ITRE20120094A1 - PRESSING DEVICE AND ITS OPERATING METHOD - Google Patents

Description

DESCRIPTION

â € œPRESSING DEVICE AND RELATIVE METHOD

OF OPERATIONâ €

The present invention relates to a device for the continuous pressing of products containing a solid part and a liquid part, and the relative method of operation.

In particular, the device and the method of the present invention are directed to the pressing of vegetable products, typically to the pressing of grapes in the oenological field, without however excluding that they can be advantageously used also for the pressing of other products, including organic waste. of animal breeding or other pulps of various kinds in which it is however necessary to separate the liquid part from the solid one.

As is known, the oenological processes require that the bunches of grapes coming from the harvest are subjected to an initial pressing phase, which has the function of breaking and crushing the berries, in order to obtain a product containing juice (must) , skins, seeds, pulp residues and even stalks, if the latter have not been completely eliminated with a preliminary de-stemming phase.

The product obtained from the pressing is then subjected to a pressing phase which has the purpose of separating the liquid part, that is the must, from the solid parts such as the skins, the seeds and the stalks.

This pressing phase can be carried out by means of discontinuous oenological presses which include a pressing element, for example a sliding piston or an inflatable membrane, which is able to press the product inside a chamber with a perforated wall, so that the must obtained from this pressing comes out of the holes in the walls while the solid parts remain contained inside.

Normally the product to be processed is pressed several times, following each pressing phase with a mixing phase, in which the solid parts are mixed inside the press chamber in order to obtain a more complete exhaustion of the berries.

In principle, the must obtained with the first pressing stages is more valuable and therefore used for higher quality products than that obtained from the subsequent pressing stages.

Once the complete exhaustion of the berries has been reached, the completely squeezed solid parts (pomace) are discharged from the press chamber, which is then filled with new product to be processed.

Although effective and functional, this type of press has the disadvantage of being able to operate only discontinuously, which significantly limits its production capacity.

To cope with this drawback, continuous cycle wine presses have been proposed, the most common of which include a perforated cylinder in which a rotating screw is housed.

The product to be processed is loaded from an inlet located at a first end of the perforated cylinder, and is made to advance by the auger towards an outlet located at the opposite end. The auger normally has a variable pitch which decreases from the inlet towards the outlet, so as to subject the product to increasing compression as it advances along the perforated cylinder.

The must obtained from this progressive pressing continuously comes out from the perforated walls of the cylinder while the exhausted pomace is continuously discharged through the outlet.

Since the quality of the must obtained with this system is generally better near the inlet and progressively decreases towards the outlet, it is usually collected in a tank located below the perforated cylinder and divided into sectors suitable for keep the different qualities of must separate.

Thanks to this continuous cycle operation, screw presses have the important advantage of having a greater production capacity compared to discontinuous presses.

On the other hand, continuous presses involve a certain difficulty in adapting the pressing parameters, especially the squeezing pressure, to the changing conditions of the product to be processed. Furthermore, continuous presses often subject the grapes to strong mechanical stresses, deriving from contact with the moving auger, which can give rise to unwanted lees caused for example by the partial destruction of the skins, or even the breaking of the pips and stalks, with the possible release of unwanted substances.

An object of the present invention is therefore to provide a pressing device that is not affected by the drawbacks of the known art, thanks to which it is possible to perform an effective continuous cycle pressing, which allows an adequate adjustment of the pressing parameters in based on the characteristics of the product to be processed, and that it does not subject the product to excessive mechanical stress.

A further object of the present invention is to achieve the aforementioned objective within the framework of a simple, rational and relatively low cost solution.

These and other objects are achieved thanks to the characteristics of the invention which are reported in the independent claims. The dependent claims outline preferred or particularly advantageous aspects of the invention.

In particular, the present invention makes available a device for the continuous pressing of products comprising at least a liquid part and a solid part, in particular for vegetable products such as grapes, which comprises:

- a tubular body with at least partially perforated side wall, - a piston slidably inserted in a first end of the tubular body,

- at least one inlet associated with the piston and leading into a pressing chamber defined inside the tubular body between the piston and the second axial end of the tubular body itself, - a pump connected to said inlet to feed the product to be press inside the bale chamber, e

- shutter means to oppose the product coming out from the second axial end of the tubular body, said shutter means being movable between a position of complete closure of the pressing chamber, in which they prevent the product from coming out, and a position of complete opening of the chamber of pressing, in which they allow the product to come out freely.

As will become clear in the following, thanks to this solution it is advantageously possible to carry out an effective continuous cycle pressing process of the product to be pressed, for example grapes, without using any rotating screw inside the pressing chamber, and therefore reducing the risk of destruction and breakage of the solid parts of the product, such as the skins, pips and grape stalks.

According to an aspect of the invention, the shutter means can comprise a swing door hinged at the second axial end of the tubular body.

