EP3529031A1

EP3529031A1 - Cylinder for a plastics-processing machine and method for operating an extruder

Info

Publication number: EP3529031A1
Application number: EP17768104.6A
Authority: EP
Inventors: Hans-Peter Schneider; Robert Breitenberger; Walter Breuning
Original assignee: KraussMaffei Technologies GmbH
Current assignee: KraussMaffei Technologies GmbH
Priority date: 2016-10-18
Filing date: 2017-09-14
Publication date: 2019-08-28
Also published as: WO2018072935A1; DE102016119858A1; US20210283816A1; CN109803806A

Abstract

The invention relates to a cylinder (30) for a plastics-processing machine (38), comprising at least two hollow-cylindrical bodies (10, 32). At least one portion of at least one hollow-cylindrical body (10) is provided with an inner coating (28), particularly a wear-protection layer (28), and can be attached to the other hollow-cylindrical body (32), the one hollow-cylindrical body (10) being attachable to the other hollow-cylindrical body (32) in a plurality of different positions. The invention further relates to a device (38) for processing a material and to a method for operating an extruder (38).

Description

CYLINDER FOR A PLASTIC PROCESSING MACHINE AND METHOD

TO OPERATE AN EXTRUDER

The invention relates to a cylinder, in particular a plasticizing, for a plastic processing machine. The invention further relates to an apparatus for processing a material, for example plastic, rubber or the like, with a multi-screw extruder, in particular a twin-screw extruder, wherein the extruder has at least two screws for processing the material, wherein the screws rotatably mounted in a cylinder and by means of at least one Drive are driven. In addition, the invention relates to a method for operating an extruder.

Devices for processing a material with an extruder have been known in practice for a long time. Such extruders are used for the processing of material, for example for the plasticization or melting of plastic or rubber, but also in the food industry. Two-screw or multi-screw extruders are particularly well suited for the melting or plasticization of material. The screws are the same or in opposite directions rotatably mounted in a housing with respect. Cylinder, wherein the screws are driven by a drive. The direction of rotation of the screws is predetermined by the course of the screw flights and the discharge direction of the material to be processed.

For certain applications, for example for the industrial production of semi-finished products, such as rigid PVC dryblend, etc., multi-shaft extruders such as twin-screw extruders are often used, since the requirements placed on the extruder here, are met by these machines particularly well. To emphasize is for example a good constant material intake, a careful material preparation and a high pressure build-up capacity. For such process tasks, counter-rotating, intermeshing (eg tightly combing) twin-screw extruders are often preferred in practice. Another advantage of the counter-rotating twin screw extruder is the self-cleaning, which is characterized by the Forced promotion results. Other devices such as co-rotating twin screw extruders, cascade extruders and planetary roller extruders or the like are also advantageous for similar or other processing tasks.

Due to the rotation of the screws and the filling of the cylinder and the processing of the material, forces which bring the screw into contact with the cylinder / housing usually occur during the operation of an extruder. In a counter-rotating, close-meshing twin-screw extruder, for example, resulting forces occur which press the screws in the region of an angle plane of about 45 ° to the axial plane of the twin screw against the cylinder inner wall. Due to the solid-solid contact of the outer circumference of the screw and the inner wall of the cylinder, apart from adhesive wear, abrasion also occurs through the processing of fillers (for example circles). Adhesive wear accounts for the majority of wear on the cylinder and worms in multi-screw extruders. With increasing mileage of the extruder, the wear on the inner cylinder wall increases due to the continuously acting forces (and the decreasing nitriding hardness of nitrided cylinders).

There are now various ways to minimize wear on the housing / cylinder and the screws. For example, DE 39 35 970 A1 discloses an extruder with an extrusion cylinder, which consists of a steel shell and in these cans made of hard metal or similar materials. If now adhesive wear occurs, then these cans are easily replaced.

Another possibility is described in EP 1 336 465 A1, in which the inner wall of the plasticizing cylinder is provided with a wear protection layer, wherein axially extending grooves are formed in the inner coating.

In high-performance extruders, the cylinders are exposed to high stresses, which despite wear-reducing measures, such as in the State of the art are described, resulting in a significant reduction in the service life of the cylinder and the device. Another disadvantage is that the extruder housing, if any, can only be provided with a specific wear protection layer. For different types of wear, however, different protective layers are required. Finally, damaged by wear housing usually have to be replaced with a new housing. When worn so always the entire component must be changed. This exchange is associated with high investment costs.

