EP1050335A1 - Spherical mixer - Google Patents

Abstract

The mixer has a transmission tube (70) mounted in rotation, a first axle (80) mounted in rotation inside the transmission tu and a second axle (76) mounted in rotation at the end of the transmission tube and supporting the mixing device (78). The second axle forms an angle alpha with the axis of the transmission tube and is driven in rotation about its own axis by the rotation the first axle. Preferred Features: The angle alpha is 45-90 degrees . The orientation of the mixing device can be varied relative to the second axle during its rotation and are in the form of segments of a circle. A first motor (66) drives the first axle and a seco motor (68) drives the transmission tube. The second axle is driven by the first axle via a gear. An Independent claim is also included for a mixing apparatus containing a mixer as above and a receiver (60) with a symmetr revolution described by the edge of the mixing device. The receiver has an outlet drain in its base.

Description

The subject of the invention is a device for mixing and / or homogenization of a heterogeneous medium.

Mixers are used to mix several components. These can be gaseous, liquid or solid and miscible or immiscible. The mixture is an operation that occurs in all types of industry, which gives it a considerable importance.

"Mechanical unit operations", Course handout from E.N.S.I.C. 2nd Midoux Christmas Year, 1989, describes mixers including a tree on which mixing devices are attached. Organs can have various forms, such as blades, propellers, anchors, screws or ribbons. The shaft is rotated by a means of training. The mixing elements of the mixer are immersed in a container containing the medium to be mixed. The speed of movement imparted to medium being variable in the medium, the mixture of the heterogeneous medium is obtained. The tree can plunge vertically into the container with the mixing elements turning horizontally, or it is introduced laterally into the container and the organs rotate vertically. For some applications, the tree can be inclined to rest on the edge of the tank. In all cases described in this document, the mixing elements rotate around the axis defined by the shaft.

There are also known mixers having two axes. Some robots household appliances thus have a small tank. The rotational movement of the shaft central is then transmitted on the one hand to a second offset shaft so that it performs a planetary movement around the central shaft; the mixing bodies are mounted on the second shaft, and are thus rotated around it second tree at the same time as the tree describes a circle.

EP-A-0 325 865 describes a mixer, which has a motor mounted on the cover of a tank, a first vertical shaft driven in rotation by the motor, a second vertical shaft, supported by the first shaft and rotating around it, and a third horizontal shaft supported by the second shaft on which are mounted mixing devices. This mixer works in a flat bottom tank, and is designed so that the mixing elements sweep the bottom of the tank without leaving any area dead.

The object of the invention is to improve the performance of existing mixers. The object of the invention is also to solve the new problem of dead zones in mixers. Indeed, if the mixer is not suitable for the container geometry, there are areas called dead zones, in which the middle remains at rest. In these areas, no mixing takes place. he is also possible that a mixed volume in such a dead zone will separate from new. This problem is particularly encountered for the lower corners of cylindrical containers for example. This problem of dead zones and uniformity of mixing is all the more sensitive when it comes to mixing a viscous medium or mix on low speed. In these cases, the effects of mixing are limited to the area swept by the mixing devices. We can then obtain a non-uniform mixture if the mixer is not suitable for the geometry of the container. The invention provides a solution to this problem of dead zones, in particular in the case of containers spherical.

EP-A-0 325 865 proposes a solution to the problem of dead zones, which is suitable for a flat bottom container. However, the solution proposed in this document is not necessarily satisfactory for the top of the product to mix; little or no mixed areas may remain in the upper part of the container.

The mixer of the invention is also particularly suitable for mixing immiscible constituents having a different density; it avoids the separation of the constituents of the mixture under the effect of the difference in density of constituents. The mixer of the invention is also suitable for mixing a medium comprising fragile constituents whose texture is desired to be preserved.

The invention also makes it possible to mix in a container, while continuing the mixing or homogenization operation until emptying complete container. It avoids untimely incorporation of air into the mixture as well as splashes, which lead to fouling which can cause the immobilization of the device to perform tedious cleaning.

The invention applies to the mixture of media of all types, and in particular of viscous or powdery media. The mixer of the invention is particularly suitable for maintaining unstable mixtures, even in the presence of components fragile. Finally, the mixer according to the invention is particularly advantageous in that that it can be adapted to the geometry of containers of various shapes. In addition, the mixer of the invention makes it possible to maintain the mixing action or homogenization until the container is completely emptied. It ensures a mixture particularly soft and also prevents splashing and incorporation of air in the mixture.

