EP0500561B1 - Process and device vor stirring and thermal treatment of solid particles - Google Patents

Abstract

PCT No. PCT/DE90/00800 Sec. 371 Date May 19, 1992 Sec. 102(e) Date May 19, 1992 PCT Filed Oct. 21, 1990 PCT Pub. No. WO91/06364 PCT Pub. Date May 16, 1991.A device for moving solid particles, especially one designed as cooling mixer, has a substantially horizontal jacketed tank (11), in which a shaft (14) is seated for rotation. The shaft (14) is equipped with mixing tools. Bulk material can be introduced into the tank (11) through a charging opening (23), and the processed material can be extracted from the tank (11) through a discharge opening (26). The product space of the tank (11) is equipped with partition walls which subdivide the product space into processing zones. The solid-particle mixer (10) is particularly well suited for quasi-continuous operation. Processing of the bulk material is carried out in the pile and product feeding toward the discharge opening (26) is effected in the state of a mechanically generated fluidized bed, or a product toroid.

Description

The invention relates to a device for mixing and thermal treatment of solid particles with a substantially horizontally arranged container, which is penetrated along its longitudinal axis with a shaft provided by a drive motor, with a loading and emptying opening arranged on the container, the container being transverse to the longitudinal axis is divided between the loading opening and the emptying opening by means of cutting disks with at least one through opening into at least three interconnected chambers and with in each chamber at least one tool arranged radially on the shaft, the tool being suitable for imparting a tangentially and / or axially directed movement impulse to the Pass on solid particles, and a method for mixing and thermal treatment of solid particles.

Such a device has become known from DE-A-11 12 968.

Devices for mixing solid particles with rotating tools, which have a horizontally arranged cylindrical container with a shaft coaxially guided in the container with mixing tools, are known as batch mixers and continuously operated mixers.
In batch operation, the machine used as a mixer, dryer, reactor or cooler is charged with the bulk goods or additives to be treated. Is the loading process completed, there follows a treatment process in which the bulk goods are mixed with one another, cooled, dried, heated, crushed or agglomerated. During this treatment, reactions can also take place that give rise to new products or release gases that are drawn off via suitable breeding stubs. When the treatment of the product is complete, it is discharged from the machine in an emptying process.

For batch mixers, to determine the time in which a solid mixture can be produced, the loading time of the bulk materials to be mixed, the emptying time of the bulk material mixture and the actual mixing time within which the bulk materials are mixed with one another and with one another by the rotating mixing tools. This results in longer mixing times in batch operation than in continuous operation. In continuous operation, there are no waiting times that arise in batch operation due to the loading and emptying of a mixer. In continuous operation, the bulk material streams to be processed are fed simultaneously and a bulk material stream, the finished mixture, is removed. This is also possible with bulk material flows that are to be thermally treated or cooled in continuous operation. In a continuously running cooling process, the hot solid bed enters the cooling mixer, while at the same time cooled bulk material is drawn off at the other end of the cooling mixer.

Difficulties arise in continuous operation to control the transport behavior of a bulk material flow to be cooled so that, for example, bulk material that has not already been cooled is mixed with still warm or hot bulk goods. If backmixing occurs, there is a mixing temperature in the bulk material of the product interior that is always higher than the desired final temperature. Added to this is the fact that in the case of backmixing, already cooled particle collectives remain in the product interior longer than permitted. These particle collectives can be destroyed by the mixing tools due to a longer mechanical treatment. Therefore, when cooling a bulk material flow in continuous operation, the lowest possible backmixing of treated with untreated bulk material should always be aimed for. Controlling the cooling process in the known devices in this way is often not possible because fixed process parameters often conflict with such an operating mode and the temperature of a bulk material cannot be reduced in an arbitrarily short time due to heat being given off to a coolant.

wobei m als Masse der Partikel, r als Radius der Trommel, g als Erdbeschleunigung mit der Gleichung g = r·n_c²·4π², ω als Winkelgeschwindigkeit der Mischwerkzeuge und n_c als kritische Drehzahl definiert ist.The known mixers are generally operated at a fixed, apparatus-specific centrifugal speed which has been previously coordinated with the processing process. To maintain the kinematic similarity, the dimensionless parameter Fr (Froude number) is introduced instead of the centrifugal speed n. Fr is a measure of the ratio of centrifugal and gravitational acceleration independent of the drum diameter. The Froude number can be represented by the following equation: $$\text{Fr =}\frac{\text{mx ω² xr}}{\text{mxg}}$$

where m is the mass of the particles, r is the radius of the drum, g is defined as gravitational acceleration with the equation g = r · n _c ² · 4π², ω as the angular velocity of the mixing tools and n _c as the critical speed.

