Filter device for filtering polymer melt

Abstract

The invention relates to a filter device (1) for separating impurities from a polymer melt as it flows in a flow direction of a hot runner mould through the filter device (1), which can be fixed in position within a hot runner or an injection moulding machine and comprises a filter element (2) having a first end region (4) and a second end region (5) opposite the first end region (4), wherein a wall (6) of the filter element (2) comprises a first first wall section (12) designed as a truncated cone and the filter element (2) has a perforated design. The filter device (1) is designed without a casing and has a first collar (10) coupled to the filter element (2) in the first end region (4) and a second collar (11) coupled to the filter element (2) in the second end region (5), so that the filter device (1) can be axially positioned within the hot runner and in the flow direction by means of the first collar (10) and / or the second collar (11).

Description

[0001] FILTER DEVICE FOR FILTERING POLYMER MELTS

[0002] The invention relates to a filter device for separating impurities such as foreign matter from a polymer melt for or in a hot runner tool, for example for an injection molding machine, wherein the filter device can be positioned or fixed in position in a pipe or line or flow chamber and wherein impurities or foreign matter are filtered or can be filtered by means of the filter device as they flow through it in a flow direction.

[0003] A filter device of this type is known, for example, from DE 19 915 700 A1. In this filter device, a filter made of a fine-mesh sieve material is inserted into a section of a hot runner provided for this purpose and is fixed in position, at least in the axial direction, by means of a flanged edge, whereby polymer melt can pass through the filter.

[0004] Known filter devices, such as the one mentioned as an example, can, due to their inadequate design, lead to uneven filtration, an increased risk of leakage, and more difficult cleaning and maintenance. In particular, filters of the type mentioned, consisting of fine-mesh screen material, can cause unnecessarily high flow resistance and unnecessarily high shear forces.

[0005] The object of the present invention was to overcome the disadvantages of the prior art and to provide a filter device by means of which the disadvantages of known filter devices are overcome.

[0006] This task is solved by a filter device according to the claims.

[0007] The filter device according to the invention for separating impurities from a polymer melt in a hot runner tool or an injection molding machine during flow through the filter device, which can be fixed in position within a pipe, in particular within a line or a flow chamber, in a flow direction, comprises a filter element with a central axis that can be aligned along the flow direction and with a first end region and a second end region opposite the first end region in the direction of the central axis, wherein a wall of the filter element comprises a first wall section s designed as a hollow truncated cone, in particular as a hollow and convex truncated cone or as a hollow cone or as a hollow and convex cone, in particular dome-shaped, and the filter element is perforated by means of openings through the wall.wherein an outer space can be fluidically coupled to an inner space by means of the openings, characterized in that the filter device is jacketless and designed with a first collar coupled to the filter element in the first end region and with a second collar coupled to the filter element in the second end region, so that the filter device can be axially fixed in position within the pipe, in particular within the pipe in the radial direction and in the flow direction, by means of the first collar and / or the second collar.

[0008] In this context, the term "without a casing" means that the filter element, with its wall and any openings provided therein, is not surrounded by any casing or surface, such as a hollow cylindrical one, that can be attributed to the filter device. However, a channel or pipe in which the filter device can be positioned or fixed does form a casing, but this casing is always part of the channel or pipe, so that the filter device itself is designed without a casing.

[0009] A collar is further understood to be a cuff-like component of the filter device, which preferably includes a support surface for radial positioning and, in particular, also a further support surface for axial positioning and / or positional fixation within a channel or pipe. Such a collar can, for example, be designed like a sliding bearing surface or like a flanged edge of the wall.

[0010] In any case, it is advantageous that the filter device according to the invention, and in particular the filter element, can be easily and cost-effectively cleaned of contaminants, which enables the reusability of the filter device and improves its economic efficiency. The filter device according to the invention is also improved during the manufacturing process and can be produced with a higher quality than known filter devices of this type, since the filter element is accessible from multiple sides for processing or finishing steps, such as surface treatment, during the manufacture of the filter device. Consequently, novel or alternative manufacturing processes for the basic form of the filter device or the filter element, such as 3D printing of these parts, are also possible.Furthermore, it is worth mentioning and advantageous that, due to its specific design, the filter device according to the invention has a larger surface area of ​​the filter element than a filter device with a jacketed filter element, which, with a constant channel diameter of a pipe in which the filter device is positioned for the filtration of a polymer melt, results in a lower pressure loss or back pressure of the filter device and thus improves its economic efficiency in use.

