Patent Description:
In the following description, reference will be made, purely by way of a non-limiting example, to vinification and in particular the extraction of must by pressing grape berries, it being understood that the same principles may be advantageously used for the extraction of juice by pressing fruit or vegetables.

In the so-called white wine, rosé wine and red wine vinification processes, the common starting point is to obtain the must from the grapes which have been harvested.

The differences arise later, since in the case of white wine vinification the must is separated from the stalks and skins, while in the case of rosé wine and red wine the must remains mixed with the solid pressing residue (skins and pips) for the maceration phase, with a contact time between must, skins and pips which varies (a relatively short time for rosé wine and a much longer time for red wine vinification).

For simpler and easier description, below reference will be made primarily to white wine vinification, where the grapes are subjected to pressing, preferably without prior destemming, so as to make use of the stems for the subsequent straining operation, i.e. for separation of the must from the skins and seeds.

Alternatively, the previously destemmed grapes are pressed in membrane presses, where the destemmed grapes occupy a part of a hollow cylinder containing a membrane which, in the rest condition, is adjacent to one of the walls of the cylinder. These presses are also called side membrane presses.

By injecting a fluid under pressure from the side of the membrane opposite to that in contact with the loaded batch of grapes, the membrane compresses the berries causing them to break and the juice to escape through a number of draining holes provided in the adjacent wall of the cylinder. In this way, the skins and seeds are retained inside the cylinder and the amount of suspended solids in the juice extracted from the press is limited.

This method of pressing, and therefore obtaining the must, is obviously discontinuous, since it involves four cycle phases, namely:.

If it is considered, as an example, that each load of a <NUM> hectolitre press comprises an average of <NUM> tons of grapes from the harvest, and that pressing can take from <NUM> hour <NUM> minutes to <NUM> hours,.

it is clear that the cycle time is quite long, while the operational requirements are such that a harvest must be concentrated within the time span of a few days.

In addition, the harvested grapes must be processed as soon as possible, in view of the rapid deterioration or at least the initial fermentation which may occur during the waiting time and which affects the characteristics and quality of the wine subsequently produced.

The pressing time has been substantially reduced by using cylindrical presses in which the membrane is in the form of a bag arranged in a diametral plane, so that the expansion takes place towards the entire cylindrical wall (obviously provided with draining holes over its entire surface). These membrane presses, also known as central membrane presses, owing to the arrangement of draining holes over the entire surface, allow a larger quantity of grapes to be loaded into a single press. For example, a <NUM> hectolitre central membrane press may be loaded with <NUM> tons of grapes, that is, for the same size, with <NUM>% more grapes compared to side membrane presses.

In this way it is possible to reduce substantially the duration of the pressing step (to <NUM>-<NUM> hours), without, however, eliminating the abovementioned above problems. In fact, even when using a central membrane press, the pressing method remains discontinuous. <CIT> discloses a filter press suitable for separating a liquid fraction from a solid mass, comprising at least one filtration column which includes at least one loading/pressing module for said sludge, said filtration column being fixed and extending vertically with respect to a reference plane parallel to the ground. <CIT> also discloses a pressing plant comprising a plurality of filter presses disposed in such a manner as to operate in series and/or in parallel.

As an alternative to pressing of the type briefly described above, it is possible to use continuous pressing systems consisting essentially of a helical screw press: in this case, however, the gain in pressing speed is accompanied by a deterioration in the quality of the must, since pressing the grape berries against the walls surrounding the screw also results in greater fragmentation of the skins and shredding of the seeds.

For this reason, the resultant must also contains substances extracted from the skins and seeds that adversely affect the resultant wine from a qualitative point of view.

In addition, cleaning the screw and the interstices in the cylinder which contains the screw is very difficult and takes longer than washing a membrane press.

In a nutshell, the main problem hitherto not solved is the production of a must from harvested grapes which allows continuous processing of the grapes in short cycle times, preventing the skins and/or grape seeds from releasing unwanted components in the wine.

Another problem not solved hitherto is that of the versatility of the plant, since often the pressing of a first type of grape is followed by the pressing of grapes of a completely different type (for example, when changing from white wine vinification to red wine vinification): until now it has been necessary to wait for the press or presses (if there are more than one) designed for the pressing of white grapes to finish the cycle with the final washing step, before loading the harvested grapes to be used for red wine vinification.

As already mentioned, storing the harvested grapes for more or less long periods before performing pressing has a negative impact on the quality of the resultant wine.

