Apparatus and method for manufacturing an object from a plastic material in a continuous cycle

Abstract

An apparatus (1) for manufacturing objects in a continuous cycle from a plastic material, comprising a dispensing unit (2), a forming station (4) for forming a plurality of objects by compression molding, a metering unit (3) having an outlet valve system that is switchable between an open configuration and a closed configuration, a plurality of partition elements upstream of the outlet valve system, the plurality of partition elements being movable between an upper limit position (X1) and a lower limit position (X2) to change the internal volume of the dispensing unit (2), and a group of actuators for moving the plurality of partition elements between the upper limit position (X1) and the lower limit position (X2), the metering unit (3) being provided with an outlet valve system (302) in a closed configuration in the filling configuration of the metering unit (3) and an outlet valve system (302) in an open configuration in the filling configuration, the apparatus (1) comprising a control unit (5) for switching the metering unit (3) from a filling configuration to a discharging configuration and from a discharging configuration to a filling configuration and driving a group of actuators to move the corresponding partition elements.

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for manufacturing objects from a plastic material in a continuous cycle.

[0002] This disclosure relates to the field of shaping objects from thermoplastic materials. More specifically, the field is that of simultaneously shaping a plurality of objects from a plastic material. In an exemplary embodiment, the object is a parison intended to form a container by subsequent blow molding.

Background Art

[0003] In the prior art for this purpose, an apparatus is known in which a metering unit is configured to form a plurality of measured plastic dosages from a flow of molten plastic. An example of this type of apparatus is described in JP2017177455A, where a rotating element rotates integrally to divide the flow of molten plastic into a plurality of identical dosages. However, this type of apparatus does not allow for accurately forming the dosages nor adjusting the amount of plastic in one dosage independently of the amounts in other dosages. In this regard, for example, as described in JPH06114867A, an apparatus equipped with a system for measuring and adjusting the amount of material is known in the prior art to adjust the amount of plastic in each dosage. This document describes a plastic dispenser with a plurality of outlet ports, and each outlet port is provided with a metering and injection unit configured to measure and adjust the amount of material forming the dosage. However, this document does not describe in sufficient detail the method of measuring and adjusting the material to form the dosage.

[0004] Patent document US5858420 describes a solution related to an injection molding system in which a continuous flow of plastic is divided and distributed, and the injected plastic is measured by a volume measurement system.

Summary of the Invention

[0005] The present disclosure aims to provide an apparatus and a method for manufacturing an object from a thermoplastic material in a continuous cycle in order to overcome the above-mentioned drawbacks of the prior art.

[0006] More specifically, an object of the present invention is to provide an apparatus and a method for manufacturing an object from a plastic material in a continuous cycle, the apparatus and method being capable of uniformly dividing the material from a continuous flow of plastic into a plurality of doses.

[0007] Another object of the present invention is to propose an apparatus and a method for manufacturing an object from a plastic material in a continuous cycle so as to enable the amount of a certain dose of plastic to be adjusted independently of other doses.

[0008] Yet another object of the present disclosure is to provide an apparatus and a method for manufacturing an object from a plastic material in a continuous cycle, the apparatus and method being capable of obtaining a plurality of doses, the volume of which is accurately known.

[0009] These objects are fully achieved by the apparatus and method of the present disclosure for manufacturing an object from a plastic material in a continuous cycle, which are characterized in the appended claims.

[0010] The present disclosure relates to an apparatus for manufacturing an object from a plastic material in a continuous cycle. The plastic material can be, for example, HDPE, PET or PP. The HDPE plastic material can have a melt index (or melt flow index) of 0.2 to 3 g / 10 min (at 190 °C, 2.16 Kg, ASTM D1238). The HDPE plastic material has a density of 0.940 to 0.970 g / cm 3It may have a density. The HDPE plastic material may have a unimodal or bimodal molecular weight distribution. The HDPE plastic material may contain a nucleating agent (for example, a macromolecule that is more linear compared to the chromium catalyst process and has no branching by Ziegler-Natta catalyst or metallocene catalyst). The HDPE plastic material may contain an additive that increases the barrier properties against oxygen and / or moisture by 20% to 50%. The PET plastic material may have an intrinsic viscosity of 0.72 to 1.10 dl / g (ASTM D4603-03). The PP plastic material may have a melt index between 0.5 and 4 g / 10 min (at 230 °C, 2.16 Kg, ISO 1133). The PP plastic material may have a flexural modulus between 850 and 2000 MPa. The PP material may be a homopolymer or a random copolymer or a block copolymer.

[0011] The apparatus comprises a dispensing unit. The dispensing unit is configured to dispense plastic to the apparatus or to a part of the apparatus. The dispensing unit comprises a supply duct having an inlet. The inlet may be configured to receive a continuous flow of molten plastic, for example, from an extrusion unit. The extrusion unit may be configured to receive plastic in an unprocessed form and deliver a flow of molten plastic. The outlet of the extrusion unit may be located in the supply duct of the metering unit. For example, the flow of molten plastic received by the supply duct (i.e., by the inlet of the supply duct) may be pressurized. In one example, the dispensing unit includes a plurality of delivery branches. Each delivery branch of the plurality of delivery branches, more precisely, is in fluid communication with the supply duct, for example, via a dispensing zone. The dispensing zone is preferably configured to communicate the inlet, i.e., the supply duct, with each delivery branch such that plastic is fed and distributed towards the delivery branches, i.e., is split between the delivery branches. In other words, the dispensing zone is configured to split the flow of plastic into a plurality of (separate) flows of plastic.

[0012] Each delivery branch of the plurality of delivery branches preferably has an outlet and thus defines a corresponding plurality of outlets. The distribution unit defines an internal volume between the inlet and the outlet, i.e., between the supply duct and the plurality of delivery branches.

[0013] The distribution zone may be a single distribution zone or may include a plurality of distribution zones. In one example, the plurality of distribution zones includes a first distribution zone and a second distribution zone. The first distribution zone, which is located downstream of the supply duct in the supply direction of the plastic from the inlet to the outlet, may be configured to divide the plastic flow into a plurality of (separate) plastic flows, and the second distribution zone, which is located downstream of the first distribution zone, may be configured to receive the plurality of separate plastic flows and further divide them.

[0014] In this example, the first and second distribution zones constitute the first and second branches for the inflow of the continuous plastic flow towards the supply duct.

[0015] The apparatus comprises a forming station. The forming station can be an injection molding station, or an injection compression molding station, or more preferably a compression molding station. The forming station is configured to form a plurality of plastic objects from a plurality of predetermined amounts of plastic, i.e., dosages of plastic. The forming station includes a plurality of female mold elements, i.e., a plurality of lower molds, and a plurality of male mold elements, i.e., a plurality of upper molds. Preferably, the plurality of female mold elements can be arranged in the plurality of delivery branches of the distribution unit, i.e., each female mold element can be arranged in an individual delivery branch. Thus, each female mold element is configured to receive plastic from the outlet of the individual delivery branch. Preferably, the plurality of female mold elements define a corresponding plurality of sheets, and each sheet is configured to receive a predetermined amount of plastic, i.e., a dosage.

[0016] Preferably, each of the plurality of sheets has an acceptance diameter, and the diameter of one dose of the plurality of doses is smaller than the acceptance diameter of each of the plurality of sheets.

[0017] Preferably, the acceptance diameter of the sheet is proportional to the shape of the plastic object and / or depends on the polymer properties of the plastic material (HDPE, PP or PET). In one example, the difference between the acceptance diameter of the sheet and the diameter of the dose is between 1 mm and 10 mm. Preferably, each of the plurality of sheets has an acceptance height, and the height of one dose is less than or equal to the acceptance height of the individual sheet. The plurality of male elements are configured to cooperate with the corresponding respective female elements of the plurality of female elements to define a corresponding plurality of forming cavities. The plurality of male elements are preferably configured to cooperate with the corresponding respective female elements of the plurality of female elements to form a plurality of objects from the plastic material by compression molding. In one example, the object is a parison intended to form a container by blow molding.

[0018] When the object is a parison and the plastic material is HDPE, the parison can have an axial stretchability between 1 and 1.5, preferably between 1 and 1.3. The axial stretchability is equal to the ratio between the height of the container and the height of the parison. The parison can have a radial stretchability between 1.2 and 5, preferably between 1.2 and 3. The radial stretchability is equal to the ratio between the diameter of the container and the diameter of the parison. The parison can stretch between 0.2 m / s and 2.5 m / s, preferably between 0.5 m / s and 1.5 m / s.

[0019] When the object is a parison and the plastic material is PP or PET, the parison can have an axial stretchability between 1 and 4, preferably between 1 and 3. The axial stretchability is equal to the ratio between the height of the container and the height of the parison. The parison can have a radial stretchability between 1 and 5, preferably between 1.2 and 4. The radial stretchability is equal to the ratio between the diameter of the container and the diameter of the parison. The parison can stretch between 0.2 m / s and 2.5 m / s, preferably between 0.5 m / s and 1.5 m / s.

[0020] The device can form part of a production line for containers (for example, for liquids or others) in a continuous cycle. The production line for containers may further comprise a station for blow molding a parison to form the container. In one example, the device comprises a forming station made according to that described in the patent document IT102021000032507 in the name of the applicant, which document is incorporated herein by reference. The device may also comprise a blow molding station according to that described in the patent document IT102021000032507 incorporated herein by reference.

[0021] The device comprises a metering unit. The metering unit is configured to measure a predetermined amount of plastic, that is, to form a dosage of a predetermined amount of plastic from a continuous flow. Preferably, the metering unit is configured to form a plurality of dosages of plastic simultaneously.

[0022] In one example, the metering unit includes an outlet valve system. The outlet valve system is configured to block, that is, separate, the plastic, for example, between an upstream zone and a downstream zone of the outlet valve system, with respect to the supply direction of the plastic from the inlet to the outlet. Preferably, the outlet valve system comprises a plurality of outlet valves. Each of the plurality of outlet valves can be arranged in an individual delivery branch. The outlet valve system can be switched between an open configuration and a closed configuration. For this purpose, the outlet valve system may comprise a plurality of valves, shutters or blockers. For example, in the closed configuration of the outlet valve system, the outlet valve system is configured to block the flow of plastic sent out, for example, from a distribution unit. For example, in the open configuration of the outlet valve system, the outlet valve system is configured to enable the discharge of plastic from the internal volume of the distribution unit. In this way, when shifting from the open configuration to the closed configuration of the outlet valve, the metering unit is configured to form a plurality of dosages sent from the corresponding plurality of delivery branches of the distribution unit.

[0023] Preferably, the metering unit comprises a plurality of partition elements or separating walls. The plurality of partition elements may be movable, for example, between an upper position and a lower position in order to change the internal volume of the dispensing unit, i.e., to change the amount of plastic that can be accommodated within the dispensing unit.

[0024] Preferably, the metering unit includes one operating configuration or a plurality of operating configurations, i.e., is operable in one operating configuration or a plurality of operating configurations. For example, the metering unit comprises a filling configuration in which the outlet valve system is in a closed configuration. For example, the metering unit comprises a discharging configuration in which the outlet valve system is in an open configuration.

[0025] The apparatus may comprise a control unit configured to switch the metering unit from a filling configuration to a discharging configuration and vice versa.

