FILTER UNIT FOR EXTRUDER ASSEMBLY, FILTER APPARATUS AND CORRESPONDING FILTER CHANGE APPARATUS AND METHOD FOR MANUFACTURING SUCH FILTER UNIT - Patent application

Abstract

To provide a filter unit for an extruder assembly.SOLUTION: A filter unit has a support body (102) which has a hollow cylindrical wall section (104) and a base section (106) connected to the hollow cylindrical wall section, where the support body (102) has a center longitudinal axis (108) and defines an internal space (110); and the hollow cylindrical wall section (104) has a plurality of through openings (112) opened to the internal space (110), and has an outlet opening (100) formed for a molten plastic on a side opposite to the base section (106). The filter unit also has a movable element (116) which substantially moves the molten plastic entering into the internal space (110) in a direction of the center longitudinal axis (108), especially, through the through opening (112), wherein the movable element (116) and the support body (102) are constituted and / or manufactured into a single piece.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a filter unit for an extruder assembly. The present invention additionally relates to a filter device for an extruder assembly and a corresponding filter replacement device. The present invention further relates to a method for manufacturing such a filter unit. [Background technology]

[0002] Typically, molten plastics, especially in the polyolefin range, are passed through a screen changer after the processing section or extrusion to filter out contaminants prior to pelletization. In the screen changer, a filter device is used with a filter element holding plate and a number of support cages with filter elements.

[0003] For example, a filter device for an extruder is known from US Pat. No. 5,399,633, which comprises an elongated screen and a retaining plate for the screen with bores arranged perpendicular to the flow direction of the molten plastic. The screen has the shape of a hollow cylinder open at one end and consists of an outer support cage made of wire and having a flange at its open end for attachment to the retaining plate, and an inner screen cage made of filter fabric and further provided with a flange for attachment to the support cage.

[0004] However, the known support cages have the disadvantages that, on the one hand, they exhibit high pressure losses and, on the other hand, they are poorly stable or have insufficient strength during operation. In particular, when moving or replacing the support cage, the latter is subjected to high bending loads due to its low wall thickness. This can lead to bending or breaking of the support cage. Furthermore, the known filter units cause a considerable drop in the pressure or differential pressure of the molten plastic, so that the throughput of the molten plastic is limited by the filter device. In addition, deposits can form on the inside of the support cage, which has a negative effect on the flow of the molten plastic. Furthermore, cleaning of the current support cages, for example by pyrolysis, is very time-consuming and there is a risk that individual components can become distorted or separated during subsequent operation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] DE2119545 Summary of the Invention

[0006] A basic object of the present invention is to provide a structural and / or functional improvement to a filter unit of the aforementioned type. An object of the present invention is also to provide a structural and / or functional improvement to a filter device of the aforementioned type and to a corresponding filter changing device. Furthermore, an object of the present invention is to provide a functional improvement to the aforementioned method for producing such a filter unit.

[0007] In particular, it is an object of the present invention to provide a filter unit, a filter device and a filter replacement device that can reduce or eliminate problems identified in connection with the prior art.

[0008] The object is achieved by a filter unit having the features of claim 1. Additionally, the object is achieved by a filter device having the features of claim 11 and by a filter changing device having the features of claim 12. Furthermore, the object is achieved by a method having the features of claim 13. Advantageous embodiments and / or developments are the subject matter of the dependent claims.

[0009] The filter unit can be or can be configured for an extruder assembly and / or a filter device and / or a filter changer. The filter unit can be configured or intended for filtering molten plastic.

[0010] The filter unit may have a support body. The support body may have a wall section in the form of a hollow cylinder. The support body may have a base section. The base section may be joined to the wall section. The support body may have and / or define a central longitudinal axis. The central longitudinal axis may in particular be an axis of symmetry of the support body. The central longitudinal axis may extend in the longitudinal direction of the support body. The support body may in particular be rotationally symmetrical with respect to the central longitudinal axis. The support body may delimit an internal space. The wall section and / or the base section may delimit the internal space. The hollow cylindrical wall section may have a plurality of through openings opening into the internal space. The through openings may extend in a radial direction relative to the central longitudinal axis. The through openings may be evenly distributed around the circumference of the support body or its wall sections. The through openings of the wall sections opening into the internal space may all have the same diameter. The diameter of the through openings may be between 2 and 5 mm, in particular between 3 and 4 mm, for example 3.5 mm. The through openings in the wall sections can have different diameters. The wall sections can form an outlet opening for the molten plastic, in particular opposite the base section. The base section can be arranged on the upstream side of the support body. The outlet opening can be arranged on the downstream side of the support body. The support body can be formed as a hollow cylinder open at one end. The wall sections and the base section can be formed and / or produced in one piece and / or in one part, i.e. from one piece or one part.

