Apparatus for mixing a powdered material with a liquid

Abstract

Apparatus for mixing a powdered material with a liquid that includes a housing in which a working space having an inner wall is arranged and a rotatably-driven rotor being arranged in the working space. The rotatably-driven rotor includes a blade ring and bars, which are pointing toward the inner wall and are arranged at different positions in a circumferential direction of the rotor. The apparatus also includes a feed opening for the powdered material being arranged above the blade ring and an annular gap connectable to a liquid supply arrangement being arranged below the blade ring. In a direction parallel to an axial direction of the rotor, the bars one of connect to one another or overlap one another.

Claims

1. An apparatus for mixing a powdered material with a liquid, comprising: a housing in which a working space having an inner wall is arranged; a rotatably-driven rotor being arranged in the working space, the rotatably-driven rotor comprising a blade ring and bars, which are pointing toward the inner wall and are arranged at different positions in a circumferential direction of the rotor and at different positions along an axial direction of the rotor; a feed opening for the powdered material being arranged above the blade ring; and an annular gap connectable to a liquid supply arrangement being arranged below the blade ring, wherein adjacent bars in the axial direction of the rotor one of connect to one another or overlap one another in the axial direction, so that, in rotation, axial extents of the adjacent bars overlap each other in the axial direction.

2. The apparatus according to claim 1, wherein bars adjacent in the axial direction of the rotor are separated by angular distances in the circumferential direction, and wherein the angular distances include a first angular distance that differs from an adjacent, second angular distance.

3. The apparatus according to claim 2, wherein the first angular distance is positive and the second angular distance is negative.

4. The apparatus according to claim 1, wherein the bars are arranged solely on a side of the blade ring facing away from the feed opening.

5. The apparatus according to claim 4, wherein, with respect to the axial direction of the rotor, the bars are arranged on both above and below the annular gap.

6. The apparatus according to claim 1, wherein small distances are embodied between radial outer ends of the bars and the inner wall.

7. The apparatus according to claim 1, wherein the blade ring comprises radially extending blades oriented, at least at their radial outsides, at an angle to the circumferential direction in a range of 2 to 8.

8. The apparatus according to claim 7, wherein the blades comprise a twist about a blade axis extending from a radial inside to a radial outside.

9. The apparatus according to claim 1, wherein at least one of the housing and the rotor comprise a heating device.

10. A apparatus for mixing a powdered material with a liquid, comprising: a housing in which a working space having an inner wall is arranged; a rotatably-driven rotor being arranged in the working space, the rotatably-driven rotor comprising a blade ring and bars, which are pointing toward the inner wall and are arranged at different positions in a circumferential direction of the rotor; a feed opening for the powdered material being arranged above the blade ring; and an annular gap connectable to a liquid supply arrangement being arranged below the blade ring, wherein, in a direction parallel to an axial direction of the rotor, the bars one of connect to one another or overlap one another, wherein the housing further comprises: an outlet at a bottom end of the working space, wherein a bottom edge of a bar adjacent to the outlet is flush with the bottom edge of the working space, and an outlet section connected to the outlet.

11. The apparatus according to claim 10, wherein the outlet section comprises a radial recess in an outward direction across from the outlet.

12. The apparatus according to claim 11, wherein the radial recess corresponds at least to a thickness of a wall of the housing surrounding the working space.

13. The apparatus according to claim 10, wherein the outlet section is formed from an elastic material.

14. The apparatus according to claim 10, wherein the outlet section widens away from the outlet.

15. The apparatus according to claim 10, wherein the outlet section comprises a non-stick surface.

16. A method for mixing a powdered material with a liquid, comprising: supplying the powdered material into a working space having an inner wall; distributing the powdered material onto the inner wall via a blade ring arranged within the working space; wetting the powdered material below the blade ring with the liquid; and intermixing the powdered material with the liquid via bars radially extending toward the inner wall from a rotor arranged within the working space, wherein the radially extending bars are axially positioned along the rotor and circumferentially positioned around the rotor so that, adjacent bars in the axial direction of the rotor one of connect to one another or overlap one another in the axial direction, and so that, in rotation, axial extents of the adjacent bars overlap each other in the axial direction, whereby for the axial extent of the radially extending bars, there is virtually no region in the axial direction in which the powdered material is not impinged by the bars.

17. The method according to claim 16, further comprising: scraping the intermixed powered material and liquid off the inner wall with a bottommost bar arranged adjacent an outlet formed in a bottom of the working space.

18. The method according to claim 17, further comprising: guiding the scraped intermixed powered material and liquid to the outlet.

19. The method according to claim 16, wherein the wetting comprises distributing the liquid to the powdered material via impingement with the bars.

20. The method according to claim 16, wherein the bars do not contact the inner wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:

(2) FIG. 1 shows a vertical longitudinal section through an apparatus for mixing a powdered material with a liquid;

(3) FIG. 2 shows an enlarged detailed view C from FIG. 1; and

(4) FIG. 3 shows a section BB according to FIG. 1.

