US3674241A

US3674241A - Mixing machine

Info

Publication number: US3674241A
Application number: US63147A
Authority: US
Inventors: Wilhelm Eirich; Gustav Eirich
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-08-16
Filing date: 1970-08-12
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: ES382648A1; NL171538C; BE366702A; BE754675A; CA925073A; SE383686B; AT308055B; FR2058064A5; NL171538B; GB1320575A; CH517517A; NL7011408A

Abstract

Mixing machine with a plate- or dish-shaped container for the material to be mixed. A rotating mixing tool is accommodated in the container so as to rotate about an axis eccentric to the axis of the container. The axis of the tool is forcibly caused to perform a relative movement in relation to the mixing plate. The mixing tool comprises a flat disc-like rotary element which is arranged at the free end of its shaft. Rods are arranged in the rotary element which are substantially parallel or inclined in relation to the shaft. For higher speeds a ring is secured at the free ends of the rods which keeps the rods in place in spite of large centrifugal forces.

Description

United States Patent Eirich et al. 1 July 4, 1972 54] MIXING MACHINE 612,584 10/1898 Ferris ..259 179 1,095,980 5/l9l4 Eirich... P walldum" 3,339,897 9/1967 Davis ..259/96 Gustav Elnch, l9 Bahnhofstrasse, both of Hardhe'mmordbaden' Germany Primary ExaminerRobert W. Jenkins 2 2 1 Attorney-McGlew and Toren 21 Appl N6; 63,147 57 ABSTRACT Mixing machine with a plate or dish-shaped container for the [30] Foreign Application Priority Data material to be mixed. A rotating mixing tool is accommodated in the container so as to rotate about an axis eccentric to the 1969 Germany 19 831'6 axis of the container. The axis of the tool is forcibly caused to [970 Germany 20 02 6419 perform a relative movement in relation to the mixing plate, The mixing tool comprises a flat disc-like rotary element [52] U.S.Cl ..259/l5, 259/84, 259/175 which is arranged at the f d f its Shaft Rods are "f 4 4 a 4 v 6 ranged in the rotary element which are substantially parallel 1 Field of Search 159/1 169, or inclined in relation to the shaft. For higher speeds a ring is 1 35 secured at the free ends of the rods which keeps the rods in place in spite of large centrifugal forces, [56] References Cited 26 Claims, 10 Drawing Figures UNITED STATES PATENTS A 3,420,507 1/1969 Eiri i n ..259/l79 PATENTEDJUL 4 m2 SHEET 10F 6 fivmwroP WILHELH EFRJCH Gurrnv Efhcu PATENTEDJUL 4:912 3.674.241

sum ear 6 Gus'mY Erma 3 a a x Em [Mia-M074 PATENTEDJUL 41m SHEET 3 BF 6 .9 ban [wrap WILHELH Emma Gun-ml Em 3y 5 m MIXING MACHINE The present invention is concerned with a mixing machine with a plate-shaped container for material to be mixed in which is accommodated at least one system of mixing tools which rotates about an axis eccentric to the axis of the container and comprises rods. The axis of said mixing tool system is forcibly caused to move relative to the mixing plate.

Progressive discoveries in the field of solid-state chemistry, and the constantly widening problems which are encountered imposed requirements on mixing machines (with respect to the energy input in the mix material) which render it necessary to make use of all directions of movement of the mix material in the mixing container, with simultaneous rapidly acting energy input.

A known form of mixing tool system takes into account the rapid input of energy into the mix material which is an indispensable requirement for an effective breakdown and a thorough mixing. This tool system consists of rods which are spaced at intervals, axially parallel to a drive shaft, and connected therewith by means of rods which extend at right angles to the drive shaft. Practice has shown that this arrangement satisfactorily fulfils the task assigned to it; that of rapid energy input. However, no movement of the mixing material can be produced therewith, inside the mix material container, other than one which runs parallel to the bottom of the vessel.

Subsequently, another arrangement has been developed and has become known; it differs from the construction described above, in that the rods are arranged at an angle to a drive axis in such manner that the rods diverge, viewed from the end of the drive axis. The rods also carry additional sheetmetal guide-plates which influence the movement of the mix material. This arrangement favors a drawing-in of the mixing material at the upper end of the mixing tool, and encourages delivery at the lower end Thus there has been produced a further direction of movement of the mix material, in addition to the movement parallel to the bottom of a mix material container. However, due to its possible load capacity, this arrangement has constructional limits which mean that it is only possible further to increase the rotation speed so far achieved, by undertaking very high apparatus-technological expenditure. This again reduces the effectiveness of the known arrangement.

The invention, on the other hand, provides remedies to these problems, and it is characterized in that the mixing tool system comprises a flat rotary element which is arranged at the free end of the shaft of the mixing tool system and which accommodates therein rods which are substantially parallel or inclined in relation to the shaft.

The mixing tool system according to the invention removes the limit on the energy input into the mix material per time unit, which was possible with the last-mentioned construction, in that the rods do not diverge, and yet the actual pumping effect of the known construction still is not lost. Surprisingly, it was found that a suction is produced, along the axis and in the direction onto the rotary element. In this way, the mix material is conveyed to the rods, radially outwardly, and is exposed to the highly intensive rebound effect of the rods. Thus the invention combines in itself the modes of working of the known devices, without having their peculiarities which are the result of their construction and which are quite acceptable for other cases of application. In comparison to the mixing tool systems previously known, a lower resistance is offered to the material which is to be treated, so that, with a comparable peripheral speed, the mix material is circulated substantially more strongly. The input of mix material per time unit is considerably increased. This increases in advantageous manner the specific energy input and the working capacity. It is universally applicable, but is quite particularly suitable for mix materials which are viscous and rigidly plastic and therefore difiicult to process.

