A fermenter for fermenting a solution, comprising: a vat (2) predisposed for containing a solution (3) to be fermented, and provided with an inlet opening (4, 33) and an outlet opening (5, 25); a pumping-over conduit (100) provided with a first connection (101), which is placed in communication with a lower zone of the vat (2), and a dispensing opening (103), disposed in an upper zone of the vat (2) so as to be capable of dispensing a liquid above the upper level of the solution (3). The pumping-over conduit (100) comprises a second connection (102), disposed in an intermediate position between the first connection (101) and the dispensing opening (103), which dispensing opening (103) is so arranged as to allow the gas to be introduced into the pumping-over conduit (100).

The present invention relates to an improved fermenter, used in particular in the wine industry for vinification of musts, and also useful on closed tanks, i.e. pressurised, such as autoclaves.

The prior art includes very many types of fermenters, which all substantially comprise at lease a recipient, or vat, with various types of bottoms, often an inverted truncated cone, provided with an opening for introduction of liquid to be fermented and a tap for discharging the fermented liquid.

The liquid to be fermented is, in the case of vinification, i.e. the production of wine from crushed grapes, made up of wine juice and also marc, i.e. by the whole of the solid parts of the grapes constituted by skins, grape seeds (seeds present in the grapes), and also possibly by stalks. The fermented liquid is more properly termed fermented must or wine.

During the process of fermentation, in the upper part of the vat a solid floating layer is formed, known as the cap, constituted by various layers of marc, a topmost of which layers usually is slightly raised on the top of the liquid. This is a particularly compact mass which it is appropriate to break so as to prevent, on completion of the fermentation, its becoming excessively solid, but also so as to exploit its characteristics during the course of maceration of the fermenting liquid.

The skins, for example, contain substances that colour the wine, and this characteristic assumes relevance in particular for grapes that yield the extractive colorant substances with less readiness, such as for example Sangiovese grapes. To achieve a correct use of the cap it is therefore important for it not to be left simply to float on the liquid to be fermented but for it indeed to be used so as to improve the quality of the wine.

For this purpose fermentation recipients are known which enable carrying out, during the course of alcoholic fermentation, a complete and calibrated movement of the marc so as to improve its yielding of colorant and polyphenolic substances.

Often the techniques used at present are expensive and complex and the action thereof on the cap of must is aggressive and leads to a formation of an undesired quantity of dregs.

One of the habitually-used techniques includes a pumping-over which is operated using various devices whose ultimate purpose is to sprinkle the must contained in the vat onto the cap, in the form of a shower.

However, this solution also requires, for its application, a presence of pumps and piping that make it expensive and subject to halts in operations due to possible failure or malfunctioning. Further the pumps lead, in the case of dragging grape seeds and skins, to an increase in the presence of dregs, which facilitates irreversible dissolving of substances characterised by astringent properties and bitter flavours in the wine.

It is in fact known to act on the cap using pneumatic pistons so as to immerse the cap in the must-wine, even only partially, in order to break it and reduce its solidity. This operation, known as punching down, is repeated two or three times a day and requires special attention as each punching-down causes lacerations in the marc and thus increases the formation of dregs.

There also exists a punching-down by injection of only compressed air using lances or the like, for moving and stirring the cap. When this operation is done manually it is necessary for the personnel to be instructed in advance so that the operation is carried out at a predetermined velocity. Excessive injection of air would cause significant alcohol loss, or in some cases, would facilitate an acetic acid fermentation that would transform the wine into vinegar. Contrarily, the injection of too-little air would uselessly slow down fermentation.

Considering that a vat can contain up to 3.000-4.000 hl., it is easy to understand the importance and delicacy of these operations. A possible error in evaluation during the punching-down might lead to the loss of a significant quantity of wine.

All the known-type solutions illustrated in the foregoing have in common the fact that they act mechanically on the cap, mostly after the cap has already been formed and has reached a certain degree of solidity. Further, the mechanical action on the cap facilitates the breaking-up of the marc and causes an undesired increase in the quantity of dregs produced. As is known, the dregs can be the cause of undesired flavours and can require further operations for the following cleaning of the wine.

Alternatively to the use of compressed air, inert gases have also been used such as nitrogen, carbon dioxide and the like. These solutions include the injection of pressurised gas (normally from 3 to 7 bar) from the bottom or the walls of the tank, through two or more conduits with the purpose of striking the floating cap on the surface, and attempting to inundate it and break it up.