[0011] In particular, the provision of the first and second flanges improves or advantageously ensures the precise positioning of the filter device and thus uniform filtration, a reduced risk of leakage and easier installation and removal of the filter device.

[0012] Furthermore, it can be advantageous for the filter element to include a second wall section formed opposite a truncated cone apex of the first wall section and adjoining the first wall section, wherein the second wall section is hollow cylindrical. This allows contaminants to accumulate in a simple and effective manner over an extended service life of the filter device, corresponding to the intended longitudinal extent of the second wall section, before the filter device loses its filtering effect or becomes completely unusable. Depending on the flow direction through the filter device, the external space can then also be provided as a buffer for contaminants, depending on the axial longitudinal extent of this space resulting from the axial extent of the second wall section.A preferred flow direction can therefore be from the outside to the interior of the filter device. However, the reverse flow direction for polymer melt is also possible.

[0013] In this sense, it is therefore preferable for the second wall section to be located downstream of the first wall section in the direction of polymer melt flow. Since, due to this flow direction, contaminants accumulate predominantly or even exclusively in the outer area of ​​the filter device, the removal of these contaminants from the filter device is particularly advantageous and facilitated by the filter device's jacketless design. This allows for the use of a wide variety of, and above all, very economical cleaning processes and methods. In any case, this also makes the filter device reusable.

[0014] Furthermore, the second collar can be designed as a hollow cylinder with a central flow opening for the polymer melt and is coupled to the filter element in the region of a truncated cone tip of the first wall section from the cut by means of webs, preferably three webs. In synergistic interaction with the inventive design of the first wall section of the filter element, this ensures that the positioning of the filter device in a hot runner provided for this purpose is precise and that the flow situation or flowability through the filter element is only minimally affected, which is advantageous with regard to uniform or homogeneous filtration and low flow resistance of the filter device.In particular, the design of the wall in the first wall section s as a hollow and dome-like truncated cone in conjunction with the narrowing of the flow channel by the webs is advantageous in order to avoid excessively accelerated flow of the polymer melt in this area and thus heterogeneous filtration of the same, or in the worst case even cavitation in the area of ​​this constriction.

[0015] In any case, in this context or alternatively, the second collar can be designed as a segmented structure, for example, consisting of hollow cylinder segments with openings between them. Specifically, each hollow cylinder segment can be coupled or connected to a web. This allows the flow cross-section for the polymer melt to be increased and the flow guidance to be positively influenced.

[0016] Another advantageous design is one in which the webs are configured as flow-guiding elements, whereby a directional vector component in the circumferential direction of the wall, in particular a swirl, specifically a clockwise swirl relative to the flow direction, can be imparted to the polymer melt by means of these flow-guiding elements. This further, and potentially advantageous, measure allows the filter device to easily achieve mixing of the polymer melt, in addition to its primary filtering effect. This measure should also be considered in conjunction with the possible configurations of the openings described below.In this context, it can be particularly advantageous, for example, if the polymer melt is given a clockwise swirl by means of the baffles as it flows through the filter device. This clockwise swirl can be selectively absorbed by openings that rotate clockwise (i.e., in the same direction) relative to the flow direction, in order to influence the flow resistance of the filter device, or counteracted by openings that rotate counterclockwise (i.e., in the same direction) relative to the flow direction, in order to achieve a correspondingly enhanced mixing of the polymer melt while simultaneously increasing the flow resistance. In any case, such flow-guiding elements can also be advantageous in that they can neutralize any swirl that may have arisen in the channel upstream of the filter device in the flow direction, so that the filter element can be predominantly permeated by a flow of the polymer melt directed in the flow direction.