Thanks to this solution, the door in the completely closed position is coupled with the extremity of the tubular body, completely closing the pressing chamber and the product to be processed inside it. Rotating outwards, the door tilts and moves away from the end of the tubular body, defining a discharge port through which the product contained in the bale chamber can exit outside. The dimensions of this exhaust port increase as the inclination of the door increases with respect to the axis of the tubular body. The door arrives in the fully open position when it reaches parallelism with the axis of the tubular body, that is when it leaves the cross section of the tubular body completely clear. In each intermediate position between the fully closed and fully open position, the door continues to exert a certain contrasting action at the product outlet, which however decreases as the size of the discharge port increases.

The face of the door which faces inside the bale chamber (when the door is in the completely closed position) can be perfectly flat, or it can be shaped in order to improve the shape of the discharge port. For example, the aforesaid face of the door can be rounded, or it can be cone-shaped, wedge-shaped or more generally it can be defined by one or more inclined surfaces that protrude inside the bale chamber.

According to an alternative embodiment, the shutter means can comprise a further piston which can be slidably inserted into the second axial end in the tubular body.

In this way, when the piston is at least partially inserted in the second end of the tubular body, the pressing chamber is completely closed. Retracting towards the outside, the piston distances itself from the second end of the tubular body, creating an exhaust port for the product outlet. However, the piston continues to exert a certain contrasting action at the product outlet. This contrasting action decreases as the distance between the piston and the tubular body increases, or as the size of the exhaust port increases, until it reaches a position of complete opening in which the piston is so far from the tubular body that the product coming out from the second end of the latter is no longer able to reach it. Also in this case, the face of the piston facing the inside of the bale chamber can be perfectly flat, or it can be shaped in such a way as to improve the shape of the discharge port, for example it can have a rounded, cone, wedge or in general be defined by one or more inclined surfaces that extend inwards.

According to another aspect of the invention, the pump can be a peristaltic pump.

A peristaltic pump is generally a volumetric pump with adjustable flow rate that applies the principle of peristalsis, according to which the product to be pumped is pushed towards the delivery by a restriction that runs along an elastic tube. The use of a peristaltic pump is particularly advantageous for this type of applications, as it does not involve direct contact between the product to be processed and the rotating parts of the pump. However, it is not excluded that the peristaltic pump can be replaced by other types of volumetric pumps with adjustable flow rate.

According to another aspect of the invention, the device can comprise a scraper cylinder, which is coaxially interposed between the piston and the tubular body and is movable with respect to both with reciprocating motion, typically between a rear position in which it is substantially flush with the piston and an advanced position in which it protrudes axially with respect to the piston towards the inside of the bale chamber.

The presence of this scraper cylinder is important to be able to periodically clean at least a part of the perforated wall of the tubular body, the holes of which tend to be blocked by the product being pressed, hindering and sometimes making it completely impossible to drain the must.

The present invention then makes available an operating method for the device outlined above, which comprises a start-up phase which provides for:

- arrange the shutter means in the completely closed position, - start the pump in order to load the pressing chamber, forming a compact agglomerate of pressed product (called a buffer) in correspondence with the second axial end of the tubular body,

- moving the shutter means to a position of at least partial opening of the bale chamber,

and then a subsequent continuous cycle pressing phase which involves:

- keep the pump running constantly, in order to continuously feed the product to be pressed into the pressing chamber and consequently cause the progressive release of the pressed product from the second end of the tubular body.

Thanks to the start-up phase, when the shutter means are opened, the product loaded into the pressing chamber does not come out freely, but is held inside by the friction that the pressed product pad exerts against the lateral walls of the tubular body, possibly assisted by the contrasting action that the obturator means in the partially open position can continue to exert on the pad itself.

In this way, during the subsequent continuous cycle pressing phase, the product to be pressed, which is continuously delivered into the pressing chamber by the volumetric pump, pushes the product already present to flow axially towards the second end of the tubular body. This thrust implies that the end part of the pad comes out and is discharged outside the pressing chamber, while the product already present in the chamber is progressively compacted towards the discharge reforming the discharged portion of the pad, and while the product just introduced begins to be squeezed in the initial section immediately downstream of the piston. Since the delivery of the product by the pump is continuous, the overall effect obtained is therefore that of a continuous pressing of the product, with the liquid part (for example the must) continuously coming out from the perforated walls of the tubular body, and with the solid parts completely pressed (for example the pomace) which are continuously discharged through the second end of the tubular body.

This pressing is carried out in total absence of mechanical actions, only due to the pressure feeding of the product to be processed inside the pressing chamber.

The degree of pressing to which the product is subjected is also generally increasing axially towards the pad, so the quality of the liquid part (e.g. must) obtained with this system is usually better near the piston and progressively decreases. towards the second end of the tubular body, allowing for separate collection.

According to a preferred aspect of the invention, the step of loading the pressing chamber provides in particular for:

- set the piston in an initial position inside the tubular body,

- monitor the pressure in the pressing chamber until a predetermined value is reached, and then

- progressively move the piston towards the first end of the tubular body until reaching a predetermined working position. In this way, the start-up phase makes it possible to immediately create a rather dense pad of completely pressed solid parts (eg marc) at the second axial end of the tubular body.

To obtain this effect, the piston can be kept in the initial position until the pressure in the bale chamber reaches a rather large value, for example between 2 and 8 bar, in order to ensure that the solid parts of the pad have a quite high degree of compactness for the subsequent phases.