The present invention is therefore an object of the invention to provide a cylinder for a plastic processing machine and a device for processing a material of the type mentioned above and a method for operating an extruder, which allows the most cost-effective extension of the service life of the cylinder and thus the device becomes.

According to the invention the above object is achieved by a cylinder for a plastic processing machine having the features of claim 1. Accordingly, the cylinder has at least two hollow cylinder bodies, wherein at least one hollow cylinder body is provided at least in one section with an inner coating, in particular a wear protection layer, and can be attached to the other hollow cylinder body, wherein the one hollow cylinder body in several different positions on the other hollow cylinder body is attachable , The cylinder or extruder cylinder can thus be designed in several parts. The cylinder may have a plurality of cylinder segments in the form of hollow cylinder bodies. According to a preferred variant, the cylinder may be formed in two parts. The cylinder may therefore comprise a first hollow cylinder body and a second hollow cylinder body. The first hollow cylinder body may be separated from the hollow cylinder body. The cylinder may alternatively have more than two, for example, three, four, five or six hollow cylinder body. In accordance with the invention it has been recognized, therefore, that in contrast to the previous practice, not only measures of wear protection on the screws or the housing can increase the service life of the housing, but that an increase in service life can be achieved in that the cylinder at different Worn areas. This is technically achieved in a particularly simple and sophisticated manner in that the cylinder is designed in several parts, preferably in two parts, and at least one of the resulting hollow cylinder body is provided at least in one section with a wear protection layer.

In the case of wear of a hollow cylinder body can be easily disassembled and mounted in a different position, such that a wear of not or hardly affected point of the inner wall of the hollow cylinder body moves to the position of a strong closing point. Kinematically, the wear is usually always caused in the upper part of the cylinder segment. By placing the hollow cylinder body in varying different positions, a higher, e.g. double, wear volume and thus a longer service life. Thus, although wear occurs, but this occurring in other areas of the cylinder body wear makes it possible to increase the life of the cylinder significantly, sometimes more than doubling. Furthermore, an individual adaptation of the selected wear protection layer to the respective requirement of the cylinder zone is made possible. The cylinder can thus be used again with his / her hardly or hardly occlusive location (s). This extends the service life and the service life of the machine is significantly increased. Likewise, no further investment costs, e.g. for a new cylinder or housing.

The hollow cylinder body of the cylinder provided with the inner coating may be fastened or mounted in a plurality of positions, for example two, on the other hollow cylindrical body of the cylinder. The one hollow cylinder body can be attached to the other hollow cylinder body relative to an original position in a rotated by 180 °, 120 °, 90 ° or 45 ° position. The Originating position is the position of the hollow cylinder body in which it has been attached to the other hollow cylinder body for the first or previous time.

Alternatively or additionally, the hollow cylinder body may be configured to be rotatable / rotatable about an angle defined by the cylinder and / or an extruder, depending on the configuration of the cylinder and / or an extruder, about an axis (for example the longitudinal axis) of the cylinder.

The one hollow cylinder body can be detachably attached to the other hollow cylinder body. For example, the hollow cylinder body can be screwed together.

The hollow cylinder body may each have at least two mutually parallel longitudinal bores, which overlap to form a spectacle bore. Alternatively or additionally, hollow cylinder body may have three, four, five or more parallel longitudinal bores. The hollow cylinder body may be attached to each other so that the longitudinal axes of their holes are congruent to each other. The cylinder can thus have two or more mutually parallel longitudinal bores.

The inner coating may be formed substantially in the gusset region of the eyeglass bore. Alternatively or additionally, the inner coating may be formed in a region of an angle plane of approximately 45 ° to an axial plane of the hollow cylinder body or cylinder. Alternatively, the inner coating may extend over the entire inner surface of the hollow cylinder body. The hollow cylinder body may have one or more inner coatings. The inner coatings can be arranged in sections on the hollow cylinder body.

According to a variant, the other hollow cylinder body may be provided at least in one section with an inner coating, in particular a wear protection layer. It is also possible for all hollow cylinder bodies of the cylinder to be provided with an inner coating at least in one section be. Preferably, however, only the hollow cylinder body of the cylinder are provided with an inner coating, which are arranged in zones of greatest wear.