The invention provides a mixer, comprising a mounted transmission tube rotating, a first shaft rotatably mounted inside the transmission tube, a second shaft rotatably mounted at the end of the transmission tube and supporting mixing members, the second shaft forming an angle with the axis of the transmission and being driven in rotation about its own axis by the rotation of the first tree.

Preferably, the angle between the second shaft and the transmission tube is between 45 ° and 90 °.

It is advantageous that the mixing members have an orientation by compared to the second variable tree during its rotation.

In one embodiment, the mixing members have an edge end in the shape of a circle segment.

We can also provide a first motor rotating the first shaft and a second motor rotating the transmission tube.

It is also possible that the second shaft is rotated by the first tree through a gear.

The invention also provides a mixing device comprising such a mixer and a container whose bottom has a symmetry of revolution and whose generator is the end edge of a mixing element.

Advantageously, the container has a drain opening in the bottom. We can then choose the said angle so that the end of a mixing member sweeps the drain opening.

In a last embodiment, the device also has a cradle inside supporting the container and the mixer and mounted on an outside cradle rotation along a common diameter of the inner and outer cradles, and a support, the external cradle being rotatably mounted according to a diameter on the said support.

• figure 1, un schéma de principe d'un mélangeur selon l'invention avec son récipient;
• figure 2, une vue en coupe d'un mélangeur selon un premier mode de réalisation de l'invention ;
• figure 3 une vue de dessus du mélangeur de la figure 2 ;
• figure 4 une vue à plus grande échelle d'un mélangeur selon un autre mode de réalisation de l'invention;
• figure 5 une vue d'encore un autre mode de réalisation de l'invention;
• figure 6, une vue d'un autre mode de réalisation de l'invention.

Other characteristics and advantages of the invention will appear on reading the following description of embodiments of the invention, given by way of example and with reference to the appended drawings which show:

• Figure 1, a block diagram of a mixer according to the invention with its container;
• Figure 2, a sectional view of a mixer according to a first embodiment of the invention;
• Figure 3 a top view of the mixer of Figure 2;
• Figure 4 an enlarged view of a mixer according to another embodiment of the invention;
• Figure 5 a view of yet another embodiment of the invention;
• Figure 6, a view of another embodiment of the invention.

The invention proposes, to improve the performance of known mixers, to arrange the rotating mixing members on a shaft which itself rotates in the middle, and which is oriented in a substantially horizontal direction. Of the so we avoid any dead zone in the container in which the mixing takes place, without any fixed point of the mixing members in the vicinity of the wall of the container.

In the embodiment of Figures 1 to 5, the tree on which are arranged the mixing members is supported by a substantially vertical shaft, which is driven in a rotational movement on a circle. Kinematics is the same type as that of document EP-A-0 325 865, but the invention proposes improvements to the principle proposed in this document.

In the embodiment of FIG. 6, the tree on which the mixing members is supported by a substantially vertical shaft, which is driven rotating around its own axis. This embodiment simplifies considerably the structure proposed in document EP-A-0 325 865, and including simplifying the drive mechanism.

Figure 1 shows a block diagram of a mixer according to the invention. The mixer has a first substantially vertical shaft 1, which supports the mixing bodies, and which as symbolized by the arrow, is rotated. AT its lower end, the shaft 1 supports a second shaft 2. In the mode of embodiment of Figure 2, the shaft 2 is substantially vertical, and is offset from to the first tree. The second shaft 2 is rotated around the first shaft 1. The second shaft 2 carries at its lower end a third shaft 3 oriented in a substantially horizontal direction. Tree 3 carries the organs of mixture, represented here in the form of blades 4 and 5. These blades are driven in rotation around the third tree, and allow the medium to be mixed in container 6.

In this way, in operation of the mixer of the invention, the organs of mixture are driven in a rotational movement around an axis substantially horizontal, this axis itself being rotated in the middle.

Thus, the first shaft 1 is rotated by means training. The second shaft 2 is rotated around the first shaft 1, but also around itself. The second shaft 2 carries at its end lower a third shaft 3 substantially horizontal which carries the organs of mixed. The third shaft 3 is rotated, which leads to rotation mixing devices. The preferred embodiment provides for the training of three shafts by a single motor coupled to shaft 1. However, it can also be advantageous to provide independent training for another or even all trees. If we also consider the satellite movement of the tree 2 around the tree 1, it can be seen that the ends of the mixing members describe a sphere when the center of rotation of the mixing members coincides with the axis of the shaft 1 and a torus in cases where this center is offset from this axis. By center of rotation the intersection between the axes of symmetry of the blades - if they exist - and the third tree.