With the continuous working solid mixer known from the dissertation from 1984 with the title "Investigations of the movement of bulk goods with the continuous mixing of solids" (Faculty of Process Engineering of the University of Stuttgart), the mean residence time of the bulk goods in the solid mixer can be controlled via the bulk material mass stored in the product interior and the bulk material flow. The product interior of this solid mixer extends from the frontal boundary surface to a weir, which is provided in the cylindrical drum and is installed directly in front of the product discharge nozzle. The bulk material mass stored in front of the weir towards the product inlet nozzle is subject to strong backmixing at centrifugal speeds of Fr ≧ 4, as shown, for example, by the diagrams of the axial dispersion coefficient D as a function of the Froude number Fr on page 108 of this work. However, if a bulk material flow is to be continuously cooled, this is disadvantageous, as already explained.

The mixer known from DE-A-11 12 968 has, as shown in FIG. 2 of the drawing, a jacket which is not explained in more detail in the description. In order to ensure effective thermal treatment, it is not only necessary to provide a container jacket, but it is also imperative to design it in such a way that effective cooling or heating of the product flowing in the container is possible. Furthermore, an uncontrolled product flow is possible through the openings of the cutting discs located on the bottom.

The invention is therefore based on the object of developing and operating a solid mixer of the type mentioned at the outset such that the thermal treatment of the bulk material flow can be better controlled over the entire length of the solid mixer.

This object is achieved according to the invention by the device according to claim 2 and the procedure according to claim 1.

The solid mixer according to the invention thus has the essential advantage that it can be thermally cooled or heated in cross flow. The known heating and cooling mixers in a horizontal arrangement can only be operated in cocurrent and / or countercurrent because the structurally known jacket structure allows fluid flow only along the product stream. Will along the Invention according to the solid mixer, a central supply and discharge line connected to the casing, the fluid cooling or heating the product can be guided across the circumference of the product flow around the container. Thermally, this has the advantages that a maximum temperature difference can be achieved at a constant fluid inlet temperature both at the product inlet and at the product outlet.

Furthermore, the solids mixer according to the invention has the advantage that it divides the product interior, the space seen in the axial direction from the face on the entry side to a cutting disc in front of a product discharge nozzle, into at least two processing zones, in which the bulk material flow, almost independently of the other processing zone, can be treated.

In so-called bulk mixing, no solid particles are torn out of the material bed. The bulk material remains completely in the respective processing zone, provided that the through openings are above the product level. If, for example, a bulk material is to be continuously cooled in the solid mixer according to the invention, no solid particles can pass from the one processing zone into the other processing zone during cooling in the pile. There can therefore be no backmixing between the processing zones. The axial dispersion can only take place within the respective processing zone.

The product interior can be divided into several processing zones as required, each of which is separated from the other by cutting discs. Now the centrifugal speed is increased to the extent that the tools in the product interior generate mechanically generated fluidized bed, swarms of particles can enter the respective adjacent processing zones through the through openings. In this way, the processing zone immediately below the loading opening can be emptied so that it can be filled with a new batch. The processing zone below the loading opening can also be loaded with new product if the bulk material from the previous batch is still being treated in the adjacent processing zone.

The solid mixer according to the invention can be operated particularly advantageously quasi-continuously due to the special design of its product interior. A quasi-continuous mode of operation is to be understood here to mean that the bulk material or batches flow into the product interior in batches and leave the product interior as a continuous product stream. The definition also includes the reverse mode of operation, that the solid mixer according to the invention is fed continuously and the treated bulk material is discharged from the solid mixer in batches.

If the solid mixer according to the invention is operated as a batch mixer or batch cooler in the range of Fr <1, it is always ensured that a particle exchange along the shaft, i. H. cross-mixing is only possible within the processing zones delimited by cutting discs. This enables products of different treatment levels to be effectively separated from one another even in batch operation.

The solid mixer according to the invention is not only a multi-chamber operation in batch mixers or continuously or quasi-continuously operated mixers in a horizontally arranged drum, but an operating mode that largely separates the treatment of the bulk material from its axial transport towards the outlet. The bulk material is treated in the pile and transported in the mechanically generated fluidized bed or in the bulk material ring. Linking two operating modes in one machine is therefore an essential idea of the invention.

