Mixing device for mixing rubber mixtures with a mixing chamber and a saddle and a method for cleaning a saddle of the mixing device

Abstract

Mixing device (2) for mixing rubber mixtures, - with a mixing chamber (9) which is delimited by a chamber housing (1), a filling opening (5) and an ejection opening (8), and - with a saddle (12) which is adjustable for opening and closing the ejection opening (8), the side walls (3, 4) of which, in the closed state, are in contact with the side walls (6, 7) of the ejection opening (8), characterized in that - the mixing device (2) has one or more removal devices (14, 16, 20) which are provided for removing at least part of a rubber mixture which adheres to the side walls (3, 4) of the saddle (12) or to the side walls (6, 7) of the ejection opening (8) from the side walls (3, 4) of the saddle (12) or the side walls (6, 7) of the ejection opening (8).

Description

[0001] The invention relates to a mixing device for mixing rubber mixtures, comprising a mixing chamber defined by a chamber housing, a filling opening, and an ejection opening, and comprising a saddle adjustable for opening and closing the ejection opening, the side walls of which are in contact with the side walls of the ejection opening when closed. The invention also relates to a method for cleaning a saddle of the mixing device.

[0002] In the rubber industry, various types of mixers are often used to blend rubber and other components into a rubber compound. The resulting rubber compound often has an unfavorable consistency, making it difficult to eject the rubber compound from the mixer in question. Often, pieces of the rubber compound stick to the side walls of the discharge opening or the saddle, making it difficult or even impossible to close the saddle, rendering the mixer unusable until further notice.

[0003] Various saddle designs are known in the state of the art:

[0004] EP 0 845 292 A1 discloses an internal mixer with “an outlet saddle movable beneath the rotors substantially centrally between the rotors [...] for opening and closing the chamber housing” (see claim 1).

[0005] US 3 135 440 A discloses a mechanically driven door of a mixer and a mechanical drive mechanism which allows the material to be discharged from the mixing chamber of the mixer.

[0006] CN 2 08 801 482 U discloses a mixer with automatic cooling and cleaning function from the field of mixing technology for classified materials, which mixer comprises a mixing chamber, a mixing roller and a mixer body, which further comprises at least two cleaning nozzles, at least two cooling nozzles and a wind mode control unit, wherein the cleaning nozzles and the cooling nozzles are each arranged on both sides of the working chamber, the openings of the cleaning nozzles and cooling nozzles are aligned towards the working chamber, the cooling nozzles are arranged below the cleaning nozzles and the wind mode control unit controls the cleaning nozzles and cooling nozzles.

[0007] The CN 2 03 957 186 U discloses an internal mixer with unloading and cleaning function via coupling.

[0008] JP 2003-144 884 A discloses a device for cleaning a kneading machine when changing the material to be kneaded.

[0009] Furthermore, JP H09-29 088 A describes the provision of a device for mixing powder particles, which is automatically subjected to effective cleaning within a short time and carries out an economical and efficient filter treatment during the treatment of various powder particles.

[0010] An object underlying the invention is to provide a mixing device for mixing rubber mixtures in which disturbances during the closing of the saddle are reduced or avoided compared to the prior art.

[0011] This object is achieved according to the invention by a mixing device for mixing rubber mixtures, - with a mixing chamber which is delimited by a chamber housing, a filling opening and an ejection opening, and - with a saddle which is adjustable for opening and closing the ejection opening, the side walls of which are in contact with the side walls of the ejection opening when closed, characterized in that - the mixing device comprises one or more removal devices which are intended to remove at least part of a rubber mixture adhering to the side walls of the saddle or to the side walls of the ejection opening from the side walls of the saddle or the side walls of the ejection opening.

[0012] Preferably, the one or more removal devices are provided to remove more than 70 wt.%, particularly preferably more than 90 wt.%, most particularly preferably more than 95 wt.%, of the total rubber mixture adhering to the side walls of the saddle or to the side walls of the ejection opening from the side walls of the saddle or the side walls of the ejection opening.

[0013] In addition, the mixing device according to the invention for mixing rubber mixtures can also comprise 1, 2, 3 or more than 3 further mixing chambers and / or 1, 2, 3 or more than 3 further saddles.