[0017] According to a further development, the first collar can be radially projecting or protruding relative to the wall in the central axis, with additional openings extending from a projecting surface. These openings allow the outer space to be fluidically coupled to the inner space. The projecting collar creates the outer space in which contaminants can be deposited. Furthermore, the additional row of openings prevents the formation of dead zones or stagnant flow areas in the polymer melt within the first collar. This further improves or enhances the aforementioned beneficial effects.

[0018] Furthermore, it can be advantageous for the first collar to have a first circumferential surface located radially outside the central axis, and for the second collar to have a second circumferential surface located radially outside the central axis, wherein the first circumferential surface and the second circumferential surface are each designed as a centering surface, in particular as a segment of a common, fictitious cylindrical surface, specifically concentrically. This easily prevents the filter device from tilting within the channel or pipe, thus avoiding inhomogeneous flow conditions, flow dead spots, and consequently, undesirable material deposits.

[0019] Alternatively or additionally, it can be provided that, instead of the first collar and the second collar, bearing elements are provided in the direction of the central axis, preferably three bearing elements distributed in the circumferential direction, and wherein the bearing elements each have a bearing surface in order to be able to radially position the filter device in a channel or pipe provided for this purpose, wherein the bearing surfaces are specifically designed as a partial section of a cylindrical surface, but in any case are at least partially form-complementary to an inner surface of a channel.

[0020] Furthermore, it can be provided that the openings each have a bore axis, wherein each bore axis has a first inclination angle relative to a normal plane of the central axis, from a first inclination angle range of 0° to 90°, specifically 30° to 60°, and particularly 45°, wherein each opening is preferably inclined in the flow direction, and wherein, particularly in the region of a truncated cone apex of the first wall s from the cut, an additional central opening extending along the central axis is formed. The inclination of the openings primarily allows for an improved surface finish of the wall in the overhangs. The first inclination angle can be selected according to the radial extent of the outer and inner regions, which must also be taken into account in connection with the absolute extent of an outer diameter of the filter device.For example, if the radial extent of the outer area is relatively larger than that of the inner area, a first inclination angle from the range of 0° to 90° can be selected. If the radial extent of the outer area is relatively smaller than that of the inner area, the first inclination angle from the range of 30° to 60° can be selected to achieve advantageous filtration and the lowest possible flow resistance of the filter device. Particularly when the volume of the outer area is balanced with that of the inner area, a first inclination angle of 45° may be advantageous. In any case, it is not intended that the openings be designed such that the direction of any bore axis has a component opposite to the flow direction, which would, for example, result in a first inclination angle greater than 90°.

[0021] In this context, it can be advantageous if each bore axis lies in the same plane as the central axis. This would advantageously result in a swirl-free flow through the filter element. According to a particular embodiment, a radial plane is defined for each opening, wherein the radial plane is oriented perpendicular to the normal plane and the central axis lies in the radial plane. Each bore axis has an intersection with the radial plane of the opening and a second angle of inclination relative to the radial plane, ranging from 0° to 30°, particularly 5° to 15°. Specifically, the openings are inclined clockwise relative to the flow direction. This allows a swirl of the polymer melt flow to be created by the openings through the wall of the filter element.Depending on the design of the webs, the previously described advantageous effects can be achieved. For example, in conjunction with a clockwise flow guidance of the webs, a directional vector component of the polymer flow can be generated in the circumferential direction, thus inducing a swirl in the polymer flow. This can positively influence both the filtration and the mixing of the polymer flow. It can also have a beneficial effect on downstream components of a hot runner mold in the flow direction of the filter device.

[0022] According to an advantageous further development, it can be provided that each bore axis of a respective penetration through the wall, particularly exclusively in the first wall section and / or in the second wall section, has an identical angular position relative to a respective tangential plane attributable to the respective bore. This particular design results in an advantageous flow situation through the filter element.

