Title of Invention

BEARING SUPPORT FOR EXTRUDER BARREL AND EXTRUDER

Abstract

ABSTRACT Bearing support for the support of an extruder barrel, consisting of a pedestal (1) connected rigidly with a base frame (9), a support element (3), and a receiving part (5) connected rigidly with the extruder barrel (8), whereby the pedestal (1) and the support element (3) as well as the support element (3) and the receiving part (5) are respectively connected with one another by a flexible connection element, and whereby both the first as well as the second flexible connection element (2.1, 2,2, 4.1, 4.2) are embodied in such a manner that the receiving part (5) is movable horizontally essentially only in the direction of the central longitudinal axis (8,1) of the extruder barrel (8) in connection with arising loads. Moreover, an extruder, especially a large extruder for the plastics processing, is claimed, which is equipped with at least one bearing support according to the invention.

Full Text

BEARING SUPPORT FOR EXTRUDER BARREL AND EXTRUDER The invention relates to a bearing support for extruders, especially for large extruders for plastics processing, according to the preamble of the patent claim 1, The invention further relates to an extruder with at least one such bearing support according to the preamble of the patent claim 7. In large extruders, the extruder cylinder or barrel is usually secured with one end rigidly on a drive unit. The opposite end of the essentially horizontally arranged extruder barrel must be supported in order to take up the weight forces of the extruder barrel* In that regard, a bearing support serving this purpose must take up a considerable thermal expansion in the direction of the central longitudinal axis of the extruder barrel, because large extruder barrels in plastics processing comprise a length of up to 10 meters and are heated up to over 3OO°C. From that l:here arise length expansions of several centimeters in the direction of the central longitudinal axis of the extruder barrel. These length expansions must be taken up by the bearing support or bearing supports, while the extruder barrel is stationarily supported , on the mentioned drive unit. In the extruder barrel, the extruder screw driven by the drive unit is rotatably arranged coaxially to the extruder barrel. In addition to the thermal expansions in the axial direction of the extruder barrel, thermal expansions also arise perpendicularly to the central longitudinal axis of the cylinder or barrel. Vertical shiftings or displacements perpendicular to the central longitudinal axis arise due to the thermal expansion of the drive unit and of the bearing support on the side of the extruder barrel facing away from the drive. In practice it has been shown that the drive unit and the bearing support are vertically expanded approximately equally, that is to say the extruder barrel and the screw arranged therein shift upwardly and downwardly nearly parallel to one another. Therefore, the vertical shiftings or displacements have proved to be unproblematic in practice. Horizontal sliding displacements or shiftings transversely to the central longitudinal axis of the extruder barrel are caused by the accessory components or attachment parts of the extruder. On the end of the extruder barrel facing away from the drive, the extruder barrel is connected via rigid melt lines with following or subsequent stationarily arranged accessory components or attachment parts of the extrusion plant, such as for example with filters, with a melt pump, and with the extrusion nozzle. The melt lines are usually arranged horizontally and transversely to the central longitudinal axis of the extruder barrel. As a result, due to thermal expansion in the melt lines and in the stationary accessory components or attachment parts, horizontal forces arise transversely to the central longitudinal axis of the extruder barrel, which forces engage or act on the end of the extruder barrel facing away from the drive* In order that these transverse forces do not bendingly deform the extruder barrel that is rigidly secured on the drive side to the drive unit, it is known to slidably support the entire extruder with drive unit on a foundation. That is to say, the unavoidable horizontal transverse sliding displacements due to thermal expansion in the melt lines are taken up by a sliding displacement of the entire extruder. However, the sliding displacement of the entire extruder on the foundation bearing support does not take place in a friction-free manner, and due to the large mass of the extruder, exerts a considerable resistance against the displacing force, before the entire extruder is slidingly displaced on the foundation bearing support. Thereby considerable loads arise in the horizontal direction transversely to the central longitudinal axis of the extruder barrel, which again in turn can lead to the bending deformation of the extruder barrel. Bending deformations of the cylinder or barrel lead to the result that the extruder screw rubs or scrubs on the inner surface of the barrel, and that thereby the extruder screw and/or the barrel become damaged or at least strongly worn• Moreover, the extrusion conditions in the interior of the extruder barrel are disadvantageously influenced by deformations of