Method of correction of the amount of coffee powder dispensed by a coffee grinder

Abstract

Method of correction of the amount of coffee powder dispensed by a coffee grinder into a filter (21, 21'), wherein the filters of different types used all have an upper cylindrical internal free volume with the same diameter, and within that upper cylindrical free volume, a reference fill level at the same distance from the top opening for introducing the coffee powder, the method provides for calculating a correction volume based on the known diameter and the detected deviation between the actual fill level and the reference fill level.

Description

[0001] METHOD OF CORRECTION OF THE AMOUNT OF COFFEE POWDER DISPENSED BY A

[0002] COFFEE GRINDER

[0003] DESCRIPTION

[0004] The present invention relates to a method of correction of the amount of coffee powder dispensed by a coffee grinder.

[0005] The field of application is that of coffee machines where coffee powder is dispensed into a filter housed in a portafilter to perform the infusion process at a dedicated station of a coffee machine. One of the crucial steps in achieving high-quality espresso is the tamping process of the coffee powder inside the portafilter.

[0006] In manual and semi-automatic coffee machines, which use a removable arm-type portafilter, after grinding, i.e. after filling the filter with a certain dose of loose coffee, a tool called a tamper is used to apply pressure to the loose coffee powder, forming a compacted powder coffee puck. In this way, once the portafilter is locked into the brewing group of the coffee machine, the water encounters adequate resistance as it passes through, the infusion pressure increases, and the flow is slowed down to match the optimal parameters for espresso.

[0007] All other parameters being equal, the correct height of this coffee puck ensures proper extraction of the organoleptic components of roasted coffee.

[0008] Often, the final result depends on the user's skill, who must rely on trial and error to achieve the desired outcome.

[0009] Further complicating the situation is the fact that for proper grinding management, it is important to know the type of filter used for the infusion, as different filter types vary in volumetric capacity. Each filter type is generally associated with a specific type of beverage, such as single or double shots, hot, cold, etc.

[0010] Therefore, each type of filter, and consequently its volumetric capacity, corresponds to a specific amount of coffee powder required to carry out a proper infusion. Furthermore, for each type of filter there is an optimal filter filling time, which depends not only on the volume of the filter, but also on the degree of grinding of the coffee, the degree of roasting of the coffee, and the botanical variety of the coffee.

[0011] The technical objective of this invention is therefore to provide a method of correction of the amount of coffee powder dispensed by a grinder, aimed at eliminating the technical drawbacks of the known art.

[0012] Within the scope of this technical objective, an object of the invention is to provide a method of correction of the amount of coffee powder dispensed by a coffee grinder, which makes it possible to obtain the required amount of coffee powder for carrying out a correct brewing process depending on the type of filter used.

[0013] A further object of the invention is to provide a method of correction of the amount of coffee powder dispensed by a coffee grinder, which can assist the user in the proper management of the grinding process.

[0014] The technical task, as well as these and other objectives, are achieved according to the present invention by means of the method as claimed in claim 1.

[0015] The invention is based on using filters of different types, all featuring an upper cylindrical free internal volume with the same diameter and, within this upper cylindrical free volume, an ideal reference fill level located at the same distance from the top opening for the introduction of coffee powder.

[0016] Therefore, regardless of the type of filter used, by knowing the diameter and the aforementioned ideal reference fill level, it is always possible to derive a correction volume that is independent of the volumetric capacity of the filter itself.

[0017] Further characteristics and advantages of the invention will become more evident from the description of a preferred but non-exclusive embodiment of the method of correction of the amount of ground coffee powder according to the invention, which is provided by way of example and not limitation in the attached drawings, in which:

[0018] Figure 1 shows an isometric view of an assembly including a portafilter and a ring used in a coffee powder tamping system applicable for executing the method of the invention;

[0019] Figure 2 shows an isometric view of the portafilter and ring assembly positioned in a support cradle;

[0020] Figure 3 shows an isometric view of the ring;

[0021] Figure 4A shows a cross-sectional view of the portafilter and ring assembly positioned in the support cradle;

[0022] Figure 4B shows the support cradle;

[0023] Figures 5A and 5B show isometric views of the tamper;

[0024] Figure 6 shows a side elevation and vertical section view of the tamper in an operational position;

[0025] Figure 7 shows a side elevation view of the tamper in different operational positions, each corresponding to a different puck height of coffee powder;

[0026] Figure 8 shows a side elevation view and central vertical section of a first type of filter;

[0027] Figure 9 shows a side elevation view and central vertical section of a second type of filter;

[0028] Figure 10 shows the filter from Figure 8 filled with an excessive amount of coffee powder;

[0029] Figure 11 shows the filter from Figure 9 filled with an insufficient amount of coffee powder.

