WO2019077574A1

WO2019077574A1 - Beverage vending machine

Info

Publication number: WO2019077574A1
Application number: PCT/IB2018/058151
Authority: WO
Inventors: Alessandro MERATI; Pierangelo VANZULLI
Original assignee: Carimali SpA
Current assignee: Carimali SpA
Priority date: 2017-10-19
Filing date: 2018-10-19
Publication date: 2019-04-25
Anticipated expiration: 2020-04-19
Also published as: EP3698335A1

Abstract

A beverage vending machine (1) comprising a water supply circuit (2) including a water pump (3) and a water heater (5), a sensory system (7) to output electrical signals that allow the temperature and the amount of water delivered by the water supply circuit (2) to be determined, and an electronic control unit (8) electrically connected to the sensory system (7) to receive the electrical signals outputted thereby, and to the water pump (3) and the water heater (5) to supply electrical control signals thereto. The electronic control unit (8) is configured to determine the variation rate of the amount of water supplied by the water supply circuit (2), determine the variation rate of the temperature of the water supplied by the water supply circuit (2), identify the beverage being delivered based on the variation rate of the amount of water supplied by the water supply circuit (2), when a medium to large beverage is determined to be delivered, start a first intervention on the water heater (5) to adjust the thermal power thereof based on the temperature of the water supplied by the water supply circuit (2), and when the delivery of a medium to large beverage and a negative variation rate of the temperature of the water supplied by the water supply circuit (2) are determined to persist for a given period of time, start a second intervention on the water pump (5) to adjust the water flow rate thereof.

Description

BEVERAGE VENDING MACHINE

Cross-Reference to Related Patent Applications

This patent application claims priority from European Patent Application No. 17197402.5 filed on 19.10.2017, and Italian Patent Application No. 102017000137414 filed on 29.11.2017, the entire disclosure of which is incorporated herein by reference.

Technical Field of the Invention

The present invention relates to beverage vending machines, in particular to machines for preparing hot beverages from brewable substances brewed with pressurized hot water, such as coffee-based beverages, e.g., espresso coffee, instant coffee, long or fresh-brew coffee, etc., or tea-based beverages, and in particular to the electronic control of beverage vending machines aimed at optimizing delivery temperature of medium to large beverages. State of the art

As is known, beverage vending machines comprise a water supply circuit to supply hot or cold water to one or more brewing groups to produce brewed beverages from brewable substances that are contained in suitable containers and may be provided in different forms, in particular powder, or powder and grains, as in the case of coffee, or still further leaves, as in the case of tea.

As schematically shown in Figure 1, in which the beverage vending machine is indicated as a whole with the reference numeral 1, the water supply circuit 2 essentially comprises a water pump 3, typically a variable speed pump, having a suction side fluidically connectable, via an appropriate water filter, to a cold water source 4, which may be a water container or mains water, and a delivery side fluidically connectable to an inlet of a water heater 5.

The water heater may be manufactured with different technologies, and in particular it may be either in the form of a heat exchanger, in which water is heated by exchanging heat with another hot fluid, or in the form of an electromagnetic induction heater, or, more commonly, in the form of an electric boiler, which may be either with a single water heating stage, i.e., with a single water tank and a single electric heater, usually in the form of an electrical resistance, arranged in the water tank, or with two water heating stages, i.e., with two water tanks arranged one inside the other and fluidically series connected, and two electric heaters associated with the two water tanks. Depending on the application of the beverage vending machine 1, the water heating stages may be either of a water storage type, in which a given amount of water is contained in a water tank and heated and maintained at a desired temperature, and when the water boiler is required to deliver a certain amount of hot water to prepare a beverage, the withdrawn amount of water is replenished with fresh water and the water in the water tank is then heated and brought back to the desired temperature, or of a continuous flow type, in which water is heated to a desired temperature while it flows through the heating stage and in response to a beverage selection, i.e., only when water is withdrawn to meet a water demand for a beverage preparation.

In single heating stage electric boilers, the single heating stage is typically of the storage type, whereas in dual heating stage electric boilers, both of the water heating stages may be of the storage type, or the first water heating stage, i.e., the upstream one in the direction of the water flow, is of a storage type, whereas the second water heating stage, i.e. the downstream one in the direction of the water flow, is of a continuous water type.