In order to remedy this problem, the batches of grapes awaiting pressing are often stored at low temperatures in order to temporarily stop fermentation.

The winery, therefore, must equip itself with temperature control and refrigeration systems, machinery which is obviously expensive both in terms of purchase price and in terms of operating and maintenance costs.

The main object of the present invention is to provide a plant and a method able to solve substantially the problems and drawbacks briefly outlined above.

Another object of the present invention is to provide a plant and a method for the extraction of juice from vegetable raw material, in particular for the extraction of must from harvested grapes, which are flexible and adaptable during use in order to cope with both peaks in production and the treatment of vegetable raw material of varied origin, in particular grape berries of different types.

A further object of the present invention is to provide a plant for the extraction of juice from vegetable raw material, in particular for the extraction of must from harvested grape berries, which may be easily expanded and implemented if necessary.

These and other objects are achieved with a plant for the extraction of juice from vegetable raw material, in particular for the extraction of must from grape berries, as defined in claim <NUM>, and with a method for the extraction of juice from vegetable raw material, in particular for the extraction of must from grape berries, according to claim <NUM>.

In order to illustrate more clearly the innovative principles of the present invention and its advantages compared to the prior art, examples of embodiment applying these principles will be described below with the aid of the <FIG>, which shows a schematic diagram of an embodiment of a plant according to the invention.

<FIG> shows a preferred embodiment of a plant, denoted overall by the reference number <NUM>, for continuous pressing in a vinification process provided according to the invention.

The plant <NUM> comprises three presses for continuous pressing of grapes, denoted by the reference numbers <NUM>, <NUM> and <NUM>, respectively, said presses being preferably of the central membrane type and comprising a plurality of draining holes (not shown in the attached figure).

It is understood, however, that reference to such presses is not be regarded in a limiting sense, in that the present invention may also be implemented using other known types of discontinuous presses.

Preferably, the presses <NUM>, <NUM>, <NUM> are arranged in parallel with each other.

Each press is supplied by a respective hopper or tank <NUM>, <NUM> and <NUM> which is filled with the harvested grapes to be pressed for the production of must.

The tanks <NUM>, <NUM> and <NUM>, which are components known per se, may be for example a stainless steel tank or a wooden vat. Each tank <NUM>, <NUM>, <NUM> may be loaded with grapes as such, or with grapes obtained from a destemming or a destemming/pressing step in the case of white wine vinification. Otherwise, in the case of red wine vinification, each tank <NUM>, <NUM>, <NUM> is loaded with grapes obtained from a maceration vat (not shown in the figures) following a prior maceration step.

Each tank <NUM>, <NUM> and <NUM> communicates with the respective press <NUM>, <NUM>, <NUM> by means of a pump - respectively indicated by <NUM>, <NUM> and <NUM> - positioned upstream of a multi-path distribution valve <NUM>, <NUM> and <NUM> communicating with the respective press <NUM>, <NUM>, <NUM> by means of an inlet duct 30a, 30b and 30c.

According to the invention the distribution valves <NUM>, <NUM>, <NUM> are movable at least between two positions. In a first position each inlet duct 30a, 30b, 30c is connected to a first hopper and in the second position each inlet duct 30a, 30b, 30c is closed or connected to at least one second hopper different from the hopper to which it is connected when the respective valve is located in the first position.

Advantageously, the three presses <NUM>, <NUM>, <NUM> may be supplied from a single tank, for example the tank <NUM>, and the pump <NUM> associated with this tank <NUM> may regulate and perform the selectively supplying of the grapes to the plurality of presses by means of the distribution valves <NUM>, <NUM>, <NUM>. For this purpose, as shown in <FIG>, the three distribution valves <NUM>, <NUM>, <NUM> are connected by means of a single duct <NUM>.

Obviously, the number of presses, and consequently the number of respective hoppers, may also be more than three depending on the production needs of the plant. In this case the implementation of this particular type of plant is particularly simple.

Moreover, a line <NUM> for supplying the washing water may be provided, said line being connected with each of the tanks <NUM>, <NUM>, <NUM> and with each of the presses <NUM>, <NUM>, <NUM> so as to supply the washing water inside the tanks <NUM>, <NUM>, <NUM> and the presses <NUM>, <NUM>, <NUM> at the end of the pressing process.