By progressively withdrawing the piston towards the first end of the tubular body, the length of the pressing chamber is then increased until the pre-established working position is reached for the subsequent continuous cycle pressing phase.

The working position of the piston generally depends on the characteristics of the product to be pressed and the type of processing. In principle, this position is established so that the final length of the pressing chamber is sufficiently high to obtain, in the continuous cycle pressing phase, the complete exhaustion of the product to be pressed (i.e. a substantially complete squeezing of the solid parts ), but not so high as to cause excessive tampon consolidation.

By progressively withdrawing the piston, a progressive differentiation of the characteristics of the product that accumulates inside the pressing chamber is also obtained, ie more solid and compact towards the obturator means and progressively more liquid and less compact towards the piston.

Going into more detail, the bale chamber loading phase may involve moving the piston towards the working position by a predetermined pitch, for example between 30 and 300 mm, whenever the pressure inside the bale chamber reaches a predetermined value, for example a value between 2 and 8 bar.

This retreat by successive steps is advantageous as it has proved to be particularly effective for consolidating the pad and for axially differentiating the degree of compaction of the product that gradually accumulates in the tubular body.

According to another aspect of the invention, the continuous cycle pressing step provides for:

- monitor the pressure in the bale chamber, e

- adjusting at least one operating parameter of the device so as to maintain a predetermined value of the pressure in the pressing chamber, for example between 2 and 8 bar.

By keeping the pressure in the pressing chamber substantially constant, it is advantageously possible to preserve the dynamic balance which allows to constantly recreate a quantity of buffer equal to that discharged in the same period, avoiding both an excessive consolidation of the buffer, which could result in the locking of the device , and an excessive softening of the same, which could cause its breakage and therefore the immediate emptying of the pressing chamber.

According to a preferred aspect of the invention, the operating parameter which is adjusted to maintain the desired pressure is selected from: the position of the shutter means, the pump supply flow rate and the position of the piston.

This choice is advantageous as these parameters are the ones that usually influence the buffer equilibrium the most and therefore the pressure in the bale chamber.

In particular, an embodiment of the invention provides for the possibility of regulating all these operating parameters, possibly sequentially one after the other.

For example, if the pressure in the pressing chamber drops (it means that the pad is softening), the method can provide for: 'exit of the buffer and therefore the counter-pressure acting on it,

- reduce the flow rate of the feed pump, in order to increase the compaction of the solid parts (marc) that form the buffer,

- move the piston towards the first end of the tubular body, so as to increase the length of the pressing chamber and consequently increase the exhaustion of the solid parts (marc) that form the buffer.

If all these interventions do not have the effect of increasing the pressure in the pressing chamber up to the predetermined value, it is possible to bring the shutter means to the completely closed position and repeat the start-up phase of the device. If, on the other hand, the pressure in the pressing chamber increases (it means that the pad is hardening), the method can include:

- move the obturator means towards the fully open position, so as to reduce the contrasting action at the exit of the plug and therefore the back pressure acting on it,

- increase the flow rate of the feed pump, in order to reduce the compaction of the solid parts (marc) that form the buffer,

- move the piston towards the second end of the tubular body, in order to reduce the length of the pressing chamber and consequently reduce the exhaustion of the solid parts (marc) that form the buffer.

If all these interventions do not have the effect of lowering the pressure in the bale chamber to the predetermined value, it is possible to carry out an unlocking procedure which consists in pushing hard the hardened pad towards the discharge.

This operation can be performed by advancing the piston towards the second end of the tubular body by successive steps, individually comprised, for example, between 30 and 300 mm. At the end of each step it is possible to check the conditions and if the ideal conditions have not been restored, proceed with a further push step.

It should be noted that although the main parameter to be controlled is the pressure in the bale chamber, the method could also provide for the control of other process parameters, such as the thrust exerted by the plug on the shutter means and / or the flow rate of the liquid part ( must) collection (also differentiated).

Another aspect of the invention provides that the continuous cycle pressing step can also include:

- make the piston perform an alternative movement starting from the working position.

This operation can be repeated continuously one or more times with a predetermined periodic frequency.

In this way, during the retraction stroke towards the first end of the tubular body, the pressing chamber expands and a suction effect is obtained which is added to the pump delivery, favoring the delivery of the product to be pressed. On the other hand, during the advancement stroke towards the second end of the tubular body, a compression effect is obtained. In this way, the forward stroke of the piston contributes to the advancement of the whole plug and, thanks to the scraping of the piston seal rings against the side wall of the tubular body, to remove the product that could clog the drainage holes that found in the first section of the pressing chamber and which are essential for the recovery of the must.

The piston stroke during these operations can have a predetermined length between 30 and 300 mm starting from the working position for the continuous cycle pressing phase.

If the device is equipped with the previously mentioned scraper cylinder, the cleaning phase of the drainage holes can also be carried out by activating the scraper cylinder to move with respect to the tubular body and the piston which remain stationary.

According to another aspect of the invention, the continuous cycle pressing step can provide for modifying the position of the piston on the basis of a variation in the characteristics of the product to be pressed.

This aspect of the invention has the advantage of adapting the operation of the device to a variation in the characteristics of the product to be processed, without interrupting the continuous cycle pressing step.

