Method and apparatus to grind a product

Abstract

A method and an apparatus are described to grind a product, for example a product in grain form, which provide to compare a value of estimated weight (pk*) with a predefined quantity (pTARGET) that has to be delivered in a delivery cycle, and that has been set by the user. The value of estimated weight (pk*) is calculated by adding a weight (pk) detected at successive instants (tk) of the delivery cycle with a suitable correction factor (C).

Claims

1. A method to grind a product in grain form by a grinding device within each delivery cycle, wherein said grinding device is driven by drive means, said drive means is commanded by a control and management unit so as to start and stop said grinding device, wherein said method comprises: starting a first delivery cycle, by setting a predefined quantity (p.sub.TARGET) of said ground product for said first delivery cycle and defining an initial instant (t.sub.START); grinding said product and delivering said ground product on a collection element; continuously detecting an instantaneous weight (P.sub.k(t.sub.k)) of said ground product on said collection element until an estimated weight (p.sub.k*) is greater than or equal to said predefined quantity (p.sub.TARGET), wherein said estimated weight (p.sub.k*) is a sum of a correction factor (C) and said instantaneous weight (P.sub.k(t.sub.k)) commanding said drive means to stop said grinding device and defining an instant (t.sub.COM); consequently delivering said ground product on the collection element until said grinding device actually stops and defines a final instant (t.sub.FIN); determining a quantity difference of said ground product (Δp) that is delivered between said instant (t.sub.COM) and said final instant (t.sub.FIN); and updating said correction factor (C) used for a second delivery cycle based on said quantity difference (Δp) in the first delivery cycle; wherein said quantity difference (Δp) is a constant and characteristic value for each delivery cycle.

2. The method according to claim 1, wherein the updating said correction factor (C) used for the second delivery cycle based on said quantity difference (Δp) in the first delivery cycle comprises: processing an error (E) by subtracting said predefined quantity (p.sub.TARGET) from said estimated weight (p.sub.k*); and updating said correction factor (C) used for the second delivery cycle based on said quantity difference (Δp) and said error (E) in the first delivery cycle.

3. The method according to claim 2, further comprising: storing said error (E) calculated during a last delivery cycle of a first working day when said grinding device is switched off; and using said error (E) calculated during the last delivery cycle of the first working day in a first delivery cycle of a second working day.

4. The method according to claim 1, further comprising setting the predefined quantity (p.sub.TARGET) through a user interface.

5. The method according to claim 1, further comprising: storing said quantity difference (Δp) calculated during a last delivery cycle of a first working day even when said grinding device is switched off; and using said quantity difference (Δp) calculated during the last delivery cycle of the first working day in a first delivery cycle of a second working day.

6. The method according to claim 1, wherein the first delivery cycle immediately precedes the second delivery cycle.

7. The method according to claim 1, further comprising: starting the second delivery cycle, by defining an initial instant (t.sub.START) for said second delivery cycle; grinding said product and delivering said ground product on a collection element; continuously detecting a second instantaneous weight (P.sub.k(t.sub.k)) of said ground product on said collection element until a second estimated weight (p.sub.k*) is greater than or equal to said predefined quantity (p.sub.TARGET), wherein said second estimated weight (p.sub.k*) is a sum of the updated correction factor (C) and said second instantaneous weight (P.sub.k(t.sub.k)) commanding said drive means to stop said grinding device and defining a second instant (t.sub.COM); consequently delivering said ground product on the collection element until said grinding device actually stops and defines a second final instant (t.sub.FIN); determining a quantity difference of said ground product (Δp) for the second delivery cycle that is delivered between said second instant (t.sub.COM) and said second final instant (t.sub.FIN); and updating said correction factor (C) used for a third delivery cycle based on said quantity difference (Δp) in the second delivery cycle; wherein said updated correction factor (C) used for the third delivery cycle differs from the updated correction factor (C) used for the second delivery cycle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other characteristics of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

(2) FIG. 1 is a diagram showing the method to grind a product according to the invention,

(3) FIG. 2 is a perspective view of an apparatus to grind a product according to the invention,

(4) FIG. 3 is a plan view from above of the apparatus in FIG. 2;

(5) FIG. 4 is a cross section of the apparatus in FIG. 2 taken according to the section plane IV-IV visible in FIG. 3.

(6) To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

(7) We will now refer in detail to the various embodiments of the present invention, of which one or more examples are shown in the attached drawings. Each example is supplied by way of illustration of the invention and shall not be understood as a limitation thereof. For example, the characteristics shown or described insomuch as they are part of one embodiment can be adopted on, or in association with, other embodiments to produce another embodiment. It is understood that the present invention shall include all such modifications and variants.

(8) With reference to FIG. 1, we will now describe a method according to the invention to grind a product. In particular, the method according to the invention can be advantageously used to grind a product in grains, or in beans, such as for example coffee.

(9) The drawing shows the steps relating to a plurality of delivery cycles 100, in which the steps relating to each delivery cycle are grouped together within a single broken line. By way of example, an n-th preceding delivery cycle 100A and an n+1-th subsequent delivery cycle 100B are visible.

