Beverage vending machine

Abstract

A beverage vending machine (1) comprising: a main water tank (12) having a volume V1; a water heater (3); a water pump (16) for supplying water from the main water tank (12) to the water heater (3); a beverage dispensing unit (4) designed to receive hot water from the water heater (3) to prepare and dispense a beverage; a hydraulic circuit (7) fluidically connecting the main water tank (12), the water pump (16), the water heater (3) and the beverage dispensing unit (4) to each other and comprising a water recirculation branch (11) to recirculate hot water flowing out from the water heater (3) back into the hydraulic circuit (7) and to recirculate this hot water through the water heater (3); a recirculation valve device (28) arranged downstream of an outlet of the water heater (3) to selectively supply hot water to the recirculation branch (11) or to the beverage dispensing unit (4); wherein the water recirculation branch (11) extends between the recirculation valve device (28) and a take-off point (32) of the hydraulic circuit (7) arranged downstream of the main water tank (12) in a direction of water flow along the hydraulic circuit (7) to form a closed water recirculation loop; and the hydraulic circuit (7) further comprises a water recirculation tank (31) having a volume V2 smaller than the volume V1 and arranged downstream of the take-off point (32).

Description

[0001] Cross-citation of relevant patent applications

[0002] This patent application claims priority to European Patent Application No. 24152644.1, filed January 18, 2024, European Patent Application No. 24172966.4, filed April 29, 2024, and Italian Patent Application No. 102025000000810, filed January 17, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to an automatic beverage vending machine. Background Technology

[0004] In beverage vending machines, a straight-through or continuous-flow heater (also known as an instant heater) is used to heat the water to be supplied to the beverage dispensing unit. The instant water heater is part of a hydraulic circuit that typically includes: a water tank supplied with cold water from a water supply network; and a water pump that draws water from the water tank and supplies it to the instant water heater.

[0005] Compared to traditional water storage boilers, the advantages of using instantaneous water heaters are well-known, primarily due to energy savings from not having to maintain a large volume of water, smaller size, and the ability to customize the outlet water temperature on demand depending on the beverage selected.

[0006] While instantaneous water heaters are effective, they still have some operational limitations stemming from the fact that the production of most beverages (especially those made from soluble substances) requires instantaneous heating of a certain flow rate of water, necessitating significantly greater instantaneous electrical power than is typically used in systems with storage boilers, thus imposing greater limitations on the available electrical power on site. Furthermore, using instantaneous water heaters with very high power outputs leads to difficulties in controlling the distribution temperature and imposes greater constraints on the management of electrical disturbances (flicker).

[0007] To overcome these limitations, it is known to install a hydraulic circuit between the instant water heater and the beverage dispensing unit. This hydraulic circuit has a valve device designed to supply water flowing out of the instant water heater to a water recirculation branch if the water temperature at the outlet of the instant water heater is not at a predetermined temperature. This prevents the water from reaching the beverage dispensing unit and instead returns it to a storage tank, where it mixes with colder water, thereby increasing its temperature. In this way, the water is recirculated through the instant water heater several times until the water temperature at its outlet reaches the predetermined temperature, and hot water can then be supplied to the beverage dispensing unit.

[0008] For example, a hydraulic circuit having a recirculation branch of the above type is known from EP 2642906 B1 and EP 2895039 B1.

[0009] However, the drawback of these loops is that the temperature of the water in the entire volume of the storage tank needs to be raised to reduce the temperature difference between the inlet and outlet of the instantaneous water heater, thus causing energy waste, increased distribution time, and problems associated with increased scale formation inside the storage tank.

[0010] To overcome this drawback, EP 1097663 B1 discloses a water recirculation branch that does not flow into the water tank, but instead flows into the outlet of a hydraulic circuit downstream of the water tank. However, the applicant has found that this solution is hardly effective because the volume of water heated in the water recirculation branch is significantly smaller than the amount of water required to prepare the beverage. Summary of the Invention

[0011] The purpose of this invention is to provide a beverage vending machine that uses an instant hot water heater and overcomes the aforementioned disadvantages.

