WO2005051642A1

WO2005051642A1 - Method and apparatus for pressing grapes and other juicy fruit

Info

Publication number: WO2005051642A1
Application number: PCT/IT2003/000782
Authority: WO
Inventors: Antonio Velo
Original assignee: Velo Spa
Priority date: 2003-11-27
Filing date: 2003-11-27
Publication date: 2005-06-09
Also published as: AU2003292541A1

Abstract

Method and related press (1) for pressing fruit and filtering the so obtained juice, such as for instance the material resulting from the crushing of grapes, characterized by the use of an inert atmosphere inside the casing (10) of said press (1) and, preferably, the injection of anti-oxidation adjuvants into said casing (10).

Description

METHOD AND APPARATUS FOR PRESSING GRAPES AND OTHER JUICY FRUIT

* * * DESCRIPTION The present invention refers to the pressing operation, i.e. the process used to remove from the juice obtained by crushing the fruit all those solid parts that are of no use in view of the subsequent processing of the same juice, thereby maximizing production yield. For reasons of greater convenience, reference will be made in the following description to grapes and wine-making processes, so that the described operation refers to the material that is the product of crushed grapes, i.e. the mixture of must, skins and grape-seeds resulting from the previous phases of destemrning and crushing the bunches of grapes; however, it will be readily appreciated that all considerations that are set forth in the following in this connection equally apply in the same manner to all other kinds of fruit, from which a juice has to be extracted. In most cases, for carrying out the pressing operation that is considered here, use is currently made of so-called pneumatic presses of the type described and illustrated, for example, in the publications US-A-4 024 810 and TJS-A-4 438 690. These presses are substantially constituted by a framework that supports a hollow metal cylinder, generally known as drum in the art, which is tapered at both end portions thereof and is kept rotating about its own axis, which is horizontal, by a driving motor. Inside this drum there is provided a membrane which, owing to its being swollen by compressed air injected thereinto, causes the crushed material, previously filled into said drum, to be pressed against perforated grilles provided all along the surface of the drum, which retain the solid residues, while letting the liquid phase of the crushed material, i.e. the must, flow therethrough into appropriate channels provided under said grilles. This must is then conveyed, through proper spouts or outlets, outside the press, i.e. to the further processing steps. It is a generally well-known fact that the presence of oxygen during the vinification process, except for a few specific cases in which it is accepted in properly controlled amounts, has a markedly negative, i.e. detrimental effect on the quality of the final product (oxygen is in fact responsible for the oxidation of certain constituents of the crushed mixture, such as for instance catechins and leukoanthocyanins) to such an extent that the need for suitable protective systems, such as the use of hermetically sealed containers, low temperatures and the like (so as to minimize the volume of oxygen being dissolved into the liquid must) is generally felt in the art. These systems, however, call for complex equipment and/ or particularly accurate controls to be provided and implemented in view of preventing oxygen from being metered and introduced to such amounts as to anyway prove prejudicial to the quality of the final product; in addition, these systems are in all cases relatively expensive. It therefore is a first purpose of the present invention to provide a new system for preventing oxygen from being present during pressing and filtering of the crushed material, in which this system is capable of being implemented in a simple and relatively low-cost manner. Largely known in the art are also the drawbacks that contribute to keeping at relatively low levels the efficiency of pneumatic presses owing to the currently used systems to fill the crushed material into the same presses. These systems can be divided into two main kinds, i.e. the systems based on filling the crushed material axially, i.e. through a filler provided at an end portion of the drum, and the systems based on filling the crushed material through a port provided at an intermediate position between the two end portions of the drum,, this filling system being simply referred to as "central filling" hereinafter. When a filling system of the first cited kind is used, the crushed material is introduced in the drum through an inlet conduit provided at an end portion of the same drum. It therefore ensues that, as the pressing and filtering operation goes oh, the marc tends to distribute in a substantially uneven manner inside the drum, while generally heaping up near the inlet conduit itself. In order to be able to efficiently use the entire surface or the perforated grille, the need therefore arises for the marc to be properly redistributed inside the drum. As a result, the latter is caused to rotate rather frequently in view of causing the marc to separate from the inner wall of the drum and thrown about, i.e. scattered inside the drum, in an operation that is generally referred to as marc crumbling phase in the art. These frequent rotations of the drum carry however a major drawback with them, which practically derives from the skins of the grapes rubbing against the filtering grilles: notwithstanding the fact that these grills are made in such a manner as to offer as smooth a surface as possible to the marc, the skins will anyway and unavoidably end up by getting mushy and breaking up into particles that are small enough to pass through the meshes of the filtering grilles. It can be readily appreciated that, especially when producing white wines, the contamination of the must by these minute particles is fully undesired and has therefore to be avoided by all means. When the second press-loading method is on the contrary used, the crushed material is introduced into the press through a port that is specially provided at the centre of the drum. Obviously, the same filling port must be kept open while the crushed material is being filled through a conduit into the drum, until it builds up to an adequate mass therewithin. At this point, the filling port is closed and^'the membrane is swollen up, as already indicated above. Owing to the fact that, even in this case, the need anyway arises for the introduction of crushed material into the drum to be temporary stopped every now and then, so as to obtain an adequate distribution of the same crushed material within the drum by causing the latter to rotate, the resulting waste of time practically equalizes the advantage deriving from the skins being subject to a less extent of breaking up into small particles. It therefore is a second purpose of the present invention to provide a system that reduces the operating and processing time of a pneumatic press. In view of reducing the