[0026] In one embodiment, the metering unit comprises an additional valve system. The additional valve system is preferably configured to separate, i.e., block, the flow of plastic from an upstream zone of the additional valve system to a downstream zone of the additional valve system. The additional valve system may be switched between an open configuration and a closed configuration. For this purpose, the additional valve system may comprise a plurality of valves, shutters or blockers. For example, when the metering unit is in the filling configuration, the additional valve system is in the open configuration. When the metering unit is in the discharging configuration, the additional valve system is in the closed configuration. Preferably, the additional valve system is arranged upstream of the outlet valve system. In this way, the outlet valve system is configured to separate, i.e., block, plastic between a downstream zone of the additional valve system and a downstream zone of the outlet valve system.

[0027] The internal volume includes an operating portion located between the outlet valve system and the additional valve system. In other words, the portion of the internal volume between the outlet valve system and the additional valve system constitutes the operating portion of the internal volume. For example, the outlet valve system can be set to a closed configuration and the additional valve system can be set to an open configuration to allow plastic to accumulate in the operating portion of the internal volume. The outlet valve system can be set to an open configuration and the additional valve system can be set to a closed configuration to allow plastic to be discharged from the operating portion of the internal volume.

[0028] In an example including an outlet valve system and an additional valve system, a plurality of partition elements are preferably arranged between the additional valve system and the outlet valve system. Preferably, each of the plurality of partition elements is movable between an upper limit position and a lower limit position to change the operating portion of the internal volume of the dispensing unit. The operating portion of the internal volume can be variable from a contracted configuration having a minimum volume to an expanded configuration having a maximum volume. More specifically, the difference between the maximum volume and the minimum volume of the operating portion is equal to the volume of one dose multiplied by the number of delivery branches.

[0029] In this regard, the metering unit may include a filling configuration, in which the metering unit is configured to allow, for example, plastic to accumulate in the operating portion of the internal volume of the dispensing unit. Preferably, in the filling configuration, the outlet valve system is in a closed configuration and the additional valve system is in an open configuration. In this way, plastic can be supplied to the operating portion of the internal volume. The metering unit may include a discharging configuration, in which the metering unit is configured to allow, for example, plastic to be discharged from the operating portion of the internal volume. In the discharging configuration, the metering unit may be configured to allow a dose of plastic formed from the plastic flow to be discharged through the outlet. Thus, in the discharging configuration, the device is configured to supply a dose to a plurality of sheets of a plurality of female elements. Preferably, in the discharging configuration, the outlet valve system is in an open configuration and the additional valve system is in a closed configuration to allow plastic to be discharged from the operating portion and the dose to be delivered.

[0030] The control unit is preferably configured to switch the metering unit from the discharging configuration to the filling configuration with the plurality of partition elements arranged at the upper limit position. The control unit is preferably configured to switch the metering unit from the filling configuration to the discharging configuration with the plurality of partition elements arranged at the lower limit position.

[0031] In other words, the additional valve system is configured to separate a predetermined amount of plastic from the continuous flow of plastic and to allow the predetermined amount of plastic to advance to the zone between the additional valve system and the outlet valve system, i.e., the working part. In this way, the working part is configured to be filled with a predetermined amount of plastic to expand its volume, while the plurality of partition elements are configured to move from the lower limit position to the upper limit position. The upper limit position of the partition element is preferably a fixed position, i.e., a position beyond which the partition element cannot move, which means that the internal volume (or the working part of the internal volume) cannot be further expanded during the molding operation.

[0032] In one example, the additional valve system comprises a main valve arranged in the supply duct. In one example, the additional valve system comprises a plurality of valves, and each valve of the plurality of valves is arranged in a corresponding delivery branch of the plurality of delivery branches.

[0033] In an example with an outlet valve system and an additional valve system, it should be noted that when a plurality of partition elements of the additional valve system are in the upper limit position, the outlet valve system is configured to separate an additional amount of plastic from a predetermined amount included in the operating part. For this purpose, the outlet valve system switches to an open configuration and is configured to allow the operating part to contract its volume and empty the predetermined amount of plastic contained therein, while the plurality of partition elements are configured to move from the upper limit position to the lower limit position. Thus, the additional predetermined amount of plastic separated by the outlet valve system is equal to the difference between the volume of the operating part when the plurality of partition elements are in the upper limit position and the volume of the operating part when the partition elements are in the lower limit position. More specifically, the additional predetermined amount of plastic defines the volume of a dose of plastic. Thus, the volume of each dose is known precisely.

[0034] In one embodiment, each partitioning element of the plurality of partitioning elements is disposed in a delivery branch upstream of the corresponding outlet valve. For example, in order to vary the internal volume of the dispensing unit, the plurality of partitioning elements are movable from an upper position to a lower position. In embodiments including an additional valve system and the plurality of partitioning elements, when the metering unit is in a filling configuration, the outlet valve system is in a closed configuration to block the flow of plastic from the dispensing unit, and for example, when the metering unit is in a discharging configuration, the outlet valve system is in an open configuration to enable plastic to be discharged from the internal volume of the dispensing unit. In this regard, when the metering unit is in the discharging configuration, moving the plurality of partitioning elements from an upper limit position to a lower limit position, and when the metering unit is in the filling configuration, moving the plurality of partitioning elements from the lower limit position to the upper limit position, generates a plurality of doses of plastic to be supplied to the plurality of sheets. During the movement from the lower limit position to the upper limit position, with the outlet valve system in the closed configuration, plastic advances from the inlet and accumulates within the internal volume. During the movement from the upper limit position to the lower limit position, with the outlet valve system in the open configuration, plastic exits from the internal volume. In an example comprising an outlet valve system and the plurality of partitioning elements, the amount of plastic for one dose, i.e., the amount of plastic for one dose forming the individual sheets of the plurality of sheets, is defined by the amount of plastic contained downstream of the corresponding outlet valve with the outlet valve in the closed configuration and the corresponding partitioning element in the lower limit position.

[0035] Compared to embodiments comprising an outlet valve system and an additional valve system, an apparatus comprising an outlet valve system has the advantage of being less complex while maintaining the advantage of accuracy.

[0036] It should be noted that the outlet valve system and the plurality of partitioning elements constitute separate elements of the apparatus, and they also have two separate functions. That is, the outlet valve system has the function of dividing a continuous flow (or, if there is also an additional valve system, it has the function of further dividing the amount of plastic contained in the operative part), while the plurality of partitioning elements have the function of supplying doses from the internal volume (or, if there is an additional valve system, from the operative part of the internal volume) towards the outlet.

[0037] If there is an additional valve system, this is also a separate element and has a function different from that of the plurality of partition elements. More specifically, the additional valve system has the function of dividing a continuous flow into doses.

[0038] In one example, the metering unit comprises, in addition to or preferably instead of the plurality of partition elements, the outlet valve system and the additional valve system, a plurality of cutting devices, each cutting device being arranged at the outlet and being switchable between an open configuration enabling the plastic to be fed out of the outlet and a closed configuration in which the cutting device closes the outlet and separates the amount of plastic forming the corresponding dose. Thus, in one example, the plurality of cutting devices provide an alternative solution to the plurality of partition elements and valves, in which solution the plastic is extruded from the delivery branch and the cutting devices are configured to divide the extruded plastic into parts. The device may comprise a sensor system including a plurality of sensors, each sensor of the plurality of sensors being configured to detect in real time a flow parameter correlated with the flow rate of the plastic in each delivery branch, and the control unit may be connected to the sensor system and the plurality of cutting devices and drive them according to the flow parameter. Preferably, the flow parameter represents the length of the section of plastic extruded through each outlet and arranged outside the distribution unit.

[0039] In one example, each cutting device includes a first knife and a second knife. The first knife and the second knife each include a first blade and a second blade disposed on both sides of the knife with respect to the moving direction of the knife. The first knife and the second knife are juxtaposed with each other along the moving direction. The first and second knives may be movable relative to each other to exchange positions between a further open position and the further open position via an open position and a closed position when moving from the open position to the further open position. More specifically, in the closed position of the first and second knives, the first and second knives are configured to act in conjunction to cut the dose at the outlet. In this way, each time the position is changed, the first and second knives can quickly separate the dose without obstructing the outlet.

[0040] In one example, at least one of the plurality of partition elements may be movable between a lower limit position and an upper limit position by the pressure applied to the at least one partition element by the plastic.

[0041] Alternatively, or additionally, the metering unit may comprise an actuator for at least one of the plurality of partition elements, or one actuator for each section element of the plurality of partition elements. In one example, the metering unit may include a group of actuators, and each actuator of the group of actuators is connected to a corresponding partition element of the plurality of partition elements. The actuator may be configured to move the corresponding partition element between an upper limit position and a lower limit position, preferably continuously. The actuator has the advantage that the upper and lower limit positions of the partition element can be accurately controlled, especially during the shaping operation.

[0042] In one example, the control unit may be configured to drive one or more of a group of actuators to move a corresponding partition element from an upper limit position to a lower limit position, preferably when the metering unit is in a discharge configuration. The control unit may be configured to drive one or more of a group of actuators to move a corresponding partition element from a lower limit position to an upper limit position, preferably when the metering unit is in a filling configuration. In this way, it is possible to form a plurality of doses of plastic that can be supplied to a plurality of sheets.

[0043] In one example, the plurality of partition elements includes a group of partition elements including a plurality of secondary partition elements. Preferably, each partition element of the plurality of secondary partition elements is arranged in a corresponding delivery branch of the plurality of delivery branches. The secondary partition element arranged in the delivery branch has the advantage that the amount of plastic delivered from the outlet of the delivery branch can be adjusted.

[0044] In one example, the plurality of partition elements includes a main partition element. Preferably, the main partition element is arranged in the supply duct of the distribution unit.

[0045] The main partition element arranged in the supply duct has the advantage that it can adjust the flow of plastic and supply the total amount of plastic consisting of the sum of all doses. This total amount of plastic is then divided among the plurality of delivery branches by the distribution zone to form a plurality of doses.

[0046] Preferably, the upper limit position or the lower limit position of at least one of the plurality of partition elements is adjustable to change, for example, the maximum amount of plastic that can be accommodated in the internal volume or the operating part of the internal volume. In this way, it is possible to adjust the maximum amount of plastic that can be accommodated in the internal volume (more precisely, each of the plurality of branches) or the operating part of the internal volume, for example, when the plurality of delivery branches are geometrically different from each other.

[0047] In one example, the outlet valve system comprises a plurality of pushers. For example, each pusher may be disposed in a corresponding delivery branch. Each pusher may be movable back and forth between a retracted position and a plurality of advanced positions. For example, the retracted position is a position that does not interfere with the flow of plastic in the corresponding delivery branch. For example, the advanced position is a position where the pusher closes the corresponding delivery branch. Preferably, at the plurality of advanced positions, the pusher is configured to extrude the corresponding dose through the outlet, for example, by moving in the extraction direction between the advanced positions. Preferably, in the retracted position, the pusher keeps the corresponding outlet valve of the outlet valve system open. Preferably, at the plurality of advanced positions, the pusher keeps the corresponding outlet valve of the outlet valve system closed. In this way, while the pusher keeps the corresponding outlet valve closed, the corresponding valve of the additional valve system is in an open configuration to allow the plastic to advance into the working volume portion of the dispensing unit. When moving in the extraction direction between the advanced positions, the pusher has the advantage of further separating the plastic from the working part and extruding the dose from the outlet.

