DEVICE AND METHOD FOR MANUFACTURING CONTAINERS FROM PREFORMS

Description

[0001] The invention relates to a device and a method for manufacturing containers from thermally conditioned preforms, in particular from a thermoplastic material, preferably PET. The invention further relates to a stretch blow molding machine. The production of containers by blow molding from preforms made of a thermoplastic material, for example from PET (polyethylene terephthalate) preforms, is known, wherein the preforms are fed to different processing stations within a blow molding machine. Typically, a blow molding machine has a heating device for tempering or thermally conditioning the preforms and a blow molding unit with at least one blowing station, in which the previously temperature-conditioned preform is expanded into a container.Expansion is achieved using a pressurized gas (compressed air) as the pressure medium, which is introduced into the preform to be expanded under pressure. The process engineering procedure for such expansion of the preform is explained in DE 43 40 291 A1. The basic structure of a blow molding station is described in DE 42 12 583 A1. Methods for temperature control of the preforms are explained, for example, in DE 23 52 926 A1. Temperature control or thermal conditioning means that the preform is heated to a temperature suitable for blow molding and, if necessary, a temperature profile is applied to the preform in the longitudinal and / or circumferential and / or radial direction. Blow molding of containers from preforms using an additional stretching bar is also known.

[0002] In a typical downstream processing method, the containers produced by blow molding are fed to a subsequent filling unit and filled with the intended product or fill material. This involves using separate blow molding machines and filling machines. It is also known to combine the separate blow molding machines and filling machines into a single machine unit, i.e., a combined blow molding and filling unit, whereby the blow molding and filling processes still take place on separate machine components and sequentially. Before filling the containers with the intended product or fill material, a coating can also be applied to the inside of the containers using a coating unit. After filling, the containers can be labeled in a labeling station.

[0003] In the forming process using a device for manufacturing containers from thermally conditioned preforms, various pressure stages are typically applied, for example, first a pre-blow pressure, then an intermediate pressure, and then a main blow pressure. Further pressure stages may also be provided.

[0004] Typically, the compressed air is guided outside the die, particularly around the outer circumference of the die and parallel to it, towards the preform. It is also known to use a hollow die, as described, for example, in DE 28 14 952 A1. Here, the pressurized gas is connected via an end of the tubular die opposite the die's apex. Supplying pressurized gas via the end of a hollow die is also described in DE 34 08 740 C2. Furthermore, EP 1 660 302 B1 discloses a method for blow molding containers in which pressurized gas is introduced into the container through the die. In this method, the pressurized gas is introduced laterally from a pressure chamber into an interior space of the die and then guided within the die to outlet openings.The pressurized gas is introduced into the interior of the bar through a plurality of openings, the openings being distributed both along a circumference and in the direction of a longitudinal axis of the horizontal bar.

[0005] From US 2013 / 153809 A1, a valve for a machine for inflating containers is known, comprising a hollow valve body with an axis, a cover, at least two sleeves movable along the axis in the chamber, at least one inlet and one outlet, and control means configured to move the sleeves in the chamber. The sleeves are assembled one inside the other and form a channel for the passage of an inflation gas.

[0006] From EP 2 669 070 A1 a hollow body manufacturing machine is known, comprising at least one mold within which hollow bodies can be produced by applying a pressurized medium, at least one valve unit which is operatively connected to the mold in such a way that medium can be supplied to or discharged from a material to be formed in the mold by at least two valves, wherein the valves have at least one opening in the direction of the hollow body to be formed and at least one opening in the direction of a pressure accumulator.

[0007] From EP 2 176 053 B2, a device for blow forming of containers is known, which has at least one blowing station with a blow mold, and in which a flow path for a blowing gas for blow forming the containers extends through a connection element which has a valve carrier which holds at least one valve, wherein the valve surrounds a main channel of the valve carrier in a ring-like manner, wherein each valve arranged in a module housing forms a valve module, and wherein at least two valve modules are arranged one above the other in a longitudinal direction of the valve body.

[0008] From WO 2011 / 154326 A1, a proportional stretch blow molding system is known, comprising a cylinder and a piston that is movable within the cylinder and divides the cylinder into a first chamber and a second chamber. The proportional stretch blow molding system also includes a proportional blow molding valve. The proportional blow molding valve comprises a first opening configured to receive a pressurized gas and a second opening that is in fluid communication with the cylinder and selectively in fluid communication with the first opening.

[0009] From US 11 235 505 B2, a method for manufacturing a liquid container is known, comprising: a liquid blow molding step of forming a preform into a liquid container; and a headspace formation step of forming a headspace by ejecting a liquid from the liquid container through an ejection port in a state in which a liquid supply path is closed, wherein the ejection is achieved by suction through a liquid suction source.

[0010] One problem with known methods and devices for manufacturing containers from thermally conditioned preforms is that a large volume of compressed air must be supplied, resulting in high energy consumption for applying the pressure stages—and thus for the entire forming process. This relatively high energy requirement is therefore due, among other things, to the high compressed air consumption during the forming process.

[0011] The invention is therefore based on the objective of providing an improved solution that addresses the aforementioned problems. In particular, it is an objective of the invention to provide a solution by means of which more energy-efficient production of containers from preforms is enabled, preferably while simultaneously increasing the production speed.

[0012] According to a first aspect of the invention, the problem is solved by a device according to claim 1. This device comprises a device for producing containers from thermally conditioned preforms, in particular from a thermoplastic material, preferably PET, the device comprising a blow nozzle for blowing compressed air into a preform for forming the preform into a container, the blow nozzle having a blow nozzle opening, a stretching rod for stretching the preform which extends along a longitudinal axis through the blow nozzle and at least partially within the blow nozzle, and which is axially movable relative to the blow nozzle opening for stretching the preform, and a valve block with several blow air valves which are axially movable along the longitudinal axis and within the valve block and which are at least partially annular in shape.wherein at least two of the air valves surround the pull-up bar at least sectionally in an annular manner, wherein the multiple air valves comprise a first air valve and a second air valve, wherein the second air valve is arranged adjacent to the first air valve, wherein a sealing surface is arranged between the first air valve and the second air valve on at least one of these two air valves, which, when these two air valves are in contact, blocks a fluid flow path for a fluid flow, in particular for a gas flow, which runs between these two air valves and to the blow nozzle opening, by means of a sealing effect.