[0011] The filter unit may have a moving element for moving the molten plastic that has entered the internal space, in particular via the through opening, in particular substantially in the direction of the central longitudinal axis. The moving element may be a displacer body or a moving body. The moving element may be a displacer section or a moving section. The moving element and the support body may be constructed and / or produced in one part and / or in one piece, i.e. from one part or one piece.

[0012] The moving element can be arranged or formed in the interior space and / or the base section. The moving element and the base section can be formed or generated from one part and / or one piece, i.e. from one piece or one part. The moving element can be arranged on the upstream side of the support body. The moving element can be arranged on the side of the base section facing the interior space. The moving element can extend from the base section to the interior space. The moving element can have a base surface. The base surface can be and / or be defined by the base section. The moving element can be arranged or configured to be concentric with the central longitudinal axis. The moving element can taper from the base section towards the interior space and / or towards the central longitudinal axis.

[0013] The moving element can be configured to be substantially conical and / or cone-shaped in at least a portion. The moving element can be configured to be substantially partially conical in at least a portion. The moving element can be configured to be substantially spherical or partially spherical in at least a portion. A base surface of the moving element can be formed and / or defined by a base section. The moving element can be configured to be substantially conical, conical or frusto-conical. The moving element can be configured to be substantially hemispherical.

[0014] The moving element may have a surface and / or a profile, such as a casing surface and / or a casing profile. The surface and / or profile may have one or more surface sections and / or profile sections, such as a casing surface section and / or a casing profile section. One or more of the surface sections or profile sections may taper, for example conically, in the direction of the central longitudinal axis. One or more of the surface sections or profile sections may extend and / or be oriented obliquely in the direction of the central longitudinal axis and / or at an angle to the central longitudinal axis. The angle may be a cone angle or a half cone angle. The surface and / or profile, or one or more of the surface sections or profile sections may be configured to be concentric with the central longitudinal axis. The surface and / or profile, or one or more of the surface sections or profile sections may have or define a plurality of diameters that decrease, in particular in the axial direction, i.e. in the direction of the central longitudinal axis. The surface or contour sections may extend and / or be oriented at an oblique and / or different angle relative to the central longitudinal axis. The angle of the radially outer surface or contour sections may be greater than the angle of the radially inner surface or contour sections. The angle of the surface or contour sections may decrease in the axial direction, i.e., in the direction of the central longitudinal axis. By varying the angle, the behavior of the plastic flow or the molten plastic flow and / or the rheological conditions may be influenced as desired. The angle may be between about 30° and 90°, in particular between about 50° and 88°, for example about 50.7°, 63° or 87°, relative to the central longitudinal axis.

[0015] The support body and the moving elements may be made of a substantially non-weldable steel, for example a high alloy steel, such as a hot work steel. The steel may be a high strength and / or high toughness and / or high heat resistance steel. For example, the steel may be a 1.23xx material.

[0016] The through openings can be through holes. The support body and / or its hollow cylindrical wall section can have or define an active filter area. The active filter area can be the total area of ​​all through openings or the cross-sectional area of ​​all of the through openings. The active filter area can be the number of through openings multiplied by the cross-sectional area of ​​the through openings. The through openings can all have the same bore cross-sectional area. The support body and / or its hollow cylindrical wall section can have or define, in particular, an outer casing surface. The through openings can be distributed over the entire casing surface, for example in several rows around the casing surface. The through openings can be arranged evenly distributed over the entire casing surface. The casing surface can be defined by a diameter, in particular an outer diameter, of the support body and / or its hollow cylindrical wall section. The casing surface can be defined by a length, in particular in the direction of the central longitudinal axis, of the support body and / or its hollow cylindrical wall section. The ratio of the active filter area to the casing surface of the support body, in particular the wall section of the support body, may be about 0.15 to 0.65, in particular about 0.25 to 0.5, preferably about 0.38.

