IT202000006892A1 - Method and apparatus for de-stemming and qualitative fractionation of hand-picked grapes - Google Patents

Description

Method and apparatus for de-stemming and qualitative fractionation of grapes from hand-picked grapes

Technical sector of the invention

The present invention is placed in the agri-food sector, and has as its object in particular a method and a relative apparatus to be used for the production of wine in a phase immediately after the harvest of the bunches, a phase which consists in separating the berries from the stalk and fractioning ( divide) the grapes into different ripening classes.

Background of the invention

When do hand-picked grapes arrive in the cellar for alcoholic fermentation? it is now normal practice that the berries are separated from the stalks through a de-stemming process. To produce wine,? it is desirable to have only berries in good condition. Impurity such as stalks, green, rotten or sunburned berries or the presence of other foreign objects can have a negative influence on the wine. Moreover, not all grapes have the same level of ripeness, sometimes there are important differences both between bunches and between grapes within the bunch itself. Berries with different ripening state evidently have potential? of production of strongly different wines [1].

The machines used to separate the grapes from the stalks are called destemmers. Often in front of the cellar there are also manual and mechanical cleaning and sorting systems for the bunches.

The goal of post-harvest grape sorting systems? to eliminate all extraneous elements, defined with the acronym MOG (Material Other than Grapes), such as plant residues, (petioles, leaf edges, pieces of stalks), and in the sorting operations the grapes are also eliminated (berries, clusters or fractions of clusters) in non-optimal conditions, due to the presence of rot or due to the state of ripeness considered not sufficient. Sorting systems are divided into two main categories: manual sorting belts, which require the presence of operators who carry out the selection, and automatic sorting systems, which on the contrary? using different principles? they mechanically separate the foreign parts or select the grapes on the basis of their quality.

The first systems are placed upstream or downstream of the destemmer and can be used in the final cleaning of the grapes harvested by hand or by machine, while the automatic systems are generally applied downstream of the destemmer and are more? used in the qualitative selection of hand-picked and de-stemmed grapes or those harvested by machine.

The known automatic sorting devices exploit different principles, from the separation action by air jets at a certain pressure (thanks to the different weight of berries and vegetable residues), to systems that exploit the different density. of the parts to be separated, up to the color in the optical sorting systems pi? advanced [2].

Among the devices more? simple include vibrating selection tables equipped with draining grids and sieves for the recovery of whole berries. For example, the device known as? Mistral? Belongs to this first group of devices, historically produced by the French company Vaucher-Beguet (now PMH vinicole - https://www.pmh-vinicole.fr), where a vibrating screen allows the elimination of larger waste elements, while the larger pieces? small ones that pass the screen are removed from the grapes with a blade of compressed air of variable thickness and length, which blows on the berries as they fall into the receiving tank at the end of the carpet.

As mentioned, more sorting devices? recently conceived are based on optical selection, equipped with optical sensors and able to select elements with characteristics visually different from those of healthy and ripe grapes.

One of the latter devices? for example the device? X-Tri? of the Protec company (https://www.pmh-vinicole.fr). These systems include a destemmer, a vibrating distribution and acceleration table and two viewing areas, one equipped with two optical chambers placed on the belt, which recognize the green parts and immature grapes (pink) and one with a chamber placed at the end of the tape and set to recognize dry material (dried berries and leaves and insects). The units optics are able to work in the visible and infrared. The removal of the foreign elements identified takes place with a jet of air that selectively removes them from the rest of the grapes.

Both manual selection and mechanical selection with an optical recognition system produce a waste that as such does not enter the fermentation process.

The densimetric system, on the other hand, separates the grape population into two fractions, producing two different musts which will give rise to the corresponding two wines with distinct chemical and sensorial characteristics.

