Process for producing a mixture by means of a horizontal tandem mixer

Abstract

The invention relates to a process for producing a mixture, in particular a rubber mixture, comprising the method steps of: a) introducing at least one starting material, in particular a rubber, and one or more further components into a first mixer (10) through a first inlet opening (12) and producing a pre-mixture, in particular a rubber pre-mixture, by mixing the components, b) transferring the pre-mixture from the first mixer (10) through a first outlet opening (14) into a first conveying unit (16), wherein the transfer takes place at least partially along the direction of gravitational force S and is at least partially brought about by gravitational force, c) conveying the pre-mixture by means of the first conveying unit (16) to a second inlet opening (18) of a second mixer (20), wherein the pre-mixture is transported by the first conveying unit (16) at least partially counter to the direction of gravitational force S, and d) processing the pre-mixture in the second mixer (20) to obtain a mixture, and discharging the mixture from the second mixer (20) through a second outlet opening (22), wherein the discharging operation takes place at least partially along the direction of gravitational force S and is at least partially brought about by gravitational force, wherein the first mixer (10) and the second mixer (20) are at least partially spaced apart from one another transversely to the direction of gravitational force S.

Description

[0001] Horizontal tandem mixer

[0002] Description

[0003] The invention relates to a method for producing a mixture, in particular a rubber mixture, and a subsequent method for producing a processed mixture, in particular a processed rubber mixture, as well as a mixer arrangement for use in a corresponding method and a mixer system based thereon.

[0004] With the advancing technological advancement, vehicle tires have evolved from relatively simple rubber products to highly complex ones. An important part of this progress is the development of modern production facilities for the manufacture of the rubber compounds required for vehicle tires. Modern vehicle tires are typically exposed to a wide variety of stresses during use, so the demands placed on rubber compounds for vehicle tires have steadily increased in recent decades. To meet these requirements, rubber compounds with increasingly complex compositions are being used, which, despite their increased complexity, must still be maintained with a high degree of homogeneity in the shortest possible time.

[0005] Manufacturing processes for mixtures are known from the prior art, which involve discontinuous or batch production of the mixture in several mixing steps and are suitable for the production of rubber compounds. The components relevant for the mixture are introduced, for example, into a mixer designed as an internal mixer. By repeatedly adding the mixed product to the same mixer at different temperatures and adding additional additives, the mixture is created after several mixing steps, which can be further processed in downstream processes.

[0006] However, this method is often perceived as disadvantageous, as repeated processing of the mixture in the same mixer, especially for rubber compounds, is inefficient both in terms of time and manual labor. Furthermore, returning the mixed product from the mixer outlet back to the inlet of the same mixer can be complex in terms of equipment, potentially resulting in avoidable logistical overhead within the production facility.

[0007] To simplify the process described above, so-called tandem mixing processes were developed. A tandem mixer usually comprises two mixers arranged one above the other, which, for example, cover different temperature ranges during the mixing process, thus eliminating the need to repeatedly feed the mixed product into the same mixer. Instead, the mixed product can be passed directly from the top mixer to the mixer below, allowing the mixture output from the lower mixer to be further processed in downstream processes.

[0008] However, the tandem mixing processes known from the state of the art are regularly considered inadequate or in need of improvement. Due to their large dimensions and usually considerable space requirements, they often place particularly high demands on the production facilities in which the tandem mixer is operated. This is perceived as a disadvantage in practice, particularly with regard to the required height of the production facility, as locally applicable building regulations can limit the installation height of tandem mixers in existing production facilities, making installation more difficult. Integration into existing production facilities is therefore often either not possible, necessitating the construction or purchase of new production facilities, or can only be achieved through complex conversion measures.Therefore, many rubber processing companies cannot easily switch from conventional mixing processes to tandem mixing processes, which can result in a loss of competitiveness.

[0009] The primary object of the present invention was to eliminate or at least reduce the above-described disadvantages of the prior art.

[0010] In particular, it was the object of the present invention to provide a process for producing a mixture, in particular a rubber mixture, with an optimized use of space, wherein in particular the space requirement of the devices required in the process to be specified should be reduced in the vertical direction compared to conventional tandem mixing processes.

[0011] It was also an object of the present invention that the method to be specified should be particularly time- and cost-efficient to carry out, wherein the efficiency should in particular be comparable to the efficiency of conventional tandem mixing methods.

[0012] Furthermore, it was an object of the present invention that the devices required in the method to be specified should be flexible in use and adaptable, so that the method to be specified should be easy to apply, in particular by conversion, to various existing mixing lines.

[0013] Furthermore, it was an object of the present invention to provide a process based on the corresponding method for producing a processed mixture, in particular a processed rubber mixture. Furthermore, it was an object of the present invention to provide a mixer arrangement for use in a corresponding process and a mixer system with a corresponding mixer arrangement. A desirable requirement here was that the specified mixer arrangement or mixer system should be easy to manufacture, in particular by converting and / or upgrading existing mixer arrangements or systems.