[0012] According to the present invention, a beverage vending machine as claimed in the appended claims is provided. Attached Figure Description

[0013] Figure 1 A beverage vending machine according to a first embodiment of the present invention is schematically shown; Figure 2 An automatic beverage vending machine according to a second embodiment of the present invention is illustrated schematically; and Figure 3 An automatic beverage vending machine according to a third embodiment of the present invention is illustrated schematically.

[0014] Figure 4 A beverage vending machine according to a fourth embodiment of the present invention is illustrated schematically. Detailed Implementation

[0015] The invention is described in detail with reference to the accompanying drawings to enable those skilled in the art to practice and use it. Possible variations of the embodiments described herein will be immediately apparent to those skilled in the art, and the general principles described herein can be applied to other embodiments and applications without going beyond the scope of protection set forth in the appended claims. Therefore, the invention should not be considered limited to the embodiments described and shown herein, but rather it must be associated with the widest possible scope of protection based on the principles and features described and claimed herein.

[0016] exist Figure 1In the image, reference numeral 1 schematically represents a beverage vending machine.

[0017] The beverage vending machine 1 includes: a water inlet connected to the water supply network via a measuring solenoid valve 2; a water heater 3; and a beverage dispensing unit 4.

[0018] Water heater 3 belongs to the category of direct-flow or continuous-flow heaters, also known as instantaneous heaters, which are heaters without a water tank and are designed to raise the temperature of the water as it flows through the heater itself.

[0019] Water heater 3 can be manufactured according to any of the known types of instantaneous heaters (e.g., induction heaters, thick film heaters, hot block heaters), in which water to be heated flows along a pipe formed in or integrally with a metal block, the metal block being heated by one or more resistors embedded in the metal block.

[0020] In the example shown in this article, the beverage dispensing unit 4 includes a plurality of known beverage dispensing devices designed to dispense the corresponding type of hot beverage (e.g., coffee, hot chocolate, tea, etc.) into the beverage container 6.

[0021] Conveniently, the beverage dispensing device includes: a mixing unit 5a (known per se), each mixing unit being designed to receive water from a water heater 3 to mix the water with the powdered product supplied to the mixing unit 5a and dispense a relatively hot beverage; and a brewing unit 5b (known per se), designed to produce a beverage by brewing a certain amount of powdered or leaf material with pressurized hot water.

[0022] The beverage vending machine 1 also includes a hydraulic circuit 7 having multiple devices and pipes and including: a first circuit section 8 fluidly connecting the solenoid valve 2 to the water heater 3; a second circuit section 9 fluidly connecting the water heater 3 to the beverage dispensing unit 4; a third circuit section 10 connecting the beverage dispensing unit 4 to the beverage container 6; and a fourth circuit section defining a water recirculation branch 11, which has the function of recirculating water once or multiple times through the water heater 3 until the desired water temperature is reached (described in more detail below).

[0023] The first circuit section 8 includes: a water storage tank 12 having a given volume V1; a water supply pipe 13 from a solenoid valve 2; and an overflow pipe 14 extending between the water storage tank 12 and the solenoid valve 2.

[0024] Conveniently, the water tank 12 defines a so-called "air gap" tank of known type, and is commonly used in beverage vending machines, to prevent water supplied to the water heater 3 from flowing back into the water supply network. The "air gap" tank also serves as a water reserve to ensure that, in the event of a sudden interruption of the water supply from the water supply network, the beverage vending machine 1 has the necessary autonomy to complete the beverage production cycle, and, if necessary, to perform other cycles using the water volume V1 in the "air gap" tank.

[0025] In order to maintain a constant water volume V1, the water tank 12 is typically equipped with a water level maintenance device (not shown), such as a float with a microswitch, which is connected to the electronic control unit 15 of the beverage vending machine 1. The electronic control unit is configured to selectively control the operation of the solenoid valve 2 based on the output of the water level maintenance device.

