Melt cooler, plastic molding device

Abstract

A melt cooler (800, 810) for a blown film apparatus with a film tube guide, wherein the film tube guide has a central channel for the film tube to pass through the melt cooler (800, 810) during operation of the blown film apparatus, wherein the melt cooler (800, 810) has cooling fluid guides (826, 830) and is designed to deliver cooling fluid entering the cooling fluid guides (826, 830) to the film tube passing through the melt cooler (800, 810) during operation of the blown film apparatus. The cooling fluid guides (826, 830) have manifolds (810, 812, 820) having cooling fluid outlets for conveying fluid, and the cooling fluid outlets convey cooling fluid to the channel. A plastic molding apparatus, particularly a blown film apparatus or a flat film apparatus, or some other apparatus designed for producing film webs, has a processing section and a melt cooler (800, 810). A method for cooling the melt in a film tube of a blown film apparatus using a melt cooler (800, 810).

Description

Technical Field

[0001] This invention relates to a melt cooler, a plastic molding apparatus, and a melt cooling method.

[0002] More specifically, the present invention relates to a melt cooler for a blown film apparatus having a film tube guide, wherein the film tube guide has a central channel for the film tube to pass through the melt cooler during operation of the blown film apparatus. Furthermore, the present invention relates to a plastic molding apparatus, particularly a blown film apparatus or a flat film apparatus, or some other apparatus designed for producing film webs, having a processing section, wherein the processing section has a melt cooler. Additionally, the present invention relates to a method for cooling the melt of the film tube of a blown film apparatus using a melt cooler. Background Technology

[0003] Blown film apparatuses are known and validated in the prior art: plastic granules are melted in an extruder and fed through a pre-dispensing device into a blown head with a helical manifold. The melt enters through a helical auger into an annular gap leading to an annular slit nozzle. The melt is extruded from the annular slit nozzle to form a film tube. Due to the increased internal pressure within the film tube, it widens immediately upon exiting the annular slit nozzle in the so-called tube-forming zone and typically in the subsequent cooling ring, which stretches the film particularly transversely to the machine direction. The film is then cooled, calibrated, flattened, and then typically reoriented and wound. In the take-off unit, in addition to cooling, calibrating, and flattening, a pair of extrusion rollers are typically provided, at least one of which is driven, and the circumferential speed of the roller is greater than the exit speed of the melt tube at the annular slit nozzle. This results in an additional longitudinal stretching of the film tube.

[0004] In addition to the take-off device, there is usually a reversing device with a steering rod. During reversing, the steering rod rotates cyclically around the vertical axis before the film web is finally fed into the winding table and wound thereto to form a film roll.

[0005] The thickness distribution of the thin film tubes produced by this process is usually not completely uniform around the circumference.

[0006] The membrane tube arrives at the extraction unit in a cured state. Therefore, the membrane tube must be cooled after leaving the annular slit nozzle.

[0007] There are several ways to cool the thin-film tube.

[0008] Cooling rings have proven to be very effective. Typically, the cooling ring is positioned directly on or at least close to the annular nozzle to allow for maximum heat application to the melt. Most cooling rings are stationary, although their height can be advantageously adjusted.

[0009] A cooling ring is arranged on the outside of the diaphragm tube and has a circular channel inside for the diaphragm tube. Cooling air is blown into the cooling ring from the outside and discharged inward onto the diaphragm tube through cooling air nozzles. The cooling ring is also a useful method to influence the cooling performance of the diaphragm tube: it allows for the variation of the cooling air temperature. Some cooling rings even have small mechanical actuators inside the cooling air guides, which affect the airflow of the blown-in cooling air, allowing the cooling air to be distributed around the circumference of the cooling ring and guided onto the diaphragm tube in a non-uniform manner from the cooling ring or from the cooling air nozzles. This allows for the elimination of irregularities in the thickness of the diaphragm tube along its circumference.

[0010] Since the applicant of this patent application currently designs its extrusion device in a vertical direction under the influence of gravity, reference will primarily be made to this direction below. However, it should be clearly noted that the invention can also be applied to all other spatial directions. Those skilled in the art will be able to similarly adapt the features disclosed herein if needed.

[0011] The reversing device ensures that film thickness non-uniformity does not manifest as a single location of excessive thickening within the film roll. However, for some film products, it is desirable to improve film thickness uniformity.

