Method of treatment of grapes by pulsed gas injection

Abstract

A method and a device for air injection into a vinification tank (1) use air injection nozzles (2) installed therein. A rule is applied for automatic variation of injections with time, by a coordinated and combined action of the nozzles, so that for each of the installed nozzles the delivered air jets may be modulated in duration and frequency and combined with the jets delivered by the other nozzles according to a programmable sequence.

Claims

1. A method treatment of grapes in a vinification tank provided with a side wall and a gas injection device, the gas injection device having: nozzles inwardly projecting from the tank side wall, for injecting compressed gas into the vinification tank, one or more control valves for controlling gas flow to the nozzles; the method comprising: independently actuating the one or more control valves, and causing injection of compressed gas in the form of gas pulses injected into the vinification tank through each one of said nozzles, wherein each gas pulse has a duration between a minimum duration of 100 ms and a maximum duration of 15 s.

2. The method according to claim 1, wherein each of said nozzles has a nozzle outlet arranged at an angle of between 115° and 170° with respect to the perpendicular to the side wall, wherein said injection of compressed gas is upwardly directed.

3. The method according to claim 1, wherein said injection of compressed gas in the form of gas pulses comprises a cycle of gas injection through each nozzle, each cycle of gas injection comprising gas pulses through each nozzle.

4. The method according to claim 1, wherein the nozzles comprise three or more nozzles inwardly projecting from the tank side wall, wherein the three or more nozzles are activated in sequence with the three or more nozzles starting respective cycles of gas injection in turn, one after the other.

5. The method according to claim 4, wherein each cycle of gas injection through each nozzle is repeated multiple times per day.

6. The method according to claim 1, wherein the compressed gas has operating pressure ranging from 2 to 7 bar.

7. The method according to claim 1, wherein the method is executed after the steps of: feeding the tank with crushed red grapes, allowing grape skins to separate from liquid to form a compact layer cap above the liquid, and wherein the plurality of injected gas pulses are configured to provide waves in the liquid which break the cap, flooding it with liquid.

8. A method treatment of grapes in a vinification tank with a gas injection device having: at least three nozzles for the injection of compressed gas into the vinification tank, a distribution circuit including control valves for controlling gas flow to each nozzle; the method comprising: inserting grapes into the vinification tank, allowing grape skins to separate from liquid to form a cap above the liquid, independently actuating the control valves and cause injection of compressed gas in the form of gas pulses which are injected into the vinification tank through each one of said at least three nozzles, wherein said injection of compressed gas in the form of gas pulses comprises a cycle of gas injection through each of said at least three nozzles, each cycle of gas injection comprising gas pulses through each nozzle.

9. The method according to claim 8, wherein each gas pulse has a duration between a minimum duration of 100 ms and a maximum duration of 15 s; and wherein the compressed gas has operating pressure ranging from 2 to 7 bar.

10. The method according to claim 8, wherein each cycle of gas injection through each nozzle is repeated multiple times per day.

11. The method according to claim 8, wherein each of said cycles lasts a few tens of seconds to minimize gas consumption.

12. A method treatment of grapes using a vinification tank with a gas injection device having: nozzles for the injection of compressed gas into the vinification tank, a distribution circuit including a separate supply line for each nozzle, control valves on said distribution circuit for controlling gas flow to each nozzle, each of the control valves being present on the respective supply line of each nozzle; wherein the method comprises: actuating the control valves and causing injection of compressed gas in the form of gas pulses which are injected into the vinification tank through each one of said nozzles.

13. The method according to claim 12, wherein the compressed gas has operating pressure ranging from 2 to 7 bar and wherein each air jet has a duration between a minimum duration of 100 ms and a maximum duration of 15 s.

14. The method according to claim 12, wherein said control valves are actuated independently of each other.

15. The method according to claim 12, wherein said injection of compressed gas in the form of gas pulses comprises a cycle of gas injection through each nozzle, each cycle of gas injection comprising a plurality of gas pulses through each nozzle, and wherein each cycle of gas injection through each nozzle is repeated multiple times per day.

16. The method according to claim 12, wherein the nozzles comprise at least three nozzles, which are activated in sequence with the at least three nozzles starting respective cycles of gas injection in turn, one after the other.