The must produced in each press <NUM>, <NUM>, <NUM> is channelled into a respective main outlet duct, respectively indicated by <NUM>, <NUM> and <NUM>. Each main outlet duct <NUM>, <NUM>, <NUM> communicates with the draining holes of the corresponding press so as to convey the must produced by pressing.

Each press <NUM>, <NUM>, <NUM> is provided with a further outlet, respectively indicated by <NUM>, <NUM> and <NUM>, for the pomace produced during pressing, these outlets leading into a common outlet <NUM>. Alternatively, the presses <NUM>, <NUM>, <NUM> discharge the pomace into a hopper equipped with a helical screw for discharging the pomace externally.

In the embodiment shown, each main outlet duct <NUM>, <NUM>, <NUM> for the must or the juice output from each press <NUM>, <NUM>, <NUM> is connected via valve means <NUM>, <NUM>, <NUM> to three discharge branches: respectively 36a, 36b, 36c for the outlet duct <NUM> of the press <NUM>; 38a, 38b and 38c for the outlet duct <NUM> of the press <NUM>; and 40a, 40b, 40c for the outlet duct <NUM> of the press <NUM>.

The branches 36a, 36b, 36c; 38a, 38b, 38c; 40a, 40b, 40c can be selected, by operating the valve means <NUM>, <NUM>, <NUM> depending on the vegetable raw material treated in each press <NUM>, <NUM>, <NUM>. Advantageously, one of the discharge branches 36a, 38c, 40c, is dedicated for discharging the washing water.

Preferably, the discharge branches 38a, 38b, 38c of the second press <NUM> and/or the discharge branches 40a, 40b, 40c of the third press <NUM> can be connected to the discharge branches 36a, 36b, 36c of the first press <NUM>.

In detail, these branches 36a, 36b, 36c; 38a, 38b, 38c; 40a, 40b, 40c can be connected together by means of discharge headers indicated by <NUM>, <NUM> and <NUM>.

Advantageously, the branches 36a, 38a and 40a can be selectively connected to the header <NUM>; the branches 36b, 38b and 40b to the header <NUM>; and the branches 36c, 38c and 40c to the header <NUM>. With the operating modes explained below, the branches 36a, 38a, 40a may be used for a first quality (A) of must, the branches 36b, 38b, 40b for a second or different quality (B) of must, and the branches 36a, 38c, 40c for the washing water.

Below, the expression "must of quality A" is used to indicate the must obtained by a first pressing of the berries inside each of the presses <NUM>, <NUM>, <NUM>, while the expression "must of quality B" means the must obtained from a subsequent pressing of the same berries inside each of the presses <NUM>, <NUM>, <NUM>.

As shown, the outlet duct <NUM> of the first press <NUM> communicates, via the branches 36a, 36b and 36c and the discharge headers <NUM>, <NUM> and <NUM>, respectively with end outlets for the product, indicated respectively by 62a for the quality A product, by 62b for the quality B product and by 62c for the washing water.

Suitable branched ducts <NUM> and <NUM> (provided with control valves) connect the discharge headers <NUM> and <NUM> to the discharge header <NUM>. Said branched ducts <NUM>, <NUM> may be advantageously used to convey the washing liquid from the discharge header <NUM> to the headers <NUM> and <NUM>, after the pressing product (for example quality A or B product) has been discharged via the outlets 62a and 62b.

The branches 38a, 38b and 38c of the outlet duct <NUM> of the second press <NUM> can be connected, not only to the headers <NUM>, <NUM>, <NUM>, but also to respective outlets <NUM>, <NUM> and <NUM> for discharging, respectively, the quality A product, the quality B product or the washing water.

The branched ducts <NUM> and <NUM> connect the branches 38a and 38b respectively to the outlets <NUM> and <NUM>.

Similarly the branches 40a, 40b and 40c of the outlet duct <NUM> of the third press <NUM> can be connected, not only to the headers <NUM>, <NUM>, <NUM>, but also to respective outlets <NUM>, <NUM> and <NUM> for discharging, respectively, the quality A product, the quality B product or the washing water.

Also present are branched ducts <NUM> and <NUM> which connect the branches 40c and 40b to the outlets <NUM> and <NUM>.

Since there is the possibility that the three presses may be loaded with three different starting vegetable raw materials, for example the presses <NUM> and <NUM> may be loaded respectively with white grapes and red grapes and the press <NUM> may be loaded with pears or apples, the possibility is provided (not shown in the figures, but able to be easily understood and therefore realized by the person skilled in the art) of using the discharge outlet 40c of the press <NUM> for the outflow of the juice instead of the washing water or providing a fourth discharge branch for at least one of the presses or for each of them.

