Device for producing a rubber compound

Abstract

Device for producing a rubber compound with at least one mixing chamber, a shaft (1) opening into the mixing chamber with a shaft wall (1a) in which a feeding opening (3) is formed, wherein a loading flap (2) is pivotably arranged on the shaft wall (1a) for opening and closing the feeding opening (3), which in the closed state extends substantially in the extension of the inside (1b) of the shaft wall (1a), characterized in that the loading flap (2) is pivotably arranged on the shaft wall (1a) by means of an elastically flexible sheet (5) which is attached to the loading flap (2) and to the shaft wall (1a) and bridges a gap-like space (6) formed between the lower edge of the loading flap (2) and the lower edge of the feeding opening (3).

Description

[0001] The invention relates to a device for producing a rubber mixture with at least one mixing chamber, a shaft opening into the mixing chamber with a shaft wall in which a feeding opening is formed, wherein a loading flap is pivotably arranged on the shaft wall for opening and closing the feeding opening, which loading flap in the closed state runs essentially in extension of the inside of the shaft wall.

[0002] It is known and common practice to produce rubber compounds in devices of the type mentioned above. Such a device is known, for example, from DE 10 2014 202 467 A1.

[0003] DE 10 2018 208 711 A1 relates to a feed chute for stamp kneaders in which a stamp is guided, wherein a filling opening is provided in at least one wall of the feed chute, which filling opening can be closed by means of a filling flap mounted on the feed chute on a pivot axis, which flap can be pivoted about the pivot axis by means of a drive between an open position and a closed position, and provides a sealing element for sealing the pivot axis with respect to the feed chute.

[0004] DE 11 78 830 A relates to a kneader with a feeding chamber for material to be processed, in particular consisting of rubber or the like and fillers, and to be pressed against the kneading tools, wherein the feeding chamber is provided with a feeding flap guided between boundary walls formed by side extensions of the feeding chamber.

[0005] CN 2 04 398 181 U relates to a spindle sealing device for Banbury doors, which is characterized in that the sealing device comprises a sealing receptacle, the sealing receptacle is attached to gallery openings and a reinforced door hinge and the gallery openings are attached to a reinforced door.

[0006] CN 1 02 922 615 A ​​relates in particular to a type of hermetically sealed construction of gallery connections of the Banbury loading system.

[0007] CN 1 01 434 109 A relates in particular to a mixer loading door shaft auxiliary sealing device arranged on a lower part of a front wall of a loading hopper.

[0008] During the production of a rubber compound, components of the rubber compound, especially rubbers, are fed into the shaft leading to the mixing chamber via the feed opening formed on the shaft. Powdered components of the compound, especially fillers such as carbon black or silica, can also be fed into the loading shaft via the feed opening or via a side pipe.

[0009] The loading flap for closing and opening the feed opening is usually connected to the shaft wall via a swivel joint at its lower edge. Due to the design, a narrow gap exists between the loading flap and the shaft wall in the area of ​​the swivel joint. To seal the device in the area of ​​this gap, the swivel joint is provided with one or more sealing strips on its outer circumference or edge. These sealing strips and the swivel joint are also coated with sealing grease to ensure adequate sealing.

[0010] During a mixing process, a mixer ram, which can be moved up and down within the shaft, moves down the shaft, pressing the mixture components into the rotors located there. During this process, it can undesirably occur that powdered mixture components escape from the mixing chamber through gaps between the mixer ram and the shaft wall and are transported up through the shaft to the top of the mixer ram.

[0011] It has been found that, despite the sealing strips provided, particulate mixture components, particularly filler particles, transported to the top of the mixer ram contaminate the swivel joint connecting the loading flap to the shaft wall. The particles adhere to the sealing grease located there, which can adversely affect the quality of the rubber compounds being produced. Furthermore, small amounts of the sealing grease often find their way down into the mixing chamber, thereby contaminating the rubber compound itself.

[0012] The invention is therefore based on the object of being able to reliably seal the loading flap to the shaft in a device of the type mentioned at the beginning and to prevent contamination by sealing grease.

[0013] The stated object is achieved according to the invention in that the loading flap is pivotably arranged on the shaft wall by means of an elastically flexible sheet metal which is fastened to the loading flap and to the shaft wall and bridges a gap-like space formed between the lower edge of the loading flap and the lower edge of the feeding opening.