The rotating tools transport the bulk material away from the loading opening in the direction of the discharge opening. Due to centrifugal machine speeds, which create a mechanical fluidized bed or a product ring of the bulk material in the product interior, the transport component is reinforced in the direction of the product discharge. The bulk material from the processing zones can thus be quickly emptied towards the product discharge. If a product stream is to be cooled, this can be achieved by effective mixing in the material bed of the respective processing zone and the axial transport into the adjacent processing zone for product discharge takes place in that the bulk material is fluidized, ie. H. A mechanical fluidized bed or a product ring is temporarily generated in the product interior.

With the container encased according to the invention, it is possible to operate the solid mixer as a cooling mixer or to use it as a solid mixer for heat treatment of bulk materials with an elevated temperature medium. Cooled and / or heated water, steam or thermal oil can flow through the casing as a carrier medium. Cryogenic fluids can also be used.

The container designed according to the invention has elements for supplying and / or removing heat on or in the container wall which surround the container in the circumferential direction to more than 180 °, but less than 360 °. This ensures that the entire bulk material mass stored in the product interior rests against inner wall sections of the container which are actively cooled or heated.

In the device according to the invention, the peripheral section free of the elements lies in the upper region of the container.

This has the advantage that the elements are attached to the areas in the container in which large heat transfer coefficients are achieved. As can be seen from the publication "Local heat transfer coefficients in a ploughshare mixer", Process Engineering 76, No. 12, the heat transfer coefficients measured in the lower tank area differ from the heat transfer coefficients in the upper tank area by a factor of four.

Another advantage of the method according to the invention for mixing and thermal treatment of solid particles in multi-chamber operation is that the method works quasi-continuously. The product interior stores such a large bulk material mass that bulk material introduced batchwise into the product interior does not affect the continuous outflow of the bulk material. The processing zones are separated from each other by cutting discs, so that it is possible to load the first processing zone, which is located directly below the loading opening of a solid mixer according to the invention, in batches and the treated bulk material is continuously withdrawn from the last processing zone of the product interior via the product discharge nozzle.
If the product treatment takes place in the pile and the product flow for discharge in the mechanically generated fluidized bed or in the product ring, the bulk material can be remixed within of the product interior and its transport to the product discharge nozzle are controlled as best as possible.

In a further development of the invention, the sections of the casing allow heat to be supplied and / or removed independently of one another.

This has the advantage that the bulk material in the product interior along the container can be cooled or heated to a greater or lesser extent depending on the section. The use of a solid mixer of this type is more diverse and can be better adapted to predetermined process steps.

If the sheathing consists of half-tubes welded onto the outer wall of the container, which are connected to a central feed line and discharge line, the flow guidance for liquid carrier media is specified. The flow resistances in the casing are defined. If the half-tubes are individual half-tubes which are welded to the container jacket in a largely semicircular shape, the rigidity of the container is improved and the container can be produced with a reduced container wall thickness.

If an opening flap is provided in the upper region of the container almost over the entire length of the container, the solid mixer according to the invention can be cleaned well and quickly if required. An exchange of tools or work on cutter head systems are made easier. The opening flap itself is not covered with half tubes. This enables simple and inexpensive manufacture of the opening flap. The dead weight is lower, so that the opening flap can also be easily pivoted in manual mode.

In a further embodiment of the invention, the cutting discs can be cooled and / or heated.

This has the advantage that additional cooling and / or heating surfaces are created in the product interior. The bulk material is pressed due to the bulk material flow itself and by means of the rotating tools against the cooled or heated surfaces of the cutting discs. The heat transfer is particularly good at these points. If the shaft and tools are still cooled or heated, these internals support and improve the cooling or heating process.

In a preferred embodiment of the invention, the drive motor is a pole-changing motor or a motor that is infinitely variable in speed.

This has the advantage that the bulk material treatment can take place in the respective processing zones in the pile. The energy introduced into the bulk material via the rotating tools is low, so that the bulk material is only slightly heated during a cooling process. In addition, the bulk material to be treated is mixed very gently. If the bulk material is to be transported from one processing zone to another processing zone, the speed of the centrifugal unit is increased briefly. In the fluidized state, the bulk material can overcome the cutting discs through the through openings. The tools are designed and placed on the shaft in such a way that they support a transport of the bulk material in the fluidized state in the direction of the product discharge.

The solid mixer according to the invention thus meets all of the extended requirements that are placed in particular on devices for cooling bulk materials. It can be operated in batches, continuously or quasi-continuously. Along the solid mixer, container sections can be operated independently of one another with media of different temperatures. Large specific cooling capacities can be achieved through the special mode of operation of the solids mixer, cooling in the pile, transport of the bulk material in the fluidized state. The cooling process is supported by a cooled shaft, cooled tools and cooled cutting discs. The through openings are arranged in the product interior in such a way that short-circuit flows of the bulk material are prevented and an axial dispersion takes place essentially only in the respective processing zone.