A system characterized by a certain complexity? ? the selection and sorting system? Tribaie? of Amos Industries (https://www.amos-industrie.com). In addition to the separation and cleaning of the grapes from foreign bodies, this apparatus? able to select, separating them into different quality classes, grapes with different ripening characteristics. The separation of the green parts takes place on a first series of vibrating carpets and perforated screens that accompany the grapes to a toothed roller, which holds the green parts (leaf edges, pieces of stalks, petioles), and to a carpet on which the grapes undergo a first selection of whole and consistent grapes of quality? greater, which are separated from the broken and soft ones that adhere to the surface and are removed. The quality grapes higher are then selected on the basis of their density? in a bath full of wort or a sugar solution of density? note: the berries with density? lower than that of the liquid will rise to the surface and will be separated by skimming from those pi? concentrated, which are arranged instead more? down.

Based on the above, can? say present to the insiders the desirability? of a system that allows, as well as in general the removal of unwanted elements such as stalks and other extraneous elements, the separation of the berries in pi? classes, each of homogeneous and different maturation, capable of producing wines of different characteristics, with evident qualitative advantages (through the recomposition of wines with special blends) or of widening and diversification of the offer by the winery. However, for how long? to the knowledge of the applicant, no known technical means? able to achieve this objective in an effective way and that does not resort to complex solutions with high or even prohibitive costs (production and management).

The purpose of the present invention? therefore that of providing an? equipment and a method that allow an automatic separation of the berries such as the one to which one? just mentioned, with simplified and relatively cheap structural and functional solutions, at the same time guaranteeing a good homogeneity? the degree of ripeness of the berries in the same class subject to separation.

Summary of the invention

This object is achieved by the method and apparatus for qualitative destemming and fractionation of grapes for grapes harvested by hand according to the invention, the essential characteristics of which are the subject of the respective attached independent claims.

The basic aspect of the invention lies in the idea of splitting into two or more? the berries leave at the entrance to the cellar, exploiting the different resistance to detachment from the stalk that they offer according to the degree of ripeness. By transferring a first determined and commensurate quantity to the grapes? of mechanical energy, this will be? able to cause the detachment of only (or at least in great prevalence) grapes of a certain degree of ripeness interval. The grapes that are less ripe, and therefore tend not to be susceptible to detachment due to the effect of the first quantity? of energy, can be detached through the subsequent application of a second and commensurate (greater than the first) quantity? of energy, and so on. Using this principle? It is possible to obtain in a relatively simple way, and with a reduced cost system (significantly lower than for example densimetric systems) at least two grape fractions with different ripeness, to meet the requirements of having different products (wines) and manage in a more? effective quality. The obtaining of three or more? grape fractions with different characteristics? in particular a peculiarity? obtainable with the present invention and in fact not present in the systems on the market today. Ultimately, the production of (at least two) different musts starting from the same mass of hand-picked grapes obviously allows the production of different wines. This ? extremely useful for wineries, to then be able to manage the quality level of the blend and the desired oenological targets through subsequent blends between wines.

Brief description of the drawings

The characteristics and advantages of the method and apparatus for de-stemming and qualitative fractionation of the grapes for hand-picked grapes according to the invention will be more evident. clearly from the following description of its embodiments, made by way of non-limiting example with reference to the attached drawing in which:

- figure 1? a graph showing the average refractive index of fractionated grapes according to the invention;

- Figures 2 to 4 are schematic representations of possible plant configurations for a practical implementation of the method according to the invention.

Detailed description of the invention

As anticipated, the present invention starts from the observation of inhomogeneity? of the grapes entering the winemaking process. Such inhomogeneity? it is found at the average mass level of the berries and the relative forces of detachment from the stalk. ? also and also observable that the mass tends to increase as a function of the accumulation of sugars, therefore berries more? ripe contain greater quantities? of sugar and have larger masses. At the same time, the detachment force of the berries decreases during ripening as a consequence of the normal physiological mechanism that determines the collapse of the cellular structures of the pedicel that connect the berries to the stalk. The extreme variability? of ripening of the grapes? after all verifiable both within the same vineyard, therefore a variability? spatial, that between contiguous plants, between clusters on the same plant, up to the different level of ripeness that the berries show within the single cluster. So there is a relationship between accelerations impressed by the destemming apparatus and the quantity? of berries that detach from the stalk.

