Apparatus for processing incoherent plastic material

Abstract

An apparatus for processing incoherent plastic material is described, with a container for holding the incoherent plastic material and a moving device that moves the incoherent plastic material in the container by suctioning the plastic material via the Venturi effect, with the aim of avoiding the formation of material bridges inside the container and thus facilitating the discharge of the incoherent plastic material from the container, especially for incoherent plastic material that has an elastomeric phase and is characterized by a high coefficient of friction and poor transport or flowability.

Description

Apparatus for processing incoherent plastic material Background of the invention

[0001] The invention concerns an apparatus for processing incoherent plastic material, namely in the form of granules and / or microgranules and / or pellets and / or powder and / or flakes and / or lentils, or the like, and a use of the apparatus itself.

[0002] Specifically, but not exclusively, the invention can be usefully applied to the containment of incoherent plastics, for example in a dosing system or in a material dehumidification and / or drying system, particularly when the incoherent plastics are intended to feed a machine used in various plastic processing fields such as, for example, injection, extrusion, thermoforming, calendering, etc.

[0003] In particular, reference is made to an apparatus which comprises at least one container which is configured to contain incoherent plastic material, and which is equipped with a lower outlet through which the plastic material, which has been introduced into the container, must then be extracted with ease and regularity of flow and without any impediment, in particular by relying mainly on a movement by falling of the material, i.e. by the effect of the force of gravity.Prior art

[0004] It is known that some incoherent plastics tend to generate stagnation or packing phenomena when contained in hoppers such as, for example, holding hoppers, dehumidification and / or drying hoppers, dosing station hoppers, storage hoppers, etc.

[0005] These materials, under certain conditions, have a poor ability to move spontaneously under the force of gravity alone, even in the presence of vertical or very inclined surfaces on the hopper walls.

[0006] In practice, the desired movement of the material is not always guaranteed. Sometimes voids form within the mass of material that are not filled by the surrounding material. This material, remaining stationary, generates so-called “bridges,” or self-supporting portions of material that impede the descent of the rest of the material, with the consequent risk of discontinuous, incomplete, or uncertain descent of the material and / or uncontrolled emptying of the hopper.

[0007] Typically, these materials are thermoplastic elastomers or plastics with an elastomeric phase. An example of these materials is SEBS (Styrene-Ethylene-Butylene-Styrene), which exhibits poor flow under the action of gravity alone (slumpability) both in its virgin form and (even more so) in its recycled form (generally obtained from grinding).

[0008] A similar problem (slumpability) can arise, for example, in plastic material in the form of flakes or lentils, or in incoherent plastic material with particles of highly variable and non-uniform shapes and sizes.

[0009] The use of mechanical “bridge-breakers” is well known, but they do not always manage to move the material effectively. For example, the use of a screw conveyor to move the material is well known, but this sometimes creates hollow areas without generating a constant flow of material.

[0010] It is noted that in certain applications, such as injection molding, material demand can be discontinuous, with operational pauses due to the operation of the plasticizing screw (which typically has a loading phase for the incoherent material and a transfer phase for the molten material). Therefore, when the molten material is injected into the mold, the feed of the incoherent material is interrupted. It is therefore necessary to periodically stop the descent of the incoherent plastics from the feed hopper, resulting in difficulty restarting the descent in the next phase, as the initial friction coefficient (with stationary material) is higher than the dynamic friction coefficient (with moving material).

[0011] Another drawback of the prior art is caused by the use of mechanical “bridge breakers” with moving parts, with the consequent need for appropriate protection to ensure workplace safety.

[0012] It is also known to try to facilitate the material’s free-fall movement through the use of vibration systems. However, these systems are ineffective, especially for difficult-to-handle materials, sometimes generating the opposite effect to the desired one, namely compaction of the material.

[0013] The prior art also involves the use of deformable containers, which, however, are not capable of ensuring the desired movement of certain materials. Furthermore, as they are difficult to clean, they are not always acceptable, especially in certain sectors (e.g., medical and pharmaceutical).

[0014] Furthermore, in certain cases, to ensure proper material movement, it is known to load in small batches, to reduce the material’s dwell time in the hopper, and / or to avoid packing due to a large mass of material weighing down the base of the unloading area. This could, however, complicate the management of the production process and reduce its efficiency.Summary of the invention

[0015] One purpose of the invention is to propose a solution capable of obviating oneor more of the aforementioned limitations and drawbacks of the prior art.

[0016] One purpose is to provide an apparatus for containing incoherent plastic material and ensuring its discharge by gravity.

[0017] One purpose is to prevent the formation of material accumulations (for example, so-called bridges) or other phenomena in a mass of incoherent plastic material present in a container that could hinder the flow and continuous and / or regular discharge of the material from the container.

[0018] One advantage is to reduce the risk of the incoherent plastic material containing a hopper becoming stuck.

[0019] One advantage is to ensure a high capacity for handling incoherent plastics due to the force of gravity during unloading.

[0020] One advantage is allowing continuous, complete, and reliable descent of incoherent plastics and / or controlled emptying of the container.