Further advantages result from the description and the attached drawing. Likewise, the features mentioned above and those listed further can be used according to the invention individually or in any combination with one another. The mentioned embodiments are not to be understood as an exhaustive list, but rather have an exemplary character.

Fig. 1

einen erfindungsgemäßen Feststoffmischer mit Halbrohren als Doppelmantel und einer sich nahezu über die gesamte Länge des Feststoffmischers erstreckenden Öffnungsklappe;

Fig. 2

eine Seitenansicht eines erfindungsgemäßen Feststoffmischers mit verschwenkter Öffnungsklappe und einem Messerkopfsystem;

Fig. 3

ein Ausführungsbeispiel eines Produktinnenraums eines erfindungsgemäßen Feststoffmischers mit symbolhaft dargestellten Mischelementen;

Fig. 4a

einen Schnitt IVa - IVa der Fig. 1;

Fig. 4b

einen Schnitt IVb - IVb der Fig. 1;

Fig. 4c

einen Schnitt IVc - IVc der Fig. 1;

Fig. 5

eine schematische Darstellung zur Produktbewegung im Innenraum des erfindungsgemäßen Feststoffmischers bei verschiedenen Schleuderwerksdrehzahlen;

Fig. 6

einen in bekannter Weise kontinuierlich arbeitenden Feststoffmischer;

Fig. 7a

einen nach der Erfindung arbeitenden Feststoffmischer im quasi-kontinuierlichen Betrieb;

Fig. 7b

ein weiteres Ausführungsbeispiel eines quasi-kontinuierlich arbeitenden Feststoffmischers.

The invention is illustrated in the drawing and is explained in more detail with reference to exemplary embodiments in the drawing. Show it:

Fig. 1

a solid mixer according to the invention with half pipes as a double jacket and one opening flap extending almost the entire length of the solids mixer;

Fig. 2

a side view of a solid mixer according to the invention with pivoted opening flap and a cutter head system;

Fig. 3

an embodiment of a product interior of a solid mixer according to the invention with symbolically represented mixing elements;

Fig. 4a

a section IVa - IVa of Fig. 1;

Fig. 4b

a section IVb - IVb of Fig. 1;

Fig. 4c

a section IVc - IVc of Fig. 1;

Fig. 5

a schematic representation of the product movement in the interior of the solid mixer according to the invention at different centrifugal speeds;

Fig. 6

a solid mixer operating continuously in a known manner;

Fig. 7a

a solid mixer working according to the invention in quasi-continuous operation;

Fig. 7b

a further embodiment of a quasi-continuous solid mixer.

The individual figures of the drawing show the subject according to the invention in a highly schematic manner and are not to be understood to scale. The objects of the individual figures are shown partially enlarged so that their structure can be shown better.

1 shows, at 10, a solids mixer which can mix bulk goods in batch operation, in continuous or quasi-continuous operation and treat them thermally. The solids mixer 10 is composed of a container 11, a horizontally arranged cylindrical drum, and head pieces 12, 13 which are attached to the front sides of the container 11. The head pieces 12, 13 can be welded or screwed to the end faces of the container 11. The head pieces 12, 13 have an opening which is arranged circularly and coaxially to the longitudinal axis of the container 11. A shaft 14 is guided through the opening in the head piece 12, 13 and is rotatably held in bearings 15, 16 connected to the head pieces 12, 13. The free end of the shaft 14, a shaft journal 17, projects beyond the bearing 16. The shaft journal 17 can be connected to a motor via a suitable gear. The unit comprising the motor and gearbox serves as the drive unit for the shaft 14. Mixing elements are arranged on the shaft 14 in the container interior, which can perform a rotary movement together with the shaft.

The solids mixer 10 can be fastened to the foundations or frame structures by means of supports 21, 22. In FIG. 1, pointing obliquely to the rear, a loading opening 23 is arranged on the container 11, which is designed as a loading nozzle 24 with a flange. Bulk material to be processed can flow into the container 11 in the direction of arrow 25 via the feed nozzle 24. The loading opening 23 can be connected to pipe and loading systems via the flange on the loading nozzle 24. In the lower region of the container 11, an emptying opening 26 is provided, which is designed as an emptying nozzle 27 with a suitable flange. Bulk material treated in the solid mixer 10 can be discharged via the emptying nozzle 27 in the direction of arrow 28.