[0014] By installing one or more removal devices, such as gas nozzles or movable brushes, in a mixing device according to the invention, it is possible to remove rubber mixture that has stuck to the side walls of the ejection opening or the saddle. This ensures proper closure of the saddle after the mixed rubber mixture has been ejected. This can prevent production downtime.

[0015] Within the scope of the present invention, the saddle described above can be a folding saddle or a sliding saddle. Both saddle types can be opened and closed using a hydraulic system.

[0016] Problems caused by adhering rubber compounds arise with sliding saddles, particularly from rubber compounds that adhere to the side wall of the ejection opening or the sliding saddle, which first separate from each other. The adhering rubber compound prevents the sliding saddle from subsequently closing completely. Similar problems can also occur on the side walls of the ejection opening or the sliding saddle that run parallel to the sliding saddle's sliding direction.

[0017] Problems caused by adhering rubber compounds arise in particular from rubber compounds adhering to the side wall of the ejection opening, to which the hinge of the folding saddle is attached. However, rubber compound residues adhering to the hinge side wall of the folding saddle can also prevent the folding saddle from closing completely. In a mixing device according to the invention, the saddle is preferably a folding saddle.

[0018] In the context of the present invention, a mixing device is preferably an internal mixer, preferably a tandem mixer, particularly preferably an upper chamber of a tandem mixer or a lower chamber of a tandem mixer. In tandem mixers, the problems described above occur particularly frequently in the upper mixing chamber, which is intended for dispersing the various components of the rubber mixture. During dispersion of the individual components, they are reduced in size and wetted on the surface with the liquid components of the rubber mixture. The resulting rubber mixture usually has a relatively low Mooney viscosity at 25°C in the range of 5 to 100 MU, preferably in a range of 10 to 30 MU. The results were determined based on the ASTM D1646 method at 100°C using a Mooney viscometer in ML1+3 mode. The rotation speed of the stirrer was preferably 2 rpm.

[0019] When the saddle is opened, the individual components of the rubber compound usually do not fall in a trickle, but rather gradually fall out of the mixing chamber due to the adhesion of rubber compound residues from various parts of the mixing chamber, particularly from the side walls of the mixing chamber. Due to the behavior of the rubber compound described above, residues of the rubber compound remain on the side walls of the ejection opening and the saddle. In some cases, it may be useful to use a sealing material or similar between the side wall of the ejection opening and the side wall of the saddle, which rests against the saddle when the saddle is closed. This allows the ejection opening to be closed seamlessly.

[0020] It is understood that in these cases parts of the rubber mixture do not adhere to the side walls but to the corresponding sealing materials and must be removed by the one or more removal devices within the scope of the invention.

[0021] A mixing device as described above or as described above as preferred is preferred, characterized in that rubber mixtures are mixed which comprise at least one material selected from the group consisting of: fillers, liquid polymers, resins, and functionalized polymers. This applies in particular to rubber mixtures which contain silica as a filler, and even more so to rubber mixtures which contain silica and liquid polymers or silica and resins or silica and functionalized polymers. Within the scope of the present invention, functionalized polymers are preferably those polymers whose functional groups have been modified by at least one chemical reaction.

[0022] Particularly preferred is a mixing device as described above or as described above as preferred, characterized in that rubber mixtures are mixed which have 50 wt. % or less of solid rubbers, preferably 40 wt. % or less, particularly preferably 30 wt. % or less, very particularly preferably 25 wt. % or less. For the purposes of the present invention, solid rubbers are those rubbers which have a Mooney viscosity at 25°C of at least 20 MU, preferably of at least 30 MU, particularly preferably of at least 50 MU, very particularly preferably of at least 80 MU. The results were determined in accordance with the ASTM D1646 method at 100°C using a Mooney viscometer in ML1+3 mode. The rotation speed of the stirrer was preferably 2 rpm.

[0023] A mixing device as described above or as described above as preferred is preferred, characterized in that the saddle is a folding saddle with a hinge comprising two hinge bushings, wherein the hinge is functionally attached to a side wall of the saddle by the first hinge bushing and to a side wall of the discharge opening by the second hinge bushing. The hinge preferably has a hinge axis with a diameter in the range of 1 cm to 30 cm.