The water supply circuit 2 further comprises an electronic control system 6 essentially comprising a sensory system 7 to measure one or more physical quantities of the water supply circuit 2, and in particular, inter alia, temperature and amount of water delivered by the water supply circuit 2, and to output electrical signals indicative of the measured quantities, and an electronic control unit 8 electrically connected to the sensory system 7, the water heater 5 and the water pump 3 to receive electrical signals from the sensory system 7 and control operation of the water pump 3 and the water heater 5 based on the electrical signals received from the sensory system 7.

To measure temperature and amount of water delivered by the water supply circuit 2, the sensory system 7 may for example comprise one or more temperature sensors 9 associated with the water heater 5 to measure temperature of the water in one or different areas of the water heater 5, and a volumetric flow meter 10, which may be arranged either upstream from or downstream of the water heater 5 to measure the amount, by volume, of water delivered by the water supply circuit 2, and is typically of the turbine type, in which the water is caused to flow through a small hydraulic turbine whose rotation speed is proportional to the water flow rate and is measured by means of a magnet which is inserted in the turbine to be caused to passed in proximity of a suitable magnetic sensor that outputs an electric pulse per revolution of the turbine. EP 1 827 180 A1 discloses a method and an apparatus for on demand heating a liquid for use in the preparation of beverages, where the heating is dynamically variable based on an applicable beverage profile. The apparatus comprises a heating unit, an electronic controller, and detection devices. A water tank feeds the heating unit via a water pump controlled by the electronic controller, which also controls the heating unit. Feedback control loops provide control data to the electronic controller to optimize the liquid temperature for a given type of beverage in accordance with predetermined beverage profiles.

Object and Summary of the Invention

The Applicant has experienced that the prior art beverage vending machines, although satisfactory in many respects, have considerable room for improvement with regard to the control of the operation of the water supply circuit, in particular for the purpose of optimising the delivery temperature of medium to large beverages.

In particular, the Applicant has found that when a medium to large beverage, i.e. a beverage with a water requirement higher than a given threshold, is delivered, the control strategies implemented by the electronic control units of the prior art beverage vending machines may unsatisfactorily maintain the beverage temperature at the desired values.

Typically, in fact, the water boiler has a maximum flow rate, expressible in cc/min, up to which the water boiler is able to maintain its performance, and beyond which it inevitably fails to bring enough heat to the water contained therein, so resulting in the temperature of the delivered beverage falling as the required water flow increases.

The result is that when a medium to large beverage is delivered, often it is necessary to wait for the water to heat prior to the delivery of a new beverage, so resulting in almost continuous pauses in the beverage delivery when medium to large beverages are selected.

A possible solution could be installing more powerful electric heaters or larger water boilers capable of satisfying the requests, but this inevitably results in a power consumption increase and also in more bulky and expensive beverage vending machines.

Therefore, the object of the present invention is to provide a beverage vending machine, which is improved compared to the known ones as regards the optimization of the delivery temperature of medium to large beverages.

According to the present invention, a beverage vending machine and an electronic control unit therefor are provided, as claimed in the appended claims. Brief Description of the Drawings

The attached Figure schematically shows a water supply circuit and a related electronic control system in a beverage vending machine. Detailed Description of Preferred Embodiments of the Invention

The present invention will now be described in detail with reference to the attached figures in order to allow a skilled person to produce it and use it. Persons skilled in the art will be able to implement various modifications to the embodiments described herein and the general principles disclosed herein could be applied to other embodiments and applications without departing from the scope of the present invention, as disclosed in the appended claims. Accordingly, the present invention is not to be limited in scope to the embodiments described and illustrated herein, but is to be accorded with the widest scope consistent with the principles and characteristics disclosed and claimed herein.

According to the present invention, the electronic control unit 8 is programmed to control the water supply circuit 2 to optimize the delivery temperature of medium to large beverages by implementing a control strategy based on the idea of increasing the maximum flow rate of the water heater 5 imposed by physics (cc/min) without changing the components, enhancing them, and taking better advantage of what is already available, synchronizing the processes in the best way.

