Espresso coffee machine with system for cleaning the coffee dispensing system

An espresso coffee machine is described, said machine comprising a pump (1) for pumping water, a dispensing group (25) configured to cooperate with a portafilter (35), wherein said portafilter (35) is configured to support a filter (40) loaded with coffee powder, a coffee boiler (15) in fluid communication with said dispensing group (25), a water dispensing system (16, 28, 29, 30) for supplying hot water from said coffee boiler (15) to said portafilter; and a system (16, 31, 6, 33, 14) for supplying steam to said dispensing group (25) so as to perform cleaning of at least a part of said water dispensing system (16, 28, 29, 30).

This application is the U.S. national phase of International Application No. PCT/EP2016/074726 filed 14 Oct. 2016, which designated the U.S. and claims priority to IT Patent Application No. 102015000064045 filed 21 Oct. 2015, the entire contents of each of which are hereby incorporated by reference.

BACKGROUND

Field of the Invention

The present invention relates to the sector of beverage dispensing machines, in particular to the sector of espresso coffee machines. Even more particularly, it relates to an espresso coffee machine with a cleaning system for cleaning the coffee dispensing system and the discharging system.

Related Art and Other Considerations

Typically, an espresso coffee machine comprises one or more dispensing groups. The machine is configured to cause pressurized heated water to pass through a puck of coffee powder contained for example in a filter supported by a portafilter. The portafilter is open at the bottom and has a single or double spout from which the beverage flows out. The beverage is collected inside a container, for example a cup.

More precisely, in an espresso coffee machine of the known type, hot water (for example heated in a boiler or the like) reaches a diffuser via a special duct. The diffuser allows the diffusion of the hot water over a so-called screen and consequently allows hot water to flow down through the underlying puck of coffee powder. The flow of hot water through the aforementioned components continues for the entire duration of dispensing of the beverage.

Once dispensing has been terminated, the fluid remaining above the coffee puck and partly that contained inside it, owing to the difference in pressure between the preparation chamber and discharging chamber, reverses its direction and rises back up the system as far as a discharge well.

The screen is substantially in the form of a disk which is suitably perforated so as to allow the uniform flow of hot water towards the coffee puck during dispensing and, at the same time, prevent the particles of coffee powder from rising back up at the end of dispensing owing to the pressure difference.

The Applicant has noted that, during the discharging process, small particles of used coffee rise back up through the holes of the screen into the diffuser and inside the duct as far as the discharge well, causing at least partial blocking of the system and therefore resulting in the need for consequent operations for maintenance of the aforementioned components.

This functional deterioration is accelerated by the hot used coffee which remains inside the aforementioned components during periods of inactivity of the machine.

The Applicant has also noted that, since some of the components present in the discharging system are also components belonging to the dispensing system, the presence of used coffee particles results in a harmful alteration of the organoleptic properties of the espresso coffee which is dispensed.

The Applicant has also noted that the presence of used coffee in the dispensing system may cause, over time, a reduction in the useful area for through-flow of the dispensing water and consequently the creation of preferential flow paths which may result in a reduced use of the coffee puck. In other words, the hot water does not pass uniformly through the coffee puck during dispensing.

The Applicant has also noted that the presence of used coffee in the discharging system in some cases results in a reduction in the discharging efficiency with the consequent presence of liquid above the coffee puck. This is particularly disadvantageous for the user when separating the portafilter from the dispensing group.

Some baristas, before engaging a portafilter for a new dispensing operation, allow a small quantity of hot water to flow out from the screen for a few moments. With this operation the circuit upstream of the screen and the screen itself are rinsed. However, in order to clean the screen properly, the barista must disassemble it, typically by unscrewing a central screw. Once disassembled, the barista cleans the screen using a chemical product and/or mechanical implements (such as a brush). The manufacturers of espresso coffee machines recommend disassembling the screen at least at the end of every working day.

It is clear that disassembling the screen every day and cleaning it is a long and awkward task which is not liked by baristas. Whatever the case, during most of the day, the screen and the rest of the dispensing/discharging system are dirty and accumulate particles of used coffee.

DE-A-102013107077 discloses an arrangement with a hot-drink machine.