[0024] In the context of the present invention, hinge bushings are the strips attached to the hinge cylinder which are used to fasten the hinge to the respective side wall. The hinge of a folding saddle can often only be opened up to an angle of 90°, which creates an opening in which the rubber mixture to be ejected particularly often adheres. It is therefore particularly advantageous to install the one or more removal devices in the mixing device according to the invention in such a way that the above-described opening can be freed of residues of a rubber mixture which adheres to the side walls of the saddle or to the side walls of the ejection opening. This applies in particular to internal mixers and very particularly to tandem mixers, in particular to the upper mixing chamber of the tandem mixer.

[0025] A mixing device as described above or as described above as preferred or particularly preferred is preferred, characterized in that the or at least one of the plurality of removal devices has two planar outer surfaces, wherein the angle between the two planar outer surfaces corresponds approximately to the angle formed by the two hinge bushings of the hinge of the folding saddle in the open state. The removal device described above is preferably in the shape of a prism, in particular a tetragonal or pentagonal prism. When the saddle is in the open state, the removal device described above is preferably moved along the hinge axis with the pointed edge of the two planar outer surfaces so that residues of the rubber mixture can be removed as efficiently as possible.

[0026] In the context of the present invention, the expression "approximately corresponds to the angle" means that the angle of the two planar outer surfaces of the removal device corresponds to the angle formed between the hinge side wall of the ejection opening and the hinge side wall of the saddle, with a maximum deviation of a maximum of 10°, preferably a maximum of 5°.

[0027] A removal device as described above has the advantage that it can be moved across the gap between the saddle and the hinge side wall of the ejection opening in the direction of the hinge axis. This can be done in particular in an automated manner, thus allowing adhering residues of a rubber mixture to be removed. The outer surface of the removal device described above can have bristles or devices functionally similar to bristles to optimize the stripping of adhering residues of the rubber mixture.

[0028] In the context of the present invention, the term “hinge side wall” means the side wall of the saddle or the ejection opening to which a hinge bushing of the hinge is attached.

[0029] A mixing device as described above or as described above as preferred or particularly preferred is preferred, characterized in that the or at least one of the plurality of removal devices has one or more outer surfaces on a concave side of the one or at least one of the plurality of removal devices, wherein - at least one cross-section, preferably all cross-sections of the one or at least one of the plurality of outer surfaces along a first direction and parallel to a second direction perpendicular to the first direction represents a straight line and - At least one cross-section, preferably all cross-sections of the one or at least one of the plurality of outer surfaces along the second direction and perpendicular to the first direction, represents the circumferential profile of a cross-section of the saddle, wherein the cross-sectional plane of the cross-section of the saddle for the circumferential profile runs perpendicular to the hinge axis of the hinge and preferably through the center of the end face of the saddle. The saddle is preferably a folding saddle.

[0030] The removal device described above is moved with the outer surface along the front surface of the saddle when the saddle is open so that residues of the rubber mixture can be removed as efficiently as possible.

[0031] A removal device as described above has the advantage that it can be moved over the saddle in the direction of the hinge axis. This can be done in particular in an automated manner, thus allowing adhering residues of a rubber mixture to be removed. The outer surface on the concave side of the removal device described above can have bristles or devices functionally similar to bristles to optimize the removal of adhering residues of the rubber mixture.

[0032] In the context of the present invention, the term “circumferential profile” preferably refers only to the circumferential profile of the saddle, wherein only the circumference of the end face, the hinge side wall and the side wall opposite the hinge side wall are depicted.

[0033] Particularly preferred is a mixing device as described above or as described above as preferred or particularly preferred, characterized in that the one or more removal devices are one or more brushes. In addition to their excellent cleaning effect, an advantage of using brushes is that removal takes place in a mechanical manner in which the surfaces of the end face of the saddle and all cleaned side walls are protected. Within the scope of the invention, brush rollers or flat brushes are preferably used, but in particular brush rollers which can be guided in rotation over the surfaces described above in order to remove adhering residues of a rubber mixture. The width of the brush, in particular the width of the brush rollers, corresponds at least to the width of the saddle, wherein the width of the saddle is measured on a side which is parallel to the hinge axis.

