Press for squeezing out liquid-containing substances

Abstract

Press (1) for pressing liquid-containing material, in particular grapes, with a pressure-resistant container (2), the interior of which (6) is divided by a flexible press membrane (8) into a pressure medium chamber (10) and a pressing medium chamber (12), and with at least one drainage element (20) arranged standing in the interior of the container (6) during the pressing operation, to which a juice drain (16) located in the lower area of ​​the pressing medium chamber (12) is assigned, characterized in that a ventilation valve (22) is provided in the area above the drainage element (20), through which the pressing medium chamber (12) can be supplied with ambient air.

Description

[0001] The invention relates to a press for pressing liquid-containing material, in particular grapes, according to the preamble of claim 1.

[0002] Such presses are known, for example, from EP 0 145 948 B1 and are used to press the grape juice used as a starting material for the production of wine or fruit juice from grapes or fruits filled into the press.

[0003] WO 2003035381 A1 discloses a press comprising a closed container rotatable about its horizontal longitudinal axis, in which drainage elements are arranged vertically in the filling and pressing position. These drainage elements are laterally surrounded by a pressing membrane that divides the container interior into a pressurized fluid chamber and a pressurized fluid chamber. On the top side of the pressing container, a filling and emptying opening is arranged in the container casing, which can be closed by a lid. Opposite this opening is a juice outlet located on the underside of the container, through which the liquid contained in the pressed material escapes from the container interior after the lid is closed and the press membrane is pressurized with compressed air.The drainage elements comprise an elastic or flexible support element around which a juice-permeable fabric hose is arranged, the interior of which is connected to the juice outlet in the area of ​​the lower end of the drainage element, so that the liquid pressed material can escape from the interior of the container after passing through the fabric hose during the pressing process.

[0004] The problem with the previously described press is that after the material to be pressed has been added, the filling opening has been closed, and before the actual pressing process begins, the press membrane must first be applied to the material to be pressed. This requires the air between the press membrane and the material to be pressed to be expelled from the press chamber, which can sometimes take up to half the volume of the press container. The air escapes through the juice outlet located in the lower area of ​​the press chamber, where it passes over the mash in the container or the juice in the drainage elements. This usually leads to undesirable oxidation effects that adversely affect the quality of the pressed must – and thus the quality of the resulting wine.

[0005] Similarly, after the pressing process has ended, the membrane attached to the material to be pressed is released from the material to be pressed by introducing ambient air through the juice outlet into the pressing medium chamber and moved back to the inside of the press container, whereby the ambient air also passes over the mash and the grape juice remaining in the press and leads to the previously mentioned oxidation processes.

[0006] DE 10 2004 023761 A1 describes a press for pressing liquid material, comprising a pressure-resistant container whose interior is divided into a pressure medium chamber and a pressing medium chamber by a flexible press membrane. A drainage element is arranged in the pressing medium chamber, which is positioned vertically during pressing operation and is associated with a juice drain located in the lower area of ​​the pressing medium chamber. The document does not indicate the need to provide a vent valve in the area above the drainage element, via which the pressing medium chamber can be vented after a pressing process and the renewed supply of inert gas.

[0007] From DE 69201029 T2, a similar membrane press with horizontally arranged drainage elements is known, in which the pressure medium space, i.e. the space between the inner wall of the press container and the membrane lying on the material to be pressed, which is subjected to pressurized gas during the pressing process, can be ventilated with ambient air.

[0008] From AT 62331E, a vent valve arrangement with a valve seat with a removable cover is also known, which can be opened and closed via a lever mechanism with the aid of pneumatic or hydraulic cylinders.

[0009] Another problem with the previously mentioned presses is that, depending on the amount of grape juice remaining in the drainage elements, this juice is carried along by the air flowing past as a result of the pressure build-up in the pressing medium chamber during the pressing process and escapes in the form of spray mist through the juice outlet and the subsequent juice collection line.

[0010] Regardless, the presses described above require protection against exceeding the maximum permissible overpressure in the press container, which could occur, for example, due to improper filling of the press or due to fermentation of the mash in the press container. Pressure gauges are commonly used for this purpose, which are typically located in the hollow shafts of the press, which entails additional costs and technical problems.

[0011] Alternatively, bursting discs are often used. Although they are more cost-effective and reliable than the previously mentioned pressure measuring devices, they are destroyed if the maximum permissible internal pressure in the container is exceeded and must therefore be replaced, which leads to an undesirable downtime of the press.

[0012] Accordingly, it is an object of the present invention to provide a press for pressing liquid-containing substances, in which the previously described oxidation of the liquid pressed out of the material to be pressed and the occurrence of liquid spray as a result of the air passing through the juice outlet are avoided.

[0013] This object is achieved according to the invention by the features of claim 1.

[0014] Further features of the invention are contained in the subclaims.

