RU2784391C1 - Flow electromagnetic-induction fluid heater in a vending machine for preparing beverages - Google Patents

Abstract

FIELD: heaters.

SUBSTANCE: flow-through electromagnetic induction fluid heater (1, 1', 1'') in a beverage vending machine comprises a tubular body (7) delimiting a fluid channel (7a) and having an inlet (8) and an outlet (10) through which the heated fluid flows out of the channel (7a) in use. The heating element (13, 13', 13") is located at least partially inside the channel (7a) in such a way that it is washed by the water flow during use. The electrical winding (11) is wound directly on the outer surface (12) of the tubular body (7). The winding can be electrically energized to generate an electromagnetic inductive field and thereby heat the heating element (13, 13', 13"). The flow-through electromagnetic induction heater (1, 1', 1'') of the fluid further comprises an upstream deflector (25) located inside the channel (7a) downstream of the inlet (8) and upstream of the heating element (13, 13', 13'') relative to the direction of fluid flow from the inlet (8) to the outlet (10).

EFFECT: deflector is shaped to reduce the hydrodynamic resistance to the passage of said fluid between the inlet (8) and the heating element (13, 13', 13'').

13 cl, 7 dwg

Description

Cross-reference to related patents and applications

This patent application claims priority over Italian patent application no. 102019000009381 filed on 06/18/2019.

The technical field to which the invention belongs

The invention generally relates to the field of vending machines for the preparation of beverages and, in particular, to a flow-through electromagnetic induction heater of a fluid medium, in particular water, milk, air, etc., in a vending machine for preparing hot drinks from dehydrated material, for example coffee, tea, hot chocolate, etc.

State of the art

Vending machines are known for preparing beverages, in particular hot beverages from dehydrated materials such as coffee, tea, hot chocolate and the like.

Such vending machines are provided with one or more heaters for heating water, such as boilers or boilers. Known heaters typically comprise a heating element made of a resistive material and capable of heating the water contained within the tank or container of the machine.

More specifically, the heating element is permanently immersed in the water contained in the container; a potential difference is applied to the ends of the heating element. Thus, an electric current is passed through the heater, which, due to the Joule effect, dissipates energy in the form of heat, thereby heating the water due to thermal conductivity.

Thus, it is necessary to maintain the water in the container at the required temperature in order to guarantee a quick dispensing of the beverage.

It follows that if the machine is not used for a long time, a significant amount of energy will be expended to maintain the required temperature of the water inside the container (usually above 85°C).

In addition, the aforementioned heaters are of the storage type, i.e. to the type in which a given volume of water is held in a container and in which the water is heated and maintained at the desired temperature; when a certain amount of hot water needs to be dispensed to prepare the corresponding drink, the hot water drawn from the container is replaced with water at room temperature. Thus, the water in the container needs to be reheated to the required temperature to ensure that the next dispense occurs at the required temperature.

In the latter case, therefore, a waiting period is necessary for reheating the water, the duration of which depends on the amount of hot water dispensed during one or more previous distributions.

In addition to the temperature, an important parameter to be observed is the flow rate of the hot water supplied, which depends primarily on the type of beverage being prepared; for example, in the case of drinks produced using soluble substances, a significant (at least 10 cc / s) flow of hot water is required. When the flow rate of hot water being dispensed is high, there is a rapid drop in the temperature of the water contained in the container, which leads to a long waiting time for the subsequent dispensing or production of a beverage in which the soluble substance may form lumps.

Documents CN-A-107647785 and WO-A-2016016225 describe two examples of instantaneous water heaters for heating water in beverage vending machines.

The problems described above associated with heating water in beverage vending machines arise from the thermal inertia of heating a given mass of water.

To eliminate these technical disadvantages, solutions are known that use the phenomenon of electromagnetic induction to heat water.

In particular, instantaneous water heaters are known which use electromagnetic induction to generate parasitic currents in a channel made of an electrically conductive material, within which the water to be heated flows. Parasitic currents dissipate energy through the Joule effect in the form of heat, thus heating the channel and therefore the water that flows in contact with this channel.

Electromagnetic induction heaters are known to be particularly advantageous because they allow the water to be heated quickly.