For masses which are capable of flowing in the dry and liquid state, the invention is advantageously further constructed in such manner that the mixing tool system comprises a disc-shaped rotary element, connected to a free end of the rotary shaft of the mixing tools system, and of an annular rotary element arranged spaced at a distance apart from the other aforesaid rotary element and surrounding the shaft but spaced apart therefrom; the said two rotary elements being connected by means of rods arranged therebetween. Thus, in practice, a basket-like rod arrangement is formed, and the said basket-like rod arrangement sucks in the mix material at its annular-shaped end, through the gap formed there; said material then is conveyed to the disc-shaped rotary element, and there it undergoes a strong radial acceleration, and impacts at high speed onto the rods or beating elements which exercise a rebound effect. lfone considers the case of one particle of the mixing material, two unequally directed high energies of rotational and translatory nature meet, and dissolve the compounds of the particle of mix material within a shortness of time never achieved until now. The particles of the mix material not only undergo the stresses which have been mentioned; they are also strongly accelerated at their discharge from the tool according to the invention, and are shot at high speed into the layer of material which surrounds the tool. By this means, an autogenous grinding is effected within the material layer, which additionally contributes to the dissolving of the compounds.

The movement of the mix material, which is induced by the rotation of the mix material container in connection with the mixing tool system, and which brings about the mixing, and which runs parallel to the bottom of the mix material container, is superimposed with the mixing movement which is the result of the pumping action and which runs approximately vertically thereto. Thereby the overall movement is intensified, so that, with the constructions according to the invention, the homogenization is improved, so that an even better efiect can be achieved within a relatively short time. However, the pumping action also contributes extensively to the breakdown of the material, since, due to the strong suction effect, the particles of the mix material are pushed towards one another, whereby the autogenous grinding effect is intensified.

The invention is further developed in advantageous manner if the rods in the disc-shaped rotary element are arranged along a circular are which is concentric to the rotation axis, and are fastened unilaterally in the rotary element. The first feature of the advantageous development results in a running which is free of imbalance, such as is desirable in mixing tool systems which rotate at high speeds, for purposes of saving wear on the bearing of the tool system. The second feature allows an optimum pumping action to become effective unilaterally of the rotating element.

Another advantageous embodiment of the device according to the invention is characterized in that there is provided inside the mix material container, at least one tool system which is driven about an axis which is eccentric to the axis of the mix material container, in the same direction as, or contrary to the direction of, the rotation of the mix material container, and which carries mixing blades and which has a discharge opening in the baseplate over which said tool system engages. This embodiment is particularly suitable in cases where, in addition to the movement of the mix material already described, an additional extensive displacement of the mix material is desired, inside the mix material container, such as is useful additionally to the continuous impacting of the energy-input tool. Moreover, the blades of the tool system serve not only for distributing the mix material over a large area, and for the continuous impacting; they also contribute decisively to the rapid emptying of the device according to the invention; this view point is just as important as that of a short-duration eflective mixing, since the saving on mixing time is cancelled-out by too long emptying times.

The combination of the rapidly running tool system with one which runs slowly is not necessary in every case. For example, the slowly running system is not necessary in the case of relatively small mixers with slopingly arranged plate. In that case, the presence of a high-rotation speed mixing tool system is sufficient, in the case of assembly in a plate-type mixer, with horizontally arranged bottom, there is likewise no need to have a slowly running system, if two or more high-rotation speed tool systems are being used, or if the machine operates continuously, so that there is no need for a rapid emptying in successive charges.

In a further development, the mixing machine according to the invention is characterized in that the axis of the mix material container is arranged inclined in relation to a horizontal plane, and the mix material container is adapted to be driven with a rotation speed which imparts to the constituents of the mix material a greater centrifugal force than their specific weight; and in that there is provided, perhaps on the outer wall of the mix material container, at least one deflecting-device which draws the mix material away from the centrifugal force and guides the mix material in the direction towards the middle of the mix material container; and in that the eccentric arrangement of the axis of the mixing tool system is such that said material can be conveyed into a stream of mix material which flows through the mix material container along a chord. This embodiment of a mixer differs from the aforementioned in that the mixing is induced primarily by means of the centrifugal force. Now, since the stream of mix material moves along a chord, the mixing tool system (viewed from the center point of the mix material container) may be arranged either in front of the stream of mix material, or behind it. According to the position of the mixing tool system relative to the path of movement, the mixing tool system is driven so as to rotate either in the same direction as the mix material container, or in the opposite direction thereto. This embodiment has the advantage that it requires a comparatively low apparatus-technological expenditure; however, the mixing and the breakdown are uniformly intense, since here too, rotational and translational energies come together, bringing about an effective breakdown with simul taneous optimum mixing and autogenous grinding.