[0017] The support body and / or its hollow cylindrical wall section can have or define a wall thickness or wall strength, for example measured in the radial direction. The wall thickness can be, for example, about 2 mm to 4 mm, preferably about 3 mm or 3.5 mm. The ratio of the diameter, in particular the square of the outer diameter, of the support body and / or its hollow cylindrical wall section to the length, in particular in the central longitudinal axial length, of the support body and / or its hollow cylindrical wall section can be about 5 to 20, in particular about 10 to 16, for example about 10.7 or about 15.5. The diameter, in particular the outer diameter, of the support body and / or its hollow cylindrical wall section can be about 40 mm to 70 mm, preferably about 50 mm or about 60 mm. The length of the support body and / or its hollow cylindrical wall section can be between about 200 mm and 300 mm, preferably between about 200 mm and 250 mm, for example about 230 mm. The ratio of the wall thickness of the support body, particularly the wall section of the support body, to the ratio of the square of the diameter, such as the outer diameter, of the support body, particularly the wall section of the support body, to the length of the support body, particularly in the direction of the central longitudinal axis, can be about 0.1 to 0.6, particularly about 0.2 to 0.3, preferably about 0.25.

[0018] The support body may further comprise a holding section. The holding section may be configured for mounting the filter unit on the filter support. The holding section may be formed on the downstream side of the support body. The holding section may have a thread, such as an external thread, or a detent element, such as at least one detent lug. The filter unit may have a cover element. The filter unit may have at least one filter element. The cover element may be configured to hold and / or fix the at least one filter element on the support body. The cover element may be securely connected to the support body, for example in a removable manner, for example by being screwed to the base section and / or the moving element. The cover element may be configured to grip around the wall section or its casing surface. The cover element may have a diameter, such as an inner diameter, that is larger than the diameter, in particular the outer diameter, of the support body or its wall section. The at least one filter element may be arranged around the support body, in particular around the wall section or its casing surface, for example pressed or wrapped around it. The filter element may be a filter fleece or a filter fabric. The filter element may be a grid, a screen or a mesh. The filter element may comprise a plurality of filter fleeces, filter fabrics, grids and / or screens, which may for example be arranged radially above one another or behind one another. The grids and / or screens may have the same or different grid sizes and / or grid widths and / or grid holes. The grids and / or screens may be made of metal and / or plastic. The filter fleeces or filter fabrics may be made of fibres, such as plastic fibres, glass fibres, carbon fibres, natural fibres or mixtures thereof.

[0019] The filter device may be for or configured for an extruder assembly and / or a filter exchange device. The filter device may have a filter support. The filter support may be circular in cross section. The filter support may be substantially disk-shaped. The filter support may have a support central longitudinal axis. The support central longitudinal axis may extend in the conveying direction. The filter support may have a plurality of support through-openings extending in particular in the direction of the support central longitudinal axis. The first support through-openings may be arranged concentrically with respect to the support central longitudinal axis. For example, a group of six second support through-openings may be arranged along a first circle. The first circle may be arranged concentrically with respect to the support central longitudinal axis. The second support through-openings may be arranged evenly distributed along the first circle. A further group of, for example, twelve third support through-openings may be arranged along a second circle. The second circle may be arranged concentrically with respect to the support central longitudinal axis. The second circle can surround the first circle. The third support through openings can be evenly distributed and positioned along the second circle.

[0020] The filter device may have at least one, in particular a plurality of filter units. In the region of each of the support through openings, the filter units may be respectively attached and / or attachable in a removable manner to the filter support. Each of the support through openings may have a holding section configured to complement the holding section of the filter unit. Each of the holding sections of the support through openings may have a thread, such as an internal thread, configured to complement a thread, such as an external thread, of the filter unit. Each of the holding sections of the support through openings may have a structure for fixing the filter unit, which is complementary to a detent element, such as a detent lug, of the filter unit. The filter units may be arranged upstream of the filter support in the conveying direction. The filter units may all be configured identically. The filter units may be configured as above and / or as follows:

[0021] The filter changing device can be or can be configured for an extruder assembly. The filter changing device can have a housing and at least one melt channel extending into the housing. For example, the filter changing device can have two melt channels extending into the housing, each of the melt channels opening into or merging into a common channel of an upstream melt inlet and a downstream melt outlet. The at least one melt channel is configured to guide molten plastic produced in the extruder.