A further aspect of the invention provides that the method of operation also includes an end-of-work phase which provides for:

- stop the operation of the pump,

- bring the shutter means to the fully closed position,

- move the piston towards the second end of the tubular body by applying a constant thrust of a predetermined value.

In this way a static pressing is carried out which has the effect of completely exhausting the product still contained in the pressing chamber, retaining only the exhausted solid parts (pomace).

Preferably, the thrust applied to the piston must be such that the latter exerts a constant pressure on the product equal to the ideal pressure foreseen for continuous cycle pressing.

According to another aspect of the invention, the stage of final processing also provides for:

- monitor the displacement of the piston while it is subjected to said thrust and, when the monitored displacement of the piston is zero, - move the shutter means to the fully open position of the bale chamber and

- make the piston advance further towards the second end of the tubular body.

Thanks to this solution, once the residual product is completely exhausted, it is definitively and completely discharged outside the tubular body.

A further aspect of the invention provides that, during the phase of final processing, the piston is made to advance until it is completely external to the pressing chamber, simultaneously leaving the second end of the tubular body open.

In this way, after having been emptied of completely exhausted solid parts (pomace), it is easily possible to carry out a complete internal cleaning and sanitization of the pressing chamber, as well as of the piston and the relative scraper cylinder (if present).

This is a great advantage over screw presses which cannot be cleaned and cannot easily restart from empty.

Finally, the invention makes available a pressing apparatus which comprises the device outlined above and an electronic control system, which is programmed in such a way as to carry out the above-described steps of the relative operating method.

Further characteristics and advantages of the invention will become evident by reading the following description provided by way of non-limiting example, with the aid of the figures illustrated in the attached tables.

Figure 1 is a perspective view of a press according to an embodiment of the present invention.

Figure 2 is a side view of the press of Figure 1.

Figure 3 is a top view of a loading piston belonging to the press of Figure 1, shown with the scraper cylinder in section and in retracted position.

Figure 4 is the view of Figure 3 shown with the scraper cylinder in the forward position.

Figure 5 is a schematic side view of a pressing device according to an embodiment of the present invention, in which the press is shown in section.

Figures 6 to 10 show the device of Figure 5 in as many operating phases of the pressing process.

Figure 5 illustrates a device 100 for the continuous cycle pressing of food products, in this case for pressing grapes in the oenological field.

The device 100 schematically comprises a pump 200 adapted to take the product to be pressed from a crusher 300 and to feed it under pressure inside a press 400.

The crusher 300 is a device capable of processing whole, de-stemmed or partially de-stemmed bunches of grapes, in order to open and crush the berries, in order to obtain a product containing a liquid part (must) and a solid part (skins , grape seeds, pulp residues and even stalks, if the latter have not been completely eliminated with a preliminary de-stemming phase).

The crusher 300 can generally comprise a loading hopper 305, through which the product to be crushed is conveyed between two counter-rotating grooved rollers 310, which have the function of breaking and crushing the grapes. The product that passes through the grooved rollers 310 is collected in a lower tank 315, inside which an auger 320 is received. The auger 320 is driven by an electric motor 325 positioned outside the tank 315, so as to advance the pressed product towards the pump 200.

In some embodiments it is possible to provide that between the crusher 300 and the pump 200 a draining device (not shown) is interposed, for example a vibrating grid drainer, for the separation of the liquid from the solid parts of the grapes and fermented marc. .

Pump 200 is generally a volumetric pump with adjustable flow rate. In the example shown, Pump 200 is a peristaltic pump. In particular, the pump 200 comprises a flexible and elastic tube 205, for example made of silicone, PVC or other polymers, the ends of which define respectively the inlet 210 and the outlet 215 of the pump. The pump 200 further comprises a rotor 220, which is rotationally driven by a respective motor (not shown). The rotor 220 carries two diametrical rollers 225, which are able to roll in contact with the flexible tube 205, so as to define a constriction which moves along the length of the tube itself. In this way, discrete quantities of product are continuously pushed by the restriction from the inlet 210 towards the outlet 215. The flow rate of the pump 200 can be adjusted by varying the rotation speed of the rotor 220 by means of the motor.

The use of the peristaltic pump 200 is advantageous as the pumping takes place without direct contact between the product and the moving parts of the pump. However, it is not excluded that, in other embodiments, the peristaltic pump 200 can be replaced by a volumetric pump of any other type, provided it has an adjustable flow rate.

The press 400 comprises a tubular body 405, in this case an internally hollow cylinder. The tubular body 405 is supported by a support frame 410, in this case by a trolley, on which the tubular body 405 is preferably arranged with its own X axis oriented horizontally. The side wall of the tubular body 405 is perforated, ie it has a multiplicity of through-holes for drainage.

In the example shown, these drainage holes are uniformly distributed over the entire side wall of the tubular body 405, but it is not excluded that in other embodiments they may be distributed over a limited part of the side wall, for example only on the lower part. .

The tubular body 405 has two axial ends, of which a first end on the load side and a second end on the unloading side. A loading nozzle 415 and a discharge nozzle 420 are respectively coaxially fixed to these ends, which have substantially the same diameter as the tubular body 405. The loading nozzle 415 is perfectly cylindrical, while the discharge nozzle 420 is cut. like a flute.