BRIEF SUMMARY

The object of the present invention is therefore to provide an espresso coffee machine with a cleaning system for cleaning in a quick and efficient manner the screen and other components of the coffee discharging and dispensing circuit. In this way at least some of the aforementioned drawbacks are eliminated.

The present invention provides accordingly an espresso coffee machine which uses the steam to clean in an effective manner at least part of the coffee dispensing system and at least some components (typically those which are common to said coffee dispensing system) of the discharging circuit. Preferably, the steam used for cleaning is taken from a boiler (or other steam generator) which is already usually present in an espresso coffee machine in order to allow the preparation of other beverages such as cappuccino, frothed milk or the like.

According to a first aspect of the present invention, an espresso coffee machine is provided, said coffee machine comprising:a pump for pumping watera dispensing group configured to cooperate with a portafilter, wherein said portafilter is configured to support a filter loaded with coffee powder,a coffee boiler in fluid communication with said dispensing group,a water dispensing system for supplying hot water from said coffee boiler to said portafilter; anda system for supplying steam to said dispensing group so as to perform cleaning of at least a part of said dispensing system.

The water dispensing system may comprise a screen.

The machine preferably also comprises a steam boiler. The steam supplied to the dispensing group is taken from said steam boiler.

The steam dispensing system preferably comprises a steam valve body with a plurality of ways, wherein one way is in fluid communication with the steam boiler.

The steam dispensing system preferably comprises a group valve body which is mounted on the group and a pipe which connects the group valve body to said steam valve body, so that the cleaning steam may flow from said steam boiler to said dispensing group passing through said steam valve body, said pipe and said group valve body.

Another way of said steam valve body preferably is connected to a discharge pipe for discharging water after dispensing an espresso coffee.

The machine preferably further comprises a sensor configured to detect whether the portafilter is connected to said dispensing group.

The machine preferably further comprises a processor so that supplying of steam to said dispensing group is carried out depending on a signal received from said sensor.

The machine preferably comprises two or more dispensing groups.

According to another aspect the present invention relates to a method for cleaning a water dispensing system of an espresso coffee machine, wherein the machine comprises:a pump for pumping watera dispensing group configured to cooperate with a portafilter, wherein said portafilter is configured to support a filter loaded with coffee powder,a coffee boiler in fluid communication with said dispensing group,a water dispensing system for supplying hot water from said coffee boiler to said portafilter;wherein said method comprises the step of supplying steam to said dispensing group so as to perform cleaning of at least a part of said dispensing system.

The steam supplied to the dispensing group is preferably taken from said steam boiler.

The steam is preferably fed depending on a signal received from a sensor which is configured to detect whether the portafilter is connected to said dispensing group.

DETAILED DESCRIPTION

FIG. 1shows, in schematic form, a known hydraulic circuit of a machine for preparing and dispensing a beverage according to an embodiment of the present invention; The following symbols have been used for illustrative purposes: long dash-short dash lines=cold water; continuous lines=hot water; regular dash lines=steam; long dash-dot-dot lines=discharge water.

The description below, for the sake of convenience, refers in particular to an espresso coffee machine, but the present invention is not limited to such machines and is applicable to machines for dispensing other beverages. For example, instead of coffee powder, barley powder or other cereal powder may be used. Therefore, the expression “espresso coffee machine” must be understood as comprising also machines for preparing other beverages.

FIG. 1shows an espresso coffee machine according to an embodiment of the present invention. It is shown in simplified form. Some components, which are not relevant for the purposes of understanding of the invention, are not shown and/or will not described in detail. However, for better understanding ofFIG. 1, a list of the various components indicated by a reference number is provided hereinbelow:1. Pump2. Electric motor3. Check valve4. Nipple5. Header6. 3-way valve body7. Nipple8. Nipple9. Hot water dispensing valve body10. Hot water wand11. Level indicator12. Safety valve13. Decompression valve14. Steam boiler15. Coffee boiler16. Group valve body17. Pressure gauge18. Faucet19. Decompression valve20. Steam wand21. Well22. Expansion valve23. Nipple

With reference to the diagram shown inFIG. 1, the machine comprises a pump1which receives water. Typically, the pump1receives water which is not heated. Typically the pump1receives cold water from a mains water pipe and conveys said cold water under pressure to the components downstream thereof. The water which is output from the pump1has a temperature of about 20° C. or in any case at room temperature. The temperature of the water which passes through the pump1is typically influenced by the room temperature and in any case by the external temperature.