risks arising from a contact of oxygen with the crushed grapes, or crushed material, largely known in the art is also the use of appropriate adjuvants, i.e. auxiliar ingredients in the form of chemically reducing powders, such as sulphur dioxide, or antioxidants such as ascorbic acid. However, the same operation required to fill these substances into the drum does not fail to carry a couple of drawbacks with it. In fact, if the adjuvants are filled through the same port or orifice that has been previously used to fϋl the crushed grapes, the oxygen from the atmosphere enters the drum jointly with the adjuvants themselves, which, on the other hand, tend to distribute in a poorly everi. manner inside the drum. It therefore is a further purpose of the present invention to provide a system that improves the manner and enhances the efficiency in which adjuvant substances are used during the pressing and filtering operation. Another drawback that is frequently encountered in prior-art presses is connected with water-tightness of the press during the phase in which the membrane is retracted in view of preparing the press to a new pressing and filtering operation. In particular, it has been already explained that the afore-cited must-outlet channels generally convey the must out of the drum through specially provided spouts, or similar arrangements. If no particular measure is taken in the design and construction of such spouts, or, anyway, if no proper interfaces are provided between the press and the outside ambient, outside air may be sucked into the drum therethrough. It therefore is a further purpose yet of the present invention to provide a system that is capable of doing away with the problem of air being sucked-in through the above- mentioned must-outlet spouts or apertures during the pressing and filtering operation. ' According to the present invention, these aims, along with further ones that will become apparent in the course of the following description, are reached in the use of a method and an apparatus for pressing crushed grapes, or other kinds of fruit as well, incorporating the features ,as defined and recited in the appended claims, wherein the most important one of these features lies in the ability of keeping the crushed grapes, or crushed fruit in general, in an atmosphere that is at least prevailingly constituted by one or more inert gases throughout the duration of the pressing and filtering operation. In particular, the steps involved by the method according to the present invention may be summarized as follows: introduction of inert gas in the drum; - introduction of crushed material in the drum under controlled filling conditions; - pressing of the crushed material, i.e. swelling out of the membrane, and resulting dripping and draining off, possibly preceded by an introduction of adjuvants, if desired, while at the same time recovering the inert gas into a properly provided auxiliary reservoir; - flattening out of the membrane occurring at the same time as the re-introduction of inert gas in the drum; possible repetitions, as far as necessary in order to fully extract the must from the crushed material, of the above-cited pressing and following deflating steps; final crumbling, i.e. breaking up, of the marc through the rotation of the drum, under simultaneous and/ or subsequent introduction of adjuvants in the drum. The following description of a method and an apparatus according to the present invention, in which the above-cited steps will be explained and illustrated in detail, is given by mere way of non-limiting example with reference to the accompanying drawings, in which: ' - Figure 1 is a side view of a pneumatic press according to a preferred, although not sole embodiment of the present invention, wherein the press is shown in the state in which it is being filled with crushed material and, for reasons of greater simplicity, only those parts are indicated which are in a direct connection with, or are of any relevance as far as, the present invention is concerned, since all other parts are well-known in their construction to all those skilled in the art; - Figure 2 is a top view of the press shown in Figure 1; - Figure 3 is a front view of the press shown in Figure 1; - Figure 4 is a partially cross-sectional view of a valve of the type used in the press shown in the preceding Figures; - Figure 5 is a schematical view of the operation of a press according to the present invention. Figure 1 illustrates a press 1 according to the present invention, which is controlled in a manner known as such in the art by electronic data processing means (not shown), which determine the sequence of the steps included in the method, which is also part of the present invention, in the manner that will be described in greater detail further on. This control action extends to cover the totality of the functional parts provided in the same press, so that the method according to the present invention is fully automated, i.e. can be carried out in a fully automatic manner, thereby adding a further advantage to the present invention itself. The press 1 comprises a cylindrical drum 10 showing a tapered form at the end portions thereof and sustained, again at the end portions thereof, by a framework 5 (shown in part only), which is provided with generally known driving and rotary-joint means (not shown) to enable the drum 10 to be caused to rotate in a controlled manner. On the side surface thereof, this drum is provided with a number of apertures. In addition, for filling the crushed grapes thereinto, the drum 10 is provided with a mouth 12, which is situated in a substantially central position, and to which a conduit 14 is coupled in a tightly sealed manner. This conduit 14 is coupled to said mouth 12 via a kind of gate valve 15, or guillotine-type valve 15, and is supplied by a feeding pump 17 provided for dehvering the crushed grapes (see Figure 5). The conduit 14 extends along the side of the drum 10 to reach an end portion of the latter, where, by means of a rotary joint 16 (of a kind known as such in the art), it links up with an axial conduit 16b that extends further on towards the pump 17 (not shown in Figure 1). Therefore, even when the drum 10 is rotating the crushed grapes can be introduced in the drum 10 through the conduit 16b, the joint 16, the conduit 14 and the valve 15 in the given order and sequence. Conduits 20, which are associated to valves 21 near the drum 10, fit into the dru 10 via nozzles (not shown). Although a single one of these conduits is shown in Figure 2 for reasons of greater simplicity, it is appreciated that a larger number of them is usually provided. These conduits 20 extend from an inert-gas delivery reservoir 25 (see Figure 5), a valve 22 being installed downstream of said reservoir. This reservoir is used to store the inert gas to be introduced in the press; although reference is constantly made here and elsewhere in this description to nitrogen as an inert gas, it will be readily appreciated that also other types of inert gases may be considered for use in this connection. Said reservoir