[0048] In one example, the control unit is preferably programmed to control the upper or lower position of at least one partition element among a plurality of partition elements for one of a series of molding operations. Preferably, the control unit is programmed to control the upper or lower position based on (i.e., in accordance with) a check parameter. Alternatively, the control unit may be configured to drive one or more actuators in accordance with a check parameter. The check parameter may represent the one molding operation, the previous molding operation, or the previous plurality of molding operations among a series of molding operations. The check parameter may be processed at the end of a cycle for molding a plastic object, for example, outside the device for manufacturing the object, or at the end of or during the molding operation. In one embodiment, the check parameter represents the difference between the volume or mass of a single dose delivered from a delivery branch and a reference value of the volume or mass of the dose. The check parameter may be obtained from an optical sensor, a flow sensor, or a weight sensor. The optical sensor may be disposed between a plurality of female elements and the outlet of the delivery branch to measure the amount of plastic delivered from the outlet of the delivery branch, for example, by measuring the length of the delivered dose. The flow sensor may be disposed at the delivery branch or the inlet to measure the flow rate of the plastic delivered from the outlet or fed through a supply duct. In this way, the device is preferably configured to adjust a predetermined amount of plastic, i.e., the amount of plastic forming the dose through the check parameter, preferably by feedback. The weight sensor may be disposed on one of a plurality of sheets to measure the weight of a single dose within the sheet.

[0049] In one example, each female element of the plurality of female elements is movable along a longitudinal movement axis between a spaced-apart position where it does not interfere with the corresponding male element of the plurality of male elements and a proximate position where it acts in conjunction with the corresponding male element to close the formed cavity in order to compress the dosage. Each male element can be connected to an elastic element so that, for example, in response to compression of the dosage in the closed position of the formed cavity, it can perform a settling movement along the longitudinal movement axis. Preferably, the control unit can be programmed to derive a check parameter in response to the settling movement. For this purpose, the male element can perform a settling movement, for example, in proportion to the volume of the dosage contained within the formed cavity. The apparatus may comprise a distance sensor programmed to measure the distance of the settling movement. It is possible to connect the control unit to the distance sensor to receive the distance of the settling movement from the distance sensor. The control unit can be programmed to process the check parameter based on the distance received from the distance sensor and derive a control parameter. The control unit can be connected to at least one partition element of the plurality of partition elements, or to the actuator of at least one partition element, in order to control the upper limit position of at least one partition element among the plurality of partition elements via the control parameter. In this way, it becomes possible to adjust the amount of plastic within the working part of the internal volume, and thus also to adjust the volume of the dosage.

[0050] In one example, the apparatus comprises a flow sensor. The flow sensor is preferably configured to measure a flow parameter representative of the flow rate of plastic flowing, for example, within a plurality of delivery branches, more preferably within a supply duct. The control unit can be connected to the flow sensor to receive the flow parameter. The control unit can be programmed to drive one or more actuators in accordance with the flow parameter.

[0051] In one example, the apparatus comprises a compensation unit, which is preferably arranged upstream of a plurality of delivery branches of the distribution unit. The compensation unit may be in fluid communication with the supply duct. The compensation unit preferably defines a variable internal compensation volume, for example from a maximum volume configuration to a minimum volume configuration when the metering unit is in a discharge configuration, or from a minimum volume configuration to a maximum volume configuration when the metering unit is in a filling configuration. The purpose of the compensation unit is to compensate for fluctuations in the pressure exerted by the plastic when the outlet valve system or an additional valve system is in a closed configuration.

[0052] In one example, the apparatus comprises a compensation actuator connected to the compensation unit for varying the compensation volume, for example between a maximum volume configuration and a minimum value configuration.

[0053] In one example, the control unit is programmed to derive an imbalance parameter and preferably to drive one or more actuators according to the imbalance parameter. The imbalance parameter may represent an imbalance between plastic flows in a plurality of delivery branches, or an imbalance between plastic dosages, or an imbalance between molded objects.

[0054] The control unit may be connected to the plurality of outlet valves to synchronously control them. For example, the control unit may synchronously switch the plurality of outlet valves from an open configuration to a closed configuration, or vice versa. Further, the control unit may control the plurality of outlet valves to control each outlet valve independently of the others. For this purpose, the control unit may delay the opening and closing of the outlet valves, for example based on an imbalance parameter, a flow parameter or a check parameter.

[0055] In one example, the apparatus comprises an extruder. The extruder can be connected to a supply duct to supply a continuous flow of pressurized molten plastic to the supply duct. The apparatus may comprise a positive displacement pump disposed downstream of the extruder and connected to the supply duct to supply the pressurized molten plastic to the supply duct. The control unit can be programmed to control the extruder or the positive displacement pump according to one or more of a check parameter, a flow rate parameter, and an imbalance parameter. The purpose of the positive displacement pump is to keep the pressure at the inlet of the distribution unit constant.

[0056] Accordingly, the apparatus can be manufactured according to at least three approaches. In a first approach, the additional valve system preferably comprises a valve (main valve) disposed in the supply duct, which allows plastic to flow through the supply duct and allows the main partitioning element to move to an upper limit position to receive an amount of plastic (equal to the total of the dosages as a whole). In the first approach, the plastic starts from the distribution zone, is split between a plurality of branches, and the amount of plastic forming the dosage may be adjusted by a secondary partitioning element and then separated into dosages by an outlet valve system. In a second approach, the additional valve system is disposed in a plurality of delivery branches and separates the plastic flow only after the flow is split between the plurality of delivery branches starting from the distribution zone. Accordingly, in this second approach, the additional valve system comprises a plurality of valves, and the number of valves in the additional valve system is preferably equal to the number of delivery branches and the number of partitioning elements disposed in the delivery branches. Each partitioning element moves to an upper limit position to receive the corresponding dosage. In the second approach, as in the first approach, the outlet valve system then separates the plastic into dosages. Accordingly, these approaches differ, inter alia, in the position of the additional valve system.

[0057] Both approaches have the advantage of being able to provide a particularly accurate volumetric metering system that can tolerate fluctuations in the plastic flow delivered, for example, from the extruder, or more generally, fluctuations in the plastic flow upstream of the apparatus.

[0058] In a third approach, the plastic flow enters a supply duct and is split among a plurality of delivery branches. A plurality of partitioning elements disposed at the plurality of delivery branches move to an upper limit position while the outlet valve system is in a closed configuration to receive the plastic, and then, while the outlet valve system is in an open configuration, the plurality of partitioning elements move to a lower limit position to supply a dose towards an outlet. The outlet valve system returns to a closed configuration to block the plastic flow and form a dose. Compared with the first and second approaches, since there are no moving parts in the internal volume, the third approach provides a semi-volume metering system which preferably comprises a control unit for adjusting a plurality of partitioning elements (or, if present, an extruder or a positive displacement pump) based on check parameters, imbalance parameters or flow parameters to ensure that the doses are accurate and identical to each other.

[0059] This disclosure also relates to a method for manufacturing an object from a plastic material in a continuous cycle.

[0060] The method includes providing a distribution unit that may include a plurality of delivery branches each having an outlet. The method includes providing a supply duct having an inlet. The supply duct may communicate with the plurality of delivery branches via a distribution zone. Preferably, the distribution unit defines an internal volume between the inlet and the plurality of outlets. The method may include receiving raw plastic, for example, within an extrusion unit. The method may include supplying pressurized molten plastic, for example, from an extrusion unit, to the supply duct of the distribution unit. The method may include receiving the flow of molten plastic at the inlet of the supply duct, for example, from an extrusion unit. The method may include distributing the plastic flow from the inlet of the supply duct to the distribution zone of the distribution unit. The method may include distributing, i.e., splitting, the plastic flow to the plurality of delivery branches via the distribution zone.

[0061] The method includes the step of providing a metering unit including an outlet valve system. In one example, the outlet valve system includes a plurality of outlet valves. Each outlet valve may be arranged in a corresponding delivery branch.

[0062] In one embodiment, the method includes the step of providing a plurality of partitioning elements. Each partitioning element of the plurality of partitioning elements may be arranged in a corresponding delivery branch, preferably upstream of the corresponding outlet valve. Preferably, each partitioning element of the plurality of partitioning elements is movable between an upper limit position and a lower limit position, for example to change the internal volume of the distribution unit.

[0063] The method may include the step of providing a group of actuators.

[0064] Each actuator of the group of actuators may be connected to the corresponding partitioning element to move the corresponding partitioning element of the plurality of partitioning elements between an upper limit position and a lower limit position. In other words, the method may include the step of moving at least one of the plurality of partitioning elements between an upper limit position and a lower limit position by an actuator. The method may include the step of closing the outlet valve system, for example via a control unit, to block the flow of plastic delivered from the distribution unit. The method may include the step of controlling one or more actuators of the group of actuators, for example via a control unit, to move the corresponding partitioning element from a lower limit position to an upper limit position. The method may include the step of opening the outlet valve system, for example via a control unit, to allow plastic to be discharged from the internal volume of the distribution unit, and the step of controlling one or more actuators of the group of actuators, for example via a control unit, to move the corresponding partitioning element from an upper limit position to a lower limit position to generate a plurality of doses of plastic.

[0065] The method includes the step of providing an additional valve system. For example, the method includes the step of arranging an additional valve system upstream of the outlet valve system with respect to the supply direction of plastic from an inlet to an outlet. The internal volume may comprise an operating part included between the additional valve system and the outlet valve system, and the operating part is preferably variable from a contracted configuration having a minimum volume to an expanded configuration having a maximum volume. A plurality of partition elements may be movable between an upper limit position and a lower limit position to vary the operating part of the internal volume of the distribution unit. For example, when the plurality of partition elements are in the upper limit position, the operating part of the internal volume is in the expanded configuration, and when the plurality of partition elements are in the lower limit position, the operating part of the internal volume is in the expanded configuration.

[0066] The method may include the step of closing the outlet valve system and opening the additional valve system, for example via a control unit, so as to enable plastic to accumulate in the operating part of the internal volume. The method may include the step of separating, i.e., blocking, the flow of molten plastic via the additional valve system to form a predetermined amount of plastic. The method may include the step of closing the additional valve system and opening the outlet valve system, for example via a control unit, so as to enable plastic to be discharged from the operating part of the internal volume. While closing the additional valve system and opening the outlet valve system, the method may include the step of sending out a dose of plastic through the outlet. The method may include the step of separating, i.e., blocking, a predetermined amount of plastic into an additional predetermined amount of plastic via the outlet valve system to form a dose.

[0067] The method includes the step of supplying a dosage to a plurality of sheets of a plurality of female elements, preferably simultaneously, wherein the plurality of female elements can be arranged in a plurality of delivery branches. The method includes the step of compressing the dosage between a plurality of female elements and a corresponding plurality of male elements to form a plurality of objects of plastic material. In one example, the object is a parison intended to form a container by blow molding. Thus, the method may include the step of blow molding the object, i.e., the parison, to form the container.

[0068] In one example, the method may include the step of providing an outlet valve system including, for example, a plurality of pushers arranged in a plurality of delivery branches. Each pusher can reciprocate between a retracted position opening the corresponding delivery branch and a plurality of advanced positions closing the corresponding delivery branch. The method may include the step of moving the pusher in the extraction direction between the plurality of advanced positions. The method may include the step of extruding each dosage through a corresponding outlet by a corresponding pusher, for example while keeping the corresponding outlet valve closed. In other words, each pusher extrudes the corresponding dosage through the outlet while keeping the corresponding outlet valve closed when moving in the extraction direction between the plurality of advanced positions.

[0069] In one example, in addition to or instead of an outlet valve system, an additional valve system, and a plurality of partition elements, the method comprises providing a plurality of cutting devices, each cutting device being disposed at an outlet, opening each cutting device to enable plastic to be fed out from the outlet, and closing the outlet and closing each cutting device to separate the amount of plastic that forms a corresponding dose. The apparatus may comprise providing a plurality of sensors and, through each of the plurality of sensors, detecting in real time a flow parameter correlated with the flow rate of plastic in each delivery branch. The method may comprise receiving the flow parameter and closing and opening the cutting device according to the flow parameter. In one example, the method comprises closing during the step of opening and further opening first and second knives that act in conjunction to exchange positions and cut a dose at the outlet.