17. The method according to claim 12, wherein the nozzles are activated in sequence with the at least three nozzles starting respective cycles of gas injection in turn, one after the other, such that cycles of subsequently activated nozzles are partially overlapping over time; or wherein the nozzles are activated in sequence with the at least three nozzles starting respective cycles of gas injection in turn, one after the other, and wherein cycles of subsequent activated nozzles are not overlapping such that a first cycle of a given nozzle starts a delay time after end of the first cycle of a preceding nozzle.

18. The method according to claim 12, wherein said control valves are actuated such that frequency and duration of the gas pulses emitted by each nozzle, in a same cycle of gas injection, are constant.

19. The method according to claim 12, wherein said control valves are actuated such that the gas pulses emitted by each nozzle in a same cycle of gas injection comprises pulses of increasing duration and/or wherein said control valves are actuated such that the gas pulses emitted by each nozzle in a same cycle of gas injection comprises pause times between consecutive pulses, said pause times presenting increasing duration.

20. The method according to claim 12, further comprising the steps of: feeding the tank with crushed red grapes, allowing grape skins to separate from liquid to form a compact layer cap above the liquid, and wherein the plurality of injected gas pulses are configured to form waves in the liquid which break the cap, flooding it with liquid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the drawings:

[0034] FIGS. 1a and b are schematic sectional and side elevation views of a vinification tank equipped with an air injection device according to a first variant embodiment;

[0035] FIGS. 2a and 2b are schematic sectional and side elevation views of a vinification tank equipped with an air injection device according to a second variant embodiment;

[0036] FIG. 3 shows a detailed lateral sectional view of a side wall of a concrete vinification tank with a nozzle of the air injection device of the invention mounted thereon;

[0037] FIG. 4 shows a side view of a nozzle installed on the outer side of the sidewall of a steel vinification tank;

[0038] FIG. 5 shows a side view of a nozzle installed on the outer side of the sidewall of a steel vinification tank;

[0039] FIGS. 6 and 7 show construction details of a nozzle that can be removed from the outside;

[0040] FIGS. 8 to 13 show graphic examples of time modulation of air injection from the nozzles according to a controlled air injection method of the present invention.

EMBODIMENTS OF THE INVENTION

[0041] Referring now to FIGS. 1a, 1b and 2a, 2b, numeral 1 generally designates a vinification tank having at least three nozzles 2 on its side wall, for injecting air into the liquid mass (must) contained in the tank 1, as will be better explained hereinbelow. FIGS. 1a and 1b show a vinification tank 1 equipped with three air-injection nozzles 2, whereas FIGS. 2a and 2b show a vinification tank 1 equipped with four air-injection nozzles 2.

[0042] The nozzles 2 are equally spaced and placed at a height h from the bottom of the tank 1, which does not exceed one third of the total height of the tank. The nozzles 2 are also connected to a compressed-air generating system 10 of conventional type, only schematically shown, through a compressed-air distribution circuit, generally referenced 3, comprising distinct supply lines for each nozzle, with es 4 installed thereon for control and regulation of the air flow supplied to each of the nozzles 2. Microprocessor means 11 are further provided, which can be programmed to control and regulate, through the valves 4, the air flow injected into the tank 1 through each of the nozzles 2 according to a predetermined program for controlling the modulation of the air jet durations and frequencies and the nozzle operation sequence, as described below.

[0043] As further shown in greater detail in FIG. 6, in the preferred embodiment of the invention, the nozzles are substantially shaped like a wide L and particularly their outlet forms an angle of 110° to 180° with the perpendicular to the side wall of the tank from which the nozzle inwardly projects.

[0044] The optimal angle of the nozzle is selected according to the selected positioning height of the nozzles and their distance from the cap. For example, if the nozzles 2 are installed on the side wall of the tank 1 an angle of divergence ranging from 115° to 170° shall be deemed adequate and an angle ranging from 115° to 150° is preferred. FIG. 3 shows an air injection nozzle 2 mounted to the side wall of a concrete tank. Here, the nozzle 2 is mounted from the inside of the tank by a screw or a snap-fit connection, or another suitable system, at the end of a sleeve 5 embedded in the tank wall and connected in turn, by its outer end, to the air distribution circuit.

