RU2783504C9 - Flow electromagnetic induction fluid heater in a beverage vending machine - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of electrical engineering, in particular, to a flow electromagnetic induction fluid heater in a beverage vending machine. The technical result is achieved by the flow electromagnetic induction fluid heater containing a tubular body with a longitudinal axis, wherein at least one fluid channel is formed in said body including at least one inlet whereby the fluid to be heated is supplied into the channel during use and one outlet whereby the heated fluid is discharged from the channel during use; a heating element located at least partially inside the channel so as to be surrounded by the fluid during use; and an electrical winding wound with direct contact around the outer surface of the tubular body, where to electrical power can be supplied in order to create an electromagnetic induction field and thereby heat said heating element due to the effect of said electromagnetic induction field.

EFFECT: reliable operation of the claimed solution.

9 cl, 7 dwg

Description

Cross-reference to related application

This patent application claims the priority of Italian patent application no. 102019000009384 filed on 06/18/2019.

The field of technology to which the invention belongs

The present invention generally relates to the field of beverage vending machines, in particular to a flow-through electromagnetic induction fluid heater for heating a fluid, in particular water, milk, air, etc., in a beverage vending machine to prepare hot drinks from dehydrated material such as coffee, tea, hot chocolate, etc.

State of the art

Beverage vending machines are known, in particular for preparing hot drinks, from dehydrated material such as coffee, tea, hot chocolate and the like.

Such beverage vending machines are provided with one or more heaters capable of heating water, such as boilers or kettles. Known heaters generally 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 constantly immersed in water contained in the container, and a potential difference is applied to the ends of the heating element. Thus, an electric current is generated inside the latter, 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 contained in the container at the desired temperature in order to guarantee a quick dispensing of the beverage.

It follows that if the machine is idle for long periods of time, a significant amount of energy will be consumed to maintain the desired temperature of the water inside the container (typically above 85°C).

Moreover, the heaters mentioned above are of the storage type, that is to say the type in which a predetermined volume of water is held in a container and in which the water is heated and maintained at the desired temperature; when a certain volume of hot water needs to be dispensed to prepare the corresponding drink, the hot water taken from the container is replenished with water at room temperature. Thus, the water in the container must be heated and brought back to the desired temperature to ensure that the next dispense occurs at the desired temperature.

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

In addition to temperature, an important parameter to be controlled is the flow rate of hot water supplied, which depends primarily on the type of beverage being prepared; for example, in the case of beverages produced using soluble substances, a significant (at least 10 cm ³ /s) consumption of hot water is required. If the hot water supply is high, there will be a rapid drop in the temperature of the water contained in the container, resulting in a long waiting time for subsequent dispensing or a beverage in which the solute may form lumps.

Documents FR-A-2855359, EP-A-1380243 and DE-A-102007034370 give examples of instantaneous water heaters for heating water using heat generated by electrical resistances.

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

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 create parasitic currents in a channel made of electrically conductive material, within which the water to be heated flows. Parasitic currents dissipate energy through the Joule effect in the form of heat, thereby heating the channel and therefore the water that flows in contact with it.

As is known, electromagnetic induction heaters are particularly advantageous, as 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 which is made of an electrically insulating material and which is wound with a winding to produce electromagnetic induction.

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

The coil is attached to the support structure of the machine, while the metal conduit has no mechanical connection to the coil, but is simply supported by a hydraulic circuit to which it is attached with simple quick-release (plug-in) fittings.

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

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

JP-A-2001284034 describes an example of an instantaneous water heater that provides heating by electromagnetic induction.

Disclosure of the essence of the invention

While a heater of the type described above is a functionally viable solution for heating water in beverage vending machines, the Applicant has been able to see that known heaters can be further improved, in particular with regard to the heat exchange efficiency achieved by the heater.

The object of the present invention is to provide a flow-through electromagnetic induction fluid heater which is very reliable and has a limited cost and which satisfies the requirements mentioned above in connection with known heaters.