25 may for instance be implemented by making use of the generally known system based on the use of an inflatable membrane for storing the inert gas, in which said membrane stores the gas in its interior by swelling out, whereas it flattens out, i.e. regains its initial state upon releasing the gas stored therein. ; Upstream of the valves 21, the conduits 20 (see Figure 5) branch out into conduits

26 connected to one or more pumps 23. Said conduits 26 carry the chemical adjuvants which, as pushed forward by the pumps 23, are eventually delivered into the drum 10, as this shall anyway be illustrated in greater detail further on. With reference to Figure 2, the conduit 20, in the same way as the conduit 14, reaches up to a rotary joint and extends further on coaxially with the drum 10. On the outer surface of the drum 10 there is provided an array of draining spouts 30, or similar outlet provisions, which are preferably provided in a side-by side arrangement relative to each other, as gathered on a single side of the same drum. From these draining or outlet spouts 30 the must is drawn off, via a manifold 32, and driven out of the drum 10 by the action of the press 1. On the spouts 30 there are mounted guillotine- type valves 40 (see Figure 4), the peculiar advantages of which shall be described in greater detail further on. To a draining spout 30 there is also coupled a full-level detector 28 (indicated schematically in Figure 5), the use and the advantages of which shall be explained further on. To the press 1 there are also associated known means (not shown) for inflating, i.e. swelling out, and deflating the membrane inside the drum 10. The method of the invention shall now be described in the peculiar steps thereof:

I. The inner volume of the drum 10 is filled with nitrogen, in such a manner as to ' . create the desired inert atmosphere for the crushed material to be pressed. In particular (see Figure 5), upon the valves 21 and 22 having been opened and the valves 40 and 15 having been closed, the nitrogen gas is transferred from the reservoir 25 into the drum 10 through the conduits 20. This transfer of the nitrogen gas can be carried out by means of a pump (not shown), by pressure delivery or by any other suitable means known in the art. II. The crushed material, e.g. the crushed grapes, is filled into the drum 10 by opening the valve 15 and energizing the pump 17; at the same time, the nitrogen gas is forced out of the drum 10 and is conveyed towards a recovery reservoir. This recovery reservoir can be either the same feeding reservoir 25 or a second auxiliary reservoir. The full-level detector 28 detects the level reached by the crushed material to be pressed inside the drum 10 and communicates the so detected data directly to the electronic data processing means of the press 1. For this effect to be achieved, the press is arranged in such a manner as to ensure that the spout 30, which said level detector is coupled to, comes to be situated at the highest point of the drum 10. When the planned level is reached, the, pump 17 is stopped, the valve 15 is closed and the level detector 28 is withdrawn. III. At this point, an early introduction of adjuvants into the drum 10 may take possibly place. The details of this operation are described below under step VII. IV. After a possible preliminary dripping-off phase taking place "naturally" by gravity, the membrane provided inside the drum 10 is inflated, i.e. caused to swell out, in any of the manners known as such in the art, so as to start the actual pressing phase. The must flows out of the drum 10 through the spouts 30 and the valves 40, which are now open, whereas all other valves are closed. The expansion of the membrane causes also the nitrogen gas to be forced out of the drum 10 and be recovered as described under step II above.

■ V. The membrane is then deflated and the resulting lowering in the. pressure inside the drum is compensated for by the introduction of nitrogen gas in the same drum 10. Namely, since the membrane being deflated and retracting into its initial configuration creates a negative pressure inside the drum 10, in order to enable such retraction to take place, the nitrogen gas is let into the drum 10 in the above described manner. VI. ■ If necessary, ϋxe previous steps IV and V, in which the crushed material is pressed and the membrane is then deflated under compensation of the resulting lowering in pressure through the introduction of nitrogen gas in the drum 10, are repeated as many times as required until the must is fully extracted from the crushed material. VII. The layer of metre lining the interior of the drum 10 is caused to, crumble by letting the same drum perform a number of rotations. When the drum 10 is caused to rotate in ,this manner, all valves are closed. In a preferred, although not sole embodiment of the present invention, the adjuvants are injected into the drum 10 before and/ or after such crumbling of the metre layer. To do so, the valves 21 are opened and the adjuvant feeding pumps 23 (see Figure 5) are operated. As a result, the adjuvants (see Figure 1) reach the interior of the drum 10 by passing through the conduit 16b, the rotary joint 16, the conduit 20 and, finally, the valves 21. It is fully apparent that the introduction of the full-level detector 28 in the step II, further to enabling the method to be automated and, ultimately, to be carried out in a much quicker manner, is effective in preventing crushed material from possibly leaking out of the drum 10. Fully apparent is further the fact that the use of valves 40 coupled to the outlet spouts 30 enables ambient air to be prevented from being possibly sucked in from outside, and thus entering the drum 10, during the phase in which the membrane inside the same drum is deflated. Such penetration of ambient air from outside would in fact nullify the -inert atmosphere that has built up inside the drum during the pressing phase. The selection of guillotine-type valves as a choice for said valves 40 is suggested by considerations of efficiency and simplicity of construction; however, other types of valves, such as for instance gate valves or even conventional check valves, may of course be considered for use in this application, as well. It will be also readily appreciated that the method according to the present invention may be embodied without providing the afore-cited nitrogen re-circulating circuit, i.e. by using a less-than-optimal solution in which the nitrogen let into the drum 10 at each pressing cycle, is eventually dispersed into the outside atmosphere. It will be finally appreciated that a number of non-significant deviations from the inventive concept as set forth in the above description and illustrated in the accompanying drawings are possible without departing from the scope of the invention as defined by the appended claims. * * * * *

