Internal mixer for rubber processing and method for replacing components of an internal mixer in case of wear

Abstract

An internal mixer (1) for rubber processing has a mixing chamber (2) and a rotor (4) for mixing a mixture in the mixing chamber (2), wherein the rotor (4) has a rotor shaft (5) which is guided through a wall (3) of the mixing chamber (2), a first and a second sealing component (6, 7) which are arranged in the region of the wall (3) around the rotor shaft (5) and are designed to seal the mixing chamber (2) to the outside, wherein the first sealing component (6) rotates when the rotor shaft rotates and the second sealing component (7) does not rotate when the rotor shaft (5) rotates, wherein the first and / or second sealing component (6, 7) has a carrier part (11, 12) and a wearing part (9, 10), wherein the wearing part (9, 10) is designed to be replaced when worn, without a complete replacement of the sealing component (6, 7) being necessary.

Description

The present invention relates to an internal mixer which can be used, for example, for rubber processing. The internal mixer has, for example, a feed shaft through which the mixture constituents are introduced. In a mixing chamber, the homogenization of the mixed material takes place by counter-rotating rotors.In the patent specification EP 3 746 278 B1, such an internal mixer is disclosed.Since the bearing and the drive of the rotors are located outside the mixing chamber, the rotor shafts are led out of the mixing chamber through a wall of the mixing chamber. In order to prevent liquid and solid mixture constituents from leaving the mixing chamber through the rotor shaft passage, the mixers have seals, in particular a so-called dust seal system.The dust sealing system usually comprises two components which are pressed together during the mixing process. One of the components is fixedly connected to the rotor and rotates therewith, while the other component is fixedly connected to the mixer housing and does not rotate. For example, the components are each designed in the form of rings or sleeves which are arranged around the rotor shaft. In the event of wear at the boundary surfaces of one or both components, the respective component is usually exchanged. However, replacement of the entire component is not permanent.In order to prevent premature wear of the components due to abrasion and high temperatures, lubricating oil can be injected into the sealing gap. However, the injected oil may easily flow out of the seal gap. In order to ensure that the entire contact surface of the components is sufficiently wetted with oil and thus avoid overheating of the system due to frictional heat, it is necessary to introduce a considerable amount of lubricating oil into the sealing system. In order that even more remote areas are reliably supplied with lubricating oil, individual lubricating points are overproved with oil. The oil which after a while is contaminated with, for example, mixture constituents, can leave the mixer through laterally mounted gutters and requires environmentally friendly disposal. The high consumption of oil as a result of the oversupply is moreover not lasting.The object of the present invention is to provide an internal mixer with improved properties.According to a first aspect, an internal mixer for rubber treatment has a mixing chamber and a rotor for mixing a mixed material in the mixing chamber. The rotor has a rotor shaft which is guided through a wall of the mixing chamber. The mixing chamber has a first and second sealing component which are arranged in the region of the wall around the rotor shaft and are designed to seal the mixing chamber outwards, wherein the first sealing component rotates together with a rotation of the rotor shaft and the second sealing component does not rotate with a rotation of the rotor shaft, wherein the first and / or second sealing component has a carrier part and a wear part, wherein the wear part is designed to be replaced in the event of wear without a complete replacement of the sealing component being required.In this way, replacement can be carried out at low cost during wear. In addition, the wear parts can be easier to handle than the entire sealing component, so that the replacement can be carried out more quickly and production losses can be minimized.The wear part and the associated support part can be formed circumferentially around the rotor shaft. The wear part can be formed annularly, for example. The carrier part can be formed, for example, in an annular or sleeve-shaped manner. The wear part is arranged, for example, on an end face of the carrier part.Both sealing components can each have a wear part and a support part. It is also possible that only one sealing component has a wear part. In this case, the other sealing component can only be completely replaced.The wear part can be composed of a plurality of individual parts. The wear part can be separated into the individual parts for replacement, so that it is not necessary to remove further components, such as the rotor, for example.For example, the individual parts are each configured only partially circumferentially around the rotor shaft, while the complete wear part rotates completely around the rotor shaft.The wear part may be configured to allow oil flow through the wear part. For example, the wear part permits an oil flow at a plurality of points, while an oil flow is permitted only at fewer points through the associated carrier part. For example, the carrier part has one or a few supply channels for supplying oil for lubricating a sealing gap between the sealing components. It is also possible to form the supply channel as a separate element from the rest of the carrier. For example, the supply channel can be produced in the form of a three-dimensional component by means of metal / plastic printing methods. The wear part has, for example, more through-channels, so that a uniform distribution in the sealing gap is ensured.For example, the through-channels are introduced, in particular drilled, into the wearing part. A plurality of such channels can be more easily introduced