[0034] A mixing device as described above as preferred is particularly preferred, characterized in that the one or at least one of the several removal devices is a brush, wherein the one brush - is mounted on an inside side wall of the shaft at a predetermined distance from the discharge opening and - is adapted to move, when the saddle is open, both over the side walls and the end face of the saddle and over the hinged side wall of the ejection opening, so that at least a portion of a rubber mixture adhering to the side walls of the saddle or to the hinged side wall of the ejection opening is removed from the side walls of the saddle or the hinged side wall of the ejection opening. Preferably, the one or more removal devices are provided for removing the entire rubber mixture adhering to the side walls of the saddle or to the hinged side wall of the ejection opening from the side walls of the saddle or the hinged side wall of the ejection opening.

[0035] Within the scope of the present invention, the one or at least one of the plurality of brushes is mounted on the side wall of the shaft, on which the hinge also lies. The distance between the hinge and the one or at least one of the plurality of brushes, while the saddle is closed, is preferably large enough that the saddle can be opened easily if necessary, but particularly preferably at least as large as the shortest measurable distance between the side wall of the shaft to which the one or at least one of the plurality of brushes is mounted and the opposite side wall of the shaft.

[0036] With the above-described arrangement of the removal device, in particular the brushes, the saddle can be opened without any problem and at the same time the brush is located directly at the point where it will later be needed to remove adhering residues of the rubber mixture.

[0037] A mixing device as described above as particularly preferred or very particularly preferred is also very preferably provided, characterized in that a second brush is attached to the inner side wall of the shaft opposite the hinge and is suitable for moving along the side wall of the ejection opening opposite the hinge, so that at least a portion of a rubber mixture adhering to the side wall of the ejection opening opposite the hinge is removed from the side walls of the ejection opening. Preferably, the one or more removal devices are provided for removing all of the rubber mixture adhering to the side walls of the saddle or to the side walls of the ejection opening from the side walls of the saddle or the side walls of the ejection opening.

[0038] One advantage of using a second brush is that the corresponding sidewalls can be cleaned more quickly of adhering residues of a rubber compound. The use of a third, fourth, or more than four brushes is therefore even more advantageous.

[0039] A mixing device as described above or as described above as preferred or particularly preferred is preferred, characterized in that the part of the one or more removal devices which comes into contact with a side wall of the saddle or the ejection opening during the removal of said part of a rubber mixture comprises or consists of a material selected from the group consisting of: - metal, - Thermosets and - Thermoplastics.

[0040] The use of brass or thermosets is preferred, as these materials are relatively soft and can withstand very high temperatures, which can occur on the various side walls. Brass is particularly preferred because any brass particles remaining in the rubber compound can be detected and removed later.

[0041] The use of thermoplastics has the advantage that they can usually remain in the rubber mixture without significant disadvantages and do not interfere with further production. Thermoplastics such as PE-HD, PP (polypropylene) or copolymers containing polypropylene monomer units are particularly preferred, especially PE-HD and PP. PE-HD stands for polyethylene, which has weakly branched polymer chains and, as a mixture, a high density of between 0.94 g / cm 3 and 0.97 g / cm 3 has.

[0042] A mixing device as described above or as described above as preferred or particularly preferred is preferred, characterized in that the one or more removal devices are one or more gas nozzles which are arranged in at least one side wall of the saddle, preferably both side walls of the saddle, and / or in at least one side wall of the ejection opening, so that the gas coming from the nozzles removes at least part of a rubber mixture adhering to the side walls of the saddle or to the side walls of the ejection opening, from the side walls of the saddle or the side walls of the ejection opening.

[0043] The use of gas nozzles has the advantage that the corresponding sidewalls are cooled immediately and the adhering rubber compound residues are removed without damaging the surface of the sidewalls. These nozzles are preferably located exclusively in the sidewalls of the saddle or the ejection opening.

[0044] However, it is also conceivable that the removal device is a mobile gas nozzle and is moved over the saddle and the side walls of the ejection opening as described above for the brush roller in order to remove adhering residues of a rubber mixture.