[0026] The first loop section 8 also includes a water supply pump 16 connected to the water storage tank 12 via a suction pipe 17 and to the water heater 3 via a delivery pipe 18. A volumetric flow meter 19 is arranged along the suction pipe 17 to measure the amount of water supplied by the water supply pump 16 to the water heater 3 and thus to the beverage dispensing unit 4.

[0027] The first loop section 8 also includes an overpressure pipe 20 for recirculating water in the suction pipe 17 when the water pressure at the outlet of the water pump 16 is greater than a given threshold.

[0028] The second circuit section 9 (which fluidly connects the water heater 3 to the beverage dispensing unit 4) includes a valve unit 21, which includes a plurality of solenoid valves 22 arranged to selectively receive pressurized hot water from a supply pipe 24 connected to the outlet of the water heater 3, so as to supply the pressurized hot water to the corresponding device 5a or 5b via a corresponding supply pipe 23.

[0029] Preferably, these solenoid valves 22 are arranged adjacent to each other so that the valve unit 21 forms a single compact assembly, wherein the inlets of the solenoid valves 22 are connected parallel to each other to a supply manifold (not shown), which, from a functional point of view, can be regarded as an extension of the supply pipe 24, and the outlets of the solenoid valves 21 are each connected to the respective device 5a or 5b via the respective supply pipe 23.

[0030] Conveniently, valve unit 21 (more precisely, manifold) is also fluidly connected to wastewater collection container 25 via a corresponding discharge pipe 26.

[0031] For further details of this embodiment of valve unit 21, please refer to WO 2018 / 220552 A1 under the name of the applicant.

[0032] The beverage dispensing unit 4 is connected to the third loop section 10 of the beverage container 6. For each device 5a, 5b, a corresponding dispensing tube 27 extends between the beverage container 6 and the device 5a, 5b itself.

[0033] The fourth loop section (i.e., the water recirculation branch 11) extends between the second loop section 9 and the suction pipe 17 to allow water flowing out of the water heater 3 to flow into the third loop section 10 instead of the third loop section 10 when it is supplied to the water recirculation branch 11, but to flow back into the first loop section 8 downstream of the water tank 12.

[0034] The supply of pressurized hot water to the recirculation branch 11 is controlled by the recirculation solenoid valve 28 connected to the electronic control unit 15, so as to selectively form fluid communication between the supply pipe 24 and the recirculation branch 11.

[0035] Preferably, the recirculation solenoid valve 28 is part of the compact valve unit 21 and is arranged in the direction of water flow adjacent to and parallel to the solenoid valve 22 at the end of the manifold. In this embodiment, the solenoid valve 28 is a two-way valve with its inlet in fluid communication with the manifold (i.e., with the supply line 24) and its outlet in fluid communication with the recirculation branch 11.

[0036] The specific compact configuration of the valve unit 21 and the position of the recirculation solenoid valve 28 in the valve unit 21 have the following advantages: when the temperature at the outlet of the water heater 3 does not reach the predetermined value and water recirculation is activated, the entire valve unit 21 is allowed to be heated.

[0037] In practice, when the electronic control unit 15 closes the solenoid valve 22 and opens the recirculation solenoid valve 28 so that the hot water from the water heater 3 does not flow to the beverage dispensing unit 4, but flows to the water recirculation branch 11, the water flows through the entire manifold and reaches the recirculation solenoid valve 28 and flows into the recirculation branch 11, thereby heating the entire manifold and the assembly of the solenoid valve 22.

[0038] In a variant not shown, the recirculation solenoid valve 28 is a three-way valve arranged upstream of the valve unit 21 along the supply pipe 24.

[0039] In order to measure the water temperature, the water heater 3 is equipped with at least one temperature probe 29 (conveniently an NTC thermistor), which is located at the outlet of the water heater 3 and connected to the electronic control unit 15.