into the wearing part than into the entire sealing component.It is also possible that the wear part is formed from a porous material, so that an oil flow through the wear part is made possible due to the porosity. For example, the wear part comprises a sintered metal as material.For the uniform distribution of the oil from the carrier part to the wear part, the sealing component can have a distributor channel. The distributor channel is located, for example, in the region of an interface between the carrier part and the wear part and is formed, for example, in a circumferential manner. Thus, the oil from one or more supply channels can be distributed uniformly over the surface of the wear part. Via the wearing part, a uniform distribution to the sealing gap can then take place. The distributor channel can be formed as a separate element from the remaining carrier part.The wear part may comprise a different material than the support part. For example, the material of the carrier part is designed for mechanical load capacity, while the material of the wear part is designed for the sealing function and wear protection. For example, the support part comprises a metal and the wear part comprises a plastic. Other material combinations are also possible. It is also possible for the carrier part and the wear part to be formed from the same material.The wear part is arranged, for example, in a groove of the carrier part. The wear part can be fastened to the carrier part, for example, by means of a fastening means such as a bayonet lock. The wear part can alternatively or additionally be fastened to the carrier part by a fastening element. For example, the wear part is fastened to the carrier part by a pin or a screw.According to a further aspect, in a method for exchanging components of an internal mixer during wear, the internal mixer as described above is provided. When the sealing component wears, only the wearing part, but not the supporting part, is exchanged. A multi-part wear part can be disassembled into its individual parts during replacement.Components can thus be exchanged in a simple, cost-effective and lasting manner. In addition, the production loss can be minimized.The present invention encompasses several aspects, in particular apparatuses and methods. The features, properties and embodiments described for one of the aspects are also intended to apply accordingly to the other aspect.In addition, the description of the subject matter provided herein is not limited to the specific embodiments. Rather, the features of the individual embodiments can be combined with one another-insofar as technically expedient.The subject matters described here are explained in more detail below with reference to schematic exemplary embodiments.The following are shown: FIG. 1 shows a detail of an embodiment of an internal mixer in sectional view, FIG. 2 shows a detail from FIG. 1, FIG. 3 shows a first embodiment of a wear part in plan view, FIG. 4 shows a further embodiment of a wear part in plan view, FIG. 5 shows a further embodiment of a wear part in plan view, FIG. 6 shows a further embodiment of a wear part in plan view, FIG. 7 shows an embodiment of a sealing component in sectional view, FIG. 8 shows an embodiment of an internal mixer in sectional view.Preferably, like reference numerals refer to functionally or structurally corresponding parts of the various embodiments in the following figures.FIG. 8 shows an embodiment of an internal mixer 1 for mixing a mixed material, in particular a rubber mixture. The internal mixer 1 has a mixing chamber 2 which is surrounded by a wall 3. The mixing chamber 2 is filled with raw material for the mixed material through a feed shaft. The raw material is pressed into the mixing chamber 2 by a punch. Rotors 4 are arranged in the mixing chamber 2, each of which has a rotor shaft 5 which is guided through the wall 3. The rotors 4 have rotor vanes within the mixing chamber 2. In particular, the rotor vanes of the rotors 4 can be configured to be tangential or intermeshing. The internal mixer 1 is designed in particular for discontinuous mixing operation. The ready-mixed mixed material can be ejected from the mixing chamber 2 by a discharge flap.FIG. 1 shows a detail of an internal mixer 1, in particular of the internal mixer 1 from FIG. 8, in a representation rotated by 90° about a vertical axis.To prevent or reduce the emergence of dust from the mixing chamber 2 through a gap between wall 3 and rotor shaft 5, the internal mixer 1 has, for each rotor 4, a first sealing component 6 and a second sealing component 7, which press one on the other during the mixing process. The first sealing component 6 is firmly connected to the rotor shaft 5 so that it rotates with the rotor shaft 5 during the mixing process. In particular 1, the first sealing component 6 is sleeve-shaped and is plugged onto the rotor shaft 5.The second sealing component 7 does not rotate during the mixing process and is fastened, for example, to the wall 3 or another housing part. The second sealing component 7 is also sleeve-shaped, for example, and is arranged spaced apart around the rotor shaft 5. The second sealing component 7 may partially surround the first sealing component 6.Abrasive wear occurs due to the relative movement of the sealing components 6, 7. Even by lubricating a sealing gap 8, i.e. an intermediate space between the sealing components 6, 7, the wear cannot be prevented completely. In order to avoid an expensive and expensive complete replacement of the sealing components 6, 7, the sealing components 6, 7 have wear parts 9, 10 which can be replaced separately.FIG. 2 shows an enlarged detail from FIG. 1.The wear parts 9, 10 are of annular design. The wear parts 9, 10 form the boundary surfaces of the sealing components 6, 7, so that the wear parts 9, 10 are pressed against one another. In particular, the end faces of the wearing parts 9, 10 face each other and are spaced apart from each other only by the sealing gap 8. The first wear part 9 is arranged in the region of the flange of the first sealing component 6 and fastened there. The second wear part 10 is