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

Brief description of the drawings

In FIG. 1 is a schematic perspective view, with details removed for clarity, of a supply and heating unit comprising a heater according to a first preferred embodiment of the present invention;

in fig. 2 - on an enlarged scale and with details removed for clarity, axial section along the line II-II, indicated in Fig.1;

in fig. 3 - cross section along the line III-III, indicated in Fig.2;

in fig. 4 - as in Fig. 2 is a corresponding axial section, on an enlarged scale and with details removed for clarity, of a heater in accordance with a second preferred embodiment of the invention;

in fig. 5 - as in Fig. 3 is a corresponding cross section of the heater shown in FIG. four;

in fig. 6 - as in Fig. 2 is a corresponding axial section, on an enlarged scale and with details removed for clarity, of a heater in accordance with a third preferred embodiment of the invention; and

in fig. 7 - as in Fig. 3, a corresponding cross section of the heater shown in FIG. 6.

Implementation of the invention

The present invention will be described below with reference to the heating of water, without derogating from any generality in this regard, since it can also be used to heat other types of fluids used in beverage vending machines, in particular liquid milk or air used for emulsifying liquid milk, or other fluids other than water.

In FIG. 1-3 show a flow-through electromagnetic induction fluid heater for heating fluid, in particular water, in a beverage vending machine (not shown), in particular for preparing hot drinks from dehydrated material such as coffee, tea, hot chocolate, etc. n., which is generally indicated by position 1.

In particular, the heater 1 is part of the supply and heating unit 2 of the aforementioned beverage vending machine, which comprises:

- a hydraulic supply circuit 3 (which is shown schematically in Fig. 1) provided with a tank 4 containing water, preferably water at room temperature, and configured to direct the flow of water from the tank 4 to the heating device 1 through a pipe 5; and

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

In particular, the heater 1 is connected to the electrical circuit 6 and is in fluid communication with the hydraulic circuit 3.

As shown in FIG. 2, the heater 1 comprises a tubular body 7 within which a water flow channel 7a is formed. Thus, the tubular body 7 is hollow, has a longitudinal axis A, and comprises an inlet 8 through which the water to be heated and transported by the hydraulic circuit 3 is fed into the channel 7a in use, and an outlet 10 through which the heated water is in use flows out of channel 7a.

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

According to a non-shown alternative embodiment of the invention, the tubular body 7 and/or the channel 7a may have a non-rectilinear configuration, for example, including one or more curved sections; moreover, 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) of the machine in a known manner, which is not described in detail.

In particular, the heater 1 comprises an upper end portion 14 and a lower end portion 15, which are placed axially on opposite sides of the tubular body 7, are attached to the tubular body 7 and are capable of being attached (in particular, mounted) to the internal support structure of the machine.

More specifically, the upper end portion 14 and the lower end portion 15 form respective axial closing members of the tubular body 7.

In one embodiment of the invention, the upper end portion 14 and the lower end portion 15 are connected to the tubular body 7 in a removable manner, for example by means of a threaded connection.

As shown in FIG. 1 and 2, the inlet 8 and the outlet 10 are formed by respective protrusions extending in the axial direction from the upper end portion 14 and from the lower end portion 15, respectively.

More specifically, a channel 17 is formed within the upper end portion 14, which fluidly connects the inlet 8 to the channel 7a, thereby allowing water to pass through the upper end portion 14 and flow into the channel 7a.

Likewise, a channel 18 is formed within the lower end portion 15 which fluidly connects the channel 7a to the outlet 10, thereby allowing water to pass through the lower end portion 15 and flow out of the tubular body 7.

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

In the example shown, outlet 10 is fluidly connected to outlet pipe 16 (FIG. 1). This outlet pipe 16 is configured to supply heated water from the heating device 1 to a beverage preparation chamber (not shown) where the heated water surrounds the dehydrated material typically contained in a pre-pierced capsule. The beverage thus obtained is then fed from the beverage preparation chamber to a beverage dispenser (also not shown) by which it is dispensed from the machine.