[0070] In one example, the method comprises controlling, via a control unit, the upper limit position of at least one of the plurality of partition elements. For example, the controlling step is performed for one of a series of shaping operations. Preferably, the control is based on parameters representing the previous shaping operation or a plurality of previous shaping operations. In other words, the method may comprise a step of feedback control. The parameter may be a check parameter, a flow parameter, or an imbalance parameter. In another example, the control is based on a check parameter representing the shaping operation during which the controlling step is performed. For example, the method may comprise a feedback control step of adjusting the amount of plastic that forms a dose. In one example, the method comprises moving a plurality of partition elements by an actuator or a group of actuators according to one or more of a check parameter, a flow parameter, and an imbalance parameter.

[0071] In one example, the method includes a step of processing check parameters. The processing step may be performed, for example, by an operator at the end of a molding cycle within the device, or may be performed during or at the end of the previous molding operation.

[0072] For example, the method may include a step of measuring the volume or mass of the dose delivered from the delivery branch using an optical sensor or a flow sensor. In one example, the method includes a step of moving each female element of a plurality of female elements along a longitudinal movement axis between a separation position where it does not interfere with the corresponding male element of a plurality of male elements and a proximity position where it closes a forming cavity with respect to the corresponding male element. The method may include a step of compressing the dose between each female element and the corresponding male element when the forming cavity is in the closed position.

[0073] The method may include a step in which each male element connected to an elastic element performs a sinking movement along the longitudinal movement axis following the compressing step. In one example, the method includes a step of deriving check parameters via a control unit, for example, in response to the step of the sinking movement. For this purpose, the method includes a step of adaptively moving the male element in proportion to the volume of the dose contained within the forming cavity. The method may include a step of measuring the distance of the sinking movement using a distance sensor. The method may include a step in which the control unit receives the distance of the sinking movement from the distance sensor. The method may include a step of processing the check parameters based on the distance received from the distance sensor in order to derive control parameters. The method may include a step of connecting to at least one partition element among a plurality of partition elements, or at least one actuator among a plurality of partition elements. The method may also include a step of controlling the upper limit position of at least one partition element among a plurality of partition elements using the control parameters.

[0074] In one example, the method includes a step of synchronously controlling a plurality of outlet valves via a control unit.

[0075] In one embodiment, the method includes supplying a continuous flow of pressurized molten plastic through an extruder or through a positive displacement pump disposed downstream of the extruder and connected to a supply duct, to the supply duct. The method may include controlling the extruder or the positive displacement pump via a control unit according to one or more of a check parameter, a flow rate parameter, and an imbalance parameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] These and other features will become more apparent from the following description of the preferred embodiments, shown by way of non-limiting example in the accompanying drawings.

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3E

Figure 3F

Figure 3G

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 5A - 5G

Figure 6A - 6H

DETAILED DESCRIPTION OF THE INVENTION

[0077] Referring to the accompanying drawings, the numeral 1 indicates an apparatus for manufacturing an object from a plastic material in a continuous cycle.

[0078] The apparatus 1 includes a dispensing unit 2. The dispensing unit 2 is configured to dispense a flow of molten plastic. The dispensing unit 2 includes a supply duct 201 having an inlet 202 and is preferably configured to receive a continuous flow of plastic from an extrusion unit 101. The extrusion unit 101 includes an inlet configured to receive plastic in an unprocessed form and to send out a flow of molten plastic. Preferably, the outlet of the extrusion unit 101 is disposed at the supply duct 201, i.e., the inlet 202, for receiving a flow of molten plastic, for example, a flow of molten plastic in a pressurized form. In one example, the extrusion unit 101 includes an extruder 101A and a positive displacement pump 101B, and the positive displacement pump 101B is disposed between the extruder 101A and the supply duct 201 and is configured to provide a pressurized flow of plastic.

[0079] The dispensing unit 2 includes a plurality of delivery branches 203. Each delivery branch 203 is in fluid communication with the supply duct 201 and receives the flow of plastic from the supply duct 201. For this purpose, between the supply duct 201 and the plurality of delivery branches 203, there is a distribution zone 204 configured to receive the flow of molten plastic from the supply duct 201 and distribute the flow of molten plastic to each of the plurality of delivery branches 203. In this way, the flow of plastic is divided among the plurality of delivery branches 203. Each delivery branch 203 includes an outlet 205 configured to supply plastic to the dispensing unit 2. The dispensing unit 2 defines an internal volume between the inlet 202 and the outlets 205 of the plurality of delivery branches 203.

[0080] Preferably, each delivery branch 203 includes a first branch 203A configured to receive plastic from the distribution zone 204 and a second branch 203B including the outlet 205. The first branch 203A and the second branch 203B communicate with each other and are preferably arranged perpendicular to each other such that plastic is supplied by gravity through the second branch 203B to the outlet 205. In one example, the distribution zone 204 comprises a first distribution zone 204A located downstream of the supply duct 201 and a second distribution zone 204B located downstream of the first distribution zone 204A. The first distribution zone 204A divides the flow of plastic from the supply duct 201 into a plurality of flows of plastic, and the second distribution zone 204B further divides each flow of the plurality of flows of plastic into a further plurality of flows, which are then received by the delivery branches 203.

[0081] The apparatus 1 comprises a metering unit 3 arranged within the dispensing unit 2 and configured to form a dosage to be delivered from the outlet 205 from the continuous flow of plastic supplied to the supply duct 201.

[0082] The metering unit 3 comprises an outlet valve system 302 that can be switched between a closed configuration and an open configuration. The outlet valve system 302 comprises a plurality of pushers 302A, and each pusher 302A is arranged in a corresponding delivery branch 203. More specifically, each pusher 302A is inserted into a second branch 203B and is reciprocally movable between a retracted position that does not interfere with the plastic flow within the second branch 203B and a plurality of advanced positions that close the corresponding second branch 203B. At the plurality of advanced positions, the pusher 302A is configured to extrude a corresponding dose through the outlet 205 by moving in an extraction direction between the advanced positions so as to keep the corresponding valve closed.

[0083] In one example, each pusher 302A includes an outer pusher 302B and an inner pusher 302C, and the outer pusher 302B is disposed outside the inner pusher 302C. That is, the outer pusher 302B surrounds the outside of the inner pusher 302C. Preferably, the outer pusher 302B and the inner pusher 302C are movable relative to each other. The pusher 302A may include an air duct 302D included between the outer pusher 302B and the inner pusher 302C. The air duct 302D is configured to allow the flow of air to pass through. For example, the outer pusher 302B and the inner pusher 302C can reciprocate (via axial translational movement) to communicate the air duct 302D with the outlet 205, for example, to allow the flow of air to exit through the outlet 205. In the retracted position, the outer pusher 302B and the inner pusher 302C cooperate to block the communication between the air duct 302D and the outlet 205. In at least one of the plurality of forward positions, the outer pusher 302B and the inner pusher 302C cooperate to communicate the air duct 302D with the outlet 205, and in particular to allow the flow of air to exit through the outlet 205. For example, in at least one of the plurality of forward positions at the front, the inner pusher 302C retracts relative to the outer pusher 302B, and the air duct 302D is connected to the outlet 205. For example, in at least one of the plurality of forward positions, the inner pusher 302C can move forward or backward, and as a result, the inner pusher 302C is pulled out (or retracted) relative to the outer pusher 302B so as to communicate the air duct 302D with the outlet 205.

[0084] The metering unit 3 comprises a plurality of partition elements 303, 303A, 303B each movable between an upper limit position X1 and a lower limit position X2. In the example shown in FIG. 3C as an example, the plurality of partition elements include a group of partition elements including a plurality of secondary partition elements 303B. Each partition element 303B of the plurality of secondary partition elements 303B is movable between the upper limit position X1 and the lower limit position X2 to change the internal volume of the dispensing unit 2 and is disposed within the corresponding delivery branch 203 upstream of the corresponding pusher 302A. The metering unit 3 includes a filling operation configuration in which the pusher 302A is in a closed configuration to block the flow of plastic delivered from the dispensing unit 2. In the filling configuration, the secondary partition element 303B is disposed at the upper limit position X1, and since the secondary partition element 303B is disposed at the upper limit position X1, the internal volume is in an expanded configuration, i.e., a maximum volume configuration. The metering unit 3 also includes a discharge operation configuration in which the additional valve system 301 is in a closed configuration and the secondary partition element 303B is disposed at the lower limit position X2 to enable the discharge of plastic from the internal volume and the delivery of the plastic dosage through the outlet 205. In the discharge configuration, since the secondary partition element 303B is disposed at the lower limit position X2, the internal volume is in a contracted configuration, i.e., a minimum volume configuration.

[0085] In one embodiment shown as an example in FIGS. 3A and 3B, the metering unit 3 comprises an additional valve system 301 with an outlet valve system 302, a plurality of partition elements 303, 303A, 303B, and a plurality of valves 301. The outlet valve system 302 is arranged downstream of the additional valve system 301 with respect to the supply direction of the plastic from the inlet 202 to the outlet 205 of the distribution unit 2. The additional valve system 301 can be switched between an open configuration and a closed configuration. In the open configuration, the additional valve system 301 allows the plastic to advance from the zone upstream of the additional valve system 301 to the zone downstream of the additional valve system 301. Similarly, in the open configuration, the outlet valve system 302 allows the plastic to advance from the zone upstream of the outlet valve system 302 to the zone downstream of the outlet valve system 302. Thus, when transitioning from the open configuration to the closed configuration, the additional valve system 301 and the outlet valve system 302 are configured to divide the flow of the molten plastic within the distribution unit 2.

[0086] The internal volume of the distribution unit 2 includes the operating part included between the additional valve system 301 and the outlet valve system 302.

[0087] The metering unit 3 includes a filling operation configuration in which the outlet valve system 302 is in the closed configuration and the additional valve system 301 is in the open configuration so as to allow the plastic to accumulate in the operating part. In the filling configuration, the partition elements 303, 303A, 303B are arranged at the upper limit position X1. Since the partition elements 303, 303A, 303B are arranged at the upper limit position X1, the internal volume is in an expanded configuration, that is, a maximum volume configuration. The metering unit 3 also includes a discharge operation configuration in which the additional valve system 301 is in the closed configuration, the outlet valve system 302 is in the open configuration, and the partition elements 303, 303A, 303B are arranged at the lower limit position X2 in order to allow the plastic to be discharged from the operating part of the internal volume and supply the plastic dosage through the outlet 205. In the discharge configuration, since the partition elements 303, 303A, 303B are arranged at the lower limit position X2, the operating part of the internal volume is in a contracted configuration, that is, a minimum volume configuration.

[0088] Generally speaking, the volume difference between the operating part in the extended configuration and the operating part in the contracted configuration is equal to the volume of one dose multiplied by the number of delivery branches 203 of the plurality of delivery branches 203.

[0089] In one embodiment shown as an example in FIG. 3A, the plurality of partition elements include a plurality of secondary partition elements 303B, each secondary partition element 303B is arranged in the corresponding delivery branch 203 of the plurality of delivery branches 203, and the additional valve system includes a plurality of valves 301 arranged upstream of the plurality of secondary partition elements 303B in the plurality of delivery branches 203. In this case, the operating part of the internal volume is located within the plurality of delivery branches 203.