The inner coating of the one hollow cylinder body may be different from the inner coating of the other hollow cylinder body or the other hollow cylinder body. It is also conceivable that selected hollow cylinder body have mutually different wear protection layers. Due to the separable design of the cylinder different wear protection layers can be realized in the respective zones of the hollow cylinder body. In a variant, the inner wall of a hollow cylindrical body may have different inner coatings. This has the advantage that the wear protection layers can be adapted to the respective requirements and different wear conditions.

The inner coating or wear protection layer may comprise an alloy, preferably metal alloy, ceramic and / or bimetal, preferably tungsten carbide, or any combination thereof. Additionally or alternatively, the inner coating may be made by curing, for example, inductive hardening.

According to a further aspect, an apparatus for processing a material, for example plastic, rubber or the like, with a multi-screw extruder, in particular a twin-screw extruder is specified, wherein the extruder has at least two screws for processing the material, wherein the screws rotatable in a as above and / or cylinders described below are stored and driven by at least one drive.

The worm (s) can have an outer coating, in particular a wear-resistant coating, at least in one section. The outer coating on the worm (s) may be in the range of Be provided inside coating of the cylinder or the hollow cylinder body. That is, the outer coating may be provided on the worm (s) in the region where, opposite to the worm, the inner coating portion of the cylinder or hollow cylindrical body is provided. The screw (s) may also have an outer coating which extends over the part of the screw which is located inside the hollow cylinder body, in particular the hollow cylinder body with an inner coating. Alternatively, the outer coating may extend over the entire screw length. The screw (s) may have one or more external coatings. In one variant, the outer coating can be designed as a wear protection layer which is adequate or corresponding to the inner coating of the cylinder. The outer coating of the screw (s) may comprise an alloy, preferably metal alloy, ceramic, molybdenum and / or bimetal, preferably tungsten carbide, or any combination thereof. In one variant, the screw (s) may have one or more external coatings. For example, the screw (s) may have two outer coatings. These two outer coatings may be, for example, molybdenum and tungsten carbide.

The multi-screw extruder can be designed as an opposite or in the same direction rotating extruder. The drive may comprise an operable in two directions of rotation motor.

When operating the multi-screw extruder resulting due to the rotation of the screw and the material filling of the extruder forces cause wear on the cylinder inner wall. If the position of at least one hollow cylinder body of the cylinder is exchanged, that is to say it is again attached to the other hollow cylinder body of the cylinder at another position, the wear occurs at other areas of the hollow cylinder body. In these areas, the maximum or at least predominantly wear protection layer is present after previous operation, so that the cylinder can be used for a significantly increased service life. In addition, the changed forces possibly lead to a modified wear on the screws, so that the duration of the screws may be extended in some circumstances.

In a particularly preferred embodiment for processing special materials, the extruder could be designed as a counter-rotating or counter-rotating twin-screw extruder with a meshing, preferably tightly intermeshing, screw profile. However, any other type of extruder, for example single-screw extruder, cascade or planetary roller extruder or the like could be conceivable. The choice of the right extruder depends on the process task. The screws could, for example, be designed as parallel screws or as conical screws.

In another aspect, a method of operating an extruder having at least two screws is provided. The method according to the invention could be used, in particular, for operating a device according to the above and / or below embodiments, wherein a hollow cylinder body of the cylinder is mounted in a different position relative to its original position. In the method is advantageous that the service life of the cylinder can be significantly increased by the possibility of the subsequent different attachment of the hollow cylinder body of the cylinder to the other hollow cylinder body of the cylinder.

Depending on the type of extruder and / or material being processed, processing of the material will be stopped. This operating point can be chosen differently depending on the process task. For example, the operating point could be selected such that the wear occurring is still so slight that it does not lead to any significant damage to the cylinder, the screws and / or the product in the wear area. Advantageously, however, the operating point could also be chosen so that the wear and the resulting damage to a usability of the product. The operating time could thus be determined by the type of housing and / or the judge the processed material. The operating time could be selected depending on the wear of the cylinder inner wall and / or the screws and / or the sensitivity of the material and / or product. The operating point at which production is stopped could therefore be calculated partly for materials to be processed or determined from empirical values. However, the operating point could be determined at least from the quality of the extruded product.

