Device for producing a rubber compound

Abstract

Device for producing a rubber compound with at least one mixing chamber (1) and a chamber housing (2) which has a discharge opening (2'') bounded by edge surfaces (2a) and on which a saddle (7) for opening and closing the discharge opening (2'') is pivotably arranged, wherein the saddle (7) has edge surfaces (7a) inclined opposite to the edge surfaces (2a) of the chamber housing (2), wherein the edge surfaces (2a) of the chamber housing (2) and the edge surfaces (7a) of the saddle (7) are in contact with each other when the discharge opening (2'') is closed by the saddle (7), and wherein a shaft (6) bounded by shaft walls (6a) adjoins the discharge opening (2''), characterized in that discharge openings (8a, 9a) of nozzles are provided on the edge surfaces (2a) of the chamber housing (2) and / or the edge surfaces (7a) of the saddle (7) and / or on at least one of the shaft walls (6a). (8, 9) are provided for applying lubricant to the edge surfaces (2a, 7a).

Description

[0001] The invention relates to a device for producing a rubber compound with at least one mixing chamber having a chamber housing which has a discharge opening bounded by edge surfaces and on which a saddle for opening and closing the discharge opening is pivotably arranged, wherein the saddle has edge surfaces inclined opposite to the edge surfaces of the chamber housing, wherein the edge surfaces of the chamber housing and the edge surfaces of the saddle are in contact with each other when the discharge opening is closed by the saddle and wherein a shaft bounded by shaft walls adjoins the discharge opening.

[0002] It is known that rubber materials made from silica-filled rubber compounds are becoming increasingly important. These rubber materials are characterized by several advantageous properties. In particular, components of modern vehicle tires, such as treads, are made of such rubber materials.

[0003] For example, JP H06 - 32 010 U discloses a sealing device for an internal mixer which mixes, for example, rubber by rotating a rotor in a mixing chamber, in particular disclosing a method for adjusting the sealing pressure.

[0004] JP 2013 - 154 520 A relates, among other things, to a sealing mechanism and a sealing method for sealing a housing against a rotating agitator in a rubber stirring device for stirring raw rubber which is introduced into a mixing chamber inside the housing.

[0005] US 5,433,522 A relates to a closed kneader which has a hydraulic control device which includes a sealing surface pressure application circuit for applying a sealing surface pressure to a sealing device for rotors.

[0006] DE 10 2017 204 633 A1 relates to a mixing device for mixing rubber mixtures, with a mixing chamber which is bounded by a chamber housing, a filling opening and a discharge opening, and with a saddle adjustable for opening and closing the discharge opening, the side walls of which are in contact with the side walls of the discharge opening when closed.

[0007] Rubber compounds filled with silica are often very sticky, which makes the production of these rubber compounds in devices of the type mentioned above difficult.

[0008] With known devices for the production of rubber compounds, there is a risk that parts of the rubber compounds will stick to the edge surfaces that define the ejection opening of the chamber housing and to the edge surfaces of the saddle, thus preventing proper closure of the ejection opening by the saddle, which leads to malfunctions of the saddle locking mechanism and subsequent production failures.

[0009] The invention is based on the objective of reliably preventing the retention of rubber compound in the area of ​​the ejection opening of the chamber housing in a device of the type mentioned above.

[0010] The problem is solved according to the invention by providing nozzle outlets for applying lubricant to the surface areas on the outer surfaces of the chamber housing and / or the outer surfaces of the saddle and / or on at least one of the shaft walls.

[0011] The invention enables the particularly critical contact surfaces between the saddle and the chamber housing to be continuously or as needed sprayed with lubricant. This reliably prevents the rubber compound from adhering to the surface, ensuring proper closure of the ejection port and reliable locking of the saddle even after mixing a highly adhesive rubber compound. Since little to no rubber compound remains in the saddle area, successively produced rubber compounds retain their intended composition and are not contaminated.

[0012] Preferably, the lubricant is liquid, liquefied or powdered.

[0013] According to a preferred embodiment, the lubricant is a plasticizer used in rubber compounds. If such a lubricant enters the rubber compound in small quantities, no noticeable effects on the properties of the rubber compound or the rubber material produced from it are to be expected.

[0014] In another preferred embodiment, the plasticizer is a mineral oil plasticizer, preferably MES (mild extraction solvent), or an aromatic mineral oil, in particular RAE (residual aromatic extract) or TDAE (treated distillate aromatic extract). These plasticizers are frequently used in rubber compounds, and their compatibility with the rubber compound is therefore particularly good.

[0015] According to another preferred embodiment, the lubricant is a liquefied wax, for example liquefied paraffin or stearin. Such lubricants are also very compatible with rubber compounds.