[0040] Preferably, the water heater 3 is provided with another temperature sensor 30 (conveniently an NTC thermistor), which is arranged at the water inlet of the water heater 3 and connected to the electronic control unit 15.

[0041] like Figure 1As shown, the hydraulic circuit 7 also includes a second water tank 31, which has a volume V2 smaller than the volume V1 of the storage tank 12 and is located downstream of the storage tank and the emanation point 32, where the recirculation branch 11 terminates and leads to the suction pipe 17. Therefore, the water tank 31 is arranged to include a closed recirculation circuit formed by the recirculation branch 11, the first circuit section 8, and the second circuit section 9, to allow water flowing out of the water heater 3 and not yet reaching the predetermined temperature to be pumped by the water pump 16 to flow through the heater 3 again the required number of times until the predetermined temperature is reached.

[0042] Therefore, water tank 31 is defined as a "flow-through" water tank, which is filled with water flowing in a closed recirculation loop when water recirculation is activated.

[0043] Compared to known solutions, “through-flow” tanks (such as tank 31) with reduced volumes allow for many advantages, where recirculation branches flow into “storage” tanks (such as, for example, tank 12) with significantly larger capacities than tank 31.

[0044] In fact, the reduced volume V2 of the water tank 31 reduces the volume of water required to be heated to achieve the temperature of hot water during recirculation, and this greatly reduces the preheating time required for the water heater 3 to prepare for dispensing, and thus reduces the waiting time for users to prepare beverages.

[0045] In addition, the “through-flow” arrangement of water tank 31 significantly reduces the impact of thermal stratification, which would otherwise occur in a larger water tank and further prolong the water preheating time and make the outlet temperature less accurate.

[0046] Furthermore, considering that the water tank into which the preheated water is supplied is small and adequately thermally insulated, water tank 31 is significantly more advantageous from both a cost-related and heat dissipation perspective than a larger water tank (such as water tank 12), despite its smaller size.

[0047] Preferably, the water tank 31 has a volume V2 that is commensurate with the water requirements for preparing the beverage.

[0048] Conveniently, the volume of V2 is approximately 100 cc, which is three times smaller than the volume of the usual water tank 12, which is approximately 300 cc.

[0049] exist Figure 1 In the illustrated embodiment, the water tank 31 is arranged between the outlet 32 ​​and the water pump 16. Preferably, the water tank 31 is arranged between the outlet 32 ​​and the volumetric flow meter 19.

[0050] According to other embodiments not shown herein, the water tank 31 may be located at any other point in the recirculation loop.

[0051] exist Figure 2 and Figure 3 In the illustrated embodiment, the water tank 31 is integrally formed within the water heater 3. Specifically, in this embodiment, the water heater 3 includes: a tubular insert 33 having a helical crest 34 on its outer surface; and a cylindrical sleeve 35 coaxial with and fitted onto the tubular insert 33 and in contact with the helical crest 34 to define a helical channel 36 for water flow together with the tubular insert 33.

[0052] Sleeve 35 defines a support for the heating element. For convenience, the heating element is of a known thick-film type and will therefore not be described further.

[0053] The tubular insert 33 has an inner cavity closed at one end by a cap 37 and at the opposite end by a transverse wall 38, which is preferably formed as a single piece together with the tubular insert 33. Two holes are formed in the transverse wall, defining an inlet 39 and an outlet 40 of the water heater 3. The transverse wall 38 forms two seats at the outlet 40 and the inlet 39 to respectively accommodate a temperature probe 29 for measuring the temperature of the hot water flowing out of the water heater 3 and a temperature probe 30 for measuring the temperature of the hot water flowing into the water heater 3.

[0054] The inner cavity of the tubular insert 33 defines the water tank 31 and is in fluid communication with the spiral channel 36 in series.

[0055] Specifically, in Figure 2 In the embodiment shown, the tubular insert 34 has a pipe 41 in the transverse wall 38 that forms a fluid communication between the inlet 39 and the water tank 31, and a pipe 42 that forms a fluid communication between the spiral channel 36 and the outlet 40 of the water heater 3.