A ventilation port 31 is provided as a further opening on the container 11, via which a pressure equalization in the interior of the container can be achieved or via which vapors or gas flows can be drawn off. At the bottom of the container, opposite the feed nozzle 24, a further nozzle 32 is attached, which is closed with a blind flange 33. About the nozzle 32, the bulk material in the container can be emptied or the bulk material flow can be controlled starting from the loading in the direction of arrow 25 so that the bulk material immediately after it has flowed into the container 11, the container 11 leaves the nozzle 32 . This makes sense if, for example, the solid mixer 10 is integrated in a system and the processing step of the bulk material possible by the solid mixer 10 is not necessary or if a fault occurs in the solid mixer 10. Between the emptying nozzle 27 and the nozzle 32, further nozzles can be attached to the solids mixer 10 through which individual processing zones can be emptied directly.

In Fig. 1, an opening flap 35 is provided along the top of the solid mixer 10. The opening flap 35 can be manually operated and / or also opened or closed automatically with the aid of aids. Sight glasses 36, 37, 38 are fastened in the opening flap 35, via which the bulk material flow in the container 11 can be visually checked.

Half pipes 40 are welded onto the outer wall of the container and are connected to a supply line 41, 42, 43 in such a way that the supply line 41, 42, 43 can supply the half pipes 40 connected to it with a cooling / heating medium. The connection to a corresponding cooling / heating medium supply device takes place via a flange connection 41 ', 42', 43 '. The feed lines 41, 42, 43 are separated from one another, so that the half pipes 40 connected to the respective feed line 41, 42, 43 can be operated separately with media of different temperatures. The half-pipes 40 end on the rear side of the solid-state mixer 10, which cannot be seen in the figure, by opening into a discharge line, which is designed to be comparable to the feed line 41, 42, 43. The half-tubes 40 surround the container 11 in the circumferential direction to more than 180 °, but less than 360 °.

Half-tubes 40 are also to be understood as half-tubes which are arranged in a circular arc on the container jacket and do not continuously guide the medium flowing through in a helical manner.

On the back of the solid mixer 10, the half-tubes 40 are drawn further up than on the front. This constructive design of the half-tubes 40 on the container 11 makes it possible that even a bulk material raised in the direction of rotation lies completely against the cooled surfaces of the container 11.

The container 11 has support rings 45, 46 on the outer wall of the container, which are also formed on the opening flap 35. The support rings 45, 46 stiffen the container 11, so that there is a constant rounding of the drum with a very narrow tolerance range over the length of the container 11. Half-tubes 40 attached in a circular arc improve the inherent rigidity of the container 11.

On the back of the solid mixer 10, temperature sensors 48, 49, 50 are guided through the container wall into the product interior. The temperature of the bulk material in the respective container section can be determined via the temperature sensors 48, 49, 50. Depending on requirements, fast rotating cutter head systems 51, 52 can be attached to the solid mixer 10, which in addition to the mixing of the solid particles by the tools on the shaft 14 can separate agglomerates or influence the grain size distribution of the bulk material to be processed.

2 shows the solids mixer 10 in a side view. The head piece 12 hides the horizontally lying drum, which is shown in the figure with broken lines. The Shaft journal 17 protrudes from the bearing 16, in which the shaft is rotatably mounted. The opening flap 35 is swung open and the charging nozzle 24 and the ventilation nozzle 31 are visible. The half pipes 40 with the feed line 41 and a discharge line 54 are shown on the outer wall of the container. About the nozzle 41 ', 54', the half pipes 40 can be connected to a coolant / heating medium supply device, not shown, or a drainage system. The feed and discharge lines 41, 54 can also be formed jointly on one long side of the solid mixer 10. The fluid guided in the feed and discharge line 41, 54 then crosses twice the product stream, in which it first flows around the container 11 transversely to the longitudinal axis and then again flows transversely to the longitudinal axis transversely of the container 11. Laterally in the lower area, the cutter head system 51, which has its own drive, is guided obliquely upward through the container wall.

2 shows a cutting disc 56 with a through opening 57. A bulk material entering the container interior through the feed nozzle 24 can only be conveyed through the passage opening 57 along the shaft. The product cooling or heating fluid is fed to the solid mixer 10 over the entire length via the nozzle 41 'and the feed line 41 and the fluid passed through the half pipes 40 across the product stream is withdrawn via the discharge line 54 and the nozzle 54'.