There are various possibilities for embodying and developing the teaching of the present invention in an advantageous manner. For this purpose, on the one hand to the claims and on the other hand to the following explanation of a preferred embodiment of the cylinder according to the invention for a plastic processing machine and the apparatus for processing a material with reference to the drawings. In conjunction with the explanation of the preferred embodiment of the cylinder according to the invention, the apparatus and the method according to the invention for operating an extruder with reference to the drawings, generally preferred embodiments and developments of the teaching are also explained. Further aspects, features and advantages of the cylinder and device disclosed here also result from the exemplary embodiments explained below as well as from the figures. Show it:

Fig. 1 in a partially sectioned side view of an embodiment of a

Hollow cylinder body with an inner coating;

2 shows a partially sectioned side view of an exemplary embodiment of a two-part cylinder with the hollow cylinder body according to FIG. 1 and a further hollow cylinder body;

Fig. 3a in a sectioned, schematic representation

Embodiment of an apparatus for processing a material with the cylinder of FIG. 2; and Fig. 3b in a sectional, schematic representation of the apparatus for processing a material according to Fig. 3a, wherein the hollow cylinder body has been attached as shown in FIG. 1 at a different position.

The exemplary embodiments are explained below by way of example. Matching or comparable elements are given the same reference numerals.

In Fig. 1, an embodiment of a hollow cylinder body 10 is shown in a partially sectioned side view. The longitudinal axis 12 is an axis of rotation of the hollow cylinder body 10. The longitudinal axis 12 extends in the process direction of the hollow cylinder body 19. Along its longitudinal axis, the hollow cylinder body 10 has two ends 14. The ends 14 of the hollow cylinder body 10 thus form opposite side surfaces.

At each end 14, the hollow cylinder body 12 has a substantially in the vertical direction to the longitudinal axis 12 of the hollow cylinder body 10 extending projection 1 6. The projection 1 6 is formed in the present embodiment as a flange 16. The flange 1 6 is integrally formed with the hollow cylinder body 10 and therefore forms a flange portion 1 6 of the hollow cylindrical body 10. The flange portion 16 may have a round, but preferably, as in the present embodiment, also a rectangular cross-section. The cross section of the flange 16 extends in a plane which is substantially perpendicular or transverse to the longitudinal axis 12 of the hollow cylinder body 10. The cross sections of the two flange sections may have the same or, as in the present exemplary embodiment, a different size cross-sectional area. The flange portion or flange 1 6 has one or more holes 18. The holes 18 may be designed as through holes or blind holes. The

Holes 18 of the flange 1 6, as in the present embodiment, have an internal thread. The holes 18 may thus be formed as threaded holes 18. By means of these threaded bores 18, the hollow cylinder body 10 can be attached to another hollow cylinder body and preferably screwed thereto by means of screws or pins (shown in Fig. 2). Furthermore, the flange portion 1 6 recesses 20, for example in the form of a hexagon, have. Other forms, such as triangle, square and round are also conceivable. The recesses 20 may also be configured as a bore. The recesses 20 may be attached only to one of the two flange portions 16 (in Fig. 1 at the right flange portion) or at both flange portions 16 (not shown in Fig. 1). The flange sections 1 6 can additionally or alternatively have bores 22, preferably blind bores 22. These blind bores 22 can also be attached to only one of the two flange sections 16 (in FIG. 1 on the left flange section) or on both flange sections 16 (not shown in FIG. 1). The two flange portions 1 6 can thus be configured similar or equal. The holes 18, recesses 20 and / or the blind bores 22 extend substantially in a direction parallel to the longitudinal axis 12 of the hollow cylinder body 10th

The hollow cylinder body 10 has two parallel longitudinal bores 24, which extend substantially in the direction of the longitudinal axis 12 of the hollow cylinder body 10. In the present exemplary embodiment, the longitudinal bores 24 and the formation of a spectacle bore 24 (shown schematically in FIGS. 3a and 3b) are superimposed. The eyeglass bore 24 defines an inner surface 26 of the hollow cylinder body 10. Alternatively, the hollow cylinder body 10 depending on the application only a longitudinal bore 24 or more, for example, three, four or five longitudinal holes 24 have, in the latter case, the longitudinal holes 24 can pass at least in pairs.