[0021] One advantage is improving the handling capacity under the action of gravity, even for incoherent plastic material with a high coefficient of friction, such as plastic material with an elastomeric phase.

[0022] One advantage is creating an apparatus capable of handling the material effectively without the use of moving mechanical parts.

[0023] One advantage is providing an apparatus, usable for processing incoherent plastics, that is easy to clean and / or capable of avoiding the formation of stagnation or deposit areas of the processed material.

[0024] One advantage is enabling the desired handling of incoherent plastic material even in the case of a high mass of material.

[0025] One advantage is providing an apparatus, suitable for processing incoherent plastics, that is constructionally simple and economical.

[0026] These purposes and advantages, and others, are achieved by an apparatus and by using an apparatus according to one or more of the claims listed below.

[0027] In one example, an apparatus for processing incoherent plastic material comprises a container for holding the incoherent plastic material and a moving device arranged in the container for moving the incoherent plastic material by suctioning the plastic material via the Venturi effect.

[0028] Suction moving of the material prevents the formation of material bridges or other obstacles to the movement of the material inside the container, and thus facilitates thedischarge of incoherent plastics from the container, especially for incoherent plastics that have an elastomeric phase and / or are characterized by a high coefficient of friction and poor transport or flowability.

[0029] The suction moving device may be operated periodically, with programmed periods of operation (e.g., each operation period lasting less than 30 seconds, or less than 60 seconds, or less than 90 seconds) alternating with programmed periods of dwell (e.g., each dwell period lasting less than 120 seconds, or less than 240 seconds, or less than 300 seconds, or less than 450 seconds).

[0030] The suction moving device may, in particular, be activated by electronic control means programmable via a logic determined based on a time of stationary or immobility of the material in the hopper (i.e., the time between one material withdrawal and the next). In one example, if the material remains stationary (from one withdrawal to the next, where a withdrawal consists of a discharge of material through the lower outlet) for a time longer than a predetermined value (in particular, 50 seconds, or 150 seconds, or 250 seconds, or 450 seconds, or a value greater than 450 seconds), then the suction moving device is activated automatically. It should be noted that the time required for a material withdrawal may depend on various operating parameters, such as, for example, the morphological characteristics of the hopper, the quantity of material present inside the hopper, the hourly production required by the processing machine, etc.

[0031] The flow of incoherent plastic material, which is generated by the suction moving device (particularly with bottom-feed and upward flow), fluidifies the incoherent plastics and allows the material to be processed not only by breaking up any lumps and / or agglomerations of material, reducing the risk of material stagnation, bridges, and other obstacles to the flow of the material, but also by achieving a surface dehumidification effect on the incoherent plastic particles.

[0032] It has been observed, in particular, that the process gas (e.g., air), which is supplied under pressure to generate suction via the Venturi effect, expands during use inside the container and, as a result of this expansion, improves its dehumidification capacity, in particular by decreasing its dewpoint value. It is possible, for example, depending on the quality of the process gas used, to reach a dewpoint value of between -25°C and -45°C.

[0033] It has been observed that this dehumidification action, especially in the presence of materials with a high tendency to stick due to surface moisture, improves the descent and / or flow of the material towards the discharge area.

[0034] It has also been observed that the use of the suction moving device limits the formation of dust that accumulates inside the container and, furthermore, promotes the homogeneous movement of the incoherent plastics even if the plastics are heterogeneous, that is, even if the particles that make up the incoherent material are of different shapes and sizes (for example, reground recycled materials), avoiding the separation of the particles themselves.

[0035] The proposed solution does not require the use of moving parts and is therefore particularly safe and / or with a reduced risk of injury and / or without the need for appropriate safety protections.

[0036] The incoherent plastics may be discharged from the container in a smooth and fluid manner and may effectively feed a user machine, without compromising its functionality due to feeding errors.Brief description of the drawings

[0037] The invention may be better understood and implemented with reference to the attached drawings, which illustrate an exemplary and non-limiting embodiment thereof, in which:Figure l is a vertical elevation view, with some parts removed to better highlight others, of a first example of an apparatus for processing plastic material in accordance with the present invention;Figure 2 shows the apparatus of Figure 1 with some parts in cross-section; Figure 3 shows an enlarged detail of Figure 2;Figure 4 is a section, along a horizontal section plane with a top view, of the apparatus of Figure 1;Figure 5 is a perspective view, with some parts removed to better highlight others, of a second example of an apparatus for processing plastic material in accordance with the present invention;Figure 6 is a vertical elevation section of the apparatus of Figure 5. Detailed Description

[0038] For simplicity and clarity of explanation, similar elements from different embodiments have been indicated with the same numbering.

[0039] With reference to the figures mentioned above, 1 has been indicated as a whole an apparatus for processing incoherent plastic material, where “incoherent” means in the form of granules and / or microgranules and / or pellets and / or powder and / or flakes and / orlentils, or other similar particles. The incoherent plastics may include, in particular, a material with an elastomeric phase and / or a material characterized by a high friction coefficient and poor transport or flowability.