[0012] Gravity compression creates the possibility of cooling the membrane tube, which does not occur during anti-gravity compression—that is, upward compression. Therefore, the membrane tube can be cooled with water, for example. To this end, the membrane tube is inflated with air after an annular slit nozzle and guided through a bushing, which calibrates and defines the membrane tube circumference. Due to the increased pressure within the membrane tube, it widens in the tube-forming region and abuts against the inner wall of the bushing. Typically, cooling water flows through this bushing in addition to the membrane tube. Typically, the cooling water is arranged between the membrane tube and the bushing; this prevents the membrane tube from sticking to the side surface of the bushing. At or immediately after the bushing end, the cooling water is drawn out again, allowing the membrane tube to be further transported along the membrane tube guide in a relatively dry state. Summary of the Invention

[0013] According to the first aspect, the above objective is achieved by a melt cooler for a blown film apparatus. The blown film apparatus has a film tube guide, wherein the film tube guide has a central channel for the film tube to pass through the melt cooler during operation of the blown film apparatus. The melt cooler has a cooling fluid guide, configured to deliver cooling fluid introduced into the cooling fluid guide to the film tube passing through the melt cooler during operation of the blown film apparatus. The cooling fluid guide has a manifold with a cooling fluid outlet for conveying fluid. The cooling fluid outlet conveys the cooling fluid to the channel.

[0014] The following explains the relevant terms.

[0015] It should be clearly pointed out that, within the scope of this patent application, indefinite articles and indefinite numbers, such as “a,” “two,” etc., should generally be understood as “at least one,” “at least two,” etc., unless it is clearly apparent from the context or the specific text of a particular paragraph that it only indicates “exactly one” and “exactly two.” Furthermore, all numbers and all information regarding method parameters and / or device parameters should be understood in a technical sense, i.e., taking into account common tolerances. Even the explicit use of restrictive terms such as “at least” does not imply the use of only “a” (a), that is, the absence of “at least” or similar words means “exactly one.”

[0016] The film tube guide is part of the blown film device, located between the blown head and the winding machine. Initially, the viscous plastic melt is discharged from the blown head in the form of a film tube. The winding machine eventually winds the film roll that has hardened to this point into a double-layer film roll, which may be further processed.

[0017] The melt cooler is preferably located in the tube-forming zone. The tube-forming zone is the area between the annular slit nozzles from which the melt is extruded into a thin film tube, and subsequently widened by increased internal pressure within the film tube. A cooling ring typically follows the annular slit nozzles to cool the film tube from the outside. In the tube-forming zone, the film tube is stretched, particularly transversely to the machine direction. The film is then calibrated, that is, its outer circumference is adjusted to the desired dimensions.

[0018] Particularly preferred is that the melt cooler is located in the tube forming zone between the annular slit nozzle and the thin film tube calibration device.

[0019] The cooling fluid guide preferably has at least one connection for the cooling fluid. The cooling fluid guide is preferably configured to distribute the cooling fluid evenly. For this purpose, a channel can be provided, for example, by adjusting the cross-section of the channel to allow for uniform delivery of the cooling fluid. A cooling fluid outlet enables the delivery of the cooling fluid. The cooling fluid outlet is preferably formed by multiple openings from which the cooling fluid flows out. The cooling fluid is preferably delivered directly along the direction of the channel. For example, a diaphragm or lip can be provided to guide the cooling fluid in a specific direction. Such a guiding element can cause the cooling fluid to deflect upwards or downwards after impacting the diaphragm tube. The manifold is preferably configured to form a buffer pad with the discharged cooling fluid, allowing the passing diaphragm tube to pass through the melt cooler without contact. This pad ensures that the surface of the diaphragm tube is not damaged.

[0020] In an embodiment of the first aspect of the invention, the melt cooler has a frame configured to accommodate a manifold.

[0021] The melt cooler is particularly easy to assemble and / or disassemble due to its frame design that accommodates the manifold.

[0022] For example, assembly and / or disassembly are performed when the melt cooler needs cleaning. For this purpose, the manifold can be removed from the frame, for example, and monomer residues and other contaminants can be removed. For cleaning, it is also conceivable to allow cleaning fluid, rather than cooling fluid, to flow through the melt cooler. This cleaning is preferably not performed during operation of the blown film apparatus. The frame can be configured in multiple sections, and the manifold can be housed between these sections. The frame may include a cooling fluid guide, which may, for example, be arranged in a recess behind the manifold. A sealing element may be provided between the frame and the manifold to prevent cooling fluid from leaking out at undesirable locations.

[0023] In one embodiment of the melt cooler, the melt cooler is configured as a ring arranged around the thin film tube.

[0024] Because the melt cooler is designed to be annular, it is particularly advantageous to arrange it in the tube-forming region surrounding the thin-film tube. Since the formed thin-film tube is typically circular, an annular melt cooler is especially suitable for uniform cooling.