Applicant's EP-A-2868242 describes a heater comprising a metal channel wound in the form of a helix and located in the cavity of a coil made of an electrically insulating material, on which an electromagnetic induction winding is wound.

An alternating electric current is applied to the winding, which generates parasitic currents by electromagnetic induction, which, due to the Joule effect, heat the spiral metal channel and, consequently, the water that flows inside it.

The coil is attached to the support structure of the machine, while the metal channel has no mechanical connections to the coil, but is simply supported by a hydraulic circuit to which it is connected with simple plug-in fittings.

In particular, the metal channel and the coil are radially separated by a free space (air gap).

Thus, the maintenance of the heater and, in particular, the replacement of the metal channel becomes easier, more economical and simpler.

Disclosure of invention

While a heater of the type described above is a functionally viable solution for heating water in dehydrated beverage vending machines, the Applicant has been able to verify that known heaters can be improved, in particular with regard to the overall hydrodynamic efficiency of the heater.

It is an object of the present invention to provide a highly reliable and inexpensive flow-through electromagnetic induction fluid heater that satisfies the above stated requirement for known heaters.

According to the invention, this problem is solved by means of a flow-through electromagnetic induction fluid heater and a hot drinks vending machine comprising the flow-through electromagnetic induction fluid heater as claimed in the appended claims.

Brief description of the drawings

In FIG. 1 is a schematic perspective view of a feeding and heating assembly comprising a heater according to a first preferred embodiment of the present invention, parts removed for clarity.

In FIG. 2 is an enlarged axial sectional view of the heater taken along the line II-II of FIG. 1 with parts removed for clarity.

In FIG. 3 shows a cross section of the heater along the line III-III shown in FIG. 2;

In FIG. 4 similar to FIG. 2 is an enlarged view of a corresponding axial section of a heater in a second preferred embodiment of the present invention, with parts removed for clarity.

In FIG. 5 similar to FIG. 3 is a corresponding cross-sectional view of the heater shown in FIG. four.

In FIG. 6 similar to FIG. 2 is an enlarged view of a corresponding axial section of a heater in a third preferred embodiment of the invention, with parts removed for clarity; and

In FIG. 7, similar to FIG. 3 is a corresponding cross-sectional view of the heater shown in FIG. 6.

Implementation of the invention

The present invention is described below with reference to the heating of water, without omitting any generalization, since the invention can also be used to heat other types of fluids used in beverage vending machines, in particular liquid milk or air used to emulsify liquid milk, or other liquids other than water.

In FIG. 1-3 flow electromagnetic induction fluid heater, designed to heat fluid, in particular water, in a vending machine for the preparation of drinks (not shown in the drawings), in particular hot drinks from dehydrated material, such as coffee, tea, hot chocolate and etc., is generally designated by the reference position 1.

In particular, the heater 1 is part of the feeding and heating unit 2 of the aforementioned machine, which includes:

a hydraulic supply circuit 3 (shown schematically in FIG. 1) provided with a container 4 containing water, preferably water at room temperature, and configured to supply water from the container 4 to the heating device 1 via a tube 5; and

- an electrical circuit 6 (schematically shown in Fig. 1), the function of which is explained below.

In particular, the heater 1 is connected to the electrical circuit 6 and is hydraulically connected to the hydraulic circuit 3.

As shown in FIG. 2, the heater 1 comprises a tubular body 7 internally delimiting a water flow channel 7a. The tubular body 7 is thus internally hollow, has a longitudinal axis A, and has an inlet 8 through which the water to be heated, conveyed by the hydraulic circuit 3, is fed in use to the channel 7a and to an outlet 10 through which the heated water flows out in use. from channel 7a.

According to this preferred and non-limiting embodiment, the tubular body 7 is essentially straight and the channel 7a is coaxial with axis A and has a substantially circular cross section.

According to an alternative implementation, which is not shown in the drawings, the tubular body 7 and/or the channel 7a may have a non-rectilinear configuration, for example, include one or more curved sections; in addition, the channel 7a may have a non-circular cross section (eg, elliptical, oval, square, rectangular, polygonal, etc.).

The tubular body 7 is attached to the internal support structure (not shown in the drawings) of the machine in a known manner, which is not described in detail. In particular, the heater 1 comprises an upper shaped end part 14 and a lower shaped end part 15 located on axially opposite sides of the tubular body 7, attached to the tubular body 7 and adapted for connection (in particular, fastening) with the internal support structure of the machine.

