"COFFEE MAKER WITH A FROTHING DEVICE"

[0001] The object of the present invention is a coffee maker capable of producing a beverage having a particularly dense and compact foam.

[0002] As is well known, the traditional coffee maker, better known as the "moka", produced by the applicant since the beginning of the 20th century, is enormously popular the world over, and even in recent years, despite the growth of alternative systems, such as those using a capsule, nearly 2 million mokas were sold annually.

[0003] The users of the coffee maker are generally fond of the flavor of the beverage obtained with this type of machine, which is very different from that obtained with the aforesaid alternative systems.

[0004] Nevertheless, there is no doubt that users appreciate any device that allows a coffee maker to produce a beverage having a dense and compact foam, as is the case with some alternative systems.

[0005] Evidence of such appreciation are the efforts that coffee maker manufacturers have made and are currently still making to produce coffee makers with more or less complex devices able to obtain a beverage with a dense and compact foam.

[0006] Such efforts are demonstrated by the numerous patent documents that illustrate examples of such devices, such as the documents EP-A1-1813173, W02008/087481, W02016/113621, WO03/056986, WO03/055366, GB2436280.

[0007] However, such devices often fail to guarantee the production of a beverage with a truly dense and compact foam; moreover, they are often particularly complex to manufacture and often unsuitable for large-volume production .

[0008] The purpose of the present invention is to create a coffee maker provided with a device that ensures the production of a beverage with a dense and compact foam, which is both economical and easy to assemble.

[0009] Such object is achieved by a coffee maker according to claim 1. The dependent claims describe further advantageous embodiments.

[0010] The features and advantages of the coffee maker according to the present invention will be apparent from the description given below, provided by way of non limiting example, in accordance with the accompanying figures, wherein:

figure 1 shows a coffee maker according to an embodiment of the present invention;

- figure 2 shows a magnification of an end area of a pipe of a coffee maker in figure 1, provided with a frothing device with pressure valve in the open configuration; - figure 3 shows a magnification of the end area of the pipe of the coffee maker in figure 1, with the frothing device in the closed configuration;

- figure 4 shows a ring of the frothing device;

- figure 5 shows the frothing device in figure 2, in separate parts;

- figure 6 shows a nozzle of the frothing device; and

- figure 7 shows the frothing device in figure 2 with pressure valve in the open configuration with indication of the reference sections and dimensions.

[0011] With reference to figure 1, a coffee maker 1 comprises a boiler 2 consisting of a container, preferably made in one piece, generally made of steel or aluminum.

[0012] The boiler 2 comprises a bottom 4 which is intended to be placed on a cooktop, e.g. a gas burner, an electric burner, an induction burner and the like.

[0013] According to an embodiment, the boiler bottom 4, typically if it is made of aluminum, comprises a plurality of inserts made of ferromagnetic material, such as steel, to allow the use of the coffee maker on an induction burner.

[0014] The boiler 2 further comprises an annular boiler wall 6, protruding from the bottom 4, ending at the top with a boiler mouth 8, typically provided with a thread 10.

[0015] Preferably, the coffee maker 1 comprises a safety valve 12, preferably inserted through the thickness of the boiler wall 6.

[0016] For example, the safety valve is manufactured according to the document EP-A1-1797360 in the name of the Applicant, the contents of which are expressly incorporated herein.

[0017] The boiler 2 thus has an inner boiler chamber 14 delimited by the boiler bottom 4 and the boiler wall 6.

[0018] The coffee maker 1 further comprises a dosing funnel 20, housed in the boiler chamber 14, typically supported by the edge of the boiler mouth 8.

[0019] The dosing funnel 20 comprises a dosing duct 22 for the rising of the water from the boiler chamber 14, which flows into a dosing chamber 24, intended to contain the ground coffee.

[0020] The dosing duct 22 and the dosing compartment 24 are preferably separated by a dosing filter 26, generally consisting of a perforated foil, provided to prevent the ground coffee from penetrating the dosing duct 22.

[0021] The coffee maker 1 further comprises a container 30 for the collection of the percolated beverage, to be coupled with the boiler 2.

[0022] The container 30 comprises a connection region 32 to mechanically engage with the boiler 2. For example, said connection region 32 consists of an annular connection wall 34, e.g. internally threaded, for screwing onto the boiler mouth 8.

[0023] The container 30 further comprises a container bottom 36, from which said attachment region 32 preferably protrudes downwards, and an annular container wall 38, which projects upwards from the container bottom 36, thus delimiting a container chamber 40 for the collection of the percolated beverage.

[0024] Preferably, the container wall 38 has a portion shaped to form a spout 39 to pour the beverage contained in the container chamber 40.

[0025] The container 30 further comprises a pipe 42 protruding vertically from the container bottom 36, open below, through a pipe inlet 44 that opens through the container bottom 36, and above, through a pipe mouth 46, for the outflow of the percolated beverage.

[0026] Along the pipe 42, the pipe inlet 44 is in communication with the pipe mouth 46 through an inner pipe duct 45.