The heater 1 additionally contains a winding 11 formed by a plurality of concentric turns 11a wound with direct contact on the outer surface 12 of the tubular body 7.

More specifically, the winding 11 is configured to supply an alternating electric current with a predetermined oscillation frequency and thereby create an electromagnetic induction field.

More specifically, in use, the electric circuit 6 applies an alternating voltage to the respective ends 11b of the winding 11, thereby generating the aforementioned alternating electric current and the aforementioned electromagnetic induction field.

Preferably, the tubular body 7 is made of 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 practically does not interact with it, thereby preventing distortion of the latter.

The heater 1 further comprises a heating element 13, which is located inside the channel 7a so that in use it is surrounded by a stream of water flowing inside said channel 7a, and which, in use, can be activated by means of an 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 created, the lines of force of which intersect inside the channel 7a and, in particular, pass through the heating element 13. According to Faraday's law, a change in the resulting flow of the electromagnetic induction field creates parasitic currents inside the heating element. element 13, which heat the heating element 13 due to the Joule effect.

The heating element 13 is preferably made of a ferromagnetic material. Thus, the lines of the electromagnetic induction field are closest inside the heating element 13, optimizing the occurrence of parasitic currents, and do not dissipate inside the tubular body 7.

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

As shown in FIG. 2, the heating element 13 is radially spaced from the tubular body 7, more specifically from the inner surface 19 of the channel 7a, by a gap 20 within which water flows during use.

In particular, the heating element 13 extends axially inside the channel 7a from the upper end portion 14 to the lower end portion 15 without any contact with the inner surface 19 of the channel 7a. More specifically, the heating element 13 is attached to the upper and lower end portions 14 and 15.

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

Accordingly, gap 20 has a substantially annular cross section.

According to an alternative embodiment of the invention, which is not shown, 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 comprises, in particular consists of, a single rod element.

As shown in FIG. 1 and 2, 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 lower end portion 15 of the heater 1 and is thus capable of measuring, to a reasonable approximation, the temperature of the water at the outlet 10.

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

The logic block 22 is also configured to control the activation and deactivation of the electrical circuit 6, as well as to control the frequency of oscillations of the alternating 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 supplied by the electrical circuit 6. Indeed, it is known that a higher temperature corresponds to a greater electrical power and as a result more heat generated by the Joule effect of the heating element 13.

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

The inlet 8 and the outlet 10 of the tubular body 7 are preferably located in respective eccentric positions with respect to axis A.

In particular, the inlet 8 and the outlet 10 are located in respective diametrically opposite positions with respect to axis A.

Thus, in use, water flows within the channel 7a from the inlet 8 to the outlet 10 in accordance with a non-laminar motion. Indeed, since the inlet and outlet openings 8 and 10 are located on diametrically opposite sides with respect to axis A, the water within the gap 20 flows in turbulent motion around the heating element 13 in such a way as to ensure uniform contact of the fluid with said heating element 13.

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

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

Simultaneously, the logic unit 22 controls the activation of the electrical 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 produces the aforementioned electromagnetic inductive field.

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

When the heated water flows through the channel 18, the sensor 21 measures its temperature and sends the measured value to the logic unit 22. Thus, feedback control of the measured temperature is achieved.

Then the heated water is supplied through pipe 16 to 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 1'.

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

The same reference numerals will be used to refer to like or equivalent parts and/or features.

In particular, the heater 1' differs from the heater 1 in that it is provided with a heating element 13', which contains a plurality of rod elements, in particular consists of them.

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

In particular, each of the rod elements of the heating element 13' extends axially inside the channel 7a from the upper end portion 14 to the lower end portion 15.

More specifically, the rod elements are attached to these upper and lower end portions 14 and 15.

In use, the flow of water flowing within the channel 7a surrounds 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 heat exchange 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 another preferred embodiment of the present invention is generally indicated by 1''.