[0023] Alternatively, it can be advantageous if the first angle of inclination of successive openings in the flow direction is unequal, particularly decreasing in the flow direction. This specific design of the openings allows for consideration of the varying volume of the outer and inner areas in the flow direction, thus optimizing the filter effect and minimizing flow resistance. In particular, this allows for consideration of the boundary layer thickness of the polymer melt flow and preferably achieves effective suction of the polymer melt's boundary layer.

[0024] Another advantageous design allows for the second angle of inclination of successive openings to be unequal, particularly decreasing in the flow direction. This addresses the aspects of potentially imparting a swirl or achieving a desirable swirl-free flow. Thus, a second angle of inclination of the opening bore axes that varies along the axial extent of the filter device advantageously allows for consideration of the varying volumes of the outer and inner regions in the flow direction.

[0025] Furthermore, it can be provided that each penetration has rounded surfaces at its inlet and outlet, or that the bore inlets and outlets have rounded radii. This prevents excessive abrasion in the penetrations and in the inlet and outlet areas of the penetrations, and additionally counteracts cavitation and increased flow resistance.

[0026] According to a further development, it is possible for the filter element to have a conical element in the region of a truncated cone tip of the first wall section, with a first conical section projecting or protruding conically from the wall in the direction of flow, wherein the conical element has a conical axis aligned along the central axis, specifically a rounded first tip in the first conical section, and is particularly designed without a through-hole. In this context, it can also be advantageous if the conical element has a second conical section projecting conically from the wall in the opposite direction of flow, particularly with a rounded second tip.On the one hand, the conical element prevents dead zones in the flow, thus counteracting the agglomeration of contaminants or even the polymer melt itself, and consequently a negative impact on filtration and flow resistance. On the other hand, the inclusion of the conical element, and in particular the second conical section, facilitates the manufacturing of the filter device. The second conical section can, for example, extend into the central flow opening of the second coil. This also improves the post-processing of the filter element and facilitates surface treatment.

[0027] Furthermore, it can be advantageous for the filter device to be designed as a single piece, which primarily has a positive effect on the stability of the filter device itself. For a better understanding of the invention, it is explained in more detail with reference to the following figures.

[0028] They each show, in a highly simplified, schematic representation:

[0029] Fig. 1 shows a possible first embodiment of the filter device;

[0030] Fig. 2 shows a sectional view of the first embodiment of the filter device;

[0031] Fig. 3 shows a section of a sectional view of a possible second embodiment of the filter device; and

[0032] Fig. 4 shows a sectional view of a possible further embodiment of the filter device.

[0033] It should be noted at the outset that in the differently described embodiments, identical parts are provided with the same reference numerals or component designations, and the disclosures contained in the entire description can be applied analogously to identical parts with the same reference numerals or component designations. Furthermore, the orientation designations chosen in the description, such as top, bottom, side, etc., refer to the figure directly described and illustrated, and these orientation designations must be applied analogously to the new position if the orientation changes.

[0034] Figures 1 and 2 show a possible first embodiment of the filter device 1 in a highly simplified, schematic representation, with Figure 2 showing a sectional view of the possible first embodiment of the filter device 1. The filter device 1 is suitable for separating impurities from a polymer melt and can be inserted, positioned, or used for this purpose in a hot runner tool or an injection molding machine. In particular, the filter device 1 can be positioned or fixed in a position for filtering the polymer melt in a pipe, a conduit, or a flow chamber, whereby the polymer melt can pass through the filter device 1 and thus be filtered.

[0035] The filter device 1 comprises a filter element 2 with a central axis 3 and with a first end region 4 and a second end region 5 opposite the first end region 4 in the direction of the central axis 3. The polymer melt flowing through the tube or channel of a hot runner tool has a flow direction. Preferably, the central axis 3 is aligned with this flow direction, and the filter element 2 is specifically designed to be rotationally symmetrical. Alternatively, however, an embodiment of the filter device 1 is also conceivable which is not rotationally symmetrical, but rather has a corresponding or shape-complementary filter cross-section corresponding to the cross-section of a channel in which the filter device 1 can be positioned for filtering polymer melt.