[0045] FIG. 4 shows a first way of mounting an air injection nozzle 2 to the side wall of a steel tank. Here, the nozzle is mounted from the outside by fitting it through a sleeve 6 welded within a corresponding hole 7 formed in the wall of the tank 1 and by fixing it to the sleeve 6 by means of an outer connecting ring nut 8.

[0046] FIG. 5 shows a second way of mounting an air injection nozzle 2 to the side wall of a steel tank. Here, the nozzle is mounted from the inside by inserting it into a sleeve 6 welded within a corresponding hole 7 formed in the wall of the tank 1 and by fixing it to the sleeve 6 by means of an inner connecting ring nut 9.

[0047] FIGS. 6 and 7 show the detailed construction of a nozzle 2 with all the parts required for mounting it to a vinification tank 1 from the outside, and particularly the sleeve 6 to be welded into the hole 7 of the tank 1 and the connecting ring nut 8 designed for cooperation with a ring 12 which is rigidly joined to the shaft 2a of the nozzle for fixing the nozzle to the tank wall. Advantageously a cylindrical block, e.g. made of Teflon, may be also provided with an antifouling purpose between the shaft of the nozzle 2 and the sleeve 6, as shown in FIG. 6 and referenced 13.

[0048] According to an important aspect, the present invention provides an original method of injecting air through the above described nozzles 2, which affords optimized disgregration and thorough wetting of the cap.

[0049] The nozzle are sequentially actuated with a modulated delay time between one nozzle and the next. Furthermore, the duration and frequency of the air jets or pulses of each nozzle may be modulated independently of the other nozzles in the tank. Due to the particular combination of the two modulations (duration and frequency on the one side and sequence on the other) a relatively small amount of air can generate shock waves that disgregrate the cap and later cause it to be entirely flooded.

[0050] The sequence modulation and the jet duration and frequency modulation, as well as their combination, may be programmed and modified to obtained various action intensities, such that their effect on the cap may be adapted to the type of grapes and the fermentation stage (pre-fermentation, start, tumultuous, end, etc.).

[0051] Air is injected periodically multiple times a day, with timings selected by the operator as needed and based on his/her experience and for each nozzle, according to the present invention, in cyclic mode, i.e. the nozzles undergo one or more cycles of intermittent jets of programmed duration and frequency and are operated according to a sequence, also programmed, which may involve total alternation of the cycle of one nozzle to that of the previous one, or partial overlapping of the cycles of the two successively operated nozzles.

[0052] The operating pressure of compressed air generally ranges from 2 to 7 bar. The minimum duration of each air jet is 100 ms and its maximum duration is 15 seconds. The following examples, which are given with reference to FIGS. 8 to 13 show a few possible nozzle control modes, although it shall be intended that a number of additional modes may be selected by the skilled person as needed.

EXAMPLE 1

Medium Action

[0053] A medium-intensity air injection action of the nozzles is desired. Referring to FIG. 8, the nozzles are operated to obtain an increasing modulation, i.e. with intermittent jets of increasing duration. Namely, the nozzles are actuated in turn, one after the other. The second nozzle starts a time [RU1-2] after the start of the first nozzle. The third nozzle starts a time [RU2-3] after the start of the second nozzle. Since the second nozzle starts when the first nozzle is still operating, a crossed combination is obtained. Each nozzle is associated with a preset automatic frequency variation (modulation). Here, there is an increasing modulation as both pause times and actuation times increase. In a variant embodiment, only the pause time or the actuation time may be increased. This nozzle control mode generates a rotation moment in the fluid, which amplifies the crumbling effect to the entire cap.

EXAMPLE 2

Mild Action

[0054] A milder-intensity air injection action from nozzles is desired, as compared with the mode as described under Example 1. Referring to FIG. 9, this modulation is identical to the previous one concerning the individual nozzles, but nozzle actuations do not overlap, which means that the next nozzle starts once the previous one has stopped (alternate combination). The effect of this operating mode is, as mentioned above, much milder than that obtained with the operating mode as described under Example 1, but is adequate in certain cases.