A header5is preferably provided downstream of the pump1for doubling the flow. Part of the flow is sent to a steam boiler14provided with an associated valve body6and part is fed to a coffee boiler15. The circuit for feeding the coffee boiler15also has, connected thereto, an expansion valve which allows any overpressure to be controlled and allows water to be discharged from the circuit into the discharge well21.

A safety valve12and a decompression valve13directly connected to the well21are preferably connected to the steam boiler14.

Hot water is preferably drawn from the steam boiler14and supplied via the valve body9and the hot water wand10.

The steam is also preferably taken from the steam boiler via the two mirror-symmetrical branches which connect the boiler to the two steam faucets19and the associated steam wands20.

The steam boiler14is configured to feed the steam wand20preferably provided with a decompression valve19.

The coffee boiler15is in fluid communication with one or more dispensing groups25.FIG. 1shows three delivery groups25supplied by the coffee boiler15, but this arrangement is merely a non-limiting example.

Preferably, a valve body16is provided for each group25. The valve body16, in the continuation of the present description and the claims, will also be referred to as “first valve body” or “group valve body”. Preferably, the group valve body16comprises a three-way valve. For example, the group valve body16may comprise a valve of the type 31A31A1V15T3BDV230AY manufactured by ODE s.r.l. Società Unipersonale, Colico, Italy. The operating principle of the group valve body16will be explained more clearly below.

FIGS. 2aand 2bshow in greater detail a portion of the machine according to an embodiment of the present invention. In particular a dispensing group25(also called simply “group”) of the espresso coffee machine according to the invention is shown. In addition to the group25a number of components necessary for functional operation of the present invention are also shown. Other parts of the machine, not necessary for the present invention, are not shown and/or described.

The dispensing group25is in the form of a substantially cylindrical body connected to the coffee boiler15. Preferably, the coffee boiler15is shaped with a neck26. Considering againFIG. 1, the coffee boiler15with three necks26, one for each group25, is shown.

The group valve body16is present in the top part of the dispensing group25. In the bottom part of the dispensing group25there is a seat27configured to receive and fix a portafilter35. For Example, according to an embodiment, the portafilter35is connected to the dispensing group25by means of a bayonet-type connection or the like. Obviously this is only one example of a connection and other systems for connecting together group25and portafilter35are included in the present invention.

The portafilter35has a handle36and a cavity37configured to seat a coffee filter40. The filter40is filled, at least partly, with coffee powder. The coffee powder is generally pressed and forms a so-called coffee puck or plug41. The water, at a predetermined temperature and a predetermined pressure, is forced to pass through the coffee puck41and flows out from a curved spout38(single or double, as shown in the figure) on the bottom of the portafilter35.

The dispensing group25also comprises a duct28, a diffuser29and a so-called screen30. The duct28extends preferably in the direction of the dispensing group25, as shown inFIG. 2a. The diffuser29is connected to a cavity of the group25at the top of which the duct28is also connected. The screen30is in the form of a perforated disk and serves to distribute the water from the diffuser29as uniformly as possible and prevent the coffee powder from rising up at the end of the dispensing as a result of the difference in pressure.

As already mentioned, the group valve body16is mounted on the dispensing group25. Preferably, and as shown inFIG. 2b, and the group valve body16comprises a three-way valve: a first way16ais fluid communication with the duct28, a second way16bis in fluid communication with a pipe31and a third way16cis in fluid communication with the coffee boiler15.

The pipe31connected to the second way of the group valve body16is in turn connected to a second valve body6. Preferably, the second valve body6comprises a three-way valve. For example, the second valve body6may comprise a valve of the type 31A3ACV30-U manufactured by ODE s.r.l. Società Unipersonale, Colico (LC), Italy.

For the sake of easier illustration,FIG. 1shows only one valve body6connected to the group positioned at the left-hand end ofFIG. 1. However, preferably, one valve body6is provided for each group25of the machine.