[0036] The filter element 2 has a wall 6, the wall 6 being perforated by means of openings 7, wherein an outer space 8 can be fluidically coupled to an inner space 9 by means of the openings 7, so that the polymer melt can flow from outer space 8 to inner space 9 or vice versa. Preferably, but not limited to, the filter device 1 is traversed from the second end region 5 of the filter element 2 to the first end region 4 of the filter element 2.

[0037] To ensure an optimal flow rate of the polymer stream through the filter element 2, the filter element 2 is designed in a first wall section 12 as a hollow truncated cone, specifically as a hollow and convex truncated cone or as a hollow cone, or as a hollow and convex cone, particularly dome-shaped, with a truncated cone apex. In this context, it can also be provided that the filter element 2 comprises a second wall s formed opposite a truncated cone apex 13 of the first wall s from section 14 and adjoining the first wall section 12, wherein the second wall section 14 is designed as a hollow cylinder.

[0038] In particular, the previously described preferred flow direction or flow direction with polymer melt offers the advantage that the filter device 1 can have a particularly long service life, since in the area of ​​the second wall section 14, contaminants filtered from the polymer melt can accumulate over a longer period of time, before the filter element 2 is completely covered with contaminants and needs to be cleaned or replaced.

[0039] In any case, the filter device 1 is jacketless and is designed with a first collar 10 coupled to the filter element 2 at the first end region 4 and with a second collar 11 coupled to the filter element 2 at the second end region 5, such that the filter device 1 can be positioned or fixed radially and axially in the flow direction within the pipe by means of the first collar 10 and / or the second collar 11. In conjunction with the preferred flow direction of the filter device 1, this offers the advantage that contaminants which have been prevented from flowing from the outer chamber 8 into the inner chamber 9 by the filter element 2 and have accumulated in the outer chamber 8 can be easily removed from the filter element 2 and from the filter device 1 by milling, brushing, washing, backwashing, burning in a pyrolysis oven, or shaking, so that the filter device 1 can be easily reprocessed and thus reused.In order to fulfill this purpose or to achieve this effect, it is preferably necessary to provide that the second wall section 14 is located downstream of the first wall section 12 in the direction of flow of the polymer melt, so that subsequently the filter element 2 is also permeated by polymer melt from the outer space 8 towards the inner space 9 through the openings 7.

[0040] In order to ensure a positionally stable bearing or position fixation of the filter device 1 in a pipe or line of a hot runner tool, it can also be provided that the second collar 11 is designed in a hollow cylindrical shape with a central flow opening 15 for the polymer melt and is coupled to the filter element 2, in particular in the area of ​​a truncated cone tip 13 of the first wall section 12, by means of webs 16, preferably by means of three webs 16, in a positionally fixed manner.Furthermore, in this context, it can be provided that the first collar 10 has a first circumferential surface 17 located radially outside the central axis 3, and the second collar 11 has a second circumferential surface 18 located radially outside the central axis 3, wherein the first circumferential surface 17 and the second circumferential surface 18 are each designed as a centering surface, in particular as a section of a common, fictitious cylindrical surface, specifically concentrically. This enables a positionally stable mounting or position fixing of the filter device 1.

[0041] To further improve the positioning or mounting of the filter device 1, it can also be provided that the first collar 10 is designed to project or protrude relative to the wall 6 in radial direction 19 with respect to the central axis 3, wherein further openings 21 are formed starting from a projection surface 20, wherein the outer space 8 can be fluidically coupled to the inner space 9 by means of the further openings 21 and vice versa, as can be seen from a combination of Fig. 1 and Fig. 2.

[0042] The openings 7 and the webs 16 can play a crucial role in the filtering effect of the filter device 1, whereby, for example, not only the mean diameters of the openings 7 are relevant as basic parameters for the filtering effect. Thus, by appropriately designing these components of the filter device 1, the flow of the polymer melt can also be influenced, in addition to the pure filtering of the polymer melt. This will be explained below with reference to the sectional views shown in Figs. 2, 3, and 4, where Fig. 3 shows a sectional view of a possible second embodiment of the filter device 1 and Fig. 4 shows a possible further embodiment of the filter device 1.