[0056] At the end opposite to the transverse wall 38, the tubular insert 34 has a through hole 43 that forms fluid communication between the water tank 31 and the spiral channel 36.

[0057] In use, the water flowing into the water heater 3 from the inlet 39 first flows into the water tank 31 through the pipe 41, then flows out of the water tank 31 and into the spiral channel 36 through the hole 43, and finally flows out of the spiral channel 36 through the pipe 42 and out of the water heater 3 through the outlet 40.

[0058] Therefore, in this configuration, the water tank 31 is arranged in series upstream of the water heater 3 along the flow direction of the water supplied by the water pump 16. Thus, in this configuration, the water contained in the water tank 31 is only preheated to a degree that helps reduce the temperature difference to a value compatible with the power available from the thick-film heating element and the desired distribution temperature. This type of configuration focuses on energy efficiency but requires more complex HW and SW control to manage the outlet temperature at low flow rates.

[0059] exist Figure 3 In one embodiment, pipe 41 forms a fluid connection between the inlet 39 of the water heater 3 and the spiral channel 36, and pipe 42 forms a fluid connection between the water tank 31 and the outlet 40 of the water heater 3.

[0060] At the end opposite to the transverse wall 38, the hole 43 forms a fluid connection between the water tank 31 and the spiral channel 36.

[0061] In use, the water flowing into the water heater 3 from the inlet 39 first flows into the spiral channel 36 through the pipe 41, then flows out from the spiral channel 36 and into the water tank 31 through the hole 43, and finally flows into the pipe 42 and out of the water heater 3 through the outlet 40.

[0062] Therefore, in this configuration, the water tank 31 is arranged in series downstream of the water heater 3. Thus, in this configuration, hot water is supplied to the beverage dispensing unit 4 after all the water contained in the water tank 31 has reached the dispensing temperature, thereby improving the accuracy of the outlet temperature at low flow rates or low volumes, but resulting in potentially lower efficiency due to greater dispersion and longer preheating time.

[0063] Figure 2 and Figure 3 The two implementations have significant advantages stemming from the integral formation of the water tank 31 within the water heater 3, which simplifies the hydraulic circuit 7 and reduces its overall size, as well as the structure of the water heater 3 itself and the use of a thick-film heating element. In fact, Figure 2 and 3 The water heater 3 not only benefits from all the typical advantages of thick film elements, such as reduced power element mass and fast response to heating and cooling, but also exceeds the durability limitations of commonly used heating elements connected to water heaters, because the water heater 3 is completely observable.

[0064] Furthermore, the arrangement of the water tank 31 inside the spiral heating channel 36 reduces the dispersion of some of the remaining energy, because the energy is recovered in the water tank 31 located inside the heating element by recirculating the water for a few seconds at the end of the distribution.

[0065] Figure 4An alternative embodiment is shown in which there is no water tank 12 and the pump 16 is directly supplied with water from the water supply network.

[0066] In this embodiment, the water tank 31 is arranged on the delivery side of the water pump 16.

[0067] The beverage vending machine 1 finally includes an anti-scaling device configured to prevent scale formation inside the instant water heater 3 and in other components and pipes forming the hydraulic circuit 7.

[0068] As is known, the harmful effects of scale deposits are particularly severe when using instantaneous water heaters because the high concentrated power and small size of the water channels can quickly reduce the efficiency of the water heater until the water channels are completely blocked and the water heater stops operating.

[0069] The anti-scaling device according to the invention comprises a magnetic anti-scaling device 44 (i.e., a known device), which ionizes water by inducing a magnetic field, thereby preventing calcium carbonate molecules dissolved in the water from agglomerating into crystals and forming scale, but instead keeping them as smaller crystals suspended in the water in the form of aragonite.