[0030] With reference to the cited figures, an apparatus is shown for preparing a puck 100 of compacted coffee powder.

[0031] For simplicity and clarity, the complete coffee grinder, of known type, is not illustrated in the figures.

[0032] The apparatus for preparing a puck of compacted coffee powder comprises a portafilter 1 equipped with a filter 21, 21 ’. It is possible to use a single portafilter 1 to which different types of filters 21, 21’ can be attached as needed, or alternatively, a plurality of portafilters may be provided, each housing a filter 21, 21’ of a different type.

[0033] The filters 21, 21 ’ of different types feature an upper filter part 110, 110’ with a top opening 24, 24’ for introducing the coffee powder 100, and a lower filter part 111, 111 ’ with a filtering base 112, 112’.

[0034] The upper filter part 110, 110’ of the filters 21, 21’ of different types has the same internal geometry while the lower filter part 111, 111’ of the filters 21, 21’ of different types has different internal geometries.

[0035] The filters 21 , 21’ of different types define a total free internal volume V, V’ composed of an upper cylindrical free internal volume VI, VI’ (shown in Figures 8 and 9 as a hatched rectangular region) bounded by the upper filter part 110, 110’ and a lower free internal volume V2, V2 (shown in Figures 8 and 9 as a hatched trapezoidal region) bounded by the lower filter part 111, 111 ’.

[0036] The upper cylindrical free internal volume VI, VI’ of the filters 21, 21’ is a cylinder whose axis coincides with the vertical central z-axis of the filter 21, 21 ’.

[0037] In practice, this yields:

[0038] V = VI + V2

[0039] V’ = V’l + V’2

[0040] All types of filters 21, 21’ suitable for correctly executing the method according to the invention share the same diameter value D of the upper cylindrical free internal volume VI, VI ’. The filters 21, 21 ’ of different types can be filled up to specific fill levels X, X’ within the upper cylindrical free internal volume VI, VI’.

[0041] These fill levels correspond to an axial height within the filters 21, 21 ’ measured below the top opening 24, 24’. In practice, taking the vertical central z-axis of symmetry of the filters 21, 21’, the orthogonal plane 0 in which the top opening 24, 24’ of the filters 21, 21 ’ lies serves as a reference plane from which the fill level of the filters 21, 21 ’ can be uniquely identified regardless of the type and therefore of the volumetric capacity.

[0042] The method of correction of the amount of coffee powder dispensed by the grinder into the filter 21, 21’ includes a preliminary step of storing, in memory accessible by an electronic controller, geometric parameters of the filters 21, 21’ of different types.

[0043] The electronic controller may be that of the coffee grinder, if the coffee grinder is of the standalone type, or that of the coffee machine if the coffee grinder is structurally and functionally integrated into the coffee machine.

[0044] Consequently, the memory may reside in the grinder or the coffee machine.

[0045] These geometric parameters include the diameter value D of the upper cylindrical free internal volume VI, VI’ of the filters 21, 21’ of different types and a reference fill level value Xr, which is advantageously the same across all filter types 21, 21’.

[0046] The method of correction of the amount of coffee powder dispensed by the coffee grinder into the filter 21, 21' advantageously also provides for storing, in the memory accessible to the electronic controller, a value t, t' of the activation time duration of the coffee grinder relating to at least the grinding cycle preceding the one to be performed, for each type of filter 21, 21'.

[0047] The stored value t, t' of the activation time duration of the coffee grinder is instead a factory-set value if the coffee grinder is to perform the very first grinding cycle for a given type of filter 21, 21'.

[0048] The method then includes first detecting and transmitting to the electronic controller an indication of the type of filter 21, 21 ’ selected for filling in the current grinding cycle.

[0049] The electronic controller performs the current grinding cycle by activating the grinder for the stored duration time t, t’ corresponding to the selected type of filter 21, 21 ’. From the current grinding cycle, a correction is calculated for the next grinding cycle with the same filter type 21, 21’.

[0050] In particular, an indication of any deviation AX, AX’ between the achieved filling level value Xc, X’c and the reference filling level value Xr is detected and transmitted to the electronic controller. The electronic controller carries out the correction of the activation time duration value tc, t'c of the coffee grinder for performing the subsequent grinding cycle in which a filter 21, 21' of the same type as in the current grinding cycle is selected.