As shown in the figure, the shape of the blades 4 and 5 can be adapted to the shape of the container, so as to minimize dead zones in the container. Because of rotation around the third substantially horizontal axis, there is no fixed point near the wall of the container. Due to the rotation of the second tree around the third shaft, the third shaft is rotated in the container, and the axis of rotation of the mixing members rotates in the container. The bottom of the container according to the invention therefore has a symmetry of revolution - around the axis of the first shaft - and its generatrix is the end edge of the mixing members; in For example, the bottom of the container is spherical, and the edge of the blades is an arc.

In the embodiment of FIG. 1, each of the mixing members is symmetrical about a straight line. The intersection between this straight line and the tree 3 is found on the axis of the first tree 1, symbolized in the figure by a dotted line. This configuration is particularly advantageous in the case where the organs of mixture are rotated on themselves, in addition to their rotation around tree 3.

It is also possible that the mixing elements are not in the axis of the first tree 1. This can in particular be advantageous for increasing the volume swept by the mixing bodies.

Figure 2 shows a sectional view of a mixer according to a first mode of realization of the invention; in the embodiment of FIG. 2, the movement of the second tree around the first, and the movement of the mixing bodies around of the third tree are provided by unique drive means; these means single drive rotates the first shaft, which presents the advantage that the drive means are not in motion during the mixer operation.

We find in Figure 2 the different elements already described with reference to the Figure 1, including the first tree 1; this tree is rotated by drive means - for example a variable speed gearmotor - no shown in the figure. At the bottom of the first shaft 1 is rotatably mounted a support 10, in which the second shaft 2 is mounted for rotation. Support 10 maintains the position of the second tree relative to the first tree, while allowing the rotation of the second tree around the first tree.

A first toothed wheel 11 is rotatably mounted around the first shaft, and is held fixed relative to the container 6 by a locking rod 12. In this way, the gear is fixed. A second toothed wheel 13 is fixed on the second shaft 2 and meshes on the first gear. The first and second gear wheels form a first gear.

A third gear 15 is fixed on the first shaft. A fourth wheel gear 16 fixed on the second shaft meshes on the third gear. The third and fourth gears form a second gear.

The assembly of the support 10, the first and second gears are arranged in a housing 19.

The operation of the elements which have just been described is as follows. The rotation of the first shaft 1 is transmitted to the second shaft 2 via the second gear; due to the first gear, the second shaft is driven in rotation around the first tree. The choice of the numbers of teeth from the first to fourth toothed wheel allows to adjust the own rotation speed of the second tree, and the speed of rotation of the second tree around the first tree.

On the lower side of the support 10 is vertically fixed a tube of transmission 25 surrounding the second shaft 2. At the lower end of the tube transmission 25 is fixed a casing 40, in which the lower end of the second shaft is rotatably mounted. At the lower end of the second tree is fixed a fifth gear 27, with conical teeth. The third shaft 3 is mounted at rotation in the housing 40, and carries at its end a sixth toothed wheel 28, bevel gear, which meshes on the fifth gear. The fifth and sixth gearwheels form a third gear.

The blades 4 and 5 are fixed on the third shaft.

In this way, the rotational movement of the support 10 rotates the casing 40 around the first shaft 1. The proper rotation movement of the second shaft 2 is transmitted to the third shaft 3 by the third gear, and drives the mixing devices. The choice of the ratio of the numbers of teeth in the third gear allows to adjust the own rotation speeds of the second and third trees.

In the illustrated embodiment, the mixing members are mounted on rods 21 and 22, and are symmetrical with respect to the axis of these rods. Point of intersection of the stems and the third tree is on the axis of the first tree 1. The number and shape of the blades depends on the mixing problem to be solved. In the embodiment illustrated in Figures 2 and 3 are provided 4 blades. Advantageously, the orientation of the different blades can be adapted to the problem of mixed; in particular, it is possible to vary this orientation with the angle of rotation, as explained with reference to Figure 4.