[0014] The inventors have now discovered that the above objects can surprisingly be achieved if the components to be processed into a mixture, in particular a rubber mixture, are mixed successively in at least two mixers arranged essentially horizontally to one another, provided that the transfer of the mixture between the mixers is achieved via at least one conveyor unit, as defined in the claims. In such a process, which combines the advantages of a so-called tandem mixing process with optimized space utilization, even complex mixtures, in particular rubber mixtures, can be produced particularly time- and cost-efficiently.

[0015] The above-mentioned objects are thus achieved by the subject matter of the invention as defined in the claims. Preferred embodiments of the invention emerge from the subclaims and the following statements.

[0016] Such embodiments, which are designated as preferred below, are combined in particularly preferred embodiments with features of other embodiments designated as preferred. Combinations of two or more of the embodiments designated as particularly preferred below are thus very particularly preferred. Likewise preferred are embodiments in which a feature of one embodiment designated as preferred to any extent is combined with one or more further features of other embodiments designated as preferred to any extent. Features of preferred mixer arrangements and mixer systems emerge from the features of preferred methods.

[0017] The invention relates to a process for producing a mixture, in particular a rubber mixture, comprising the

[0018] Method steps: a) introducing at least one starting material, in particular a rubber, and one or more further components into a first mixer through a first inlet opening and producing a premix, in particular a rubber premix, by mixing the components, b) transferring the premix from the first mixer through a first outlet opening into a first conveying unit, wherein the transfer takes place at least partially along the direction of gravity S and is at least partially effected by gravity, c) conveying the premix with the first conveying unit to a second inlet opening of a second mixer, wherein the premix is ​​conveyed by the first conveying unit at least partially against the direction of gravity S, and d) processing the premix in the second mixer to obtain a mixture and discharging the mixture from the second mixer through a second outlet opening,wherein the dispensing takes place at least partially along the direction of gravity S and is at least partially effected by gravity, wherein the first mixer and the second mixer are spaced apart from one another at least partially transversely to the direction of gravity S. The method according to the invention is suitable for producing mixtures, in particular conventional rubber mixtures, but also, for example, mixtures of other plastics. In the case of rubber mixtures, it is clear to the person skilled in the art that the term "rubber mixture" encompasses all mixtures that contain at least one rubber, wherein the rubber can be, for example, natural rubber or a synthetic rubber. The person skilled in the art understands that the method according to the invention is particularly preferably used for the production of rubber mixtures, so that for all embodiments, a method is particularly preferred wherein the mixture is a rubber mixture,wherein the starting material is rubber, and wherein the premix is ​​a rubber premix.,

[0019] In addition to the process steps described above, the mixture can be subjected to further processing steps during its production process. For example, it can be tempered in the first mixer and / or the second mixer and / or the first conveying unit. Alternatively or additionally, the chemical or physical properties of the mixture can be modified in one of the mixing stages or during transfer by adding additional components.

[0020] In process step a) of the process according to the invention, at least one starting material, in particular a rubber, and one or more further components are introduced into a first mixer. The amount and / or type of starting material or further components can be selected depending on the application requirements of the mixture. In particular, in the production of rubber mixtures, a process according to the invention is relevant for essentially all embodiments, wherein the further components are selected from the group consisting of fillers, plasticizers, and other additives, preferably selected from the group consisting of precipitated silicon dioxide, silane coupling agents, and plasticizers. In the first mixer, mixing the introduced components produces a mixture which, in the context of the present invention, is referred to as a premix and can, in particular, be a rubber premix.

[0021] With a view to a good applicability of the method according to the invention in existing mixing lines, that is to say in particular a good integrability of the devices used in the method, it has proven advantageous to provide a supply arrangement for the first mixer in order to introduce the components to be mixed in the desired content into the first mixer, since such supply arrangements are present in many cases in existing mixing lines and can be advantageously integrated into the method according to the invention.A method according to the invention is therefore preferred, wherein the at least one starting material and / or the further components are provided from a supply arrangement, wherein the supply arrangement comprises one or more storage containers and / or at least one conveying device, for example a conveyor belt for supplying the rubber, preferably several storage containers and a conveying device, wherein the supply arrangement is preferably arranged above the first mixer with respect to the direction of gravity S, wherein the introduction into the first mixer is particularly preferably effected at least partially by gravity.

[0022] The premix differs from the subsequently obtained mixture in that the premix is ​​essentially the output product of the first mixer, while the mixture according to the invention is obtained from the premix and is accordingly ready for further processing.

[0023] In process step b) of the process according to the invention, the premix obtained in the first mixer is transferred through a first outlet opening into a first conveying unit. According to the invention, the transfer takes place at least partially along the direction of gravity S and is effected at least partially by gravity.