To the discharge nozzle 420 are associated shutter means, indicated as a whole with 425, which are able to completely close the second axial end of the tubular body 405 and to open it progressively, continuing to exert a contrast action against the outlet. of the product, until it reaches a position of complete opening, in which the product can come out freely from the tubular body 405.

In the example illustrated, the shutter means 425 comprise a door 430, which is hinged to the discharge nozzle 420 according to an axis of rotation Y perpendicular to the axis X of the tubular body 405. The axis of rotation Y is positioned in proximity to the second axial end of the tubular body 405, but outside the cross section of the latter. In this way, in the completely closed position, the door 430 obstructs the discharge spout 420 (see fig. 6), completely closing the second axial end of the tubular body 405. Rotating outwards, the door tilts and moves away. from the edge of the tubular body 405, rising with respect to the lower wall of the discharge nozzle 420. In this way, the door 430 progressively defines a discharge port through which the product contained in the tubular body 405 can exit outside, meeting more or less resistance depending on the size of the exhaust port itself. In particular, the dimensions of the discharge port increase progressively until the door 430 reaches the raised position shown in figure 5. In this position, the door 430 is substantially parallel to the X axis of the tubular body 405, leaving the door completely free. its cross section and therefore allowing the product to escape without any obstacle.

It should be noted that, to improve the shape of the discharge port, the face of the door 430 which faces the outgoing product, has a convex profile which protrudes towards the inside of the tubular body 405 (when the door is in fully closed position). However, it is not excluded that in other embodiments, this face of the door 430 may be perfectly flat or may be shaped like a cone, wedge or in general with inclined walls.

The displacements of the door 430 between the aforementioned fully closed and fully open positions are delegated to a cylinder / piston 435 unit, hydraulically operated and double-acting, the ends of which are hinged respectively to a horizontal support 440 fixed above the body. tubular 405, and to a pair of brackets 445 fixed to the door 430 and rotating integrally with it around the Y axis in the manner of a rocker arm. In this way, the lengthening and shortening of the cylinder / piston assembly 435 allows the door 430 to be moved and stopped in the fully closed, fully open positions and in any intermediate position.

As illustrated in Figure 1, the loading nozzle 415 and the unloading nozzle 420 are fixed to two longitudinal members 450, which are parallel and positioned on diametrically opposite parts of the tubular body 405. The longitudinal members 450 project axially with respect to the loading nozzle 415 , on the opposite side with respect to the tubular body 405, so as to act as guides for a slide 455. In the illustrated example, the slide 455 comprises a central body 460 interposed between the longitudinal members 450, and two roller shoes 465 fixed to the central body 460 and individually coupled in sliding to a respective side member 450. In this way, the slide 455 is able to slide on the side members 450 in the direction of the X axis of the tubular body 405, towards and away from the loading nozzle 415. displacements of the slide 455 are delegated to two long-stroke cylinder / piston groups 470, hydraulically operated and double-acting, each of which is fixed to a resp longitudinal member 450 while the end of its own piston 475 is fixed to a respective roller shoe 465. A load group is integrally fixed to the central body 460 of the slide 455, indicated globally with 480 and visible in detail in figures 3 and 4. The load group 480 comprises a piston 485, generally cylindrical in shape, which is placed at the end of a coaxial shaft 490 (partially visible in figure 1), whose opposite end is fixed to the central body 460 of the slide 455, so that the piston 485 is able to slide solidly with the latter along the X axis of the tubular body 405. In the example illustrated, the piston 485 is coaxially inserted in a scraper cylinder 495 having a greater axial length to that of the piston 485. The scraper cylinder 495 is carried to the end of a cylindrical jacket 500 (partially visible in figure 1) which is slidably inserted on the shaft 490. In this way, the scraper cylinder 495 is able to move integrally with the slide 455, but it is also able to move independently on board the slide 455 in the direction of the X axis of the tubular body 405, between a rear position shown in figure 3 , in which its end is substantially flush with the extremal face of the piston 485, and an advanced position shown in figure 4, in which its end exceeds the extremal face of the piston 485. This movement of the scraper cylinder 495 is required with two cylinder / piston groups 505, hydraulically operated and double-acting, the ends of each of which are respectively fixed to the central body 460 of the slide 455 and to a respective rib protruding from the cylindrical jacket 500.

As illustrated in Figure 5, the piston 485 and the scraper cylinder 495 pass through the loading nozzle 415 and are coaxially and slidingly inserted to size in the tubular body 405, so as to close the first end thereof. This closure is made hermetic by one or more sealing rings which are applied to the skirt of the piston 485, so as to be coaxially interposed between the latter and the scraper cylinder 495, and by one or more sealing rings which are applied on the scraper cylinder 495, so as to be coaxially interposed between the latter and the tubular body 405.

It should be noted that in other embodiments the scraper cylinder 495 may not be present, in which case the piston 485 will be sized to occupy by itself the entire cross section of the tubular body 405 with the interposition of one or more sealing rings .