As clearly shown inFIG. 2b, a first way6a(on the right in the drawing) receives the pipe31connected to the second way of the group valve body16, a second way6b(directed downwards in the drawing) is connected to a discharge pipe32and a third way6c(on the left in the drawing) receives a steam pipe33connected to the steam boiler14.

According to a preferred embodiment, the dispensing group25may also comprise a sensor34for detecting when a portafilter35is present and correctly engaged inside the seat27.

According to a preferred embodiment, a processor50is provided for processing data from the sensor34and/or from the second valve body6(and/or other components of the machine). In addition or as an alternative, the processor50is configured to control the second valve body6so as to open or close either the second way6bor the third way6c. The processor50could comprise a processor (CPU) mounted on an electronic board.

For the purpose of the present invention, the expression “dispensing system” is understood as meaning a plurality of components, downstream of the coffee boiler and upstream of the coffee puck, which are passed through by hot water under pressure during a cycle for dispensing the espresso coffee. For example, according to an embodiment of the present invention, the dispensing system comprises the group valve body16, the duct28, the diffuser29and the screen30. In other embodiments, the dispensing system could comprise (also) other components or two or more components of the dispensing system could be combined to form a single component. For example, screen and diffuser could be in the form of a single component. According to another example, duct and diffuser could be formed as a single component.

For the purpose of the present invention, the expression “discharging system” is understood as meaning a plurality of components, downstream of the coffee puck, which are passed through by the water during a discharging cycle which follows a cycle for dispensing the espresso coffee. For example, according to an embodiment of the present invention, the discharging system comprises the screen30, the diffuser29, the duct28, the group valve body16, the pipe31, the second valve body6and the discharge pipe32. In other embodiments, the discharging system could comprise (also) other components or two or more components of the discharging system could be combined to form a single component. For example, screen and diffuser could be in the form of a single component. According to another example, duct and diffuser could be formed as a single component.

The dispensing system and the discharging system could comprise components which are common to either system. For example, in the embodiment described in detail, the screen30, the diffuser29, the duct28and the group valve body16are common both to the dispensing system and to the discharging system. They are in fact passed through by hot water under pressure during the dispensing step and by discharging water during the discharging step.

The machine according to the present invention is configured to operate in three modes: 1) dispensing of the beverage, 2) discharging of the water from the dispensing circuit, and 3) cleaning of the circuit. Hereinbelow, with reference to the various Figures, the three modes will be described in detail below.

With reference toFIGS. 3aand 3b, the dispensing cycle used to prepare an espresso coffee or a similar beverage will be described.

When a dispensing command is issued, the hot water from the coffee boiler15passes through the third way of the group valve body16, is directed into the first way and then into the duct28, and into the diffuser29as far as the screen30. The screen30distributes uniformly the hot water over the puck41of coffee powder. The hot water then passes through the coffee puck41, passes through the holes40in the filter40and flows out through the spout38of the portafilter35. Flowing of the fluid through the aforementioned components continues for the entire duration of dispensing of the beverage. Usually a container, such as a small cup or the like, is placed underneath the spout38in order to collect the espresso coffee which is dispensed. During the dispensing cycle, the way6cof the valve body6remains closed, while the ways6aand6bare open even though there is no passage of fluids.

With reference toFIGS. 4aand 4b, the cycle for discharging or emptying the system, which is activated at the end of dispensing, will be described.

Dispensing of the coffee may be terminated by means of a manual command or may be controlled by electronic control components (for example the aforementioned processor50). Once dispensing of the coffee has terminated, the fluid left above the coffee puck41and partly the fluid contained inside it, owing to the difference in pressure generated by the coffee puck41, reverses its direction and rises back up the system comprising the screen30, the diffuser29, the duct28, the second way of the first valve body16, the pipe31, the second valve body6, the discharge pipe32and then the discharge well21. In this way the circuit is emptied substantially entirely of the water and returns to the ambient pressure, thus making it possible to remove safely the portafilter35(in order to remove the used coffee, replace it with another puck of coffee powder and prepare another espresso coffee).

Therefore, during the discharging cycle, the ways6aand6bof the valve body6remain open, while the third way6cis closed.