[0024] In accordance with expert understanding, the direction of gravity S corresponds to the direction of the weight acting on the earth. Accordingly, a mixture moves along the direction of gravity S, for example from a mixer arranged in the factory hall, such that the mixture falls out of the mixer or moves towards the hall floor. This movement can occur solely due to the weight acting on the mixture, for example by the opening of an outlet hatch, or it can be additionally promoted, for example induced by being forced out of the mixer. In principle, however, the latter is also a movement caused at least partially by gravity, since gravity always acts on the earth regardless of any additional external force.The outlet movement can also be guided, for example, by a chute or ramp in such a way that the premix is ​​not discharged exclusively along the direction of gravity.

[0025] In process step c) of the method according to the invention, the premix is ​​conveyed by the first conveying unit to a second inlet opening of a second mixer. According to the invention, the conveying by the first conveying unit takes place at least partially counter to the direction of gravity S. Thus, the movement of the premix in process steps b) and c) initially occurs along and then counter to the direction of gravity S. In other words, the premix discharged from the bottom of the first mixer is conveyed back up by the conveying unit so that it can be fed into the second mixer from above.

[0026] By providing the conveying unit between the first and second mixers, they can advantageously be arranged horizontally offset from one another while still operating in a tandem mixer configuration. The intermediate use of the conveying unit also significantly increases the flexibility of the inventive method compared to the conventional tandem mixing method, as it makes it easier to integrate additional components, such as analytical devices. This makes the inventive method particularly easy to adapt to future developments.

[0027] According to the invention, the first mixer and the second mixer are at least partially spaced apart from one another transversely to the direction of gravity S. In practice, this means, in other words, that the first mixer and the second mixer are at least partially arranged side by side in the method according to the invention.

[0028] In process step d) of the process according to the invention, the premix is ​​processed in the second mixer to obtain the desired mixture. The mixture is discharged from the second mixer through a second outlet opening, again at least partially along the direction of gravity S, wherein the discharge is effected at least partially by gravity, as already described above.

[0029] Suitable mixers are known to the person skilled in the art based on their specialist knowledge. A typical method according to the invention is one in which the first mixer comprises a first mixing chamber with a first mixing unit arranged therein. A typical method according to the invention is one in which the second mixer comprises a second mixing chamber with a second mixing unit arranged therein.

[0030] The inventors have identified particularly preferred embodiments for the first mixer and the second mixer, which particularly advantageously complement the method according to the invention, particularly with regard to time- and cost-efficient process control. For the first mixer, so-called plunger mixers have proven advantageous in practice. A plunger mixer, sometimes also referred to as a plunger kneader, usually comprises a closed mixing chamber with at least two rotors, for example, operated in opposite directions, which are designed to mix one or more components fed into the plunger mixer. The mixing chamber of the plunger mixer is accessible via an inlet opening that can be closed with a plunger, wherein the plunger, for example, pneumatically and / or hydraulically forces the components fed into the mixing chamber through the rotors in order to achieve mixing of these components.Due to the combined action of the ram and rotors, the material being mixed is subjected to particularly high shear forces within the ram mixer. In this respect, high temperatures can also be achieved particularly effectively in ram mixers. A ramless mixer, on the other hand, which has proven particularly advantageous for the second mixer, can exert lower shear forces on the mixture due to the lack of a ram compared to a ram mixer, so that the mixture can be processed in the second mixer at lower temperatures. Accordingly, a method according to the invention is preferred wherein the first mixer is a ram mixer. Alternatively or additionally, a method according to the invention is preferred wherein the second mixer is a ramless mixer.

[0031] As explained above, the first mixer and the second mixer in most cases each comprise a mixing unit equipped with rotors for processing the mixture in the mixer. A method according to the invention is preferred, wherein the first mixing unit and / or the second mixing unit comprises two or more rotors, wherein the rotors are preferably tangential or intermeshing rotors. The term "tangential" in relation to the rotors means, in accordance with the expert understanding, that the outer rotor diameter essentially corresponds to the distance between the geometric centers of the rotors, so that while they come close to one another during rotation, no contact occurs. A rotor system comprising tangential rotors can accordingly be operated at different rotation speeds.In contrast, intermeshing rotors refer to systems in which the distance between the geometric centers of the rotors is smaller than the outer rotor diameter, so that the rotors must rotate independently of each other. Both tangential and intermeshing rotors can exert particularly high shear forces on the (pre)mixture fed into the mixing chamber. Due to their respective properties, tangential rotors have proven particularly advantageous in practice for high throughput, while intermeshing rotors demonstrate their advantages particularly in dispersive mixing, particularly with regard to excellent cooling performance.

[0032] The cooling capacity of mixers can be relevant when processing mixtures, especially when processing rubber mixtures, since individual components of mixtures can be temperature-sensitive, or individual components of rubber mixtures are temperature-sensitive. In practice, for example, it has proven advantageous for rubber mixtures to only add the temperature-sensitive components of the rubber mixture at low temperatures to prevent scorching of the rubber mixture. Thus, a method according to the invention is relevant for most cases, in which the premix is ​​mixed with additional components in the second mixer.