[0013] According to the invention, the first blow-air valve is arranged at least partially inside the second blow-air valve in a radial direction that runs orthogonally to the longitudinal axis.

[0014] It is therefore proposed that the first and second air valves surround each other at least partially in a ring-like fashion. In particular, it is proposed that the second air valve surrounds the first air valve at least partially in a ring-like fashion. The first air valve is thus located at least partially within the second air valve.

[0015] By means of this arrangement of the blow-air valves one inside the other, it can be achieved in a particularly advantageous way that the distance between the blow-air valves and the preform is significantly reduced, since the blow-air valves can in this way be arranged essentially at the same height and close to the preform.

[0016] One advantage of such a device is that the dead space volume can be significantly reduced compared to known devices. This allows for more efficient use of compressed air and enables more energy-efficient container production. It is even possible to achieve a negative dead space volume.

[0017] Another advantage is that pressure build-up and release are faster because the volume in which pressure is built up is smaller overall than with conventional devices. This allows the overall process to be accelerated and production output increased.

[0018] Preferably, the first and second air vents are arranged parallel to each other, at least partially, with respect to the longitudinal axis, i.e., at the same height along the longitudinal axis. This allows both the first and second air vents to be advantageously positioned directly above the opening of the preform, thereby reducing the dead space volume. It is also possible for the first and second air vents to be arranged at the same height with respect to the longitudinal axis only in one section and not in the same section.

[0019] The blow nozzle is preferably designed to blow compressed air into a preform for forming the preform into a container and / or to discharge compressed air from a container formed from the preform. Thus, compressed air can be blown into the preform via the blow nozzle opening to form the preform into a container, and / or compressed air can be discharged from a formed container to depressurize it and / or to recover compressed air no longer required for the forming process.

[0020] The blow nozzle preferably has a blow nozzle seal arranged at the blow nozzle opening for sealing the blow nozzle opening against a preform. Such a blow nozzle seal ensures a fluid-tight seal between the blow nozzle opening and the preform, allowing compressed air to flow from the blow nozzle opening into the preform and / or from the preform to the blow nozzle opening without any loss of compressed air to the environment.

[0021] The device preferably comprises a blow mold, including two mold halves, wherein the blow mold is adjustable between a closed and an open state, and wherein, in the closed state, the blow mold has a forming cavity for forming the preform into a container. The blow mold may optionally also have a bottom section, which is preferably movable and can form a forming cavity together with the blow mold halves.

[0022] The pull-up bar extends along the longitudinal axis and, in particular, through the blow nozzle. The pull-up bar can have a circular cross-section and be rotationally symmetrical about the longitudinal axis. The pull-up bar preferably extends within the valve block and preferably through the blow-air valves, especially within the blow-air valves themselves.

[0023] The stretching rod can preferably be moved relative to the blow nozzle along its longitudinal axis and, in particular, towards the preform to stretch it. The stretching rod can be moved along its longitudinal axis along a stretching path. A stretching path is defined as the path of the stretching rod over which it exerts a stretching force and / or a guiding force on the preform. This is equivalent to the path of the stretching rod, which begins when the tip of the rod first contacts the base of the preform and ends when it reaches a final position, where, in this final position, the base of the fully stretched preform is typically clamped between the tip of the stretching rod and the surrounding mold. The stretching path thus describes the distance the stretching rod travels when stretching and / or guiding the preform, starting with the initial contact between the tip of the stretching rod and the preform.

[0024] The multiple compressed air valves are axially movable along the longitudinal axis and within the valve block. The multiple compressed air valves are preferably annular in shape and preferably arranged at least partially within one another. In particular, the compressed air valves are arranged in a ring-like configuration surrounding each other. Such an annular configuration is particularly advantageous for the manufacturability of the compressed air valves and the components interacting with them. However, the multiple compressed air valves can also have a cross-section that does not form a complete ring, but only a portion of one. The multiple compressed air valves can thus also extend along a circular arc with a central angle of less than 360°, so that, for example, compressed air valves can also extend along a circle.

[0025] The second blow-off valve is located adjacent to the first blow-off valve. Preferably, no further blow-off valve is located between the first and second blow-off valves. However, additional blow-off valves may be present. For example, a blow-off valve may be located adjacent to the second blow-off valve, and in particular, may be arranged in a ring-like configuration surrounding the second blow-off valve.

[0026] A sealing surface is arranged on at least one of the two air blast valves between the first and second air blast valves. This sealing surface can be located on the first air blast valve and / or on the second air blast valve. The sealing surface forms a valve seat, preferably allowing one of the two air blast valves to guide the other, thus creating a seal between the two valves. When these two air blast valves are in contact, the fluid flow path between them, which runs towards the nozzle opening, is blocked by this seal.

[0027] The terms fluid flow path and flow path are used synonymously here and in the following. A flow path, therefore, preferably refers to a gas flow path, particularly for a compressed air flow.

[0028] The sealing surface is preferably formed radially inside the second air valve and / or radially outside the first air valve. This allows the first and second air valves to be arranged particularly advantageously within each other and essentially at the same height. However, it is also possible for the sealing surface to be located at a different position on the first and / or second air valve.

[0029] Preferably, each compressed air valve controls a flow path into the preform. When the compressed air valves are in contact with each other, the respective flow path controlled by each valve is blocked. When the compressed air valves are moved so that they are not in contact with each other, the flow path is opened, allowing compressed air to flow through it.

[0030] It is particularly preferred that the multiple compressed air valves include a third compressed air valve arranged adjacent to the second compressed air valve. Preferably, the second and third compressed air valves are arranged at least partially within one another in the radial direction. This arrangement of the third compressed air valve makes it particularly advantageous to significantly reduce the distance between each of the first, second, and third compressed air valves and the preform, since these three compressed air valves can thus be arranged essentially at the same height and close to the preform. This allows the dead space volume to be significantly reduced, and thus the compressed air to be used more efficiently.

[0031] Preferably, the second and third compressed air valves surround each other at least partially in an annular arrangement. Preferably, the third compressed air valve surrounds the second compressed air valve at least partially in an annular arrangement. The second compressed air valve is thus arranged at least partially within the third compressed air valve. This arrangement of the second and third compressed air valves makes it particularly advantageous to significantly reduce the distance between the second compressed air valve and the preform, as well as between the third compressed air valve and the preform, since these compressed air valves can be arranged essentially at the same height and close to the preform. This allows the dead space volume to be significantly reduced, even with three compressed air valves surrounding each other at least partially in an annular arrangement, and thus the compressed air to be used more efficiently.