According to the invention, the link between the state of ripeness of the berries, mass and detachment force is therefore exploited to propose a system for separating the berries from the bunch capable of applying, to the bunch itself or more? properly to the mass of clusters treated, successive stages of application of mechanical energy having entity / intensity? increasing, in such a way as to be able to divide the mass into at least two portions characterized by different levels of ripeness. The principle? therefore that of applying forces to intensity? different and growing to the clusters to select the grapes with different ripeness levels. An exemplary implementation solution of this principle can? provide an equipment module that can be traced back to a known type of horizontal axis destemmer, although, as will be seen? pi? forward, appropriately modified and / or coordinated in pi? modules suitably configured to be able to generate at least two fractions of grapes with different ripeness.

Returning to the main methodological aspect of the invention, the relationship between detached berries and force applied to the bunch can? be derived and modeled relatively precisely. Experiments carried out by the present inventors have confirmed that the berries more? mature require less forces of detachment while those less mature more? high with an inverse correlation. For example, three batches of 150 kg of grapes each were treated (mainly Trebbiano, harvested by hand), de-stemmed with a traditional destemmer, which, as known, provides for a rotating shaft in charge of beating the bunches. Proof ? was carried out at two speeds: one low and one high, the latter corresponding to that of normal use of the destemmer. The reduction in speed? rotation of the shaft? was obtained through the use of an inverter which made it possible to reduce the frequency of the power supply current of the destemmer. The speed? rotation of the shaft? been lowered up to 80 rpm, compared to the 360 rpm at which the machine works normally and with which a detachment is obtained almost? total of the grapes from the stalks. The test at 80 rpm instead allowed a partial detachment of the berries from the stalks (about 45%). Therefore, of the berries obtained from the 80 rpm test? It was possible to measure the refractive index of the detached fraction and that of the fraction still attached to the stalk. The measure of the refractive index? was chosen why? ? a parameter commonly used in viticulture to measure the sugar concentration in grapes. The comparison between the refractive indices of the two fractions? shown in the graph of figure 1, where L? the average refractive index of the part of berries removed at speed? ? slow? (as mentioned 80 rpm) and Ls that of the remaining fraction (average of the results on the three batches, the error bars represent the standard deviation).

The sugar concentration of the L fraction? found to be significantly higher than that of the Ls fraction. The must selected at speed? slow had a sugar concentration of 150 g / L, while the other one of 120 g / L. Still? in the case of rather low sugar concentrations (the grapes used in the tests were not very ripe), there is a difference of 30 g / L of sugar between the musts, a decidedly significant difference from an oenological point of view, which confirms the effectiveness of the principle followed. In practice, the wines that can be produced from these two musts would have almost two alcoholic degrees of difference, obviously making them very different.

Still in the context of fractionation by means of a beater shaft, rotating within a perforated cylinder coaxial to the shaft (and fixed or in turn rotating), the shaft carries beater arms that extend radially in a distribution whose attachment points to the shaft follows a helical path. Such a configuration? similar to that of a screw conveyor, performing (also) the function of sliding and subsequent unloading of the stalks. At the end? of the arms are mounted paddles, in rubber or stainless steel.

In this type of machine the separation of the grapes? obtained by the mechanical action of the beater shaft in combined action with the perforated cylinder (or tumbler), according to a mixed operation:

- application of a centrifugal force determined by the rotational motion imparted to the grapes;

- application of a shear force between the terminal part of the arms mounted on the beater shaft and the perforated wall;

- application of an impact force between the beater arms and the bunches, and between the perforated wall (sifter) and the bunches.

All three mechanical actions just described are related to the speed? rotation of the beater shaft, according to the geometry of the machine (diameter and length of the rotating drum, arrangement and shape of the beater arms, number, size and shape of the holes on the cylinder wall).