In any case, between the extremal face of the piston 485 and the second end of the tubular body 405 a pressing chamber 510 with a perforated wall remains defined. Said bale chamber 510 can be completely closed, partially open or completely open according to the position of the door 430, while its internal volume is variable according to the axial position occupied by the piston 485.

The loading unit 480 finally includes a feeding tube 515 for the product to be pressed, which is eccentrically positioned above the shaft 490 and is integral with the slide 455. A first end of this feeding tube 515 is connected to the outlet 215 of the pump 200 through a flexible duct 520, or in any case an extendable duct so as to be able to accommodate the displacements of the slide 455. The second end of the supply tube 515 is coupled to a delivery mouth 525, the which is obtained in the body of the piston 485 and flows into the pressing chamber 510 through the extremal face of the piston itself.

Below the tubular body 405, the device 100 is provided with a collection tank 530 for the must obtained from pressing. The tank 530 extends along the entire length of the tubular body 405 and can be internally divided into sectors by a plurality of bulkheads 535 arranged in succession along its length. Each of these sectors can be associated with a relative discharge duct 540 for collecting the must.

The device 100 is finally completed by an electronic control system (not shown), which generally comprises at least one electronic processing unit connected to the various hydraulic actuators and to the electric motors of the pump 200 and of the crusher 300, which is It is programmed to carry out the steps of the operating method which are described below.

In principle, the method of operation of the device 100 provides for a start-up phase, a pressing phase in a continuous cycle and a subsequent finishing phase.

With reference to figure 6, the start-up phase envisages first of all arranging the door 430 in the position of complete closure of the pressing chamber 510, and then bringing the piston 485 close to the door 430 until reaching an initial position in which it is the most possible proximal to the second end of the tubular body 405, ie a position in which the volume of the bale chamber 510 is minimum.

Starting from this configuration, the start-up phase involves putting into operation the crusher 300 and the pump 200, so that the crushed product begins and is fed into the pressing chamber 510. In this way, the must flows from the perforated walls of the tubular body 405, while the solid parts of the product gradually thicken and compact against the door 430, starting to form a rather dense agglomerate which takes the name of buffer.

During this buffer formation phase, the method provides that the pump 200 is operated at a constant flow rate, keeping the pressure in the bale chamber 510 monitored, i.e. the pressure with which the pump 200 pushes the product into the bale chamber 510.

This pressure can be measured directly, for example by means of special pressure sensors placed in the pressing chamber 510 or in the connection ducts 515 and 520, or it can be measured indirectly, for example by measuring the value of the torque delivered by the electric motor. to rotate the rotor 220 of the pump 200, or by measuring the thrust exerted by the product against the door 430.

When the pressure in the bale chamber 510 reaches a preset value, for example a value between 2 and 8 bar, it means that the pad is sufficiently compact.

Upon reaching this condition, the start-up phase therefore provides for the piston 485 to perform a retreat step towards the first end of the tubular body 405, always keeping the pump 200 running at a constant flow rate. This retraction step can be equal to a predetermined distance, for example between 30 and 300 mm. In this way, the volume of the bale chamber 510 increases while the pressure decreases.

Always keeping the pump 200 running at a constant flow rate, the start-up phase then provides for the piston 485 to perform a further retraction step each time the pressure in the pressing chamber 510 reaches the preset value again. In this way, a progressive retraction of the piston 485 and a progressive increase in the length of the pressing chamber 510 are obtained, thanks to which it is advantageously possible to consolidate the pad and axially differentiate the degree of compaction of the product which gradually becomes accumulates in the tubular body 405. In practice, it is obtained that the solid part of the grapes accumulated in the pressing chamber 510 is more solid and compact towards the door 430 and progressively more liquid and less compact towards the piston 485 (see figure 7) .

The retraction of the piston 485 ends when it reaches a predetermined working position for the subsequent pressing step in a continuous cycle. The working position of the piston 485 generally depends on the characteristics of the product to be pressed and on the type of processing. In principle, this position is established so that the final length of the pressing chamber 510 is sufficiently high to obtain, during the continuous cycle pressing phase, the complete exhaustion of the product to be pressed (i.e. a substantially complete squeezing of the parts solid), but not so high as to cause excessive tampon consolidation.

When the piston 485 reaches the predetermined working position, the pump 200 is kept running at a constant flow rate, with the door 430 still in the completely closed position, until the pressure in the bale chamber 510 reaches the preset value again, after whereupon the start-up phase ends with the complete or at least partial opening of the door 430, thereby also starting the continuous cycle pressing phase (see figure 8).

When the door 430 is opened, the product that is already contained in the pressing chamber 510 cannot come out freely, but is held inside by the friction that the squeezed pomace pad exerts against the side walls of the tubular body 405, possibly assisted by the contrasting action that the door 430 in the partially open position can continue to exert on the pad itself.

Thanks to the presence of the pad, during the subsequent continuous cycle pressing phase, the door 430 is then kept in a position of complete or partial opening and the pump 200 is kept constantly running, so as to continuously feed the product to be press inside the bale chamber 510.

