Abstract
An internal mixer includes a mixing chamber enclosed by a housing, a feeding neck in which a ram is guided, a closable discharge door, and an intermeshing rotor system, composed of a pair of rotors that can each be rotated about a rotor longitudinal axis, each rotor comprising a rotor main body on which at least one respective rotor blade is arranged, and the rotor blades of the two rotors meshing with one another, is to be refined in such a way that an improved, that is, faster, pull-in behavior is achieved, while optimizing the dispersion and distribution of the introduced materials. To this end, it is provided that in the case of at least one of the rotors, the rotor main body, at least in sub-regions, is non-cylindrical and has a non-circular cross-section, in the surface sections in which no rotor blades are arranged on the rotor main body.
Claims
1. An internal mixer, comprising: a mixing chamber enclosed by a housing; a feeding neck in which a ram is guided; a closable discharge door; and an intermeshing rotor system, composed of a pair of rotors that can each be rotated about a rotor longitudinal axis, each rotor comprising a rotor main body on which at least one respective rotor blade is arranged, and the rotor blades of the pair of rotors meshing with one another, wherein in the case of at least one of the rotors, the rotor main body, at least in sub-regions, is non-cylindrical and has a non-circular cross-section, in the surface sections in which no rotor blades are arranged on the rotor main body), and which are located in the interaction region with the rotor blade tips of the second rotor, non-cylindrical and non-circular denoting an arbitrary envelope of the rotor main body in the interaction surface sections in which recesses are deliberately introduced in certain locations into the surface of the rotor main bodies or elevations applied onto the surface of the rotor main bodies.
2. The internal mixer according to claim 1, wherein in the interaction sub-regions of the rotor main body, the distance between the rotor main body surface and the rotor longitudinal axis is different between at least two planes that are situated perpendicularly to the rotor longitudinal axis and the axial positions of which can be predefined, at least along a rotor main body circumferential segment.
3. The internal mixer according to claim 2, wherein the differing distance can be provided in the radial and/or axial directions.
4. The internal mixer according to claim 2, wherein the distances change steadily.
5. The internal mixer according to claim 1, wherein the clearance between one of the rotor main bodies and the rotor blade tips the second rotor main body decreases in the direction of the rotor longitudinal axes toward the rotor ends.
6. The internal mixer according to claim 1, wherein the clearance between one of the rotor main bodies and the rotor blade tips of the second rotor main body increases in the direction of the rotor longitudinal axes toward the rotor ends.
7. The internal mixer according to claim 1, wherein the at least one rotor comprises a centrally arranged, long rotor blade that extends along at least half the rotor length and is helically arranged on the rotor main body, as well as likewise helically designed, shorter rotor blades arranged in the respective end regions of the rotor, the pitch of one of the rotor blades being in the opposite direction in relation to the pitch of the two other rotor blades, and in that passages for material to be mixed are provided between the free ends of the rotor blades.
8. The internal mixer according to claim 1, wherein the sub-region extends along the entire rotor main body on which no rotor blades are arranged.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The invention will be described in more detail based on drawings.
[0022] FIG. 1 shows a representative illustration of an internal mixer according to the invention.
[0023] FIG. 2 shows a schematic side view of a rotor comprising rotor blades.
[0024] FIG. 3 shows a sectional view through a rotor main body without rotor blades.
[0025] FIG. 4 shows two rotors according to the invention.
[0026] FIG. 5 shows a detail between the two rotors according to the invention.
[0027] FIG. 6A shows two perspectively illustrated rotors according to the invention.
[0028] FIG. 6B shows a detail from FIG. 6A.
[0029] FIGS. 7A-7D show four snapshots of two rotors during an approximately 30° rotation, seen from FIG. 6A in the direction of arrows D-D.
[0030] FIG. 8 shows the developed view of a rotor main body of a first rotor, including the roll areas or the rotor blade tips of a second rotor.
[0031] FIGS. 9A-9D show four examples of a variation of the clearance contours.
DETAILED DESCRIPTION
[0032] FIG. 1 shows an internal mixer 1 according to the invention, comprising a housing 2 that encloses a mixing chamber 3, and a feeding neck 4 including a ram 5 by way of which the mixing chamber 3 can be closed toward the top. Furthermore, a closable discharge door 6 is apparent, which is able to close the mixing chamber 3 toward the bottom, wherein the finished mixed product can be discharged from the mixing chamber 3 when the discharge door 6 is open.
[0033] Moreover, two rotors 7 and 8, including the rotor main bodies 9 and 10 thereof and the rotor blades 11 and 12, are apparent. The rotor longitudinal axes 13 and 14 of the rotors 7 and 8 are located so closely together that the rotors 7 and 8 intermesh with the blades 11 and 12 thereof.