[0025] In one embodiment of the melt cooler, the melt cooler is configured as a ring arranged within a thin-film tube.

[0026] The melt cooler can be housed inside the membrane tube. In this design, it is also advantageous to configure the melt cooler as a ring.

[0027] In one embodiment, the melt cooler may have internal and external manifolds, such that the film tube is cooled from both sides by the melt cooler, that is, from the inside and the outside. For example, the internal melt cooler may be mounted at the center of the annular nozzle. The internal melt cooler is preferably movable between a start-up position and an operating position, thereby facilitating the start-up of the blown film device.

[0028] In one embodiment of the melt cooler, the cooling fluid outlet has orifices through which the cooling fluid can be delivered.

[0029] The manifold is preferably perforated. This perforation allows cooling fluid to be transported through the holes. Porosity is a dimensionless measurement and represents the ratio of cavity volume to the total volume of a substance or mixture of substances. It serves as a classification measure for actual cavities. This variable is applied in materials and structural engineering. Porosity has a significant impact on the density of materials and the resistance to flow through the bed (Darcy's Law). Originally caused by natural conditions and often undesirable, especially in the production of complex castings, manifolds are now also artificially created and are desirable in this regard. The manifold is preferably made of porous metal foam, particularly aluminum foam.

[0030] The manifold preferably has a density of 1 to 3 g / cm3, and the manifold is particularly preferably 1.8 g / cm3.

[0031] According to DIN EN ISO 868, manifolds preferably have a Rockwell hardness D of 75 to 95, and manifolds particularly preferably have a Rockwell hardness D of 85.

[0032] The manifold preferably has a modulus of DIN EN ISO 527E of 5000 N / mm2 to 7000 N / mm2, and the manifold is particularly preferably an E modulus of 6000 N / mm2 to 6200 N / mm2.

[0033] According to DIN EN ISO 604, manifolds preferably have a compressive strength of 25 to 36, and manifolds particularly preferably have a compressive strength of 29 to 33.

[0034] The total porosity of the manifold is preferably between 5% and 45%. Particularly preferred is a total porosity between 15% and 25%.

[0035] In one embodiment of the melt cooler, the average pore diameter is less than 50 μm. The average pore diameter of the manifold is preferably between 2 μm and 50 μm. Particularly preferably, the average pore diameter is between 8 μm and 18 μm.

[0036] In one embodiment of the melt cooler, the manifold has multiple sections. Preferably, the manifold consists of multiple sections.

[0037] The segmented structure of the manifold is particularly advantageous during cleaning because it allows for sequential cleaning of each segment. Therefore, manifold cleaning devices can be made in smaller sizes. Furthermore, the production of segmented manifolds may be more economical. If a surface of the manifold is defective, only the individual segment needs to be replaced due to the segmented design. Also, if one section of the manifold is damaged, the entire manifold does not need to be replaced.

[0038] For example, the segments can be bonded together. For cleaning purposes, this bonding is preferably done in a removable manner. For example, to avoid visible residue from adhesive or adjacent segment edges, the segment edges between segments can extend diagonally rather than simply perpendicularly. This diagonal profile minimizes the impact of such segment edges or adhesive on the membrane surface of the membrane tube.

[0039] In one embodiment of the melt cooler, the melt cooler is configured such that the cooling fluid is delivered along the travel direction of the thin film tube.

[0040] This design allows for particularly efficient use of the cooling fluid, as it does not escape into areas where there is no cooling effect or into areas where the cooling effect is reduced.

[0041] In one embodiment of the melt cooler, the melt cooler has an actuator for mechanically regulating the volumetric flow rate of the cooling fluid during operation.

[0042] Due to this design with an actuator for mechanically regulating volumetric flow rate, cooling fluid can be selectively delivered to various areas of the film tube surface. By selectively delivering cooling fluid to the surface of the film tube, flatness defects on the film tube surface can be compensated for with particular precision. In this context, it is preferable that the blown film apparatus has a device for detecting flatness defects on the film tube surface. This can be arranged in the production direction before or after the melt cooler. If it is arranged after the melt cooler, then the flatness defects on the film tube surface need to be preferably automatically assigned to the corresponding locations on the melt cooler.

[0043] In one embodiment of the melt cooler, the cooling fluid outlet has a gradient relative to the direction of travel of the thin film tube, which gives the volumetric flow rate of the cooling fluid a defined distribution.