[0043] In this sense, it can be provided, for example, that the webs 16 are designed as flow-guiding elements 22, wherein a direction s vector component in the circumferential direction of the wall 6, in particular a swirl, specifically a right-hand swirl relative to the flow direction, can be imprinted on the polymer melt by means of the flow-guiding elements 22. To illustrate this and the following description in more detail, a preferred flow direction 23 is shown in Fig. 2 and Fig. 3.

[0044] Each of the openings 7 naturally has a bore axis 24. Regarding the possible configurations of the openings 7, it can be provided that each bore axis 24 has a first inclination angle 26 relative to a normal plane 25 of the central axis 3, within a first inclination angle range of 0° to 90°, specifically 30° to 60°, and particularly 45°, wherein each opening 7 is preferably inclined in the flow direction, i.e., in the direction of the preferred flow direction 23. In particular, and as shown in Fig. 2, it can also be provided that an additional central opening 27 extending along the central axis 3 is formed in the region of the truncated cone apex 13 of the first wall s from section 12.

[0045] Alternatively, and as illustrated in Fig. 3, the filter element 2 can also have a conical element 28 in the region of a truncated cone tip 13 of the first wall section 12. This conical element 28 has a first cone section 29 projecting conically from the wall 6 in the direction of the flow direction, particularly in the direction of the preferred flow direction 23. The conical element 28 has a cone axis 30 aligned along the central axis 3, specifically a rounded first tip 31 in the first cone section 29, and is particularly free of any opening. However, it is not mandatory for the conical element 28 to be free of any opening. Thus, an embodiment of the filter device 1 is also conceivable in which the conical element 28 can have a central opening, as shown for the possible first embodiment of the filter device 1 in Fig. 2.In this context, it may also be provided that the cone element 28 has a second cone 32, projecting conically from the wall 6 in the direction opposite to the flow direction, in particular with a rounded second tip 33. This advantageously influences the flow conditions, possibly also in conjunction with a special design of the webs 16, of the filter device 1.

[0046] With regard to the design options of the openings 7, it can also be provided that a respective bore axis 24 lies in a common plane with the central axis 3. This ensures a swirl-free flow through the filter device 1 or even reduces swirl, which may be necessary after curves or bends in the routing of the hot runner tool.

[0047] Alternatively, and as shown in Fig. 4, it can also be provided that a respective radial plane 34 is defined for each opening 7, wherein the radial plane 34 is oriented normal to the normal plane 25 and the central axis 3 lies in the radial plane 34, wherein a respective bore axis 24 has an intersection 35 with the respective radial plane 34 of an opening 7 and a second inclination angle 36 relative to the respective radial plane 34 from a second inclination angle range comprising 0° to 30°, in particular 5° to 15°, wherein the openings 7 are specifically inclined clockwise relative to the flow direction. By definition, a respective opening 7 can thus have an inclination in the circumferential direction of the wall 6.This allows the polymer melt to be given a swirl as it flows through the openings 7, or, with appropriate design of the second inclination angle 36, to also reduce a swirl, in order to provide a swirl-free and thus uniform flow of the polymer melt from the interior 9 onwards in accordance with the preferred flow direction 23 for further processing.In connection with the previously described possible configurations of the openings 7, it may also be provided that each bore axis 24 of a respective opening through the wall 6, in particular exclusively in the first wall section 12 and / or in the second wall section 14, has an identical angular position relative to a respective tangential plane attributable to the respective bore, wherein the respective angular position is to be understood as a respective combination of the first inclination angle 26 and the second inclination angle 36 for an opening 7 with respect to its bore axis 24.

[0048] Alternatively, the openings 7 can also be provided to have different angular positions. In particular, it can also be advantageous if the angular positions of two successive openings 7 in the flow direction or in the direction of the preferred flow direction 23 are different, so that a gradual change in the angular position of the respective downstream bore axes 24 can be provided in the direction of the preferred flow direction 23. In this way, for example, a desired mixing or thorough blending of the polymer melt can be achieved, or a swirl of the polymer melt flow can be imposed, reduced, or equalized. In this context, it can therefore be provided that the first angle of inclination 26 of successive openings 7 in the flow direction or in the direction of the preferred flow direction 23 is different.The angle of inclination of subsequent openings 7 is not equal, in particular decreasing in the flow direction. Thus, it can also be provided that the second angle of inclination 36 of subsequent openings 7 is not equal in the flow direction or in the direction of the preferred flow direction 23, in particular decreasing in the flow direction.