[0022] The filter changing device may have at least one guide bore extending transversely to the at least one melt channel and penetrating the melt channel in the housing. The at least one guide bore may extend transversely, for example substantially perpendicularly, to the conveying direction and / or may cross the at least one melt channel. The filter changing device may have at least one sliding element arranged in the at least one guide bore. The at least one sliding element may be configured as a plate or a cylinder. The filter changing device may have at least one actuating drive. The at least one sliding element may be moved transversely, for example substantially perpendicularly, to the conveying direction and / or transversely, for example substantially perpendicularly, to the at least one melt channel by the at least one actuating drive. The at least one actuating drive may be configured as hydraulic and / or electromechanical, for example.

[0023] The filter change device may have at least two filter devices arranged and / or mounted, for example in an exchangeable manner, on the at least one sliding element. The filter devices may be configured as above and / or as below. Two consecutive receiving openings may be formed in the at least one sliding element. The filter devices may be mounted and / or fixed in an exchangeable manner at the two receiving openings, respectively. The two receiving openings may be spaced apart transversely, for example substantially perpendicularly, to the conveying direction and / or transversely, for example substantially perpendicularly, to the at least one melt channel, whereby one of the respective filter devices is arranged outside the housing when the other respective filter device is arranged in the melt channel.

[0024] The extruder assembly may comprise a filter changing device. The filter changing device may be configured as above and / or as below. The extruder assembly may comprise an extruder, for example a twin screw extruder. The filter changing device may be arranged downstream in a conveying direction of the extruder. The extruder assembly may comprise a pelletizer. The pelletizer may be configured and / or intended for pelletizing the plastic material strands. The filter changing device may be arranged upstream in a conveying direction of the pelletizer.

[0025] The method can be for and / or can be used for the manufacture of a filter unit. The method can be used to manufacture the above filter units and / or the following filter units.

[0026] The method may comprise the step of generating blind holes in a particularly cylindrical steel blank, for example a substantially non-weldable steel blank. The blind holes may be made by drilling and / or milling and / or eroding and / or turning and / or another manufacturing process. The generation of blind holes may also be understood as manufacturing of blind holes. The manufacturing of blind holes, for example drilling and / or milling, may be performed along the central longitudinal axis. The drilling and / or milling of blind holes may consist of pre-drilling and / or pre-milling. The eroding or turning may consist of pre-eroding or pre-turning.

[0027] The method may comprise the step of generating a transfer element inside the blind hole, in particular on or in the blind hole bottom or blind hole base. The generation of the transfer element may be performed by drilling and / or milling and / or eroding and / or turning and / or other manufacturing methods. The generation of the transfer element may also be understood as manufacturing of the transfer element. The generation of the blind hole and the transfer element may be performed in one step or in successive steps. The drilling and / or milling may be performed in one process.

[0028] The method may comprise a step of enlarging the blind hole, in particular enlarging by machining. The blind hole may be enlarged by reaming, i.e. widening the hole outwards (reaming), and / or by drilling and / or turning. Reaming may be performed, for example, by a reamer. Drilling and / or turning may be performed, for example, by a drill rod. Turning may be performed, for example, by a turning tool. The enlargement, in particular reaming and / or drilling and / or turning, may be performed with vibration damping. Vibrations from the reamer and / or drill rod and / or turning tool may be damped. Enlarging the blind hole may comprise and / or consist of, for example, an adjustment and / or improvement of the roughness and / or quality of the surface. The enlargement of the blind hole may be performed before and / or after the generation of the moving element. Reaming and / or drilling and / or turning may be performed in one process. The blind hole may be flushed before enlarging.