As a result, the mixing members perform both a movement of vertical rotation, around the third tree, which itself is animated by a movement horizontal rotation in the fluid. These movements lead, if the centers of these two rotations intersect, to a movement on a sphere of each of points of the mixing organs. According to the preferred embodiment, the center of rotation of the mixing elements is in line with the axis of the first tree, and the ends of the. It is also possible that the mixing elements are not in the extension of the shaft 2, but are offset horizontally. In this case, each point of a mixing member moves on a torus. According to a advantageous embodiment, the shape of the mixing members is adapted to the geometry of the bottom of the container used. Organs with curved ends corresponds to a segment of a circle are particularly advantageous. This allows to obtain an optimal mixing efficiency insofar as the zones are avoided dead in containers with hemispherical bottoms or similar.

Figure 3 shows a top view of the mixer of Figure 2. We recognize in Figure 3 the first shaft 1, the first gear 11 with the locking rod 12, the second gear 13, the third gear 15 and the fourth gear 16. The blades 4 and 5 are also seen in the figure, with the support rods 21 and 22. Arrows 31 and 32 indicate the rotation of the support 10 and the third shaft around of the first tree. Arrows 33 and 34 indicate the rotations of the third and fourth gears 15 and 16. Arrows 35 and 36 indicate the rotation of the second gear, and the rotation of the second shaft around the first shaft.

According to the preferred embodiment of Figures 2 and 3, the speed of rotation relative of the three trees is fixed, and determined by the relationships of the different gears. It may however prove advantageous to provide means allowing to vary these respective speeds. In this case, means can be provided independent training for each tree. Computer control different motors can also be advantageous, for example in the case where it is desired to vary the speeds during mixing or frequently.

Figure 4 shows a detail of another embodiment, in which the device according to the invention further comprises a cam system making it possible to make vary the orientation of the mixing elements according to the angle of rotation of the third tree.

To this end, a fourth shaft 41 is provided inside the third shaft 3, which is fixed relative to the casing 40, as symbolized by the connection 42 at the end of this fourth tree. At its end remote from the housing, the fourth shaft has a wheel 44, with on its perimeter a raceway 45 which has a axial extension along the axis of the fourth shaft.

In the embodiment of Figure 4, the blades are rotatably mounted on the third tree; as shown in the figure, the rod 21 of the blade 4 is mounted at rotation in a radial bore 47 of the third shaft.

At its end opposite to the blade, the rod 21 has an offset offset follower 49, which rolls in the raceway 45 of the wheel 44. The angular position of the rod 21 relative to the third shaft, and therefore the angular position of the blade 4 around the rod 21 depends on the position of the follower 49.

The device of Figure 4 operates as follows. Rods 21 or 22 and the corresponding blades are rotated around the axis of the third shaft 3 by the rotation of the third shaft relative to the casing 40, due to the concomitant rotation of the bores in which the rods are mounted. During this rotation, the followers 49 roll in the raceway, and the fact that the raceway extends in different positions along the axis of the fourth shaft, vary the angular position of the rods, and therefore of the blades.

The device of Figure 4 allows in this way to change the angle between the blades and the third shaft, during the rotation of the blades around the axis of the third tree. An appropriate raceway allows for example to enter the mixing organs at an angle in the medium to be mixed and bring them out in knife, i.e. perpendicular to the surface, to minimize splashing and incorporating air. A 45 ° variation between the angle between the plane on the one hand, and the angle between the plane of a adjacent mixing member and the third tree on the other hand also constitutes a advantageous arrangement insofar as it causes a wave effect while causing the product by a bottom movement.

Figure 5 shows yet another embodiment of the invention; in the embodiment of the invention, the entire mixer and its container is mounted on two concentric cradles 51 and 52. The inner cradle supports the container and mixer; the mixer support is not shown in the figure. The inner cradle is mounted on the outer cradle to rotate according to a diameter common interior and exterior cradles; in the figure, this diameter is perpendicular to the plane of the sheet. The outer cradle is rotatably mounted on a support 53, rotating along a diameter of the outer cradle perpendicular to the diameter on which the inner cradle is mounted. The set of two cradles allows you to position the container and the mixer at any angle. The figure also shows the drain opening 54 located at the bottom of the container.

In the embodiment of the figure, the two cradles are concentric at a point which is the intersection of the axes of the first and third trees. We could also choose another fixed point for all the mixers.

The assembly of FIG. 5 makes it possible to combine a rotational movement of the container and mixer, with the movement of the mixing members. In this way, dead masses are avoided, and the deposit of mixed material on the walls of the container. This allows in particular to avoid the use of a scraper.