[0044] Preferably, the cooling fluid outlet delivers different amounts of cooling fluid to the membrane tube according to the direction of travel of the membrane tube. For example, particularly gentle cooling of the melt can be achieved by a gradient, where a smaller amount of cooling fluid is delivered to the membrane tube at the beginning of the melt cooler based on the direction of travel of the membrane tube, and the amount of cooling fluid is increased along the direction of travel of the membrane tube. Conversely, particularly rapid cooling of the membrane tube can also be achieved by a gradient, where more cooling fluid is initially delivered to the membrane tube and then the amount of cooling fluid reaching the membrane tube is reduced.

[0045] In one embodiment of the melt cooler, the melt cooler has a temperature control device that allows the cooling fluid to reach a predetermined temperature.

[0046] The temperature control device can be, for example, a heating device that brings the cooling fluid to a predetermined temperature before it reaches the diaphragm tube. Similarly, the temperature control device can also be a cooling device. Preferably, the temperature control device is connected to a sensing device. The sensing device is preferably configured to detect temperature via one or more sensors. For example, such sensors can be used to detect the temperature of the cooling fluid before and / or after the temperature control device. Furthermore, such sensors can be used to detect the temperature of the diaphragm tube surface. Detecting the surface temperature of the diaphragm tube before and after the melt cooler may be advantageous.

[0047] In one embodiment of the melt cooler, it has multiple manifolds arranged vertically relative to the direction of travel of the thin-film tube. For example, by arranging the manifolds vertically, the aforementioned gradient can be achieved in a particularly simple manner. Furthermore, by using multiple manifolds arranged vertically, a gentler cooling process can be achieved.

[0048] In one embodiment of the melt cooler, the melt cooler is configured to be positionally adjustable within the blown film apparatus. Preferably, the melt cooler is horizontally movable.

[0049] For example, adjustability refers to the ability to move the melt cooler to a maintenance position. This adjustability is particularly important when the blown film unit is stationary or running. In this maintenance position, for example, cleaning or disassembly of the melt cooler can also be performed.

[0050] In one embodiment of the melt cooler, the melt cooler is configured to be adjustable in its position within the blown film apparatus during operation of the blown film apparatus. Preferably, the melt cooler is configured to be adjustable in its transverse and / or longitudinal and / or height directions relative to the direction of travel of the film tube.

[0051] Preferably, the melt cooler is adjustable along its vertical axis. This allows its position relative to the film tube to be adjusted during operation of the blown film apparatus. If the melt cooler is adjustable along its longitudinal and / or transverse axes, it can be moved relative to the film tube by rolling and / or pitching. Due to the adjustability during operation of the blown film apparatus, the melt cooler can act particularly precisely on the film tube. For example, it can compensate for and / or correct for non-horizontal cooling lines of the melt.

[0052] In one embodiment of the melt cooler, the melt cooler has an inner diameter of 200 mm to 1800 mm. Preferably, the inner diameter of the melt cooler is adjusted to the calibration diameter of the thin film tube.

[0053] The ratio of the inner diameter of the melt cooler to the calibration diameter of the thin-film tube can be 1:1. In some embodiments, the inner diameter of the melt cooler can also be reduced by adjusting the inlet shape. Preferably, the inner diameter of the melt cooler can be adjusted according to the machine.

[0054] In one embodiment of the melt cooler, the height of the manifold is 4 mm to 200 mm relative to the direction of travel of the membrane tube. Preferably, the height of the melt cooler is 50 mm to 70 mm.

[0055] In one embodiment of the melt cooler, the cooling fluid outlet for conveying the fluid has an angle of 0° to 40° relative to the travel direction of the diaphragm tube; preferably, the cooling fluid inlet for conveying the fluid has an angle of 1° to 10° relative to the travel direction of the diaphragm tube. Preferably, the cooling fluid outlet for conveying the fluid is tangent to the travel direction of the diaphragm tube.

[0056] In one embodiment of the melt cooler, the melt cooler has a mating structure arranged on the surface of the thin film tube away from the melt cooler.

[0057] Particularly preferably, the melt cooler is arranged on the outside of the entire tube. In particular, this externally arranged melt cooler is advantageous when combined with a water-cooled calibration device, because cooling the surface of the membrane tube can make the surface of the membrane tube smoother.

[0058] The mating structure can be configured, for example, as an internal coolant. The mating structure is preferably arranged within a diaphragm tube following the annular nozzle. In a particularly advantageous embodiment, the mating structure can be adjusted relative to the direction of travel of the diaphragm tube to a height position relative to the melt cooler. For example, this mating structure can prevent retraction when cooling fluid is applied to the melt cooler. The mating structure preferably has its own melt cooler, which is configured according to the melt cooler of the invention and delivers cooling fluid to the surface of the diaphragm tube.