In the first instance, can you? focus attention on the first mechanical action listed above, that is the application of a centrifugal force to the grapes. As bodies endowed with a certain mass, during the rotation the berries are subjected to a centrifugal force F proportional to their mass m, squared of the velocity? angular? and to the radius of rotation r, according to the relation:

F = m ?? <2>? R

Tendentially, the detachment of the grape will take place? when the centrifugal force will exceed? the force of detachment from the stem. This ? therefore the basis for a possible modeling to establish the quantity? of desired energy, acting on the input parameters, useful to cause the fractionation of a class of grapes of a certain ripening field. Pi? precisely, in the present case, the equation that governs productivity? hourly of machines such as those taken as reference puts in relation the hourly flow, through some coefficients, with the area of the drum section and the speed? linear displacement of the moving mass (proportional to the pitch and angular speed of rotation). Therefore, once a certain flow rate has been set, by solving the equation for the diameter of the transfer element, that is the rotating drum, and leaving it free to vary the speed? angle of the beater organ,? Is it possible to determine the values of the diameter of the drum capable of ensuring the achievement of the set flow rate as a function of varying levels of speed? of rotation. At the same time, for each pair of values? Velocity? angular-diameter of rotation? cos? determined,? It is possible to calculate the corresponding centrifugal acceleration.

? It is therefore possible to hypothesize, once a work capacity deemed appropriate for the machine has been established, of the speed couples? of rotation and diameter of the cylinder such as to keep the flow rate constant and at the same time supply different energies to the incoming bunches suitable for detaching grapes with different ripeness, forming the various desired fractions.

With reference now to figures 2 to 4, some machine diagrams are proposed, always referable to the general architecture described above, suitable for dividing two types of grapes (but on the basis of the same scheme, three or more types can obviously be divided. ) using respective shaft and cylinder sections in series. The diagrams are in fact self explanatory for the expert in the field who is well acquainted with the architecture of traditional destemmers. Obviously the procedure can? however lend itself to being developed with machinery of a different nature, and in particular making use of means / systems for handling the bunches of different nature, for example with reciprocating motion instead of moving the bunches. rotary.

In all three examples there are two sections arranged coaxially and in series (the axis corresponding to the X direction of advancement of the material, that is, of the clusters), comprising the following components, distinguished in the different machines by the same reference indices shown here :

1 beater shaft first section;

2 second section beater shaft;

3 drum or rotating cylinder first section;

4 drum or rotating cylinder second section;

51 first electric motor with inverter, driving the first shaft;

52 second electric motor with inverter, driving the second shaft;

6 grape loading hopper;

7 feeding screw;

81 first pump to feed the fermenters of the de-stemmed grapes in the first section;

82 second feeding pump towards the fermenters of the destemmed grapes in the second section;

91 first device for control system in feedback on the destemmed flow rate in the first section;

92 second device for feedback control system on destemmed flow in the second section;

D1 first section cylinder diameter

D2 second section cylinder diameter

R unloading stalks;

And entry of grapes (bunches);

F1 exit of de-stemmed grapes in the first section (first fraction);

F2 destemmed grapes exit in the second section (second fraction).

Each section, like a traditional destemmer, has the mere function of separating the grapes from the stalks, but? It is evident that by making two (or more?) sections with different structural and dynamic characteristics cooperate in series, the separation operates in a different way on the two (or more?) sections, allowing to selectively detach the berries and collect them separately in fractions and according to the different degree of ripeness. These different characteristics that differentiate the sections may in particular include, individually or in combination: i) the speed? rotation of the shaft, which the appropriate control means are configured to control in a different way between the sections and in at least one of the two sections significantly lower than the minimum of the destemmers currently available on the market; ii) different shaft-cylinder geometry between the sections (diameter and axial length of the cylinder), also and above all with the function of applying the correct retention time of the bunches in correspondence with the velocities? necessary for the desired fractionation (number of fractions and percentage distribution among the different fractions according to the oenological needs of the company). In addition to these main parameters / characteristics, other variations can be envisaged, such as the pitch of the propellers with which the beater arms are arranged, the inclination of the beater shaft and others.