In particular, the control strategy implemented by the electronic control unit 8 essentially comprises:

determining the variance or variation rate of the amount of water (volumetric flow rate) supplied by the water supply circuit 2 based on the electrical signal supplied by the volumetric flow meter 10,

- determining the variance or variation rate of the temperature of the water supplied by the water supply circuit 2 based on the electrical signal supplied by the temperature sensor 9, identifying the beverage being delivered based on the variation rate of the amount of water supplied by the water supply circuit 2,

when a medium to large beverage, i.e. a beverage whose preparation requires a medium to high amount of water, i.e. water requirements higher than a given threshold, is determined to be delivered, starting a first intervention on the water heater 5 to adjust the thermal power thereof based on the temperature of the water supplied by the water supply circuit 2, when the delivery of a medium to large beverage and a negative variation rate of the temperature of the water supplied by the water supply circuit 2 are determined to persist for a given period of time, starting a second intervention on the water pump 5 to adjust the water flow rate thereof, and

- carrying out the first and second interventions until when the conditions that caused execution thereof persist, and a beverage is being delivered, and then stopping the execution thereof when the conditions that caused the start thereof cease to exist, or the delivery of the beverage is ended.

The variance or variation rate of the quantity of water supplied by the water supply circuit 2 is determined by first determining the amount of water supplied by the water supply circuit 2 from the moment in time in which the delivery of water has started for the preparation of a selected beverage based on the electrical signal supplied by the volumetric flow meter 10, and then determining the variation rate of the amount of water supplied by the water supply circuit 2, which represents the volumetric flow rate of the water delivered, as the difference between the amounts of water delivered, determined in two successive moments in time, in relation to the time interval in which this difference occurred.

Similarly, the variance or variation rate of the temperature of the water supplied by the water supply circuit 2 is determined by first determining the temperature of the water supplied by the water supply circuit 2 based on the electrical signal supplied by the temperature sensor 9, and then determining the variance or variation rate of the temperature of the water supplied by the water supply circuit 2 as the difference between the temperatures of the water delivered, determined in two successive moments in time, in relation to the time interval in which this difference occurred.

The beverage being delivered is identified based on the variation rate of the water supplied by the water supply circuit 2, and in particular by comparing the variation rate of the water supplied by the water supply circuit 2 with one or more thresholds, and then determining the delivery of a medium to large beverage when the variation rate of the water supplied by the water supply circuit 2 satisfies a predetermined relationship with the threshold value(s), e.g., when the variation rate is higher than a given threshold.

This mechanism allows so-called long or short beverages to be discriminated, distinguishing them based on the low or high water requirements thereof and independently of the recipe or of the predetermination of the type of beverage that will be delivered. In fact, even though the type of beverage and the water requirements thereof are predictable, the recipes are often composite, with several steps, and have behaviours that consume a lot of water, but with low flow rates that can be fully managed by normal operating logics.

The first intervention on the water heater 5 essentially comprises carrying out a first feedback control of the water temperature (controlled quantity) in the water heater 5 by controlling a control quantity (actuator) represented by the thermal power of the water heater 5.

In particular, the first feedback control is designed to cause the thermal power of the water heater 5 to increase to cause the temperature of the water in the water heater 5 either to assume a target value or to follow a target profile.

The first feedback control may be designed to perform an on/off control or a proportional control.

When the water heater 5 is in the form of an electric boiler, the on/off control comprises only switching on and off all the electric heaters in the electric boiler, whereas the proportional control comprises selectively switching on and off the electric heaters in the electric boiler and possibly also adjusting the electrical power absorbed by each of the electric heaters.

The second intervention on the water pump 3 comprises carrying out a second feedback control of the water temperature (controlled quantity) in the water heater 5 by controlling a control quantity (actuator) represented by the flow rate of the water pump 3.

In particular, the second feedback control is designed to cause the flow rate of the water pump 3 to decrease to cause the temperature of the water in the water heater 5 either to assume a target value or to follow a target profile.

When the water pump 3 is of a variable speed pump, the second feedback control is designed to cause the rotation speed of the water pump 3 to decrease to cause the flow rate thereof to decrease to such an extent to allow the water temperature in the water heater 5 to catch up.

The second feedback control is designed to cause the rotation speed of the water pump 3 to decrease up to a predetermined lower, non-zero limit, and as long as a change in the above-described conditions is identified, or until the end of the beverage delivery is determined. Then, when the water temperature in the water heater 5 has once again reached the target temperature, and, hence, the variance of the water temperature in the water heater 5 is no longer negative, the rotation speed of the water pump 3 is again increased as long as this condition persists and until complete return to the initial rotation speed of the water pump 3 or at the end of the beverage delivery.