More specifically, the shaped part 14 and the shaped part 15 are located coaxially with the axis A, have an essentially domed shape and define the respective axial closing elements of the tubular body 7.

In one embodiment, the fitting 14 and the fitting 15 are releasably connected to the tubular body 7, for example by means of a threaded connection.

As shown in FIG. 1 and 2, the inlet 8 and the outlet 10 are defined by respective hollow projections extending axially from the mold 14 and from the mold 15, respectively. In particular, these protrusions, and hence the inlet 8 and outlet 10, are arranged coaxially to axis A.

In particular, the axial protrusion of the fitting 14 internally defines a channel 17 which fluidly connects the inlet 8 to the channel 7a, thus allowing water to flow into the channel 7a.

Similarly, the axial protrusion of the fitting 15 internally defines a channel 18 which fluidly connects the channel 7a to the outlet 10, thereby allowing water to flow out of the tubular body 7.

In view of the foregoing, the inlet 8 and the outlet 10 are located at respective opposite axial ends of the tubular body 7.

In the example shown, outlet 10 is hydraulically connected to outlet tube 16 (FIG. 1). The outlet tube 16 is configured to direct the heated water from the heating device 1 into a beverage preparation chamber (not shown) where the heated water falls onto the dehydrated material, typically contained in a pre-perforated capsule. The beverage thus obtained is then fed from the beverage preparation chamber to a dispenser (also not shown in the drawings) by which it is dispensed from the machine.

The heater 1 additionally contains a winding 11 formed by a plurality of concentric spirals 11a wound directly on the outer surface 12 of the tubular body 7.

In particular, the winding 11 is configured to supply it with an alternating electric current of a predetermined frequency and thus generate an electromagnetic induction field.

In more detail, the electric circuit 6, in use, applies an alternating voltage to the respective ends l1b of the winding 11, thus generating the aforementioned alternating electric current and the aforementioned electromagnetic induction field.

In a preferred embodiment, the tubular body 7 is made from a material having zero magnetic susceptibility.

Thus, the tubular body 7 interacts with the electromagnetic induction field generated by the winding 11 to a minimal extent or hardly interacts with it, thus preventing the field from being disturbed.

The heater 1 further comprises a heating element 13, which is located inside the channel 7a so that in use the flow of water flowing inside said channel 7a washes it, and which can be activated in use by the electromagnetic induction field generated by the winding 11.

In particular, when an alternating electric current is applied to the winding 11, an alternating electromagnetic induction field is generated, the lines of force of which pass inside the channel 7a and, in particular, through the heating element 13. According to Faraday's law, a change in the resulting flow of the electromagnetic induction field generates parasitic currents inside the heating element 13 which heat the heating element 13 by means of the Joule effect.

The heating element 13 is usually made from a ferromagnetic material. Thus, inside the heating element 13, the lines of the electromagnetic induction field run closer together, optimizing the generation of parasitic currents, and do not dissipate inside the tubular body 7.

In use, the water that flows inside the channel 7a flows around the heating element 13 and is thus heated by conduction heat transfer.

As shown in FIG. 2, the heating element 13 is radially separated from the tubular body 7, more precisely from the straight section 19 of the channel 7a, by a gap 20 through which water flows during use.

In particular, the heating element 13 extends in the axial direction inside the channel 7a, essentially from the shaped part 14 to the shaped part 15, without contact with the rectilinear section 19 of the channel 7a. More specifically, the heating element 13 is connected to the tubular body 7 via several connecting sections 23 (FIG. 3).

In accordance with this preferred and non-limiting embodiment, the heating element 13 has a substantially circular cross section and is placed inside the channel 7a concentric with the axis A.

Accordingly, gap 20 has a substantially annular cross section.

In an alternative embodiment, which is not shown in the drawings, the heating element 13 may have a non-circular cross section, such as elliptical, oval, square, rectangular, polygonal, etc.

In the example shown in FIG. 2 and 3, the heating element 13 is, in particular, a single rod element.

As shown in FIG. 1, the supply and heating unit 2 further comprises a temperature sensor 21 configured to measure the temperature of the water at the outlet 10.