[0015] According to the invention, a press for pressing liquid-containing material, in particular grapes, comprises a pressure-resistant container whose interior is divided by a flexible press membrane into a pressure medium chamber and a pressing medium chamber. Preferably, several drainage elements are arranged in the interior of the container, which are oriented in a substantially vertical position during pressing operation by a corresponding rotation of the container about the container's longitudinal axis. Each drainage element is assigned a juice outlet located in the lower region of the pressing medium chamber.

[0016] The press according to the invention is characterized in that in the area above the drainage elements, i.e. in the air space above the vertically aligned drainage elements, a ventilation valve is provided, via which the pressing medium space can be supplied with ambient air.

[0017] The invention provides the advantage that the pressing medium chamber can be ventilated independently of the juice outlet after the material to be pressed has been filled in when the pressing membrane acting laterally on the material to be pressed has been applied, thereby preventing the juice already formed when the material to be pressed was filled in from being subjected to high air pressure when the membrane is applied, which leads to the vapor pressure above the juice being increased and, as a result, in particular the oxidative air components penetrating the juice to an increased extent and impairing its quality.

[0018] In the preferred embodiment of the invention, the vent valve is positioned at the uppermost point of the container in the pressing position of the press, which has the advantage that almost the entire volume of air displaced by the membrane when it is applied can escape from the container via the vent valve.

[0019] In the press according to the invention, the ventilation and venting of the entire volume in the pressing medium space not occupied by the material to be pressed preferably takes place exclusively via the ventilation valve, which has the advantage that only one valve has to be installed, cleaned and maintained.

[0020] According to a further concept underlying the invention, the vent valve comprises a continuous tube having a substantially smooth-walled, straight inner passageway devoid of any internal components. The continuous tube is preferably a nozzle that can be welded or screwed to the outside of the press container. This offers the advantage that the vent valve can be easily cleaned of press material residues that enter the tube when the press container rotates.

[0021] In the preferred embodiment of the invention, the valve comprises a pivotable closure lid that can be pivoted about a pivot axis located in the region of the nozzle in order to open or close the nozzle and thereby fluidly connect the interior of the container to the outside environment or separate it from it. The closure lid is preferably pivoted via an actuator, in particular a compressed air cylinder, and a lever mechanism, which offers the advantage that pressed material residues that accumulate in the region of the edges of the nozzle when the container rotates cannot lead to a malfunction when the closure lid is opened, as is often the case with a lid that can only be moved.

[0022] A further advantage of the pneumatically actuated closure lid is that when the maximum overpressure in the container's interior is exceeded, the venting valve automatically opens against the closing force generated by the actuator, forcing the interior of the container to be ventilated to prevent damage. Since this occurs purely mechanically, this embodiment of the invention also provides the additional function of the venting valve as a safety valve, even if the entire electrical supply to the press control system fails and the pressure in the interior of the press container increases significantly, for example, due to fermentation processes in the material being pressed.

[0023] According to a further embodiment of the invention, a pressure sensor is assigned to the interior of the container, in particular the pressure medium chamber, depending on whose signals the actuator opens or closes the ventilation valve.

[0024] The vent valve is preferably actuated by an electronic control device depending on the closed state of a juice outlet valve associated with the juice outlet, via which the juice outlet can be closed. In this embodiment of the invention, the electronic control device preferably opens the vent valve when the juice outlet valve is closed and closes the vent valve when the juice outlet valve is opened.

[0025] It can further be provided that the venting valve is opened by the electronic control device at a time delay after a pressing process to clean the valve, in particular the interior of the valve channel, of adhering material to be pressed. When the pressurized fluid chamber is subjected to negative pressure, this opens the press membrane from the material to be pressed back toward the container wall. Due to the negative pressure that develops in the pressurized fluid chamber when the juice outlet valve and venting valve are closed, any residue from the pressurized material that has accumulated in the area of ​​the sealing surfaces is sucked out after the venting valve is opened, thus ensuring trouble-free operation of the valve.

[0026] According to a further concept underlying the invention, the vent valve is housed in the lid of the press container, through which the material to be pressed is introduced into the press medium chamber. This offers the advantage that the vent valve, together with the actuator also arranged on the lid, can be moved out of the filling area of ​​the material to be pressed. In the case of a movable lid, this is preferably achieved by sliding the lid laterally along suitable guides.

[0027] The invention is described below with reference to the drawings using a preferred embodiment.

[0028] The drawings show: Fig. 1 a schematic spatial representation of a press according to the invention with the drainage elements arranged in the interior thereof, Fig. 2 a schematic cross-sectional view of the press container, Fig. 3 a schematic partial cross-sectional view of the top of the press container with the ventilation valve open, and Fig. 4 a schematic partial cross-sectional view of the top of the press container with the vent valve closed.

[0029] As in the Fig. As shown in Figures 1 to 4, a press 1 according to the invention comprises an elongated cylindrical container 2, which is rotatable about the container's longitudinal axis 4 via drive devices not shown in detail. Arranged within the container interior 6 is a press membrane 8, which is only schematically indicated for illustrative reasons and divides the container interior 6 into a pressure medium chamber 10 and a pressing medium chamber 12.