Fig. 3 shows a solid mixer 60 highly schematic in longitudinal section. A cylindrical, horizontally lying drum 61 receives a shaft 62 which is mounted in bearings 63, 64 on head pieces 65, 66 and is rotatably mounted. Bulk material can enter the product interior in the direction of the arrow 68 via a feed nozzle 67 flow in. The treated bulk material can flow out of the product interior in the direction of arrow 70 via an emptying nozzle 69. Solid blades 71 and half blades 72 are shown symbolically in the figure as tools which are connected in a rotationally fixed manner to the shaft 62. In the figure, the product interior is divided into a first processing zone 73, a second processing zone 74 and a third processing zone 75. The first processing zone 73 is axially delimited by the head piece 66 and a cutting disk 76. The cutting disc 76 has a through opening 77 through which the bulk material flowing in in the direction of arrow 68 can be conveyed from the first processing zone 73 into the second processing zone 74. The bulk material in the interior of the product is conveyed, on the one hand, by the bulk material flow itself and, on the other hand, by a movement component directed in the bulk material in the axial direction towards the emptying nozzle 69, which is generated by the rotating full blades 71 and half blades 72. The second processing zone 74 is delimited to the feed nozzle 67 by the cutting disc 76 and to the emptying nozzle 69 by a cutting disc 78. The cutting disc 78 has a through opening 79 which connects the second processing zone 74 to the third processing zone 75. The third processing zone 75 is delimited by the cutting wheel 78 and a cutting wheel 80. A through opening 81 of the cutting disc 80 connects the third processing zone 75 to the space which has the drainage spout 69. The space with the emptying nozzle 69 can be used as a further additional processing zone, if necessary, by suitable operation of closure elements on the emptying nozzle 69. The bulk material can flow out of the product interior via the discharge nozzle 69 in the direction of arrow 70. Will the shaft 62, together with the full blades 71 and the half blades 72 forms the centrifugal mechanism, rotated in the direction of arrow 82, the solid particles in the bulk material are mixed intensively with one another by the full blades 71 and the half blades 72 and at the same time due to the setting of the full blades 71 and the half blades 72 on the shaft 62 from the first processing zone 73 into the second processing zone 74 and also promoted into the third processing zone 75. The cutting disks 76, 78, 80 further have the effect that a short circuit can be prevented in a continuous or quasi-continuous mode of operation of the solids mixer 60. A short circuit is to be understood here as meaning that solid particles which enter the product interior through the feed nozzle 67 immediately afterwards exit the product interior via the emptying nozzle 69, without having the respective mean residence time in the first, second, third processing zones 73, 74.75 have lingered. The cutting discs 76, 78, 80 can have through openings 77, 79, 81 of different sizes. The size and position of the through openings 77, 79, 81 depends on the product; they must be matched to the respective bulk material parameters, such as bulk density, material density, grain size range, flow function. According to the position, the through openings 77, 79, 81 can be arranged both in the upper and in the lower drum area. The through openings 77, 79, 81 are usually offset in such a way that a direct product flow from the feed nozzle 67 to the discharge nozzle 69 can be ruled out.

Fig. 4a shows the container 11 of Fig. 1 in section IVa to IVa. The illustration of the opening flap has been omitted in the figure. Tools 86 are arranged in a rotationally fixed manner on a hollow shaft 85. The tools 86 are designed as ploughshare-like mixing tools. They have a leading tip 87 and from this outgoing, as work surfaces side cheeks 88, at least one of which is inclined to the direction 89 of the mixing tool in such a way that it encloses an obtuse angle with a plane transverse to the longitudinal axis which is laid through the longitudinal axis of the mixing tool. The obtuse angle at which the cheeks 88 of the mixing tools are inclined corresponds approximately to the inner fracture lines of the bulk material when a flat surface passes through the bulk material. A cooling or heating medium flows through the tools 86 as well as the hollow shaft 85. A first processing zone 90 is delimited towards the bulk material discharge by a cutting disk 91. The cutting disc 91 is provided with a through opening 92 which connects the first processing zone 90 to a second processing zone 93 located behind the cutting disc 91. The cooling or heating medium flows through half pipes 94. The cooling or heating medium enters the casing via a connector 95 and leaves the jacket system through a connector 96.

The cooling or heating medium is uniformly distributed over the individual half pipes 94 via a feed line 97. The cooling or heating medium, which has flowed through the individual half-tubes 94, is combined in a discharge line 98 and discharged centrally via the nozzle 96.

4b shows the section IVb to IVb from FIG. 1. A cutting disk 99 separates the second processing zone 93 from a third processing zone 100. The rotating tools 86 convey the bulk material from the second processing zone 93 through a through opening 101 into the third processing zone 100 Half-pipes 102, which are fed via a connector 103 and a feed line 104, can be supplied with a cooling or heating medium operated at a different temperature than the half-tubes 94, which are shown in Fig. 4a. The cooling or heating medium leaves the casing via a central discharge line 105 and a connector 106. The opening flap is not shown in the section of FIG. 4b.