[0070] Compared to known types of traditional softener filters, magnetic anti-scaling devices have several advantages: It is economically advantageous because it does not fail with use and therefore does not require regular replacement like traditional filter softeners; Without altering the pH of the water, as is the case with traditional water softener filters where the pH changes when the water hardness is reduced too much; It does not change the taste of the beverage, unlike in the case of a traditional softener filter.

[0071] The magnetic anti-scaling device 44 can be placed at any point in the hydraulic circuit 7, but it is convenient to place it at a point in the closed water recirculation circuit.

[0072] This arrangement helps overcome some application limitations of connecting to magnetic anti-scaling devices, and in fact, "magnetic regulation" typically only works well over a narrow flow rate range and may lose its effectiveness at low flow rates (e.g., the typical flow rate of an espresso beverage). Furthermore, the effect of magnetic regulation diminishes over time, initially when water does not flow through the magnetic filter again (e.g., a beverage vending machine does not dispense a given amount of beverage), allowing calcium carbonate molecules to aggregate and form scale.

[0073] The positioning of the magnetic anti-scaling device 44 within the recirculation loop helps overcome these limitations, which would otherwise arise if the magnetic anti-scaling device 44 were positioned upstream of the solenoid valve 2 that controls the inflow of water into the tank 12. In fact, if the magnetic anti-scaling device 44 is arranged along the recirculation loop, the water is regulated each time a selection is made, not just when the inlet solenoid valve 2 is activated; furthermore, the water is treated at its maximum useful flow rate, and the effect of magnetic regulation is multiplied as the water flows through the magnetic anti-scaling device 44 multiple times.

[0074] Furthermore, positioning the magnetic anti-scaling device 44 in the water recirculation loop allows the water to be periodically processed even during the inactive phase of the beverage vending machine, in order to compensate for the loss of ionization effect over time by periodically reactivating the water recirculation without activating the heating element of the water heater 3.

[0075] Advantageously, the reactivation of the recirculation (without heating) can also be performed at the end of each distribution phase to lower the temperature inside the spiral channel 36 of the water heater 3 due to the redistribution of the remaining hot water throughout the recirculation loop and the water tank 31. Therefore, the reactivation of the recirculation (without heating) at the end of each distribution phase further reduces scale buildup because the lower temperature inside the spiral channel 36 of the water heater 3 prevents scale formation and deposition, and because the reactivation of the recirculation allows water to flow again through the magnetic anti-scaling device 44.

Claims

1. A beverage vending machine (1), comprising: The main water tank (12) has a volume of V1; The water heater (3) is an instantaneous fluid heater; A water pump (16) is used to supply water from the main water tank (12) to the water heater (3). A beverage dispensing unit (4) is used to receive hot water from the water heater (3) and to prepare and dispense beverages; The hydraulic circuit (7) fluidly connects the main water tank (12), the water pump (16), the water heater (3) and the beverage dispensing unit (4) to each other, and the hydraulic circuit includes a water recirculation branch (11) to recirculate the hot water flowing out of the water heater (3) back into the hydraulic circuit (7) and to recirculate the hot water through the water heater (3). A water recirculation valve device (28) is arranged downstream of the outlet of the water heater (3) to selectively supply hot water to the water recirculation branch (11) or the beverage dispensing unit (4). The water recirculation branch (11) extends between the water recirculation valve device (28) and the hydraulic circuit (7) located downstream of the main water tank (12) to form a closed water recirculation circuit. Furthermore, the hydraulic circuit (7) also includes a water recirculation tank (31), the volume V2 of which is smaller than the volume V1, and the water recirculation tank is arranged downstream of the water outlet (32) along the closed water recirculation circuit.

