24a and a second end 24b, which respectively define an initial extension portion and a final extension portion of the conduit 4;

[0051] The first end portion 24a and the second end portion 24b have corresponding outer surfaces 241a, 241b and are suitable for being inserted into the corresponding tube 9;

[0052] The first inner surface 21, the outer surface 241a of the first end portion 24a and the outer surface 241b of the second end portion 24b are coated with corresponding coatings, in particular, coatings suitable for contact with food.

[0053] The device 1 is particularly suitable for heating a flow of water, more specifically it is suitable for heating water while it flows in a conduit 4 of the device 1 .

[0054] The coatings are particularly suitable for contacting the edible liquid to be heated (or heated by the device 1 in the case of the coating of the end 24b), in particular they are suitable for being wetted by the edible liquid to be heated (or heated by the device 1 in the case of the coating of the end 24b).

[0055] In particular, the coating is made of a different material than the metal body 2 .

[0056] The coating is preferably made of the same material.

[0057] The coatings preferably have the same thickness.

[0058] Each coating is preferably made of a polymer material or a sol-gel.

[0059] Preferably, each coating is essentially made of or is made of one of the following materials: polyamide (PA), polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), polyurethane (PU), polyester, epoxy material, silicone resin, sol-gel, amorphous silicon, amorphous silicon oxide, silicon nitride, silicon dioxide, polycrystalline silicon, fluorocarbon, organic fluorine.

[0060] It is particularly preferred that each coating consists essentially of polyamide (PA) or consists of polyamide (PA).

[0061] The polyamide is carefully selected. In fact, the inventors have found that polyamide has various advantages.

[0062] In particular, polyamide allows facilitating the production process of the device 1. In fact, polyamide does not require pretreatment operations on the surface to be coated. In particular, polyamide does not require mechanical operations on the surface to be coated, such as grinding the surface to be coated to increase its roughness.

[0063] Polyamide also has suitable mechanical properties, so that in order to obtain a conduit 4 having one or more curved extensions, the inner surface of the metal body 2, which is straight, can first be coated with polyamide; then the metal body 2 can be bent so that the conduit 4 has one or more curved extensions. In particular, the polyamide coating is not damaged by bending the inner surface 21 (coated with polyamide) defining the conduit 4. The same applies to the case of obtaining curved end extensions 24a, 24b.

[0064] Furthermore, polyamide advantageously allows coating of conduits 4 having an inner diameter of 2 to 10 mm, for example 4 to 7 mm. In other words, polyamide advantageously allows coating of conduits 4 having a very small inner diameter.

[0065] The following materials are particularly advantageous, since they are suitable for coating difficult-to-reach surfaces: amorphous silicon, amorphous silicon oxide, silicon nitride, silicon dioxide, polycrystalline silicon, fluorocarbons, organic fluorines.

[0066] In particular, the coating is made of a material approved for food contact.

[0067] “Approved for food contact” preferably means approved by one or more entities, preferably by the FDA (Food and Drug Administration) and / or by the BfR (Bundes inst itut für Risikobewertung) and / or other agencies.

[0068] The coating preferably also has non-stick properties, particularly with respect to limestone.

[0069] Preferably, the thickness of each coating layer is from 2 to 100 μm, preferably from 5 to 25 μm.

[0070] Preferably, substantially the entire inner surface 21 is provided with a corresponding coating; substantially the entire outer surface 241a is provided with a corresponding coating; and substantially the entire outer surface 241b is provided with a corresponding coating.

[0071] In addition to the outer surfaces 241a, 241b, other areas of the outer surface of the metal body 2 may also be optionally provided with a coating. For example, all or substantially all of the outer surface of the metal body 2 may be provided with a coating.

[0072] The at least one electric heater 3 is in particular located outside the channel 4 , in particular completely outside the channel 4 .

[0073] In particular, the metal body 2 is provided with two passages or holes, in particular through holes. One of the two holes forms the conduit 4 for the liquid. In the other hole 30 ( Figure 3 ) in which the electric heater 3 is arranged or manufactured.

[0074] Each hole is defined by a respective inner surface 21 , 22 of the metal body 2 .

[0075] The metal body 2 is preferably in one piece, in particular obtained by extrusion.

[0076] In particular, the integral metal body 2 comprises the two end portions 24a, 24b. Therefore, the end portions 24a, 24b are also made of aluminum or an aluminum alloy.

[0077] The end portions 24a, 24b are specifically tubular portions.

[0078] A portion of the inner surface 21 of the conduit 4 is formed or defined by the end 24 a , and a portion of the inner surface 21 of the conduit 4 is formed or defined by the end 24 b .

[0079] An outer surface 241 a of the end portion 24 a and an outer surface 241 b of the end portion 24 b are opposed to corresponding portions of the inner surface 21 .

[0080] End 24a includes an opening 242a or inlet portion (for liquid) of conduit 4, and end 24b includes an opening 242b or outlet portion (for liquid) of conduit 4.