FIG. 4c shows a section IVc to IVc of FIG. 1. A cutting disc 108 delimits the third processing zone 100 towards the product outlet. The processed bulk material flows through a through opening 109 in the cutting disc 108 into the room with an emptying nozzle. The tools 86 rotating in the third processing zone 100 convey the bulk material in the direction of the cutting disc 108 and lift it through the through opening 109. Half pipes 111, which form the casing of the drum section of the third processing zone 100, can in turn be operated at a temperature of the cooling or heating medium that differs from the temperatures at which the first processing stage 90 and the second processing stage 93 are operated.

The cutting discs 91, 99, 108 can also be cooled or heated. The bulk material conveyed from the product inlet to the product outlet is dammed up at the respective cutting discs 91, 99, 108. They produce a force that counteracts the axial direction of conveyance of the bulk material.

5a, 5b and 5c show the bulk material movement in the device according to the invention in a highly schematic manner. Depending on the Froude number, which is a measure of the ratio of centrifugal and gravitational acceleration, the movement behavior of the bulk material inside the product changes. When the centrifuge rotates slowly at first, the product turns in the direction of rotation raised. This is shown in Fig. 5a. Tools 112 rotate in the direction of arrow 113 and move the individual solid particles in the pile. This creates an angle of the free product surface which corresponds approximately to the angle of repose of the bulk material to be processed. When mixing in a pile, little energy is introduced into the bulk material via the tools. There is an intensive exchange of the solid particles towards the heated or cooled wall.

5b, solid particles are increasingly thrown out of the bulk material bed into the free mixing space when the tools 112 rotate in the direction of the arrow 113 with an increased number of Froudes. The bed is fluidized more and more. It is a matter of mixing solids in a mechanically generated fluidized bed. Due to the higher spin speed, more friction energy is generated and the bulk material is heated due to the intensive movement. In a cooling process with the device according to the invention, the rising bulk material temperature which arises due to the rapidly rotating tools 112 can be counteracted directly by cooled tools and cooled cutting disks.

In Fig. 5c, the centrifugal machine rotates at a centrifugal machine speed which causes a more or less closed product ring to be present in the interior of the product. The consistency of the product ring corresponds to a compacting fill. The frictional forces are high, the bulk material to be treated is heated up considerably.

In the device according to the invention, the bulk material movement states shown in FIGS. 5b and 5c only become set briefly and at intervals. Increased centrifugal machine speeds serve to transfer the cooled bulk material through the through openings into the next processing zone. The increased axial feed of the bulk material is achieved within a few seconds, so that in a subsequent longer time interval the cooling mixer can be operated at a centrifugal speed which results in a bulk material movement, as shown in FIG. 5a.

The device is provided with a pole-changing or steplessly adjustable drive so that the product states of FIGS. 5b and 5c can be set from time to time. The cooling process itself takes place on the basis of a bulk material movement that takes place in the pile, i.e. that is, the spinner is operated with a Froude number of Fr <1.

6 shows a solid mixer 150 which is operated as a continuously operating mixer. A drum 151 receives a shaft 152. The mixing elements are arranged on the shaft 152. Bulk material is fed into the product interior of the solid mixer 150 via a feed nozzle 153 and the treated bulk material is drawn off via an emptying nozzle 154. In the direction of the arrows 155, 156, which symbolically symbolize the continuous mass flow, the bulk materials flow into the solid mixer 150 and the treated bulk materials flow out again. Cutting discs divide the product interior into individual, independent processing zones. The bulk materials are mixed both radially and axially within the processing zones.

7a shows an exemplary embodiment of a quasi-continuously operating solid mixer 160, the drum 161 of which receives a shaft 162 and on which a loading nozzle 163 and an emptying nozzle 164 are arranged. Bulk material is introduced in batches into the product interior of the drum 161 in the direction of the arrows 165, 166 and the treated bulk material is continuously discharged in the direction of the arrow 167. The quasi-continuous mode of operation results in FIG. 7a from a batch-wise product entry and a continuous product discharge.