[0045] Also preferred is a mixing device as described above or as described above as preferred or particularly preferred, characterized in that the mixing device additionally comprises: - one, two or more than two rotors arranged substantially parallel to each other in the mixing chamber, where - the filling opening is located substantially above the rotors and the ejection opening is located substantially below the rotors and - an adjustable plunger for opening and closing the filling opening.

[0046] The embodiment described above preferably applies to tandem mixers, particularly preferably to the upper mixing chamber of a tandem mixer, since the plunger increases the shear forces during dispersion.

[0047] A mixing device as described above is preferred, in particular a mixing device with rotors described above as particularly preferred, characterized in that the hinge has a hinge axis with a diameter in the range of 1 cm to 30 cm, preferably in the range of 10 to 30 cm, particularly preferably in the range of 20 to 30 cm. The larger the diameter of the hinge axis, the larger the resulting opening between the hinge side wall of the discharge opening and the hinge side wall of the saddle.

[0048] In the context of the present invention, the hinge preferably has a continuous hinge axis, since an additional gap between a split hinge axis can lead to additional problems due to adhering residues of a rubber mixture. The hinge axis is preferably parallel to the rotor axis of one of the rotors, as described above, since this ensures that as little as possible of the mixed rubber mixture falls into the gap between the hinge side wall of the saddle and the hinge side wall of the ejection opening when the saddle is opened.

[0049] A mixing device as described above or as described above as preferred or particularly preferred is preferred, characterized in that the saddle end face facing the mixing chamber in the closed state of the saddle is designed in such a shape that - the saddle face is flush with the inner side wall of the chamber housing and - the saddle face transitions from the hinge side wall and the opposite side wall of the saddle into a concave area towards the centre of the saddle, whereby the two concave areas merge into one another in the centre of the saddle face in the form of a convex rounding directed towards the mixing chamber.

[0050] A mixing device as described above is preferred, in particular a mixing device with a saddle shape as described above, characterized in that the or at least one of the plurality of removal devices has one or more outer surfaces on a concave side of the one or at least one of the plurality of removal devices, wherein at least one cross section, preferably all cross sections of the one or at least one of the plurality of outer surfaces in a first direction along the outer surface represents a straight line and at least one cross section, preferably all cross sections of the one or at least one of the plurality of outer surfaces along a second direction perpendicular to the first direction represents the circumferential profile of a cross section of the folding saddle,The cross-sectional plane of the folding saddle cross-section for the peripheral profile is perpendicular to the hinge axis of the folding saddle and preferably passes through the center of the saddle's end face. Such a removal device has the advantages described above.

[0051] Most preferred is a mixing device as described above - with a mixing chamber which is bounded by a chamber housing, a filling opening and an ejection opening, - with a saddle which is adjustable for opening and closing the ejection opening, the side walls of which are in contact with the side walls of the ejection opening when closed, characterized in that the mixing device comprises one or more removal devices which are intended to remove at least part of a rubber mixture adhering to the side walls of the saddle or to the side walls of the ejection opening from the side walls of the saddle or the side walls of the ejection opening and the saddle is a folding saddle with a hinge comprising two hinge bushings, the first hinge bushing being attached to a side wall of the saddle and the second hinge bushing being attached to a side wall of the ejection opening, where - one of the plurality of removal devices is one or more gas nozzles arranged in at least one side wall of the saddle and / or in at least one side wall of the ejection opening, so that the gas coming from the nozzles removes at least part of a rubber mixture adhering to the side walls of the saddle or to the side walls of the ejection opening, from the side walls of the saddle or the side walls of the ejection opening, and / or - that the one or at least one of the plurality of removal devices is a brush roller, wherein the one brush - on an inside side wall of the shaft at a predetermined distance from the ejection opening and - is capable of moving both over the side walls and the front face of the saddle in the open position and over the hinged side wall of the ejection opening, all the rubber compound adhering to the side walls of the saddle or to the hinged side walls of the ejection opening is removed from the side walls of the saddle or the side walls of the ejection opening.