(10) Each delivery cycle 100A, 100B has a duration comprised between an initial instant t.sub.START and a final instant t.sub.FIN. These instants are the instants in which the ground product respectively begins and ends actually being delivered.

(11) The method according to the invention comprises an initial step which provides to set a predefined quantity p.sub.TARGET of ground product which is desired to be obtained in a product delivery cycle 100. In particular, this step is implemented by a user who sets the desired value on a suitable user interface 13. The predefined quantity of ground product is delivered on a collection element 17.

(12) Subsequently, the method provides to grind the product by means of a grinding device 11 which is driven by drive means 12. The grinding device 11 and the drive means 12, visible in FIG. 2, will be described in greater detail below in the context of the detailed description of an apparatus 10 to grind a product according to the invention.

(13) The method to grind a product according to the invention also comprises a step 102 to detect at subsequent instants t.sub.k an instantaneous weight p.sub.k of the product delivered in correspondence with at least a plurality of instants k during a delivery cycle.

(14) The method comprises a step 103 to determine a quantity of ground product Δp which is delivered between an instant t.sub.COM in which the drive means 12 are commanded to stop the grinding device 11 and the final instant t.sub.FIN. The instant t.sub.COM is an instant comprised between the initial instant t.sub.START and the final instant t.sub.FIN. The quantity of ground product Δp determined in step 103 is calculated as the difference between the weights p.sub.FIN and p.sub.COM, that is, between the weight detected at the end of the delivery cycle (that is, at the instant t.sub.FIN) and the weight detected in correspondence the instant t.sub.COM.

(15) It should be noted that the instant t.sub.COM is the instant in which the drive means 12 receive the stop command, that is, the moment when they are deactivated.

(16) The method according to the invention also comprises a step 104 in which it is provided to correct a respective instantaneous weight p.sub.k of the product delivered on the collection element 17 which was detected in step 102 in correspondence with a plurality of respective instants t.sub.k, on the basis of the quantity of ground product Δp.

(17) In particular, in this step 104 the instantaneous weight p.sub.k is corrected on the basis of a correction factor C, which is a function of at least the quantity of ground product Δp determined in step 103.

(18) The correction of the instantaneous weight p.sub.k allows to calculate an estimated weight p.sub.k* for each of the instants t.sub.k, obtained by adding the correction factor C to the instantaneous weight p.sub.k.

(19) The method also provides step 105 to compare the estimated weight p.sub.k* with the predefined quantity p.sub.TARGET.

(20) When the result of the comparison between the estimated weight p.sub.k* and the predefined quantity p.sub.TARGET is such that the estimated value p.sub.k* is greater than, or equal to, the predefined quantity p.sub.TARGET, the method according to the invention provides the step 106 to command the drive means 12 so as to stop the grinding device 11, and terminate the delivery cycle.

(21) On the contrary, when the result of the comparison between the estimated weight p.sub.k* and the predefined quantity p.sub.TARGET is such that the estimated value p.sub.k* is lower than the predefined quantity p.sub.TARGET, then it is provided to continue the delivery of the ground product. During delivery, it is provided to continue to detect the weight p.sub.k (step 102) at one or more successive instants k.

(22) The method according to the invention also comprises a step 107 to process an error E by subtracting the predefined quantity p.sub.TARGET from the estimated weight p.sub.k*. In particular, the error E is not calculated for each instant k, but only once for each delivery cycle 100A, 100B. In fact, the calculation of the error E is performed with the value of estimated weight p.sub.k* such as to activate step 106, that is the first value of estimated weight p.sub.k* which is greater than or equal to the predefined quantity p.sub.TARGET.

(23) The method according to the invention then provides a step 108, which provides to calculate the correction factor C by adding together the difference Δp and the error E.

(24) In some embodiments, the step 103 to determine a quantity of ground product Δp in the manner explained above and step 107 to process an error E are related to a previous delivery cycle 100A, and these data are used to calculate the correction factor C (step 108) and then implement step 104, that is, to correct the respective instant weights p.sub.k, of a successive delivery cycle 100B.

(25) It should be noted that the difference Δp and error E are constant and characteristic values for each delivery cycle which remain unchanged at all instants t.sub.k of the same delivery cycle, and which are obtained as described above, on the basis of the data detected in an immediately preceding delivery cycle.

(26) In some versions of the method according to the invention, the quantity Δp and error E can remain memorized even when the apparatus 10 is switched off. In this case, in the first delivery cycle 100B of a new working day, the apparatus 10 uses the value of the quantity Δp and the error E calculated during the last delivery cycle 100A of the previous day.

(27) In some versions, the method according to the invention provides to memorize the predefined quantity p.sub.TARGET of weight of ground product set by the user for a plurality of delivery cycles. For example, it can be provided that the predefined quantity p.sub.TARGET is kept memorized until the user sets a new and different value of predefined quantity p.sub.TARGET, without the need for the user to set the predefined quantity p.sub.TARGET before each delivery cycle

(28) The apparatus 10 to grind a product, in particular a product in grains or in beans such as coffee for example, is able to implement the method to grind a product described above.