[0051] The correction value At, At’ is calculated as the ratio between a cylindrical volume Vc with a diameter equal to the diameter D of the upper cylindrical free internal volume V 1 , V 1 ’ and a height equal to the deviation AX, AX’ between the achieved filling level value Xc, X’c and the reference filling level value Xr, and the volumetric flow rate of the grinder Q, Q’ associated with the selected filter type 21, 21’.

[0052] In other words: tc = t + At, where At = Vc / Q = AX-TI D2 / 4Q, and t’c = t’ + At’, where At’ = V’c / Q’ = AX’ -JI-D2 / 4Q’

[0053] A correction parameter can be associated with the volume Vc, V’c, taking into account possible measurement errors in detecting the deviation AX, AX’.

[0054] The deviation AX, AX’ can be measured by inserting a graduated tamper 101 into the filter 21, 21’.

[0055] The graduated tamper 101 can be manually inserted into the filter 21 , 21 ’ for compacting the coffee powder and thereby forming a coffee powder puck.

[0056] The deviation value AX, AX’ can be transmitted to the electronic controller via a physical user interface or through telecommunication means. The type of filter 21, 21 ’ may be visually identified by the user and communicated to the electronic controller through the user interface or it may be automatically recognized via identification means located on the filter 21, 21’.

[0057] The volumetric flow rate of the grinder Q, Q’ for each type of filter 21, 21 ’ can be a theoretical value stored in memory accessible by the electronic controller and it can be defined according to the degree of roasting of the coffee and / or the degree of grinding of the coffee and / or the botanical variety of the coffee.

[0058] Alternatively, the volumetric flow rate of the grinder Q, Q’ can also be a practical value calculated as the ratio between the volume of coffee ground and the grinding time. In this case, the electronic controller must also store the lower internal free volume of the selected filter; knowing this, along with the fill level of the filter and the activation time duration of the grinder of the current cycle, the grinder’s volumetric flow rate Q, Q’ can be easily calculated.

[0059] By way of example only, a grinding system suitable for executing the method of correction is described below.

[0060] The portafilter 1 is coupled with a removable ring 10 that contains the coffee powder. The portafilter 1 includes an arm 30 for manual gripping and a cup-shaped housing 20 for the filter 21, 21’.

[0061] The cup-shaped housing 20 has an opening 23 for inserting the filter 21, 21 ’.

[0062] The coffee powder retaining ring 10 is removably attached to the housing 20 of the portafilter 1 so as to protrude outwardly from the opening 23 for introducing the filter 21, 21'.

[0063] The ring 10 features an internal annular guide surface 13 with a rotational symmetry axis L passing through the center C of the circular opening 24 of the filter 21, 21’.

[0064] The rotational symmetry axis L is therefore coaxial with the z-axis of the filter 21, 21 ’ housed in the portafilter 1. The tamper 101 includes a handle 102 and a pressing piston 103, which slides along the internal annular guide surface 13 of the ring 10.

[0065] The pressing piston 103 has a front surface 104 shaped to match the circular opening 24, 24’ of the filter 21, 21 ’ and a lateral surface 105 shaped to match the internal annular guide surface 13 of the ring 10.

[0066] The lateral surface 105 of the pressing piston 103 and the internal annular guide surface 13 of the ring 10 are cylindrical.

[0067] The pressing piston 103 preferably has a dimension P generally greater than the dimension A of the ring in the direction of the rotational symmetry axis Lw to protrude from the ring 10 on the handle side 102 by a height portion that varies according to the height H of the compacted coffee powder puck 100.

[0068] The dimension P may also be smaller than the dimension A, but in this case the dimensions must be such as to still ensure adequate guidance.

[0069] Advantageously, the pressing piston 103 and the ring 10 cooperatively have visual indication means of the height H of the compacted coffee powder puck 100, namely the dimension of the puck 100 in the direction of the rotational symmetry axis L, and / or any deviation thereof from a reference height.

[0070] The visual indication means specifically indicate the relative position between the pressing piston 103 and the ring 100.

[0071] In the illustrated case, the visual indication means comprise a graduated scale 106 provided on the lateral surface 105 of the pressing piston 103.