[0059] In one embodiment of the melt cooler, the melt cooler has segmented elements that can be guided to the location of the thin film tube.

[0060] Therefore, the melt cooler can have multiple radially retractable segmented elements. The individual segments are adjusted to form an assembled melt cooler in one operating position.

[0061] In one embodiment of the melt cooler, the cooling fluid comprises a gas. Air is particularly preferred as the cooling fluid.

[0062] Air can be pumped and / or compressed into the melt cooler and delivered through its pores. In embodiments, the gas may also be a mixture of rare gases and / or gaseous fluids. For cleaning purposes, a cleaning fluid, instead of a cooling fluid, may be introduced into the system. The cleaning fluid may, for example, include a solvent.

[0063] In one embodiment of the melt cooler, the melt cooler is configured to cool the fluid at a volumetric flow rate of 0.1 L / min / cm² to 1 L / min / cm² at a pressure of 1 bar.

[0064] In one embodiment of the melt cooler, the melt cooler is configured to cool the surface of the thin-film tube by 0.5° to 20° Kelvin. By cooling the surface relatively low, the surface is preferably cooled only to a degree with sufficient strength so that it does not bend during subsequent calibration.

[0065] In one embodiment of the melt cooler, the melt cooler is configured to cool the surface of the melt. In this case, the melt surface of the membrane tube is preferably understood as a layer of the membrane tube with a film thickness in the range of 0.1 micrometers to 4 micrometers.

[0066] In one embodiment of the melt cooler, the melt cooler is used in a blown film device, wherein a thin film tube is extruded from top to bottom.

[0067] In this design, the melt cooler is particularly advantageous because, during the top-down extrusion process, the weight of the film tube pulls it downwards. The surface of the melt can be cooled and thus stabilized by the melt cooler, allowing the surface to harden considerably without any smoothness defects.

[0068] In one embodiment of the melt cooler, the melt cooler is arranged upstream of the water cooling device of the membrane tube relative to the direction of travel of the membrane tube.

[0069] According to a second aspect of the invention, the object of the invention is achieved by a plastic molding apparatus, particularly a blown film apparatus or a flat film apparatus, or some other apparatus designed for producing film webs, having a processing section, wherein the plastic molding apparatus has a melt cooler of the type described above on the processing section.

[0070] In one embodiment of the second aspect of the invention, the plastic molding apparatus is configured as a blown film apparatus.

[0071] In one embodiment of the second aspect of the invention, a melt cooler is arranged on a processing section after the blown film head. Preferably, the melt cooler is arranged after the blown film head and before the calibration device.

[0072] In one embodiment of the second aspect of the invention, a blown film apparatus is provided for extruding a film tube from top to bottom. In this apparatus, the film tube is extruded under gravity, rather than expanding upwards as in other apparatuses.

[0073] In one embodiment of the second aspect of the invention, the blown film apparatus has a cooling unit for the film tube, wherein water is used as the cooling medium. Preferably, the cooler is used in conjunction with a calibration device. The cooler is configured such that the film tube passes through a bushing, and due to expansion, the film tube abuts against the bushing from the inside and is calibrated to a predetermined circumference. For simultaneous cooling, water is directed onto the film tube and through the bushing, cooling the film tube and at least partially hardening the melt.

[0074] In one embodiment of the second aspect of the invention, a melt cooler is arranged on a processing section after the blown film head and before the film tube cooling unit.

[0075] According to a third aspect of the invention, the above-mentioned objective is achieved by a method for cooling the melt of a thin film tube in a blown film apparatus using a melt cooler of the type described above. By this method, the surface of the thin film tube is cooled by a cooling fluid.

[0076] In one embodiment of the third aspect of the invention, the surface of the thin film tube is cooled by 1° to 30° Kelvin in the melt cooler region.

[0077] Preferably, only the surface of the thin-film tube is cooled, rather than the entire thin-film tube. Preferably, the melt cooler should ensure that the surface of the thin-film tube hardens so that it is not compressed within the cooling unit. This ensures that the surface of the entire tube remains exceptionally smooth.