[0032] Preferably, the second and third air vents are arranged parallel to each other, at least partially, with respect to the longitudinal axis, i.e., at the same height along the longitudinal axis. Preferably, the first, second, and third air vents are arranged parallel to each other, at least partially, with respect to the longitudinal axis, i.e., at the same height along the longitudinal axis. This allows both the second and third air vents to be arranged advantageously directly above the opening of the preform, thereby reducing the dead space volume. It is also possible for the second and third air vents to be arranged at the same height with respect to the longitudinal axis only in one section and not in the same height in another section.

[0033] The multiple air vents can also include more than three air vents, for example a fourth and optionally a fifth air vent. These air vents are then preferably arranged radially, at least partially within one another, and surround each other at least partially in a ring shape.

[0034] It is particularly preferred that a horizontal bar seal is arranged between the horizontal bar and the first air valve.

[0035] The pull-rod seal is preferably designed as a sliding seal, allowing the pull-rod to move along its longitudinal axis without moving the seal itself. The pull-rod seal is preferably a dynamic seal designed to permit axial movement of the pull-rod along its longitudinal axis while providing a seal between the pull-rod and the radially inner circumference of the first blow-off valve.

[0036] It is particularly preferred that the pull-rod seal is arranged on the first air valve and connected to it, preferably by force-fit and / or positive locking. Preferably, a sealing recess is provided on the first air valve in which the pull-rod seal can be inserted, so that the pull-rod seal is positively connected to the first air valve via this recess. Such a sealing recess can, for example, comprise one or more steps and / or be groove-shaped along the inner circumference of the first air valve.

[0037] According to the invention, the blow-air valves have valve seats, wherein the valve seats are arranged at the nozzle-opening-side end of the blow-air valves and are arranged at an angle relative to the longitudinal axis. An advantage of such an arrangement of the valve seats is that the sealing surfaces can be positioned close to the preform, thereby further reducing the dead space volume. It is also possible for the valve seats to be arranged without an angle.

[0038] The valve seats of the blow-off valves are preferably designed as inclined surfaces, wherein the inclined surface is preferably inclined to the longitudinal axis, in particular not parallel and not orthogonal to the longitudinal axis, for example at an angle of 45° relative to the longitudinal axis. An advantage of such an inclined surface is that the valve seats, in the closed state, can be arranged at approximately the same height and thus particularly close to the preform, which further reduces the dead space volume.

[0039] According to the invention, the valve seats are arranged directly adjacent to the blow nozzle opening, in particular with a distance between the annular edge of the valve seats closest to the blow nozzle opening and the blow nozzle opening of less than 120 mm, preferably less than 60 mm, particularly preferably less than 20 mm.

[0040] An arrangement of the valve seats immediately adjacent to the blow nozzle opening shall in particular be understood to mean a small distance between the annular edge of the valve seats closest to the blow nozzle opening and the blow nozzle opening, wherein the small distance is less than 120 mm, preferably less than 60 mm, particularly preferably less than 20 mm.

[0041] One advantage of such an arrangement, in which the valve seats are located directly adjacent to the blow nozzle opening, is that there are no large volumes between the blow air valve seats and the preform that need to be filled with compressed air when pressurized. This allows for a very small dead space volume, or even no dead space volume at all, or a negative dead space volume.

[0042] It is particularly preferred that the blow-off valves are designed such that the projected area at least partially overlaps adjacent blow-off valves when viewed along the longitudinal axis. Preferably, adjacent valves have overlapping areas when projected or viewed along the longitudinal axis.

[0043] Adjacent air valves are understood to be, in particular, air valves that are arranged one inside the other, with no air valve located between them. For example, the first and second air valves are adjacent air valves. Similarly, the second and third air valves are adjacent air valves. The first and third air valves are therefore not adjacent air valves.

[0044] Preferably, adjacent air vents overlap when projected along the longitudinal axis. This makes it particularly advantageous to move an air vent along the longitudinal axis only until it touches an adjacent air vent, with the exception of the first air vent, since no further air vent is located within the first air vent.

[0045] According to the invention, in a position where the blow-off valves are closed, the valve seats are arranged at essentially the same height with respect to the longitudinal axis. In this closed position, the blow-off valves block the respective flow paths they control. In this position, the blow-off valves are preferably arranged as far as possible with respect to the longitudinal axis in the direction of the blow-off nozzle opening, thereby advantageously reducing the dead space volume.

[0046] It is particularly preferred that the device includes control means by which the multiple blow-air valves can each be adjusted axially along the longitudinal axis. Preferably, the device includes control air connections to which control air lines can be connected or are connected, with control air being supplied to the control means via the control air lines in order to adjust the blow-air valves axially along the longitudinal axis. The use of control air is particularly advantageous because a pneumatic system and compressed air are also provided for blow molding. However, it is also possible for the control means to operate in another way, i.e., without control air, for example, electromagnetically.

[0047] Preferably, each of the compressed air valves is pneumatically controllable. However, non-pneumatic control of the compressed air valves is also conceivable.

[0048] It is particularly preferred that the device has several lines, each controlled by one of the blow-air valves. The device comprises a pre-blow pressure line for providing a pre-blow pressure, and / or a main blow-air pressure line for providing a main blow-air pressure, and / or an intermediate pressure line for providing an intermediate pressure, and / or a vent line for venting the area of ​​the blow-air nozzle opening, and / or an airbag line for providing an air pressure return system. The multiple lines preferably have different pressures. The pre-blow pressure is preferably in the range of 5 bar to 25 bar. The intermediate pressure is preferably in the range of 10 bar to 35 bar. The main blow-air pressure is preferably in the range of 20 bar to 40 bar.

[0049] The multiple lines are preferably the pre-inflation pressure line, and / or the main inflation pressure line, and / or the intermediate pressure line, and / or the vent line and / or the airbag line.

[0050] It is particularly preferred that the blow nozzle is adjustable in the axial direction along the longitudinal axis between a blowing position, in which the blow nozzle opening seals against a preform and / or a blow mold holding the preform, and a rest position, in which the blow nozzle opening is spaced apart from a preform. Preferably, the blow nozzle can be held in the blowing position by means of a toggle lever.