[0029] The production of the moving element, for example drilling and / or milling, can be performed by a drill rod. The drill rod can include or be configured as a conical drill. The drill rod can include at least one cutting plate, such as an indexable insert. The drill rod can have 1 to 10, for example 2 to 7, in particular 3 to 5 cutting plates. It can have an even or odd number of cutting plates. The at least one cutting plate or the indexable insert can have a substantially square and / or round shape, for example a substantially square, rectangular and / or triangular shape. The drill rod or the conical drill can have at one end a geometric shape that depends on the surface and / or contour of the moving element, for example a geometric shape that is substantially complementary to the moving element. The at least one cutting plate can have a geometric shape that depends on the surface and / or contour of the moving element. The drill rod can have several cutting plates, such as indexable inserts. The number of cutting plates can depend on the surface and / or contour of the moving element. The number of cutting plates can be the same or twice the number of surface or contour sections of the moving element. The number of cutting plates can be from 1 to 10, for example from 2 to 7, in particular from 3 to 5. The cutting plates can also have and / or define the angles of the surface or contour sections.

[0030] By means of the invention pressure losses can be significantly reduced; throughput can be increased; stability and / or strength of the support body can be increased, especially during operation; the support body or its wall sections can have a smaller wall thickness compared to known support bodies; internal adhesions can be avoided and cleaning can be simplified; the process reliability of the production method can be increased; chipping evacuation and / or process times can be improved.

[0031] Exemplary embodiments of the invention are explained in more detail below with reference to the figures, which are presented by way of example in schematic form. [Brief description of the drawings]

[0032] [Figure 1] FIG. [Diagram 2] 2 is a cross-sectional view along AA of the filter unit according to FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view along line BB of the filter unit according to FIG. 1. [Figure 4] FIG. 2 is a front view of the filter unit according to FIG. 1; [Diagram 5] FIG. 5 is a partial cross-sectional view along EE of the filter unit according to FIGS. [Figure 6] Detail view of X of the filter unit according to Figs. 1 and 5. [Figure 7] FIG. [Figure 8] 8 is a side view of the filter device according to FIG. 7 . [Figure 9] Front view of the filter device according to Fig. 7; [Figure 10] FIG. 10 is a cross-sectional view along AA of the filter device according to FIGS. [Figure 11] FIG. [Figure 12] FIG. 12 is a plan view of the filter changing device according to FIG. [Figure 13] 12 is a rear view of the filter changing device according to FIG. 11 . [Figure 14] FIG. 14 is a cross-sectional view along AA of the filter changing device according to FIGS. [Figure 15] 4 is a flowchart of a method for manufacturing a filter unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] 1 to 6 show different views of a filter unit 100 configured for filtering molten plastic. The filter unit 100 comprises a support body 102 having a hollow cylindrical wall section 104 and a base section 106 connected thereto. The support body 102 has a central longitudinal axis 108 and defines an interior space 110. The hollow cylindrical wall section 104 has a plurality of through openings 112 opening into the interior space 110 and forms an outlet opening 114 for the molten plastic on the opposite side of the base section 106. The through openings 112 of the wall section 104 opening into the interior space 110 all have the same hole diameter 120. The through openings 112 are formed as through holes 112 in this exemplary embodiment.

[0034] The base section 106 is arranged on the upstream side of the support body 102 (to the right in FIG. 1 ), and the outlet opening 114 is arranged on the downstream side of the support body 102 (to the left in FIG. 1 ). A filter element, such as a filter fleece (not shown in FIGS. 1-6 ), is arranged around the wall section 104, for example pressed in. Molten plastic is forced out of the filter element and then enters the interior space 110 through the through opening 112, where the molten plastic flows to the outlet opening and leaves it again.

[0035] The ratio of the active filter area to the outer casing surface of the wall section 104 of the support body 102 is about 0.15 to 0.65, in particular about 0.25 to 0.5, preferably about 0.38. The active filter area is the total area of ​​all the through holes 112 or the cross-sectional area 118 of all the through holes 112. Thus, the active filter area can be calculated or defined by multiplying the number of through holes 112 by the cross-sectional area 118 of the through holes 112, since all the through holes 112 have the same hole diameter 120.

