EP2342071A1

EP2342071A1 - Pressing method and press

Info

Publication number: EP2342071A1
Application number: EP08876091A
Authority: EP
Inventors: Antonio Velo
Original assignee: Velo SpA
Current assignee: Velo SpA
Priority date: 2008-11-05
Filing date: 2008-11-05
Publication date: 2011-07-13
Also published as: WO2010052739A1

Abstract

A pressing method is described for an animal or vegetable product, for example grapes or crushed material, after its loading inside the drum (12) of a pneumatic press (10), the drum being equipped with an inflatable, inner pressing membrane (20) and with two or more drainage outlets (24, 25, 26 ) of juice or liquid of the product. The method comprises the phases of (i) leaving open only a subset (25) of said outlets; (ii) pressing the product by inflating the membrane; (iii) opening a higher number (24, 26) of said outlets, eventually all; (iv) pressing again the product by inflating the membrane. The method solves the problem of obtaining a better quality in the pressed juice or liquid by filtering it at best.

Description

"PRESSING METHOD AND PRESS"

DESCRIPTION

The invention relates to a pressing method for an animal or vegetable product and to a press, preferably pneumatic, for implementing the method.

As a vegetable product olives or fruit in general to be pressed can be used, such as fresh or crushed grapes.

As an animal product e.g. the stomach of calves or ovi-caprines for the extraction of rennet can be used.

Referring to grapes as an example, a pneumatic press is known from WO2005/051642. It describes a press comprising a rotatable cylindrical drum in which the grape is loaded, and an inflatable membrane inside the drum which upon expanding compresses the grapes against the walls of the drum. The extracted juice passes through some filtering meshes located in correspondence of draining holes in the drum, from which it is expelled by the pressing action and it is then channeled by a collecting system.

For structural and economical reasons the draining openings are arranged on a single arc of circumference with a center angle of about 180 degrees. The aim is to foster an efficient and acceptably fast draining by giving the liquid must several ways-out to come out.

The main object of the present invention is to allow a better quality in the pressed product (juice) to be obtained, raising the quality performance of the known presses.

This object is achieved by a pressing method for an animal or vegetable product, for example grapes or crushed material, after its loading inside the drum of a pneumatic press, the drum being equipped with an inflatable, inner pressing membrane and with two or more drainage outlets of juice or liquid of the product, characterized by the phases of (i) leaving open only a subset of said outlets; (ii) pressing the product by inflating the membrane; (iii) opening a higher number of said outlets, eventually all; (iv) pressing again the product by inflating the membrane.

The invention thereby accomplishes a more valuable juice at the first pressing.

The benefit stems from a little intuitive and nothing short of amazing effect. Leaving open only part of the openings forces the first must leaving the drum to flow through the entire solid mass of the crushed material. In essence, with the invention the average path lengthens which the liquid must travel to escape from the drum. In doing so, the solid parts to go through increase, and consequently increases the sieve-effect which such solid parts develop with respect to the liquid. This, also helped e.g. by an appropriate pressing program, compared with liquids derived from traditional presses allow to obtain drained liquids with very low content in solids (commonly called dregs) and with lower content of highly oxidable constituents (e.g. catechins, leucoantocians, etc.).

The method has several advantageous phases, described in the dependent claims, including the following.

E.g. in phase (i) said subset may be a minority of said outlets, preferably one third. In this way a traditional drum provided with openings on a semi-circumferential arc becomes pervious along an arc of about 60 degrees, value which has yielded good practical results. To emphasize at most the sieve-effect (the path of the liquid or juice through the solid part lengthens at most), in the phase (i) only one outlet of the drum may be left open.

To obtain a valuable part of the juice or liquid, stage (iii) occurs only after one pressing movement of the membrane, during which movement the product is pressed for the first time and its liquid or juice is optimally filtered and drained. To implement the method, the invention adopts a pneumatic press comprising a drum, for loading the product therein, equipped inside with an inflatable pressing membrane and with two or more drainage outlets for liquid or juice of the product.

To force the liquid or juice to leave the drum through a reduced number of outlets, the press comprises means destined to selectively close a subset of said outlets during an initial pressing phase, e.g. valve means.

To automatically manage the functions and the operational pressing steps it is good for the press to comprise a processing unit arranged to control the means destined to close, e.g. being configured to leave open only one outlet or a minority of the outlets during an initial pressing phase.

For channeling the juice or liquid draining from the drum with different quality, the press may include a diverter assembly for the flow of liquid or juice to discriminate the liquid or juice during and/or after the initial pressing phase to at least two distinct conveyance circuits.

The two circuits allow e.g. to store the different qualities of juice or liquid in different tanks.

The assembly may include valve means, preferably controlled by the processing unit, and adapted to close/open in the diverter assembly at least one outlet for the liquid or juice so that at least one outlet is open when the remaining outlets are closed and vice versa. In this way the liquid is easily sorted.

As an example a method and a press for grapes according to the invention will now be described with reference to drawings, where

Fig. 1 shows an assonometric view of the press;

Fig. 2 shows a graph of the pressing pressure as a function of time; Fig. 3 shows a simplified vertical cross-section of part of the press in fig. 1 according to the plane Ill-Ill in Fig. 4;

Fig. 4 shows a simplified side view of the press in fig. 1. A press 10 (figures 1 , 3 and 4) is formed by a hollow drum 12, tumable around a horizontal axis X, which is supported by a frame 11. Through a tightly closable hatch 14, grapes or crushed material 18 (dotted in Fig. 3) can be loaded into the drum 12.

Fig. 3 and 4 illustrate only the details of the press which contribute to the invention.