? furthermore, advantageously, a functionality should be provided in the control system? electronic feedback control system (comprising devices 91, 92 which can for example include load cells arranged in correspondence with the destemmed recovery containers which continuously measure the weight and indirectly the flow rates of the grapes leaving the different fractions) to manage the distribution of the grape masses in the percentages determined by the oenological choices. The system ? in practice configured to adjust the speeds? of the first and second sections as a function of the obtainable and / or desired relative proportion between the two separate fractions. This control and adaptation in real time? very important so that? the machine (or set of machines, as explained below) possesses the capacity? to adapt to work and to divide different types of incoming grapes which presumably will require different energies depending on the cultivar, the production areas, the degree of ripeness, the form of farming, etc.

The three examples shown implement these technical concepts in respective integrated equipment, it being understood that they can be equivalently put into practice by assigning the tasks of the different sections to respective machine modules physically separated from each other, which will each have the same aspect. of a known destemmer, but with specific and coordinated project parameters.

As a first approximation, higher speeds? of rotation, therefore greater accelerations, imply:

- greater centrifugal force;

- increase in the driving torque of the beater shaft up to the maximum torque point of the electric motor used, therefore greater cutting force at the beater-wall interface of the cylinder;

- greater impact force between the beater arms and the bunches, again as a function of the greater drive torque.

So, if the section or the machine is moved by an electric motor suitably sized in terms of torque, power and number of revolutions, use speed? of rotation pi? high involves the application of a greater quantity? of mechanical energy to the unit? mass being processed, then to the individual berries. Since necessarily the berries are more? mature to have a tendency to the pi? easy posting,? It is clear that the energies transmitted must be increasing in the passage from one section / machine to the next. The first section / machine, at pi? low mechanical energy, separer? the berries more? easily separable or more? mature, the second section those pi? difficult to separate, that is the less ripe grapes, and so on.

Going into further detail on the three hypotheses of the illustrated examples, in the case of figure 2 the two sections have the same diameters of the cylinder D1, D2 between the two sections (for example about 0.5 m), but differ in speed? of rotation of the shaft established in this case through the respective motors 51, 52 in 100rpm and 400rpm respectively. From these parameters derive different centrifugal accelerations between the two sections, estimated respectively in about 20 m / s <2> and 400 m / s <2>.

The example of figure 3 instead foresees two sections of increasing diameter (D1 of about 0,5 m and D2 of about 0,65 m), with speed? shaft rotation of 100rpm and 340rpm respectively in the first and second section. The resulting centrifugal acceleration? also estimated here in about 20 m / s <2> and 400 m / s <2>.

Finally, the example of figure 4 shows a first section with a larger diameter (D1 of about 0.5m) followed by a second section with a smaller diameter (D2 = 0.35m). The speeds rotation of the shaft are increasing between 100rpm (first section) and 450rpm (second section), still obtaining centrifugal acceleration values congruent with those of the previous examples.

It is therefore noted that the result of increasing the mechanical energy transmitted between one section and the next or consecutive one, in respective stages, can be obtained by acting in a coordinated way on different parameters and in a different way; the numerical values indicated above must obviously be considered merely as an example useful for understanding the implementation criterion with which the methodological principle according to the invention can? find a practical realization.

Based on the above? It is clear that the present invention achieves the intended purpose of obtaining, with a system at a lower cost than those currently on the market, a fractionation of the berries capable of producing (at least two) different musts starting from the same mass of hand-picked grapes . Different wines are produced from different musts. This ? extremely useful to wineries, to then be able to manage the quality level of the labels in the different vintages through the successive cuts between the wines.