As shown in FIG. 1, the hollow cylinder body 10 has an inner coating 28 at least in one section. In the present embodiment, the

Inner coating 28 over the entire inner surface 26 of the hollow cylinder body 10th educated. Alternatively, the inner coating 28 may be formed only in sections on the inner surface 26 of the hollow cylinder body 10. For example, the inner coating 28 is formed substantially in the gusset region of the eyeglass bore 24 of the hollow cylinder body 10. The inner coating 28 is in particular a wear protection layer 28. The wear protection layer 28 is preferably made of a wear-resistant material. The wear protection layer 28 may comprise, for example, an alloy, preferably metal alloy, ceramic, and / or bimetal, preferably tungsten carbide, or a combination thereof. Alternatively or additionally, the wear protection layer 28 may be made by curing, for example, inductive hardening. In the present embodiment, the wear protection layer 28 is formed of tungsten carbide.

Fig. 2 shows a partially sectioned side view of an embodiment of a two-part cylinder 30 with the hollow cylinder body 10 of FIG. 1 and another hollow cylinder body 32. However, it can also several, e.g. three, four, five, etc. hollow cylinder body 10 and / or hollow cylinder body 32 form a cylinder 20.

The hollow cylinder body 32 essentially corresponds to the hollow cylinder body 10. The hollow cylinder body 32 thus essentially has the features described with reference to the hollow cylinder body 10 and shown in FIG. However, a difference between the hollow cylinder body 32 and the hollow cylinder body 10 is that in the present embodiment, the hollow cylinder body 32 has no inner coating 28. Alternatively, the hollow cylinder body 32 may have an inner coating 28 at least in one section, preferably on the inner surface 26 of its longitudinal bore (s) 24. In one variant, the hollow cylinder body 32 may have an inner coating in the form of a wear protection layer 28 on its entire inner surface 26. The inner coating 28 of the hollow cylinder body 10 may be different from the inner coating 28 of the hollow cylinder body 32. The inner coating 28 may thus be adapted to the respective process zone of the cylinder 30. The However, inner coating 28 may alternatively be formed the same at the hollow cylinder body 10, 32.

The hollow cylinder body 10 is attached to the other hollow cylinder body 32, wherein the hollow cylinder body 10 is attachable to the other hollow cylinder body 32 in a plurality of different positions. For this purpose, the hollow cylinder body 10 is detachably attached to the other hollow cylinder body 32 in the present embodiment. As shown in Fig. 2, the two hollow cylindrical body 10 and 32 are screwed together by means of screws 34. Alternatively or additionally, the hollow cylinder body 10, 32 by means of pins, threaded rods, lock screws, etc. are interconnected. In Fig. 2 this is exemplified with grub screws 36. The hollow cylinder body 10, 32 are attached by means of their flange portions 1 6 together. They are so interconnected that the eyeglass bore 24 of the hollow cylinder body 10 are aligned with the eyeglass bore 24 of the hollow cylinder body 32 in the longitudinal direction along the longitudinal axis 12 congruent. The longitudinal axes of the eyeglass holes 24 are thus formed congruent to each other.

As shown in FIG. 2, due to the split configuration of the cylinder 30, the hollow cylinder body 10 can be disassembled again. In particular, in the case of wear, the hollow cylinder body 10 by means of screws 34 and pins 36 are released from the hollow cylinder body 32 again. The hollow cylinder body 10 is thus relative to its original position (ie, to its originally mounted position) in an example 180 °, 120 °, 90 ° or 45 ° twisted position on the other hollow cylinder body 32 attachable. The hollow cylinder body 10 can be rotated about its longitudinal axis 12 and then be attached to the other hollow cylinder body 32 again. Alternatively or additionally, the hollow cylinder body 10 can also be rotated about an axis perpendicular to the longitudinal axis 1 2 axis. This vertical axis is preferably in the horizontal plane of the hollow cylinder body 10. Favor is a rotation of the hollow cylinder body 10 by 180 ° about the longitudinal axis 12 and / or about the longitudinal axis 12 vertical axis of the hollow cylinder body 10. Alternatively or additionally, the hollow cylinder body 10 may be configured to be rotatable / rotatable around an axis of the cylinder 30 for any desired and / or depending on the configuration of the cylinder 30 and / or an extruder angle. The hollow cylinder body 10 can thus be mounted in two or more positions on another hollow cylinder body.