In particular, the sensor 21 is located at least partially within the channel 18 of the fitting 15 and is thus configured to measure, with an acceptable degree of accuracy, the temperature of the water at the outlet 10.

Node 2 further comprises a logic block 22 configured to receive temperature values measured by sensor 21.

The logic unit 22 is also configured to control the activation and deactivation of the electrical circuit 6, as well as to control the frequency of oscillation of the AC voltage applied by the electrical circuit 6 to the winding 11.

In use, based on the value of the leaving water temperature measured by the sensor 21, the logic unit 22 regulates the oscillation frequency and thus the electrical power output by the electrical circuit 6. Indeed, it is known that a higher temperature corresponds to a greater electrical power due to more heat, emitted by the heating element 13 due to the Joule effect.

Thus, the logic block 22 controls the change in the leaving water temperature.

In addition, the heater 1 in the preferred embodiment is provided with a deflector device 24 for diverting the flow of water, placed inside the channel 7a and containing:

- an upstream baffle or distribution element 25 connected to the heating element 13, in particular, installed on the first end section of the heating element 13 near the inlet 8, downstream of the inlet 8 and the corresponding channel 17 and upstream of the heating element 13; and

a downstream baffle or distribution element 26 connected to the heating element 13, in particular, mounted on the second end section of the heating element 13 opposite the first end section near the outlet 10, downstream of the heating element 13 and upstream of the outlet 10 and the corresponding channel 18.

In particular, the flow of water to be heated, coming from the tube 5 and flowing into the channel 7a through the hole 8 in use, comes into contact with the upstream baffle 25 before coming into contact with the heating element 13. Next, the flow of heated water comes into contact with the downstream baffle 26 before leaving the channel 7a through the outlet 10.

This reduces the hydrodynamic resistance compared to the case when the heating element is not provided with a deflector. At the same time, the overall pressure drop is reduced.

In a preferred embodiment, the upstream baffle 25 and the downstream baffle 26 are substantially domed in shape to avoid abrupt and sudden deflection of the water flow within the channel 7a and to provide a smooth deflection of the flow.

The upstream baffle 25 and the downstream baffle 26 are conveniently positioned coaxial to axis A and therefore coaxial to inlet 8 and outlet 10. Thus, the water flow is deflected as evenly as possible towards the rectilinear section 19 of channel 7a.

As shown in FIG. 2, the shaped part 14 defines from the inside a shaped section 27 of the channel 7a located downstream of the inlet 8, in particular the channel 17, and upstream of the heating element 13, in particular its straight section 19.

In particular, the shaped portion 27 faces at least partially the upstream baffle 25, in particular its outer surface 25a, and has a profile that follows (or repeats) at least partially said outer surface 25a.

Thus, the flow of water flowing in use inside the shaped section 27 of the channel 7a follows a curved and gentle path, that is, without sharp deviations and sharp bends. This helps to further limit the pressure loss in the channel 7a.

In the same way, the shaped part 15 defines inside the shaped section 28 of the channel 7a, located downstream of the heating element 13, in particular its straight section 19, and upstream of the outlet 10, in particular the channel 18.

In particular, the shaped portion 28 faces at least partially the downstream baffle 26, in particular its outer surface 26a, and has a profile that follows (or repeats) at least partially this outer surface 26a. Thus, the flow of water flowing in use inside the shaped section 28 of the channel 7a follows a curved and gentle path, ie without sharp deviations and sharp bends. This contributes to further limiting the pressure drop in the channel 7a.

In addition, as shown in particular in FIG. 2 and 3, the tubular body 7 comprises first supply channels 29, in the specific example four supply channels 29 located downstream of the upstream baffle 25, fluidly connecting the shaped section 27 to the straight section 19 and designed to uniformly distribute the water flow. around the heating element 13. Thus, it is possible to ensure the uniformity of the flow of water, preventing the formation of areas in which water can stagnate, and thus avoid uneven heating of it.

According to this second preferred and non-limiting embodiment, the supply channels 29 are distributed axially symmetrically about axis A, i.e. evenly distributed angularly around said axis A.