The aim of the present invention is to obviate the above-described drawbacks manifested by the known-type devices by providing a fermenter which does not require motorised mechanical devices for moving the marc.

A further aim is to improve the exploitation of the marc while at the same time reducing the number of operations otherwise requested for it.

Further, an aim of the present invention is to reduce the number of mechanical devices present in the fermenters, so as to reduce the costs both of realisation and management thereof. In this way it is possible further to reduce the number of failures that can occur during the fermentation steps.

Lastly, a further aim is to make the fermenter easier to use.

With particular reference to appendedFIG. 1, reference numeral1denotes a fermenter in its entirety.

The fermenter1comprises in particular a vat2provided with a bottom8in which the solution3to be fermented is contained, constituted in the example illustrated herein by wine, wine must, marc and any chemical additives, yeasts or the like. The vat2further exhibits an opening for introducing the solution3to be fermented, i.e. crushed grapes, and an opening5for collecting the fermented solution6, i.e. wine. For example, the introduction of the crushed grapes can be done through an opening (33) located at the top of the vat2.

The vat2can be provided with a upturned truncated cone bottom for facilitating extraction, on completion of fermentation, of solid residues, i.e. the dregs30, of the marc and grape seeds34An outlet opening25is therefore located at the bottom8, by means of which it is possible to access the bottom8not only for the removal of the dregs30and the marc but if required also for facilitating access internally of the vat2for the operations of maintenance and cleaning.

In an alternative embodiment, illustrated inFIG. 11, the vat2might be a closed tank, for example an autoclave of the type that can be used for production of fizzy and sparkling wine. As is known, an internal pressure is determined in the vats, determined by the development of fermentation gases. In the production of fizzy and sparkling wines the cap10of marc might not be present. In the production of red wines the cap10is, on the other hand, present.

In an alternative embodiment, illustrated inFIG. 13, the vat2might still be a closed tank, and therefore characterised by the presence of an internal pressure determined by the development of fermentation gas, in which the accumulation means7are constituted by the vat2.

The fermenter further comprises a pumping-over conduit100, provided with a dispenser103substantially located at the top33of the vat2in such a way as to be able to spray with liquid the cap of marc10which forms on the liquid surface of the fermenting solution6. The pumping-over conduit100is placed in communication with the bottom zone of the vat2, by means of a first connection101. Alternatively the pumping-over conduit100might be located internally of the vat2with a lower end thereof arranged in the bottom zone of the vat2. In both cases the first connection101, which in the case of the internal pumping-over conduit100, is constituted by the lower end of the conduit100, can be provided with a control valve V1for controlling opening and closing thereof.

In both embodiments the pumping-over conduit100is filled with solution, in particular the solution3present in the bottom zone of the vat2, up to a level that substantially coincides with the level of liquid internally of the vat2, including the height of the cap10. In other terms the pumping-over conduit100fills with solution up to the level reached by the cap10, by virtue of the communicating vessels principle.

The pumping-over conduit100is advantageously provided with a second connection102, having variable shape and dimensions, located between the first connection101and the dispenser103. The second connection102is predisposed for enabling introduction of a gas internally of the pumping-over conduit100. The introduced gas has a lower specific weight with respect to that of the solution contained in the pumping-over conduit100at the second connection102, and this determines a vigorous thrust in an upwards direction of the column of solution overlying the conjoining point between the pumping-over conduit100and the connection tube102, so that the solution exits the dispenser103and sprays the cap10. The second connection102too can be provided with a control valve V2, predisposed for controlling the opening and closing thereof.

The fermenter provided with the pumping-over conduit100structured as described in the foregoing therefore enables carrying out the re-mounting of the solution to be fermented without the aid of pumps or other mechanical organs. In this way the general costs are reduced and there is no need to subject the solution to be fermented to mechanical actions that might cause it to deteriorate and might compromise the quality thereof.

In a particularly advantageous embodiment the vat2is internally provided with a membrane7for accumulation of fermentation gas which extends from the walls35towards the inside of the vat2and which is solidly constrained to the internal walls35of the vat2. The membrane7is conformed in such a way as to form, between the walls35of the vat2and the lower part of the membrane7, a concave surface able to trap the small bubbles of gas11.

In the example illustrated inFIG. 1, the surface is a truncated cone-shaped inverted inclined surface14in the form of a truncated cone, the external edge26of which is solidly constrained to the internal surface of the circular vat2.