In the Fign. 3a and 3b is a sectional, schematic view of an embodiment of a device 38 for processing a material, in this case plastic, with the cylinder 30 shown in FIG. 2. The device comprises an extruder, wherein the extruder is designed as a multi-screw extruder. In the present embodiment, the extruder is a twin-screw extruder. The extruder has two screws 40 for plasticizing plastic. The screws are rotatably mounted in the cylinder 30. As shown in Figs. 3a and 3b, the screws are stored in the eyeglass bore 24 of the cylinder 30.

The screws 40 may have an outer coating, in particular a wear protection layer, at least in one section. The outer coating on the screws 40 may be provided in the region of the inner coating 28 of the cylinder 30 or the hollow cylinder body 10. That is, the outer coating may be provided on the screws 40 in the region where, opposite to the screw 40, the region of the inner coating 28 of the cylinder 30 or hollow cylinder body 10 is provided. In one variant, the outer coating can be designed as a wear protection layer that is adequate or corresponding to the inner coating 28 of the cylinder 30. The outer coating of the screws 40 may comprise an alloy, preferably metal alloy, ceramic, molybdenum and / or bimetal, preferably tungsten carbide, or any combination thereof. In one variant, the screws 40 may have one or more external coatings. For example, the screws may have two outer coatings. These two outer coatings may be, for example, molybdenum and tungsten carbide. In the present embodiment, the screws 40 have an outer coating which extends over the part of the screw, the is within the hollow cylinder body 10, wherein the outer coating is formed as the inner coating 28 of the hollow cylinder body 10 adequate wear protection layer and tungsten carbide.

The screws 40 are driven by means of a drive, not shown. The drive comprises an operable in two directions of rotation motor. In addition, the drive may comprise a transmission and / or transmission elements in the form of coupling elements. The extruder can be configured as an opposing or co-rotating extruder. In the present embodiment, the extruder is designed as a meshing (here sealingly combing) counter-rotating (indicated by the arrows in Figures 3a and 3b) twin-screw extruder. The drive drives the first worm 40 (in Figs. 3a and 3b the left worm) counterclockwise and the second worm 40 (in Figs. 3a and 3b the right worm) in a clockwise direction. It is also conceivable, however, a reverse sense of rotation of the screws.

In Fig. 3a, the direction of rotation of the individual screws 40 and the acting pressing forces F are shown. In operation, the screws 40 act on the cylinder 30 and thus on the hollow cylinder body 10. Wear occurs in particular on the hollow cylinder body 10 in the range from about 9:00 to 11:00 and 13:00 to 15:00; schematically represented by the thickened circular arcs 42. The cylinder wear occurs as shown in Fig. 3a on the wear protection layer 28 on. Thus, the hollow cylinder body 10 is not directly damaged. Depending on the processed plastic material processing is stopped after a certain period of operation, in which the occurring cylinder wear 42 is still so low that it still leads to no significant damage to the product, the cylinder 30 and / or the screws 40. This is usually the case if only the wear protection layer 28 of the hollow cylinder body 10 is affected by wear. When this operating point is reached, the hollow cylinder body 10 of the extruder cylinder 30 is mounted in a different position relative to its original position. In the present embodiment, the hollow cylinder body 10 is first released by means of the screws 34 of the hollow cylinder body 32. thereupon the Hohizylinderkorper 10 is rotated by 180 ° about its longitudinal axis 12. The Hohizylinderkorper 10 is in this position again attached to the Hohizylinderkorper 32 or screwed. The Hohizylinderkorper 10 was thus from its original position (as shown in Fig. 3a) in a different position (here rotated by 180 °) attached to the other Hohizylinderkorper 32 (as shown in Fig. 3b.).

3b now shows the Hohizylinderkorper 10 in a 180 ° rotated about the longitudinal axis 12 and screwed back to the other Hohizylinderkorper 32 position. The existing cylinder wear 42 is therefore now in the range about 7:00 to 9:00 and 15:00 to 17:00 clock. If the processing of plastic material is now resumed, the cylinder wear now takes place on the not yet occlusive or hardly affected wear protection layer 28 in the upper part of the Hohizylinderkorper 10 or again at around 9:00 to 11:00 and 13:00 to 15:00 clock area.