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

The same reference numerals will be used to refer to like or equivalent parts and/or features.

In particular, the heater 1'' differs from the heater 1 in that it is provided with a heating element 13'' which contains, in particular consists of, a plurality of thin sheets.

In particular, each of the sheets of the heating element 13'' extends in the axial direction inside the channel 7a from the upper end portion 14 to the lower end portion 15.

More specifically, sheets are attached to these upper and lower end portions 14 and 15.

In use, the flow of water flowing within the channel 7a surrounds each of the thin sheets, passing through the spaces formed between each pair of sheets. As a result, heat transfer is improved because the total heat exchange surface of the heating element 13'' is much 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, by arranging the inlet and outlet openings 8 and 10, a uniform flow of water can be achieved within the channel 7a of the tubular body 7 in order to obtain a substantially turbulent flow around the heating element 13, 13', 13'' and thus efficient and more efficient. uniform heat exchange with the latter.

Moreover, due to the shape of the heating element 13', an increased heat exchange can be achieved since the heat exchange surface is larger than that of the heating element 13.

In addition, due to the shape of the heating element 13'', this improvement becomes much more noticeable, since the ratio between the heat exchange surface and the volume of the heating element 13'' is larger compared to the ratio between the heat exchange surface and the volume of the heating element 13, 13'.

As a result, it is obvious that the described and shown heaters 1, 1', 1'' can be modified and changed without deviating from the protection scope defined by the claims.

Claims (17)

1. Flow-through electromagnetic induction heater (1, 1', 1'') of fluid for a beverage vending machine, wherein the flow electromagnetic induction heater (1, 1', 1'') fluid contains: - at least one tubular body (7) having a longitudinal axis (A), within which at least one fluid channel (7a) is formed and which includes at least one inlet (8), through which, when in use, the fluid to be heated is supplied to said channel (7a), and one outlet (10) through which, in use, the heated fluid flows out of said channel (7a); - a heating element (13, 13', 13'') located at least partially inside said channel (7a) so that it is surrounded by fluid during use; and - an electrical winding (11) wound with direct contact on the outer surface (12) of said tubular body (7), which can be supplied with electrical power to create an electromagnetic induction field and thus heat the heating element (13, 13', 13'' ) due to the action of the mentioned electromagnetic induction field; wherein said inlet and outlet openings (8, 10) are located at respective opposite axial ends of said tubular body (7) in eccentric positions with respect to said longitudinal axis (A). 2. A heater (1, 1', 1'') according to claim 1, wherein said inlet and outlet openings (8, 10) are located in respective diametrically opposite positions with respect to said axis (A). 3. Heater (1, 1', 1'') according to claim 1 or 2, in which said heating element (13, 13', 13'') is radially spaced from the inner surface (19) of said channel (7a) through a gap (20), inside which fluid flows during use. 4. Heater (1, 1', 1'') according to any one of paragraphs. 1-3, in which said heating element (13, 13', 13'') is aligned with said axis (A). 5. Heater (1, 1', 1'') according to any one of paragraphs. 1-4, in which said tubular body (7) is made of a material having zero magnetic susceptibility. 6. Heater (1, 1', 1'') according to any one of paragraphs. 1-5, in which said channel (7a) has a substantially circular cross section. 7. Heater (1, 1') according to any one of paragraphs. 1-6, in which said heating element (13, 13') comprises one or more rod elements or one or more thin sheets surrounded in use by said fluid. 8. Heater (1, 1', 1'') according to claim 7, in which the rod element has a cross-section having a substantially circular shape. 9. A beverage vending machine, comprising: - flow electromagnetic induction heater (1, 1', 1'') fluid according to any one of paragraphs. 1-8; - a fluid supply circuit (3) connected in fluid medium to said flow-through electromagnetic induction heater (1, 1', 1'') of fluid to supply fluid to it; and - a power supply circuit (6) electrically connected to said electrical winding (11) for its power supply.

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