The main outlet ducts <NUM>, <NUM>, <NUM> and the branched ducts <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> comprise respective valves for selectively discharging the juices and the musts or the washing water via the respective outlets.

Advantageously, the plant <NUM> is provided with a control unit (not shown in the figures) configured to control the selective activation of the pumps <NUM>, <NUM>, <NUM> of the distribution valves <NUM>, <NUM>, <NUM> and the discharge valves described above.

As already mentioned, <FIG> shows the solution comprising three hoppers <NUM>, <NUM>, <NUM> which can be each connected, via suitable operation of the distribution valves <NUM>, <NUM>, <NUM>, to each press <NUM>, <NUM>, <NUM>.

Obviously, this embodiment does not exclude the possibility of providing one or two hoppers which serve all three presses <NUM>, <NUM> and <NUM>.

In this case, the distribution valves <NUM>, <NUM>, <NUM> provided in the circuit downstream of the hoppers are designed to convey the grapes to be pressed, pumped by the appropriate pump, towards the press which is in each case is preselected by the control unit.

On the basis of the above description the method for the extraction of juice from vegetable raw material, in particular for the extraction of must from grapes, according to the present invention is now described.

This method is characterized by the following steps:.

Advantageously, the transfer of the vegetable raw material from the hopper <NUM> of the first press <NUM> to the inlet duct 30b of the second press <NUM> may be performed when the first press <NUM> is completely filled. In this way, the method according to the present invention allows a quantity of vegetable raw material which would be too much for the first press <NUM>, but which may be easily pressed inside a second press <NUM>, to be diverted to the second press.

Similarly, in the case where a third press <NUM> is connected in parallel to the first press <NUM> and to the second press <NUM>, once a predefined filling percentage filling of the second press <NUM> is reached, for example also when the second press is completely full, by suitably operating the valve means <NUM>, <NUM>, <NUM> the vegetable raw material from the hopper <NUM> may be transferred to the inlet duct 30c of the third press <NUM> until a predefined filing percentage thereof is reached.

At the end of the pressing step inside the third press <NUM>, again by means of actuation of the corresponding valve means <NUM>, the corresponding inlet duct of the third press <NUM> may be supplied with washing water.

The second press and the third press, via the corresponding valve means <NUM>, <NUM>, may also be connected to a second hopper <NUM> and/or to a third hopper <NUM> loaded with vegetable raw material different from that of the first hopper <NUM>.

Advantageously, during the transfer of the vegetable raw material from the first hopper <NUM> to the first press <NUM>, simultaneously or alternately the transfer of the vegetable raw material from the second hopper and/or from the third hopper to the second press <NUM> and/or to the third press <NUM> may take place.

To summarize, the plant according to the present invention has essentially three possible operating modes:.

In mode (i) the outlets 62a and 62b will be used in succession for the must X of quality A and B, respectively, and also the outlet 62a for the washing water when, after pressing, washing of the presses and the entire plant is performed. Therefore the outlets <NUM>, <NUM> and <NUM>, as well as the outlets <NUM>, <NUM> and <NUM>, will be closed and not used.

In the mode (ii) the outlets 62a and 62b will be used, respectively for the must X of quality A and B obtained from the presses <NUM> and <NUM>, so that the outlets <NUM>, <NUM> and <NUM> will be closed, while the outlets <NUM>, <NUM> and <NUM> will be open and operative, for the must Y of quality A and B of the press <NUM> and for the corresponding washing water.

Finally, in the mode (iii) all the outlets will be used, namely the outlets 62a, 62b and 62c for the press <NUM>, the outlets <NUM>, <NUM> and <NUM> for the press <NUM>, and the outlets <NUM>, <NUM> and <NUM> for the press <NUM>. In detail, the outlet 62a will be used for the must X of quality A, the outlet 62b will be used for the must X of quality B, and the outlet 62c will be used for the washing water.

Similarly, the outlet <NUM> will be used for the must Y of quality A, the outlet <NUM> will be used for the must Y of quality B, and the outlet <NUM> will be used for the washing water.

Finally, the outlet <NUM> will be used for the juice Z of quality A, the outlet <NUM> will be used for the juice Z of quality B, and the outlet <NUM> will be used for the washing water.