[0052] The invention also relates to methods for cleaning a saddle of a mixing device as described above or as described above as preferred or particularly preferred, the method comprising the following steps: a) Mixing a rubber mixture in a mixing chamber of the mixing device, preferably a rubber mixture as described above or as described above for a mixing device described as preferred, b) Ejecting the mixed rubber mixture through the ejection opening of the mixing device, and c) Removing at least part of the portion of the rubber mixture adhering to the side walls from the side walls of the saddle or the side walls of the ejection opening by means of the one or more removal devices. Mixing of the rubber mixture in step a) is preferably carried out by rotation of one, two, or more rotors.

[0053] A method as described above is preferred, in which step a) is as follows: a) Mixing a rubber mixture as described above or as described above for a mixing device described as preferred, in particular one which adheres at least partially to the side walls of the saddle or to the side walls of the ejection opening when ejected through the ejection opening of the mixing device. The mixing of the rubber mixture is preferably carried out by rotation of one, two, or additional rotors.

[0054] The advantageous aspects of a mixing device according to the invention described above also apply to all aspects of a method for cleaning a saddle of a mixing device described below, and the advantageous aspects of methods according to the invention for cleaning a saddle of a mixing device discussed below apply accordingly to all aspects of a mixing device according to the invention as described above or as described above as preferred or as particularly preferred or as very particularly preferred.

[0055] Further features, advantages and details, to which the invention is not limited in its scope, will now be described in more detail with reference to the drawings.

[0056] Fig. 1 shows a schematic representation of a mixing device 2. The mixing device 2 has a mixing chamber 9, a plunger 21, a chamber housing 1, a saddle 12 with hinge 13, two rotors 10, 11 and a shaft 22. The mixing chamber 9 is delimited by the chamber housing 1 by the ejection opening 8 and the filling opening 5. As shown in Fig. 1, the saddle 12 is in the closed state, which can be opened using the hinge until it rests against the corresponding side wall 24 of the shaft 22. Furthermore, the direction of rotation 23 of the rotors 10, 11 as well as two of the side walls 24, 25 of the shaft 22 are shown. Fig. The mixing device shown in Figure 1 could, for example, represent the upper mixing chamber of a tandem mixer. The front surface 15 of the saddle 12 has two concave areas, which merge into a convex rounding in the center of the front surface 15 of the saddle 12. The saddle 12 in Fig. 1 corresponds to a folding saddle. In Fig. 1 no removal devices are shown.

[0057] Fig. 2 shows a schematic representation of a mixing device 2 according to an embodiment of the present invention. Fig. The mixing device shown in Figure 2 could, for example, represent the upper mixing chamber of a tandem mixer. The mixing device 2 comprises a mixing chamber 9, a plunger 21, a chamber housing 1, a saddle 12 with a hinge 13, two rotors 10, 11, and a shaft 22. The mixing chamber 9 is delimited by the chamber housing 1 by the discharge opening 8 and the filling opening 5. Fig. The folding saddle shown in Figure 2 is in the open state, and the hinge side wall 7 of the ejection opening 8 forms an angle with the side wall 4 of the saddle 12, which angle converges towards the hinge. The space at this angle, also called the hinge angle, could be excellently removed of rubber mixture residues using a removal device described above, which has two planar outer surfaces, wherein the angle between the two planar outer surfaces approximately corresponds to the hinge angle. Such a removal device is preferably moved with the pointed edge of the two planar outer surfaces along the hinge axis when the saddle is in the open state, so that residues of the rubber mixture can be removed as efficiently as possible.

[0058] Schematically shown are several gas nozzles 14 as an example of several removal devices in the side walls 7, 6 of the ejection opening 8, in the side walls 3, 4 of the saddle 12, and in the end face 15 of the saddle 12. According to the invention, these are intended to remove residues of a rubber mixture from the corresponding surfaces.

[0059] Fig. 3 shows a schematic representation of a mixing device 2 according to the invention in a further embodiment of the present invention. Fig. The mixing device shown in Figure 3 could, for example, represent the upper mixing chamber of a tandem mixer. The mixing device 2 comprises a mixing chamber 9, a plunger 21, a chamber housing 1, a saddle 12 with a hinge 13, two rotors 10, 11, and a shaft 22. The mixing chamber 9 is delimited by the chamber housing 1 by the discharge opening 8 and the filling opening 5. As shown in Fig. 3, the saddle 12 is in the open position. Fig. The mixing device 2 shown in Figure 3 could be the upper or lower chamber of a tandem mixer.