[0033] In order to cool the (pre)mixture in the process according to the invention after the first mixing process, it has proven advantageous in practice to make the mixing chamber volume of the second mixer larger than the mixing chamber volume of the first mixer. According to the inventors' assessment, the transfer of the premixture in the conveying unit can make a synergistic contribution to this. The larger surface area of ​​the mixing chamber in the second mixer compared to the first mixer promotes a reduction in the (pre)mixing temperature. Therefore, a process according to the invention is preferred in which the first mixing chamber has a larger volume than the second mixing chamber.

[0034] In principle, it is advantageous if the dispensing time and / or the dispensing quantity of mixed material from the first mixer and the second mixer can be controlled by the user of the method according to the invention, as can be achieved, for example, by closable flaps at the outlet openings. Accordingly, a method according to the invention is preferred in which automatically closable flaps are arranged at the first outlet opening and / or the second outlet opening, preferably at both outlet openings.

[0035] With a view to low equipment expenditure and easy integration of the devices used in the process according to the invention, it has proven advantageous to use gravity as the driving force for the input and output of the components or the (pre)mixture as far as possible, despite the horizontal arrangement. In this respect, the use of additional introduction devices and / or suction devices can be avoided in the process according to the invention by utilizing the force of weight. Accordingly, a process according to the invention is preferred in which the transfer of the premixture in process step b) takes place essentially entirely along the direction of gravity S, with the transfer preferably being effected essentially entirely by gravity.A method according to the invention is also preferred, wherein the dispensing of the mixture in method step d) takes place substantially entirely along the direction of gravity S, wherein the dispensing is preferably effected substantially entirely by gravity.

[0036] As explained above, the mixture obtained from the second mixer can then be further processed. The invention thus also relates to a method for producing a processed mixture, in particular a processed rubber mixture, comprising the method steps of the method according to the invention for producing a mixture, in particular a rubber mixture, and additionally the method steps: e) conveying the output mixture with a second conveying unit to a third inlet opening of a processing unit, wherein the mixture is conveyed by the second conveying unit at least partially against the direction of gravity S, and f) processing the mixture in the processing unit to obtain a processed mixture, wherein the second mixer and the processing unit are at least partially spaced from one another transversely to the direction of gravity S.

[0037] The process according to the invention is suitable for producing a processed mixture, in particular a processed rubber mixture, and comprises, in addition to process steps a) to d), conveying the mixture obtained from process step d) by means of a second conveying unit to a third inlet opening of a processing unit. The conveying takes place at least partially counter to the direction of gravity S.

[0038] In a further process step f), the mixture thus conveyed is processed in the processing unit according to the invention to obtain the processed mixture. In certain embodiments, the processed mixture can be further processed in downstream processes, for example, to achieve optimized storage of the processed mixture. For this purpose, further physical and / or chemical processes, such as cooling the processed mixture, shaping, or coating the processed mixture with additional components, can be carried out in such downstream processes.

[0039] According to the invention, the second mixer and the processing unit are also again at least partially spaced apart from each other transversely to the direction of gravity S. With regard to the relationships between the devices used in the method according to the invention, a method according to the invention is therefore typical for the vast majority of cases, wherein the first mixer and the processing unit are at least partially spaced apart from each other transversely to the direction of gravity S.

[0040] In practice, this means, for example, that a method according to the invention is conceivable, wherein the second mixer and the

[0041] Processing units are arranged at least partially next to each other, ie horizontally offset at the same height.

[0042] Advantageously, the method according to the invention is not limited with regard to the design of the processing unit. An example of a method according to the invention is one in which the processing unit is configured to mix the mixture with additional components and / or to shape the mixture.

[0043] In principle, the processing unit can be designed in different ways. For example, it can comprise an extruder, i.e. a conveying device which, using a conveying screw, continuously presses an input material through a shaping output opening using pressure and / or temperature in order to obtain an output material in a predetermined geometric shape. In the present case, the mixture is to be understood as the input material, wherein the processed mixture corresponds to the output material. An example is therefore a method according to the invention wherein the processing unit is an extruder. Additionally or alternatively, a method according to the invention is preferred wherein the processing unit comprises a shaping unit, wherein the shaping unit preferably comprises two or more rollers for shaping the mixture.

[0044] With regard to the production of mixtures, especially rubber mixtures, it is often advantageous to control the temperature during the production process in order to enable particularly efficient processing of the components. Accordingly, a method according to the invention is preferred, wherein the first mixer and / or the second mixer and / or the processing unit comprise means for temperature control.