[0078] In one embodiment of the third aspect of the invention, the irregularity of the surface temperature of the thin-film tube is compensated by the adjustability of the melt cooler relative to the direction of travel of the thin-film tube in its longitudinal and / or transverse and / or height. Preferably, the irregularity of the entire tube surface can be compensated by the adjustability of the melt cooler in its longitudinal, transverse and / or vertical axes. Attached Figure Description

[0079] The invention will now be explained in more detail with reference to the accompanying drawings and exemplary embodiments, wherein:

[0080] Figure 1 A perspective view of a blown film apparatus with a generally bottom-to-top production direction is shown;

[0081] Figure 2 A perspective view of a blown film apparatus with a generally top-to-bottom production direction is shown;

[0082] Figure 3 A detailed schematic diagram of a blown film device according to the present invention is shown, which has a top-to-bottom production direction from the nozzle to the back of the calibration area;

[0083] Figure 4 The frame of a multi-component melt cooler excluding the manifold is shown;

[0084] Figure 5 The manifold of a multi-component melt cooler excluding the frame is shown;

[0085] Figure 6 It shows Figure 5 Cross-section of the central manifold;

[0086] Figure 7A cross-section of a multi-component melt cooler with a frame and a manifold sandwiched within it is shown. Detailed Implementation

[0087] Figure 1 The blown film apparatus shown has a production direction x from bottom to top. The extruder area 100 of the blown film apparatus is located at the bottom, i.e., at the floor level of the production workshop. Multiple extruders 101 operate on blown heads having annular nozzles 110 (not shown). The film tube, inflated through the annular nozzles, is discharged from the annular nozzles 110, thus forming a film bubble 600. The film tube is radially stretched due to expansion.

[0088] In the production direction x, a cooling ring 700 is provided after the annular nozzle 110. In various embodiments, the cooling ring 700 may have a different number of lips. For example, cooling rings with one, two, or even three cooling ring lips 704, 705 are also known. Cooling fluid is brought into contact with the outside of the membrane bubble 600 through cooling fluid nozzles 702, 703, and the membrane bubble 600 is cooled from the outside within the cooling ring 700. In the production direction x, the outer diameter of the calibration membrane bubble 600 is calibrated in calibration region 200. Following calibration region 200 in the production direction is a take-out region 300, in which the membrane tube is squeezed and taken out by a pair of rollers. Through squeezing, expansion pressure is confined within the membrane bubble 600. Upon take-out, the membrane bubble is stretched in the axial direction, resulting in a biaxially stretched consolidated membrane tube after take-out region 300. Following take-out region 300 in the production direction x, a stretching region 400 is provided, in which the consolidated membrane tube is further stretched axially. Behind the stretching zone, the flattened film tube is reoriented and guided back to the level of the extruder zone 100, i.e., at ground level on the floor of the production workshop, where the film tube is wound in the winding zone 500. The general bottom-to-top production direction x is the typical direction of the blown film device, in which air is used to cool the film bubble 600.

[0089] Figure 2The blown film apparatus shown has a general production direction x from top to bottom. The extruder area 100 of the blown film apparatus is arranged at the top, i.e., above all other mounting components. Multiple extruders 101 operate on a blown head having an annular nozzle 110 (not shown). A film tube inflated through the annular nozzle is discharged from the annular nozzle 110, thus forming a film bubble 600. The film tube is radially stretched due to expansion. In the production direction x, a cooling ring 700 is provided after the annular nozzle 110. In various embodiments, the cooling ring 700 may have different numbers of lips. For example, cooling rings with one, two, or even three cooling ring lips 704, 705 are also known. The general top-to-bottom production direction x is the typical direction of the blown film apparatus, in which the film bubble 600 is cooled in the cooling ring 700 by a liquid cooling fluid—such as water. This is because in this production direction x, the liquid cooling fluid film can generally be applied to the film bubble 600 by gravity. Cooling fluid is brought into contact with the outside of the membrane bubble 600 through cooling fluid nozzles 702 and 703, and the membrane bubble 600 is cooled from the outside in the cooling ring 700. In the production direction x, a calibration region 200 is included, in which the outer diameter of the membrane bubble 600 is calibrated. Following the calibration region 100 in the production direction, a take-out region 300 is included, in which the membrane tube is squeezed and taken out by a pair of rollers. Through squeezing, expansion pressure is confined within the membrane bubble 600. Upon take-out, the membrane bubble is stretched in the axial direction, resulting in a biaxially stretched consolidated membrane tube after the take-out region 300. In the illustrated embodiment, a stretching region 400 is included after the take-out region 300, in which the consolidated membrane tube is further stretched axially. The membrane tube is redirected to the stretching region because, in this embodiment, for spatial reasons, the stretching region 400 is arranged next to but above the stretching region. Behind the stretching zone, the flattened film tube is reoriented and guided back to the level of the take-out zone 300, that is, the floor level on the production workshop floor, where the film tube is wound in the winding zone 500.