[0090] In one embodiment shown as an example in FIG. 3B, the plurality of partition elements include a plurality of secondary partition elements 303B, each secondary partition element 303B is arranged in the corresponding delivery branch 203 of each of the plurality of delivery branches 203, and the main partition element 303A is arranged within the supply duct 201. The additional valve system 301 includes a main valve 301A arranged within the supply duct 201 of the distribution unit 2. More specifically, the main valve 301A is arranged upstream of the main partition element 303A. In this case, the operating part of the internal volume is located between the supply duct 201 and the plurality of delivery branches 203.

[0091] The volume of each dose is equal to the difference between the operating part in the extended configuration and the operating part in the contracted configuration divided by the number of delivery branches 203.

[0092] In an exemplary embodiment, each delivery branch 203 includes a secondary leg 207 configured to be in fluid communication with the corresponding delivery branch 203 and receive the corresponding partition element 303 (specifically, the corresponding secondary partition element 303B).

[0093] In one example, each secondary leg 207 and the corresponding delivery branch 203 are arranged perpendicular to each other (with respect to the flow direction of the plastic). In this example, the volume of one dose out of multiple doses is equal to the difference between the volume of the corresponding secondary leg 207 with the partitioning element 303 (or secondary partitioning element 303B) in the upper limit position X1 and the volume of the corresponding secondary leg 207 with the partitioning element 303 (or secondary partitioning element 303B) in the lower limit position X2.

[0094] In an example including the main partitioning element 303A disposed downstream of the main valve 301A, the supply duct 201 includes a main leg 206 configured to be in fluid communication with the supply duct 201 and receive the main partitioning element 303A. Preferably, the main leg 206 and the supply duct 201 are arranged perpendicular to each other.

[0095] The device 1 includes a control unit 5 configured to switch the metering unit 3 from the filling configuration to the discharging configuration with the plurality of partitioning elements 303, 303A, 303B in the lower limit position X2, and to switch from the discharging configuration to the filling configuration with the plurality of partitioning elements 303, 303A, 303B in the upper limit position X1.

[0096] The device 1 comprises a forming station 4 for compression molding. The forming station 4 includes a plurality of female elements 401 that can be arranged at a plurality of delivery branches 203 of the dispensing unit 2 in order to receive a plurality of doses being delivered from the outlet 205. The plurality of female elements 401 define a corresponding plurality of sheets 402 configured to receive the corresponding plurality of doses of the plastic being delivered. More specifically, in the discharge configuration, the additional valve system 301 is in a closed configuration and the outlet valve system 302 is in an open configuration in order to supply the doses to the plurality of sheets 402 of the plurality of female elements 401. The forming station 4 includes a plurality of male elements 403 that act in conjunction with the plurality of female elements 401, define a corresponding plurality of forming cavities, and are configured to simultaneously form a plurality of objects from a plastic material by compression. For this purpose, each female element 401 is movable along a longitudinal movement axis X between a spaced position that does not interfere with the corresponding male element 403 and a proximity position that acts in conjunction with the corresponding male element 403 to close the forming cavity in order to compress the dose. In one example, the control unit 5 is programmed to move each female element 401 along the longitudinal movement axis X.

[0097] In an exemplary embodiment, the object of the plastic material is a parison intended to form a container by subsequent blow molding. For this purpose, the device 1 may form part of a line 100 for manufacturing containers (e.g., for liquids or others) in a continuous cycle, and the manufacturing line 100 may comprise a parison blow molding station 102 for forming the container and an extrusion unit 101.

[0098] In one example, the control unit 5 is configured to open and close the additional valve system 301 and the outlet valve system 302.

[0099] In one example, the metering unit 3 comprises a plurality of actuators or a group of actuators 304, and each actuator 304 of the plurality of actuators or the group of actuators is connected to partition elements 303, 303A, 303B, specifically, the secondary partition element 303B disposed on the secondary leg 207, and moves them between an upper limit position X1 and a lower limit position X2. Alternatively, the partition elements 303, 303A, 303B, specifically the secondary partition element 303B, move under the action of the plastic pressure, that is, when the plurality of valves 301 or the main valve 301A are in the open position and the pusher 302A is in the closed position, the partition elements 303, 303A, 303B (or the secondary partition element 303B) are configured to move to the upper limit position X1, and when the plurality of valves are in the closed position and the pusher 302A is in the open position, the partition elements 303, 303A, 303B (or the secondary partition element 303B) are configured to move to the lower limit position X2 because the pressure exerted by the plastic on the partition elements 303, 303A, 303B is lower.

[0100] The upper limit position X1 is adjustable to change the maximum amount of plastic that can be accommodated in the working part of the internal volume, and more specifically to change the dosage volume.

[0101] The control unit 5 is programmed to drive the actuator and control the upper limit position X1 and the lower limit position X2 based on a check parameter, a flow rate parameter, or an imbalance parameter. When the extruder 101A and the positive displacement pump 101B are present, the control unit is programmed to control the extruder 101A and the positive displacement pump 101B according to a check parameter, a flow rate parameter, or an imbalance parameter. More specifically, for each delivery branch, the control unit 5 is programmed to receive a check parameter representing the difference between the volume or mass of one dose delivered from the delivery branch and a reference value of the volume or mass of the dose. In one example, the check parameter is derived by an optical sensor that measures the amount of plastic delivered from the outlet 205, or by a flow rate sensor that measures the flow rate of plastic in a plurality of delivery branches 203. The check parameter may represent a previous molding operation prior to the molding operation in which the upper limit position X1 or the lower limit position X2 is to be controlled. In other words, the control unit 5 is programmed to adjust the amount of plastic forming one dose by feedback. In another example, the check parameter is processed in real time for the molding operation and the position is checked during the same molding operation. The control unit 5 is programmed to process a control parameter based on the check parameter. The control unit 5 is connected to each actuator 304, transmits a control parameter, and adjusts the upper limit position X1 or the lower limit position X2 of the corresponding partition element based on the control parameter.

[0102] In one example, the metering unit 3 includes a primary actuator 305 connected to the main partition element 303A to move the main partition element 303A between the upper limit position X1 and the lower limit position X2. For example, the secondary partition element 303B moves between the upper limit position X1 and the lower limit position X2 by the pressure applied by the plastic. In another example, the main partition element 303A and the secondary partition element 303B move between the upper limit position X1 and the lower limit position X2 by the pressure applied by the plastic.

[0103] In one embodiment, each female element 401 of the plurality of female elements 401 is movable along the longitudinal movement axis X between a spaced position that does not interfere with the corresponding male element 403 of the plurality of male elements 403 and a proximity position that acts in conjunction with the corresponding male element 403 to close the formed cavity in order to compress the dose. Each male element 403 is connected to an elastic element 404 so that it can perform a sinking movement along the longitudinal movement axis X in response to the compression of the dose in the closed position of the formed cavity. Therefore, the sinking movement performed by the male element 403 is proportional to the size 406 of the volume of the dose to be compressed. For this purpose, the apparatus 1 comprises a sensor for measuring the distance 405 of the sinking movement. The control unit 5 is connected to the sensor in order to receive the distance 405 of the sinking movement and process the check parameters. The control unit 5 is programmed to process the control parameters based on the check parameters.

[0104] The control unit 5 is connected to each actuator 304, transmits control parameters, and adjusts the upper limit position X1 of the corresponding partition elements 303, 303A, 303B.

[0105] Preferably, each male element 403 comprises a punch 412, a structure 413, a first abutting element 407 connected to the structure 413 by a first elastic element 404, and a second abutting element 408 connected to the structure by a second elastic element 410. When the female element 402 is in the proximity position, the first abutting element 407 is configured to abut against the second abutting element 408, the second abutting element 408 is configured to abut against the forming abutting surface 409 of the punch 412, and the punch 412 is configured to perform a sinking movement along the longitudinal movement axis X. More specifically, the sinking movement includes a distance 405 that is proportional to the size 406 of the volume of one dose. The control unit 5 is configured to process the control parameters according to the distance 405 of the sinking movement and adjust the upper limit position X1 by the adjustment distance 411 of the partition elements 303, 303A, 303B.

[0106] In one embodiment, the apparatus comprises a flow sensor configured to capture a flow parameter representative of the flow rate of plastic flowing within supply duct 201. The control unit 5 is connected to the flow sensor to receive the flow parameter and drive the actuator 304 and, alternatively or additionally, the main actuator 305, based on the flow parameter, in particular based on control parameters processed according to the flow parameter.

[0107] In one embodiment, the apparatus 1 comprises a compensation unit 208 disposed within the supply duct 201. The compensation unit 208 may be disposed upstream of the plurality of delivery branches 203 within the supply duct 201 and in the supply direction of the plastic from the inlet 202 to the outlet 205. If the main valve 301A is present, the compensation unit 208 is disposed upstream of the main valve 301A. If a plurality of valves 301 are present, the compensation unit 208 is disposed upstream of the plurality of valves 301. The compensation unit 208 defines a variable internal compensation volume from a maximum volume configuration to a minimum volume configuration with the metering unit 3 in the discharge configuration and from the minimum volume configuration to the maximum volume configuration with the metering unit 3 in the filling configuration. The compensation unit 208 includes a compensation partitioning element 306. The compensation partitioning element 306 is movable, preferably freely, within the compensation unit 208 under the pressure applied by the inflowing plastic in order to vary the amount of plastic contained within the compensation volume. It should be noted that the purpose of the compensation unit 208 is to compensate for pressure fluctuations when the main valve 301A or the plurality of valves 301 are in the closed configuration. In one example, the compensation unit 208 is disposed within the extrusion unit 101. For this purpose, the extrusion unit 101 has a variable volume downstream of its screw feeder, which is configured, for example, to retract to define the compensation volume. In an example not shown, the compensation unit may comprise a compensation actuator to vary the compensation volume between a maximum volume configuration and a minimum value configuration.

[0108] A method for manufacturing an object from a plastic material in a continuous cycle includes providing a dispensing unit 2 including a plurality of delivery branches 203 each having an outlet 205 and a supply duct 201 having an inlet 202 and communicating with the plurality of delivery branches 203 through a dispensing zone 204. The method includes receiving a pressurized stream of molten plastic at the inlet 202 from an extrusion unit 101, the extrusion unit preferably comprising an extruder 101A and a positive displacement pump 101B.

[0109] The method includes providing a metering unit 3.

[0110] In one example, the step of providing a metering unit 3 includes the following sub-steps. That is, - A sub-step of arranging an outlet valve system including a plurality of pushers 302A downstream of a plurality of partition elements 303, each pusher 302A being arranged in a second branch 203B of a corresponding delivery branch 203; - a sub-step of arranging a plurality of secondary partition elements 303B on a corresponding plurality of secondary legs 207 perpendicular to a first branch 203A of a corresponding delivery branch 203 downstream of a plurality of valves with respect to the supply direction of plastic from the inlet 202 to the outlet 205, and the method includes a step of supplying a flow of molten plastic from the supply duct 201 to the distribution zone 204, and a step of distributing, that is, splitting, the flow of molten plastic from the distribution zone 204 to a plurality of delivery branches 203. On the one hand, each secondary partition element 303B is moved, for example, by an actuator 304 to a upper limit position X1, that is, a position where the internal volume of the distribution unit 2 is in an expanded configuration, that is, a maximum volume configuration. When the secondary partition element 303B of the delivery branch 203 reaches its upper limit position X1, the control unit 5 opens the corresponding pusher 302A, and the pusher 302A moves to a retracted position to open a passage for the plastic in the second branch 203B. The plastic contained in the internal volume advances in the second branch 203B while the secondary partition element 303B migrates from the upper limit position X1 to a lower limit position X2, where the internal volume is in a contracted or minimum volume configuration. When the secondary partition element 303B reaches the lower limit position X2, the control unit 5 closes the pusher 302A, and the pusher 302A moves from the retracted position in the extraction direction towards a plurality of forward positions. When moving between the plurality of forward positions in the extraction direction, the pusher 302A separates the plastic contained in the second branch 203B from the plastic contained in the first branch 203A by closing the passage for the plastic in the second branch 203B. When moving in the extraction direction, the pusher 302A also pushes the plastic contained in the second branch 203B. In this way, the pusher 302A forms a dose. The dose exits through the corresponding outlet 205 and is supplied by gravity to a sheet 402 of one of the plurality of female elements 401 of the female element 401. Therefore, when the plastic advances from the inlet 202 to the plurality of outlets 205, it undergoes a first (parallel) separation performed by the distribution zone 204 and a second (serial) separation performed by the plurality of pushers 302A.