[0016] In another preferred embodiment, the lubricant is a natural oil, for example rapeseed oil, palm oil or canola oil.

[0017] It is further preferred if the lubricant is powdered kaolin or powdered talc. Kaolin is frequently used as a filler in rubber compounds. Small amounts of talc are also well tolerated in rubber compounds.

[0018] Particularly preferably, the lubricant is a component of the rubber compound produced in the device.

[0019] Lubricant supply can be achieved in different ways. In one variant, the device has a reservoir for supplying the nozzles with lubricant. The design effort for this variant is very low.

[0020] Furthermore, variants are advantageous in which the nozzles are supplied with lubricant via a lubricant supply already present in the device. If the device has a lubricant supply for a jointed saddle assembly, the nozzles can be supplied with lubricant from this supply. If the device includes a pressurized piston with a lubricant supply, the nozzles can be supplied with lubricant from this supply. In a device with a lubricant supply for rotors located in the mixing chamber, the nozzles can be supplied with lubricant from this supply.

[0021] According to a further preferred embodiment, the device includes a temperature control device, in particular for heating the lubricant. Heating the lubricant reduces the viscosity of liquid lubricants, thus improving the lubricant's wetting properties and ensuring particularly thorough lubrication of the surface areas with minimal lubricant.

[0022] Further features, advantages, and details of the invention will now be described in more detail with reference to the drawing, which schematically illustrates exemplary embodiments of the invention. The drawing shows Fig. 1 a cross-section in the area of ​​a mixing chamber of an internal mixer with a first embodiment of the invention, Fig. 2 a further cross-section in the area of ​​the mixing chamber of the internal mixer with a first design variant and Fig. 3 a cross-section in the area of ​​a mixing chamber of an internal mixer with a second embodiment of the invention.

[0023] Fig. 1 and Fig. Figures 2 each show a mixing chamber 1 with a chamber housing 2 and two rotors 3 located inside the chamber housing 2. The direction of rotation of the rotors 3 is indicated by arrows P1. The chamber housing 2 has a substantially rectangular filling opening 2' above the rotors 3, into which a shaft 4, bounded by shaft walls 4a and of which a short end section is shown, opens. A pressurized piston 5, of which only a part is visible, is movable up and down in the shaft 4 in a known manner. The piston 5 is located in Fig. 1 to Fig. 3 in its lowered position, in which the piston 5 presses the mixture onto the rotors 3 during a mixing process and closes the filling opening 2' accordingly.

[0024] The chamber housing 2 has, below the rotors 3, a substantially rectangular discharge opening 2'' opposite the filling opening 2' ( Fig. 2) The ejection opening 2'' is defined by four conically inclined edge surfaces 2a ( Fig. 1) of the chamber housing 2, wherein, in the cross-sections shown, two of the boundary surfaces 2a are oriented towards the axis of rotation of the rotors 3. The two other boundary surfaces 2a, not shown, run perpendicular to the axis of rotation of the rotors 3. The boundary surfaces 2a are inclined to each other such that the width of the discharge opening 2'' decreases towards the interior of the mixing chamber 1.

[0025] Below the discharge opening 2', a shaft 6 adjoins the chamber housing 2, which is bounded by shaft walls 6a. Below the discharge opening, a saddle 7 is pivotally hinged to the chamber housing 2, which can be adjusted between an open position ( Fig. 1) and a closed position ( Fig. 2) is pivotable. In the open position, the saddle 7 is pivoted away from the discharge opening 2'', so that the material being mixed in the mixing chamber 1 is discharged. In the closed position, the saddle 7 closes the discharge opening 2".

[0026] The saddle 7 has four oppositely inclined edge surfaces 7a to the edge surfaces 2a of the ejection opening 2", such that the edge surfaces 7a of the saddle 7 in the closed position of the saddle 7 ( Fig. 2) Contact the edge surfaces 2a of the ejection opening 2" over a wide area.

[0027] At the in Fig. 1 and Fig. In the embodiment shown in Figure 2, a plurality of nozzles 8 are installed in the chamber housing 2, the outlet openings 8a of which are located on the edge surfaces 2a of the chamber housing 2. The supply lines to the nozzles 8, which are only indicated, run from the edge surfaces 2a of the chamber housing 2 to the outside of the chamber housing 2. Lubricant is supplied via these supply lines in a manner not shown.

[0028] The nozzles 8 allow the outer surfaces 2a of the chamber housing 2, and, in the closed position of the saddle 7, the outer surfaces 7a of the saddle 7, to be wetted and lubricated with the lubricant. The lubrication of the contacting outer surfaces 2a and 7a can be carried out continuously or discontinuously by means of individual spray bursts. Each spray burst applies a few grams of lubricant to the outer surfaces 2a and 7a. The nozzles 8 and 9 can be actuated by the control unit of the respective mixing device or by a separate control unit.