DETAILED DESCRIPTION

(5) The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice.

(6) An apparatus 1 for mixing a powdered material with a liquid comprises a housing 2 in which a working space 3 is arranged. The working space 3 comprises an inner wall 4. The inner wall 4 is at the same time the inside wall of the housing 2.

(7) The working space 3 is embodied as a hollow cylinder with a circular cross section. In the working space 3, a rotatably-driven rotor 5 is arranged. The rotor 5 is driven by a motor 6 that is arranged above the housing 2.

(8) The rotor 5 comprises a blade ring 7. The blade ring 7 comprises a plurality of blades 8 distributed in a circumferential direction (FIG. 3). The blades 8 have, at least at their radial outside, an angle to the circumferential direction in the range of 2 to 8. This inclination is achieved in that the blades 8 comprise a twist about an axis extending from the radial inside to the radial outside. On the radial inside, the blades 8 can be aligned parallel to the circumferential direction. Since the inclination angle is very small, it cannot be seen in the drawing. Gaps 9 are provided between the blades 8.

(9) If the blades 8 are inclined relative to the circumferential direction at their radial outside, this inclination is selected such that, during a rotation of the rotor 5 about the rotor axis 10 thereof, a small airflow results in the direction from a feed opening 11, into which the powdered material can be introduced, to an outlet 12, at which the powdered material mixed with the liquid exits the housing 2. The rotational axis is aligned vertically, that is, parallel to the direction of gravity. Certain deviations from the direction of gravity are possible, as long as the gravitational force is sufficient to convey the powdered material, and subsequently the powdered material mixed with the liquid, from the feed opening 11 to the outlet 12.

(10) On the side of the blade ring 7 facing away from the feed opening 11, the rotor 5 comprises an annular gap 13 which is connected to a liquid supply device 14 via a channel 15.

(11) Furthermore, on the side of the blade ring 7 facing away from the feed opening 11, the rotor 5 comprises bars 16 that are arranged at different positions in a circumferential direction of the rotor 5. As can be seen in FIGS. 1 and 2, the bars 16 slightly overlap in an axial direction of the rotor 5. However, it would also be sufficient if the bars 16 were to connect to one another in an axial direction of the rotor. The effect of this arrangement is that, in the region of the bars 16, the inner wall 4 is scraped over once by a bar 16 at every axial position during a revolution of the rotor 5. As explained further below, a residual ring of the powdered material supplied through the feed opening 11 thus cannot be produced. At all positions, the powdered material, which is spun radially outwards against the inner wall 4 on impact with the blades 8 of the blade ring 7, is scraped off of the inner wall 4, or at least impinged upon, by the bars 16.

(12) The bars 16 are arranged on both sides of the annular gap 13 in an axial direction. The number of bars 16 on each side of the annular gap 13 can essentially be selected at will. If liquid exits the annular gap 13 and is conveyed radially outwards by the centrifugal force, then this liquid also impacts bars 16. On impact with these bars 16, a change in direction then takes place which allows the liquid to reach a region on the inner wall 4 of the working space 3 above the annular gap 13, even against the direction of gravity.

(13) A small distance 17 is embodied between the inner wall 4 and the radial outer end of each bar 16. This distance is normally on the order of magnitude of 1 to 2 mm. However, it depends on the powdered material and the liquid that is to be mixed with the powdered material. During this mixing, a type of dough can be produced for example which sticks to the inner wall 4, wherein a thickness of the dough that is greater than the distance 17 is formed. The distance 17 is then set such that the dough is exchanged. In the case of a small distance 17, the dough is sheared and worked and thus detaches from the inner wall 4 of the working space 3. Because of the small distance 17, a shearing force is produced which travels over the distance 17 all the way to the inner wall 4 of the working space 3 so that the entire dough is kneaded.

(14) In some cases, the intention is not for dough to be produced, but rather merely for the powdered material to be moistened. In such situations, it may be beneficial to select a different distance.

(15) The bars 16 are, when the sequence thereof is viewed parallel to the direction of the axis 10, arranged chaotically or irregularly offset from one another in a circumferential direction. Thus, it is avoided that one bar is moved in the wake of another bar and a drip edge on one bar impedes the formation of the mixture of the powdered material and liquid on the following bar. The powdered material and the liquid will mainly accumulate at the radial outside. However, even at this position a drip edge can then form at the end of the bar trailing in the circumferential direction or rotation direction, which drip edge can subsequently impede the next highest or next lowest bar in an axial direction, that is, a bar that is more distant from or more proximate to the outlet 12. This chaotic arrangement can be defined, for example, as adjacent bars 16 respectively comprising an angular distance between one another in a circumferential direction, wherein a first angular distance differs from an adjacent, second angular distance. The first angular distance can for example be positive and the second angular distance can for example be negative. The absolute value of the two angular distances thereby does not need to be equal.