the barrel. For the bearing support of such extruder barrels, various different embodiments of extruder supports are known. For example, in the DE 36 16 7 61 Cl, in Figure 1, a support is described that provides also a compensation in the vertical direction in addition to the horizontal length compensation. A sloping path or track, for example in the form of a ball race bed, described for this purpose permits horizontal sliding displacements transversely to the longitudinal axis of the extruder barrel and therewith bending deformations of the cylinder or barrel in this direction. Further embodiment forms of a support described in the Figures 2 to 6 of the DE 36 16 761 Cl all comprise a certain freedom of motion in the horizontal direction transverse to the cylinder or barrel longitudinal axis due to multiply movable form-fitting connections of the components. Thereby, horizontal sliding displacements transverse to the longitudinal axis of the extruder barrel are possible, and a bending deformation of the cylinder or barrel is not excluded. Due to the multiply movable form-fitting connections of the components, these embodiments of a support additionally require a high fabrication and installation or assembly effort. The object underlying the invention is to provide a bearing support for an extruder barrel, which bearing support permits a length expansions of the extruder barrel and prevents a horizontal bending deformation of the extruder barrel transversely to the central longitudinal axis of the extruder barrel. This bearing support shall be realizable with a small fabrication effort* Moreover, an extruder, especially a large extruder for the plastics processing, with the described bearing support shall be provided* The object is achieved according to the invention by means of a bearing support according to patent claim 1 and by means of an extruder according to claim 7. Further developments suitable to the purpose are defined in the dependent claims. According to the invention, the bearing support consists of at least one pedestal rigidly connected with a base frame, a support element, and a receiving part rigidly connected with the extruder cylinder, In that regard, the central longitudinal axis of the extruder barrel and the central axis of the receiving part lie essentially parallel to one another. The pedestal is connected rigidly and in a play-free manner with at least one first flexible connection element, which first connection element again in turn is connected rigidly and in a play^free manner with the support element. The support element is connected rigidly and in a play-free manner with at least one second flexible connection element, which second connection element again in turn is connected rigidly and in a play-free manner with the receiving part for the extruder barrel, The rigid and play-free connections between all essential components of the bearing support lead to the result that the flexible connection elements act as defined articulation or joint points on the support. In that regard, both flexible connection elements are embodied in such a manner that the receiving part is movable horizontally essentially only in the direction of the central longitudinal axis of the extruder barrel, and horizontal movements transversely to the central axis of the receiving part are nearly excluded. Forces in the horizontal direction transversely to the central longitudinal axis of the extruder barrel are conducted or introduced in a play-free manner into the base frame due to the rigid frictionally-engaging construction or assembly of the components of the bearing support. Further advantageous embodiments of the invention arise from the dependent claims. In preferred embodiments, either the first or the second flexible connection element is at least one bendable metal sheet or plate, or both connection elements consist of at .1 east one bendable metal sheet. The bendable metal sheet preferably has the form of a rectangular flat parallelepiped block, of which the smallest extension or dimension, namely the metal sheet thickness, is significantly smaller than the extension or dimension in the other two directions, namely the length and the width. From that there arise considerable differences in the moments of resistance of the effective cross-sectional surface areas in different directions, The dimensions and the arrangement of the at least one bendable metal sheet are selected so that the moment of resistance in the horizontal direction transversely to the central axis of the receiving part is so high that the bearing support does not become deformed in this direction due to the arising load. In contrast, the moment of resistance of the at least one bendable metal sheet in the horizontal direction along the central axis of the receiving element is so small that horizontal sliding displacements in the direction of the central axis of the receiving element and therewith in the direction of the central longitudinal axis of the extruder barrel are possible. In this manner, the length expansion of the extruder barrel is taken up by the bearing support. The rigid connections between the flexible connection elements and the components connected therewith are preferably carried out as screwed connections. Screwed connections have the advantage that