[0014] According to the invention, the loading flap is pivotally connected to the shaft wall by means of an elastically flexible sheet metal member. Such a sheet metal member can be easily and durably attached to the loading flap and the shaft wall. In contrast to the known complex swivel joint located at the transition from the loading flap to the shaft, the space between the lower end of the loading flap and the shaft wall is completely covered and reliably sealed, preventing any mixture components from adhering in this area. The use of sealing grease is unnecessary. Any powdered mixture components transported upwards during the mixing process slide over the smooth sheet metal member and through the gap between the mixer ram and the shaft wall back into the mixing chamber, where they are mixed into the rubber mixture.

[0015] It is particularly simple and practical to attach the sheet metal to the top of the loading hatch and to the inside of the shaft wall, preferably using screws and / or rivets.

[0016] According to a preferred embodiment, the sheet metal is made of spring steel, a material that is particularly wear-resistant.

[0017] For the bending behavior of the sheet, it is advantageous if the spring steel of the sheet has an elastic limit of at least 1150 N / mm 2 with a tensile strength of 1300 N / mm 2 up to 1600 N / mm 2 has.

[0018] According to further preferred embodiments, the sheet consists of a silicon-chromium steel, a silicon-chromium-vanadium steel or a chromium-vanadium steel.

[0019] For the bending behavior and durability of the sheet, it is advantageous if the sheet has a thickness of 3.0 mm to 6.0 mm, especially 5.0 mm.

[0020] In a preferred embodiment, it is further provided that the sheet is fastened to the loading hatch in a shallow recess formed in the loading hatch, the depth of which essentially corresponds to the thickness of the sheet. It is also preferably provided that the sheet is fastened to the shaft wall in a shallow recess thereof, the depth of which essentially corresponds to the thickness of the sheet. These measures ensure that no mixture components can become stuck in the area of ​​the loading shaft during their addition. Likewise, any particulate mixture components transported upwards during the mixing process are transported downwards in a particularly reliable manner, as they simply slide down the smooth bending sheet. Furthermore, any mixer ram that can be moved up and down in the shaft can move unhindered.

[0021] The device according to the invention is in particular an internal mixer or an upper machine of a tandem mixer.

[0022] Further features, advantages and details of the invention will now be explained with reference to the single figure, Fig. 1, which shows a schematic cross section through a portion of an apparatus for producing a rubber mixture, is described in more detail.

[0023] Devices for producing rubber mixtures comprise, in particular, at least one mixing chamber with rotors and a discharge flap, a vertically extending shaft, the lower end of which opens into the mixing chamber, and a pressurized mixer ram that can be moved up and down vertically within the shaft. The mixer ram can be used to force mixture components, such as rubbers and fillers, into the rotors arranged in the mixing chamber during the mixing process.

[0024] Fig. 1 shows a section of a shaft 1 and a pivotable loading flap 2 arranged laterally on the shaft 1, via which in particular an internal mixer or an upper machine of a tandem mixer is fed with mixing components. The shaft 1 has a shaft wall 1a with an inner side 1b bordering the shaft wall 1a. A feeding opening 3 is formed on the shaft wall 1a, which can be closed and opened by means of the loading flap 2. Accordingly, the feeding opening 3 and the loading flap 2 have dimensions adapted to one another, in particular the opening perpendicular to the Fig. The width of the loading flap 2 shown in the sectional view in Figure 1 is adapted to the width of the feeding opening 3 and corresponds to this.

[0025] In Fig. 1, the loading flap 2 is pivoted such that the feed opening 3 is open, wherein the loading flap 2 in this position has an opening angle α of 30° to 45°, in particular of up to 40°, relative to the vertical direction. In the open state of the loading flap 2, mixture components of rubber mixtures can be fed into the shaft 1 via this and the feed opening 3. The position in which the loading flap 2 closes the feed opening 3 is shown in Fig. 1 is indicated by dash-dotted lines. The loading flap 2 has an upper side 2a, which, when the loading flap 2 is closed, is at least substantially flush with the inner side.