In a further development, an angle is enclosed in a projection on a plane parallel to the axis of the mix material container, between the axis of the mix material container and the axis of the mixing tool system. This is particularly suitable in order that a greatest possible part of the flow of the material which is grasped by the guiding devices should come into the drawing-in area of the tool systems according to the invention. Due to the high circulation speed of the material in the mixer, a tool system according to the invention is particularly strongly impacted upon, so that large quantities of energy can be introduced into the material within a short time.

According to the invention, it is particularly advantageous if there are arranged in the mix material container two or more tool systems, one behind the other and/or opposite one another and offset in relation to one another, (viewed in the direction of rotation of the container) if desired, on different radii. In that case, the deflectors or deviating devices, which produce the stream of mix material, can be so arranged that each tool system undergoes a full impacting. For this purpose, one deflector will not grasp the whole width of the side wall of the mix material container, but on the contrary, the deflectors, which are preferably arranged one behind the other in a particular succession, are also offset in their width, in relation to one another, in such manner that the whole side wall is coated, but the mix material is divided into two or more streams.

The scope of use of the mixing machine according to the invention may be further widened, in that, with the machine, it is possible to undertake, simultaneously, a conditioning of the mix material, such as cooling, drying, heating and moistening, or chemical treatment. For that purpose, according to the invention, it is provided for, as a preferred embodiment, that the shaft of the mixing tool system is surrounded by a tube which reaches as far as the drawing-in of the rods and which is of smaller diameter than the diametral distance apart of the rods, and the casing of the machine is connected to a low pressure source. Additionally, the end of the tube which faces away from the drawing-in area can be connected to a line which conveys fresh air, steam, or hot air. It is also possible to introduce liquids alone, or in a desired combination with gases.

Due to the connecting of the tube to a source for gases, liquids, or particles of solid matter, it is achieved that by means of the vortex or eddy, located under the surface of the mix material and rotating at high speed, the particles of the mix material are coated on all sides by the stream of the gas, of the liquids, etc. conveyed through the drawing-in area, so that the desired treatment of the surface of the particles is completed within the shortest possible time. The combination of the cooling, drying, heating, gasification, pulverizing or moistening of the mix material, at the desired distances apart in time, provide the best pre-requisites for an acceleration of the process and for exact process control.

A particularly suitable case of application for the mixing machine according to the invention is that of the rapid cooling of foundry moulding-sand, for which purpose, up to now, different sorts of sand-treatment apparatuses have been used, such as a rapidly running elevator with widened elevator tube, cooling drums, and sand centrifuges. For cooling the moulding sand, it is also known to use a mixing machine wherein, on the rubber-coated wall of the fixedly arranged mixing plate, edge mills with steel rolling surfaces rotate, grinding the sand finely by means of rubbing; the sand is high centrifuged towards the edge mills by rapidly rotating blades. From a cooling ventilator, arranged adjacent to the mixing machine, air is driven, under low pressure, into an air chamber on the bottom of the mixer, and then under and through the mixing elements. This presupposes a fixedly arranged mixing plate, because the guiding of the cooling air distributor system through a rotating plate would give rise to extreme difficulties, especially since all the sliding/sealing places which are provided in the bottom of the plate would be exposed to a strong friction, due to the sand continuously eddying up. Since according to the invention, the centrifuging tool, which causes the eddy, projects into the mixing plate with the conveyor tube, from above, no difficulties arise in this connection, and it may be readily applied also to a rotating mixing plate. Also, the mixing tool system is very simple as regards its whole construction and therefore it can be easily dismantled and repaired in case of need.

According to the invention it is particularly favorable if a fixedly arranged supply tube is arranged so as to open into the drawing-in area of the rods. In many cases, the centrifuge or eddy-causing device acts as a pulverizer. Therefore, through the aforementioned tube, a stream of liquid may be introduced directly, without high pressure, into the annular space of the rods; then this stream is changed into a fine spray and is atomized, by the centrifuger or eddy device. Under the surface of the mix material, the liquid is most finely divided, by the centrifuging device, and is worked into the mass.

For the purposes of the invention, it has proved advantageous for the rods to consist of plates which are secured in the rotary element and which are radially directed and which taper upwardly, i.e., they are constructed similarly to ventilator baffles, so that they advantageously support the conveying of the gas stream. In a suitable embodiment, the plates are approximately trapezium-shaped, in fact the outer edges of the plates extend vertically to the plane of the rotating element, and their inner edges extend inclinedly upwardly, towards the outside, at an angle thereto. A rod type centrifuge with inclinedly arranged or with bent rods would likewise provide good results. If the rods of the centrifuge are directed not parallel to the centrifuge shaft, but inclinedly towards the out side, the upper cross section of inlet is increased and this, among other things, has a favorable effect. It is suitable for the trapezium-shaped plates according to the invention to have, at their free upper end, a rectangular prolongation in the region of which the tube projects into the cylindrical space which is bounded by the plates. For stiffening purposes, it is recommended to use plates which have a bent-over or angular outline, at their foot.