[0051] It is particularly preferred that the device comprises a horizontal bar flow path for guiding compressed air through the horizontal bar, wherein the horizontal bar flow path extends from a first horizontal bar opening through the compressed air channel to a second horizontal bar opening.

[0052] This allows for a particularly advantageous reduction in the number of air valves required outside the horizontal bar compared to conventional devices, as a controllable valve is located inside the bar. This results in a smaller installation space being needed for the valve block containing the air valves surrounding the horizontal bar.

[0053] Furthermore, the air valves located outside the horizontal bar can be arranged inside each other in a simpler way, in particular in a ring-shaped arrangement, since the number of air valves outside the horizontal bar is reduced.

[0054] Preferably, a controllable compressed air channel valve is arranged inside the horizontal bar, which can be adjusted between an open position, in which the compressed air channel valve opens the flow path of the horizontal bar, and a closed position, in which the compressed air channel valve closes the flow path of the horizontal bar. Therefore, preferably a controllable compressed air channel valve is arranged inside the horizontal bar.

[0055] This makes it particularly advantageous to further reduce the dead space volume (with a constant total number of flow paths and valves), as one less blow-air valve is needed in the valve block.

[0056] A further advantage is that rinsing, in particular with gas, preferably air, is possible after the forming process by introducing gas through the drawing bar into the formed container and / or cooling of the container from the inside, i.e. within the formed container, in particular with gas, preferably air, is possible after the forming process by introducing gas through the drawing bar into the formed container.

[0057] Preferably, a valve is arranged within the pull-up bar that is adjustable between the open and closed positions, allowing it to open and close the airflow path. When the airflow valve is in the closed position, it closes the airflow path, preventing compressed air from passing through the pull-up bar. When the airflow valve is in the open position, it opens the airflow path, allowing compressed air to pass through the pull-up bar.

[0058] Preferably, the compressed air channel valve is not designed as a pure check valve. In particular, the compressed air channel valve can be designed like a check valve, but preferably one that is actively controllable independently of the application of compressed air.

[0059] The horizontal bar preferably has a compressed air channel running inside it. The flow path is preferably designed such that compressed air can be guided through the horizontal bar. The flow path extends from the first opening of the horizontal bar, through the compressed air channel, and to the second opening of the horizontal bar.

[0060] It is particularly preferred that the stretching rod has a stretching rod end section with a stretching rod tip, wherein the compressed air channel inside the stretching rod extends to the stretching rod end section, preferably to the stretching rod tip, wherein the second stretching rod opening is arranged in the region of the stretching rod end section, which preferably comprises several outlet openings formed laterally on the stretching rod. This allows a relatively homogeneously distributed injection of compressed air into the preform, so that the container can be formed accordingly homogeneously during the blow molding process.

[0061] The compressed air channel valve is preferably located in the area of ​​the end section of the pull-up bar, and preferably near the tip of the pull-up bar.

[0062] A horizontal bar end section is understood to be, in particular, a section of the horizontal bar that includes the bar tip and, additionally, a section of the horizontal bar that adjoins the bar tip. A bar tip is understood to be, in particular, the part of the horizontal bar that is located at the end of the horizontal bar that is in contact with the preform when the preform is stretched. The bar tip can, in particular, be designed as a rounded tip at the end of the horizontal bar.

[0063] It is particularly preferred that the device comprises a valve plunger which is arranged at least partially within the pull-up bar, and in particular at least partially within the compressed air channel, wherein the valve plunger is arranged and designed to adjust the compressed air channel valve between the open position and the closed position, preferably by a purely axial movement along the longitudinal axis, wherein the valve plunger preferably comprises or consists of fiber-reinforced plastic, in particular carbon fiber-reinforced plastic.

[0064] The second opening of the pull-up bar preferably comprises several outlet openings, which are arranged particularly in the region of the pull-up bar end section. The outlet openings are preferably designed as bores. The outlet openings can, for example, be oriented towards the bottom section, for instance to promote cooling of the bottom of the container. However, the outlet openings can also be oriented perpendicular to the longitudinal axis. It is also possible for some outlet openings to be non-orthogonal and some outlet openings to be oriented perpendicular to the longitudinal axis.

[0065] It is preferred that the outlet openings are arranged symmetrically around the longitudinal axis. Preferably, the outlet openings are arranged such that they are not obscured by the preform.

[0066] It is preferred that the outlet openings are arranged within the preform in a position of the stretching movement in which the stretching bar is inserted furthest into the preform.

[0067] The compressed air channel valve is preferably spaced at most 50 mm, particularly preferably at most 30 mm, and especially at most 15 mm, away from the tip of the horizontal bar.

[0068] It is particularly preferred that the compressed air channel valve has a valve body and a valve seat, wherein the valve body and the valve seat are designed and arranged to close the flow path in the closed position of the compressed air channel valve and to release the flow path in the open position of the compressed air channel valve, preferably by a purely axial movement along the longitudinal axis.

[0069] Preferably the valve body is connected to the valve tappet and / or the valve body is rotationally symmetrical with respect to the longitudinal axis.

[0070] Preferably, the adjustment of the compressed air channel valve between the closed position and the open position is effected by moving the valve body relative to the valve seat, in particular along the longitudinal axis.

[0071] Preferably, the valve plunger extends centrally within the, preferably tubular, extension rod and along its longitudinal axis. The valve plunger is preferably axially movable along its longitudinal extent and along its longitudinal axis.

[0072] It is particularly preferred that the second pull-up bar opening is arranged in the area of ​​the pull-up bar end section, preferably near the pull-up bar tip, wherein a compressed air throttle is arranged in the pull-up bar flow path between the compressed air channel valve and the second pull-up bar opening, which is preferably arranged in the area of ​​the pull-up bar end section, in particular near the pull-up bar tip.

[0073] Preferably, the second pull-rod opening, which may include several outlet openings, is arranged behind the compressed air channel valve when compressed air is introduced through the pull-rod into the preform, with respect to the flow direction through the pull-rod flow path.

[0074] It is preferred that the first opening of the pull rod, when compressed air is introduced through the pull rod into the preform, is arranged upstream of the compressed air channel valve with respect to the flow direction. Preferably, therefore, when compressed air is introduced into the preform, the compressed air is guided from the first opening of the pull rod along the pull rod flow path, through the compressed air channel valve, to the second opening of the pull rod, and from there into the preform.