7b shows a further exemplary embodiment of a quasi-continuously operated solid mixer 170. In a drum 171, the bulk material flowing in via a feed nozzle 173 is processed by means of rotating mixing tools arranged on a shaft 172. The treated bulk material is discharged via an emptying nozzle 174. 8b, the solids mixer 170 is continuously charged in the direction of the arrow 175 and the product is discharged batchwise in the direction of the arrows 176, 177. The product interior of the solid mixer 170 can be divided into several processing zones. Via the operating mode of the centrifugal machine, the product flow in the product interior of the mixer 170 can be controlled in such a way that product from the first processing zone, which is arranged near the feed nozzle 173, is transferred to the second processing zone as quickly as possible. The other processing zones are also filled with product. Because the first processing zone is emptied faster than the subsequent processing zones, it can take up the continuous product flow in the direction of the arrow 175 without interference and a product jam or overfilling of the first processing zone is prevented.

The length-diameter ratio in the case of solid mixers operated continuously and quasi-continuously is usually greater than two and the position of the feed nozzle to the discharge nozzle is such that the distance between them is as large as possible.

Claims (7)

1. Method of mixing and thermally treating solid particles, wherein the solid particles are introduced, via a charge opening (23) into an input chamber of a tank (11) which is arranged in a horizontal manner;
   wherein, in order to treat and transport the product in the tank (11) which consists of at least three chambers being separated by partition walls (76, 78, 80; 91; 99; 108) which are disposed transversely to the longitudinal axis and comprise at least one passage opening (77, 79, 81; 92; 101; 109), the solid particles being movable by means of at least one tool (86) being provided in each chamber and disposed radially on a shaft (14; 62) running in the longitudinal direction and having a drive motor;
   wherein the tool (86) moves the solid particles in a tangential and/or axial direction;
   wherein the solid particles are discharged via a discharge opening (26) from an input chamber of the horizontally arranged tank (11);
   wherein the product treatment in the pile and the product transport within the tank (11) occurs in a fluid state of the bulk material;
   wherein either the bulk material to be treated is introduced in batches into the input chamber and is discharged from the discharge chamber in a continuous manner or the bulk material to be treated is introduced into the charge chamber in a continuous manner and is discharged from the discharge chamber in batches;
   wherein the solid particles are thermally treated by means of a jacket which surrounds the tank (11) over almost the entire length, by more than 180° but less than 360°, in the circumferential direction;
   and wherein the jacket is subdivided along the longitudinal axis of the tank (11) into one or several sections, wherein each section comprises a charge line (41, 42, 43; 97; 104) on one side and a discharge line (54; 98; 105) on the other side, which extend in the axial direction almost across the entire length of each section of the jacket and also terminate in the jacket along the entire length.
2. Device for mixing and thermally treating solid particles with a tank (11) which is arranged essentially horizontally and is penetrated along its longitudinal axis by a shaft (14; 62) provided with a drive motor, with a charge opening (23) and a discharge opening (26) provided on the tank (11), wherein the tank (11) is subdivided, transversely to the longitudinal axis, between the charge opening (23) and the discharge opening (26), by means of partition walls (76, 78, 80; 91; 99; 108) with at least one passage opening (77, 79, 81; 92; 101; 109), into at least three interconnected chambers and with at least one tool (86) arranged radially on the shaft (14; 62) in each chamber, wherein the tool (86) is adapted to transmit a tangential and/or an axial movement impulse to the solid particles, characterized in that the tank (11) is provided with a jacket for the thermal treatment of the solid particles, which surrounds the tank (11) in the circumferential direction over more than 180°, but less than 360 , and the jacket is provided along nearly the entire length of the device and is divided along the longitudinal axis of the tank (11) into one or several sections, and each section comprises one supply line (41, 42, 43; 97; 104) on one side and a discharge line (54; 98; 105) on the other side of the jacket which extend in the axial direction almost across the entire length of the jacket of each section and which also terminate in the jacket along this entire length, and the circumferential section having no jacket lies in the upper area of the tank (11), and at least one partition wall (76, 78, 80; 91; 99; 108) comprises only passage openings (77, 79, 81; 92; 101; 109) in its upper part.
3. Device according to claim 2, characterized in that the sections of the jacket permit of mutually independent heat supply and/or heat dissipation.
4. Device according to any one of claims 2 or 3, characterized in that the jacket comprises half pipes (40; 94; 102; 111) which are welded to the outer wall of the tank and are connected to the supply line (41, 42, 43; 97; 104) and to the discharge line (54; 98; 105).
5. Device according to any one of claims 2 to 4, characterized in that the partition walls (76, 78, 80; 91; 99; 108) can be cooled and/or heated.
6. Device according to any one of claims 2 to 5, characterized in that the shaft (14; 62) and the tools (86) form a centrifuging unit which can be cooled or heated.
7. Device according to any one of claims 2 to 6, characterized in that the drive motor is a pole-changeable motor or a motor of continuously variable speed.

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