According to the purpose for which the machine is to be used, the tube which surrounds the tool shah can be connected to a suitable gas source. In the case of the cooling of moulding sand, the blowing-in of air, or the sucking-away of air, can be applied. In both cases, the sand, which is circulated at very high speed by the centrifuge, is passed through an air stream which likewise travels at high speed and each individual grain of sand is exposed to a very turbulent air eddying, so that any moisture present is vaporized, and heat is correspondingly absorbed. According to the invention, there are to be preferred casings for the mix material container which are substantially gas-tight, for connecting the interior space to a low pressure source, so that the air is sucked away, out of the mixing-plate space, and a low pressure occurs there. Simultaneously, in this way the outlet of dust or vapor is avoided, at the transition place between the rotating mixing plate and its casing. Since the outside air, which is sucked in through the tube, expands in the drawing-in region of the centrifuge, the cooling effect is increased, while when air is blown in, this air undergoes a temperature rise at the blower, due to compression, and therefore the temperature drop is lessened between the air and the material which is to be cooled. The excluding of the nuisance of dust and gas in the installation space, achieved when the sucking-away process is used, it particularly advantageous in cases when, for the treatment of the material, in addition to air or instead of air, chemically active gases or vapors are intended to be conveyed through the material.

If the mixing machine according to the invention is intended to be used for a stronger drying of the mix material, then hot gas, e.g., hot air, is suitably introduced through the tube. Of course, the higher the speed of the gas, the stronger is the transmission of heat onto the contact surfaces. Since the rapidly running mixing tool introduces considerable energy into the mixing material, when the particles rebound onto the rotating tool plates, a pulverizing of the particles occurs, and this offers the advantage (in contrast to the edge mill machine used up to now for similar purposes) that a greater layering height is applied, and therefore there is better exploiting of a mixing plate of the same diameter.

An advantageous application of the machine according to the invention consists, for example, in the fine breakdown of asbestos. In fact, practice has shown that in the pulverizing of pieces of coarse asbestos e.g., the waste material from the stamping-out of asbestos sealings or packings, or rock asbestos, a breakdown of the asbestos fibers occurs in a manner which is particularly kind to the material in the region of the basketlike rods of the centrifuging arrangement especially if additional air is introduced inside the circle of rods; and that together with the air stream which is emitted from the mixing chamber, fine asbestos fibers are discharged, which resemble a fine cottonwool. In the case of the processing of the waste material from the stamping-out of asbestos sealings or packings (which usually contain sheetmetal inlays between two layers of asbestos) a separating of the asbestos fibers from the metal parts occurs; the latter accumulate in the mixing vessel, and have to be discharged periodically, via the discharge opening, while the asbestos is discharged through the discharge tube.

In the production of very finely rubbed material also, starting out from materials consisting of coarse hard grains, this method of working proves extremely advantageous, since the breaking down of very fine particles in the amount of a few My, from the even coarser grain size, requires a relatively sharp air current, sufficient to overcome the adhering of the very fine particles to those of coarser grain size. The very fine released particles hover in the air and then are sucked upwardly. The cross section of the tube for their sucking-away must be so dimensioned that the air velocity only carries out the very fine particles which are required.

These grinding and breaking down processes may be performed not only continuously, but also periodically; if necessary, with simultaneous drying or cooling of the material which is to be treated.

The embodiment of the machine in individual cases is arranged in accordance with the task which is set, in each case, with regard to the mix material concerned. In principle, the possibility also exists of introducing the gases through the tube under high pressure, and simultaneously applying low pressure to the mixing chamber. In the case of cooling moulding sand or similar mix material, it may be suitable, in addition to sucking-in the air through the tube in accordance with the invention, to provide air inlet apertures in the side wall of the plate, near to the bottom of the plate, in order to provide additional ventilation for the material which is to be treated. In order to prevent an undesired outlet of the material through these openings, when the suction draught is not switched on, it is suitable to arrange around the plate an annular channel which surrounds the row of holes at such a height that the material which passes through the holes cannot overflow. Then, when the suction ventilator is switched on, the material located in the annular channel is sucked back into the mixing plate.

In a further advantageous development of the invention, rods, which are fixed stationarily, or which rotate contrary to the direction of rotation of the tool system, are arranged around the rotating tool system, on a ring or between two rings. Thereby the mixingand grindingeffect is improved in advantageous manner. In particular, without using too-high rotation speeds, it is nevertheless possible to produce satisfac' tory relative speeds between the particles which are to be pulvierized, and the rebound rods. It is particularly favorable for the rods to be positioned inclinedly in relation to one another, so that a shearing effect is produced, due to the relative movement.

Furthermore, according to the invention, in cases where poisonous or corrosive substances are being processed, it is particularly advantageous if the plates are arranged between the bottom of the mix material container and a covering element which is secured to the plates and rotates therewith. In this case it is particularly favorable if the rotating covering element forms the tool carrier for the plates. It is also suitable for the plates to penetrate through the rotating tool carrier and, on the side facing away from the bottom of the container, for a ring to be secured to the plates as a covering element. Furthermore, in order to effect with the least possible danger the infeed of acids or other poisonous liquids, the shaft of the tool system may be constructed as a hollow shaft through which the infeed tube is guided.

The machine according to the invention can be used also for the granulating or pelletizing of fusible masses, such as mixed fertilizers and complex fertilizers. If in such cases an extraction of the moisture is necessary, this is effected by introducing hot air; or first of all, drying is carried out by means of hot air, and then cooling is effected with cold air. If the high rotation speed mixing tool system according to the invention is built into a counterflow mixer (ribbon blender) or a centrifugal mixer, then it is possible to prepare, in such a machine, non-drip stifi' clay pastes with about 40 percent water content, for high grade fire resistant products. The same applies with regard to other plastic or liquid masses, such as paste paints or colored chalk mixtures. Finally, the machine according to the invention also may be used for chemical treatments; for example, in the manufacture of synthetic fertilizers, it is also possible to introduce ammonia through the tube, instead of air, in order to effect an ammoniation of the fertilizer. Of course, mist or vapor (e.g., of solvents) can also be blown in with the air, if this is desired, for example, during the mixing of synthetic fertilizers.