The implementation of the preferred working mode may be performed by means of the selective activation of the pumps <NUM>, <NUM>, <NUM> of the valve means <NUM>, <NUM>, <NUM> and the discharge valves by means of the control unit.

Below, by way of example, some operating modes of the plant described above are illustrated, with a comparison between central membrane presses and side membrane presses also being made.

Below reference will also be made to a short cycle and a long cycle. The difference in the duration of the pressing cycle is determined by the difficulty with which the must is extracted from the grapes. This factor depends on the type of grape, the terrain, the climate, the winemaking methods used and also the type of wine to be obtained.

It should be considered that with central membrane presses the short cycle may have a duration of <NUM> minutes and the long cycle a duration of <NUM> minutes. In the case of side membrane presses the short cycle may have a duration of <NUM> minutes and the long cycle a duration of <NUM> minutes.

A plant comprising three central membrane presses each with a capacity of <NUM> hl outputs a constant flow, for each press, equal to:.

A plant comprising three side membrane presses each with a capacity of <NUM> hl outputs a constant flow, for each press, equal to:.

A plant comprising four central membrane presses each with a capacity of <NUM> hl outputs a constant flow, for each press, equal to:.

A plant comprising four side membrane presses each with a capacity of <NUM> hl outputs a constant flow, for each press, equal to:.

A plant comprising five central membrane presses each with a capacity of <NUM> hl outputs a constant flow, for each press, equal to:.

A plant comprising five side membrane presses each with a capacity of <NUM> hl outputs a constant flow, for each press, equal to:.

From the above data it can also be noted how the plant with central membrane presses is more advantageous than the plant with side membrane presses. In order to obtain the same output as a plant with three central membrane presses, essentially five side membrane presses must be used.

From the above data of the second example it can also be noted how the plant with central membrane presses is more advantageous than the plant with side membrane presses.

The above description clearly illustrates the main advantage achieved with the present invention, namely the flexibility of use, so that the plant is able to cope with production peaks associated with a single grape type (case (i)), and the change-over from one type of product to another, as occurs for example when the pressing of white grapes must be carried out along with the pressing of grapes for red wine or rosé wine vinification (case (ii)).

An equally important advantage of the present invention consists in the fact that the production capacity of the individual press, understood as being the amount of product which may be processed, is of less importance, while the reduction in the time needed to press given amounts of grapes becomes a decisive factor.

This is a major advantage considering that, as already mentioned, the harvest is concentrated within the space of very few days and the time spent by the grapes inside the collection and transport carts or inside the storage tanks results in a deterioration in the quality of the must and therefore of the resultant wine following the premature start of fermentation, unless the harvested grapes are kept under refrigerated conditions, which obviously increases production costs.

The above description refers to a plant comprising three presses, but this solution must not be regarded as being as the only one possible, since it is envisaged and may be envisaged providing a plant which comprises at least two presses, the number of said presses being able to be increased to also more than three, preferably to an even number and a multiple of two or three.

Claim 1:
Plant (<NUM>) for the extraction of juice from vegetable raw material, in particular for the extraction of must from grape berries, of the type comprising at least two presses (<NUM>; <NUM>, <NUM>), provided with an inlet duct (30a; 30b, 30c) and a first outlet duct (<NUM>; <NUM>, <NUM>) for the extracted juice and a second outlet duct or discharge opening (<NUM>; <NUM>, <NUM>) for the solid residues or lees of the starting vegetable raw material, said presses (<NUM>; <NUM>, <NUM>) being of the membrane type and being provided with draining holes communicating with said first outlet duct (<NUM>; <NUM>, <NUM>), said inlet duct (30a; 30b, 30c) being connected both to a hopper (<NUM>; <NUM>, <NUM>) for loading and supplying said vegetable raw material and to a washing water supply (<NUM>), characterized in that
said at least two presses (<NUM>; <NUM>, <NUM>) are mounted in parallel with each other and on said inlet duct (30b, 30c) of the second (<NUM>, <NUM>) of said at least two presses (<NUM>; <NUM>, <NUM>) valve means (<NUM>, <NUM>) are provided which are movable between two positions, a first position wherein the inlet duct (30b, 30c) of said second press (<NUM>, <NUM>) is connected to said loading and supply hopper (<NUM>) of said first press (<NUM>) and a second position wherein said second press (<NUM>, <NUM>) is connected to a loading and supply hopper (<NUM>, <NUM>) for vegetable raw material different from that of said first press (<NUM>).