The device of the invention is suitable for the rapid and efficient mixing of liquid or solid materials, for example powders. We give below the results of mixing tests in an apparatus of the type of that of FIGS. 2 and 3, for a mixture of saccharin in milk powder or in flour.

In the first test, 100 g of saccharin and 8679 g were mixed. milk powder in the blender for 180 seconds. Then, three samples were taken from different areas of the mixing container and analyzed. The results of the tests are shown in Table 1 Saccharin (g) Milk powder (g) % 0.10 10.75 0.93 0.13 10.86 1.19 0.11 10.85 1.01

These values are to be compared with the nominal percentage of 1.15% of saccharin in milk powder. They show that the mixture is very homogeneous after a short mixing time.

In the second test, 100 g of saccharin and 10454 g were mixed. flour in the blender for 240 seconds. Then, three samples were taken from different areas of the mixing container and analyzed. The results of the tests are shown in Table 1 Saccharin (g) Flour (g) % 0.075 11.09 0.67 0.057 10.49 0.54 0.064 10.48 0.61

These values are again to be compared with the nominal percentage of 0.95 % saccharin in flour. They are indicative of the separation of constituents, which is reached after a very short mixing time. It is indeed known that prolonged mixing can lead to separation of constituents initials: such separation generally takes place after a very long mixing time greater than 240 seconds.

The mixer of the invention has also proved to be particularly suitable for the making jams. Thus, we frequently observe that at rest, the pieces fruit, of lower density, rise to the surface of the mass of jam. It is then necessary to homogenize the mixture continuously during packaging in order to obtain a homogeneous final product, i.e. an equivalent quantity of pieces fruit in each jar of jam. In the example cited, however, we wish keep the texture of the pieces of fruit despite the mixture. It is therefore important that the mixing is done in a delicate way, without destroying the texture of the pieces of fruit, without incorporating air and without splashing. The mixer of the invention has allowed to obtain a great homogeneity of the distribution of the pieces of fruit, while preserving the texture of the pieces of fruit.

FIG. 6 shows another embodiment of a mixer according to the invention. In this embodiment, as indicated above, the tree on which are arranged the mixing members is supported by a substantially vertical shaft, which is rotated around its own axis. More specifically, we recognize on FIG. 6 the container 60, provided with a cover 62 provided with inlet means for product. As in the embodiments described above, the container is spherical bottom, and has an opening in the bottom. On the cover is mounted a casing 64, on which two motors 66 and 68 are fixed. The first motor makes it possible to adjust the speed of rotation of the mixing elements around their axis of rotation, while the second motor adjusts the speed of rotation of the shaft supporting the mixing members around the axis of symmetry of the container. The presence of two motors allows these two angular speeds to be adjusted separately; as described above, we might as well just plan for one motor, and one gear system to ensure the two rotations. This last solution presents the advantage of using only one motor, but it makes variations more complex relative speeds of rotation.

Under the cover is rotatably mounted a transmission tube 70; we see on the figure the bearings supporting the transmission tube. The transmission tube is rotated by the second motor 68, via a gear of two toothed wheels 72 and 74. In the example, the transmission tube has an axis of rotation which is confused with the axis of symmetry of the container, but this is not essential for the implementation of the invention, and it could be otherwise, especially in the case of a flat bottom container. At its lower end, the tube transmission supports in rotation the shaft 76 which carries the mixing members 78. As shown in the figure, the axis of this shaft is inclined relative to the tube transmission of an angle a which in the embodiment of the figure is close to 78.5 °. More generally, it is advantageous for this angle to be between 45 ° and 90 °. The upper limit of this range is dictated by the size of the organs of mixture, which as shown in the figure must pass in the vicinity of the transmission in the upper part of the mixer, in the case of a 90 ° angle, the mixing members advantageously have a variable orientation, so to disappear when passing near the transmission tube, as explained below. Yes the orientation of the mixing elements is fixed, it is advantageous to choose the size of the mixing bodies and the orientation of the second shaft so that the bodies of mixture pass as close as possible to the tube; this ensures a good sweep of the bottom of the container.

The lower limit of this range ensures that the mixing elements sweep the bottom of the container, especially in the vicinity of the emptying point thereof. The rotation of the transmission tube under the drive of the second motor ensures that the shaft 76 is rotated around the axis of the tube transmission.

In addition to this rotational movement, the shaft 76 which carries the mixing members is animated by a rotational movement around its axis. For this purpose, the mixer has a shaft 80 rotatably mounted inside the transmission tube, which is driven in rotation by the first motor. At its lower end, this tree is provided with a bevel gear 82, which meshes with a gear 84 mounted on tree 76.