[0036] The ratio of the wall thickness 122 of the wall section 104 of the support body 102 to the ratio of the square of the diameter 124, such as the outer diameter 124 of the wall section 104 of the support body 102 to the length 126 in the direction of the central longitudinal axis 108 of the wall section 104 of the support body 102, is about 0.1 to 0.6, particularly about 0.2 to 0.3, and preferably about 0.25.

[0037] The filter unit 100 also includes a moving element 116 for moving the molten plastic that has entered the interior space 110 through the through opening 112 substantially in the direction of the central longitudinal axis 108. As shown in Figures 5 and 6, the moving element 116 and the support body 102 are formed in one piece and made from one piece body or one component. To make the one-piece support body 102 with the moving element 116, substantially non-weldable steels are used, in particular alloy steels such as high alloy, hot work steels.

[0038] A moving element 116 is disposed or formed within the interior space 110 and on the base section. As shown in Figure 5, the moving element 116 is substantially conical in shape, at least in cross section, with a base surface of the moving element 116 formed by the base section 106. To allow for uniform flow of the molten plastic, the moving element 116 is disposed or formed concentrically about the central longitudinal axis 108, as shown in Figures 2, 3 and 5.

[0039] The moving element 116 further comprises a casing surface 128 or casing contour 128 having a plurality of casing surface sections 130a, 130b, 130c or casing contour sections 130a, 130b, 130c that are substantially conically tapered in the direction of the central longitudinal axis 108 and extend obliquely at different angles 132a, 132b, 132c relative to the central longitudinal axis 108, the angle of the radially outer casing surface section 130a, 130b, 130c or casing contour section 130a, 130b, 130c being greater than the angle of the radially inner casing surface section 130a, 130b, 130c or casing contour section 130a, 130b, 130c. In the present exemplary embodiment according to Figures 5 and 6, the radially outer casing surface section 130c or casing contour section 130c has a larger angle 132c with respect to the central longitudinal axis 108 than the two radially further inner casing surface sections 130a, 130b or casing contour sections 130a, 130b. The radially inner casing surface section 130a or casing contour section 130a has a smaller angle 132a with respect to the central longitudinal axis 108 than the two radially further outer casing surface sections 130b, 130c or casing contour sections 130b, 130c. In this way, the casing surface or contour of the displacer element 116 is specially configured to allow optimal flow and transport of the filtered molten plastic to the outlet opening 114 in the direction of the central longitudinal axis 108. The flow behavior and rheological ratio of the molten plastic can be optimally adjusted by selecting the appropriate angles 132a, 132b, 132c, especially to prevent product build-up on the inflow side. The chip removal ability during the manufacturing process can also be improved by the appropriate selection of the angles 132a, 132b, 132c.

[0040] The support body 102 further includes a downstream retaining section 134 configured to attach the filter unit 100 to a filter support. The retaining section 134 can have, for example, an external thread complementary to a thread on the filter support (not shown in FIGS. 1-6 ) so that the support body 102 can be screwed onto the filter support.

[0041] 7-10 show various views of a filter device 200 configured for filtering molten plastics and used in a filter changer. The filter device 200 has a filter support 202 with a support central longitudinal axis 204 and, as shown in FIG. 10, a number of support through-openings 206 extending in the direction of the support central longitudinal axis 204. In the region of the support through-openings 206, the filter units 100 are respectively detachably attached to the filter support 202 and are screwed into an internal thread 208 by means of the retaining section 134 of the filter unit 100. The filter unit 100 is formed as described above and / or as follows: A filter element 210, for example a filter fleece 210, is respectively pressed into the support body 102 of the filter unit 100 and fixed to the respective wall section 104 of the support body 102 by means of a cover element 212. The cover element 212 can be screwed to the support body 102, for example to its base section 106 and / or to the moving element 116.

[0042] As shown in FIG. 9, the filter support 202 has a circular cross section. The support central longitudinal axis 204 extends parallel to the central longitudinal axis 108 of the filter unit 100 in the conveying direction, as shown in FIGS. 8 and 10. The first support through openings 206 are arranged concentrically with the support central longitudinal axis 204. A group of second support through openings 206, here six, is arranged along a first circle concentric with the support central longitudinal axis 204, the second support through openings 206 being evenly distributed along the first circle. A further group of twelve third support through openings 206, here twelve, is arranged along a second circle concentric with the support central longitudinal axis 204, the second circle surrounding the first circle. The third support through openings 206 are also evenly distributed along the second circle.