[0027] Preferably, the container 30 is made as a single piece body, usually of steel or aluminum.

[0028] Depending on the variant embodiment, the container is made of ceramic or glass and has inserts for engagement with the boiler 2.

[0029] Preferably, the coffee maker 1 comprises a beverage filter 50 placed between the dosing compartment 24 and the pipe inlet 44, for example consisting of a perforated foil, to filter the percolated beverage before it passes through the pipe 42.

[0030] Preferably, said beverage filter 50 is held in place by a gasket 52 made of rubber, e.g. NBR rubber, EPDM or silicone .

[0031] Preferably, moreover, the coffee maker 1 comprises a handle 60, applied to the container 30, and a cover 70 hinged to the container 30 and rotatable for inspecting the container chamber 40; preferably, the cover 70, in the closed configuration, does not cover the spout 39.

[0032] With reference to figures 2 to 5, the coffee maker 1 comprises a frothing device 79, applied to the top of the pipe 42.

[0033] The frothing device 79 comprises a main body 80 arranged along the pipe duct 45, preferably upstream of the pipe mouth 46, to intercept the beverage in transit.

[0034] The main body 80 is fitted with at least one main duct 82 passing through said main body 80, having a very small passage section compared to the passage section of the pipe duct 45 upstream of the main body 80. In other words, said main duct 82 achieves a strong restriction of the passage section.

[0035] For example, the main pipe 82 has a passage section with a characteristic dimension D, e.g. defined by a diameter, if the section is circular, ranging from 0.8 to 1.2 mm.

[0036] This main duct 82 also has a characteristic length C ranging from 6 to 10 millimeters.

[0037] For said main duct 82 a characteristic ratio D/C is defined, preferably between 0.05 - 0.5, preferably between 0.08 - 0.2, preferably equal to 0.125.

[0038] Preferably, moreover, the material constituting the side wall 82a that delimits peripherally said main duct 82 is selected to increase the adhesion of the beverage inside the duct in the characteristic temperature conditions. Alternatively, the contact surface between the beverage and the side wall of the main duct is treated to increase adhesion.

[0039] For example, the entire main body 80 is made of silicone .

[0040] According to a variant embodiment, the main body provides for a plurality of main ducts, for example, parallel to each other, which on the whole satisfy the dimensional requirements mentioned above.

[0041] Downstream of the main duct 82, the frothing device 79 has a primary expansion chamber 90 with a passage section much larger than the passage section of the main duct 82, in order to obtain a sudden decrease in the speed of the beverage arriving from the main duct 82.

[0042] Preferably, the main duct 82 opens into the primary chamber 90 without connecting sections, so that the change in passage section is sudden.

[0043] For example, the passage section of said primary chamber 90 has a characteristic dimension H, for example a diameter in the case of a circular cross-section ranging from 4 - 8 millimeters.

[0044] A characteristic ratio D/H is defined between the characteristic dimension D of the passage section of the main duct 82 and the characteristic dimension H of the passage section of the primary chamber 90, ranging from 0.1 - 0.3, preferably from 0.15 - 0.18, preferably equal to 0.17.

[0045] Preferably, the frothing device 79 comprises a nozzle 92, to which the main body 80 is applied, in which said primary chamber 90 is defined.

[0046] For example, the nozzle 92 comprises a wider nozzle head 92a and a narrower nozzle shank 92b.

[0047] Preferably, the nozzle 92 is applied to the pipe mouth 46, for example by means of the nozzle shank 92b, preferably with a sealing ring 94 in between, while the main body 80, supported by the nozzle 92, is inserted into the pipe duct 45.

[0048] Additionally, the frothing device 79 comprises a secondary duct 96 downstream of the primary chamber 90, having a passage section much smaller than the passage section of the primary chamber 90.

[0049] For example, the secondary duct 96 has a passage section with a characteristic dimension A, e.g. defined by a diameter, if the cross-section is circular, ranging from 1.7 - 2.7 mm.

[0050] A characteristic ratio A/H is defined between the characteristic dimension A of the passage section of the secondary duct 96 and the characteristic dimension H of the passage section of the primary chamber 90, preferably ranging from 0.2 - 0.7, preferably from 0.3 - 0.5, preferably equal to 0.37.

[0051] Preferably, said secondary duct 96 is obtained in said nozzle 92, downstream of the primary chamber 90.

[0052] Additionally, the frothing device 79 comprises a secondary expansion chamber 100 having a characteristic section much larger than the passage section of the secondary duct 96.

[0053] For example, the secondary chamber 100 has a characteristic section, e.g. assessed immediately at the outlet of the secondary duct 96, with characteristic dimension L, for example a diameter, in the case of a circular section, greater than 20 millimeters.

[0054] A characteristic ratio A/L is defined between the characteristic dimension A of the passage section of the secondary duct 96 and the characteristic dimension L of the characteristic section of the secondary chamber 100, preferably less than 0.1, preferably less than 0.09, e.g. 0.08.

[0055] According to a variant embodiment, the frothing device has no secondary duct and the primary chamber opens directly into the secondary chamber.