[0075] It is particularly preferred that the compressed air throttle comprises a bore which preferably extends along the longitudinal axis, wherein the bore of the compressed air throttle preferably has a diameter of at least 2 mm, more preferably at least 3 mm, and wherein the bore of the compressed air throttle preferably has a diameter of at most 6 mm, more preferably at most 5 mm. It is particularly preferred that the bore of the compressed air throttle has a diameter of 4 mm.

[0076] Preferably, the flow cross-section of the bore of the compressed air throttle is smaller than at least one section of the flow cross-section of the compressed air duct in the area upstream of the compressed air duct valve.

[0077] By means of the compressed air throttle, the volume flow of the compressed air before exiting the outlet openings can be regulated in a particularly advantageous way by reducing the cross-sectional area of ​​the line, so that an optimal volume flow for the forming process flows from the outlet openings into the preform.

[0078] According to a further aspect of the invention, the aforementioned problem is solved by a stretch blow molding machine comprising a blowing wheel with several blowing stations arranged circumferentially spaced on it, each of the blowing stations comprising a device as described herein. Preferably, the blowing stations are designed and arranged to rotate cyclically on a circular path, in particular a circular path, and preferably to perform a forming operation on each rotation.

[0079] According to a further aspect of the invention, the aforementioned problem is solved by a method for producing containers from thermally conditioned preforms, which in particular consist of a thermoplastic material, especially PET, the method comprising the steps of: providing a device or a stretch blow molding machine as described herein, arranging the valve block in a position in which the blow nozzle opening is in sealing contact with a preform and / or with a blow mold holding the preform, moving the first blow air valve and / or the second blow air valve along the longitudinal axis to release the fluid flow path that runs between the two blow air valves and to the blow nozzle opening, and preferably applying pressure to the preform.

[0080] Preferably, a multi-stage forming process with several pressure stages is used. First, a low pre-blow pressure, also called P1 pressure, is preferably applied. It is particularly preferred if the pre-blow pressure is applied through the drawing bar via the flow path. Preferably, an intermediate pressure, also called PB pressure, is then applied, which can be higher than the pre-blow pressure. The intermediate pressure can be applied, for example, by opening the first blow-off valve. Preferably, a main blow-off pressure, also called P2 pressure, is then applied, which can be higher than the intermediate pressure. The intermediate pressure can be applied, for example, by opening the second blow-off valve. The pre-blow pressure, or P1 pressure, is preferably in the range of 5 bar to 25 bar. The intermediate pressure, or PB pressure, is preferably in the range of 10 bar to 35 bar. The main blow-off pressure, or P2 pressure, is preferably in the range of 10 bar to 35 bar.The P2 pressure is preferably in the range of 20 bar to 40 bar.

[0081] Additional pressure stages can be applied before, after, or between these pressures. It is also conceivable to work with only a pre-blow pressure and a main blow pressure.

[0082] For the advantages, design variants and design details of the various aspects of the solutions described here and their respective possible further developments, reference is also made to the description of the corresponding features, details and advantages of the other aspects and their further developments.

[0083] Preferred embodiments are explained by way of example with reference to the accompanying figures. The drawings are not necessarily to scale. In the figures, identical or essentially functionally equivalent or similar elements are designated with the same reference numerals. They show: Fig. 1: a highly schematic representation of a stretch blow molding machine; Fig. 2: a schematic representation of a device for producing containers from thermally conditioned preforms; Fig. 3: a schematic representation of a method for producing containers from thermally conditioned preforms.

[0084] Fig. 1 Figure 1 shows a highly schematic representation of a stretch blow molding machine 100. Containers 90 can be produced from preforms 80 using the stretch blow molding machine 100. The illustration shows the preferred embodiment of such a stretch blow molding machine as a rotary machine with a rotating blow wheel 120, which can also be referred to as a working wheel and carries several forming stations 116. In the area of ​​the forming stations 116, preforms 80 are transformed into containers 90 by biaxial expansion.

[0085] In a typical configuration, a stretch blow molding machine 100 for producing a container 90 includes a temperature control device 126 for temperature control or thermal conditioning of the preforms 80. As shown here, the temperature control device 126 can be located upstream of the blow wheel 120, so that the preforms 80 can be heated before reaching the forming stations 116. Preforms 80, which can also be referred to as preforms, can be continuously fed to the temperature control device 126 from a feeding device 122 using a transfer wheel 124. Within the temperature control device 126, the preforms 80 are transported along a heating section and thermally conditioned.

[0086] The temperature control device 126 is, for example, equipped with heating elements 128 arranged along a transport device 130 to form the heating section. The transport device 130 can be, for example, a circulating conveyor chain with transport elements designed as transport mandrels for holding the preforms 80. Suitable heating elements 128 include, for example, infrared emitters (IR emitters), light-emitting diodes (LEDs), or near-infrared emitters (NIR emitters). Such temperature control devices are known in various forms in the prior art.

[0087] After sufficient temperature control, also called thermal conditioning, the preforms 80 are transferred from a transfer wheel 132 to a rotatably arranged blow wheel 120, i.e., driven around a vertical machine axis, or to forming stations 116, which are arranged circumferentially around the blow wheel 120. The blow wheel 120 is equipped with a plurality, i.e., at least two, such forming stations 116. For the biaxial expansion of the preforms 80 in the area of ​​the forming stations 116, the preforms 80 are pressurized with a gas. The preforms 80 are thereby filled with a blowing gas in the area of ​​the forming stations 116, which serves as the pressure medium for the forming process.

[0088] The blow mold 120 rotates continuously at a desired speed during production. During one rotation, a preform 80 is inserted into a forming station 116, the preform 80 expands into a container 90, and the container 90 is removed from the forming station 116.

[0089] The forming stations 116 have a stretching bar that can be inserted into the preform 80 to support axial stretching and guidance. During one revolution of the blow wheel 120, the preforms 80 are also stretched simultaneously.

[0090] After the containers 90 have been formed in the area of ​​the blowing wheel 120, the containers 80 are removed from the blowing wheel 120 by a removal wheel 134, transported further and fed to an output section 136.

[0091] Various thermoplastic materials can be used for the preforms 80. Examples include polyethylene terephthalate (PET), polyethylene (PE), polyethylene naphthalate (PEN), or polypropylene (PP). The dimensions and weight of the preforms 80 are adapted to the size, weight, and / or design of the containers 90 to be manufactured.