[0045] In principle, it is considered an advantage of the method according to the invention that the conveyor units are not limited in their specific design, so that, for example, appropriately configured conveyor belts can be used. However, the inventors have succeeded in identifying conveyor unit designs that have been used in practice to achieve particularly efficient process control and, in particular, allow for reliable conveying of mixtures and premixes. Conveyor units that essentially belong to the group of discontinuous conveyors are preferred, meaning that the elements or mixtures transported by the conveyor units are not conveyed continuously, as would be the case with conveyor belts, for example.Accordingly, a method according to the invention is initially preferred, wherein the first conveyor unit and / or the second conveyor unit, preferably both conveyor units, are designed as discontinuous conveyors. Although it is fundamentally possible to provide trackless conveyor units in the method according to the invention, track-bound conveyor units are explicitly preferred, particularly since track-bound conveyor units enable particularly flexible, cost-effective, and efficient transport and can also be automated particularly well and safely.A method according to the invention is therefore preferred, wherein the first conveyor unit and / or the second conveyor unit, preferably both conveyor units, comprise a guide arrangement with at least one conveyor container, preferably exactly one conveyor container, wherein the guide arrangement preferably comprises rails for guiding the conveyor container, wherein the conveyor container is particularly preferably movable in the rails by means of wheels. In this implementation, a method according to the invention is expedient, wherein the premix is ​​transferred in process step b) from the first mixer into a conveyor container of the first conveyor unit. Analogously, a method according to the invention is expedient, wherein the mixture is discharged in process step d) from the second mixer into a conveyor container of the second conveyor unit.

[0046] The method according to the invention is advantageously particularly suitable for extensive automation. Therefore, a method according to the invention is also preferred, wherein the first conveyor unit and / or the second conveyor unit, preferably both conveyor units, are automated conveyor units.

[0047] The first conveyor unit and the second conveyor unit can advantageously be designed differently from one another, thus enabling individual adaptation to different structural conditions of factory halls, although preferably only the dimensions are varied. With regard to the production of the conveyor units, however, it is particularly preferred if the first conveyor unit and the second conveyor unit are designed essentially identically.

[0048] In particularly preferred embodiments, at least one of the conveyor units, preferably both conveyor units, comprises a tilting device. The tilting device can, for example, be designed as a mechanism which raises or lowers the conveyor container of the conveyor unit on one side in order to change the orientation of an opening of the conveyor container in space and thus empty the conveyor container so that the contents conveyed in the conveyor container can be discharged through the opening, for example into the second mixer. For example, the conveyor container can be tilted by at least 45°, preferably by at least 75°, particularly preferably by at least 90°, by means of the tilting device so that the orientation of the opening can be aligned both along the direction of gravity S and against the direction of gravity S.Accordingly, a method according to the invention is preferred, wherein the first and / or the second conveying unit, preferably both conveying units, comprise a tilting device which is designed to tilt the conveying container in the region of the second inlet opening or the third inlet opening such that the contents of the conveying container are introduced into the second mixer or into the processing device, wherein the introduction is preferably effected at least partially by gravity.

[0049] In principle, the process according to the invention can be used in various existing mixing lines after appropriate conversion, i.e. in particular arrangements of first mixers and second mixers as well as, if appropriate, processing units and further units that meet the requirements of the process according to the invention. In this respect, the conveyor units from conventional tandem mixers can be used to create mixing lines in which the devices in the mixing line are arranged next to one another, at least in sections. This means that they are arranged virtually along the horizon in a factory hall, so that less vertical space is required compared to the tandem mixing process. In practice, the devices used in the process according to the invention will in many cases have an inherent height in the range of 5 to 9 meters or will even be arranged on different floors.Accordingly, the inventors propose using the flexibility of the method according to the invention to, for example, bridge particularly large height differences between the devices. Accordingly, a method according to the invention is preferred, wherein the first outlet opening is arranged below the second inlet opening with respect to the direction of gravity S, wherein the distance along the direction of gravity S is preferably 1 m or more, particularly preferably 2 m or more, very particularly preferably 4 m or more, and / or wherein the second outlet opening is arranged below the third inlet opening with respect to the direction of gravity S, wherein the distance along the direction of gravity S is preferably 1 m or more, particularly preferably 2 m or more, very particularly preferably 4 m or more.

[0050] Accordingly, a method according to the invention is also preferred, wherein the premix is ​​conveyed by the first conveying unit against the direction of gravity S by 1 m or more, preferably 2 m or more, particularly preferably 4 m or more, very particularly preferably 6 m or more, and / or wherein the mixture is conveyed by the second conveying unit against the direction of gravity S by 1 m or more, preferably 2 m or more, particularly preferably 4 m or more, very particularly preferably 6 m or more. Therefore, a method according to the invention is also preferred, wherein the first and / or the second conveying unit, preferably both conveying units, comprise a lifting device which is designed to convey the conveying container at least partially against the direction of gravity S, preferably by 1 m or more, particularly preferably by 2 m or more, very particularly preferably by 4 m or more, wherein the lifting device preferably comprises an elevator system.