[0040] The apparatus 1 may be used to contain incoherent plastics within a dosing system, or a material dehumidification and / or drying system. The incoherent plastic material contained in apparatus 1 may be intended, in particular, to feed a user machine (not illustrated) in various plastic processing fields, such as injection molding, extrusion, thermoforming, calendering, etc.

[0041] The apparatus 1 comprises at least one container 2 configured to contain the incoherent plastic material. Container 2 comprises wall means that define a containment volume for the incoherent plastics.

[0042] The container 2 comprises a drain 3 to allow the incoherent plastic material to be discharged by gravity from the container 2.

[0043] The apparatus 1 comprises at least one moving device 4 with at least one lower inlet 5 located in the container 2. The moving device 4 comprises at least one upper outlet 6 located in the container 2.

[0044] The moving device 4 comprises at least one gas inlet 7 arranged to generate a Venturi effect suction that causes the incoherent plastics to flow along duct means extending from the lower inlet 5 to the upper outlet 6.

[0045] Apparatus 1 may comprise, in particular, a hopper 8 configured to contain incoherent plastics. The hopper 8 may comprise, in particular, a discharge mouth 9 configured to allow the incoherent plastics to be discharged by gravity from the hopper 8. The container 2 may be arranged, in particular, to receive the incoherent plastics that have fallen directly from the discharge mouth 9.

[0046] The hopper 8 may be arranged, in particular, above the moving device 4. The upper outlet 6 may be arranged, in particular, at a lower height than the discharge mouth 9.

[0047] The discharge mouth 9 may be arranged, in particular, at the bottom of a material containment volume defined by means of the wall of the hopper 8.

[0048] The discharge mouth 9 may be provided, in particular, with a movable closing member (in particular, movable upon command) between a closed position, in which it prevents the incoherent plastic material from being discharged through the discharge mouth 9, and at least one open position, in which it allows the incoherent plastic material to be discharged through the discharge port 9. The material outlet opening through the dischargeport 9 may, in particular, be inclined. The closing member may be operated, in particular, by an actuator, for example, an actuator controlled by electronic and programmable control means of the apparatus 1.

[0049] In this specific example, the closing member of the discharge port 9 comprises a shutter (for example, in the form of a bulkhead). The opening and closing movement of the shutter may comprise, in particular, a rotation.

[0050] The upper outlet 6 may be, in particular, arranged externally with respect to a vertical direction passing through at least one point of a passage section of the outlet opening of the discharge port 9. The upper outlet 6 may be, in particular, arranged externally with respect to all vertical directions passing through the entire passage section of the outlet opening of the discharge port 9. The upper outlet 6 may be, in particular, arranged externally with respect to vertical directions passing through the majority (more than half the area) of the passage section of the outlet opening of the discharge port 9.

[0051] The apparatus 1 may comprise, in particular, protection means 10 (see example in Figures 5 and 6) arranged in such a way as to create a screen (impermeable to incoherent plastic material) that occupies a portion of the containment volume of the incoherent plastic material in the container 2. The protection means 10 may be arranged, in particular, to interact in contact with at least a portion of the incoherent plastic material that occupies the containment volume of the container 2.

[0052] The discharge outlet 9 of the hopper 8 (not shown in Figures 5 and 6) may be arranged, in particular, above the protection means 10, for example in such a way that the material discharged from the discharge outlet 9 can fall (directly) onto the protection means 10 and then slide downwards without affecting the upper outlet 6 which remains protected by the protection means 10.

[0053] The protection means 10 may include, in particular, a screen arranged above the upper outlet 6 to protect the upper outlet 6 from incoherent plastic material entering the container 2.

[0054] The protection means 10 may include, in particular, a screen arranged between the discharge outlet 9 and the upper outlet 6.

[0055] The protection means 10 may include, in particular, a screen defining a cover arranged to cover the upper outlet 6. The cover may be, in particular, concave downwards. The cover may be, in particular, dome-shaped. The cover may be, in particular, roof-shaped with one, two, or more slopes, where each slope may be, for example, flat or convex.

[0056] The protection means 10 may comprise, in particular, wall means arranged at a steep angle to a horizontal plane (for example, an angle greater than 45°, or greater than 60°, or greater than 70°, or greater than 75°, with respect to a horizontal plane) in such a way as to facilitate the sliding of the incoherent plastic material on the wall means and, therefore, in such a way as not to represent an obstacle to the movement (fall) of the material itself entering the container (falling from the discharge outlet 9). The wall means may comprise, in particular, at least two inclined walls arranged in such a way as to form a covering consisting of a double-pitched roof, for example with a cross-section comprising at least one portion shaped like an inverted V.

[0057] The protection means 10 may be arranged, in particular, within the containment volume defined by the wall means of the container 2. The protection means 10 is distinct from the wall means of the container 2 which defines the containment volume of the incoherent plastic material in the container 2. The protection means 10 may comprise, in particular, at least one rigid and / or static body. The protection means 10 is distinct from the feeding means (for example, the hopper 8) which introduces the incoherent plastic material into the container 2.