The tubular body 7 further comprises second supply channels 30, in a specific example, four supply channels 30 located upstream of the downstream deflector 26, fluidly connecting the straight section 19 to the shaped section 28 and capable of uniformly distributing the flow of water around the downstream deflector 26. deflector flow 26.

The latter contributes to a further reduction in the total hydrodynamic resistance of the heating device 1.

The operation of the inventive heater 1 will be described below with particular reference to the initial state in which the water inside the container 4 is at room temperature.

In this state, when the user orders the dispensing of a drink, the logic unit 22 allows, by means of a system of valves and pumps of a known type (shown schematically in Fig. 1), the flow of water to be heated to pass through the inlet 8 and the channel 17 inside the tubular body 7.

Simultaneously, the logic unit 22 controls the switching on of the electric circuit 6, which applies an alternating voltage of a predetermined frequency to the ends 11b of the winding 11, thus generating an alternating electric current, which in turn generates the aforementioned electromagnetic induction field.

As described above, said field causes heating of the heating element 13, which heats the water flowing through the channel 7a and surrounding said heating element 13.

When heated water flows through channel 18, the sensor 21 measures its temperature and sends the measured value to the logic unit 22. In this way, a closed loop control of the measured temperature is provided.

Then the heated water is fed through the tube 16 into the chamber for preparing the selected drink.

In FIG. 4 and 5, a flow heater implemented in accordance with an alternative preferred embodiment of the present invention is generally indicated by the reference numeral 1'.

Since the heater 1' is similar in design and operation to the heater 1, only its structural and functional differences from the latter are described below.

Similar reference numerals are used to refer to like or equivalent parts and/or functions.

In particular, the heater 1' differs from the heater 1 in that it is provided with a heating element 13', which is, for example, several rod elements.

More precisely, the heating element 13' consists of a bundle of rod elements having a smaller diameter than the diameter of a single rod element forming the heating element 13 of the heating device 1.

In more detail, each of the rod elements of the heating element 13' extends axially inside the channel 7a from the molding 14 to the molding 15.

In more detail, the rod elements are attached to said fittings 14 and 15 with their respective opposite axial end portions.

In use, the flow of water flowing inside the channel 7a washes each of the rod elements, passing in the spaces of the channel 7a between the rod elements. As a result, heat transfer is improved because the total transfer surface of the heating element 13' is larger than that of the heating element 13.

In FIG. 6 and 7, a flow heater implemented in accordance with a further preferred embodiment of the present invention is generally indicated by the reference numeral 1''.

Since the heater 1'' is similar in design and operation to the heater 1, only its structural and functional differences are described below.

Similar reference numerals are used to refer to like or equivalent parts and/or functions.

In particular, the heater 1'' differs from the heater 1 in that it is provided with a heating element 13'', which is, for example, several thin-walled sheets.

In particular, each of the sheets of the heating element 13'' extends axially inside the channel 7a from the mold 14 to the mold 15.

More specifically, the sheets are attached to said fittings 14 and 15 with their respective opposite axial end portions.

In use, the flow of water flowing through the channel 7a washes each of the thin-walled sheets, passing through the spaces defined by each pair of sheets. As a result, heat transfer is improved because the total transmission surface of the heating element 13'' is even larger than that of the heating element 13'.

From a consideration of the features of the heaters 1, 1', 1'' implemented in accordance with the present invention, the advantages achieved with their help become apparent.

In particular, due to the presence of upstream and downstream baffles 25 and 26, the total hydrodynamic resistance of the heaters 1, 1', 1'' is reduced compared to the case when these heaters are not provided with baffles. At the same time, there is a decrease in the overall pressure drop.

Moreover, due to the special shape of the baffles 25 and 26 located upstream and downstream and the shaped sections 27 and 28, a homogeneous and uniform heating of the water stream can be achieved.

Obviously, the described and illustrated heaters 1, 1', 1'' can be modified and changed without going beyond the protection scope of the invention, defined by the attached claims.

In particular, the upstream and downstream baffles 25 and 26 may be integral parts of the heating element 13, 13', 13'' and thus formed respectively by the first and second end portions of the heating element 13, 13', 13' '.