(29) The apparatus 10 according to the invention, visible in FIGS. 2-4, comprises a user interface 13 which allows a user to introduce at least the predefined quantity p.sub.TARGET of weight of ground product that is to be delivered in a delivery cycle 100.

(30) In some embodiments, the user interface can be a digital interface known in the state of the art.

(31) The apparatus 10 also comprises a containing element 14 configured to contain the product to be ground, in particular in the form of grains.

(32) The apparatus 10 comprises a grinding device 11 to grind the product and drive means 12 to drive the grinding device 11.

(33) In some embodiments, the grinding device 11 generally comprises a first crushing element 22 and a second crushing element 23 which interact with each other to crush the coffee beans. The two crushing elements 22, 23 can be, for example, a pair of mills (conical or flat) rotating with relative motion to each other.

(34) In some embodiments, one mill can be rotatable while the other can be stationary.

(35) Each crushing element 22, 23 is provided with a plurality of teeth (not shown) distributed on it and protruding toward the other element. The cooperation of the teeth of the two crushing elements 22, 23 allows to grind the coffee beans.

(36) As is known, the particle size of the ground product is a function of the distance between the crushing elements 22, 23, measured in the axial direction, that is, along a longitudinal axis X. The apparatus 10 therefore comprises a regulation device 25 by means of which a user can set the particle size of the ground product that he wants to obtain.

(37) In some embodiments, the regulation device 25 can comprise a lever 26, the angular position of which can be modified by the user to modify the axial distance between the crushing elements 22, 23. The lever 26 projects frontally from the apparatus 10 in correspondence with a regulation scale 27 on which a numerical sequence is shown, indicative of the particle size of the ground product. In this way, the user can position the lever 26 on the regulation scale 27 exactly in correspondence with the value of the particle size desired. In this way, the crushing elements 22, 23 are disposed with respect to each other at an axial distance which allows to obtain the set particle size value.

(38) During use, the grains fall due to gravity from the containing element 14 toward the grinding device 11, and then enter, after the product has been ground, into a chamber 24 located under the crushing elements 22, 23. From the chamber 24, the ground product then passes into an outlet channel 28 which takes it outside the apparatus 10. The outlet channel 28 can be inclined in such a manner as to direct the ground product toward the collection element 17.

(39) In some embodiments, the drive means 12 comprise an electric motor, known in the art, which is housed inside a main body 15 of the apparatus 10 and is operatively connected to the grinding device 11. In particular, in the embodiment shown, the electric motor is connected to the first crushing element 22.

(40) The apparatus 10 comprises support means 16 configured to support a collection element 17 of the ground product that is independent of the apparatus 10 and is able to interact with a machine for preparing a beverage. The collection element 17 of the ground product can, for example, be a filter-holder element of a known type.

(41) In some embodiments, the support means 16 comprise at least one protruding element 19 which is intended to support the collection element 17.

(42) In the embodiment shown, the support means 16 comprise a pair of protruding elements 19 which project toward the user from a front wall 21 of the main body 15.

(43) The support means 16 comprise weighing means 18 configured to detect a weight of a quantity of ground product delivered by the apparatus 10. It should be noted that the weighing means 18 are configured to detect a net weight of the ground product present on the collection element 17, subtracting from the total weight detected the tare consisting of the weight of the collection element 17 itself.

(44) It should be noted that, as far as ground coffee for espressos is concerned, the apparatus 10 is able to deliver a quantity of coffee provided to prepare a single beverage, or two beverages at the same time, depending on the filter-holder element 17 (single or double) used. It is obvious that, depending on the case, the user sets a desired quantity p.sub.TARGET on the interface 13 which is naturally different depending on the collection element 17 used, that is, whether it is a single filter cup (with only one outlet spout to deliver only one espresso coffee) or double (with two outlet spouts to deliver two espresso coffees simultaneously). In some embodiments, the weighing means 18 comprise a load cell of a known type.

(45) It should be noted that the frequency of the weighing, that is, the cadence of the instants k in correspondence with which the values of instantaneous weight p.sub.k are to be detected, is a function of the weighing means 18, since it is an intrinsic datum of the latter.

(46) The apparatus 10 also comprises a control and management unit 20 which is operatively connected to the weighing means 18 and to the drive means 12 in order to command the latter on the basis of the information received from the weighing means 18.

(47) In some embodiments, the control and management unit 20 is configured as an electronic board comprising a plurality of printed circuits.

(48) In some embodiments, the control and management unit 20 is received in the main body 15, below the drive means 12.

(49) It is obvious that the control and management unit 20 is suitably programmed to implement the method according to the invention described above.

(50) It is clear that modifications and/or additions of parts or steps can be made to the method and/or apparatus as described heretofore, without departing from the field and scope of the present invention.

(51) It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of apparatuses and methods, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.