[0058] The protection means 10 may comprise, in particular, at least one wall having at least one portion of the wall arranged at a higher level than a level of the upper outlet 6. The protection means 10 may comprise, in particular, at least one wall having at least one portion of the wall arranged at a lower level than a level of the upper outlet 6.

[0059] The protection means 10 may be, in particular, at least partially interposed between the upper outlet 6 of the moving device 4 and an area of the container 2 at which the incoherent plastic material enters the containment volume of the container 2 itself.

[0060] The protection means 10 may be, in particular, shaped and arranged in such a way as to create a screen that prevents incoherent plastic material from occupying an area located in front of the upper outlet 6 of the moving device 4. The protection means 10 may comprise, in particular, a wall (for example flat or convex) that acts as a screen and that delimits at least in part an area of the containment volume of the container 2 that is located in front of the upper outlet 6 of the moving device 4.

[0061] The protection means 10 may comprise, in particular, two or more walls configured to screen the upper outlet 6.

[0062] The protection means 10 may be arranged, in particular, at least in part below, in a vertical direction, at least part of the discharge outlet 9.

[0063] The protection means 10 serve to protect the upper outlet 6 from a possible excessive accumulation of material in front of the upper outlet 6 itself, so as to ensure effective action of the moving device 4.

[0064] The protection means 10 may, in particular, be extended transversely in length with respect to a vertical direction.

[0065] The protection means 10 may, in particular, be attached to a wall of the container 2 and / or may protrude into the interior of the container 2.

[0066] The protection means 10 may comprise, in particular, at least one wall with an upper edge 11 arranged at least partly or entirely above the upper outlet 6 of the moving device 4. In this specific example, the upper edge 11 comprises a vertex of the inverted V-shaped roof structure.

[0067] The protection means 10 may comprise, in particular, at least one wall with an upper portion arranged at a higher height than the upper outlet 6 and with a lower portion arranged at a lower height than the upper outlet 6. The protection means 10 may be, in particular, arranged at least partly or entirely at a higher height than the lower inlet 5.

[0068] The container 2 may comprise, in particular, an inclined wall 12 which delimits the containment volume of the incoherent plastic material.

[0069] The lower inlet 5 may comprise, in particular, a material inlet section that is inclined and faces horizontally the inclined wall 12 of the container 2.

[0070] The outlet 3 may be, in particular, arranged at the bottom of the container 2.

[0071] The lower inlet 5 may be, in particular, arranged above the outlet 3.

[0072] A direction of flow of the incoherent plastic material at the upper outlet 6 may be, in particular, inclined downwards, that is, it may comprise a horizontal flow component and a vertical flow component downwards (as in the example illustrated).

[0073] At least one part of the upper outlet 6 and at least one part of the inclined wall 12 may be arranged at the same height.

[0074] A flow direction of the incoherent plastic material at the upper outlet 6 may, in particular, be directed toward the aforementioned inclined wall 12 of the container (as in the illustrated example).

[0075] The upper outlet 6 may be configured, in particular, such that a flow direction of the incoherent plastic material at the upper outlet 6 has a horizontal flow component.

[0076] The upper outlet 6 may, in particular, be arranged off-center in the container 2, where “off-center” is to be understood as follows: the upper outlet 6 is arranged in such away that the flow of the incoherent plastic material at the upper outlet 6 is directed towards an area with a high risk of bridging: this means, in practice, that, considering a horizontal section of the container 2 at at least one point of the aforementioned upper outlet 6 and considering, furthermore, a horizontal line that passes through the aforementioned point and that is orthogonal to the aforementioned horizontal flow component at that point, it will be found that the portion of the area of the aforementioned horizontal section that is located in front of the aforementioned horizontal line will be greater than the portion of the area of the aforementioned horizontal section that is located behind the aforementioned horizontal line, where “in front of’ and “behind” refers to the direction defined by the aforementioned horizontal flow component at that point.

[0077] In practice, the upper outlet 6, when arranged off-center in the container 2, as in the example illustrated, will emit an outlet jet (a mixture of material and process gas) directed towards a relatively “wide” area of the containment volume, so as to affect a large internal volume of the container 2 and increase the effectiveness in breaking, or preventing the formation of, bridges.

[0078] A use of the apparatus 1 is described to break, or prevent the formation of, bridges or other obstacles of incoherent plastic material that may form in the aforementioned container and therefore to ensure the smooth flow and continuous and regular fall of the material by gravity and the desired emptying (without obstacles and without unexpected interruptions) of the container 2.

[0079] This use includes the step of introducing the incoherent plastic material into the container 2 and the step of supplying a pressurized gas to the gas inlet 7 in such a way as to determine a flow of incoherent plastic material contained in the container 2, where this flow proceeds along the duct that goes from the lower inlet 5 to the upper outlet 6.

[0080] It is noted that this use envisages that the incoherent plastic material introduced into the container 2 may have, in particular, a Shore hardness lower than 60A, where Shore hardness is measured according to the ASTM D2240 standard.

[0081] The incoherent plastic material introduced into container 2 may have, in particular, a Shore hardness lower than 52A, always measured according to the ASTM D2240 standard.