EXAMPLE 3

Holding Action

[0055] This nozzle control mode, as shown in FIG. 10 provides constant modulation with constant actuation times and constant pause times for each jet of each nozzle, as well as alternate combinations, with the nozzles never starting together but successively, one after the other. The effect of this operating mode is even milder than that of Example 2, and does not break the cap unless it has already broken by previous actions. It shall be noted that this operating mode is similar to what can be implemented using a prior art device, with the significant, important difference that, in this example, multiple nozzles are actuated in turn, successively one after the other.

EXAMPLE 4

Breaking and Wetting Action

[0056] A combined crumbling and flooding effect on the cap is desired. Referring to FIG. 11, the nozzles are controlled to provide a two-step modulation, which means that each nozzle operates, in a first step, by pulsed injection of jets of constant duration, and in a second step by continuous injection. The nozzles are operated in crossed combination, i.e. the next nozzle starts when the previous nozzle has not stopped its operation yet.

EXAMPLE 5

Cap Submerging Action

[0057] The desired action involves first gas stripping to support the cap and then lowering the cap into the liquid. Here (see chart of FIG. 12), a constant injection mode is provided, with intermittent air jets of constant duration, delivered in turn by each of the installed nozzles. In other words, the time interval between two successive jets of a nozzle is sufficient to cover a jet of each of the other nozzles. Once again this provides a very mild effect, which can only be used for the above mentioned purpose.

EXAMPLE 6

Sustained Medium Action

[0058] This operating mode, as shown in FIG. 13, is similar to that of Example 1, i.e. with increasing modulation and crossed modulation, but is repeated multiple times, here three times.

[0059] Therefore, the various modes may be summarized as follows:

[0060] A) Considering the jet of an individual nozzle:

[0061] 1) Increasing or decreasing modulation—single step: [0062] for an individual nozzle, the duration of actuation pulses and the duration of pause pulses increase or decrease respectively during the nozzle operating time.

[0063] 2) Constant modulation—single step: [0064] for an individual nozzle, both the duration of actuation pulses and the duration of pause pulses remain constant to a preset value throughout the nozzle operating time.

[0065] 3) Increasing-decreasing-constant modulation—two steps: [0066] like the previous cases, but with a continuous air injection of preset duration at the end of each jet of the nozzle.

[0067] B) Considering the sequence of nozzles

[0068] 1) Crossed combination [0069] the next nozzle starts when the previous nozzle has not completed its cycle yet.

[0070] 2) Alternate combination [0071] the next nozzle starts when the previous nozzle has already completed its cycle.

[0072] Each sequence may be performed once or repeated N times (see Example 5 in which the sequence is a succession of single actuations of each nozzle and this sequence is repeated 5 times, or Example 6, which is the same modulation as in Example 1, with repetition=3)

[0073] It shall be noted that each of the above examples is obviously a “punch down”. Such punch down may be repeated N times a day.

[0074] The above disclosure clearly shows that the method of the present invention can fulfill the intended objects. Particularly, the various possible applications of a predetermined jet modulation rule for each nozzle and sequential nozzle combinations provide disgregrating waves which submerge and break the entire cap, thereby flooding it with liquid. This occurs within a few seconds and with no violent action.

[0075] Due to a high extraction potential and action times as short as a few seconds, the consumption of air or inert gas is minimized, and the problems associated with flavor- and alcohol-stripping are hence considerably reduced.

[0076] The modulated-sequential control mode has been also experimentally found to be effective even when nozzles are installed from the bottom, when this creates no hindrance (self-emptying slant-bottom tanks), thereby obviating the problems of similar prior art air-bubble systems.

[0077] Therefore, when allowed by the tank emptying and cleaning conditions, the nozzles may be also mounted to the bottom of the tank and vertically extend therefrom. In this case, they may extend in linear fashion, which means that the angle of divergence of the substantially L shape of the nozzles is 180°. Yet, nozzle control modes and air injection modulation are as defined by the above described and illustrated inventive method.

[0078] It shall be finally noted that, while reference has been always made herein to air as the fluid in use, any fluid that is functionally equivalent to air, e.g. an inert gas such as nitrogen, may be alternatively used, and in this sense the term air shall be intended, each time it is mentioned.

[0079] Variants and/or changes may be made to the method of controlled air injection into a vinification tank and to the associated device of the present invention, without departure from the scope of the invention, as defined in the following claims.