Claims (23)

1. A flow electromagnetic induction heater (1, 1', 1'') of a fluid in a vending machine for preparing drinks, including: - at least one tubular body (7) defining at least one fluid channel (7a) and having at least one inlet (8) through which the fluid to be heated is fed into said channel (7a) during use ), and one outlet (10) through which the heated fluid flows out of said channel (7a) in use; - a heating element (13, 13', 13'') positioned at least partly inside said channel (7a) in such a way that it is bathed in fluid during use; and - an electrical winding (11) wound directly on the outer surface (12) of the tubular body (7), which can be supplied with electrical power to generate an electromagnetic induction field and thus heat the heating element (13, 13', 13'') due to the impact said electromagnetic induction field; wherein the flow-through electromagnetic induction fluid heater (1, 1', 1'') additionally comprises a deflector (25) located upstream, placed inside said channel (7a) downstream of said inlet (8) and upstream of said heating element (13, 13', 13'') with respect to the direction of fluid flow from said inlet (8) to said outlet (10) and having a shape that allows to reduce the hydrodynamic resistance to said fluid flow between said inlet ( 8) and said heating element (13, 13', 13''). 2. Heater (1, 1', 1'') according to claim 1, wherein said upstream baffle (25) is connected to or integral part of said heating element (13, 13', 13''). 3. The heater (1, 1', 1'') according to claim 2, wherein said upstream baffle (25) is mounted on or defined by a first end portion of said heating element (13, 13', 13") located next to said inlet (8). 4. The heater (1, 1', 1'') according to claim 3, in which the said tubular body (7) contains the first shaped part (14) defining from the inside the first shaped section (27) of the mentioned channel (7a), located below downstream of the inlet (8) and upstream of said heating element (13, 13', 13'') and facing the downstream baffle (25); said first shaped section (27) has a profile that follows at least partially the outer surface (25a) of said upstream deflector (25). 5. The heater (1, 1', 1'') according to claim 4, wherein said tubular body (7) further comprises supply channels (29) located downstream of said upstream deflector (25) hydraulically connecting said first shaped section (27) with the rest of said channel (7a) located downstream of said first shaped section (27) and configured to distribute said fluid flow around said heating element (13, 13', 13'') . 6. Heater (1, 1', 1'') according to any of the preceding claims, further comprising a downstream baffle (26) placed in said channel (7a) downstream of said heating element (13, 13', 13 '') and upstream of said outlet (10) with respect to the direction of fluid flow from said inlet (8) to said outlet (10), and shaped to reduce hydrodynamic resistance to fluid flow between said heating element (13, 13', 13'') and said outlet (10). 7. Heater (1, 1', 1'') according to claim 6, wherein said downstream baffle (26) is connected to or integral part of said heating element (13, 13', 13''). 8. Heater (1, 1', 1'') according to claim 7, wherein said downstream baffle (26) is mounted on or defined by a second end portion of said heating element (13, 13', 13''), opposite to said first end section and adjacent to said outlet (10). 9. Heater (1, 1', 1'') according to any one of paragraphs. 6-8, in which said tubular body (7) contains a second shaped part (15) defining from the inside the second shaped section (28) of said channel (7a) located downstream of the heating element (13, 13', 13'') and upstream of the outlet (10) and facing said downstream baffle (26); wherein said second shaped section (28) has a profile that at least partially repeats the profile of the outer surface (26a) of said downstream outlet baffle (26). 10. Heater (1, 1', 1'') according to claim 1 or 6, in which the tubular body (7) has a longitudinal axis (A); wherein said inlet (8), said outlet (10) and said upstream and downstream baffles (25, 26) are concentric to said axis (A). 11. A heater (1, 1', 1'') according to claim 1 or 6, wherein said upstream and downstream baffles (25, 26) are substantially dome-shaped. 12. A heater (1, 1', 1'') according to any one of the preceding claims, wherein said heating element (13, 13', 13") has one of the following configurations: - a rod element, in particular having a substantially circular cross section; a plurality of bar elements, in particular having corresponding substantially circular cross-sections; and - several thin-walled sheets. 13. A vending machine for making drinks, comprising: - flow electromagnetic induction heater (1, 1', 1'') fluid according to any one of the preceding paragraphs; - a fluid supply circuit (3) fluidly connected to said continuous electromagnetic induction fluid heater (1, 1', 1'') to supply it with fluid; and - a power supply circuit (6) electrically connected to said electrical winding (11) to power it.

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