[0082] The incoherent plastic material introduced into container 2 may have, in particular, a Shore hardness greater than or equal to 32A, always measured according to the ASTM D2240 standard.

[0083] The incoherent plastic material introduced into container 2 may include, in particular, a thermoplastic elastomer. The incoherent plastic material introduced into container 2 may include, in particular, SEBS (Styrene-Ethylene-Butylene-Styrene).

[0084] The phase of supplying pressurized gas to the gas inlet 7 may be, in particular, controlled with a periodic actuation alternating pre-set actuation periods (with consequent upward movement of the material by suction from the bottom and discharge from the top) and pre-set dwell periods.

[0085] During the phase of introducing the material into the container 2, the outlet 3 may be closed to prevent the discharge of the incoherent plastic material from the container 2.

[0086] The phase of supplying gas to the gas inlet 7 may be, in particular, carried out after the phase of introducing material into container 2.

[0087] After the phase of supplying gas to the gas inlet 7, the outlet 3 may be opened to discharge incoherent plastic material from the container 2.

[0088] As mentioned, when the pressurized gas is supplied to the Venturi effect moving device, thanks to the Venturi effect, a vacuum is generated at the lower inlet 5, so that the incoherent plastic material is sucked through the lower inlet 5 and then moved (lifted) along at least one duct inside the moving device 4 towards the upper outlet 6, through which the incoherent plastic material (sucked at the base of the device) exits together with the process gas used to generate the Venturi effect.

[0089] In this specific example, the duct (for the passage of the process gas and the incoherent plastic material) of the Venturi-effect moving device 4 has a circular crosssection at the gas inlet 7, i.e. the inlet area of the process gas that generates the Venturi effect, although it is possible to foresee that the cross-section in the gas inlet area has other shapes.

[0090] The duct (for the passage of the process gas and the incoherent plastic material) of the Venturi-effect moving device 4 includes one end featuring the lower inlet 5 which, in this specific example, is provided with an inclined inlet section (specifically, in the shape of a flute beak). This inclination, on the one hand, facilitates the entry of incoherent plastic material into the duct and, on the other hand, does not represent an obstacle to the exit of the material from the container 2 through the outlet 3 located near the lower inlet 5.

[0091] The Venturi effect device may comprise, in particular, a series of radial holes arranged circumferentially around a section of the duct so as to promote the generation of a flow that will then exit from the upper outlet 6 of the duct. This flow causes a negativepressure that determines a withdrawal of the material from the lower inlet 5 and therefore the movement (ascending) of the incoherent plastic material along the duct towards the upper outlet 6.

[0092] The Venturi effect device may be controlled, in particular, so as to operate with a process gas operating pressure between 0.5 and 7 bar. The operating pressure value may be selected (and used as a set point by the control means) based on one or more of the following parameters: the specific density of the incoherent plastic material, the geometry and / or dimensions of the apparatus 1, the particle size of the incoherent material, etc.

[0093] The Venturi device may be controlled, in particular, to operate with a process gas operating flow rate between 25 and 228 dm3 / min. The process gas operating flow rate may be selected and / or calculated (and possibly used as a set point by the control means) based on the quantity of incoherent plastic material currently being processed in the container 2, for example, to achieve a desired degree of fluidification of the material itself.

[0094] The process gas supplied under pressure to the Venturi device may include, in particular, air, nitrogen, or a mixture of air and nitrogen.

[0095] The choice of process gas may be made, in particular, based on the greater or lesser sensitivity to humidity and / or oxidation of the incoherent plastic material being processed.

[0096] It is possible, in particular, to provide that the process gas is fed to the gas inlet 7 of the Venturi device at a controlled temperature, for example, between 15°C and 160°C. It is possible, in particular, to provide that the process gas is heated (to a temperature above ambient temperature, or above 50°C, or above 75°C, or above 100°C) before being fed to gas inlet 7 of the Venturi device.

[0097] The container 2 may be equipped, in particular, with thermal insulation means (e.g., a lining with insulating material) configured to limit heat loss towards the outside of container 2, for example, to prevent cooling of the material when using a preheated process gas.

[0098] The process gas supply may be controlled so that the operating values of the following three process gas parameters, namely temperature, pressure, and flow rate, have values such as to ensure a Venturi effect suction capacity capable of moving the material in the duct from the lower inlet 5 to the upper outlet 6, with an energy sufficient to ensure the breaking, or prevention of the formation, of material bridges in container 2.

[0099] The process gas supplied under pressure to the gas inlet 7 of the Venturi effectdevice may have, in particular, a predetermined degree of humidity, for example, it may have a dewpoint value between -15 °C and -80 °C.

[0100] As mentioned, the protection means 10 constitutes screening means shaped and arranged in such a way as to protect the upper outlet 6 in order to prevent the clogging of material in that area.

[0101] The protection means 10 allows the creation of an empty, or almost empty, volume located (in particular below the protection means 10) at an area adjacent to (in front of) the upper outlet 6 of the Venturi-effect moving device 4, so that the moving device 4 itself can discharge the incoherent plastic material, taken from the lower inlet 5, into an area of the container 2, in particular located above the lower inlet 5, without encountering obstacles since it is substantially empty or with little incoherent plastic material.

