Abstract:
A device for removing fluids from particulate materials, including a container having a circular process chamber with a cylindrical external contour, an input device for inputting the materials into the process chamber, a discharge device for discharging the particulate materials freed of the fluid from the process chamber, a feed device for feeding a fluidizing agent from below into the process chamber, and at least one conditioning device for conditioning the fluidization agent in the direction of flow prior to the feed device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application of International Application No. PCT/EP2009/058977, filed on Jul. 14, 2009, which claims the benefit of European Patent Application No. 08012666.7, filed on Jul. 14, 2008, the entire contents of both applications are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments of the present invention relate to a device for removing at least fluids from a mixture of particulate materials, comprising a container having a circular process chamber with a cylindrical external contour, an input device for inputting a mixture of particulate materials into the process chamber, a discharge device for discharging the particulate materials at least partly freed at least of the fluids from the process chamber, a feed device for feeding a fluidizing agent from below into the process chamber and at least one conditioning device for conditioning, in particular heating, the fluidizing agent in the direction of flow prior to the feed device, wherein up to n walls and n cells extending in the vertical direction are provided in the process chamber, where nεN, a first cell is in operative connection with the input device, an n th  cell is in operative connection with the discharge device, the upper ends of the n cells are open, the first (n−1) cells are adapted to allow the fluidizing agent to flow therethrough from below through a base provided with first openings, and the walls between the n cells, from the first to the n th  cell, each comprise at least one second opening for passage of particulate materials, as well as a method for removing at least fluids from a mixture of particulate materials in such a device. 
     2. Description of the Related Art 
     A device for removing fluids and/or solids is described, for example, in EP 07002861.8-1266, not pre-published, and will be explained in more detail below with reference to  FIGS. 6 and 7 . 
       FIG. 6  shows a drying device  1  having a container  2 , comprising a substantially cylindrical outer skin  3 . Therein, the container  2  is placed on a rack  4  to not only make the container  1  accessible for maintenance also from below, but also to facilitate an evacuation of dried particulate materials into a further processing plant. It can be seen in  FIG. 6  that the external contour of the container  2  is substantially cylindrical. The geometrical structure of the container  2  and the components disposed therein is described below. 
     The container  2  set up on the rack  4  comprises at its lower end facing the rack  4 , a vaulted base  5  in which there is disposed a not illustrated fan impeller by which a fluidizing agent in particular, overheated vapor, is circulated in the container  2 . Within the container  2 , there is disposed a substantially cylindrical super heater  6 , so that the fluidizing agent is introduced from below into a substantially circular process chamber  20 , which is designed between the super heater  6  and the outer skin  3  and into which materials to be treated can be input by way of a not illustrated input device. Therein, the process chamber  20  is delimited at its lower end by a distribution plate  7  held by means of a distribution plate holder which allows the passage of the fluidizing agent through a plurality of not shown openings from below, but does not permit the materials to be treated to fall through. 
     Above the distribution plate  7 , there are disposed vertically aligned walls  8 , which extend from the external wall of the super heater  6  to the container wall, i.e. the outer skin, and form n cells between them. The walls  8  can reach down to the distribution plate  7  or form a free space in between. The cells formed by the walls  8  are open at the top, so that the fluidizing agent flows through the cells from the bottom up and fluidizes the materials or particles to be treated, partly carrying them along upwards and transporting them into a downstream cell, if necessary. The fluidizing agent does not substantially flow through the n th  cell or discharge cell provided with a not illustrated discharge device, so that any material entering such cell without a distribution plate from the top or along the distribution plate  7 , reaches the base area and can be removed from the discharge cell by way of the discharge device, for example, a conveying screw. 
     Above the walls  8 , there follow swirl blades  9  which can also be disposed, staggered, between the walls  8  in the circumferential direction and which correspond, in their vertical extension, approximately to the vertical extension of the walls  8  or extend beyond them, i.e. can be longer than the walls. The swirl blades  9 , each one at its lower side facing the walls  8 , are substantially aligned parallel to the walls  8 , so that the pressure side of the swirl blades  9  is oriented at an angle of 0° to the axial component of the flow velocity of the fluidizing agent. The swirl blades  9  are designed curved in the embodiment illustrated in  FIG. 6  and are oriented in such a way that the curve points from the input cell are in operative connection with the input device to the discharge cell, i.e. in the direction of flow of the particulate materials. If, for example, the input cell and the discharge cell are disposed next to each other interposing a wall  8 , then the curve of the swirl blades  9  assigned to the input cell points away from the discharge cell, so that the particle and material stream has to be transported over the entire perimeter of the container  2  and thus of the process chamber  20  in order to reach the discharge cell. 