Obviously, if it is desired to apply the membrane to vats having a non-circular transversal section, for example square, the membrane will have to exhibit a surface suitable for the aim, i.e. a truncated pyramid shape.

Therefore an opening20remains open in the central zone of the vat2, which opening20is not involved by the membrane7. The small gas bubbles11can rise through this opening20without being intercepted by the gas accumulation membrane7.

The small bubbles of gas11which rise along the perimeter area of the vat2are intercepted by a chamber27that is open in a downwards direction, formed by the concave surface afforded between the lateral walls of the vat2and the lower surface of the membrane7. The small bubbles of gas11, by accumulating in the chamber27, slowly saturate the free volume up to forming one or more large bubbles36which then unite one by one to form larger bubbles12generated by the bubble36which, after having grown beyond the free dimensions of the chamber27, overruns from the internal edges in the zone of the opening20.

In this way the small bubbles of gas11form, as they rise towards the surface, bubbles12of larger dimensions able to continuously move a cap10formed by the marc contained in the vat2. The cap10is then continuously aerated from below (by the carbon dioxide of the bubbles12) and the lower part thereof, in contact with the surface of the must-wine6, is stirred and newly immersed in the must-wine6, facilitating the yielding-up of substances, including colorants, contained in the cap10. This yielding involves the whole surface of the cap10as its continuous stirring prevents solidification thereof.

As the cap10does not normally reach the state of solidification, its removal, on completion of fermentation, can also be carried out simply by acting from the outlet opening25, in the same way as for the dregs30and the grape seeds34.

With the action of the large bubbles12during the rising thereof in the must-wine6, stirring of the fermenting liquid3is also facilitated.

In this embodiment the second connection102of the pumping-over conduit100opens below the membrane7, substantially in the chamber27. In this way it is the gas, produced by the fermentation and trapped in the chamber27, which thrusts the column of liquid present upwards above the second connection102in the pumping-over conduit100. The start and stop of the pumping-over can be determined through the opening and the closing of the control valve V2. The presence of the membrane7thus enables carrying out the pumping-over without any need to use external gases; in this way a further costs saving is made and the natural energy represented by the carbon dioxide generated during the alcoholic fermentation can be exploited.

In the case of a closed tank in the embodiment ofFIG. 11, the use of the accumulated gas for carrying out the pumping-over facilitates the dragging of the yeasts, which by force of gravity tend to settle on the bottom, returning them to the upper part of the tank and making the use of mechanical stirrers no longer necessary. Further, the homogenisation of the product and the temperature thereof are facilitated.

Alternatively the accumulated gas might be temporarily stocked in appropriate volumes or storage areas external of the fermenter. In this case the second connection102would be in communication with the external storage volumes external of the fermenter.

The fermenter can further be provided with a bypass conduit28which places the chamber27in communication with the part of the vat2that is above the membrane7. This conduit28, which can be provided with a commandable closing valve29, can be used for sending the gas to the cap10zone overlying the membrane7, facilitating the stirring thereof.

In a possible further embodiment of the fermenter, illustrated inFIG. 7, the second connection102of the pumping-over conduit100is in communication with the bypass conduit28

In order to possibly influence the fermentation from outside, it is possible to inject external gases, or the internal gases that have been stored in the external accumulation volumes, into the fermenter. The injection of the gases from the outside can be controlled by means of a control valve V3. The control valve V3, for example, can be connected to the bypass conduit28or to the second connection102.

Via the bypass conduit28or the second connection102and/or taps16or other like conduits, it is also possible to place in communication two or more fermenters between them in order to exploit, for example, the gas (CO2) produced in excess in one of them in order to supply others. This operation has the great advantage of not introducing air into the vats to move the cap; in fact, the air can influence not only the formation of the cap but also the oxidation of the must.

FIG. 2illustrates a constructional variant of the membrane7. Two membranes7and7′ are comprised therein, arranged in cascade i.e. in such a way that the large-dimension bubbles12produced by the lower membrane7supply the overlying membrane7′. In this way it is possible to improve the effect of bubble generation internally of large vats2. In this case the second connection102of the pumping-over conduit100can be connected to the chamber27defined below one of the membranes7,7′.

The membrane applied to the fermenter ofFIG. 1is well visible inFIG. 4; the membranes applied to the fermenter ofFIG. 2are clearly visible inFIGS. 5 and 6. In substance the membranes have a semi-circular or half-moon shape, possibly bevelled or cut in some parts thereof.