arranged on the end face of the second sealing component 7 and fastened there.Thus, the sealing components 6, 7 each have a carrier part 11, 12 to which a wear part 9, 10 is fastened. The support parts 11, 12 are of annular or sleeve-shaped design. The sealing components 6, 7 are thus each embodied in two parts. The support parts 11, 12 take over the mechanical load, while the sealing function and the wear protection are ensured by the wear parts 9, 10. The replacement of only the wearing parts 9, 10 is more cost-effective than the replacement of the entire sealing components 6, 7.For supplying the friction surfaces with lubricating oil, the second sealing component 7 has a supply channel 13 which is drilled through the second carrier part 12. A plurality of supply channels 13 can also be provided. The supply passage 13 is connected to an oil supply. Due to the complicated bore, only one or a few supply channels 13 are introduced. For more uniform distribution of the oil in the sealing gap 8 and for reducing the oil requirement in the sealing system, the wearing part 10 is designed in such a way that an oil flow 15 through the second wearing part 10 is made possible at many locations (see detailed description in the subsequent figures).In addition, the second sealing component 7 has a distributor channel 14 which is of annular design and distributes the oil to the end face of the second wear part 10 facing the carrier part 12. Thus, the through-channels 16 and thus the sealing gap 8 are supplied with oil uniformly. The distributor channel 14 is milled into the second carrier part 12, for example.FIG. 3 shows a second wear part 10 in a plan view of an end face. This is in particular the second wear part 10 from FIG. 2, and it can also be the first wear part 9. Both wear parts 9, 10 can also be designed to be largely identical, wherein the first wear part 9 has, for example, no through-channels 16.The second wear part 10 has a plurality of through-channels 16. The through-channels 16 are distributed uniformly over all angular positions of the second wear part 10. The plurality of through-channels 16 allow the lubricating oil to be distributed uniformly in the sealing gap 8. When combined with a circumferential distributor channel 14, the lubricating oil reaches all the through-channels 16, which through-channels 16 are introduced, for example, as a bore into the second wear part 10.By distributing the oil more evenly, oversupply can be reduced and oil consumption can be reduced. The more uniform lubrication allows the service life of the sealing components 6, 7 to be extended.The two-part construction of the respective sealing components 6, 7 enables new material combinations. The support part 11, 12 only needs to take over the mechanical load here, while the wear part 9, 10 ensures the sealing function and the wear protection. Suitable materials for the wear parts 9, 10 are, for example, plastics, organic materials, ceramic semi-metallic materials (composite materials), fully metallic materials and carbon fiber.It is also possible to use porous materials which, because of their porosity present, allow the oil to pass through without the need for holes.In Fig. 4 there is shown a first wear member 9 formed of a porous material. For example, it is a sintered metal. The porous structure of the material stores the lubricant, minimizes the lateral leakage of oil, and thus can reduce the overall consumption.This can also be a second wear part 10. It is also possible to produce both wear parts 9, 10 from a porous material. In addition, the wear parts 9, 10 can each also be manufactured both from a porous material and also have through-channels 16.In particular, a combination of a first wear part 9 made of a porous material according to FIG. 4 and a second wear part 10 with drilled through-channels 16 according to FIG. 3 is possible, as is also shown in FIGS. 1 and 2.FIGS. 5 and 6 show further embodiments for first and second wear parts 9, 10. In contrast to the wear parts 9, 10 from FIGS. 3 and 4, the wear parts 9, 10 are not formed in one piece, but in multiple pieces.In particular, the wear parts 9, 10 are each composed of three individual parts 19, 20, 21. More or fewer individual parts 19, 20, 21 are also possible. For replacement, the wearing parts 9, 10 can be separated into the three individual parts 19, 20, 21, so that assembly and disassembly are facilitated. Thus, maintenance is simplified and the running cost can be reduced. A further advantage of the multi-part embodiment is that the wear parts 9, 10 require less storage space and the shipping of the divided wear parts 9, 10 is easier.Each of the individual parts 19, 20, 21 can be detachably fastened, for example, separately to the second carrier part 12.FIG. 7 shows an embodiment of a second sealing component 7 comprising a second carrier part 12 and a second wear part 10.The second wear part 10 can be inserted positively into the second carrier part 12. For example, the carrier part 12 has, in the region of its end face, a circumferential groove 17, into which the wear part 10 is inserted. In particular, the wear part 10 can have a reduced diameter in this region.The wear part 10 can additionally be fixed to the carrier part 12 by a fastening means, in particular a releasable fastening means. For example, a fixing can take place via one or more pins 18. For example, in a multi-part embodiment, each individual part 19, 20, 21 is fixed by at least one pin 18. Alternatively, fixing by screws is also possible, for example. It is also possible to fasten the carrier part 12 and the wear part to a component of the internal mixer 1 with the same screw.Reference numerals denote reference numerals1 Internal mixer 2 Mixing chamber 3 Wall 4 Rotor 5 Rotor shaft 6 First sealing component 7 Second sealing component 8 Sealing gap 9 First wear part 10 Second wear part 11 First carrier part 12 Second carrier part 13 Supply channel 14 Distributor channel 15 Oil flow 16 Passage channel 17 Groove 18 Pin 19 Single part 20 Single part 21 Single part 22 Plunger 23 Emptying flapReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 3 746 278 B1