In doing so, the product to be pressed which is continuously dispensed into the pressing chamber 510 through the dispensing mouth 525 pushes the product already present to flow axially towards the second end of the tubular body 405. This thrust implies that the terminal part of the the buffer comes out and is discharged outside the pressing chamber 510, while the solid part of the product already present in the chamber is progressively compacted towards the discharge, reforming the discharged portion of the buffer, and while the product just introduced is squeezed in the initial section immediately to valley of the piston 485.

The overall effect obtained is therefore that of a continuous pressing of the product, performed in the total absence of mechanical actions and only due to the pressure feeding of the product to be processed inside the pressing chamber 510, with the must that it continuously exits from the perforated walls of the tubular body 405 and with the exhausted marc which is progressively discharged through the discharge nozzle 420.

The degree of pressing to which the solid part of the product is subjected is generally increasing axially towards the discharge spout 420, so the quality of the must obtained with this system is usually better near the piston 485 and progressively decreases. towards the second end of the tubular body 405, thus allowing separate collection within the various sectors of the underlying collection tank 530.

To maintain the dynamic balance that allows to constantly recreate a quantity of buffer substantially equal to that discharged in the same period, it is preferable to ensure that the pressure in the pressing chamber 510 remains constantly equal to a predetermined value for the entire duration. of the continuous cycle pressing phase, and for example equal to a value between 2 and 8 bar.

To achieve this purpose, during the continuous cycle pressing phase, the method provides for continuing to monitor the pressure in the pressing chamber 510, and therefore for regulating in a closed cycle at least one operating parameter of the device 100, so as to minimize the error between the measured pressure value and the predetermined one.

In particular, the method provides for simultaneously or sequentially adjusting the position of the door 430, the feed flow rate of the pump 200 (for example by adjusting the speed of the rotor 220), and the working position of the piston 485.

For example, if during the continuous cycle pressing the pressure in the pressing chamber 510 drops (it means that the pad is softening), the method can foresee:

- move the door 430 towards the completely closed position, so as to reduce the size of the discharge port and therefore increase the counter pressure acting on the outlet plug,

- reduce the flow rate of pump 200, in order to increase the time available for compacting the pomace of the buffer,

- retracting the piston 485 towards the first end of the tubular body 405, so as to increase the length of the pressing chamber 510 and consequently increase the exhaustion of the marc forming the buffer.

If all these interventions do not have the effect of increasing the pressure in the pressing chamber 510 up to the predetermined value, it is possible to bring the door 430 to the completely closed position and repeat the start-up phase of the device 100.

If, on the other hand, during the continuous cycle pressing the pressure in the pressing chamber 510 increases (it means that the pad is hardening), the method can foresee:

- move the door 430 towards the fully open position, so as to increase the size of the discharge port and therefore reduce the back pressure acting on the outlet plug,

- increase the flow rate of pump 200, in order to reduce the time available for compacting the pomace of the buffer,

- moving the piston 485 towards the second end of the tubular body 405, so as to reduce the length of the pressing chamber 510 and consequently reduce the exhaustion of the marc forming the buffer.

If all these interventions do not have the effect of reducing the pressure in the bale chamber 510 to the predetermined value, it is possible to carry out an unlocking procedure which consists in pushing the hardened pad with force towards the discharge.

This operation can be carried out by making the piston 485 advance towards the second end of the tubular body 405 by successive steps, individually comprised, for example, between 30 and 300 mm. At the end of each step it is possible to check the conditions and if the ideal conditions have not been restored, proceed with a further push step.

During the continuous cycle pressing phase, it is also possible to have the piston 485 perform from time to time, preferably integrally with the scraper cylinder 495, one or more alternative movements starting from the working position.

In this way, during the retraction stroke of the piston 485 towards the first end of the tubular body 405, the pressing chamber 510 expands and a suction effect is obtained which is added to the delivery of the pump 200, favoring the delivery of the product. to be pressed. During the advancement stroke towards the second end of the tubular body 405, on the other hand, a compression effect is obtained. In this way, the forward stroke of the piston 485 contributes to the advancement of the whole plug and, thanks to the scraping of the sealing rings of the scraper cylinder 495 against the side wall of the tubular body 405, to remove the product that could clog the holes. which are located in the first section of the pressing chamber 510 and which are fundamental for the recovery of the must.

The stroke of the piston 485 during these operations can cover a predetermined distance between 30 and 300 mm, starting from the working position for the continuous cycle pressing phase.

In order to improve the cleaning of the first section of the bale chamber 510, it is also provided that from time to time the scraper cylinder 495 is operated to reciprocate between its rearward and forward positions, in order to de-obstruct the drainage holes without move the piston 485 and therefore without changing the dimensions of the bale chamber 510.

During the continuous cycle pressing phase, it is also possible to modify the working position of the 485 piston based on a variation in the characteristics of the product to be pressed. This adjustment of the working position can be carried out manually, or automatically with the aid of suitable sensors that are able to detect the characteristics of the product being processed.

When the product to be pressed is finished, the continuous pressing phase ends and the final processing phase begins.