[0049] Finally, it is also worth mentioning that the filter device 1 is preferably designed in one piece, since the filter device 1 can be manufactured, for example, and advantageously, by means of 3D printing, casting processes or similar processes.

[0050] Finally, it should be mentioned that the same reference numerals and component designations were used for the possible embodiments of the filter device 1 shown in Figures 1 and 2, as well as in Figures 3 and 4, in order to avoid unnecessary repetition. In any case, the preceding description applies analogously to both embodiments.

[0051] The exemplary embodiments show possible embodiment variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiment variants, but rather various combinations of the individual embodiment variants are also possible and this possibility of variation lies within the skill of the person skilled in this technical field due to the teaching on technical action by the present invention.

[0052] The scope of protection is defined by the claims. However, the description and drawings must be consulted for the interpretation of the claims. Individual features or combinations of features from the different embodiments shown and described can, in themselves, represent independent inventive solutions. The problem underlying these independent inventive solutions can be found in the description.

[0053] All references to value ranges in this description are to be understood as encompassing any and all sub-ranges thereof, e.g., the reference 1 to 10 is to be understood as including all sub-ranges, starting from the lower limit 1 and the upper limit 10, i.e., all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g., 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0054] For the sake of clarity, it should be noted that, for better understanding of the structure, some elements have been shown not to scale and / or enlarged and / or reduced in size. Reference symbols list

[0055] Filter device 32 Second cone section

[0056] Filter element 33 Second tip

[0057] Central axis 34 Radial plane

[0058] First end area 35 intersection point

[0059] Second end area 36 Second tilt angle

[0060] wall

[0061] Breakthroughs

[0062] Outdoor space

[0063] interior

[0064] First Federation

[0065] Second Alliance

[0066] First wall section cut off

[0067] truncated cone tip

[0068] Second wall s cut off

[0069] Central flow breakthrough

[0070] web

[0071] First circumferential surface

[0072] Second circumferential area

[0073] radial direction

[0074] Executive area

[0075] Further breakthroughs

[0076] Flow guide element

[0077] Preferred flow direction

[0078] Bore axis

[0079] Normal plane

[0080] First tilt angle

[0081] Central breakthrough

[0082] cone element

[0083] First cone section

[0084] Conical axle

[0085] First top

Claims

P a t e n t a n s p r ü c h e 1. Filter device (1) for separating impurities from a polymer melt in a hot runner tool as the flow passes through the filter device (1), which is positionally fixable within a pipe, in particular within a line or flow chamber, in a flow direction, comprising a filter element (2) with a central axis (3) alignable along the flow direction and with a first end region (4) and a second end region (5) opposite the first end region (4) in the direction of the central axis (3), wherein a wall (6) of the filter element (2) comprises a first wall section (12) designed as a hollow truncated cone and the filter element (2) is perforated by means of openings (7) through the wall (6), wherein an outer space (8) can be fluidically coupled to an inner space (9) by means of the openings (7), characterized in that the filter device (1) is jacketless and with aThe filter device (1) is formed in the first end region (4) with a first collar (10) coupled to the filter element (2) and with a second collar (11) coupled to the filter element (2) in the second end region (5), so that the filter device (1) can be axially fixed in position within the pipe and in the direction of flow by means of the first collar (10) and / or the second collar (11).

2. Filter device (1) according to claim 1, characterized in that the filter element (2) comprises a second wall section (14) of the wall (6) opposite a truncated cone tip (13) of the first wall section (14) and adjoining the first wall section (12), wherein the second wall section (14) is formed in a hollow cylindrical shape.