they are easily again re leas able. This can be advantageously used in order to optimize the deformation behavior of the bearing support by exchanging the flexible connection elements with other flexible connection elements having other characteristics. Thus, for example, in embodiments with bendable metal sheets, the number, the thicknesses, or the material of the bendable metal sheets can be changed in order to improve the deformation behavior of the bearing support. In embodiments of the bearing support with the mentioned screwed connections, the flexible connection elements and the components connected therewith respectively comprise recesses for leading through screws. The recesses can be formed as circular or as elongated holes as well as threaded holes, or as lateral cut-ins or grooves. In that regard, elongated holes and lateral cut--ins have the advantage that the screwing connection at this location is adjustable in at least one direction, A vertical adjustability is, for example, necessary in a further preferred embodiment of the inventive bearing support, namely in an embodiment that comprises means for the height adjustment of the extruder barrel. Therewith, especially during the installation or assembly and start-up of the extruder, an advantageous vertical orientation of the extruder barrel can be achieved. Moreover, an extruder, especially a large extruder for the plastics processing, is disclosed, which is equipped with at least one bearing support according to the invention. In that regard, the extruder barrel is essentially horizontally arranged, is connected with one end rigidly with a base frame of the extruder via a drive unit/ and is supported by means of at least one bearing support according to one of the preceding claims. The base frame is movably arranged on a foundation bearing. Depending on the length and the diameter of the extruder barrel, it can be advantageous to arrange several bearing supports in various arrangements over the length of the extruder barrel* In this manner, for example, sagging bending deflections of the extruder barrel due to the force of gravity can be reduced. In that regard, the combination of at least one bearing support according to the invention with at least one conventional bearing support is also conceivable. The inventive bearing support ,is then preferably arranged close to the location of the extruder barrel at which transverse forces introduced from the outside become effective. The entire extruder with the base frame represents a rigid unit in the direction transverse to the central longitudinal axis of the extruder barrel due to the bearing support that is rigid in the lateral direction, and is movably arranged on a foundation bearing» This arrangement enables horizontal sliding displacements of the extruder in order to compensate thermal expansions in the melt lines and accessory components or attachment parts arranged horizontally transverse or obliquely relative to the central longitudinal axis of the extruder barrel, The invention and further arising advantages are explained in more detail in the following in connection with an example embodiment. In the accompanying drawings: Fig, 1: shows an extruder according to the invention with a bearing support in the side elevation view and in the top plan view. Fig, 2: shows a perspective view of a bearing support according to the invention. Fig, 3: shows a bearing support according to the invention in the front elevation view and side elevation view, and Fig. 4: shows a perspective view of a flexible connection element. An extruder consisting of a base frame 9, a drive unit 10, an extruder cylinder or barrel 8 and a bearing support 1, 3, 5 is illustrated in Fig. 1, The entire extruder is slidably displaceable on a foundation bearing 12, The extruder barrel 8 is rigidly connected with the drive unit 10. The extrusion material is supplied or fed to the drive-side end of the extruder barrel 8. The extrusion material is melted and mixed in the extruder'barrel 8, while it is transported to the side facing away from the drive by an extruder screw that is not shown, and there exits from the extruder barrel 8. On the side facing away from the drive, the extruder barrel 8 is supported on the bearing support 1, 3, 5. The bearing support is rigidly screwed onto the base frame 9• The base frame 9 is slidably displaceably supported on the foundation via the foundation bearing 12, The bearing support 1, 3, 5 takes up thermally induced length variations of the extruder barrel 8, in that the bendable metal sheets between the pedestal 1 and the support part 3, as well as the bendable metal sheets between the support element 3 and the receiving part 5 bendingly deform. That is to say, the support element 3 tips by a certain angular value in or contrary to the X-direction. Both the central longitudinal axis 8.1 of the extruder barrel 8 as well as the central axis 5.3 of the receiving part 5 are oriented in the X-direction and for example lie along a line in the illustrated embodiment. Loads in the Y-direction act on the extruder barrel 8 as soon as thermal expansions arise in the rigid melt lines 11 mounted on the side facing away from the drive. The melt lines 11 are installed essentially in the Y-direction and are stationarily secured at their end