With reference to Figure 9, the stage of end of processing provides first of all to stop the operation of the pump 200 and to bring the door 430 to the completely closed position. After completing these operations, the phase of final processing involves moving the piston 485 towards the second end of the tubular body 405, adjusting the operation of the cylinder / piston groups 470 so that they generate a constant thrust of a predetermined value on the piston 485, preferably a value equal to the ideal value envisaged for continuous cycle pressing. In this way, a static pressing is carried out which has the effect of completely exhausting the residual product still contained in the pressing chamber 510.

While the cylinder / piston groups 470 exert the aforementioned constant thrust, the phase of end of machining also foresees the monitoring of the displacement of the piston 485. When the displacement of the piston 485 is zero, the phase of end of machining finally foresees to move the door 430 in position of complete opening of the bale chamber 510, and therefore to further advance the piston 485 towards the second end of the tubular body 405, so as to discharge the last residue of the pad outside the bale chamber 510, as well as shown in figure 10.

It is to be observed that the piston 485 is made to advance until it reaches a position in which it is so advanced as to be completely external to the pressing chamber 510, also leaving open the second end of the tubular body 405. In this way, after having been emptied of exhausted marc, the press 400 can be easily washed and sanitized. In particular, it is easily possible to carry out the complete internal cleaning of the bale chamber 510, as well as of course the piston 485 and the relative scraper cylinder 495.

Naturally, a person skilled in the art can make numerous modifications of a technical applicative nature to the device 100 described above and to the relative operating method, without thereby departing from the scope of the invention as claimed below.

Claims (15)

CLAIMS 1. A device (100) for the continuous pressing of products containing a solid part and a liquid part comprising: - a tubular body (405) with at least partially perforated side wall, - a piston (485) slidably inserted in a first end of the tubular body, - at least one inlet (525) associated with the piston (485) and leading into a pressing chamber (510) defined inside the tubular body (405) between the piston (485) and the second axial end of the tubular body ( 405) itself, - a pump (200) connected to said inlet (525) to feed the product to be pressed into the pressing chamber (510), and - obturator means (430) to oppose the product coming out from the second axial end of the tubular body (405), said obturator means (430) being movable between a position of complete closure of the pressing chamber (510), in which they prevent the product outlet, and a position of complete opening of the pressing chamber (510), in which they allow the product to come out freely. A device (100) according to claim 1, wherein the shutter means comprise a swing door (430) hinged at the second axial end of the tubular body (405). A device (100) according to claim 1, wherein the shutter means comprise a further piston which can be slidably inserted into the second axial end in the tubular body (405). A device (100) according to any one of the preceding claims, wherein said pump (200) is a peristaltic pump. 5. A device (100) according to any one of the preceding claims, comprising a scraper cylinder (495), which is coaxially interposed between the piston (485) and the tubular body (405) and is movable with respect to both with motion alternative. 6. An operating method for a device (100) according to any one of the preceding claims, comprising a start-up phase which provides for: - arrange the shutter means (430) in the completely closed position, - start up the pump (200) so as to load the bale chamber (510) forming a compact agglomerate of pressed product at the second axial end of the tubular body (405), - moving the shutter means (430) to a position of at least partial opening of the bale chamber (510), and then a subsequent continuous cycle pressing phase which involves: - keep the pump (200) running constantly, so as to continuously feed the product to be pressed into the pressing chamber (510) and consequently cause the progressive release of the pressed product from the second end of the tubular body (405 ). 7. A method according to claim 6, wherein, the step of loading the bale chamber (510) provides for: - place the piston (485) in an initial position inside the tubular body (405), - monitor the pressure in the bale chamber (510) until a predetermined value is reached, - progressively move the piston (485) towards the first end of the tubular body (405) until reaching a predetermined working position. 8. A method according to claim 7, wherein the step of loading the bale chamber (510) provides for moving the piston towards the working position by a predetermined step each time the pressure in the bale chamber (510) reaches a set point. 9. A method according to any one of claims 6 to 8, in which the continuous cycle pressing step provides for: - monitor the pressure in the bale chamber (510), e - adjusting at least one operating parameter of the device (100) so as to maintain a predetermined value of the pressure in the pressing chamber (510). 10. A method according to claim 9, wherein said operating parameter is selected from: the position of the shutter means (430), the feed flow rate of the pump (200) and the position of the piston (485). 11. A method according to any one of claims 6 to 10, wherein the continuous cycle pressing step provides for: - make the piston (485) perform an alternative movement starting from the working position. A method according to any one of claims 6 to 11, in which the continuous cycle pressing step provides for modifying the position of the piston (485) based on a variation in the characteristics of the product to be pressed. 13. A method according to any one of claims 6 to 12, comprising an end-of-work step which provides for: - stop the operation of the pump (200), - bring the shutter means (430) to the fully closed position, - move the piston (485) towards the second end of the tubular body (405) by applying a constant thrust of a predetermined value to it. 14. A method according to claim 13, in which the stage of final processing further provides for: - monitor the displacement of the piston (485) while it is subjected to said thrust and, when the monitored displacement of the piston (485) is zero, - move the shutter means (430) to the fully open position of the pressing chamber (510) e - make the piston (485) advance further towards the second end of the tubular body (405). 15. A method according to claim 14, in which the piston is advanced until it is completely external to the pressing chamber (510), leaving the second end of the tubular body (405) open.