[0026] The loading flap 2 is actuated via a drive 4, to which the loading flap 2 is preferably coupled in a known manner. The drive 4 is, for example, a pneumatic or motor drive with at least one hydraulic cylinder.

[0027] A gap-like space 6 remains between the lower edge of the loading flap 2 and the lower edge of the feeding opening 3 on the shaft wall 1a, which is bridged by an elastically flexible sheet 5 extending across the width of the loading flap 2 and thus also across the width of the feeding opening 3. The sheet 5 is fastened to the upper side 2a of the loading flap 2 at the lower edge thereof and to the edge section of the inside of the shaft wall 1a at the lower end of the feeding opening 3. In the embodiment shown, screws 7 are provided as fastening elements. Alternatively, rivets or the like can be used as fastening elements.

[0028] The attached sections of the sheet 5 are preferably located in shallow recesses in the loading flap 2 or the shaft wall 1a, wherein the depth of the recesses corresponds in particular to the thickness of the sheet 5. Therefore, the sheet 5 preferably does not protrude beyond the upper side 2a of the loading flap 2 and the inside of the shaft wall 1a, but is essentially flush with them.

[0029] This measure ensures unhindered up and down movement of the mixer ram in shaft 1.

[0030] The sheet 5 has a thickness of 3.0 mm to 6.0 mm, in particular 5.0 mm, and consists of a spring steel, in particular a silicon-chromium steel, a silicon-chromium-vanadium steel, or a chromium-vanadium steel. The spring steel has an elastic limit of at least 1150 N / mm 2 with a tensile strength of 1300 N / mm 2 up to 1600 N / mm 2The elastic limit indicates the stress up to which the sheet 5 can be elastically deformed. List of reference numbers 1 shaft 1a Shaft wall 1b Inside 2 loading flap 2a top 3 Feeding opening 4 Drive 5 sheet metal 6 gap 7 screw

Claims

[1] Device for producing a rubber mixture with at least one mixing chamber, a shaft (1) opening into the mixing chamber with a shaft wall (1a) in which a feeding opening (3) is formed, wherein a loading flap (2) is pivotably arranged on the shaft wall (1a) for opening and closing the feeding opening (3), which in the closed state runs essentially in extension of the inner side (1b) of the shaft wall (1a), characterized by that the loading flap (2) is pivotably arranged on the shaft wall (1a) by means of an elastically flexible sheet metal member (5) which is fastened to the loading flap (2) and to the shaft wall (1a) and bridges a gap-like intermediate space (6) formed between the lower edge of the loading flap (2) and the lower edge of the feeding opening (3). [2] Device according to claim 1, characterized bythat the sheet (5) is attached to the top side (2a) of the loading flap (2) and to the inside of the shaft wall (1a). [3] Device according to claim 2, characterized by that the sheet (5) is fastened by means of screws (7) and / or rivets. [4] Device according to one of claims 1 to 3, characterized by that the sheet (5) is made of spring steel. [5] Device according to claim 4, characterized by that the spring steel of the sheet (5) has an elastic limit of at least 1150 N / mm 2 with a tensile strength of 1300 N / mm 2 up to 1600 N / mm 2 has. [6] Device according to one of claims 1 to 5, characterized by that the sheet (5) consists of a silicon-chromium steel. [7] Device according to one of claims 1 to 5, characterized by that the sheet (5) consists of a silicon-chromium-vanadium steel. [8] Device according to one of claims 1 to 5, characterized bythat the sheet (5) is made of a chrome-vanadium steel. [9] Device according to one of claims 1 to 8, characterized by that the sheet (5) has a thickness of 3.0 mm to 6.0 mm, in particular 5.0 mm. [10] Device according to one of claims 1 to 9, characterized by that the sheet (5) is fastened to the loading flap (2) in a shallow recess formed in the loading flap (2), the depth of which substantially corresponds to the thickness of the sheet (5). [11] Device according to one of claims 1 to 9, characterized by that the sheet (5) is fastened to the shaft wall (1a) in a shallow recess formed in the shaft wall (1a), the depth of which substantially corresponds to the thickness of the sheet (5). [12] Device according to one of claims 1 to 11, which is an internal mixer. [13] Device according to one of claims 1 to 11, which is an upper machine of a tandem mixer.

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