The operation of the mixer of FIG. 6 is as follows. The tree 80 or first shaft is rotated, and rotates around its axis. The tube transmission rotates at the same time around the axis of the first shaft. Because of the rotation of the transmission tube, the shaft 76 or second shaft is rotated around the axis of the shaft 80 and of the transmission tube. Simultaneously, the rotation of the first shaft 80 ensures the rotational drive of the second shaft around its own axis. In this way, as in the first embodiment of the invention, the mixing bodies are rotated around an axis substantially horizontal, this axis itself being rotated in the middle.

As shown in the figure, and as in the previous embodiments, the shape of the mixing members can be adapted to the shape of the container, so that minimize dead spots in the container. Due to the rotation around the second substantially horizontal axis, there is no fixed point in the vicinity of the container wall, especially near the bottom of the container. Because of the rotation of the second tree around the axis of the first tree, the second tree is rotated in the container, and the axis of rotation of the mixing members spins in the container. The bottom of the container according to the invention therefore has a symmetry of revolution - around the axis of the first tree - and its generator is the end edge of the mixing members; in the example, the bottom of the container is spherical, and the edge of the blades is an arc.

The embodiment of Figure 6, compared to the embodiments previous, simplifies the structure of the mixer, and in particular the number moving parts. This embodiment preserves the advantages described in reference to the previous figures, such as the absence of a dead zone, the quality of the mixed. We can combine the embodiments of Figures 4 and 6, and provide vary the orientation of the mixing elements during the rotation around the second tree. In this case, due to the asymmetry of the organs of mix pay attention to the orientation of the mixing bodies in the vicinity of the bottom of container.

Note that all of the moving parts are either in the container, either in the cover casing.

Of course, the present invention is not limited to the examples and methods of realization described and represented, but it is susceptible of numerous variants accessible to those skilled in the art. Likewise, it is clear that the invention is not limited to the preferred embodiment. In particular, in the embodiments described, the whole movement is transmitted to the different parts of the mixer, by the intermediary of the first tree; this solution has the advantage of allowing mount the mixer drive motor in a fixed position, which limits the moving masses. We could also provide a first fixed shaft, and a motor driving the second tree. In the embodiments described, the trees are perpendicular; one could also foresee that the second tree is inclined relative to at the first tree, for example to increase the volume likely to be swept by the mixing organs.

Although this is not described in detail, the teaching of Figure 5 - a set of two concentric cradles - to the mixer of the Figure 6, or elsewhere to other types of mixers.

In the embodiment of FIG. 6, the transmission tube could be extend lower than the second tree. However, this would not affect functional, and even then the second tree would be found functionally at the end of the transmission tube; the part of the tube transmission projecting beyond the second shaft does not occur in the training.

Claims (10)

Mixer, comprising a rotationally mounted transmission tube (70), a first shaft (80) rotatably mounted inside the transmission tube, a second shaft (76) rotatably mounted at the end of the transmission tube and supporting mixing members (78), the second shaft (76) forming an angle (α) with the axis of the transmission tube and being rotated about its own axis by the rotation of the first tree. The mixer of claim 1, characterized in that the angle (α) between the second shaft and the transmission tube is between 45 ° and 90 °. The mixer of claim 1 or 2, characterized in that the mixture have an orientation relative to the second variable tree during of the rotation of it. The mixer of claim 1, 2 or 3, characterized in that the mixture (78) have an end edge in the form of a circle segment. The mixer of one of claims 1 to 4, characterized by a first motor (66) driving in rotation the first shaft (80) and by a second motor (68) causing the transmission tube (70) to rotate. The mixer of one of claims 1 to 5, characterized in that the second shaft (76) is rotated by the first shaft through a gear (82, 84). A mixing apparatus comprising a mixer according to any one of claims 1 to 6, and a container (60) whose bottom has a symmetry of revolution and whose generator is the end edge of a mixing member. The apparatus of claim 7, characterized in that the container has a drain opening in the bottom. The apparatus of claim 8, characterized in that said angle is chosen to so that the end of a mixing element sweeps across the drain opening. The apparatus of claim 7, 8, or 9, characterized in that it further has an inner cradle (51) supporting the container and the mixer and mounted on a outer cradle (52) rotating along a common diameter of the inner cradles and exterior, and a support (53), the exterior cradle being rotatably mounted on a diameter on said support (53).

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