[0111] In one example, each pusher 302A includes an outer pusher 302B and an inner pusher 302C, and the outer pusher 302B is disposed outside the inner pusher 302C (the outer pusher 302B surrounds the outside of the inner pusher 302C). Preferably, the outer pusher 302B and the inner pusher 302C are movable relative to each other. The pusher 302A may include an air duct 302D included between the outer pusher 302B and the inner pusher 302C. The air duct 302D is configured to allow the flow of air to pass through. For example, the outer pusher 302B and the inner pusher 302C can reciprocate (via axial translational movement) to communicate the air duct 302D with the outlet 205, for example, to allow the flow of air to exit through the outlet 205. In the retracted position, the outer pusher 302B and the inner pusher 302C cooperate to block the communication between the air duct 302D and the outlet 205. In at least one forward position of the plurality of forward positions, the outer pusher 302B and the inner pusher 302C cooperate to communicate the air duct 302D with the outlet 205, and in particular to allow the flow of air to exit through the outlet 205. For example, in at least one forward position of the plurality of forward positions, the inner pusher 302C moves rearward or is withdrawn relative to the outer pusher 302B to communicate the air duct 302D with the outlet 205.

[0112] Accordingly, in one forward position of the plurality of forward positions of the pusher 302A, the inner pusher 302C moves to a retracted position or an extraction position relative to the outer pusher 302B, opening a passage for the air flow from the outlet 205 and the air duct 302D. The air flow exits from the air duct 302D to separate the dose 20. Subsequently, the dose 20 exits through the corresponding outlet 205 and falls by gravity onto the sheet 402 of one of the plurality of female elements 401 of the female element 401.

[0113] When each sheet 402 receives the corresponding plastic dosage, the plurality of female elements 401 move along the longitudinal movement axis X between a spaced position where they do not interfere with the corresponding male elements 403 and a proximity position where each of them closes the forming cavity with respect to the male elements 403. The method includes a step of compressing the dosage, in which step each female element 402 and the corresponding male element 403 form an object by compression by approaching each other.

[0114] In one example, the method includes the step of arranging an additional valve system 301 including a plurality of valves 301, each of the plurality of valves 301 being arranged in a first branch 203A of a corresponding delivery branch 203. The method includes the step of opening the plurality of valves 301 via a control unit 5. After opening the plurality of valves, the molten plastic advances and accumulates in the working part of the internal volume of the distribution unit 2, i.e., the part between the plurality of valves 301 and the plurality of pushers 302A. On the other hand, each secondary partition element 303B is moved, for example, by an actuator 304 to an upper limit position X1, i.e., a position where the working part is in an extended configuration, i.e., a maximum volume configuration. When the secondary partition element 303B of the delivery branch 203 reaches its upper limit position X1, the control unit 5 closes the corresponding valve 301 and opens the corresponding pusher 302A, and the pusher 302A moves to a retracted position to open a passage for the plastic in the second branch 203B. The plastic contained in the working part of the internal volume advances in the second branch 203B while the secondary partition element 303B migrates from the upper limit position X1 to a lower limit position X2, where the working part is in a contracted or minimum volume configuration. When the secondary partition element 303B reaches the lower limit position X2, the control unit 5 closes the pusher 302A, and the pusher 302A separates and extrudes to form a dose, and the dose is sent out and falls onto the sheet 402. In this example, while the pusher 302A is closed, i.e., during the movement of the pusher 302A in the extraction direction, the control unit 5 opens the valve 301 again, enabling the plastic to accumulate in the working part again. Thus, when the plastic advances from the inlet 202 to the plurality of outlets 205, it undergoes a first (parallel) separation performed by the distribution zone 204, a second (serial) separation performed by the plurality of valves 301, and a third (serial) separation performed by the plurality of pushers 302A.

[0115] In one example, the method includes placing an additional valve system 301 including a main valve 301A within a supply duct 201, and placing a main partition element 303A within the supply duct downstream of the main valve 301A and within a main leg 206. The method includes opening the main valve 301 via a control unit 5. After opening the main valve 301A, molten plastic advances and accumulates in the operating portion of the internal volume of the dispensing unit 2, i.e., the portion between the main valve 301A and the pusher 302A. On the other hand, the main partition element 303A and the secondary partition element 303B move to an upper limit position X1, i.e., a position where the operating portion is in an expanded configuration, i.e., a maximum volume configuration. For example, the secondary partition element 303B is moved by an actuator 304 and the main partition element 303A is moved by a main actuator 305. When the secondary partition element 303B and the main partition element 303A of the delivery branch 203 reach their respective upper limit positions X1, the control unit 5 closes the main valve 301A and opens the corresponding pusher 302A, and the pusher 302A moves to a retracted position to open a passage for the plastic within the second delivery branch 203B. The plastic contained in the operating portion of the internal volume advances within the second branch 203B while the partition element moves from the upper limit position X1 to a lower limit position X2, where the operating portion is in a contracted configuration, or a minimum volume configuration. When the partition element reaches the lower limit position X2, the control unit 5 closes the pusher 302A and the pusher 302A separates and extrudes to form a dose, and the dose is delivered and falls onto the sheet 402. In this example, while the pusher 302A is closed, i.e., during the movement of the pusher 302A in the extraction direction, the control unit 5 opens the main valve 301A again to allow the plastic to accumulate again in the operating portion. Thus, as the plastic advances from the inlet 202 to the plurality of outlets 205, the plastic undergoes a first (serial) separation performed by the main valve 301A, a second (parallel) separation performed by the distribution zone 204, and a third (serial) separation performed by the plurality of pushers 302A.

[0116] In one embodiment, the method includes a calibration (or adjustment) step based on a previous molding operation or the same molding operation to adjust the volume of the dose for one of a series of molding operations.

[0117] Preferably, in one or more embodiments, the pushers 302A are synchronized with each other such that each pusher 302A reaches the closed position of the corresponding valve simultaneously with the other pushers 302A. In this way, the doses fall simultaneously onto the plurality of sheets 402, and the plurality of female die elements 401 can move towards the plurality of male die elements 402 and act in conjunction with the plurality of male die elements 402 to compress the plurality of doses. Alternatively, the pushers 302A are controlled to open and close independently of each other, for example, to adjust the amount of plastic being delivered.

[0118] In one embodiment, following the steps of moving and compressing the dose, the method includes the step of each male element 403 connected to the elastic element 404 performing a sinking motion along the longitudinal movement axis X. The sinking motion is proportional to the size 406 of the volume of the dose disposed in the sheet of the corresponding female element 402. More specifically, the distance 405 of the sinking motion is proportional to the volume 406 of the dose, or a value derived therefrom. The method includes the step of detecting the distance 405 of the sinking motion via a distance sensor and transmitting the distance 405 to the control unit 5. Preferably, the control unit 5 receives the distance 405 and compares the distance 405 with a predetermined distance representing the optimal distance proportional to the optimal volume of the dose. The control unit 5 processes a check parameter representing the comparison result and processes a control parameter based on the check parameter. The control unit 5 transmits the control parameter to the actuator 304 connected to the secondary partition element 303B to adjust the upper limit position X1. More specifically, if the value of the distance 405 is less than the predetermined distance, and thus the volume of the dose is less than the optimal dose volume, the control unit 5 processes the control parameter to correct the upper limit position X1, for example, by the adjustment distance 411, to guide a larger amount of plastic to the secondary leg 207 compared to the previous molding operation. If the value of the distance 405 is greater than the predetermined distance, and thus the volume of the dose is greater than the optimal dose volume, the control unit 5 processes the control parameter to correct the upper limit position X1 to guide a smaller amount of plastic to the secondary leg 207 compared to the previous molding operation.

[0119] Preferably, the method includes the step of abutting following the movement of the female element 401 towards the first abutting element 407 connected to the structure 413 of the male element 403 via the first elastic element 404, and the step of abutting against the second abutting element 408 connected to the structure of the male element 403 via the second elastic element 408. Following the abutment of the second abutting element 408, the punch 412 of the male element 403 performs a sinking motion along the longitudinal movement axis X of the distance 405.

[0120] In one embodiment, the control unit 5 processes check parameters. The check parameters represent the difference between the volume or mass of a dose delivered from the delivery branch and the reference value of the volume or mass of the dose. The method includes the step of measuring, with a sensor, the volume or mass of the dose delivered. Next, the control unit 5 processes the control parameters of the actuator based on the check parameters.

[0121] In another example, the control unit 5 processes the control parameters based on a flow parameter, i.e., a parameter representing the flow rate of plastic in the supply duct. In another example, the control unit 5 processes the control parameters based on an imbalance parameter representing the imbalance between the flow rates of plastic in the plurality of delivery branches 203, and drives the actuator of the partition element based on the imbalance parameter. Preferably, the control unit 5 transmits the control parameters to the extruder 101A or the positive displacement pump 101B to adjust the flow of plastic supplied to the supply duct 201.