[0043] In addition, specific reference is made to Figures 1-6 and the associated descriptions.

[0044] 7-10 show different views of a filter changing device 300 for an extruder assembly. The filter changing device 300 has a housing 302 and two melt channels 304 extending within the housing 302, which open or transition into a common inlet channel 306 or outlet channel 306 at an upstream melt inlet and a downstream melt outlet, respectively. The filter changing device 300 further has two guide bores 310, each extending transversely, e.g., substantially perpendicularly, to a respective melt channel 304 and through the latter into the housing 302. The guide bores 310 also extend transversely, e.g., substantially perpendicularly, to the conveying direction.

[0045] The filter changing device 300 comprises two cylindrical sliding elements 312, which are respectively displaceably mounted in the guide bores 310. Furthermore, the filter changing device 300 comprises an actuating drive 314 configured to displace the sliding elements 312 independently of one another, e.g. transversely, e.g. substantially perpendicularly, to the conveying direction and transversely, e.g. substantially perpendicularly, to the respective melt channel 304. The at least one actuating drive 314 can be configured, for example, hydraulically and / or electromechanically.

[0046] In the present exemplary embodiment according to Figs. 11-14, the filter exchange device 300 comprises four filter devices 200. The filter devices 200 are configured as described above and / or as follows: Two filter devices 200 are arranged at a distance from each other on the slide element 312. For this purpose, two consecutive receiving openings 316 are respectively formed in the slide element 312, in which a filter device 200 is replaceably attached and / or fixed. The two receiving openings are spaced apart transversely, e.g. substantially perpendicularly, to the conveying direction and transversely, e.g. substantially perpendicularly, to the respective melt channel 304, such that one of the filter devices 200 is arranged outside the housing 302 when the respective other filter device 200 is arranged in the melt channel 304.

[0047] In addition, specific reference is made to Figures 1-10 and the associated descriptions.

[0048] FIG. 15 shows a schematic flow chart of a method for manufacturing filter unit 100.

[0049] In step S1 blind holes are drilled and / or milled in a particularly cylindrical steel blank, for example a substantially non-weldable steel blank. The drilling and / or milling of the blind holes is performed along a central longitudinal axis 108.

[0050] In step S2, the blind hole is reamed, i.e. the hole is widened outwards, for example with a reamer. Prior to reaming, the blind hole can be flushed.

[0051] In step S3, the moving element 116 is drilled or milled in the blind hole, in particular at the blind hole bottom or blind hole base. The drilling and / or milling of the moving element 116 can be performed using a drill rod. The drill rod can have or be configured as a conical drill. The drill rod can have at least one cutting plate, such as an indexable insert. The at least one cutting plate can have a geometric shape that depends on the surface and / or the contour of the moving element 116. The drill rod can include several cutting plates, such as indexable inserts. The number of cutting plates can depend on the surface and / or the contour of the moving element 116. The number of cutting plates can be the same or double the number of surface or contour sections of the moving element 116. For example, the drill rod can include 1 to 10, in particular 2 to 7, preferably 3 to 5 cutting plates. The number of cutting plates can be an even or odd number. The cutting plate may have and / or define surface or contour section angles 132a, 132b, 132c.

[0052] In addition, specific reference is made to Figures 1-14 and the associated descriptions.

[0053] The term "may" is used specifically to refer to optional features of the invention. There are therefore further developments and / or exemplary embodiments of the invention that may additionally or alternatively have the respective feature or features.