[0102] The protection means 10 is shaped and arranged, in particular, to ensure the generation of a protected volume whose size is adequate for the flow rate of incoherent plastic material exiting the Venturi effect device.

[0103] It should be noted that the protection means 10 is shaped and arranged, in particular, so as not to itself represents an impediment to the flow of incoherent plastic material discharged downward from the hopper 8 installed above the Venturi effect moving device 4.

[0104] In the specific example (Figures 5 and 6), the protection means 10 is sized, arranged, and oriented in an indicative and non-limiting manner.

[0105] The apparatus 1 may comprise, in particular, material sensor means 13, in particular material presence sensor means. The sensor means 13 is connected to the control means (electronic and programmable) of the apparatus 1. The control means may be configured (programmed) to ensure that the discharge area of the Venturi-effect moving device 4 (in practice, the area located in front of the upper outlet 6) is always sufficiently free of the material itself.

[0106] The sensor means 13 may comprise, in particular, a level sensor that measures the level of incoherent plastic material contained in the container 2 and which may be used by the control means to limit the level of material in the container 2, for example to control the discharge actuator that controls the discharge outlet 9 of the hopper 8, i.e., which controls the introduction of material into the lower container 2 from the upper hopper 8, so as to prevent discharge if the level of material in the lower container 2 has exceeded a certain threshold value.

[0107] The level sensor may comprise, in particular, a capacitive rod sensor. The level sensor may be used, in particular, to monitor the filling level of container 2, for example, to maintain the fill level of container 2 within a predetermined range. The quantity of material discharged from the upper hopper 8 directly into the lower container 2 must be such as to keep the area in front of the upper outlet 6 of the Venturi effect suction device free of material.

[0108] The quantity of material discharged from the upper hopper 8 into the lower container 2 may be determined based on the greater or lesser efficiency of the moving device 4, for example, based on the operating flow rate of the process gas that generates the Venturi effect.

[0109] The Venturi-effect moving device 4 may be controlled by the control means (for example, a CPU or a PLC or a stand-alone or system-integrated control board) of the apparatus 1.

[0110] The control means of the apparatus 1 may be connected, in particular, to the control means of the user machine (not shown) located downstream of the apparatus 1 and which receives and uses the incoherent plastic material coming from the apparatus 1 itself, so that an exchange of information occurs between the control means of the apparatus 1 and the control means of the user machine.

[0111] In practice, the phase of supplying pressurized gas to the gas inlet 7 may be controlled, in particular, in coordination with the control means of the user machine that uses the incoherent plastic material exiting from the container 2. By way of example, the actuation of the movement device 4 may be coordinated with the various molding phases of an injection molding machine.

[0112] An operating mode of the apparatus 1 may comprise, in particular, a series of periods of actuation of the moving device 4 interspersed with dwell periods, where the actuation periods and the dwell periods may be time intervals predetermined in the control program.

[0113] It is possible to provide that the actuation of the moving device 4 is interrupted, or its start is inhibited, when the discharge actuator of the container 2 (located at the outlet 3 of the container 2) is actuated to open the outlet 3, and while the outlet 3 itself remains open, to allow an emptying (at least partial) of the container 2, for example because the control means of the user machine have requested the supply of incoherent plastics.

[0114] The discharge actuator that allows emptying of the container 2 through the outlet3 may comprise, in particular, a linear actuator that controls a shutter (as in this specific example), or a rotary motor that controls a screw conveyor, or other discharge device.

[0115] At the end of the emptying period of container 2 (i.e., the period in which outlet 3 remains open), the control means of the apparatus 1 may be configured to automatically restart the moving device 4, for example, with a certain delay after the re-closure of outlet 3. This delay may have a pre-established fixed value, or a value calculated based on one or more operating parameters (for example, the current level of material in container 2). This delay may, however, be limited in order to restart the moving device 4 as quickly as possible and thus reduce the time the material remains in the container.

[0116] It is possible to provide for the operation of the moving device 4 to be stopped, or its start-up to be inhibited, when the outlet 9 of the upper hopper 8 is opened (and while it remains open) to fill the container 2 with the material falling from the upper hopper 8. The control means of the apparatus 1 is configured to interrupt or inhibit the start of the actuation of the moving device 4 during each period of time in which incoherent plastic material is introduced from the upper hopper 8 by falling material (loading, i.e., introduction of the material into the container 2).

[0117] It is possible to provide that the moving device 4 may also be activated during the aforementioned loading phase.

[0118] This may occur, in particular, when protection means is present (which may be positioned above and / or below the upper outlet 6 and) that may shield the upper outlet 6 and / or divert the incoherent plastic material, with the effect of leaving a free space in front of the upper outlet 6 and thus ensuring easy handling of the material exiting the transport duct of the Venturi-effect moving device 4.

[0119] It is possible to provide for the actuation of the moving device 4 during the aforementioned loading phase of the container 2 even in the absence of a protection device, for example by using the sensor means 13 which allows the control means to control the apparatus 1 in such a way as to leave a certain free space in the container so that the moving of the material performed by the Venturi effect device is unobstructed and effective.