Further advantages, features and application possibilities of the present invention will be apparent from the ensuing description, with reference to the drawings. These show:

FIG. 1 a partial side view of a mixer according to the invention, with a rotating tube;

FIG. 2 another embodiment of the mixing tool according to FIG. 1;

FIG. 3 a plan view of the embodiment according to FIG. 1',

FIG. 4 a mixer which operates using centrifugal force;

FIG. 5 another embodiment of the mixing tool according to FIG. 1;

FIG. 6 a further embodiment of the mixer according to the invention in part-sectional side view;

FIG. 7 a preferred embodiment of the mixing tool, shown on a larger scale;

FIG. 8 a mixing tool, similar to the embodiment of FIG. 2 but in which an additional circle of rods is arranged around the mixing tool, on the outside thereof;

FIG. 9 another embodiment of the invention, in which the rods or plates project downwardly into the interior of the container; and

FIG. I a further embodiment of the invention, in which a ring is arranged on top, on the rods or plates, to form a covering element.

FIG. I shows, only diagrammatically, a mixer according to the invention, since plate-type mixers of the type illustrated in FIG. I are sufficiently well known to the expert, so that there is no need to illustrate constructional details such as the drive, the control means, the central discharge opening, the mounting of the plate, frame etc. The rotary mix material container 1 comprises a base wall 2 with a central discharge opening 4 and with a cylindrical peripheral wall 3. The mixing tool system 5 which is accommodated in the mix material container I is secured on a rotary shaft 6. A component part of the mixing tool system 5 is a disc-shaped rotary element 7 which is arranged at the free end of the rotary shaft 6. Rods 8 are arranged on the outer periphery of the rotary element 7. The rods 8 may be secured on the rotary element 7 in various ways, for example by means of screwing, keying, welding, etc., so the mode of their securing is not illustrated. The filling height of the mixing material inside the mixing material container is indicated diagrammatically, and the arrows which have been drawn in symbolize the suction and pumping effect of the mixing tool system according to the invention. FIG. l shows, below the disc, short prolongations 9 of the rods 8, which serve for keeping free the space below the rotary element 7, so that no friction occurs between the material to be treated, and the lower side of the rotary element 7. This is of importance for the invention in so far as the life of the tool system is thereby prolonged. A drive I0 sets the mixing tool system into rotation. As FIG. 5 shows, preferably also the rods 8 may be slightly inclined in the direction of the rotary shaft 5. This does not influence the mode of working of the mixing tool system but it increases the life of the rods 8 considerably, since the wear on the rods 8, extending outwards from the rotation axis, over a considerable period of time, cannot exert any adverse influence on the movement of the mix material which is aimed at. This embodiment will be preferred when mix material which causes considerable wear and tear has to be treated.

FIGv 2 shows another embodiment of the mixing tool system according to FIG. 1 which, as was already mentioned, is particularly suitable for materials which are capable of flowing in the dry and wet state. For reasons of clarity, the parts which are the same, are provided with the same reference symbols. The embodiment according to FIG. 2 is likewise secured to the free end of the rotary shaft 6. The apparatus shown here comprises an annular rotary element 11 and a disc-shaped rotary element l2. Rods 8 are let into the rotating elements It and I2, and hold the rotating elements at a certain desired distance apart from one another. The rods 8 are arranged, on a circular arc concentric to the rotary shaft 6, in the rotary elements I] and 12. The rotary shaft 6 is surrounded by antiwear plates 13 which are secured on the rotary shaft 6 by means of screws. By this means it is possible for the anti-wear plates 13 (which surround the rotary shaft 6 in the form of semi-cylindrical plates or, in larger number are assembled together to form a hollow cylinder) to be removed individually in the event of damage, or when they are worn out and replaced by new ones. The anti-wear plates 13 also may be of planar construction and may be assembled together to form a square. On the shaft 6 and/or or a rotating shaft is welded a flange 14 which carries the rotary element 12. The embodiment described above permits exchanging the anti-wear protection means and the rotary disc independently of one another. Furthermore, it is also possible to protect the surface of the carrying flange 14 by means of an anti-wear ring (not shown). Due to the abovementioned measures, the time spent on maintenance is considerably reduced. The flow or streaming of the mix material which can be achieved by means of the embodiment described in FIG. 2 is indicated again by arrows. The mix material is drawn in through the free annular space between rotary shah 6 and inner periphery of the rotary element l1, and the upper side of the disc-shaped rotary element imparts to the mix material a radially directed acceleration, so that it impacts upon the rods 8, as has already been described. In FIG. 2, furthermore, there is shown a fixedly arranged supply tube or conveying tube 40, which opens into the drawing-in area of the rods 8. Gas, liquid, or another material can be brought from above, in the direction of the arrow, into the suction area of the centrifuge formed by the tool system 5. The tube 40, for example, is connected to the water mains.