[0054] From the combinations of features disclosed herein, isolated features may be selected as appropriate and used in combination with other features to define the subject matter recited in the claims while resolving structural and / or functional relationships that may exist between the features. The order and / or number of steps in the methods may be varied. [Explanation of symbols]

[0055] 100 filter units 102 Support body 104 Wall Section 106 Bass Section 108 Central Longitudinal Axis 110 Interior Space 112 Through opening 114 Exit opening 116 Movement Elements 118 Cross-sectional area 120 pore diameter 122 wall thickness 124 Outer diameter 126 Length 128 Casing Surface / Casing Contour 130a Casing surface section / Casing contour section 130b Casing surface section / Casing contour section 130c Casing Surface Section / Casing Contour Section 132a angle 132b angle 132c angle 134 Retention Section 136 External Thread 200 Filter Device 202 Filter support part 204 Support center longitudinal axis 206 Support part through opening 208 Internal Thread 210 Filter element 212 Cover Elements 300 Filter replacement device 302 Housing 304 Melting Channel 306 Entrance Channel 308 Exit Channel 310 Guide bore 312 Slide elements 314 Actuating Drive 316 Receiving opening S1 Drilling and / or milling blind holes S2 Reaming blind holes S3 Drilling and / or milling moving elements

Claims

1. 1. A filter unit for an extruder assembly, comprising: a support body having a hollow cylindrical wall section and a base section connected thereto, the support body having a central longitudinal axis and defining an interior space, the hollow cylindrical wall section having a plurality of through openings extending into the interior space and forming an exit opening for molten plastic on an opposite side of the base section; and a moving element for moving the molten plastic in the direction of the central longitudinal axis, the moving element being configured to move the molten plastic in the internal space; the moving element and the support body are constructed and / or manufactured in one piece; Filter unit.

2. The moving element is disposed or configured in the interior space and / or on the base section; The filter unit according to claim 1 .

3. the moving element is configured, at least in some parts, to be conical and / or cone-shaped and / or partially conical and / or spherical and / or partially spherical, and / or a base surface of the moving element is formed and / or defined by the base section, The filter unit according to claim 1 .

4. The moving elements are arranged or configured to be concentric with respect to the central longitudinal axis. The filter unit according to claim 1 .

5. the moving element has a surface and / or a contour with one or more surface sections and / or contour sections, the one or more surface sections or contour sections tapering in the direction of the central longitudinal axis and / or extending obliquely relative to the central longitudinal axis; The filter unit according to claim 1 .

6. the plurality of surface or contour sections extend obliquely and / or at different angles relative to the central longitudinal axis, the angle of the radially outer surface or contour sections being greater than the angle of the radially inner surface or contour sections; The filter unit according to claim 5.

7. the through openings of the hollow cylindrical wall section opening into the interior space all have the same diameter; The filter unit according to claim 1 .

8. the support body and the moving elements are manufactured from non-weldable steel; The filter unit according to claim 1 .

9. the ratio of active filter area to the surface of the support body is about 0.15 to 0.65; The filter unit according to claim 5.

10. the ratio of the wall thickness of the support body to the ratio of the square of the diameter of the support body to the length of the support body is about 0.1 to 0.6; The filter unit according to claim 1 .

11. A filter device for an extruder assembly having a filter support having a support central longitudinal axis and a plurality of support through openings extending in the direction of said support central longitudinal axis, wherein in the region of each of said support through openings a filter unit according to any one of claims 1 to 10 is attached and / or can be attached in a removable manner to said filter support, respectively.

12. 1. A filter changing apparatus for an extruder assembly, comprising: housing; at least one melt channel extending into said housing; at least one guide bore extending transversely to and through the at least one melt channel within the housing; at least one slide element disposed in the at least one guide bore; and at least two filter devices according to claim 11 arranged at a distance from each other and / or mounted on the at least one sliding element; Filter replacement device.

13. A method for manufacturing a filter unit for an extruder assembly according to any one of claims 1 to 10, comprising the steps of: Creating blind holes in a steel blank; and generating a moving element inside the blind hole; method.

14. The creation of the blind hole and the moving element is performed in one step or in successive steps; The method of claim 13.

15. Enlarging the blind hole before and / or after generating the moving element. The method of claim 13.

16. The generation of the moving elements is carried out by a drill rod having at least one cutting plate; The method of claim 13.

17. The at least one cutting plate has a geometric shape that depends on the surface and / or the contour of the moving element.

17. The method of claim 16.

18. The drill rod has several cutting plates depending on the surface and / or the contour of the moving element; 17. The method of claim 16.

19. The drilling rod has a number of cutting plates corresponding to the number or twice the number of surface or contour sections of the moving element.

17. The method of claim 16.

20. The drill rod has 1 to 10 cutting plates.

17. The method of claim 16.

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