[0120] It has been seen that the Venturi effect moving device 4, being arranged inside the container 2, represents an effective means for promoting the landslide of the incoherent plastic material, i.e., the spontaneous sliding downwards under the effect of its own weight. This device prevents the formation of material bridges and facilitates the flow of the material inside the container, ensuring regular, continuous, controlled, and repeatable emptying ofcontainer 2.

[0121] It has also been seen that the protection means 10 (in particular arranged to shield an internal area of container 2 located in front of the upper outlet 6 of the moving device 4) ensure the efficient operation of the moving device 4 that moves the material.

[0122] It has also been seen that the arrangement of the material sensor means 13, connected to the control means of the apparatus 1, allows a desired filling mode of the container 2 with the incoherent plastic material, ensuring the desired functionality of the Venturi effect moving device arranged to facilitate the material’s ability to slide.

[0123] Legend:1 apparatus for processing incoherent plastic material2 container3 outlet (of container 2)4 moving device5 lower inlet (of moving device 4)6 upper outlet (of moving device 4)7 gas inlet (of moving device 4)8 hopper9 discharge outlet (of hopper 8)10 protection means11 upper edge (of protection means 10)12 inclined wall (of container 2)13 sensor means

Claims

CLAIMS1. Apparatus for processing incoherent plastic material, comprising:a container (2) configured to contain incoherent plastic material and comprising an outlet (3) to allow for gravity discharge of incoherent plastic material from said container (2); anda moving device (4) with a lower inlet (5) arranged in said container (2), an upper outlet (6) arranged in said container (2), and a gas inlet (7) arranged to generate a Venturi effect suction such as to determine a flow of incoherent plastic material from said lower inlet (5) to said upper outlet (6).

2. Apparatus according to claim 1, comprising a hopper (8) configured to contain incoherent plastic material and comprising a discharge outlet (9) to allow a discharge of incoherent plastic material from said hopper (8), said container (2) being arranged to receive incoherent plastic material discharged from said discharge outlet (9).

3. Apparatus according to claim 2, wherein said hopper (8) is arranged above said moving device (4).

4. Apparatus according to claim 2 or 3, wherein said upper outlet (6) is arranged at a lower height than said discharge outlet (9).

5. Apparatus according to any one of claims 2 to 4, wherein said discharge outlet (9) is arranged at the bottom of a material containment volume of said hopper (8).

6. Apparatus according to any one of claims 2 to 5, wherein said discharge outlet (9) is provided with a closing member movable between a closed position, in which it prevents a discharge of the incoherent plastic material through said discharge outlet (9), and at least one open position, in which it allows a discharge of the incoherent plastic material through said discharge outlet (9).

7. Apparatus according to any one of claims 2 to 6, wherein said upper outlet (6) is arranged externally with respect to a vertical direction passing through at least one point of the passage section of said discharge outlet (9), or with respect to the vertical directions passing through the entire passage section, or through the majority of the passage section, of said discharge outlet (9).

8. Apparatus according to any one of the preceding claims, comprising protection means (10) configured to protect said upper outlet (6) from incoherent plastic material introduced into said container (2).

9. Apparatus according to claim 8 and according to any one of claims 2 to 7, whereinsaid protection means (10) is arranged at least partly at a lower level than said discharge outlet (9).

10. Apparatus according to claim 8 or 9, wherein said protection means (10) defines at least one screen that protects at least superiorly an area located in front of said upper outlet (6).

11. Apparatus according to any one of claims 8 to 10, wherein said protection means (10) defines at least one screen that protects at least laterally an area located in front of said upper outlet (6).

12. Apparatus according to any one of claims 8 to 11, wherein said protection means (10) is arranged in said container (2) below an inlet of the incoherent plastic material in said container (2).

13. Apparatus according to any one of claims 8 to 12, wherein said protection means (10) comprises at least one screen arranged at least partly above said upper outlet (6).

14. Apparatus according to any one of claims 8 to 13, wherein said protection means (10) comprises at least one upper edge (11) arranged at least partly at a height higher than a height of said upper outlet (6).

15. Apparatus according to any one of claims 8 to 14, wherein said protection means (10) is arranged at least partly at a height higher than said upper outlet (6).

16. Apparatus according to any one of claims 8 to 15, wherein said protection means (10) comprises an upper portion arranged at a height higher than said upper outlet (6) and a lower portion arranged at a height lower than said upper outlet (6).

17. Apparatus according to any one of claims 8 to 16, wherein said protection means is arranged at least partly at a height higher than said lower inlet (5).

18. Apparatus according to any one of claims 8 to 17, wherein said protection means (10) comprises at least one rigid body.

19. Apparatus according to any one of claims 8 to 18, wherein said protection means (10) comprises at least one downwardly concave cover.

20. Apparatus according to claim 19, wherein said at least one concave cover comprises wall means with at least one inclination greater than 45° with respect to a horizontal plane.

21. Apparatus according to any one of the preceding claims, wherein said lower inlet (5) comprises an inclined material inlet section.