[0030] The material to be pressed, for example grapes, is filled into the pressing medium chamber 12 through a filling and emptying opening 14, and the pressure medium chamber 10 is pressurized with a pressure medium, for example with compressed air, which can have a pressure of, for example, 1.2 to 2 bar, after the opening 14 has been closed by a cover 15 between the inner wall of the container 2 and the membrane 6.

[0031] On the side of the container 2 opposite the closable filling and emptying opening 14 is a juice outlet 16, which can be arranged on the underside of the container 2 during the pressing process by rotating the container 2 into the corresponding position and can be opened and closed by a juice outlet valve 17. Preferably, several juice outlets 16 are arranged along the longitudinal axis 4 of the container 2, which are connected to one another by a common juice collection line 18, via which the pressed grape juice is fed to a collection container (not shown) for further processing.

[0032] As the representation of Fig. 1 and Fig. 2 can still be removed, there are several liquid-permeable, preferably flexible drainage elements 20 inside the container 2, which are arranged above the juice outlets 16 during the squeezing process.

[0033] As can be further seen from the figures, in the area above the drainage elements 20, ie in the air space above the vertically aligned drainage elements, a ventilation valve 22 is arranged, which in the same way as the juice drain valve 17 is controlled by a Fig. 2 schematically indicated electronic control device 24 is controlled in order to supply the pressing medium chamber 12 with ambient air.

[0034] According to the presentation of the Fig. 1, Fig. 3 and Fig. 4, the vent valve 22 is arranged on the lid 15 slidably mounted on the press container 2 and comprises a nozzle 25 with a continuous tube, which has a substantially smooth-walled and rectilinear inner passage area and can be closed by a closure lid 26. The closure lid 26 is pivoted about a pivot axis 32 by an actuator, in particular in the form of a double-acting compressed air cylinder 28 and an associated lever mechanism 30, in order to close or release the nozzle 25 and thereby open or close the valve 22. Due to the interaction of the actuator 28 controlled by the electronic control device 24 and the lever mechanism 30, a combined sliding and pivoting movement preferably takes place when closing the container 2, as shown in the Fig. 3 and Fig. 4 is indicated by the opened and closed closure lid 26.

Claims

[1] Press (1) for pressing liquid material, in particular grapes, with a pressure-resistant container (2), the container interior (6) of which is divided by a flexible press membrane (8) into a pressure medium chamber (10) and a pressing medium chamber (12), and with at least one drainage element (20) arranged upright in the container interior (6) during the pressing operation, to which a juice outlet (16) located in the lower region of the pressing medium chamber (12) is assigned, characterized by that a ventilation valve (22) is provided in the area above the drainage element (20), via which the pressing medium space (12) can be supplied with ambient air. [2] Press according to claim 1, characterized by that the ventilation valve (22) is positioned at the top point of the container (2) in the pressing position of the press (1) [3] Press according to claim 1 or 2, characterized bythat the ventilation valve (22) comprises a continuous tube (25) with a substantially smooth-walled and rectilinear inner passage area. [4] Press according to claim 3, characterized by that the ventilation valve (22) is formed in the form of a nozzle in the outer region of the container (2) and can be closed by a pivotable closure cover (26). [5] Press according to claim 4, characterized by that the closure cover (26) can be closed via an actuator, in particular a compressed air cylinder (28), and a lever mechanism (30). [6] Press according to claim 5, characterized by that the ventilation valve (22) opens automatically when a maximum overpressure in the interior of the container (2) is exceeded, counter to the closing force generated by the actuator (28), in order to ventilate the interior of the container (2) to avoid damage to the container (2). [7] Press according to one of claims 5 or 6, characterized bythat a pressure sensor is assigned to the interior (6) of the container (2), in particular the pressure medium chamber (10), and that the actuator (28) opens or closes the ventilation valve (22) depending on the pressure value detected by the pressure sensor. [8] Press according to one of claims 5 to 7, characterized by that the opening and closing of the ventilation valve (22) is carried out by an electronic control device (24) depending on the closing state of a juice outlet valve (17) assigned to the juice outlet (16), via which the juice outlet (16) can be closed. [9] Press according to claim 8, characterized by that the ventilation valve (22) is open when the juice drain valve (17) is closed, and that the ventilation valve (22) is closed when the juice drain valve (17) is open. [10] Press according to claim 8, characterized bythat the ventilation valve (22) is opened with a time delay by the actuator (28) to clean it of adhering material to be pressed when, after a pressing process, the pressure medium chamber (10) is subjected to negative pressure in order to move the pressing membrane (8) away from the material to be pressed in the direction of the container wall. [11] Press according to one of the preceding claims, characterized by that the ventilation valve (22) is received on a lid (15) of the container (2) closing a filling and emptying opening (14) through which the pressing medium chamber (12) can be filled with the material to be pressed. [12] Press according to one of the preceding claims, characterized by that the ventilation and venting of the entire volume not occupied by the material to be pressed in the pressing medium chamber (12) takes place exclusively via the ventilation valve (22).

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