[0002]

Claims

Internal mixer (1) for rubber treatment, having a mixing chamber (2) and a rotor (4) for mixing a mixed material in the mixing chamber (2), wherein the rotor (4) has a rotor shaft (5) which is guided through a wall (3) of the mixing chamber (2), a first and second sealing component (6, 7) which are arranged in the region of the wall (3) around the rotor shaft (5) and are designed to seal the mixing chamber (2) outwards, wherein the first sealing component (6) rotates together on rotation of the rotor shaft and the second sealing component (7) does not rotate on rotation of the rotor shaft (5), wherein the first and / or second sealing component (6, 7) has a carrier part (11, 12) and a wear part (9, 10), wherein the wear part (9, 10) is designed to be replaced on wear, This does not require a complete replacement of the sealing component (6, 7).Internal mixer (1) according to Claim 1, in which the wear part (9, 10) and the associated carrier part (11, 12) are formed so as to be encircling the rotor shaft (5).Internal mixer (1) according to one of the preceding claims, in which the wear part (9, 10) is of annular design and the carrier part (11, 12) is of annular or sleeve-shaped design.Internal mixer (1) according to one of the preceding claims, in which the wear part (9, 10) is fastened to an end face of the carrier part (11, 12).Internal mixer (1) according to one of the preceding claims, in which the wear part (9, 10) is composed of a plurality of individual parts (19, 20, 21).Internal mixer (1) according to Claim 5, in which the individual parts (19, 20, 21) are each formed only partially encircling the rotor shaft (5) and the wear part (9, 10) extends completely around the rotor shaft.Internal mixer (1) according to one of the preceding claims, in which the wear part (9, 10) is designed to allow an oil flow through the wear part (9, 10).Internal mixer (1) according to one of the preceding claims, in which the wear part (9, 10) has one or more introduced through-channels (16) for permitting an oil flow (15).An internal mixer (1) according to any one of claims 7 or 8, wherein the wear member (9, 10) comprises a porous material for allowing oil flow (15).Internal mixer (1) according to one of the preceding claims, in which the wear part (9, 10) has a different material than the carrier part (11, 12).Internal mixer (1) according to one of the preceding claims, in which the wear part (9, 10) is arranged in a groove (17) of the carrier part.Internal mixer (1) according to one of the preceding claims, in which the wear part (9, 10) is fixed to the carrier part (11, 12) by means of a pin (18).Method for replacing components of an internal mixer (1) during wear, in which an internal mixer (1) according to one of the preceding claims is provided and the wear part (9, 10), but not the carrier part (11, 12), is replaced.Method according to claim 13, wherein the wearing part (9, 10) has a plurality of individual parts (19, 20, 21) and is disassembled into the individual parts (19, 20, 21) for replacement.

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