With regard to the period of time during which the delivery of a medium to large beverage and a negative variance of the water temperature in the water heater 5 are determined to persist, this period of lime may be determined empirically for each type of water heater 5 by determining the time (in seconds or tenths of a second) during which the water temperature in the water heater 5 decreases in response to the withdrawal of a number of cc higher than its capacity.

The above description relates the behaviour and the yield of the water boiler and of the water pump, modulating the intervention thereof, whereby allowing three significant results:

- averagely higher mean beverage temperature in the cup, with consequent improvement in product extraction,

reduced waiting times between successive beverage deliveries, since the water temperature in the water heater 5 fails to decrease to such an extent that re-establishment of the target temperature has to be awaited for,

- maintenance of the installed thermal power even in conditions that would require installation of beverage vending machines 1 that are more powerful in terms of thermal power and/or volume of the water heaters, with cost and power savings for the customer, maintenance of the overall dimensions of the beverage vending machine 1.

Claims

1. An electronic control unit (8) for a beverage vending machine (1) comprising a water supply circuit (2) including a water pump (3) and a water heater (5), and a sensory system (7) to output electrical signals that allow quantities indicative of an amount and a temperature of water delivered by the water supply circuit (2) to be determined;

wherein the electronic control unit (8) is configured to be connectable to the sensory system (7) to receive the electrical signals outputted thereby, and to the water pump (3) and the water heater (5) to supply electrical control signals thereto;

characterised in that the electronic control unit (8) is further configured to:

- determine a variation rate of an amount of water supplied by the water supply circuit (2), determine a variation rate of a temperature of the water supplied by the water supply circuit (2),

identify a beverage being delivered based on the variation rate of the amount of water supplied by the water supply circuit (2),

- when a beverage with water requirements higher than a given threshold is determined to be delivered, start a first intervention on the water heater (5) to adjust the thermal power thereof based on the temperature of the water supplied by the water supply circuit (2), when the delivery of a beverage with water requirements higher than a given threshold and a negative variation rate of the temperature of the water supplied by the water supply circuit (2) are determined to persist for a given period of time, start a second intervention on the water pump (5) to adjust water flow rate thereof.

2. The electronic control unit (8) of claim 1, further configured to:

carry out the first and second interventions until when the conditions that caused execution thereof persist, and a beverage is being delivered.

3. The electronic control unit (8) of claim 1 or 2, further configured to identify the beverage being delivered by:

comparing the variation rate of the amount of water supplied by the water supply circuit (2) with one or more thresholds, and

determining that a beverage with water requirements higher than a given threshold is being delivered when the variation rate of the amount of water supplied by the water supply circuit (2) meets a predetermined relationship with the threshold value(s).

4. The electronic control unit (8) of any one of the preceding claims, wherein the first intervention on the water heater (5) comprises carrying out a first feedback control of the water temperature in the water heater (5) by controlling the thermal power of the water heater (5).

5. The electronic control unit (8) of claim 4, wherein the first feedback control of the water temperature in the water heater (5) is designed to cause the thermal power of the water heater (5) to increase to cause the water temperature in the water heater (5) either to assume a target value or to follow a target profile.

6. The electronic control unit (8) of any one of the preceding claims, wherein the second intervention on the water pump (3) comprises carrying out a second feedback control of the water temperature in the water heater (5) by controlling the water flow rate of the water pump (3).

7. The electronic control unit (8) according to claim 6, wherein the second feedback control of the temperature of the water in the water heater (5) is designed to cause the water flow rate of the water pump (3) to decrease to cause the water temperature in the water heater (5) either to assume a target value or to follow a target profile.

8. The electronic control unit (8) of claim 7 for a variable speed water pump (3), wherein the second feedback control of the water temperature in the water heater (5) is designed to cause the rotation speed of the water pump (3) to decrease to cause the water flow rate thereof to decrease.

9. Software loadable in an electronic control unit (8) in a beverage vending machine

(1) , and designed to cause, when run, the electronic control unit (8) to become configured as claimed in any one of the preceding claims.

10. A beverage vending machine (1) comprising:

- a water supply circuit (2) comprising a water pump (3) and a water heater (5), a sensory system (7) configured to output electrical signals that allow quantities indicative of an amount and a temperature of water delivered by the water supply circuit

(2) to be determined; and an electronic control unit (8) connected to the sensory system (7) to receive the electrical signals outputted thereby, and to the water pump (3) and the water heater (5) to supply electrical control signals thereto, and configured as claimed in any one of the preceding claims 1 to 8.