facing away from the extruder. In connection with the heat-induced expansion, the melt lines 11 transmit forces in the Y-direction via the extruder barrel 8 and the bearing support 1, 3, 5 into the base frame 9. The base frame 9 then is slidingly displaced together with the entire extruder on the foundation bearing 12, If the bearing support would permit sliding displacements in the Y-direction, then the extruder barrel 8 would be bendingly deformed before the entire extruder would be slidingly displaced on the foundation bearing 12, because the foundation bearing support 12 opposes a sliding displacement with a considerable resistance due to the high mass of the extruder• This bending deformation of the extruder barrel 8 is prevented by the bearing support that is rigid in the Y-direction, Laterally, that is to say in the Y-direction, the bearing support according to the invention permits no sliding displacement because the individual components of the bearing support 1, 3^ 5 are connected rigidly and in a play-free manner with one another, and because the flexible connection elements are nearly rigid in the Y-direction. Fig. 2 shows a bearing support according to the invention in a perspective view. It consists of a pedestal 1, which is rigidly screwed to a base frame. Two support feet 1 * 1 and 1,2 are arranged on the pedestal 1. The support element 3 forms the middle part of the bearing support, It consists of two lateral support posts 3,1 and 3.2, that are connected with one another through a stabilization plate 3.3, The stabilization plate 3.3 serves for the purpose that the bearing support is not bendingly deformed in the Y-direction, in that it connects the lateral support posts 3.1 and 3.2 rigidly with one another. Moreover, the stabilization plate 3.3 prevents a twisting or turning of the bearing support for example about the Z-axis- The receiving part 5 for the extruder barrel 8 is arranged at the upper end of the bearing support opposite the pedestal 1. It essentially consists of a lower bearing part 5.1 and an upper bearing cover or lid 5.2. The extruder barrel 8, which is not shown here^ is rigidly clamped in between the lower bearing part 5.1 and the bearing cover 5.2. The bearing cover 5,2 is rigidly screwed to the lower bearing part 5 • 1 of the receiving part 5 by means of two internal hex head or Allen screws 5.21, 5.22. Moreover, a height adjustment 6.1, 6.2 is also provided on the receiving part 5. The pedestal 1 is connected with the support element 3 via the same connection as is the support element 3 with the receiving part 5. Each one of these connections respectively consists of one bendable metal sheet 2.1, 2,2, 4.1, 4.2. Each bendable metal sheet 2.1, 2.2, 4.1, 4.2 is rigidly screwed to the respective adjoining component by means of two screws 7 and a screw block 2.11, 2.12, 4.11, 4,12. For that purpose, each screw block 2.11, 2.12, 4,11, 4.12 is provided with two internal threadings. This type of connection is completely play-free in the Y-direction and permits no sliding displacement in the Y-direction, because the bendable metal sheets comprise an enormously high moment of resistance in the Y-direction. As a result, the entire bearing support transmits loads in the Y-direction in a play-free manner and rigidly from the extruder barrel 8 onto the base frame 9, so that the extruder barrel 8 is not bendingly deformed by transverse forces - Moreover, Fig. 2 shows the means 6.1, 6.2 for the height adjustment of the bearing support, which are arranged in an identical embodiment on both sides of the bearing support. Each means 6.1, 6.2 for the height adjustment consists of a threaded bolt 6.1 and a fixing nut 6.2, The function of the height adjustment can be seen from the side view shown in section in Fig. 3, The threaded bolt 6,1 is screwed vertically through the lower bearing part 5.1, The lower end of the threaded bolt 6,1 stands upon the screw block 4.12 and further is supported via the bendable metal sheet 4.1 against the support element 3 and the pedestal 1 of the bearing support toward the bottom. The threaded bolt 6.1 can be clampingly held or secured in every position by means of the fixing nut 6.2. In order that a vertical sliding displacement is made possible, the screw holes in the lower receiving part 5,1 for the screws 7 are embodied as elongated holes. For adjusting the height of the bearing support and therewith of the extruder barrel 8, on both sides of the bearing support the fixing nut 6,2 and the two upper screws 7 are released or loosened. Subsequently, the threaded bolt 6.1 on both sides of the bearing support is screwed in or screwed out. By screwing in the threaded bolt 6.1, the receiving part 5 is lifted and therewith also the extruder barrel 8 supported therein is lifted at the corresponding location. By screwing out the threaded bolt 6.1 the receiving part 5 and with it the extruder barrel 8 are lowered. After the adjustment of the height, the fixing nut 6,2 and the screws 7 on both sides of the bearing support are tightened in order to fix the adjusted and set height of the extruder barrel 8. The left illustration in Fig. 3 shows the bearing support according to the invention with the installed extruder barrel 8 in the front elevation view. Fig. 4 shows a preferred embodiment of the flexible connection