As is indicated in FIG. 3, preferably radial ribs 14' are arranged on the disc 7 and/or 12, in order to accelerate the centrifugal effect upon the material falling thereon.

FIG. 3 shows a mixer which has a tool system which carries mixing blades and which optionally possesses a mixing tool system 5 constructed in accordance with FIG. 1 or 2. The tool system 15, which carries mixing blades, consists substantially of a star-shaped mixer 16 with four arms 17 which carry, at their free ends, rods 18 which extend vertically in relation to the bottom wall 2, and which are provided, at their which face towards the bottom wall 2, with mixing blades l9. Instead of the mixing blades 19 it is also possible to provide knife-like tools in accordance with German Pat. Specification No. 724,073. Generally, all four arms 17 of knife carriers of this type will have knives 44.

The central discharge opening 4 is indicated in FIG. 3 in dash-dot lines, and it can be seen that the mixing blades I9 travel over this opening which contributes to the rapid empty ing of the apparatus. Preferably, the mixing blades 19 are secured to the rods 18, and/or the latter in their turn are secured adjustably to the arms 17, so that the direction of working of the blades is variable. For example, two blades may be so adjusted that they induce an optimum emptying effect, whereas the two remaining blades are so adjustable that they exert a radial conveying effect. Furthermore the possibility exists of providing the blades 19 arranged successively in dil ferent height adjustments. In the case of high powered machines, even two, three or four centrifuges may be assembled therein. Large machines are also equipped with two slowly rotating tool systems and two centrifuges. The slowly rotating tool systems may be equipped not only with mixing blades, but also as is described above with knife-like tools 44, in cases where, for example, fine friable pressed masses are intended to be produced, or where the production of granulates is desired. A further embodiment contains three high rotation speed mixing tool systems, and only one slowly rotating system, which substantially has the task of discharging the material. As soon as the machine is set in action for con tinuous operation, there is no need to use the slowly rotating system. It is therefore possible to operate with four centrifuges and/or high rotation speed mixing tool systems. Due to the aforementioned combination possibilities of the tool systems, the throughput of a machine may be increased so that it is doubled or multiplied.

FIG. 4 shows a further embodiment of the mixer in accordance with the invention. The mixer comprises a mixingmaterial container 1 rotatable about an axis which forms an angle with a horizontal plane. It is a special feature of this apparatus that the mix material container 1 is adapted to be driven at a rotation speed such that the centrifugal force which acts upon the particles of mix material is greater than their specific weight. In practice, in this apparatus, the centrifugal force is used as a magnet which attracts all the materials and which holds the mix material pressed against the peripheral wall 3 until the mix material impacts upon a deflecting device 20 which withdraws it from the action of the centrifugal force and drives it, in the form of a stream along a chord through the mix material container 1, until, at the opposite side, it meets the cylindrical peripheral wall again. Thereby an intensive mixing is achieved. The drive of this installation can be effected through known means, so that no explanation thereof is given here. As FIG. 3 shows a mixing tool system 5 is provided, which was already described in connection with FIG. 2. The mixing tool system 5 which is shown, also may be replaced by the embodiment in accordance with FIG. I. The shaft 6 of the mixing tool system 5 projects through the open side of the mix material container 1, into the device, and is driven through a drive 10. As was already mentioned, the direction of rotation of the mixing tool system 5 depends upon the position of the mixing tool 5 in relation to the chord like path of movement of the mix material. Generally, the mixing tool system 5 always rotates in such manner that the rods 8 move in a direction opposite to the direction of movement of the stream of mix material. Thereby a very intensive energy input is ensured. Furthermore, the rotary shaft 6 of the tool system 5 may be inclined in relation to the rotation axis of the mix material container. This mixer also may have, additionally, a mixing tool system which is described in connection with FIG. 3 and which is suitable with large types of machine.

As is the case in the other embodiments described above, the rotary mix material container 1 in FIG. 6 has a bottom or base, with a central discharge opening 4, and a cylindrical peripheral wall 3. The mixing tool 5 is secured on a rotary shaft 6. The actual mixing tool consists of the disc-shaped rotary element 7, on whose outer periphery are secured radially directed upwardly tapering trapezium-shaped plates 28. In the development of the plates, there may be provided an inner part, which is placed against the outer part of the plate, for purposes of reinforcing the plate against the high rebound stresses which occur in the tools which rotate at high rotation speed. In their upper part, which is most strongly impacted upon, the plates 28 have a coating 29, consisting of highly wear-resistant material.

The rotary shaft 6 of the tool is surrounded by a coaxial tube 30 which is arranged fixedly in the dustproof casing. The drive of the rotary mix material container 1 is effected in a manner known per se, by means of friction wheel, drive belt, or toothed wheel. The rotary shaft 6 is driven in the same direction as, or in the opposite direction to, the mix material container 1, by a separate motor (not shown), at a rotation speed substantially higher than that of the mixing plate. The upper side of the container I is covered by a fixed casing 31 which has an aperture for the rotary shaft 6 and the mounting of the tube 30, and which carries, via a second aperture, a discharge pipe 33 which is connected to the suction side of a blower (not shown). The discharge pipe 33 should be located as near as possible to the working area of the centrifuge, and is suitably provided with a height adjustable underpart which dips into the casing, in order that the suspension flow created by the centrifuge 5 can be sucked away with the greatest possible particle loading. The sealing of the tube 30 in relation to the casing 31 offers no difficulties, since low pressure prevails inside the mixing container space.