     At their upper end, the swirl blades  9  comprise a curve of up to 35° to the axial component of the flow velocity of the fluidizing agent to divert the stream of the fluidizing agent as well as that of the materials in the circumferential direction. The swirl blades  9  constitute an extension of the walls  8 , wherein such extension can be designed with or without a gap between the swirl blades  9  and the walls  8 . The swirl blades  9  can form a simple or double-curved area, i.e. comprise a curve around both the axial component and a radial component in order to divert the flow of the fluidizing agent and the direction of motion of the material or the solids according to the requirements. Instead of a curve, an inclination of otherwise straight-walled swirl blades  9  can also be provided for diverting the direction of flow. 
     Above the swirl blades  9 , there is designed a transition area  10  embodied as a free space, which is provided without internals influencing the flow, so that the flow of the fluidizing agent as well as the transport of the same, together with the particles carried along in the fluidizing agent stream, can substantially take place unhindered. Such free space  10 , the so-called transition area, is designed in an annular form and allows an uninterrupted, free, circular passage of both the materials and the fluidizing agent in the horizontal plane. 
     Above the swirl blades  9  and the transition area  10 , there are disposed additional swirl blades  11 , which also comprise a simple or double-curved area on their pressure side, with an entry angle of up to 15° in relation to the axial flow velocity component. In the same nomenclature, the exit angle is up to 90°, wherein the inside diameter of the blading corresponds to the outside diameter of the super heater  6 . 
     The additional swirl blades  11  are a component of a dust separator  12 , the outside diameter of which is smaller than the outside diameter of the process chamber  20  and thus smaller than the outside diameter of the container housing in the area of the walls  8  and the swirl blades  9 . The outside diameter of the additional swirl blading corresponds to the outside diameter of the dust separator  12 . By adapting the additional swirl blading to the swirl blades  9 , the construction of the device  1  will be optimized with regard to the pressure loss, so that the overall device can be operated at a high level of efficiency. Therein, the external contour  3  of the container  2  is cylindrical at least up to the level of the swirl blades, in the present case up to the level of the dust separator  12  or the additional swirl blades  11 , which avoids a material-intensive design of the container  2 , preferably designed as a pressure container. The swirl blading generates and supports a pre-swirl or the swirl flow above a fluidized bed present in the chamber  20 , which ensures that the required and desired further transport from the input cell to the discharge cell is not only supported for fine particles. Within the dust separator  12 , there is generated a centrifugal field in which the dust particles and particulate materials carried along are moved around externally and are discharged through an opening. 
     Above the additional swirl blades  11 , there are disposed return blades  13 , oriented opposite the swirl direction, which redirect the swirl of the fluidizing agent, transforming it into a static pressure to feed the fluidizing agent into the super heater  6 . The return or back-swirl blades  13  also comprise a simple or double-curved or inclined area with an entry angle of up to 90° in relation to the axial flow velocity component of the fluidizing agents, wherein the exit angle is up to 10° in the same nomenclature. The inside diameter of the blading corresponds to the outside diameter of an outlet pipe  14 , while the outside diameter of the blading corresponds to the inside diameter of the super heater  6 . By way of the upper opening  14   a  as shown in  FIG. 6 , vapor can escape from the container  2  and can be reused, preferably energetically, in another process. 
       FIG. 7  illustrates a horizontal section along the line D-D of  FIG. 6 . At the lower end of  FIG. 7 , there is shown the input cell  15 , which is in operative connection with the not illustrated input device, for example, a conveying screw, and which is disposed directly next to the discharge cell  17 , wherein the input cell  15  and the discharge cell  17  are fluidically separated from each other in such way that a direct transition of the material from the input cell  15  to the discharge cell  17  is prevented. Starting from the input cell  15 , it follows a plurality of processing cells  16  that are separated from each other by the intermediate walls  8 . Therein, the intermediate walls  8  can border directly on the container wall or can be suspended at a certain distance thereof within the annular process chamber  20  which is delimited by the distribution plate  7  at its lower side and by the lower side of the swirl blades  9  at its upper side. Within the processing cells  16 , intermediate heating walls  18  can be disposed to provide additional thermal energy for the drying process. 
     Furthermore, EP 0 955 511 B1 describes an alternative device for drying granular material by means of overheated vapor in which an arrangement for automatically regulating a particle flow from cell to cell, preferably comprising a shutter for an opening of a wall between two adjacent cells, is provided between all processing cells, including an input cell and a discharge cell. However, the use of such shutters involves the risk that an accumulation of granular material occurs before each closed shutter, so that the respective shutter gets jammed and can thus no longer be opened purposefully, with the consequence that neither the degree of drying nor the discharge quantity of dried granular material can be adjusted reproducibly. 