[0034] FIG. 2 shows a rotor 7, (8) comprising the rotor main body 9, (10) and the rotor blades 11, (12), which end in the rotor blade tips 17, (18). The rotor longitudinal axis 13, (14) is likewise hinted at. The hinted-at two radii R1 and R2, the centers of which are arranged offset from the rotor longitudinal axis 13, (14) by the magnitudes YR1-XR1 and YR2-XR2, shows that the rotor 7, (8) does not comprise a circular cylindrical main body, as is the case with rotors known to date, but that the rotor main body 9, (10) can have an arbitrary envelope, wherein the radius is smaller, for example, in the locations in which no rotor blades 11, (12) are provided than in the remaining regions of the rotor main body 9, (10) so as to improve the pull-in behavior.
[0035] FIG. 3 shows, as a further example, the cross-section through a rotor main body 9, (10), wherein the rotor longitudinal axis 13, (14) and centers deviating therefrom are apparent for different radii Re1 to Re4. In the end regions of the rotor main bodies 9, (10), elevations have been applied to the rotor main body 9, (10) here, as a result of which the rotor main body loses the circularly hinted-at form thereof, and whereby the clearances between the rotor main body 9, (10) of the first rotor 7, (8) and the rotor blade tips of the second rotor 8, (7) become even narrower in the edge region, so that particularly good dispersion work can be achieved in this region.
[0036] FIG. 4 shows a perspective illustration of the rotors 7 and 8, including the rotor main bodies 9 and 10 thereof and rotor blades 11, 11′, 11″ and 12, 12′, 12″. It is apparent here that the clearance between the rotor main body 10 and the rotor blade tip 17″ in the axial direction and in the direction of rotation is larger in a center region 15 than in the edge region 16. As a result of the clearance increasing from the edge region 16 to the center region 15, it is achieved that the material to be mixed, after having been pulled from the feeding neck 4 and distributed in the mixing chamber 3, can flow in the direction toward the center region 15, where more space is available for the material. This improves the distribution of the material. In contrast, particularly good dispersion work is achieved in the small clearance in the edge region 16.
[0037] This not only improves the pull-in, but also optimizes the dispersion and distribution of the materials.
[0038] FIG. 5 shows a detail of FIG. 4. The rotation main bodies 9 and 10 are apparent here. At the same time, it is apparent that the clearance is considerably smaller in the edge region 16 than toward the rotor center 15. Furthermore, one of the dust seals 21 at the end of the rotor is shown.
[0039] FIG. 6A, similarly to FIG. 4, shows a perspective illustration of two rotors 7, 8 of a rotor pair. In addition to rotor blades 11, 11′, 11″; 12, 12′, 12″, elevations 19, 20 according to the invention are shown both on the rotor main body 9 of the rotor 7 and on the rotor main body 10 of the rotor 8, the rotor main bodies 9, 10 not being cylindrical and having non-circular cross-sections in the region of the elevations.
[0040] In a detail, FIG. 6B shows the region in which the rotor blade 12 meets with the elevation 19, wherein it is apparent that the radial distance of the rotor blade tip 18 decreases toward the elevation 19 in the direction of rotation of the rotors.
[0041] FIG. 7 shows four snapshots of two rotors according to the invention during an approximately 30° rotation of the rotors. The changes in the clearance during a quasi rolling process between the blade tip 18 of the rotor 8 toward the rotor main body 9 of the rotor 7 are apparent. FIG. 7A shows a large clearance Ca at the start at 0°. The clearance C after 8° according to FIG. 7B is already smaller, and decreases over FIG. 7c at 20°, until the clearance at the end of Ce at 30° according to FIG. 7D is almost no longer apparent.
[0042] FIG. 8, by way of example, shows the development of a rotor 7, (8), wherein rotor blades 11, (12); 11′, (12′); 11″, (12″) are apparent on the rotor main body 9, (10). The interaction region of the rotor blade tips 18, (17); 18′, (17′); 18″ (17″), which roll on the rotor main body 9, (10) during a revolution between the rotor blades 11, (12); 11′, (12′); 11″, (12″), are shown hatched. The shown length B corresponds to the radian of the rotor blade tips 18, (17); 18′, (17′); 18″ (17″).
[0043] FIG. 9 shows four examples as to how the clearance contour changes with different changes of the recesses/elevations that result according to the invention.
[0044] FIG. 9A shows the clearance contour with a linearly decreasing recess. Ca represents the clearance width at the start of the interaction between the rotor blade tip of the one rotor and the rotor main body of the other rotor. Ce represents the clearance width at the end of the interaction, while B shows the radian of the blade tip, which corresponds to the interaction length perpendicularly to the rotor longitudinal axis.
[0045] In FIG. 9B, the depth of the recess changes in a non-linear manner. Two different examples for this non-linearity are indicated.
[0046] FIG. 9C shows the recess again in a linear manner, or shows a linear elevation at the rotor main body.
[0047] FIG. 9D, in contrast, shows two examples of a non-linear elevation of the rotor main body.
[0048] While the invention has been described with reference to exemplary embodiments and applications scenarios, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the claims. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims and can be applied to various application in the industrial as well as commercial field.