For further details reference is made to avoid repetition to the general description.

Finally, it should be expressly understood that the embodiment described above or embodiments only serves to discuss the claimed teaching, but does not limit this to the embodiment.

Reference numeral list Hollow cylinder body with coating

longitudinal axis

The End

flange

threaded holes

recesses

Blind holes

Longitudinal drilling / eyeglass drilling

palm

Inner coating / wear protection layer cylinder

Hollow cylinder body without coating screws

screws

Device / extruder

Screw (s)

Cylinder wear

contact forces

Claims

claims

1 . Cylinder (30) for a plastic processing machine (38) with at least two hollow cylindrical bodies (10, 32), wherein at least one hollow cylinder body (10) is provided at least in one section with an inner coating (28), in particular a wear protection layer (28), and at the other

Hollow cylinder body (32) is attachable, wherein the one hollow cylinder body (10) in a plurality of different position on the other hollow cylinder body (32) is attachable.

2. Cylinder (30) according to claim 1,

characterized in that the one hollow cylinder body (10) relative to an original position in a rotated by 180 °, 120 °, 90 ° or 45 ° position on the other hollow cylinder body (32) is attachable.

3. cylinder (10) according to claim 1 or 2,

characterized in that one hollow cylinder body (10) is releasably attached to the other hollow cylinder body (32).

4. Cylinder (10) according to one of the preceding claims,

characterized in that the hollow cylinder body (10, 32) are screwed together.

5. cylinder (10) according to any one of the preceding claims,

characterized countersigns that the hollow cylinder body (10, 32) each have at least two mutually parallel longitudinal bores (24) which intersect to form a spectacle bore (24).

6. cylinder (10) according to claim 5,

characterized countersigns that the inner coating (28) is formed substantially in the gusset region of the eyeglass bore (24).

7. Cylinder (10) according to one of the preceding claims,

characterized in that the inner coating (28) over the entire inner surface (26) of the hollow cylindrical body (10) or in an area of an angle plane of about 45 ° to an axial plane of the cylinder (10) is formed.

8. Cylinder (10) according to one of the preceding claims,

characterized countersigns that the other hollow cylinder body (32) at least in a section with an inner coating (28), in particular a

Wear protection layer (28) is provided.

9. cylinder (10) according to claim 6,

characterized in that the inner coating (28) of the one

Hollow cylinder body (10) of the inner coatings (28) of the other

Hollow cylinder body (32) is different.

10. Cylinder (10) according to one of the preceding claims,

characterized in that the inner coating (28) is an alloy, preferably metal alloy, ceramic and / or bimetal, preferably

Tungsten carbide, or a combination thereof.

1 1. Cylinder (10) according to one of the preceding claims,

characterized in that the inner coating (28) by hardening, for example, inductive hardening, is made.

12. Device (38) for processing a material, for example plastic, rubber or the like, with a multi-screw extruder (38),

in particular a twin-screw extruder (38), wherein the extruder (38) has at least two screws (40) for processing the material, wherein the screws (40) are rotatable in a cylinder (30) according to one of

stored above claims and are driven by at least one drive.

13. Device (38) according to claim 12,

characterized in that the screws (40) have an outer coating, in particular a wear protection layer, at least in one section.

14. Device (38) according to claim 13,

characterized in that the outer coating on the screws (40) in the region of the inner coating of the cylinder (30) and the hollow cylindrical body (10) is provided, wherein the outer coating is formed as an internal coating for adequate wear protection layer.

15. Device (38) according to claim 13 or 14,

characterized in that the outer coating of the screws (40) comprises an alloy, preferably metal alloy, ceramic, molybdenum and / or bimetal, preferably tungsten carbide, or a combination thereof.

16. Device (38) according to one of claims 12 to 15,

characterized in that the multi-screw extruder (38) is designed as a counter-rotating or co-rotating extruder (38).

17. Device (38) according to any one of claims 12 to 1 6,

characterized countersigns that the drive one in two directions

operable engine includes.

18. A method for operating an extruder (38), comprising at least two screws (40), in particular a device (38) according to one of claims 12 to 17, wherein the processing of the material is stopped and a hollow cylinder body (10) of the extruder cylinder (30 ) is mounted in a different position relative to its original position.