[0081] Preferably, the coated end 24a extends from the end defining the inlet 242a (in particular along the longitudinal axis of the conduit 4) by 2 to 150 mm, preferably 10 to 150 mm, preferably 25 to 50 mm; and the coated end 24b extends from the end defining the outlet opening 242b (in particular along the longitudinal axis of the conduit 4) by 2 to 150 mm, preferably 10 to 150 mm, preferably 25 to 50 mm.

[0082] In particular, the inner surface 21 and the inner surface 22 extend around a respective axis, in particular, they extend around a respective longitudinal axis. In particular, the inner surface 21 and the inner surface 22 are continuous surfaces extending around the respective axis. In particular, the respective axis may be straight, curved, or may include one or more straight extensions and one or more curved extensions.

[0083] Preferably, the axes about which the inner surface 21 and the inner surface 22 extend are parallel to each other.

[0084] In particular, it is preferred that the at least one electric heater 3 and the conduit 4 extend parallel to each other.

[0085] Preferably, the length of the inner surface 21 extending around the axis is greater than the length of the inner surface 22 extending around the axis.

[0086] Preferably, the length of the conduit 4 is greater than the length of the at least one electric heater 3 .

[0087] In particular, each end portion 24a, 24b protrudes, in particular outwardly, relative to an end portion 30a, 30b of at least one electric heater 3 adjacent thereto.

[0088] Thus, advantageously, the ends 24a, 24b can be inserted into a respective tube 9, in particular a respective flexible tube.

[0089] However, it is possible that the ends 24a, 24b may be inserted into the respective tube 9 in another way.

[0090] Preferably, the electric heater 3 and the conduit 4 each comprise a helically wound extension. In particular, the helically wound extension of the conduit 4 is arranged between an initial extension of the conduit 4 defined by the end 24a and a final extension of the conduit 5 defined by the end 24b.

[0091] Preferably, the inner surface 21 and the inner surface 22 have a circular cross-section.

[0092] Preferably, the inner diameter of the catheter 4 is 2 to 10 mm, preferably 4 to 7 mm.

[0093] Preferably, end 24a and end 24b are straight or substantially straight.

[0094] The above-mentioned electric heater 3 comprises at least one resistor 31 or resistive element or resistor embedded in an electrically insulating material 32 .

[0095] The resistor 31 is, for example, a resistive cable or wire, preferably helically wound, in particular around its longitudinal axis.

[0096] The electrically insulating material 32 is preferably magnesium oxide.

[0097] The electrically insulating material 32 is in contact, in particular in direct contact, with the inner surface 22 (different from the inner surface 21 ) of the metal body 2 .

[0098] The electric heater 3 is adapted to generate heat by the Joule effect, ie to generate heat when an electric current passes through it.

[0099] Advantageously, the coating coating the inner surface 21 is suitable for ensuring electrical insulation between the electric heater 3 and the edible liquid flowing in the duct 4 , in particular additional electrical insulation relative to said electrically insulating material 32 .

[0100] For power supply, two pins 33a, 33b are provided, each pin being connected to a respective end of the resistor 31. The pins 33a, 33b extend from the metal body 2.

[0101] In particular, two closing elements 34a, 34b made of an electrically insulating material (e.g., a ceramic material) are also provided. The closing elements 34a, 34b are fixed to the metal body 2 and are passed through by corresponding pins 33a, 33b. In particular, the closing elements 34a, 34b are inserted into the hole 30 of the metal body 2 defined by the inner surface 22.

[0102] In all embodiments, the electric heater 3 can transfer heat to the liquid flowing in the conduit 4 through the metal body 2 .

[0103] In particular, the heat generated by the electric heater 3 is transferred to the metal body 2, which in turn transfers the heat to the liquid.

[0104] More specifically, the two holes 4, 30 of the metal body 2 are separated from each other by a wall 23 on the metal body 2. Preferably, a portion of the inner surface 21 and a portion of the inner surface 22 are opposite to each other, and are specifically a portion of the wall 23.

[0105] Optionally, the metal body 2 may also be provided with one or more additional electric heaters 3, each of which is arranged in a corresponding hole of the metal body 2. Therefore, the metal body 2 may be provided with more than two different holes or channels.

[0106] As already mentioned, the invention also relates to a machine for preparing beverages comprising the device 1 .

[0107] In particular, the machine may comprise two tubes 9, in particular two flexible tubes. Figure 1A One of the two tubes 9 is schematically shown in FIG.

[0108] The first of the two tubes 9 is adapted to conduct the liquid to be heated into the conduit 4 , whereas the other of the two tubes (or the second tube) is adapted to receive the heated liquid flowing out of the conduit 4 .

[0109] Specifically, the first end portion 24 a of the metal body 2 is inserted into the first tube 9 , and the second end portion 24 b of the metal body 2 is inserted into the second tube.