[0122] The following paragraphs are enumerated in alphanumeric order for reference purposes and are non-limiting exemplary forms for explaining the present invention. A. An apparatus (1) for manufacturing an object from a plastic material in a continuous cycle, - A distribution unit (2), A supply duct (201) having an inlet (202) configured to receive a continuous pressurized flow of molten plastic from an extrusion unit, and a plurality of delivery branches (203) in fluid communication with the supply duct (201) via a distribution zone (204), each delivery branch (203) having an outlet (205), the distribution unit (2) defining an internal volume between the inlet (202) and the outlet (205); - A forming station (4) for forming a plurality of objects by compression molding, A plurality of female die elements (401) that can be arranged on the plurality of delivery branches (203) of the distribution unit (2) and define a corresponding plurality of sheets (402); To form a plurality of objects from a plastic material by compression, a forming station (4) including a plurality of male die elements (403) acting in conjunction with a plurality of female die elements (401) to define a corresponding plurality of forming cavities. - A metering unit (3) configured to simultaneously form a plurality of doses from a continuous flow of plastic to supply each dose of the plurality of doses to each female die element (401) of the plurality of female die elements, the metering unit (3) including an outlet valve system (302) having a plurality of outlet valves, each outlet valve being disposed in a corresponding delivery branch (203) and being switchable between an open configuration and a closed configuration. A1. The metering unit (3) includes the following operating configurations, namely, A filling configuration in which the outlet valve system (302) is in a closed configuration to block the flow of plastic delivered from the distribution unit (2). An ejection configuration in which the outlet valve system (302) is in an open configuration to allow plastic to be ejected from the internal volume of the distribution unit (2). - The apparatus according to paragraph A, comprising a control unit (5) configured to switch the metering unit (3) from the filling configuration to the ejection configuration and vice versa. A1.1. The metering unit (3) includes a plurality of partition elements (303, 303A, 303B) disposed upstream of the outlet valve system (302), each of the plurality of partition elements (303, 303A, 303B) being movable between an upper limit position (X1) and a lower limit position (X2) to change the internal volume of the distribution unit (2), and the plurality of partition elements including a group of partition elements disposed downstream of the supply unit (201). The plurality of partition elements (303, 303A, 303B) Move from the upper limit position (X1) to the lower limit position (X2) in the ejection configuration. Move from the lower limit position (X2) to the upper limit position (X1) in the filling configuration. The apparatus according to paragraph A1. A1.1.1. The metering unit (3) comprises actuators (304, 305) configured to actuate the movement of corresponding partition elements between an upper limit position (X1) and a lower limit position (X2) for at least one of a plurality of partition elements (303, 303A, 303B), the actuators being driven by a control unit, the device according to paragraph A1.1. A1.1.2. The metering unit (3) comprises an additional valve system (301) arranged upstream of the outlet valve system (302) with respect to the supply direction of plastic from the inlet (202) to the outlet (205) and being switchable between an open configuration and a closed configuration. The plurality of partition elements (303, 303A, 303B) are arranged between the additional valve system (301) and the outlet valve system (302), and the internal volume includes the operating part included between the additional valve system (301) and the outlet valve system (302). Each of the plurality of partition elements (303, 303A, 303B) is movable between an upper limit position (X1) and a lower limit position (X2) to change the operating part of the internal volume of the dispensing unit (2). When the metering unit (3) is in the filling configuration, the additional valve system (301) is in the open configuration to enable plastic to accumulate in the operating part of the internal volume of the dispensing unit. When the metering unit (3) is in the discharging configuration, the additional valve system (301) is in the closed configuration to discharge plastic from the operating part of the internal volume and send the dose through the outlet (205) to supply the dose to the plurality of sheets (402) of the plurality of female elements (401), the device according to paragraph A1.1 or A1.1.1. A1.1.3. At least one of the plurality of partition elements (303, 303A, 303B) defines a plurality of secondary partition elements (303B), and each partition element of the plurality of secondary partition elements (303B) is arranged in a corresponding delivery branch (203) of the plurality of delivery branches, the device according to any one of A1.1.2 from paragraph A1.1. A1.1.4. The device according to any one of paragraphs A1.1 to A1.1.3, wherein the plurality of partition elements (303, 303A, 303B) comprises a main partition element (303A) arranged in the supply duct (201) of the dispensing unit (2). A1.1.5. The device according to any one of paragraphs A1.1 to A1.1.4, wherein the upper limit position (X1) of at least one of the plurality of partition elements (303, 303A, 303B) is adjustable to vary the maximum amount of plastic that can be accommodated in the working part of the internal volume. A1.1.5.1. For each dispensing branch, the control unit is programmed to receive a check parameter and adjust the upper limit position (X1) of at least one dividing element of the plurality of partition elements (303, 303A, 303B) according to the check parameter, the check parameter representing the difference between the volume or mass of a single dose dispensed from the dispensing branch and a reference value of the volume or mass of said dose, the device according to paragraph A1.1.5. A1.1.5.1.1. Each of the plurality of female elements (401) is movable along the longitudinal movement axis (X) between a spaced position where it does not interfere with the corresponding male element of the plurality of male elements (403) and a proximity position where it acts in conjunction with the corresponding male element (403) to close the forming cavity for compressing the dose, each male element (403) being connected to an elastic member (404) so as to be able to perform a sinking movement along the longitudinal movement axis (X) in response to the compression of the dose in the closed position of the forming cavity, the check parameter being derived in response to the sinking movement, the device according to paragraph A1.1.5.1. A1.1.5.2. The control unit is programmed to receive a flow parameter for each dispensing branch and adjust the upper limit position (X1) of at least one of the plurality of partition elements (303, 303A, 303B) according to the flow parameter, the device comprising a flow sensor configured to measure a flow parameter representing the flow rate of plastic flowing in the dispensing branch, the control unit being connected to the sensor for receiving the flow parameter, the device according to paragraph A1.1.5. A1.2. A device according to any one of paragraphs A1.1 to A1.1.5, comprising a sensor system including a plurality of sensors, each of the plurality of sensors being configured to detect in real time a flow rate parameter correlated with the flow rate of plastic within each delivery branch (203), the control unit (5) being connected to the sensor system and the outlet valve system (302) and driving the outlet valve (302) according to the flow rate parameter. A1.2.1. The device according to paragraph A1.2, wherein the flow rate parameter represents the length of a section of plastic extruded through each outlet (205) and disposed outside the distribution unit (2). A2. The outlet valve system (302) comprises a plurality of pushers (302A), each pusher (302A) being reciprocally movable between a retracted position that is disposed in the corresponding delivery branch (203) and does not impede the flow of plastic within the corresponding delivery branch (203), and a plurality of advanced positions that close the corresponding delivery branch (203), and the pusher (302A) being configured to push a corresponding dosage through the outlet (205) by moving in the extraction direction between the plurality of advanced positions so as to keep the corresponding outlet valve closed. A device according to any one of paragraphs A to A1.1.5. A3. The outlet valve system (302) comprises a plurality of cutting devices, each cutting device being switchable between an open configuration that is disposed at the outlet (205) and enables plastic to be sent out from the outlet (205), and a closed configuration that closes the outlet (205) and is configured to separate the amount of plastic forming the corresponding dosage. A device according to any one of paragraphs A to A1.1.5. A3.1. Each cutting device comprises a first knife and a second knife, each of the first knife and the second knife including a first blade and a second blade disposed on both sides of the knife with respect to the moving direction of the knife, the first knife and the second knife being juxtaposed with each other along the moving direction, and the first knife and the second knife being movable relative to each other to exchange positions between a further open position and an open position via an open position and a closed position when moving from the open position to the further open position, the device according to paragraph A3. A3.1.1. In the closed position of the first and second knives, the first and second knives are configured to act in conjunction to cut the dose at the outlet, the device according to paragraph A3.1. B. A method for manufacturing an object from a plastic material in a continuous cycle, - A dispensing unit (2) including a plurality of delivery branches (203) each having an outlet (205) and a supply unit (201) having an inlet (202) communicating with the plurality of delivery branches (203) via a distribution zone (204), the step of providing a dispensing unit (2) defining an internal volume between the inlet (202) and the outlet (205); - The step of receiving a flow of molten plastic at the inlet (202) of the supply duct (201) from an extrusion unit; - The step of distributing the flow of plastic to the plurality of delivery branches (203) via the distribution zone (204); - The step of providing a metering unit (3); - The step of forming a plurality of doses from a continuous flow of plastic using a metering unit (3) via an outlet valve system (302) having a plurality of outlet valves, each outlet valve being disposed in a corresponding delivery branch (203) and switchable between an open position and a closed position; - The step of simultaneously supplying each dose of the plurality of doses to each of a plurality of female elements (401) disposed in the plurality of delivery branches (203); -Compressing the dosage between a plurality of female elements (401) and a corresponding plurality of male elements (403) to form objects of a plurality of plastic materials. B1. Including the following steps executed by the control unit (5), namely -Switching the metering unit (3) from a filling configuration that enables blocking the flow of plastic sent from the dispensing unit (2) to a discharging configuration that enables discharging the plastic from the internal volume and supplying the dosage to the plurality of sheets (402) of the plurality of female elements (401) via the outlet (205). -Switching the metering unit (3) from the discharging configuration to the filling configuration. The method according to paragraph B, wherein the outlet valve system is in a closed configuration when the metering unit (3) is in the filling configuration and in an open configuration when the metering unit (3) is in the discharging configuration. B1.1. -Providing a plurality of partitioning elements (303, 303A, 303B) of the metering unit (3), each of the plurality of partitioning elements (303, 303A, 303B) being movable between an upper limit position (X1) and a lower limit position (X2) to change the internal volume of the dispensing unit (2), and the plurality of partitioning elements (303, 303A, 303B) including a group of partitioning elements arranged downstream of the supply duct (201). -Moving at least one of the plurality of partitioning elements (303, 303A, 303B) between the upper limit position (X1) and the lower limit position (X2), preferably by actuators (304, 305). The plurality of partitioning elements (303, 303A, 303B) are Moving from the upper limit position (X1) to the lower limit position (X2) in the discharging configuration, Moving from the lower limit position (X2) to the upper limit position (X1) in the filling configuration. The method according to paragraph B1. B1.1.1. The metering unit (3) includes an additional valve system (301) arranged upstream of the outlet valve system (302) with respect to the supply direction of plastic from the inlet (202) to the outlet (205), and the working part of the internal volume included between the additional valve system (301) and the outlet valve system (302) is variable from a contracted configuration having a minimum volume to an expanded configuration having a maximum volume. The method further includes the following steps performed by the control unit (5), namely, closing the outlet valve system (302) and opening the additional valve system (301) while the metering unit (3) is in the filling configuration; closing the additional valve system (301) and opening the outlet valve system (302) while the metering unit (3) is in the discharging configuration, the method according to paragraph B1.1. B1.1.2. The upper limit position (X1) of at least one of the plurality of partition elements (303, 303A, 303B) is adjusted by the control unit to vary the maximum amount of plastic that can be accommodated in the working part of the internal volume, the method according to any one of paragraphs B1.1 to B1.1.1. B1.1.2.1. The control unit receives (preferably for each delivery branch) a check parameter and adjusts the upper limit position (X1) of at least one of the plurality of partition elements (303, 303A, 303B) according to the check parameter, the check parameter representing the difference between the volume or mass of a single dose delivered from the delivery branch and a reference value of the volume or mass of that dose, the method according to paragraph B1.1.2. B1.1.2.1.1. Each of the plurality of female elements (401) is movable along a longitudinal movement axis (X) between a spaced position that does not interfere with the corresponding male element of the plurality of male elements (403) and a proximity position that acts in conjunction with the corresponding male element (403) to close the forming cavity in order to compress the dosage. Each male element (403) is connected to an elastic element (404) capable of performing a sinking movement along the longitudinal movement axis (X) in response to the compression of the dosage in the closed position of the forming cavity. The control unit derives a check parameter in response to the sinking movement, according to the method described in paragraph B1.1.2.1. B1.1.2.2. The control unit receives (preferably for each delivery branch) a flow parameter representing the flow rate of plastic flowing in the device (preferably in the delivery branch), and adjusts the upper limit position (X1) of at least one of the plurality of partition elements (303, 303A, 303B) according to the flow parameter, according to the method described in paragraph B1.1.2. B1.2. The method includes the step of providing a sensor system including a plurality of sensors. Each of the plurality of sensors detects in real time a flow parameter correlated with the flow rate of plastic in each delivery branch (203). The control unit (5) is connected to the sensor system and the outlet valve system (302) and drives the outlet valve (302) according to the flow parameter, according to any one of the methods described in paragraphs B1.1 to B1.1.2.2. B1.2.1. The flow parameter represents the length of the section of plastic extruded through each outlet (205) and disposed outside the dispensing unit (2), according to the method according to paragraph B1.2. B2. The outlet valve system (302) includes a plurality of pushers (302A) arranged in a plurality of delivery branches (203), each pusher (302A) reciprocating between a retracted position opening the corresponding delivery branch (203) and a plurality of advanced positions closing the corresponding delivery branch (203), such that the pusher (302A) moves in the extraction direction between the advanced positions to keep the corresponding outlet valve closed while pushing out the corresponding dose through the outlet (205), the method according to any one of paragraphs B to B1.2.1. B3. The outlet valve system (302) includes a plurality of cutting devices, each cutting device being arranged at the outlet (205), the method comprising: - opening each cutting device to enable plastic to be fed out of the outlet (205); - closing each cutting device to close the outlet (205), thereby separating the amount of plastic forming the corresponding dose, the method according to any one of paragraphs B to B2. B3.1. Each cutting device is configured to define a shutter by closing the corresponding outlet, the method according to paragraph B3. B3.1.1. Each cutting device is connected to a control unit, the control unit controlling the working cycle and determining the closing time (during which the cutting device / shutter is closed) and the opening time (during which the cutting device / shutter is open), the method according to paragraph B3.1. B3.1.1.1. The control unit manages the cutting device / shutter in different ways so as to be able to set different working cycles for different cutting devices / shutters, the method according to paragraph B3.1.1. B3.2. - providing a sensor system including a plurality of sensors; - detecting in real time, via each of the plurality of sensors, a flow parameter correlated with the flow rate of plastic within each delivery branch (203), the flow parameter representing the length of the section of plastic extruded through each outlet (205) and arranged outside the dispensing unit (2). Receiving a flow parameter via a cutting device and a control unit (5) connected to a sensor system, closing the cutting device according to the flow parameter, and opening the cutting device, the method according to any one of paragraphs B3 to B3.1.1.1. B3.3. Each cutting device includes a first knife and a second knife. The first knife and the second knife each include a first blade and a second blade disposed on both sides of the knife with respect to the moving direction of the knife. The first knife and the second knife are juxtaposed with each other along the moving direction. The method includes opening the first knife and the second knife, and closing during the step of further opening the first knife and the second knife. The first knife and the second knife exchange positions and act in conjunction to cut the dosage at the outlet, the method according to any one of paragraphs B3 to B3.2.