[0051] As explained above, one of the advantages of the method according to the invention can be seen in the fact that the mixture, the premix and the components comprised thereby can be transferred at least in sections by utilizing the force of gravity, despite a fundamentally horizontal arrangement of the mixing line. In this respect, the equipment expenditure can be minimized by avoiding the use of additional introduction devices and / or suction devices for the first mixer, the second mixer and the processing unit. A method according to the invention is therefore preferred, wherein the first conveying unit runs in sections below the first outlet opening and in sections above the second inlet opening with respect to the direction of gravity S, and / or wherein the second conveying unit runs in sections below the second outlet opening and in sections above the third inlet opening with respect to the direction of gravity S.

[0052] The person skilled in the art will understand that the invention further relates to a mixer arrangement, in particular for use in a method according to the invention, comprising: i) a first mixer with a first inlet opening and a first outlet opening, ii) a second mixer with a second inlet opening and a second outlet opening, and iii) a first conveying unit, wherein the mixer arrangement is designed so that a mixture produced in the first mixer can be transferred through the first outlet opening at least partially along an outlet direction A into the first conveying unit, wherein the first conveying unit is designed to convey the mixture transferred from the first mixer to the second inlet opening of the second mixer, wherein the mixture is conveyed by the first conveying unit at least partially counter to the outlet direction A, wherein the mixer arrangement is designedthat the mixture processed in the second mixer can be discharged through the second outlet opening at least partially along the outlet direction A, wherein the first mixer and the second mixer are at least partially spaced apart from each other transversely to the outlet direction A.,

[0053] The mixer arrangement according to the invention is particularly suitable for use in the process according to the invention. Particularly preferred are those mixer arrangements according to the invention that are suitable for preferred processes according to the invention.

[0054] A person skilled in the art will understand that the mixers in the mixer arrangement according to the invention and their arrangement relative to one another when defining the mixer arrangement, unlike in the method, occur freely in space and cannot be referred to the direction of gravity, which is why an alternative definition of the outlet direction A was made here as a reference system. In practice, however, the outlet direction A will essentially correspond to the direction of the weight acting on the earth, i.e. the direction of gravity S. Accordingly, a movement of a mixture along the outlet direction A, for example from a mixer arranged on a factory hall floor, can occur in such a way that it falls out of the mixer or moves towards the hall floor. This movement can, as described above, in turn be caused by the weight acting on the mixture.Therefore, a mixer arrangement according to the invention is relevant for essentially all embodiments, wherein the mixer arrangement is provided such that the outlet direction A corresponds at least partially, preferably substantially completely, to the direction of gravity S during operation. The invention further relates to a mixer system, in particular for use in a method according to the invention, comprising a mixer arrangement according to the invention and: iv) a processing unit with a third inlet opening, and v) a second conveying unit, wherein the second conveying unit is designed to convey the mixture discharged by the second mixer to the third inlet opening of the processing unit, wherein the mixture is conveyed by the second conveying unit at least partially counter to the outlet direction A, wherein the second mixer and the processing unit are at least partially spaced from one another transversely to the outlet direction A.

[0055] In accordance with the understanding of the person skilled in the art, particularly those mixer systems are preferred which are suitable for preferred processes according to the invention.

[0056] A mixer system according to the invention is therefore preferred, wherein the mixer system comprises a supply arrangement, wherein the supply arrangement comprises one or more storage containers and / or at least one conveying device for conveying a starting material, wherein the supply arrangement is preferably arranged on the side of the first mixer on which the first inlet opening is located.

[0057] Accordingly, a mixer system according to the invention is also preferred, wherein the first outlet opening is arranged below the second inlet opening with respect to the outlet direction A, wherein the distance along the outlet direction A is preferably 1 m or more, particularly preferably 2 m or more, very particularly preferably 4 m or more. A mixer arrangement according to the invention is also preferred, wherein the second outlet opening is arranged below the third inlet opening with respect to the outlet direction A, wherein the distance along the outlet direction A is preferably 1 m or more, particularly preferably 2 m or more, very particularly preferably 4 m or more.

[0058] A mixer system according to the invention is also preferred, wherein the first and / or the second conveyor unit, preferably both conveyor units, comprise a lifting device which is designed to convey the conveyor container at least partially counter to the outlet direction A, preferably by 1 m or more, particularly preferably by 2 m or more, very particularly preferably by 4 m or more, wherein the lifting device preferably comprises an elevator system.

[0059] Furthermore, a mixer system according to the invention is preferred, wherein the first conveying unit is arranged such that, with respect to the outlet direction A, it runs partially below the first outlet opening and partially above the second inlet opening. Alternatively or additionally, a mixer arrangement according to the invention is preferred, wherein the second conveying unit is arranged such that, with respect to the outlet direction A, it runs partially below the second outlet opening and partially above the third inlet opening.

[0060] Preferred embodiments of the invention are explained and described in more detail below with reference to the accompanying figures and using the example of a process for producing a rubber mixture. In the figures:

[0061] Fig. 1 is a schematic representation of a tandem mixing system not according to the invention; Fig. 2 is a schematic representation of a

[0062] Mixer system for use in a process according to the invention in a preferred embodiment; and

[0063] Fig. 3 is a schematic representation of a conveyor unit at different process times of the process according to the invention.