[0092] Fig. 2 shows a schematic sectional view of a device for manufacturing containers from thermally conditioned preforms. The in Fig. 2 The device shown can in particular be part of a Fig. 1 The converter station shown is 116, or one in Fig. 1 The forming station shown is 116.

[0093] The device is designed for producing containers from thermally conditioned preforms, in particular from a thermoplastic material, preferably PET. The device comprises a blow nozzle 1 for blowing compressed air into a preform 80 to form the preform 80 into a container. The blow nozzle 1 has a blow nozzle opening 2. A stretching rod 50 is provided for stretching the preform 80. The stretching rod 50 extends along a longitudinal axis A through and within the blow nozzle 1. The stretching rod 50 is axially movable relative to the blow nozzle opening 2 for stretching the preform 80.

[0094] The blow nozzle 1 is located in the axial direction along the longitudinal axis A between the in Fig. 2The nozzle opening 2 is adjustable between the illustrated blowing position, in which it is in a sealing position against a preform 80, and a rest position (not shown), in which the nozzle opening 2 is spaced apart from the preform 80. The preform 80 has a thread 81 in the area of ​​its opening, onto which a cover with a corresponding thread can be screwed.

[0095] The blow nozzle 1 has a blow nozzle seal 30 arranged at the blow nozzle opening 2 for sealing the blow nozzle opening 2 against a preform 80. The blow nozzle seal 30 is arranged at an end section 19 of the blow nozzle 1 facing the preform 80. By means of such a blow nozzle seal 30, a fluid-tight seal between the blow nozzle opening 2 and the preform 80 can be achieved, so that compressed air can flow from the blow nozzle opening 2 into the preform 80 and / or from the preform 80 to the blow nozzle opening 2 without any loss of compressed air to the environment.

[0096] The preform 80 is arranged in a blow mold 70. The blow mold 70 comprises two blow mold halves 71, 72. The blow mold 70 is adjustable between a closed state and an open state. Fig. 2The closed position is shown, in which the blow mold halves form a forming cavity for forming the preform 80 into a container. In addition to the blow mold halves 71, 72, the blow mold may also have a bottom part (not shown).

[0097] A valve block 10 has several air valves 21, 22, 23 that are axially movable along the longitudinal axis A and within the valve block 10. The multiple air valves 21, 22, 23 are annular and rotationally symmetrical about the longitudinal axis A. The three air valves 21, 22, 23 shown here surround the pull-up bar 50 in an annular fashion. The multiple air valves 21, 22, 23 comprise a first air valve 21, a second air valve 22, and a third air valve 23. The second air valve 22 is arranged adjacent to the first air valve 21, and the third air valve 23 is arranged adjacent to the second air valve 22.

[0098] Valve block 10 has seals 10a, 10b, which are designed as dynamic seals and provide a sealing effect when the first compressed air valve 21 moves along its longitudinal axis A. The first compressed air valve 21 has a dynamic seal 21a, which can provide a sealing effect when the first compressed air valve 21 moves along its longitudinal axis A. Valve block 10 also has seals 10c, 10d, which are designed as dynamic seals and provide a sealing effect when the second compressed air valve 22 moves along its longitudinal axis A. The second compressed air valve 22 has a dynamic seal 22a, which can provide a sealing effect when the second compressed air valve 22 moves along its longitudinal axis A.The valve block 10 further comprises seals 10e, 10f, which are designed as dynamic seals and provide a sealing effect when the third blow-air valve 23 moves along the longitudinal axis A. The third blow-air valve 23 has a dynamic seal 23a, which can provide a sealing effect when the third blow-air valve 23 moves along the longitudinal axis A.

[0099] A sealing surface is arranged between each of the blow-air valves. Specifically, a sealing surface 22c is arranged on the second blow-air valve 22 between the first and second blow-air valves 21 and 22. When these two blow-air valves 21 and 22 are in contact, this sealing surface blocks the fluid flow path for a gas flow that runs between these two blow-air valves 21 and 22 and towards the blow-jet opening 2. Furthermore, a sealing surface 23c is arranged on the third blow-air valve 23 between the second and third blow-air valves 22 and 23. When these two blow-air valves 22 and 23 are in contact, this sealing surface blocks the fluid flow path for a gas flow that runs between these two blow-air valves 22 and 23 and towards the blow-jet opening 2.

[0100] The first blow-air valve 21 is arranged at least partially inside the second blow-air valve 22 in a radial direction R that runs orthogonally to the longitudinal axis A.

[0101] A bar seal 25 is arranged between the pull-up bar 50 and the first air valve 21. The bar seal 25 is designed as a sliding seal, so that the pull-up bar 50 can move along the longitudinal axis A without moving the bar seal 25 with it. The bar seal 25 is arranged in a circumferential groove of the first air valve 21.

[0102] The blow-air valves 21, 22, 23 have valve seats 21b, 22b, 23b. The valve seats 21b, 22b, 23b are arranged at the nozzle-opening end of the blow-air valves 21, 22, 23 and are inclined relative to the longitudinal axis A, forming inclined surfaces, i.e., oriented at an angle of 45° relative to the longitudinal axis A. In the arrangement shown here, the valve seats 21b, 22b, 23b are located directly adjacent to the nozzle opening 2.

[0103] Furthermore, control means 15a, b, c, d, e, f are provided, by means of which the several compressed air valves 21, 22, 23 can each be adjusted axially along the longitudinal axis A. The control means include control air connections 15a, b, c, d, e, f, to which control air lines can be connected, so that control air can be supplied via the control air lines to adjust the compressed air valves 21, 22, 23 individually, and in particular independently of one another, in the axial direction along the longitudinal axis A. The compressed air valves 21, 22, 23 are thus pneumatically controllable.

[0104] A main blow line P2 is provided to supply the main blow pressure. Furthermore, an intermediate pressure line PB is provided to supply an intermediate pressure. Additionally, a vent line EXH is provided to vent the area of ​​the blow nozzle opening 2. An airbag line may also be provided to supply an air pressure return system.

[0105] Furthermore, a pre-blow pressure line P1 is provided to supply pre-blow pressure. However, in the embodiment described here, the pre-blow pressure is not introduced outside the pull-up bar 50, but rather through the pull-up bar 50 into the preform 80.

[0106] For this purpose, a horizontal bar flow path 55a is provided for guiding compressed air through the horizontal bar 50. The horizontal bar flow path 55a extends from a first horizontal bar opening 58 through a compressed air channel 55, which runs inside the horizontal bar 50, to a second horizontal bar opening 52.