If the mixing machine with the tool according to the invention is intended to serve for cooling and/or drying of the material, it may be suitable to provide the container wall according to FIG. 6 in its underpart, with round or slot-shaped holes 38 through which additional air is sucked into the material to be treated, by means of the suction draught blower. When the suction draught is switched off, a collecting channel 39, which surrounds the row of holes, ensures that discharged material cannot overflow and is sucked back into the container when the suction draught is switched on again.

A preferred embodiment of the discharge tube 30 is shown in FIG. 7, applied to an inclinedly positioned mixing container with supercritical rotation speed. Here the tube 30 is arranged rotatably and is not led out of the container 1, but on the contrary, it ends, at the top, inside the mix material container. It is secured to the plates 28 by means of an annular disc 32, and its upper edge is reinforced by means of an outer annular flange 34. Spaced at a slight distance above the annular flange is located a truncated cone 35, approximately at the level of the tool hub 36. On the upper part of the truncated code 35 is connected an inlet pipe 37 which passes through the dustproof casing 31. In this embodiment, no sealing is necessary between casing inlet pipe, because both are arranged fixedly. The presence of a slight gap between the rotary tube 30 or the annular flange 34 and the fixedly arranged truncated cone 35 does no harm, because it is of no importance if, in addition to the quantity of gas sucked in through the pipe 37, a small additional quantity of gas also is drawn in through this gap, into the rotating tube 30. In this embodiment, the rotary element 7 is again provided with cams 9, such as were already mentioned in connection with FIG. 1 and 5.

With a machine equipped in accordance with the invention, it is also possible to achieve very good treatment effects, and in comparison to edge mill machines previously used, it is possible to increase the levelling height and therefore the useful filling, threefold or sixfold, while retaining the same diameter of the vessel. The treatment effect is dependent upon the energy introduced per time unit into the material to be treated; for example, approximately ID to 20 kWh of energy can be introduced into the machine per kg of fill material.

FIG. 8, similarly to FIG. 2, shows the right-hand half of the mix material container 1, with the bottom or base 2 and the cylindrical peripheral wall 3. Again the centrifuge 5 is illustrated diagrammatically, with the rotary shaft 6 and with the flange 14 which is welded thereon and which carries the rotary element 12 and therefore also the rods 8 and the upper rotary element, i.e., the ring II. Mounted in the hollow shaft 6 of the tool is a shaft 44, with a separate drive (not shown); the shaft has at its lower end a circular disc 42, with a ring of rods 43 located closely adjacent to the circle of the rods 8-, the upper ends of the ring of rods 43 are held in the ring 41. It is suitable for the

tool

41, 42, 43 to be driven in the direction opposite to the direction of the rods 8, so that there results an additional pulverizing effect, due to the addition of the two opposite directions of rotation.

FIG. 9 shows an embodiment of a centrifuge which is is suitable to use for the treatment of poisonous substances, or for the mixing-in thereof. In this case, the rods or plates 8 are attached on the underside of the rotating element 7 and their ends are directed towards the bottom 2 of the mix material container 1. Consequently, the disc 7 acts simultaneously as a covering element, in order to prevent the centrifuged substances splashing upwardly. It is suitable for the shaft 6 to be of hollow construction, so that, if desired, air can be sucked in through its central bore 45, or treatment gas or liquids can be introduced therethrough, for intimate mixing with the mix material in the working area of the blades 8.

FIG. 10 shows another embodiment of the centrifuge 5 used in FIG. 1; the rods or plates 8, in this case, are held in slots of the rotary element 7, in such manner that they penetrate the rotary element from both sides. Suitably, they are held at one end, in a reinforcing ring 41, and this tool is particularly suitable for use in the case of an inclinedly positioned mix material container, approximately in accordance with FIG. 4 or 7. If desired, the ring 41 also may serve a purpose similar to that of the ring 32 in FIG. 7 namely the holding or mounting of a rotatable guide tube 30.

We claim:

1. A mixing machine comprising a container mounted for rotation, a mixing device mounted on a shaft having an axis of rotation spaced from the axis of rotation of said container, means for rotating said mixing device about its shaft, said mixing device having a flat, rotary element carried on said shaft and mixing elements carried by said flat rotary element, said mixing elements being in the form of longitudinally extending members projecting generally upwardly from said flat rotary element at circumferentially spaced locations disposed radially outwardly of said shaft, said flat rotary element and said mixing elements being disposed below the level of the material which is being mixed in the container, whereby rotation of said mixing device causes the material being mixed to flow generally axially adjacent to said shaft towards said flat rotary element and thence radially outwardly past said mixing element to provide a pumping effect on said material.

2. A mixing machine according to claim 1 wherein said mixing elements are disposed generally parallel to the axis of said shaft.

3. A mixing machine according to claim 1 wherein said mixing elements are disposed at an acute angle relative to the axis of said shafi.

4. A mixing machine according to claim 1 wherein said rotary element is circular and said mixing elements are secured to said rotary element at circumferentially spaced locations on a circle which is concentric to the axis of said shaft.