[0064] Fig. 1 shows a schematic representation of a tandem mixing system suitable for producing a processed rubber mixture. The tandem mixing system shown comprises a first mixer 10, a second mixer 20, and a processing unit 28, which are arranged vertically one above the other. The components necessary for producing a processed rubber mixture can be supplied to the tandem mixing system shown in the required quantity via a supply arrangement comprising several storage containers 38 and a separate conveyor device 40, which is arranged above the first mixer 10.Due to the arrangement of the first mixer 10 above the second mixer 20 and the arrangement of the second mixer 20 above at least parts of the processing unit 28, the use of the tandem mixing system shown requires a large amount of vertical space, i.e., along the direction of gravity S shown as an arrow. In practice, this requires production facilities with great heights, for example, with a height of more than 10 m, particularly considering the dimensions of the individual components of the tandem mixing system.

[0065] Fig. 2 now shows a preferred embodiment of a mixer system according to the invention. The mixer system shown comprises a first mixer 10, a second mixer 20, and a processing unit 28, spaced apart from one another transversely to the direction of gravity S represented by the directional arrow, i.e., arranged side by side. Similar to the tandem mixing system of Fig. 1, the mixer system also comprises a supply arrangement arranged above the first mixer 10, which includes a plurality of storage containers 38 and a conveyor device 40. As shown in the schematic illustration, however, due to the horizontal arrangement of the devices, the mixer system shown only requires approximately 60% of the height required for the tandem mixing system, despite the supply arrangement. In this respect, the mixer system shown can be used in production facilities with lower heights than the tandem mixing system of Fig. 1.

[0066] The mixer system shown comprises a first conveyor unit 16 and a second conveyor unit 24, which each convey the mixture discharged from the first mixer 10 or the second mixer 20 to the second mixer 20 or to the processing unit 28. When used in a method according to the invention for producing a processed rubber mixture, in the example shown, the components required for the rubber premix are fed into the first mixer 10 via a first inlet opening 12 by means of the supply arrangement, and the rubber premix is ​​produced in the first mixer 10. This is discharged into the first conveyor unit 16 via a first outlet opening 14 provided with an automatic flap, so that the rubber premix falls, due to gravity, from the first mixer 10 into a conveyor container 32 of the first conveyor unit 16, which runs below the first outlet opening 14, and in Fig.2 is shown in two positions, namely the loading and unloading position.

[0067] In the example shown in Fig. 2, the first conveyor unit 16 and the second conveyor unit 24 can be designed as automated discontinuous conveyors, as shown in Figs. 3a) to 3c). The discontinuous conveyor shown in Fig. 3a) comprises a guide arrangement 30, which receives the produced rubber (pre)mixture in the conveyor container 32. As shown in Fig. 3b), after being received, the rubber (pre)mixture is transported via rails 34a, 34b with the aid of a lifting device 36 designed as an elevator system to the respectively higher inlet opening, which in the example shown is located approximately 9 m above the outlet opening. Via a tilting mechanism, the rubber (pre)mixture is discharged into the inlet opening, as shown in Fig. 3c), for example by rotating the conveyor container about an axis, as indicated schematically in Fig. 2.

[0068] When used in a method according to the invention, the first conveyor unit 16 of Fig. 2 would accordingly transport the material to be conveyed, i.e., the rubber premix, from the first outlet opening 14 of the first mixer 10 to the second inlet opening 18 of the second mixer 20 and discharge it there by tilting the conveyor container 32 in order to produce a rubber mixture from the rubber premix in the second mixer 20. This can be achieved not only by cooling and mixing the rubber premix but also by adding further components, for example, chemicals that crosslink the rubber mixture.

[0069] When used in the method according to the invention, the rubber mixture in the example shown can then fall through a second outlet opening 22 provided with an automatic outlet flap into the conveyor container 32 of the second conveyor unit 24 arranged below the second outlet opening 22 and be transported to a third inlet opening 26 of the processing unit 28, where it is processed into a finished rubber mixture, for example, by molding the rubber mixture. For this purpose, the processing unit 28 shown comprises an extruder.

[0070] The first mixer 10 and the second mixer 20 each comprise a mixing chamber for processing the components of the rubber mixture or the rubber premix, respectively. The mixing chamber has at least two, for example, intermeshing, rotors. The first mixer 10 additionally has a ram designed to convey the mixture through the rotors under pressure. Furthermore, the volume of the mixing chamber of the first mixer 10 in the example shown is larger than the volume of the mixing chamber of the second mixer 20, so that a temperature gradient can be established between the mixing chambers. Therefore, the rubber premix in the second mixer 20 has a lower temperature during processing than the rubber premix exiting the first mixer 10. This temperature gradient can also be adjusted by temperature control means in the mixers and optionally also supported by temperature control of the conveying containers 32.