[0090] Figure 3 A detailed schematic diagram of the blown film apparatus according to the invention, extending from nozzle 110 to the calibration region 200, is shown. The film tube extruded from nozzle 110 expands to form a film bubble 600 and initially passes through a cooling ring 700, in which the exterior of the film bubble 600 is cooled by the cooling fluid through contact with the exterior of the film bubble 600.

[0091] The membrane bubble 600 then passes through the calibration region 200, in which the outer diameter of the membrane bubble is calibrated.

[0092] Figure 4A frame 820 of a multi-component melt cooler is shown. In one embodiment, the melt cooler 800 is configured as a ring. The melt cooler 800 is designed to use air as the cooling medium. The frame 820 is shown excluding the manifold 810. The frame 820 has a plurality of cooling fluid inlets 824 on its outer surface 822. In this embodiment, the frame 820 is made of stainless steel. The cooling fluid inlets 824 are configured to use air as the cooling medium. In this embodiment, the cooling fluid inlets 824 have an inlet angle of less than 90° relative to the radius to better distribute the incoming air into the cooling fluid guides.

[0093] Figure 5 The manifold 810 of the melt cooler 800 is shown. The manifold 810 is formed of porous aluminum. The density of the manifold 810 is 1.8 g / cm³. The average pore size of the manifold 810 is 12 micrometers. The total porosity is 21%.

[0094] Figure 6 It shows Figure 5 The cross-section of the manifold 810 is shown. It can be seen that the manifold 810 has an upper inlet region 812, which forms a widened inlet for the film tube 600 during operation of the blown film device. The inlet region 812 prevents the film tube 600 from being compressed on the manifold 810 and, in the worst case, prevents tearing.

[0095] Figure 7 A cross-section of the melt cooler 800 in its assembled state is shown. A manifold 810 is clamped between multiple components 830, 831, and 832 of a frame 820. Multiple sealing elements 834 and 836 are provided between the manifold 810 and components 830 and 832 to prevent the cooling medium from leaving between the frame 820 and the manifold 810. The portion of the manifold 810 shown also shows a cooling fluid inlet 824 on its outer surface 822, which is fluidly connected to a cooling fluid guide 826. A diaphragm tube 600 slides over an air cushion 814 on the manifold 810.

[0096] The embodiments shown herein are merely examples of the invention and should therefore not be construed as limiting. Alternative embodiments that may occur to those skilled in the art are also included within the scope of this invention.

[0097] List of reference numerals in the attached diagram:

[0098] 100 Extruder Area

[0099] 101 Extruder

[0100] 110 Annular nozzle, nozzle

[0101] 200 calibration areas

[0102] 300 Take-out area

[0103] 400 stretch zone

[0104] 500 winding area

[0105] 600 membrane bubble / thin film tube

[0106] 700 cooling ring, double-lip cooling ring

[0107] 800 Melt Cooler

[0108] 810 manifold

[0109] 812 Entrance Area

[0110] 814 Air Cushion

[0111] 820 frame

[0112] 822 side surface

[0113] 824 Cooling fluid inlet

[0114] 826 Cooling Fluid Deflector

[0115] 830 Framework Components

[0116] 831 Framework Components

[0117] 832 Framework Components

[0118] 834 Sealing element

[0119] 836 Sealing element

[0120] x Production direction

Claims

1. A melt cooler for a blown film apparatus having a thin film tube guide, wherein, The film tube guide has a central channel for the film tube to pass through the melt cooler during operation of the blown film apparatus. The melt cooler has a cooling fluid guide designed to deliver cooling fluid introduced into the cooling fluid guide to the film tube passing through the melt cooler during operation of the blown film apparatus. The cooling fluid guide has a manifold with a cooling fluid outlet for conveying fluid, and the cooling fluid outlet delivers cooling fluid to the channel. The melt cooler is configured as a ring that can be arranged around the thin film tube, or the melt cooler is configured as a ring that can be arranged inside the thin film tube.

2. The melt cooler according to claim 1, characterized in that, The melt cooler has a frame configured to accommodate the manifold.

3. The melt cooler according to claim 1 or 2, wherein, The manifold has an orifice that serves as a cooling fluid outlet, through which the cooling fluid can be delivered.