5. A mixing machine according to claim 1 wherein said mixing device further comprises a second generally flat rotary element axially spaced from the first mentioned flat rotary element, said rotary elements being connected to one another by said mixing elements, said second rotary element having a central opening through which said shaft passes with an annular space being provided between said shaft and the edges defining said central opening.

6. A mixing machine according to claim I further comprising a second mixing device in said container mounted for rotation about an axis spaced from the axis of rotation of said con tainer, said second mixing device carrying mixing blades which pass over a discharge opening in the bottom of said container.

7. A mixing machine according to claim 1 wherein the axis of rotation of said container is disposed at an acute angle relative to a horizontal plane, said container being driven at a rotational speed which imparts to the constituents of the material being mixed a centrifugal force greater than the specific weight of said material, a deflecting means mounted in said container and operable to deflect the material as the latter is moved radially outwardly by centrifugal force and redirect said material radially inwardly such that a stream of mixed material is caused to flow along a chord through the container.

8. A mixing machine according to claim 1 wherein the axis of rotation of said container and the axis of rotation of said mixing device are disposed at an acute angle relative to one another.

9. A mixing machine according to claim I wherein a plurality of mixing devices are disposed in said container.

10. A mixing machine according to claim 1 further comprising a tube about the mixing device shaft and extending into an area centrally disposed relative to said mixing elements, said tube having a smaller outer diameter than the diametrical distance between said mixing elements.

1!. A mixing machine according to claim wherein said tube is in communication with a source of hot gas.

12. A mixing machine according to claim 10 wherein means are provided to rigidly connect said tube to said mixing device.

13. A mixing machine according to claim 10 wherein said tube is secured to said mixing elements.

14. A mixing machine according to claim 10 wherein cover means are provided on said container, and an inlet pipe carried by said cover is arranged to be in communication with said tube.

15. A mixing machine according to claim 1 further comprising a feed pipe which is fixed relative to the container and which extends into a drawing-in area located radially inwardly of said mixing elements.

16. A mixing machine according to claim 1 wherein said mixing elements comprise plates which are disposed perpendicular to the flat rotary element and which are radially dis relative to the axis of rotation of said mixing device.

7. A mixing device according to claim 16 wherein the radially inner edges of said plates taper upwardly and radially outwardly.

IS. A mixing machine according to claim 16 wherein the free end portions of said plates have a rectangular extension.

19. A mixing machine according to claim 1 wherein said mixing elements extend above the top of said flat rotary blade, and further comprising foreshortened mixing elements extending below said flat rotary plates.

20. A mixing machine according to claim 1 wherein means which includes a cover for said container is provided to make the container air-tight.

2]. A mixing machine according to claim 1 wherein the lower portion of the side wall of said container is provided with a plurality of air apertures.

22. A mixing machine according to claim 21 wherein means defining a trough are disposed on the outside of said container adjacent to said apertures whereby any material passing through said apertures is collected in said trough.

23. A mixing machine according to claim 1 further comprising a rotary ring element mounted on said mixing device and carrying rods disposed radially outwardly of said mixing elements.

24. A mixing machine according to claim 1 wherein said mixing elements extend above and below said flat rotary element, and a ring element fixed to those mixing elements which extend above said flat rotary element.

25. A mixing machine according to claim 1 comprising ribs mounted on said flat rotary element operable to effect accelerated rotation on the material impacting thereon.

26. A mixing machine comprising a container mounted for rotation, a mixing device mounted on a shaft having an axis of rotation spaced from the axis of rotation of said container. means for rotating said mixing device about its shaft, said mix ing device having a flat rotary element carried on said shaft and mixing elements carried by said flat rotary element. said mixing elements being mounted on the underside of the flat rotary element and extending towards the bottom of the container, whereby rotation of said mixing device causes the material being mixed to flow axially and thence radially outwardly past said mixing elements to provide a pumping effect on said material.

i i i t

Claims

3. A mixing machine according to claim 1 wherein said mixing elements are disposed at an acute angle relative to the axis of said shaft.

6. A mixing machine according to claim 1 further comprising a second mixing device in said container mounted for rotation about an axis spaced from the axis of rotation of said container, said second mixing device carrying mixing blades which pass over a discharge opening in the bottom of said container.

9. A mixing machine according to claim 1 wherein a plurality of mixing devices are disposed in said container.

11. A mixing machine according to claim 10 wherein said tube is in communication with a source of hot gas.

16. A mixing machine according to claim 1 wherein said mixing elements comprise plates which are disposed perpendicular to the flat rotary element and which are radially disposed relative to the axis of rotation of said mixing device.

17. A mixing device according to claim 16 wherein the radially inner edges of said plates taper upwardly and radially outwardly.

18. A mixing machine according to claim 16 wherein the free end portions of said plates have a rectangular extension.

21. A mixing machine according to claim 1 wherein the lower portion of the side wall of said container is provided with a plurality of air apertures.

26. A mixing machine comprising a container mounted for rotation, a mixing device mounted on a shaft having an axis of rotation spaced from the axis of rotation of said container, means for rotating said mixing device about its shaft, said mixing device having a flat rotary element carried on said shaft and mixing elements carried by said flat rotary element, said mixing elements being mounted on the underside of the flat rotary element and extending towards the bottom of the container, whereby rotation of said mixing device causes the material being mixed to flow axially and thence radially outwardly past said mixing elements to provide a pumping effect on said material.