[0071] List of reference symbols

[0072] 10 first mixer

[0073] 12 first inlet opening

[0074] 14 first outlet opening

[0075] 16 first conveyor unit

[0076] 18 second inlet opening

[0077] 20 second mixer

[0078] 22 second outlet opening

[0079] 24 second conveyor unit

[0080] 26 third inlet opening

[0081] 28 processing unit

[0082] 30 Guide arrangement

[0083] 32 conveyor container

[0084] 34a-b rails

[0085] 36 Lifting device

[0086] 38 storage containers

[0087] 40 conveyor system

[0088] S direction of gravity

[0089] A Outlet direction

Claims

Claims 1. A method for producing a mixture, comprising the method steps: a) introducing at least one starting material and one or more further components into a first mixer (10) through a first inlet opening (12) and producing a premix by mixing the components, b) transferring the premix from the first mixer (10) through a first outlet opening (14) into a first conveyor unit (16), wherein the transfer takes place at least partially along the direction of gravity S and is at least partially effected by gravity, c) conveying the premix with the first conveyor unit (16) to a second inlet opening (18) of a second mixer (20), wherein the premix is ​​conveyed by the first conveyor unit (16) at least partially against the direction of gravity S,and d) processing the premix in the second mixer (20) to obtain a mixture and discharging the mixture from the second mixer (20) through a second outlet opening (22), wherein the discharging takes place at least partially along the direction of gravity S and is at least partially caused by gravity, wherein the first mixer (10) and the second mixer (20) are at least partially spaced from each other transversely to the direction of gravity S.

2. A process for producing a processed mixture, comprising the process steps of the process according to claim 1, and additionally the process steps: e) conveying the dispensed mixture with a second conveying unit (24) to a third inlet opening (26) of a processing unit (28), wherein the mixture is conveyed by the second conveying unit (24) at least partially counter to the direction of gravity S, and f) processing the mixture in the processing unit (28) to obtain a processed mixture, wherein the second mixer (20) and the processing unit (28) are at least partially spaced from one another transversely to the direction of gravity S.

3. Method according to one of claims 1 or 2, wherein the first outlet opening (14) is arranged below the second inlet opening (18) with respect to the direction of gravity S, and / or wherein the second outlet opening (22) is arranged below the third inlet opening (26) with respect to the direction of gravity S.

4. Method according to one of claims 1 to 3, wherein the first conveyor unit (16) extends in sections below the first outlet opening (14) and in sections above the second inlet opening (18) with respect to the direction of gravity S, and / or wherein the second conveyor unit (24) extends in sections below the second outlet opening (22) and in sections above the third inlet opening (26) with respect to the direction of gravity S.

5. The method according to any one of claims 1 to 4, wherein the transfer of the premix in process step b) takes place substantially entirely along the direction of gravity S, and / or wherein the dispensing the mixing in process step d) takes place essentially entirely along the direction of gravity S.

6. The method according to any one of claims 1 to 5, wherein the first mixer (10) is a stamp mixer, and / or wherein the second mixer (20) is a stampless mixer.

7. Method according to one of claims 1 to 6, wherein the first conveyor unit (16) and / or the second conveyor unit (24) comprise a guide arrangement (30) with at least one conveyor container (32).

8. Method according to one of claims 1 to 7, wherein the first conveyor unit (16) and / or the second conveyor unit (24) comprise a lifting device (36) which is designed to convey the conveyor container (32) at least partially counter to the direction of gravity S.

9. Mixer arrangement, in particular for use in a method according to one of claims 1 to 8, comprising: i) a first mixer (10) with a first inlet opening (12) and a first outlet opening (14), ii) a second mixer (20) with a second inlet opening (18) and a second outlet opening (22), and iii) a first conveyor unit (16), wherein the mixer arrangement is designed so that a mixture produced in the first mixer (10) can be transferred through the first outlet opening (14) at least partially along an outlet direction A into the first conveying unit (16), wherein the first conveying unit (16) is designed to convey the mixture transferred from the first mixer (10) to the second inlet opening (18) of the second mixer (20), wherein the mixture is conveyed by the first conveying unit (16) at least partially counter to the outlet direction A, wherein the mixer arrangement is designed so that the mixture processed in the second mixer (20) can be discharged through the second outlet opening (22) at least partially along the outlet direction A, wherein the first mixer (10) and the second mixer (20) are at least partially spaced from one another transversely to the outlet direction A.

10. Mixer system, in particular for use in a method according to one of claims 1 to 8, comprising a mixer arrangement according to claim 9 and: iv) a processing unit (28) with a third inlet opening (26), and v) a second conveying unit (24), wherein the second conveying unit (24) is designed to convey the mixture discharged by the second mixer (20) to the third inlet opening (26) of the processing unit (28), wherein the mixture is conveyed by the second conveying unit (24) at least partially counter to the outlet direction A, wherein the second mixer (20) and the processing unit (28) are at least partially spaced apart from one another transversely to the outlet direction A.

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