4. The melt cooler according to claim 3, wherein, The average diameter of the hole is less than 50µm.

5. The melt cooler according to claim 4, wherein, The average diameter of the pores is between 2µm and 50µm.

6. The melt cooler according to claim 5, wherein, The average pore diameter is between 8µm and 18µm.

7. The melt cooler according to claim 1 or 2, wherein, The manifold consists of several segments.

8. The melt cooler according to claim 7, wherein, The segments are combined with each other to form the manifold.

9. The melt cooler according to claim 1 or 2, wherein, The melt cooler is configured such that the cooling fluid is delivered along the travel direction of the thin film tube.

10. The melt cooler according to claim 1 or 2, wherein, The melt cooler has an actuator for mechanically regulating the volumetric flow rate of the cooling fluid.

11. The melt cooler according to claim 1 or 2, wherein, The cooling fluid outlet has a gradient relative to the direction of travel of the thin film tube, and the gradient causes the volumetric flow rate of the cooling fluid to have a defined distribution.

12. The melt cooler according to claim 1 or 2, wherein, The melt cooler has a temperature control device, which enables the cooling fluid to reach a predetermined temperature.

13. The melt cooler according to claim 1 or 2, wherein, The melt cooler has multiple manifolds arranged vertically relative to the direction of travel of the thin film tube.

14. The melt cooler according to claim 1 or 2, wherein, The melt cooler is configured to be positionally adjustable within the blown film apparatus.

15. The melt cooler according to claim 14, wherein, The melt cooler is capable of horizontal movement.

16. The melt cooler according to claim 1 or 2, wherein, The melt cooler is configured to be positionally adjustable within the blown film apparatus during operation.

17. The melt cooler according to claim 16, wherein, The melt cooler is configured to be adjustable relative to the direction of travel of the thin film tube along its horizontal and / or vertical axis and / or height.

18. The melt cooler according to claim 1 or 2, wherein, The inner diameter of the melt cooler is 200 mm to 1800 mm.

19. The melt cooler according to claim 18, wherein, The inner diameter of the melt cooler is adjusted to the calibration diameter of the thin film tube.

20. The melt cooler according to claim 1 or 2, wherein, The height of the manifold is 4 mm to 200 mm relative to the direction of travel of the membrane tube.

21. The melt cooler according to claim 20, wherein, The height of the melt cooler is 50mm to 70mm.

22. The melt cooler according to claim 1 or 2, wherein, The cooling fluid outlet for conveying fluid has an angle of 0° to 40° relative to the direction of travel of the membrane tube.

23. The melt cooler according to claim 22, wherein, The cooling fluid outlet for conveying fluid has an angle of 1° to 10° relative to the direction of travel of the membrane tube.

24. The melt cooler according to claim 1 or 2, wherein, The melt cooler has a mating structure arranged on the surface of the thin film tube away from the melt cooler.

25. The melt cooler according to claim 1 or 2, wherein, The melt cooler has segmented elements that can be guided to the thin film tube.

26. The melt cooler according to claim 1 or 2, wherein, The melt cooler is used to cool the gaseous fluid.

27. The melt cooler according to claim 1 or 2, wherein, The melt cooler is configured to provide a volumetric flow rate of the cooling fluid of 0.1 L / min / cm² to 1 L / min / cm² at a pressure of 1 bar.

28. The melt cooler according to claim 1 or 2, wherein, The melt cooler is configured to cool the surface of the thin film tube by 0.5° Kelvin to 20° Kelvin.

29. The melt cooler according to claim 1 or 2, wherein, The melt cooler is configured to cool the surface of the melt.

30. The melt cooler according to claim 1 or 2, wherein, The melt cooler is configured for a blown film device in which the film tube is extruded from top to bottom.

31. The melt cooler according to claim 1 or 2, wherein, The melt cooler is positioned upstream of the water cooling device of the thin film tube, relative to the direction of travel of the thin film tube.

32. A plastic molding apparatus, particularly a blown film apparatus or a flattened film apparatus, or some other apparatus designed for producing film webs, comprising a processing unit, wherein, The processing unit includes a melt cooler according to any one of claims 1 to 31.

33. The plastic molding apparatus according to claim 32, characterized in that, The plastic molding device is a blown film device.

34. The plastic molding apparatus according to claim 33, characterized in that, The melt cooler is arranged on the processing section, located after the blown film head.

35. The plastic molding apparatus according to any one of claims 32 to 34, characterized in that, The blown film device extrudes a thin film tube from top to bottom.

36. The plastic molding apparatus according to any one of claims 32 to 34, characterized in that, The blown film device has a cooling unit for the thin film tube, wherein the cooling unit uses water as the cooling medium.

37. The plastic molding apparatus according to claim 36, characterized in that, The melt cooler is arranged on the processing section, located after the blown film head and before the cooling unit of the thin film tube.

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