[0029] Suitable lubricants include, for example, a plasticizer, a natural oil, powdered kaolin, powdered talc, or liquid stearic acid. The plasticizer is preferably a liquefied wax, a mineral oil plasticizer (preferably MES, mild extraction solvent), or an aromatic mineral oil, particularly RAE (residual aromatic extract) or TDAE (treated distillate aromatic extract). Rapeseed oil, palm oil, or canola oil are preferably used as natural oils. If a liquid lubricant is used, it is preferred to heat the lubricant before supplying it to the nozzles 8 using a device not shown, so that the viscosity of the lubricant is reduced and the surface areas 2a and 7a are particularly well wetted. The lubricant originates, for example, from a reservoir (not shown) from which it is pumped to the nozzles 8.

[0030] The lubricant supply to the nozzles 8 can alternatively be provided via an existing lubricant supply, for example the lubricant supply of the swiveling saddle 7, the lubricant supply of the piston 5 or the lubricant supply of the rotors 3.

[0031] The in Fig. The third version shown differs from the version shown in Fig. 1 and Fig. 2 by installing the nozzles 9 together with their supply lines in at least one shaft wall 6a. The outlet openings 9a of the nozzles 9 are located on the inside of the shaft wall 6a. Nozzles 9 are preferably installed in all shaft walls 6a.

[0032] According to another embodiment not shown, nozzles are installed in the saddle 7 in an analogous manner. Their outlet openings are located on the edge surfaces 7a of the saddle 7.

[0033] The invention is not limited to the described embodiments. In particular, the described measures are also suitable for lubrication in the area of ​​saddles of tandem mixers. Reference symbol list 1 mixing chamber 2-chamber housing 2' Filling opening 2'' ejection opening 2a Edge areas 3 Rotor 4 shaft 4a Shaft wall 5 stamps 6 Shaft 6a Shaft wall 7 saddles 7a Edge areas 8 nozzles 8a Exit openings 9 nozzles 9a Exit openings P1 Arrow (direction of rotation)

Claims

[1] Device for producing a rubber compound with at least one mixing chamber (1) with a chamber housing (2) which has a discharge opening (2'') bounded by edge surfaces (2a) and on which a saddle (7) for opening and closing the discharge opening (2'') is pivotably arranged, wherein the saddle (7) has edge surfaces (7a) inclined opposite to the edge surfaces (2a) of the chamber housing (2), wherein the edge surfaces (2a) of the chamber housing (2) and the edge surfaces (7a) of the saddle (7) are in contact with each other when the discharge opening () is closed by the saddle (7) and wherein a shaft (6) bounded by shaft walls (6a) adjoins the discharge opening (2''), characterized by , that outlet openings (8a, 9a) of nozzles (8, 9) for applying lubricant to the edge surfaces (2a, 7a) are provided on the outer surfaces (2a) of the chamber housing (2) and / or on the outer surfaces (7a) of the saddle (7) and / or on at least one of the shaft walls (6a). [2] Device according to claim 1, characterized by that the lubricant is liquid, liquefied, or powdered. [3] Device according to claim 1 or 2, characterized by that the lubricant is a plasticizer used in rubber compounds. [4] Device according to claim 3, characterized by that the lubricant is a mineral oil plasticizer, preferably MES (mild extraction solvate) or an aromatic mineral oil, in particular RAE (residual aromatic extract) or TDAE (treated distillate aromatic extract). [5] Device according to claim 1 or 2, characterized by that the lubricant is a liquefied wax, for example liquefied paraffin or stearin. [6] Device according to claim 1 or 2, characterized by that the lubricant is a natural oil, for example rapeseed oil, palm oil or canola oil. [7] Device according to claim 1 or 2, characterized bythat the lubricant is powdered kaolin or powdered talc. [8] Device according to any one of claims 1 to 7, characterized by that the lubricant is a component of the rubber compound produced in the device. [9] Device according to any one of claims 1 to 8, characterized by , that it has a reservoir for supplying the nozzles (8, 9) with lubricant. [10] Device according to one of claims 1 to 9 with a lubricant supply for a joint arrangement of the saddle (7), characterized by , that the nozzles (8, 9) can be supplied with lubricant from this lubricant supply. [11] Device according to one of claims 1 to 9 comprising a pressurized piston (5) with a lubricant supply, characterized by , that the nozzles (8, 9) can be supplied with lubricant from this lubricant supply. [12] Device according to one of claims 1 to 9 with a lubricant supply to rotors (3) located in the mixing chamber (1), characterized by , that the nozzles (8, 9) can be supplied with lubricant from this lubricant supply. [13] Device according to any one of claims 1 to 12, characterized by that it has a device for temperature control, in particular for heating the lubricant.

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