Optionally, before preparing another coffee and before engaging the portafilter35with the dispensing group25, the barista may allow hot water to flow out freely in order to remove other used coffee residues and dirty water.

The third operating mode of the machine according to the invention is shown inFIGS. 5aand 5b. This mode consists of a mode for cleaning at least part of the dispensing system and in particular the screen30. According to one embodiment, this mode is activated by the barista, for example at the end of a dispensing cycle and/or before starting a new dispensing cycle. According to another embodiment, this mode is activated electronically by means of the sensor34and the processor50: when the sensor34detects that the barista has completed a dispensing cycle, that the discharging cycle has also ended and that that barista has removed the portafilter, the cleaning cycle is automatically activated. According to further alternatives, the cleaning cycle could be activated automatically after a predetermined number of dispensing cycles and/or at predetermined times. Also the duration of the cleaning cycle may be decided by the barista or may be fixed. For example, the cleaning cycle programmed (at time intervals or after a certain number of dispensing cycles) may be longer and more thorough than the manual cycle which is managed independently by the barista.

During the cleaning cycle, the second valve body6(also called steam control valve body) opens the third way6cfor connection to the steam boiler14and allows the steam supplied from the steam boiler14and contained inside the steam removal pipe33to pass inside the pipe31which operated as a discharge pipe for the group valve body16during the discharging step.

The steam continues its path along the second way of the group valve body16, into the duct28, inside the diffuser29, onto the screen30and then flows out from the group25. The path of the steam is indicated by means of arrows inFIGS. 5aand 5b. Obviously, preferably the steam must not be hindered by the filter and/or the portafilter. Therefore, the latter must be preferably removed during the cleaning cycle.

Some parameters could be controlled by the user via the aforementioned processor or other electronic control system. For example, the duration of the steam flow could be controlled. In addition and/or alternatively, the frequency of the cleaning cycle could be controlled. In addition and/or alternatively the delay in starting of the third phase of the cycle could be controlled by disengagement of the portafilter.

The expression “control of the frequency of the cycle” is understood as meaning the possibility of choosing after how many dispensing operations to activate the cleaning cycle, but also the possibility of setting a cleaning cycle comprising several consecutive steam and water dispensing operations activated by the user.

As mentioned above, a big advantage of the present invention consists in the fact that the steam used for the cleaning cycle may be taken from the steam source (steam boiler) which is generally already present in an espresso coffee dispensing machine, in particular in machines intended for professional use.

Advantageously, owing to the present invention, a significant functional improvement is obtained. In fact, the passage of the steam through the screen30, the diffuser29, the duct28, the group valve body16and the discharge pipe31of the group valve body16allows the removal of the used coffee particles from inside them. By so doing, it is possible to prevent hot used coffee particles remaining in conditions where no dispensing is performed, reducing significantly the maintenance operations needed to prevent blockage.

The Applicant estimates that, with the machine according to the present invention, the time interval at which maintenance must be carried out could be prolonged about nine times compared to a conventional machine.

Another important advantage obtained with the present invention is that of maintaining the organoleptic properties of the espresso coffee dispensed. In fact, the cleaning cycle, by means of the steam flow, allows the removal of used coffee particles from the group valve body16, from the duct28, from the diffuser29and from the screen30which are passed through by the water from the coffee boiler, also during dispensing. It is thus possible to preserve unchanged the organoleptic properties of the coffee and prevent them from being altered by the particles resulting from discharging during the previous cycles.

Another important advantage obtained by the present invention is that of maintaining the flowrate and direction of the water. In fact, owing to removal of used coffee from the dispensing system it is possible maintain a constant water through-flow area and consequently a constant water flowrate. Moreover, owing to removal of the obstacles along the dispensing path, it is possible to avoid the creation of preferential paths for the fluid, with a consequent lack of uniformity of the water jet on the coffee puck, and a reduction in the efficient use of said jet.

Another important advantage obtained by the present invention is that of preservation of the drying efficiency. Owing to the removal of the used coffee from the discharge circuit, it is possible to keep the liquid removal capacity of the circuit constant. This ensures that there is always a constant amount of residual water at the end of dispensing above the coffee puck, avoiding the increase thereof which occurs in conventional systems and which is directly related to blockage of the discharge system.