Prior Art Documents

Patent Documents

[0123]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Claims

1. An apparatus (1) for manufacturing objects from a plastic material in a continuous cycle, comprising: - A dispensing unit (2), comprising: A supply duct (201) having an inlet (202) configured to receive a continuous pressurized flow of molten plastic, and a plurality of delivery branches (203), each delivery branch (203) having an outlet (205) and being in fluid communication with the supply duct (201) via a distribution zone (204), the dispensing unit (2) defining an internal volume between the inlet (202) and the outlet (205); - A forming station (4) for forming a plurality of objects by compression molding, comprising: A plurality of female die elements (401) that can be arranged on the plurality of delivery branches (203) of the dispensing unit (2) and define a corresponding plurality of sheets (402), and A plurality of male die elements (403) that act in conjunction with the plurality of female die elements (401) to define a corresponding plurality of forming cavities for forming a plurality of objects from the plastic material by compression; - A metering unit (3), comprising: An outlet valve system having a plurality of outlet valves (302), each outlet valve being arranged in a corresponding delivery branch (203), the outlet valve system being switchable between an open configuration and a closed configuration, and A plurality of partition elements, each of the plurality of partition elements being arranged in the corresponding delivery branch upstream of the corresponding outlet valve and being movable between an upper limit position (X1) and a lower limit position (X2) to change the internal volume of the dispensing unit (2), and A group of actuators, each actuator of the group of actuators being connected to a corresponding partition element of the plurality of partition elements and moving it between the upper limit position (X1) and the lower limit position (X2), The metering unit (3) including the following operating configurations, namely: A filling configuration in which the outlet valve system (302) is in the closed configuration to block the flow of plastic delivered from the dispensing unit (2); A discharge configuration, wherein the outlet valve system (302) is in the open configuration to enable plastic to be discharged from the internal volume of the dispensing unit (2), and a discharge configuration, including a metering unit (3); - A control unit (5), Switching the metering unit (3) from the filling configuration to the discharge configuration and from the discharge configuration to the filling configuration, Driving one or more of the group of actuators to move the corresponding partition element from the upper limit position (X1) to the lower limit position (X2) with the metering unit (3) in the discharge configuration, and from the lower limit position (X2) to the upper limit position (X1) with the metering unit (3) in the filling configuration to form a plurality of doses of plastic, and the doses are supplied to the plurality of sheets (402). A control unit (5) configured as described above, and an apparatus (1) comprising the control unit.

2. For each delivery branch, the control unit is programmed to receive a check parameter and drive the one or more actuators according to the check parameter, and the check parameter represents the difference between the volume or mass of one dose delivered from the delivery branch and the reference value of the volume or mass of the dose. The apparatus according to claim 1.

3. Each of the plurality of female elements (401) is movable along the longitudinal movement axis (X) between a separation position where it does not interfere with the corresponding male element of the plurality of male elements (403) and a proximity position where it acts in conjunction with the corresponding male element (403) to close the forming cavity for compressing the dose. Each male element (403) is connected to an elastic element (404) so as to be able to perform an adaptive movement along the longitudinal movement axis (X) in response to the compression of the dose at the closed position of the forming cavity, and the check parameter is derived according to the adaptive movement. The apparatus according to claim 2.

4. Comprising a flow sensor configured to measure a flow parameter representing the flow rate of the plastic flowing in the supply duct, and the control unit is connected to the sensor to receive the flow parameter. The apparatus according to any one of claims 1 to 3.

5. The device according to claim 4, wherein the control unit is programmed to drive one or more of the actuators according to the flow rate parameter.

6. The outlet valve system comprises a plurality of pushers (302A), each pusher (302A) being arranged in a corresponding delivery branch (203) and being reciprocally movable between a retracted position that does not interfere with the flow of plastic in the corresponding delivery branch (203) and a plurality of advanced positions that close the corresponding delivery branch (203), the pusher (302A) being configured to extrude a corresponding dose through the outlet (205) by moving in the extraction direction between the plurality of advanced positions so as to keep the corresponding delivery branch (203) closed. The device according to any one of claims 1 to 5.

7. The device according to any one of claims 1 to 6, comprising a compensation unit arranged upstream of the plurality of delivery branches of the dispensing unit (2) and in fluid communication with the supply duct, the compensation unit defining a variable internal compensation volume from a maximum volume configuration to a minimum volume configuration when the metering unit (3) is in the discharge configuration and from the minimum volume configuration to the maximum volume configuration when the metering unit (3) is in the filling configuration.

8. The device according to claim 7, comprising a compensation actuator connected to the compensation unit for varying the compensation volume between the maximum volume configuration and the minimum volume configuration.

9. The device according to any one of claims 1 to 8, wherein the control unit is programmed to derive an imbalance parameter and drive one or more of the actuators according to the imbalance parameter, the imbalance parameter representing an imbalance between the flows of plastic in the plurality of delivery branches.

10. The device according to any one of claims 1 to 9, wherein the control unit is connected to the plurality of outlet valves (203) and controls them synchronously.

11. The device comprises an extruder connected to the supply duct for supplying the continuous flow of pressurized molten plastic to the supply duct, the control unit being programmed to control the extruder according to one or more of the following parameters, namely, - A check parameter representing the difference between the volume or mass of the dose delivered from the delivery branch and the reference value of the volume or mass of the dose. - A flow rate parameter representing the flow rate of the plastic flowing in the supply duct. - The device according to any one of claims 1 to 10, which is programmed to control the extruder according to one or more of the following parameters: an imbalance parameter representing the imbalance between the plastic flow rates in the plurality of delivery branches.

12. An extruder and a positive displacement pump connected to the supply duct for supplying the continuous flow of pressurized molten plastic to the supply duct, which is arranged downstream of the extruder, and the control unit is programmed to control the positive displacement pump according to one or more of the following parameters, namely: - A check parameter representing the difference between the volume or mass of one dose delivered from the delivery branch and the reference value of the volume or mass of the dose. - A flow rate parameter representing the flow rate of the plastic flowing in the supply duct. - The device according to any one of claims 1 to 11, which is programmed to control the positive displacement pump according to one or more of the following parameters: an imbalance parameter representing the imbalance between the plastic flow rates in the plurality of delivery branches.

13. A method for manufacturing an object from a plastic material in a continuous cycle, comprising: - Providing a distribution unit (2) including a plurality of delivery branches (203) each having an outlet (205) and a supply duct (201) having an inlet (202) communicating with the plurality of delivery branches (203) via a distribution zone (204), the distribution unit (2) defining an internal volume between the inlet (202) and the outlet (205). - Receiving a flow of molten plastic at the inlet (202) of the supply duct (201). - Distributing the flow of plastic to the plurality of delivery branches (203) via the distribution zone (204). - Providing a metering unit, the metering unit comprising: An outlet valve system having a plurality of outlet valves (302), each outlet valve being arranged in a corresponding delivery branch (203). A plurality of partition elements, each of the plurality of partition elements being arranged in a corresponding delivery branch upstream of the corresponding outlet valve, each of the plurality of partition elements being movable between an upper limit position (X1) and a lower limit position (X2) in order to change the internal volume of the distribution unit (2), a plurality of partition elements; A group of actuators, each actuator of the group of actuators being connected to a corresponding partition element of the plurality of partition elements and moving it between the upper limit position (X1) and the lower limit position (X2), a group of actuators; and, - Through a control unit (5), Closing the outlet valve system (302), blocking the flow of plastic delivered from the distribution unit, and controlling one or more actuators of the group of actuators to move the corresponding partition element from the lower limit position to the upper limit position; Opening the outlet valve system (302) to allow plastic to be discharged from the internal volume of the distribution unit (2), controlling one or more actuators of the group of actuators to move the corresponding partition element from the upper limit position to the lower limit position so as to form a plurality of doses of plastic; - Supplying the dose to a plurality of sheets (402) of a plurality of female elements (401) arranged in the plurality of delivery branches (203); - Compressing the dose between the plurality of female elements (401) and corresponding male elements (403) to form a plurality of objects of plastic material. A method comprising.

14. According to one or more of the following parameters, namely, - A check parameter representing the difference between the volume or mass of a single dose delivered from the delivery branch and a reference value of the volume or mass of the dose, - A flow rate parameter representing the flow rate of the plastic flowing in the supply duct, - An imbalance parameter representing the imbalance between the plastic flow rates in the plurality of delivery branches, the method according to claim 13, comprising moving the partition element by the group of actuators according to one or more of.

15. - moving each of the plurality of female elements (401) along a longitudinal movement axis (X) between a spaced position where it does not interfere with the corresponding male element of the plurality of male elements (403) and a proximity position where it closes the forming cavity with respect to the corresponding male element (403); - compressing the dose between each female element (401) and the corresponding male element (403) when the forming cavity is in the closed position; - performing an adaptive movement along the longitudinal movement axis (X) via each male element (403) connected to an elastic element (404); - deriving the check parameter in response to the adaptive movement through the control unit (5); The method according to claim 14, comprising the steps of:

16. The method according to any one of claims 1 to 15, comprising the step of synchronously controlling the outlet valve through the control unit.

17. - supplying a continuous flow of pressurized molten plastic through an extruder or a positive displacement pump disposed downstream of the extruder and connected to the supply duct to the supply duct; - according to one or more of the following parameters, namely, - a check parameter representing the difference between the volume or mass of a single dose delivered from the delivery branch and a reference value of the volume or mass of the dose; - a flow rate parameter representing the flow rate of the plastic flowing in the supply duct; - controlling the extruder or the positive displacement pump through the control unit according to one or more of the imbalance parameters representing the imbalance between the plastic flow rates in the plurality of delivery branches; The method according to any one of claims 13 to 16, comprising the steps of:

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