[0072] In the illustrated case, the visual indication means also comprise a reference position provided by the ring 10. In particular, the graduated scale 106 has marks 107 placed at various heights along rotational symmetry axis L, while the reference position is provided by the edge 108 of the ring 10 farthest from the filter housing 20 of the filter 21, 21’.

[0073] Each mark 107 is associated with a different alphanumeric symbol having a meaning that can be immediately related to the filling level of the filter 21, 21'.

[0074] For example: a central mark 107 is associated with the symbol “0” which identifies a correct filling level of the filter 21 , 21'; on one side of the central mark 107, facing towards the handle 102, marks 107 are arranged that are associated with progressively increasing negative numbers indicating a filling level increasingly lower than the reference filling level; and, on the side of the central mark 107, facing towards the front surface 104 of the tamper 101, mark 107 are arranged that are associated with progressively increasing positive numbers indicating a filling level increasingly greater than the reference filling level.

[0075] In practice, after the grinder dispenses the coffee powder into the filter 21, 21’, the user handles the tamper 101 and inserts the pressing piston 103 into the ring 10 attached to the housing 20 portafilter 1.

[0076] The pressing piston 103 initially levels the loose coffee powder dose, and its penetration into the ring 10 ends when the loose coffee powder dose, completely leveled and compacted, becomes a compacted puck 100.

[0077] At this point, the user checks which mark 107 is aligned (or closest) to the reference 108 and the symbol associated with this mark 107 immediately indicates whether there is a deviation AX, AX’, and the amount thereof.

[0078] For example, in the case of filling the filter 21 of Figure 10, to the filling level Xc exceeding the correct filling level Xr, with AX = Xr - Xc > 0, there corresponds a mark 107 associated with a positive number, whereas in the case of filling the filter 21 of Figure 11, to the filling level X'c lower than the correct filling level Xr, with AX' = Xr - X'c < 0, there corresponds a mark 107 associated with a negative number.

[0079] At this point, the user, via the physical user interface provided on the coffee grinder or on the coffee machine in which the grinder may be integrated, can communicate to the electronic controller the indication supplied by the visual indication means obtained from the current grinding cycle, and the electronic controller by means of the above-mentioned calculation algorithm can thus automatically adjust the subsequent grinding cycle using the received indication.

[0080] The user interface of the coffee grinder or of the coffee machine may be a display viewer or a keyboard or a knob or something else.

[0081] In a more sophisticated solution, not shown, the tamper 101, as mentioned, may have telecommunication means for communicating to the electronic controller the indication provided by the visual indication means.

[0082] For example, the information may be transmitted via a wireless communication network such as Bluetooth or the like.

[0083] In this case, the tamper 101 must be provided with a transducer capable of converting the indication into a signal to be transmitted to the grinder control unit via the wireless communication network. It should be noted that, in the case of excessive grinding of coffee powder, the filter must be partially emptied manually if it is desired to correct the amount of its contents for infusion, whereas, in the case of insufficient grinding of coffee powder, the user may command extra grinding of duration At, At' if it is desired to correct the amount of its contents for infusion.

[0084] With reference to the grinder, of a known type, it comprises a cradle 50 for housing the filter holder 1 during the loading phase of the ground coffee.

[0085] The cradle 50 has, above the filter holder 1, a support shelf 51 delimiting an opening 52 for the passage, by gravity, of the ground coffee towards the filter 21, 2 T.

[0086] The support shelf 51 has a front discontinuity at the insertion axis of the portafilter 1. The ring 10 connects the opening 52 in the support shelf 51 to the upper mouth 23 of the housing

[0087] 20 ofthe filter 21, 21'.

[0088] The ring 10 has lower means for quick release and coupling to the upper mouth 23 of the housing 20 of the filter 21, 21' and upper means for removable engagement with the support shelf 51.

[0089] The upper means for removable engagement of the ring 10 with the support shelf 51 comprise a peripheral flange 12 configured to rest along a peripheral surface 53 of the opening 52 in the support shelf 51.

[0090] The lower means for quick release and coupling of the ring 10 comprise resiliently deformable seats 15 for engagement with fins 22 of the housing 20 of the filter 21, 21'.

[0091] The cradle 50 has, above the support shelf 51, an anti-tilt shelf 54 for the ring 10, configured and arranged to interact with the peripheral flange 12.

[0092] Beneath the cradle 50, there is provided an actuator 60 of a coffee grinder activation switch, adapted to interact with the ring 10.