FIG. 3illustrates a further constructional variant of the membrane7. It comprises a truncated cone-shaped peripheral zone21delimited centrally by a cylindrical zone22. A controllable annular opening23is included between the two surfaces, comprising an inflatable toroid24.

By modifying the inflation pressure of the toroid24it is possible to act on the dimension of the opening23in a very simple and economical way. In this embodiment too, the second connection102of the pumping-over conduit100opens in the chamber27defined below the membrane7.

Obviously it is also possible to apply to the opening20of the embodiment ofFIG. 1an appropriate device (not illustrated) able to vary the dimension of the opening20according to needs. This device (not illustrated) might, for example in the example ofFIG. 1, prolong the truncated cone surface in the direction of the imaginary vertex thereof, i.e. increasing the volume of gas collected in the chamber27or it might, more simply, exclusively vary the section of the opening without increasing the volume of the chamber27. In this second case, therefore, it would be a device that would extend horizontally either upwards, thanks to which, apart from varying the dimension of the zone of influence of the large bubbles12on the cap10, the step of generating the larger bubbles12can be varied so as to be able to influence the dimension thereof during use.

The illustrated solution thus enables preventing or at least limiting the formation of a solid cap and further enables continuously stirring the cap with the fermenting must-wine and facilitating extraction of the marc, the marc not being compacted on completion of the fermentation cycle.

In two further possible embodiments of the fermenter, illustrated inFIG. 8andFIG. 9, the second connection102of the pumping-over conduit100is placed in communication, apart from with the stretch comprised between the first connection101and the dispenser103, also with the first connection101. As illustrated inFIG. 8and inFIG. 9, the second connection102has at least an auxiliary stretch104parallel to the pumping-over conduit100. The auxiliary stretch104fills with liquid in a like way to the pumping-over conduit. The auxiliary stretch104is connected inferiorly to the first connection101and, in an intermediate zone, to the pumping-over conduit100through an intermediate fitting105. The auxiliary stretch104can be provided in an upper zone of the by-pass valve V4which allows venting of the additional tube104. The eventual injection of external gas through the injection valve V3and with the valve V2open, thrusts the liquid present in the auxiliary stretch104downwards as far as the intermediate fitting105. Having reached the intermediate fitting105, the gas thrusts the liquid towards the upper part of the pumping-over conduit100up to the dispenser103. The embodiments illustrated inFIG. 8andFIG. 9enable injecting an external gas into the pumping-over conduit, preventing the gas from mixing with the product, carrying out an injection of gas in an intermittent manner, i.e. closing the valve V2at predetermined time intervals.

FIG. 10illustrates an additional solution that can be adopted on the solution ofFIG. 7(but can be applied also toFIG. 1, 2 or 3) where an optional auxiliary conduit106is added to the conduit102, provided with a control valve V6which enables, on opening the valve, discharging part or all of the gas accumulated below the membrane just below the cap10.

FIG. 12illustrates a variant embodiment in which the dispenser103is arranged inside or below the zone normally occupied by the cap10, so as to dispense the liquid within or below the cap10. The dispenser103can be conformed as a conduit108which partially or totally crosses the cap10of marc and dispenses the solution internally of or below the cap10of marc.

FIG. 13shows a variant embodiment of the fermenter, in which the vat2is substantially a closed tank which also functions as accumulation means7of the fermentation gas. In this embodiment the dispenser103can be conformed as a dispensing conduit108which partially or totally crosses the cap10of marc and dispenses the solution internally of or below the cap10of marc. A vent valve V5is present in the upper zone of the conduit108, an opening of which enables venting the gas and a consequent precipitation by gravity in the liquid which, dragged by the gas up to the vent valve V5, exits from the lower end of the conduit108. Via the opening and closing of the vent valve V5, when the control valve V1is open, it is possible to determine the start and stop of the pumping-over. The second connection102preferably opens into the pumping-over conduit100at a greater height than the vent of the dispensing conduit108.

With the present invention it is thus possible to realise fermenters that are of simple but effective conception which, as well as being extremely economical if compared to fermenters of known type, do not require complex or expensive maintenance.

It is further possible to use the fermenter of the present invention, apart from for wine production, also for beer production and also for transforming other fermentable products, such as for example apples, potatoes or the like.