elements 2.1 and 4.1 in the form of a parallelepiped-shaped bendable metal sheet or plate. The orientation of the bendable metal sheet in the illustration, with respect to the illustrated orthogonal coordinate axes, thereby corresponds to the installation position in the bearing support according to the invention, that is to say the sheet metal thickness extends in the X-direction, the length and width of the bendable metal sheet extend in the Y- and in the Z-direction. The orientation of the bendable metal sheet and the dimensions thereof lead to the result that the bendable metal sheet opposes arising loads in the X-direction with a considerably smaller moment of resistance than in the Y- and Z-direction, The bendable metal sheets 2.1, 4.1 are embodied so that they oppose the loads in the Y-direction with such a high moment of resistance that deformations in thi.s direction are nearly excluded. The magnitude of the moment of resistance of the bendable metal sheets 2.1, 4.1 in the X-direction determines the deformation characteristic or behavior of the bearing support in the X-direction and thus in the direction of the length expansion of the extruder barrel 8. In that the moment of resistance of the bendable metal sheets 2.1, 4,1 is varied, for example in the X-direction, therefore the deformation behavior of the bearing support can be advantageously influenced. This can occur, for example, by varying the metal sheet thickness or the materials. The illustrated bendable metal sheet is provided with four circular recesses 2,13 for passing through screws 7, in order to thereby enable rigid connections to the adjoining components, Patent Claims: 1, Bearing support for the support of an extruder barrel, consisting of a pedestal (1) connected rigidly with a base frame (9), a support element (3) and a receiving part (5) connected rigidly with the extruder barrel (8), characterized in That the pedestal (1) is connected rigidly with at least one first flexible connection element (2.1, 2,2), that the first flexible connection element (2.1, 2.2) is connected rigidly with the support element (3), that the support element (3) is connected rigidly with at least one second flexible connection element (4.1, 4.2), that the second flexible connection element (4.1, 4.2) is connected rigidly with the receiving part (5), and that both the first as well as the second flexible connection element (2.1, 2.2, 4.1, 4.2) is embodied in such a manner that the receiving part (5) is movable horizontally essentially only in the direction of the central longitudinal axis (8.1) of the extruder barrel (8) in connection with arising loads. 2, Bearing support according to claim 1, characterized in that the first or the second flexible connection element (2.1, 2.2, 4.1, 4.2) consists of at least one bendable metal sheet. 3. Bearing support according to claim 1, characterized in that the first and the second flexible connection element (2,1,, 2-2, 4.1, 4.2) respectively consist of at least one bendable metal sheet. 4- Bearing support according to claim 2 or 3, characterized in that the at least one bendable metal sheet comprises a parallelepiped-shaped basic shape, whereby the thickness of the bendable metal sheet is significantly smaller than the length and than the width, so that the bendable metal sheet opposes active loads in the direction of its thickness dimension with a significantly smaller moment of resistance than in the direction of its length and width dimension, and that the bendable metal sheet is arranged in the bearing support in such a manner so that the thickness of the bendable metal sheet extends in the direction of the central longitudinal axis (8.1) of the extruder barrel (8). 5. Bearing support according to one of the claims 1 to 4> characterized in that the flexible connection elements (2.1, 2.2, 4.1, 4.2) are at least partially screwed to the neighboring components, and that the flexible connection elements (2.1, 2.2, 4,1, 4.2) and the components screwed thereto for this purpose comprise recesses for the guiding through of screws (7). 6, Bearing support according to one of the claims 1 to 5, characterized in that means for the height adjustment (6.1, 6,2) are provided on the bearing support. 7. Extruder, especially large extruder for the plastics processing, with an extruder barrel (8) essentially horizontally arranged and connected rigidly with a drive unit (10), whereby the drive unit (10) is connected rigidly with a base frame (9) , and whereby the base frame (9) is arranged movably on a foundation bearing (12), characterized in that at least one bearing support according to one of the preceding claims is provided on the extruder barrel (8)-

Documents:

1829-CHENP-2008 AMENDED CLAIMS 02-07-2012.pdf

1829-CHENP-2008 AMENDED PAGES OF SPECIFICATION 02-07-2012.pdf

1829-CHENP-2008 CORRESPONDENCE OTHERS 23-04-2012.pdf

1829-CHENP-2008 EXAMINATION REPORT REPLY RECEIVED 02-07-2012.pdf

1829-CHENP-2008 FORM-3 02-07-2012.pdf

1829-chenp-2008-abstract.pdf

1829-chenp-2008-claims.pdf

1829-chenp-2008-correspondnece-others.pdf

1829-chenp-2008-description(complete).pdf

1829-chenp-2008-drawings.pdf

1829-chenp-2008-form 1.pdf

1829-chenp-2008-form 18.pdf

1829-chenp-2008-form 26.pdf

1829-chenp-2008-form 3.pdf

1829-chenp-2008-form 5.pdf

1829-chenp-2008-pct.pdf