2. A beverage vending machine (1), comprising: Inlet (2); The water heater (3) is an instantaneous fluid heater; A water pump (16) is used to supply water from the inlet (2) to the water heater (3). A beverage dispensing unit (4) is used to receive hot water from the water heater (3) and to prepare and dispense beverages; The hydraulic circuit (7) fluidly connects the water inlet (2), the water pump (16), the water heater (3) and the beverage delivery unit (4) to each other, and the hydraulic circuit includes a water recirculation branch (11) to recirculate the hot water flowing out of the water heater (3) back into the hydraulic circuit (7) and to recirculate the hot water through the water heater (3). A water recirculation valve device (28) is arranged downstream of the outlet of the water heater (3) to selectively supply hot water to the recirculation branch (11) or the beverage distribution unit (4). The water recirculation branch (11) extends between the water recirculation valve device (28) and the water outlet point (32) of the hydraulic circuit (7) to form a closed water recirculation circuit; Furthermore, the hydraulic circuit (7) also includes a water recirculation tank (31) arranged between the water pump (16) and the water outlet (32).

3. The beverage vending machine (1) according to claim 1, wherein the water recirculation tank (31) is arranged along a water suction pipe (17) that connects the main water tank (12) to the suction side of the water pump (16).

4. The beverage vending machine (1) according to any one of the preceding claims, wherein, The hydraulic circuit (7) includes a magnetic anti-scaling device (44) arranged downstream of the water outlet (32) along the closed water recirculation circuit.

5. The beverage vending machine (1) according to any one of the preceding claims, wherein, The water recirculation tank (31) is integrally formed within the water heater (3).

6. The beverage vending machine (1) according to claim 5, wherein, The water heater (3) includes: a tubular insert (33) having a helical ridge (34) on its outer surface; and a cylindrical sleeve (35) coaxial with the tubular insert (33), supporting a heating element and fitted onto the tubular insert (33) and in contact with the helical ridge (34) to define a helical channel (36) for water flow together with the tubular insert (33); wherein the tubular insert (33) is closed at both ends of the tubular insert and defines an inner cavity that defines the water recirculation reservoir (31) and is in fluid communication with the helical channel (36) in series.

7. The beverage vending machine (1) according to claim 6, wherein, The water recirculation tank (31) is in fluid communication with the inlet (39) of the water heater (3), and the spiral channel (36) is in fluid communication with the outlet (40) of the water heater (3); the inlet (39) and the outlet (40) are formed at the same end of the tubular insert (33), and the tubular insert (33) has a through hole (43) at the opposite end of the tubular insert, the through hole connecting the water recirculation tank (31) and the spiral channel (36) in fluid communication, such that the water recirculation tank (31) is arranged in series and is upstream of the spiral channel (36).

8. The beverage vending machine (1) according to claim 6, wherein, The spiral channel (36) is in fluid communication with the inlet (39) of the water heater (3), and the water recirculation tank (31) is in fluid communication with the outlet (40) of the water heater (3); the inlet (39) and the outlet (40) are formed at the same end of the tubular insert (33), and the tubular insert (33) has a through hole (43) at the opposite end of the tubular insert, the through hole connecting the water recirculation reservoir (31) to the spiral channel (36) in a fluid connection, such that the water recirculation reservoir (31) is arranged in series in the direction of water flow along the hydraulic circuit (7) and downstream of the spiral channel (36).

9. The beverage vending machine (1) according to any one of claims 6 to 8, wherein, The heating element is of the thick film type.

10. The beverage vending machine (1) according to any one of the preceding claims, wherein, The water recirculation valve device (28) is part of a compact valve assembly (21), which also includes: a plurality of water distribution valve devices (22) for controlling the flow of hot water to the corresponding beverage preparation devices (5a, 5b); and a water supply manifold designed to receive hot water from the outlet of the water heater (3) and selectively supply hot water to the water recirculation valve device (28) and the water delivery valve device (22); wherein the water recirculation valve device (28) and the water distribution valve device (22) are arranged in parallel with each other relative to the direction of water flow along the hydraulic circuit (7), and the water recirculation valve device (28) is arranged at the end of the water supply manifold such that when hot water is supplied to the water recirculation branch (11), the hot water flows through the water supply manifold and heats the entire compact valve unit (21).

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