Claims

CLAIMS 1. Method for pressing fruit, such as for instance the material resulting from crushing grapes, and filtering the juice resulting from such pressing, said method comprising the steps of: loading said crushed fruit into a sealed casing (10); submitting said crushed fruit to pneumatic compression, while at the same time filtering the so extracted juice, one or more times, as necessary, inside said sealed casing (10); letting out the filtered juice for conveyance to further processing steps, characterized in that an inert atmosphere is used inside said casing (10) during processing. 2. Method according to claim 1, characterized in that it comprises at least a step, preceding and/ or subsequent to said pressing and juice-filtering step, which consists in injecting per se known inorganic and/ or organic adjuvant substances to counteract oxidation into said sealed casing (10), such as for instance chemically reducing powders or anti-oxidants. 3. Method according to claim 1 or 2, characterized in that said filling step is carried out by keeping the level of the crushed fruit being loaded into the casing (10) under control. 4. Method according to any of the preceding claims 1 to 3, characterized in that said inert atmosphere is obtained by letting at least an inert gaseous substance into said casing (10). 5. Method according to claim 4, characterized in that said inert gaseous substance is nitrogen. 6. Method according to claim 4 or 5, characterized in that said at least an inert gaseous substance is recovered for repeated use in several pressing cycles. 7. Press (1) for pressing fruit, such as for instance the material resulting from crushing grapes, and filtering the juice resulting from such pressing, said press comprising a rotating casing (10) provided with means (12, 15, 14, 17) for filling the crushed fruit into the casing (10), means to rotatably drive said casing after filling said fruit thereinto, pneumatic means to press said fruit and, at the same time, filter the so extracted juice, means (30, 32, 40) for letting out the filtered juice for conveyance to further , processing, characterized in that it further comprises means (20, 21, 22, 25) adapted to create and keep inert-atmosphere conditions inside said casing (10). 8. Press according to claim 7, characterized in that said means (20, 21, 22, 25) adapted to create and keep inert-atmosphere conditions in said casing (10) comprise a supply (25) of at least an inert gas, as well as means (20, 21) for injecting said at least an inert gas into said casing (10) in a controlled manner. 9. Press according to claim 8, characterized in that said supply (25) is at least a reservoir of inert gas, such as for instance nitrogen, communicating either via a valve (22) or directly, with a pluraHty of conduits (20), which are in turn connected to valves (21) provided to adjust the flow rate from and towards the interior of said casing (10). 10. Press according to claim 9, characterized in that said at least an inert gaseous substance is used repeatedly to perform several pressing cycles by conveying it to and drawing it off the recovery reservoir (25) through said conduits (20) and adjusting the flow rate thereof with the help of said valves (21). 11. Press according to claim 10, characterized in that said recovery reservoir (25) consists of an inflatable membrane. 12. Press according to any of the preceding claims 7 to 11, characterized in that it further comprises sensor means (28) to detect the level reached by the fruit being filled into the casing (10). 13. Press according to any of the preceding claims 7 to 11, characterized in that said casing (10) comprises apertures (30) for drawing off the filtered juice, these apertures being coupled with tightly sealing valve means (40). 14. Press according to claim 13, characterized in that said valve means (40) are guillotine-type valves or the like. 15. Press according to any of the preceding claims 7 to 14, characterized in that it further comprises means (23, 26, 21) for injecting anti-oxidation adjuvant substances into the casing (10). 16. Press according to claim 15, characterized in that said means (23, 26, 21) for injecting anti-oxidation adjuvant substances into the casing (10) comprise a pump (23) connected, to a pluraHty of conduits (26), these conduits being connected with the inner volume of said casing (10) via valves (21) or the like. 17. Press according to any of the preceding claims 7 to 16, characterized in that the functional parts thereof are controlled by at least a process control device of a per se known kind.