[0060] Schematically, Fig. 3 shows several brushes 16 in the form of a brush roll. In addition, the respective direction of movement 17, 18 of the brush rolls is also shown, due to which at least a part of a rubber mixture adhering to the side walls of the saddle or to the side walls of the ejection opening 8 can be removed from the side walls of the saddle or the side walls of the ejection opening 8. The brushes 16 shown in the form of a brush roll are located in Fig. 3 in their initial or final position, which the brushes 16 assume before or after the removal described above. The brush rollers are rotated as required and moved in the direction of movement 17, 18 to ensure optimal removal of rubber compound residues.

[0061] Fig. 4 shows a schematic representation of the side view of a removal device which has an outer surface 19 on a concave side of the removal device 20, wherein all cross sections of the outer surface along a first direction 26, which goes into the plane of the paper, along the outer surface 19 represent a straight line and all cross sections of the outer surface 19 along the second direction 27 and perpendicular to the first direction 26 represent the circumferential profile of a cross section of the saddle 12, wherein the cross-sectional plane of the cross section of the saddle 12 for the circumferential profile runs perpendicular to the hinge axis of the hinge 13 and through the center point of the end face 15 of the saddle 12.In addition, a cross-section of a saddle 12 with an end face 15 is also shown for illustration to show that the cross-section of the outer surface 19 of the concave side of the removal device 20 corresponds to the circumferential profile of the side walls 3, 4 and the end face 15 of the saddle 12. The end face 15 of the saddle 12 has two concave regions 28 which merge into a convex rounded area 29 in the center of the end face 15 of the saddle 12. When the saddle 12 is in the open state, the removal device 20 described above is moved with the outer surface 19 along the saddle end face 15 so that residues of the rubber mixture can be removed as efficiently as possible. The same applies to a saddle shape as shown in . Fig. 1 to 3.

[0062] Fig.5 shows a schematic, three-dimensional representation of a removal device from a bird's eye view, which has an outer surface 19 on a concave side of the removal device 20, wherein all cross-sections of the outer surface along a first direction 26 and parallel to a second direction 27 perpendicular to the first direction represent a straight line and all cross-sections of the outer surface along the second direction 27 and perpendicular to the first direction 26 represent the circumferential profile of a cross-section of the saddle 12, wherein the cross-sectional plane of the cross-section of the saddle 12 for the circumferential profile runs perpendicular to the hinge axis of the hinge 13 and through the center of the saddle 12. List of reference symbols: 1 chamber housing 2 mixing device 3 Side wall of the folding saddle opposite the hinge 4 hinged side panel of the folding saddle 5 Filling opening 6 Side wall of the ejection opening opposite the hinge 7 Side wall of the ejection opening to which the hinge is attached 8 Ejection opening 9 Mixing chamber 10 Rotor 11 Rotor 12 Saddle 13 Hinge 14 Gas nozzle 15 Front surface of the saddle 16 brushes 17 Direction of movement of the brush on the hinge side 18 Direction of movement of the brush on the side walls opposite the hinge 19 Outer surface of the concave side 20 Removal device 21 stamps 22 Shaft 23 Direction of rotation of the rotors 24 Side wall of the shaft, which borders the hinge side wall of the ejection opening 25 Side wall of the shaft, which is opposite the hinge side wall of the ejection opening 26 first direction 27 second direction 28 concave areas of the saddle 29 convex rounding