[0107] The second opening 52 of the horizontal bar preferably comprises several outlet openings, which are arranged particularly in the region of the end section 51a of the horizontal bar. The outlet openings are preferably designed as bores. In the embodiment shown here, the outlet openings are aligned orthogonally to the longitudinal axis A and distributed symmetrically around the longitudinal axis A.

[0108] Inside the horizontal bar 50, a controllable compressed air channel valve 53 is arranged, which is adjustable between an open position, in which the compressed air channel valve 53 releases the horizontal bar flow path 55a, and a closed position, in which the compressed air channel valve 53 closes the horizontal bar flow path 55a. Thus, a valve is arranged inside the horizontal bar 50 that is adjustable between the open and closed positions in such a way that it can release and close the horizontal bar flow path 55a. When the compressed air channel valve 53 is in the closed position (as in Fig. 2When the compressed air channel valve 53 is arranged in the open position (as shown), it closes the pull-up bar flow path 55a, preventing compressed air from passing through the pull-up bar 50 via the pull-up bar. When the compressed air channel valve 53 is in the open position, it opens the pull-up bar flow path 55a, allowing compressed air to pass through the pull-up bar 50 via the pull-up bar. The compressed air channel valve 53 comprises a valve body 53a and a valve seat 53b.

[0109] In the flow path 55a, a compressed air throttle 52a is arranged between the compressed air channel valve 53 and the second pull-up bar opening 52. The throttle 52a is located in the region of the pull-up bar end section 51a and near the pull-up bar tip 51. The compressed air throttle 52a comprises a bore 52a extending along the longitudinal axis A.

[0110] A valve plunger 56 is connected to the compressed air channel valve 53. The compressed air channel valve 53 can be adjusted between the open and closed positions by means of the valve plunger 56, which is located at least partially within the pull rod 50 and within the compressed air channel 55. This is made possible by the valve plunger 56 performing an axial movement along the longitudinal axis A, which causes the compressed air channel valve 53, connected to the valve plunger 56, to also move along the longitudinal axis A.

[0111] Fig. 3 Figure 300 shows a schematic representation of a process for manufacturing containers from thermally conditioned preforms. The process comprises the following steps: In step 310, providing a fixture or a stretch blow molding machine, as shown in Figure 310. Fig. 1 or Fig. 2As described. In step 320, the valve block 10 is positioned so that the blow nozzle opening 2 seals against a preform 80 and / or a blow mold 70 holding the preform 80. In step 330, the first blow air valve 21 and / or the second blow air valve 22 are moved along the longitudinal axis A to open the fluid flow path that runs between the two blow air valves 21, 22 and to the blow nozzle opening 2. In step 340, pressure is applied to the preform 80 by means of a multi-stage forming process with several pressure stages. A low pre-blow pressure, P1 pressure, can initially be applied by introducing the pre-blow pressure through the drawbar flow path and into the preform. Subsequently, an intermediate pressure, PB pressure, can be applied which is higher than the pre-blow pressure.Subsequently, a main blowing pressure, P2 pressure, can be applied, which is higher than the intermediate pressure. Reference symbol list

[0112] 1 Blow nozzle 2 Blow nozzle opening 10 Valve block 10a-f Valve block seals 15a-f Control medium 19 Valve block end section 21 First blow air valve 21a First blow air valve seal 21b First blow air valve seat 22 Second blow air valve 22a Second blow air valve seal 22b Second blow air valve seat 22c Second blow air valve sealing surface 23 Third blow air valve 23a Third blow air valve seal 23b Third blow air valve seat 23c Third blow air valve sealing surface 25 Pull rod seal 30 Blow nozzle seal 50 Pull rod 52 Second pull rod opening 53 Compressed air channel valve 53a Valve body 53b Valve seat 55Compressed air channel 55aStretch rod flow path 56Valve tappet 58First stretch rod opening 59Valve piston 70Blow mold 71Blow mold half of the blow mold 72Blow mold half of the blow mold 80Preform 81Thread of the preform 90Container 100Stretch blow molding machine 116Forming station 120Blow wheel 122Feeding device 124Transfer wheel 126Temperature control device128 Heating elements 130 Transport device 132 Transfer wheel 134 Dispensing wheel 136 Dispensing section 300 Process 310-340 Process steps A Longitudinal axis EX Venting line P1 Pre-blow pressure line PB Intermediate pressure line P2 Main blow pressure line R Radial direction

Claims

1. Device for manufacturing containers (90) from thermally conditioned preforms, in particular from a thermoplastic, preferably of PET, with the device comprising - a blowing nozzle (1) for blowing compressed air into a preform (80) for forming the preform (80) into a container (90), wherein the blowing nozzle (1) comprises a blowing-nozzle opening (2), - a horizontal bar (50) for stretching the preform (80), which extends along a longitudinal axis (A) through the blowing nozzle (1) and at least partially within the blowing nozzle (1), and which is axially moveable for stretching the preform (80) relative to the blowing-nozzle opening (2), - a valve block (10) comprising a plurality of blowing air valves (21, 22, 23), which are axially moveable along the longitudinal axis (A) and within the valve block (10) and which are formed in a ring shape at least in sections, wherein at least two of the blowing air valves surround the horizontal bar (50) in a ring shape at least in sections, - wherein the plurality of blowing air valves (21, 22, 23) comprise a first blowing air valve (21) and a second blowing air valve (22), wherein the second blowing air valve (22) is arranged adjacent to the first blowing air valve (21), - wherein, between the first blowing air valve (21) and the second blowing air valve (22) a sealing surface (22c) is arranged on at least one of these two blowing air valves (21, 22) which, when these two blowing air valves (21, 22) are in contact with each other, blocks a fluid flow path for a fluid flow, in particular, for a gas flow, which runs between these two blowing air valves (21, 22) and to the blowing-nozzle opening (2) by means of a sealing effect, wherein the first blowing air valve (21) is arranged in a radial direction (R) which runs orthogonal to the longitudinal axis (A), at least partially within the second blowing air valve (22), characterized in that the blowing air valves (21, 22, 23) comprise valve seats (21b, 22b, 23b), wherein the valve seats (21b, 22b, 23b) are arranged at the end of the blowing-nozzle opening side of the blowing air valves (21, 22, 23) and are arranged at an angle relative to the longitudinal axis (A), wherein the valve seats (21b, 22b, 23b) are arranged immediately adjacent to the blowing-nozzle opening (2), wherein, in a position in which the blowing air valves (21, 22, 23) are closed, the valve seats (21b, 22b, 23b) are arranged at essentially the same height with respect to the longitudinal axis (A).