22. Apparatus according to any one of the preceding claims, wherein said lower inlet (5)comprises a material inlet section facing in a horizontal direction to an inclined wall (12) of said container (2).

23. Apparatus according to any one of the preceding claims, wherein said outlet (3) is arranged at the bottom of said container (2).

24. Apparatus according to any one of the preceding claims, wherein said lower inlet (5) is arranged above said outlet (3).

25. Apparatus according to any one of the preceding claims, wherein a direction of the incoherent plastic material outlet flow at said upper outlet (6) is inclined with a horizontal flow component and with a downwardly vertical flow component.

26. Apparatus according to any one of the preceding claims, wherein said container (2) comprises an inclined wall (12) that delimits a containment volume of the incoherent plastic material.

27. Apparatus according to any one of the preceding claims, wherein at least one part of said upper outlet (6) and at least one part of said inclined wall (12) are arranged at the same height.

28. Apparatus according to any one of the preceding claims, wherein a direction of the incoherent plastic material outlet flow at said upper outlet (6) is directed towards said inclined wall (12).

29. Apparatus according to any one of the preceding claims, wherein said upper outlet (6) is configured such that a direction of the flow of incoherent plastic material exiting said upper outlet (6) has a horizontal flow component.

30. Apparatus according to claim 29 wherein said upper outlet (6) is off-center in said container (2) such that the flow of incoherent plastic material exiting said upper outlet (6) is directed toward a bridging risk area, i.e. such that, considering a horizontal section of said container (2) at least one point of said upper outlet (6) and considering a horizontal line passing through said point and orthogonal to said horizontal flow component at said point, the area portion of said horizontal section located in front of said horizontal line is greater than the area portion of said horizontal section located behind said horizontal line, where “in front” and “behind” refers to said horizontal flow component at said point.

31. Apparatus according to any one of the preceding claims, comprising sensor means (13) arranged to detect incoherent plastic material in said container (2), in particular a level of material.

32. Apparatus according to claim 31, wherein said sensor means (13) is connected to control means configured to control said apparatus (1) so that a level of incoherent plastic material in said container (2) remains lower than a level of said upper outlet (6).

33. Apparatus according to any one of the preceding claims, comprising thermal insulation means configured to limit heat loss towards the outside of said container (2).

34. Apparatus according to any one of the preceding claims, wherein said moving device (4) is arranged in said container (2).

35. Apparatus according to any one of the preceding claims, wherein said Venturi effect suction is such as to determine a flow of the incoherent plastic material along duct means which is arranged in said container (2) and which go from said lower inlet (5) to said upper outlet (6).

36. Use of an apparatus according to any one of the preceding claims for promoting the discharge of incoherent plastic material from said container (2), said use comprising the step of introducing incoherent plastic material into said container (2) and the step of supplying a pressurized gas to said gas inlet (7) to cause a flow of incoherent plastic material contained in said container (2) from said lower inlet (5) to said upper outlet (6).

37. Use according to claim 36, wherein said incoherent plastic material has a Shore hardness of less than 60 A, where the Shore hardness is measured in accordance with ASTM D2240; said incoherent plastic material having, in particular, a Shore hardness of less than 52A, where the Shore hardness is measured in accordance with ASTM D2240.

38. Use according to claim 36 or 37, wherein said incoherent plastic material has a Shore hardness greater than or equal to 32A, where the Shore hardness is measured in accordance with ASTM D2240.

39. Use according to any one of claims 36 to 38, wherein said incoherent plastic material comprises a thermoplastic elastomer.

40. Use according to any one of claims 36 to 39, wherein said step of supplying a pressurized gas is controlled with a periodic actuation alternating pre-set periods of actuation and pre-set periods of dwell.

41. Use according to any one of claims 36 to 40, wherein said step of supplying a pressurized gas is controlled in coordination with a control of a user machine arrangeddownstream of said apparatus which uses incoherent plastic material exiting from said container (2).

42. Use according to any one of claims 36 to 41, wherein said step of introducing incoherent plastic material into said container (2) is controlled so that a level of incoherent plastic material in said container (2) is such as not to obstruct said upper outlet (6).

43. Use according to any one of claims 36 to 42, wherein, during said step of introducing material, said outlet (3) is closed to prevent a discharge of incoherent plastic material from said container (2).

44. Use according to any one of claims 36 to 43, wherein said step of supplying pressurized gas is performed after said step of introducing material.

45. Use according to any one of claims 36 to 44, wherein, after said supplying step, said outlet (3) is opened to discharge incoherent plastic material from said container.

46. Use according to any one of claims 36 to 45, wherein said pressurized gas, which is supplied to said gas inlet (7), has a dewpoint value lower than -15 °C and / or higher than -80 °C.

47. Use according to any one of claims 36 to 46, wherein said pressurized gas is heated before being supplied to said gas inlet (7).

48. Use according to any one of claims 36 to 47, wherein said pressurized gas, which is supplied to said gas inlet (7), has a temperature value higher than ambient temperature, or higher than 50 °C, or higher than 75 °C, or higher than 100 °C.

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