Claims

[1] Mixing device (2) for mixing rubber mixtures, - with a mixing chamber (9) which is bounded by a chamber housing (1), a filling opening (5) and a discharge opening (8), and - with a saddle (12) designed to be adjustable for opening and closing the discharge opening (8), the side walls (3, 4) of which are in contact with the side walls (6, 7) of the discharge opening (8) when closed, characterized by , that - the mixing device (2) has one or more removal devices (14, 16, 20) which are designed to remove at least a part of a rubber mixture which adheres to the side walls (3, 4) of the saddle (12) or to the side walls (6, 7) of the discharge opening (8) from the side walls (3, 4) of the saddle (12) or the side walls (6, 7) of the discharge opening (8). [2] Mixing device (2) according to claim 1, characterized by, that the or at least one of the several removal devices (20) has one or more external surfaces (19) on a concave side of the one or at least one of the several removal devices (20), wherein - all cross-sections of one or at least one of the several outer surfaces (19) along a first direction (26) and parallel to a second direction (27) form a straight line and - all cross-sections of one or at least one of the several outer surfaces (19) along the second direction (27) and perpendicular to the first direction (26) represent the circumferential profile of a cross-section of the saddle (12), wherein the cross-sectional plane of the cross-section of the saddle (12) for the circumferential profile is perpendicular to the hinge axis of the hinge (13). [3] Mixing device (2) according to one of the preceding claims, characterized bythat one or more of the removal devices are one or more brushes (16). [4] Mixing device (2) according to claim 3, characterized by that one or at least one of the several removal devices is a brush (16), wherein the one brush (16) - is attached to an inner side wall (24, 25) of the shaft (22) at a predetermined distance from the discharge opening (8) and - is suitable for moving, when the saddle (12) is open, both over the side walls (3, 4) and the front surface (15) of the saddle (12) and over the hinge side wall (7) of the ejection opening (8), so that at least part of a rubber compound which adheres to the side walls (3, 4) of the saddle (12) or to the hinge side wall (7) of the ejection opening (8) is removed from the side walls (3, 4) of the saddle (12) or the hinge side wall (7) of the ejection opening (8). [5] Mixing device (2) according to claim 4, characterized by , that a second brush (16) is attached to the inner side wall (25) of the shaft (22) opposite the hinge (13) and is suitable for moving along the side wall (6) of the ejection opening (8) opposite the hinge (13) so that at least part of a rubber compound adhering to the side wall (6) of the ejection opening (8) opposite the hinge (13) is removed from the side wall (6) of the ejection opening (8). [6] Mixing device (2) according to any one of the preceding claims, characterized by , that the part of one or more removal devices (14, 16, 20) which comes into contact with a side wall (3, 4, 6, 7) of the saddle (12) or the ejection opening (8) when removing said part of a rubber compound, comprises or consists of a material selected from the group consisting of: - Metal, - Thermosets and - Thermoplastics. [7] Mixing device (2) according to any one of the preceding claims, characterized by , that one or more of the removal devices (14, 16, 20) are one or more gas nozzles (14) which are arranged in at least one side wall (3, 4) of the saddle (12) and / or in at least one side wall (6, 7) of the ejection opening (8), such that the gas coming from the nozzles (14) removes at least a part of a rubber mixture which adheres to the side walls (3, 4) of the saddle (12) or to the side walls (6, 7) of the ejection opening (8) from the side walls (3, 4) of the saddle (12) or the side walls (6, 7) of the ejection opening (8). [8] Mixing device (2) according to any one of the preceding claims, characterized by, that the saddle (12) is a folding saddle with a hinge (13) comprising two hinge bushings, wherein the hinge (13) is functionally attached by the first hinge bushing to a side wall (4) of the saddle (12) and by the second hinge bushing to a side wall (7) of the ejection opening (8). [9] Mixing device (2) according to any one of the preceding claims, characterized by , that the or at least one of the several removal devices (14, 16, 20) has two planar outer surfaces (19), wherein the angle between the two planar outer surfaces (19) corresponds approximately to the angle formed by the two hinge bushings of the hinge (13) of the folding saddle in the open state. [10] Method for cleaning a saddle (12) of a mixing device (2) as defined in claims 1 to 9, wherein the method comprises the following steps: a) Mixing a rubber mixture in a mixing chamber (9) of the mixing device (2), b) Ejection of the mixed rubber mixture through the ejection opening (8) of the mixing device (2) and c) Removing at least part of the portion of the mixed rubber compound adhering to the side walls (3, 4, 6, 7) of the saddle (12) or the side walls (6, 7) of the ejection opening (8) by means of one or more removal devices (14, 16, 20).

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