[0093] The method of correction of the amount of coffee powder dispensed by a coffee grinder, as conceived, is susceptible to numerous modifications and variations, all falling within the scope of the inventive concept; furthermore, all details may be replaced by technically equivalent elements. In this regard, for detecting and communicating the level reached by the coffee powder, the graduated tamper may be replaced by a different system for automatically detecting the level reached by the coffee powder, in particular a non-contact level sensor such as, but not necessarily, an ultrasonic sensor.

Claims

CLAIMS1. Method of correction of the amount of coffee powder dispensed by a coffee grinder into a filter (21, 21') housed in a filter holder (1) of a coffee machine, wherein the filter (21, 21') has an upper filter portion (110, 110') having an upper mouth (24, 24') for the introduction of the coffee powder ( 100) and a lower filter portion (111, 111') having a filtering base (112, 112'), wherein the filter (21, 21') defines a total internal free volume (V, V') formed by a first upper cylindrical internal free volume (VI, VI ') delimited by the upper filter portion (110, 110') and a second lower internal free volume (V2, V2') delimited by the lower filter portion (111, 111'), and wherein the filter (21, 21') is fillable so as to achieve, in said first upper cylindrical internal free volume (VI, VI'), a filling level (X, X') identified by an axial height below said upper mouth (24, 24'), characterized in that it comprises the following steps: storing, in a memory accessible to an electronic controller: geometric parameters of different types of filters (21, 21') having an upper filter portion (110, 110') of identical internal geometry, a lower filter portion (111, 111') of different internal geometry, wherein said geometric parameters include a value (D) of the diameter of the upper cylindrical internal free volume (VI, VI') of the filter (21, 21'), which is the same for all types of filters (21, 21'), and a reference filling level value (Xr) which is the same for all types of filters (21, 21'); and a value (t, t') of the activation time duration of the grinder, which is different for each type of filter (21, 21'); detecting and transmitting to the electronic controller an indication of the type of filter (21 , 21') selected for a current grinding cycle; filling the filter (21, 21') selected by activating the grinder, by the electronic controller, for the activation time duration value (t, t') stored for the selected type of filter;detecting and transmitting to the electronic controller an indication of any deviation (AX, AX’) between the achieved filling level value (Xc, X’c) and the reference filling level value (Xr);- performing, by the electronic controller, the correction of the activation time duration value (tc, t'c) of the grinder for carrying out a subsequent grinding cycle in which a filter (21, 21') of the same type as the current grinding cycle is selected, wherein the value of said correction (At, At') is calculated as the ratio between a cylindrical volume (Vc, V'c) having a diameter equal to the diameter (D) of the upper cylindrical internal free volume (VI , VI ') and a height equal to the deviation (AX, AX') between the achieved filling level value (Xc, X'c) and the reference filling level value (Xr), and a volumetric flow rate of the grinder (Q, Q') associated with the selected type of filter (21, 21').

2. Method of correction according to claim 1, characterized in that said deviation (AX, AX') is detected by inserting a graduated tamper (101) into said filter (21, 21') or by means of a noncontact level sensor.

3. Method of correction according to the preceding claim, characterized in that said graduated tamper (101) is inserted manually into said filter (21, 21 ’).

4. Method of correction according to any of claims 2 and 3 , characterized in that the deviation value (AX, AX’) is transmitted to said electronic controller via a physical user interface.

5. Method of correction according to any of claims 2 and 3, characterized in that the deviation value (AX, AX’) is transmitted from said tamper (101) to said electronic controller via telecommunication means.

6. Method of correction according to claim 1 , characterized in that said type of filter (21, 21 ’) is visually identified and transmitted to said electronic controller via a physical user interface.

7. Method of correction according to claim 1 , characterized in that said type of filter (21, 21 ’) is detected via automatic recognition of identification means provided on the filter (21, 21’).

8. Method of correction according to claim 1, characterized in that the volumetric flow rate of the grinder (Q, Q’) for each type of filter (21, 21’) is a theoretical value stored in said memory and defined also based on the degree of grinding of the coffee and / or on the degree of roasting of the coffee, and / or on the botanical variety of the coffee.

9. Method of correction according to claim 1, characterized in that the volumetric flow rate of the grinder (Q, Q’) for each type of filter (21, 21’) is a practical value, calculated as the ratio between the volume of ground coffee dispensed and the grinder activation time during the current grinding cycle.

10. A coffee grinder or coffee machine incorporating a grinder, adapted to perform a method according to any of the preceding claims for correcting the quantity of ground coffee dispensed.

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