(16) As can be seen in FIGS. 1 and 2, the bars 16 are arranged solely on the side of the blade ring 7 facing away from the feed opening 11.

(17) As mentioned above, the outlet 12 is arranged at the bottom end of the housing 2.

(18) A bar 16a adjacent to the outlet 12 comprises a bottom edge 18 that is flush with the outlet 12, more precisely, with a bottom edge 19 of the housing 2. The bottommost bar 16a thus works the powdered material sticking to the inner wall 4, which material is already mixed with the liquid, all the way to the bottom end 19 of the housing 2. At the outlet 12, it is also not possible for a ring of the dough or of the mixture of powdered material and liquid to form.

(19) An outlet section 20 connects to the outlet 12. The outlet section 20 comprises a radial recess 21 in an outward direction across from the outlet 12. This recess 21 corresponds at least to the thickness of a wall of the housing 2, which wall surrounds the working space 3. The mixture of powdered material and liquid conveyed away from the inner wall 4 by the bottommost bar 16a will deviate radially outwards onto this recess 21 when the mixture moves downwards in the direction of gravity. The recess 21 constitutes a surface that is aligned perpendicularly to the direction of gravity. At this position, the adhesive strength for the mixture is smaller, as a consequence of which the mixture fails or slides downwards in the direction of gravity more or less on its own.

(20) The outlet section 20 can be formed from an elastic material, for example, by a tube 22 of an elastic plastic. If a larger amount of the mixture accumulates below the outlet 12 in the outlet section 20, then this causes the outlet section 20 to bulge outwards, so that the inside 23 of the outlet section 20 in turn obtains a surface component that is perpendicular to the direction of gravity, as a result of which the mixture can easily detach from the inside 23.

(21) Alternatively or additionally, it can also be provided that the outlet section 20 widens away from the outlet 12 in a radial direction. In this manner, an adhesion of the mixture to the inner wall 23 of the outlet section is also only possible up to a certain limit. Once the mixture exceeds a critical mass, the weight of the mixture is so large that it slides or falls downwards in the direction of gravity.

(22) Additionally and alternatively, it can also be provided that the outlet section 20, at least on its inside 23, comprises a non-stick surface. The non-stick surface can be formed from the material of the outlet section 20 itself. However, the non-stick surface can also be formed by a coating.

(23) The rotor 5 rotates at several hundred revolutions per minute, preferably at 1000 to 1500 revolutions per minute, so that a dwell time of 20 to 30 seconds results for the powdered material that is mixed with liquid in the course of the process.

(24) The apparatus 1 functions as follows:

(25) Powdered material that is supplied through the feed opening 11 falls, under the effect of gravity, onto the blade ring 7, more precisely, onto the blades 8 rotating at this position. Part of the powdered material can pass through the gaps 9 between the blades 8. However, due to the relatively high rotational speed of the rotor 5, a majority of the powdered material will impact the blades. On impact with the blades 8, centrifugal force is applied to the powdered material and the material is conveyed radially outwards until it comes into contact with the inner wall 4 of the working space 3. Under the effect of gravity, a layer of the powdered material then slides downwards along the inner wall 4.

(26) This layer of the powdered material is then wetted by the liquid exiting the annular gap 13. During this wetting, this layer is impinged upon by the bars 16. The layer is thicker than the distance 17 of the layer. The bars 16 then perform a type of kneading operation, which leads to a thorough intermixing of the liquid and the powdered material. Because the bars 16 overlap one another in an axial direction or at least connect to one another in an axial direction, it is not possible for a layer ring that would hinder the layer's further descent to remain on the inner wall 4 of the working space 3. Overall, the dough or the mixture of the powdered material and the liquid thus subsequently moves downwards to the outlet 12 due to the effect of gravity.

(27) At the outlet 12, the layer is also impinged upon by the bottommost bar 16a and scraped off of the inner wall 4. With the specific embodiment of the outlet section 20, as described above, it is also not possible for any clogging to result at this position.

(28) The apparatus 1 can be used, fear example, to mix flour and water in order to produce a dough.

(29) However, other powdered materials can also be mixed with other liquids. Thus, it is for example possible to make a cocoa powder dust-free by mixing the cocoa powder with a fat, for example, oil. By mixing cocoa powder with the fat, relatively large agglomerates are produced, or said agglomerates can be produced. These agglomerates are then broken down again into smaller and fine agglomerates by the rotating bars 16. The size of the agglomerates can be defined with the bars 16 and the arrangement thereof.

(30) Another possible application would be the production of effervescent powder. In this case, powdered sugar is mixed with water and flavorings. Here, agglomerates are then also produced which can be subsequently dried on a dryer section, where the water is evaporated. The effervescent powder is thus stabilized.

(31) If fat is used as liquid, essentially only a heated rotor and/or a heated housing are necessary. The heating device required therefor, or the heating devices required therefor, are not illustrated in the drawing for the sake of clarity.

(32) It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.