On the inner lateral side of the drum 12 are provided three equal filter channels 16 (such number can vary with the type of press), on whose perforated meshes stops the solid part of the crushed material 18 while the liquid can leave the drum 12 through the relative draining openings 24, 25, 26 pushed by the pressure of an inflatable membrane 20. This arrangement, which may have a different number of draining openings, it is already known in the art.

On the openings 24, 26 according to the invention there are mounted valve means 34, 36 (e.g. slide valves) controlled by (see arrows in Fig. 4) a processing unit 60, for example a PLC.

In general, for n draining openings there are mounted m valve means on the majority of them (n>m or n≥m), in order to be able to close them on command. The closing/opening of the openings 24, 26 can however take place through manual systems as well (plugs or manually operated valves).

Under the drum 12 is a recovery basin 40 for the must 18, on whose bottom a pump 42 suctions. The pump 42 directs the flow of must/juice to a diverter assembly composed of two valves 44, 46, controlled by the unit 60, too (see arrows).

The valves 44, 46 serve to guide the flow of must either to a tank of "flower" must 50 or to a tank 48 of less valuable must called "second pressing" or "pressed".

The press generally works with the following method. After introducing the crushed material or the grapes in the drum 12 and after closing the hatch 14, the unit 60 commands:

- The closure of the majority of the draining openings by closing the valves 34, 36;

- The opening of the valve 46; - The closure of the valve 44.

Then it commands the inflation (in known manner) of the membrane 20 thereby making the first quality-must drain.

Considering (Fig. 3) a small volume 21 of must 18, one can note that in order to exit it is forced on a path 22, much longer than the path 24 which it would have travelled if the valve 36 was open. Thus, on the average the must 18 leaving from the opening 25 with the valves 34, 36 closed is more pure, because it was sifted to a greater extent by a thicker layer of marc. The must or liquid leaves the drum 12, falls into the basin 40 and is pumped into the tank 50.

Then the unit 60 commands the draining openings 24, 26 to be all open, here through the valves 34, 36, and reverses the state of the valves 44, 46. During the next pressing phase some less valuable must is extracted by all the openings 24, 25, 26 and is pumped in the tank "pressed" 48.

In fig. 2 is shown in detail a particularly favorable pressing cycle because it reduces the number of marc Grumblings and consequently the marc is torn only slightly. The cycle is managed by the unit 60.

The pressure of the membrane 20 is increased with a stepped course 80 over time. It reaches quickly a value of roughly P1 = 0.3 bar and stays at this value for approximately a time T1 = 30 minutes. Then it goes up approximately to a value P2 = 0.6 bar and there it remains for a time approximately T2 = 30 minutes. Then the membrane 20 is deflated, the drum 12 is rotated to crumble the mass of compacted marc, which remains at rest for a time approximately T3 = 1 minute or 60 minutes, and then again the cycle goes on with two other steps of pressure. The stepped pressure course can be repeated over time, even with different stable pressure values and/or different numbers of steps and/or different frequency and duration of the crumbling phases.

Claims

1. Pressing method for an animal or vegetable product, for example grapes or crushed material, after its loading inside the drum (12) of a pneumatic press (10), the drum being equipped with an inflatable, inner pressing membrane (20) and with two or more drainage outlets (24, 25, 26 ) of juice or liquid of the product, characterized by the phases of (i) leaving open only a subset (25) of said outlets; (ii) pressing the product by inflating the membrane; (iii) opening a higher number (24, 26) of said outlets, eventually all; (iv) pressing again the product by inflating the membrane.

2. Method according to claim 1 , wherein in the phase (i) said subset is a minority of said outlets, preferably one third.

3. Method according to claim 1 , wherein in the phase (i) only one outlet (25) is left open.

4. Method according to any of the preceding claims, wherein the stage (iii) occurs only after one pressing movement of the membrane.

5. Method according to any of the preceding claims, wherein the pressure of the pressing membrane is increased with a stepped increasing course (80).

6. Method according to claim 5, wherein a stepped increasing course for the membrane pressure is alternated with a return thereof to about zero contemporarily with one or more rotations of the drum to crumble the squeezed product.

7. Method according to claim 6, wherein the stepped increasing pressure course comprises the temporarily constant values of about 0.3 bar (T1) and/or 0.6 bar (T2).

8. Method according to claim 6 or 7, wherein the one or more rotations of the drum take place in or before an idle period for the press, preferably of about one minute (T3).

9. Pneumatic press (10) for pressing an animal or vegetable product, for example grapes or crushed material, comprising a drum (12), for loading the product therein, equipped inside with an inflatable pressing membrane (10) and with two or more drainage outlets (24, 25, 26) for liquid or juice of the product, characterized by comprising means (34, 36) destined to selectively close a subset of said outlets (24, 26) during an initial pressing phase.

10. Pneumatic press according to claim 9, wherein said means destined to close comprise valve means (34, 36).

11. Pneumatic press according to claim 9 or 10, comprising a processing unit (60) arranged to control the means destined to close (34, 36).

12. Pneumatic press according to claim 11 , wherein the processing unit is configured to leave open only one outlet (25) or a minority of the outlets during an initial pressing phase.

13. Pneumatic press according to any of the claims 9 to 12, comprising a liquid- or juice flow diverter assembly to discriminate the liquid or juice coming out from the drum during and/or after the initial pressing phase to at least two distinct conveyance circuits (44 , 46, 48, 50).

14. Pneumatic press according to claim 13, wherein the assembly comprises valve means (44, 46) adapted to close/open in the diverter assembly at least one outlet for the liquid or juice so that at least one outlet is open when the remaining outlets are closed and vice versa.

15. Pneumatic press according to claim 14, wherein the processing unit is configured to manage the open/closed condition of the valve means (44, 46).