2. The device according to the preceding claim, wherein the plurality of blow air valves (21, 22, 23) comprise a third blow air valve (23) which is arranged adjacent to the second blow air valve (22), wherein preferably the second blowing air valve (22) and the third blowing air valve (23) are at least partially arranged in the radial direction (R) and / or wherein a horizontal bar seal (25) is arranged between the horizontal bar (50) and the first blowing air valve (21).

3. The device according to any one of the preceding claims, wherein the valve seats (21b, 22b, 23b) are arranged immediately adjacent to the blowing-nozzle opening (2), with a distance between the annular edge of the valve seats (21b, 22b, 23b) closest to the blowing-nozzle opening (2) and the blowing-nozzle opening (2) of less than 120 mm, preferably less than 60 mm, being particularly preferred, less than 20 mm.

4. The device according to any one of the preceding claims, wherein the blowing air valves (21, 22, 23) are designed in such a way that the projected surface overlaps at least partially when viewing in the direction of the longitudinal axis (A) of blowing air valves arranged adjacently.

5. The device according to any one of the preceding claims, comprising control means (15a, b, c, d, e, f), by means of which the plurality of blowing air valves (21, 22, 23) can be adjusted in the axial direction along the longitudinal axis (A), wherein, preferably, each of the blowing air valves (21, 22, 23) can be pneumatically controlled.

6. The device according to any one of the preceding claims, wherein the device comprises a plurality of lines, each controlled by one of the blowing air valves (21, 22, 23) with the device comprising - a pre-blow pressure line (P1) to provide a pre-blow pressure, and / or - a main blowing pressure line (P2) to provide a main blowing pressure, and / or - an intermediate pressure line (PB) to provide an intermediate pressure, and / or - a vent line (EXH) for bleeding the area of the blowing-nozzle opening (2), and / or - an airbag line to provide an air pressure recirculation system.

7. The device according to any one of the preceding claims, wherein the blowing nozzle (1) is adjustable in the axial direction along the longitudinal axis (A) between a blow mould in which the blowing-nozzle opening (2) is tightly attached to a preform (80) and / or to a blow mould (70) holding the preform (80) and a rest position in which the blowing-nozzle opening (2) is spaced apart from a preform (80).

8. The device according to any one of the preceding claims, comprising - a horizontal bar flow path (55a) for guiding compressed air through the horizontal bar (50), wherein the horizontal bar flow path (55a) extends from a first horizontal-bar opening (58) through the compressed air channel (55) to a second horizontal-bar opening (52), wherein a controllable compressed-air duct valve (53) is arranged inside the horizontal bar (50) which is adjustable between an open position in which the compressed air channel valve (53) releases the horizontal bar flow path (55a) and a closing position in which the compressed air channel valve (53) closes the horizontal bar flow path (55a).

9. The device according to any one of the preceding claims, wherein the horizontal bar (50) comprises a horizontal-bar end section (51a) with a horizontal-bar tip (51), wherein the compressed-air duct (55) inside the horizontal bar (50) extends to the horizontal-bar end section (51a), preferably to the horizontal bar tip (51), wherein, in the area of the end section of the horizontal bar (51a), the second opening of the horizontal bar (52) is arranged, which preferably comprises a plurality of outlet openings (52b, 52c) formed laterally on the horizontal bar (50), wherein the compressed-air duct valve (53) is preferably located in the area of the end section of the horizontal bar (51a), and preferably in the vicinity of the tip of the horizontal bar (51).

10. The device according to any one of the preceding claims, comprising a valve tappet (56) which is arranged at least partially within the stretching rod (50), and in particular at least partially within the compressed-air duct (55), wherein the valve tappet (56) is arranged and designed to adjust the compressed-air duct valve (53) between the opening and the closing position, preferably via a pure axial movement along the longitudinal axis (A), wherein the valve tappet (56) preferably comprises or consists of fibre-reinforced plastic, in particular, carbon fibre-reinforced plastic.

11. The device according to any one of the preceding claims, wherein the compressed-air duct valve (53) comprises a valve body (53a) and a valve seat (53b), wherein the valve body (53a) and the valve seat (53b) are formed and arranged to close the flow path (55a) in the closing position of the compressed-air duct valve (53) and to release the flow path (55a) in the opening position of the compressed-air duct valve (53), preferably via a pure axial movement along the longitudinal axis (A), wherein the valve body (53a) is preferably connected to the valve tappet (56) and / or the valve body (53a) is rotationally symmetrical in relation to the longitudinal axis (A).

12. The device according to any one of the preceding claims, wherein the second horizontal-bar opening (52) is located in the area of the end section of the horizontal bar (51a), preferably near the top of the horizontal bar (51), wherein in the flow path (55a), between the compressed-air duct valve (53) and the second horizontal-bar opening (52), a compressed air throttle (52a) is arranged, which is preferably located in the area of the end section of the horizontal bar (51a), in particular near the top of the horizontal bar (51).

13. The device according to any one of the preceding claims, wherein the compressed air throttle (52a) comprises a bore hole (52a) which extends preferably along the longitudinal axis (A), wherein preferably the bore hole (52a) comprises a diameter of at least 2 mm, preferably of at least 3 mm, and wherein preferably the bore hole (52a) comprises a diameter not exceeding 6 mm, preferably not more than 5 mm.

14. Stretch blow-moulding machine (100), comprising - a blowing wheel (120) comprising a plurality of blowing stations (116), wherein each of which of the blowing stations (116) comprises a device according to any one of the preceding claims.

15. A method (300) for manufacturing containers from thermally conditioned preforms consisting, in particular, of a thermoplastic material, in particular PET, comprising the steps: - providing (310) a device or a stretch-blow moulding machine according to any one of the preceding claims, - arranging (320) the valve block (10) in a position in which the blowing-nozzle opening (2) is tightly attached to a preform (80) and / or to a blow mould (70) holding the preform (80), - moving (330) the first blow air valve (21) and / or the second blow air valve (22) along the longitudinal axis (A) to release the fluid flow path running between the two blow air valves (21, 22) and to the blowing-nozzle opening (2) and preferably applying (340) a pressure in the preform (80).