[0056] The secondary chamber 100 is suitable to communicate with the container chamber 40, to dispense the beverage therein, according to the configuration assumed by a pressure valve 110 of the frothing device 79, operatively placed between said secondary chamber 100 and the container chamber 40.

[0057] For example, said pressure valve is manufactured according to the International Application WO-A1-98/ 17160 in the name of the Applicant, the teaching of which is hereby expressly incorporated.

[0058] In particular, said pressure valve 110 is normally closed (closed configuration) and is suitable to pass into an open configuration, wherein it connects the secondary chamber 100 with the container chamber 40, when a predefined pressure value, defined as threshold pressure p*, is exceeded in the secondary duct 96.

[0059] According to a preferred embodiment, said pressure valve 110 comprises a shutter 112, which in the closed configuration closes the secondary duct 96, for example, resting on the nozzle 92.

[0060] For example, the shutter 112 consists of a disc made of polymeric material, suitable for sealing.

[0061] The pressure valve 110 further comprises a mass 114, which presses on the shutter 112 by gravity.

[0062] For example, said mass 114 is comprised of a body, shaped like an upside-down glass, inside of which the shutter 112 is housed.

[0063] Preferably, moreover, the pressure valve 110 comprises a lock ring 116 for holding the shutter 112 inside the mass 114.

[0064] For example, said lock ring 116 comprises an annular ring wall 118, preferably threaded externally, which extends from an upper edge 118a to a lower edge 118b, thus peripherally delimiting a valve compartment 119, and a ring flange 120, protruding radially outside the lower edge 118b of the ring wall 118. Preferably, the ring flange 120 protrudes radially from the ring wall 118 also internally .

[0065] The shutter 112 is housed in the mass 114, and the ring wall 118 of the ring 116 is screwed to said mass 114, so that the upper edge of the shutter 112 is in contact therewith, thus holding it inside the mass 114.

[0066] The nozzle shank 92b is screwed to the pipe mouth 46, while the nozzle head 92a is accommodated in the valve compartment 119; the ring 116, which carries the mass 114, is movable with respect to the nozzle 92, by virtue of the size of the valve compartment 119, without being able to be removed therefrom, due to the inner abutment created by the ring flange 120.

[0067] When the pressure of the beverage in the secondary duct 96 is lower than the threshold pressure p*, the pressure valve 110 is in the closed configuration wherein the shutter 112 is positioned on the nozzle 92 and closes said secondary duct 96. In such a configuration, the secondary chamber 100 is practically non-existent.

[0068] Once the threshold pressure p* has been exceeded, the action of the pressure on the shutter 112 overcomes the action of the weight of the mass 114 and the ring 116, lifting both bodies; the pressure valve thus moves into the open configuration, wherein the beverage flows out of the secondary duct 96 and is collected in the collecting chamber 40.

[0069] In the open configuration, the distance between the outlet opening of the secondary duct 96 and the shutter 112 determines the height of the secondary chamber 100. [0070] In the normal use of the coffee maker according to the present invention, for the preparation of the beverage, the boiler chamber 14 is filled with a known volume of water, generally indicated by the height of the safety valve 12, or by the height of a reference (a turning or a notch in relief) present in the boiler 14 or in the container 30. When the dosing funnel 20 is inserted, the dosing compartment 24 is filled with ground coffee .

[0071] The boiler 2 is then fitted with the container 30, e.g. by screwing.

[0072] When the coffee maker is placed on the cooktop and has started heating the water, the pressure valve 110 is initially in the closed configuration.

[0073] By the action of the super-saturated steam that forms in the boiler chamber 14, the water rises through the dosing duct 22 and floods the dosing compartment 24, extracting the essential oils from the ground coffee.

[0074] The beverage thus formed, filtered through the beverage filter 50, rises up through the pipe duct 45 and finally presses against the shutter 112 of the pressure valve 110, under practically static conditions.

[0075] When the pressure of the beverage against the shutter 112 exceeds the threshold pressure p*, the pressure valve 110 opens and the beverage begins to flow towards the container chamber 40.

[0076] In such conditions, the beverage passes from the pipe duct 45 to the main duct 82 and from there to the primary chamber 90.

[0077] Due to the sudden variation of the passage section from the main duct 82 to the primary chamber 90, the flow is abruptly slowed.

[0078] Subsequently, the beverage passes through the secondary duct 96 and from there into the secondary chamber 100, undergoing a new, sudden slowdown.

[0079] The Applicant has found that the succession of sudden increases and decreases in the speed of the beverage, in combination with the features of the main body, cause the formation of a dense and compact foam, as evidenced by the beverage collected in the container 30.

[0080] Innovatively, the coffee maker according to the present invention meets the needs of the sector, as it allows a beverage with a dense and compact foam to be obtained, while maintaining a high simplicity of construction and assembly.

[0081] It is clear that one skilled in the art may make modifications to the above-described coffee maker and frothing device, all contained within the scope of protection as defined by the following claims.