The grapes produced within the same vineyard present a wide heterogeneity? in terms of sugar content, acidity, maturity? phenolic, etc. These differences are found between the clusters but also within the same cluster with grapes that have different levels of ripeness and therefore potential. very different oenological results in the wines produced. In fact, in recent years, for the production of quality wine, the selection systems of the grapes entering the winemaking process have multiplied, which mainly include manual sorting systems (where the operators watching choose the bunches) and mechanical systems based on mainly optical or densimetric technologies. The problem with these systems lies either in their limited effectiveness (manual sorting) or in the high investment costs that are sustainable only for companies with large production areas and capable of amortizing this investment. Furthermore, some of these systems (manual and optical sorting) consider as? Selection? exclusively the removal of immature or damaged grapes or clusters and therefore considered unsuitable for winemaking. Others like the densimetric sorting return two or more? different fractions from which to produce more? wines. ? therefore it is evident that in the face of a particularly felt need, the present invention provides a particularly advantageous solution, through a simple and economical system that can? return fractions of grapes of different quality? able to support many small realities? productive that often make of the quality? their distinctive element is that they cannot afford the expense of purchasing an optical or densimetric sorter (which can be estimated to be about an order of magnitude higher than that of a machine according to the present invention).

Furthermore, the system according to the invention does not add but replaces a machine (the destemmer) which? however essential for the winemaking process from hand-picked grapes, introducing a further functionality? given by the qualitative fractionation system of the berries, in addition to the separation of the berries from the stalks.

The present invention? It has been described heretofore with reference to its preferred embodiments. ? it is to be understood that other embodiments may exist which pertain to the same inventive core, all falling within the scope of the claims set forth below.

Claims (1)

CLAIMS 1? A procedure for automatically splitting the berries of a mass of bunches of hand-picked grapes into two or more? fractions of berries attributable to respective different levels of ripeness, the procedure providing for subjecting said mass to two or more? consecutive stages of application of mechanical energy, the quantities? of energy applied in the two or more? stages being progressively increasing and commensurate each to induce the detachment from the stalks and the collection of respective of said two or more? fractions of berries. 2 ? The process according to claim 1, wherein the quantities? of mechanical energy transmitted in the respective stages are controlled in feedback on the basis of quantitative measurements of the detached berries stage by stage. 3- The process according to claim 1 or 2, in which the mechanical energy is applied by means of a rotating beater inside a cylinder inside which said mass of bunches of grapes is fed in axial advancement, said mechanical energy being controlled by varying at least the speed? rotation of said beater from one stage to another. 4 - The process according to claim 3, in which the mechanical energy is controlled by also varying at least the diameter and / or the length of said cylinder between one stage and the other. 5? An apparatus for automatically splitting the berries of a mass of bunches of hand-picked grapes into two or more? fractions of berries with respective different levels of ripeness, including two or more? modules or sections in series along a direction (X) of advancement of said mass of clusters, said modules or sections providing means (1, 2, 51, 52) for handling the clusters, independently controlled, suitable for applying energy mechanics to said clusters, the apparatus further comprising control means configured to control said handling means so that quantity? of mechanical energy applied in the two or more? modules or sections are progressively increasing and commensurate each to induce the detachment from the stalks and the collection of respective of said two or more? fractions of berries. 6 - The apparatus according to claim 5, wherein said control means are configured to control in retraction said retraction movement means on the basis of signals emitted by means (91, 92) for quantitative detection of the detached berries in each of said two or more? modules or sections. 7? The apparatus according to claim 6, wherein said quantitative detection means (91, 92) comprise load cells suitable for detecting the weight of the berries detached in respective modules or sections. 8? The apparatus according to any one of claims 5 to 7, in for each of said modules or sections said movement means comprise a beater (1, 2) rotating within a cylinder (3, 4), arranged coaxially along said direction (X ) of advancing the mass of clusters, said control means being configured to control the speed? rotation of the rotating beaters (1, 2) of said modules or sections so that the speed? rotation is progressively increasing between a module or section and the next module or section of the series. 9? The apparatus according to claim 8, wherein the cylinders (3, 4) of said modules or sections have different diameters between a module or section and the next module or section of the series. 10? The apparatus according to claim 8 or 9, comprising two or more? sections integrated in series with respective outlets (F1, F2) for said fractions of berries and provided with respective motors (51, 52) for the independent feeding of the relative rotating beaters (1, 2).