3. Filter device (1) according to one of the preceding claims, characterized in that the second wall section (14) is located downstream of the first wall section (12) in the flow direction of the polymer melt.

4. Filter device (1) according to one of the preceding claims, characterized in that the second collar (11) is designed in a hollow cylindrical shape with a central flow opening (15) for the polymer melt and is connected by means of webs (16), preferably by means of three bridges (16), with the filter element (2), in particular in the area of ​​a truncated cone tip (13) of the first wall section (12), is coupled in a positionally fixed manner.

5. Filter device (1) according to claim 4, characterized in that the webs (16) are designed as flow guide elements (22), wherein a direction vector component in the circumferential direction of the wall (6), in particular a swirl, specifically a right-hand swirl relative to the flow direction, can be imprinted on the polymer melt by means of the flow guide elements (22).

6. Filter device (1) according to one of the preceding claims, characterized in that the first collar (10) is formed projecting or protruding relative to the wall (6) in the radial direction (19) with respect to the central axis (3), wherein further openings (21) are formed starting from a projection surface (20), wherein the outer space (8) can be fluidically coupled to the inner space (9) by means of the further openings (21).

7. Filter device (1) according to one of the preceding claims, characterized in that the first collar (10) has a first circumferential surface (17) located radially outside the central axis (3) and the second collar (11) has a second circumferential surface (18) located radially outside the central axis (3), wherein the first circumferential surface (17) and the second circumferential surface (18) are each designed as a centering surface, in particular each as a partial section of a common fictitious cylindrical surface, specifically concentrically.

8. Filter device (1) according to one of the preceding claims, characterized in that the openings (7) each have a bore axis (24), wherein each bore axis (24) has a first inclination angle (26) relative to a normal plane (25) of the central axis (3), from a first inclination angle range comprising 0° to 90°, in particular comprising 30° to 60°, in particular 45°, wherein each opening (7) is preferably inclined in the flow direction, and wherein in particular in the region of a truncated cone tip (13) of the first wall section (12) an additional central opening (27) extending along the central axis (3) is formed.

9. Filter device (1) according to claim 8, characterized in that a respective bore axis (24) lies in a respective common plane with the central axis (3).

10. Filter device (1) according to claim 8, characterized in that a respective radial plane (34) is defined for each opening (7), wherein the radial planes (34) are aligned normal to the normal plane (25) and the central axis (3) lies in the radial plane (34), wherein a respective bore axis (24) has an intersection point (35) with the respective radial plane (34) of an opening (7) and a second inclination angle (36) relative to the respective radial plane (34) from a second inclination angle range comprising 0° to 30°, in particular 5° to 15°, wherein the openings (7) are in particular inclined clockwise relative to the flow direction.

11. Filter device (1) according to one of claims 8 to 10, characterized in that each bore axis (24) of a respective opening through the wall (6), in particular exclusively in the first wall section (12) and / or in the second wall section (14), has an identical angular position relative to a respective tangential plane attributable to the respective bore.

12. Filter device (1) according to one of claims 8 to 10, characterized in that the first inclination angle (26) of successive openings (7) in the flow direction is unequal, in particular decreasing in the flow direction.

13. Filter device (1) according to one of claims 10 or 11, characterized in that the second inclination angle (36) of successive openings (7) in the flow direction is unequal, in particular decreasing in the flow direction.

14. Filter device (1) according to one of the preceding claims, characterized in that the filter element (2) has a conical element (28) in the region of a truncated cone tip (13) of the first wall section (12) with a first conical section (29) projecting or extending conically from the wall (6) in the direction of the flow direction, wherein the conical element (28) has a surface aligned along the central axis (3). has a cone axis (30), in particular a rounded first tip (31) in the first cone section (29) and is in particular designed without a breakthrough.

15. Filter device (1) according to claim 14, characterized in that the cone element (28) has a second cone section (32) projecting from the wall (6) in a cone-shaped manner in the direction opposite to the flow direction, in particular with a rounded second tip (33).

16. Filter device (1) according to one of the preceding claims, characterized in that the filter device (1) is formed in one piece.

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