[0110] Fixing means 91 are preferably provided for fixing each tube 9, in particular in a sealing manner, to the respective end 24a, 24b.

[0111] By way of example only and not limitation, each tube 9 is secured to a respective end 24a, 24b by one or more clamps 91 .

[0112] The device 1 according to the invention provides several advantages, including those listed below.

[0113] Special References Figure 3 It can be noted that when the ends 24a, 24b are inserted into the respective tubes 9, liquid can enter the gap between each end 24a and 24b and the respective tube into which it is inserted. Advantageously, the coating of the outer surfaces 241a, 241b prevents contact (in particular direct contact) between the liquid and the aluminium or aluminium alloy of which the ends 24a and 24b are made.

[0114] The presence of the coating applied to the inner surface 21 allows the metal body 2 to be made of aluminum or an aluminum alloy so as to transfer heat well and avoids the use of tubes made of, for example, stainless steel in the hole defined by the inner surface 21. In fact, since the coating is suitable for contact with food and is between the liquid and the metal body 2 (the coating is wetted by the liquid), it is not necessary to use steel tubes to overcome the compatibility problems associated with the metal body 2 of aluminum or an aluminum alloy in contact with food. Therefore, the heating device 1 is safe for health.

[0115] The efficiency of the heat exchange between the electric heater 3 and the liquid flowing in the conduit 4 is also improved. In fact, there is no heat loss due to the presence of the steel pipe for the liquid to flow.

[0116] Furthermore, the coating makes it possible to increase the adhesion resistance of the limestone on the wall of the conduit 4 .

[0117] Advantageously, as previously mentioned, by placing a coating between the liquid and the metal body 2, electrical safety is further improved.

[0118] Furthermore, advantageously, by using a coating having a lower electrical conductivity than the material of which the metal body 2 is made, it can be easily and quickly checked whether the coating has been correctly applied, in particular being compatible with large-scale production.

Claims

1. A heating device (1) for a machine for preparing hot beverages, in particular a flow-through heater, The heating device (1) comprises - a metal body (2) made of aluminum or an aluminum alloy; - at least one electric heater (3) arranged in the metal body (2); - a duct (4) for passing an edible liquid to be heated, in particular water, said duct (4) being defined by a first inner surface (21) of said metal body (2); The metal body (2) comprises a first end (24a) and a second end (24b), wherein the first end (24a) and the second end (24b) respectively define an initial extension portion and a final extension portion of the conduit (4); wherein the first end portion (24a) and the second end portion (24b) have corresponding outer surfaces (241a, 241b) and are suitable for being inserted into corresponding tubes (9); The first inner surface (21), the outer surface (241a) of the first end (24a) and the outer surface (241b) of the second end (24b) are coated with corresponding coatings, which are particularly suitable for contacting food.

2. The heating device (1) according to claim 1, wherein: Each coating is made of a polymer material or a sol-gel.

3. The heating device (1) according to claim 1 or 2, wherein: Each coating is made of or substantially made of one of the following materials: polyamide (PA), polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), polyurethane (PU), polyester, epoxy resin material, silicone or sol-gel.

4. The heating device (1) according to claim 1 or 2, wherein: Each coating is made of or consists essentially of one of the following materials: amorphous silicon, amorphous silicon oxide, silicon nitride, silicon dioxide, polycrystalline silicon, fluorocarbon, or organic fluorine.

5. The heating device (1) according to any one of the preceding claims, wherein: Each coating consists of polyamide (PA) or consists essentially of polyamide (PA).

6. The heating device (1) according to any one of the preceding claims, wherein: The thickness of each coating layer is 2 to 100 μm, preferably 5 to 25 μm.

7. The heating device (1) according to any one of the preceding claims, wherein: The length of the conduit (4) is greater than the length of the at least one electric heater (3), in particular such that the first end (24a) and the second end (24b) are suitable for being inserted into the corresponding tube (9).

8. The heating device (1) according to any one of the preceding claims, wherein: Each end (24a, 24b) protrudes relative to an end (30a, 30b) of the at least one electric heater (3) adjacent thereto, in particular protrudes outward.

9. The heating device (1) according to any one of the preceding claims, wherein: The at least one electric heater (3) comprises at least one resistor (31) contained in an electrically insulating material (32), wherein the electrically insulating material (32) is in contact, in particular in direct contact, with the second inner surface (22) of the metal body (2).

10. The heating device (1) according to any one of the preceding claims, wherein: The at least one electric heater (3) and the conduit (4) extend parallel to each other.

11. The heating device (1) according to any one of the preceding claims, wherein: The inner diameter of the catheter (4) is 2 to 10 mm, preferably 4 to 7 mm.

12. A machine for preparing beverages comprising a device (1) according to any one of the preceding claims.

13. Machine according to claim 12, comprising a first tube (9), in particular flexible, and a second tube, in particular flexible; in, The first end portion (24a) is inserted into the first tube (9), and the second end portion (24b) is inserted into the second tube.

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