     SUMMARY OF THE INVENTION 
     Therefore, an object of embodiments of the present invention is to further develop the device of the above-mentioned type in such way that it overcomes the disadvantages of the prior art. 
     This object is achieved according to the embodiments of the present invention by attaching at least one boundary wall for delimiting an intermediate space between the (n−1) th  cell and the n th  cell to the wall between the (n−1) th  cell and the n th  cell, wherein the intermediate space is connected to the (n−1) th  cell by way of the second opening in the wall between the (n−1) th  cell and the n th  cell, which, in particular, is designed in the form of a recess at the side of said wall facing the base, the intermediate space can be connected to the n th  cell by way of at least a third opening, which, in particular, is designed in the form of a recess in the boundary wall at the side of the boundary wall facing the base, the intermediate space can be closed by the boundary wall at the upper end thereof opposite the base and to the side, and fluidizing agent can flow from below through first openings in the base, and the third opening can be closed or opened at least temporarily, at least partly by at least one closing member of the discharge device. 
     Therein, it can be provided that the closing member can be moved, preferably controlled, in particular depending on output data of at least one sensor, by way of a driving device of the discharge device. 
     Therein, it is preferred that a fluidized bed of the particulate material can be generated by the fluidizing agent in the first (n−1) cells and the intermediate space, and the sensor measures at least one characteristic quantity of the fluidized bed, wherein preferably no fluidized bed is present in the n th  cell. 
     Therein, it is proposed by the invention that a differential pressure of the fluidized bed can be measured by way of the sensor, preferably, by means of a first detector within the fluidized bed and a second detector outside, in particular, above the fluidized bed, in particular in the (n−1) th  cell. 
     Furthermore, it can be provided that the driving device comprises at least one motor, such as a geared motor or a stepper motor, preferably with a positioner for positioning the closing member, and/or the closing member is connected to a motor of the driving device by way of a shaft. 
     Therein, it is proposed that the closing member comprises a circular segment cross-section disposed coaxially to the shaft. 
     Moreover, preferred embodiments according to the invention are characterized in that at least two closing members are provided, wherein preferably the closing members are disposed and evenly distributed on a concentric circle around the shaft. 
     It is also proposed by the embodiments of the present invention that each closing member can be moved from the bottom up along the third opening, preferably, on a circular arc. 
     Furthermore, it can be provided that each closing member is disposed in the n th  cell and the associated driving device is disposed outside the container, so that the shaft between the driving device and the closing member passes through the external contour of the container. 
     It can also be provided that the boundary wall, in particular a roof part of the same, extends at the upper end of the intermediate space from the third opening to the second opening in the wall between the (n−1) th  cell and the n th  cell, preferably inclined and/or bent upwards. 
     Moreover, it is proposed that the discharge device comprises a conveying device, which runs at least partly in the n th  cell. 
     It can also be provided that the discharge device comprises a variable-frequency inverter. 
     Furthermore, embodiments of the invention can be characterized in that at least a fourth opening is disposed above the second opening in the wall between the (n−1) th  cell and the n th  cell, so that particulate material can enter from the (n−1) th  cell into the n th  cell above the intermediate space. 
     Therein, it is proposed that the fourth opening can be at least partially and temporarily closed, preferably by a further closing member of the discharge device. 
     Furthermore, preferred embodiments of the present invention are characterized by a wall between the n th  cell and the first cell, wherein such wall comprises no opening. 
     It can also be provided that the n cells are disposed concentrically around the conditioning device preferably comprising a super heater. 
     Moreover, it is proposed that swirl blades, which are inclined or curved in the direction of flow of the particulate materials from the first cell to the n th  cell are disposed above the walls, wherein the outside diameter of the swirl blades is not greater than the outside diameter of the walls and the swirl blades are surrounded by an external cover, which does not project radially beyond the external cover which surrounds the walls. 
     Embodiments of the present invention also provide a method for removing at least fluids from a mixture of particulate materials in a device according to the embodiments of the present invention are characterized in that the residence time of the particulate material in the process chamber of the device is determined depending on a fluidized bed differential pressure in the process chamber. 
     Therein, it can be provided that, for discharging the particulate materials at least partly freed at least of fluids from the process chamber, each closing member closing the third opening is at first turned from its respective closing position into an opening position preferably completely releasing the third position, preferably gliding past the third opening from the bottom up, and the closing member is subsequently held in the opening position for a first certain duration. 
     Alternatively, it is proposed that, for discharging the particulate materials at least partly freed at least of fluids from the process chamber, each closing member is at first brought into a stationary state for a second certain duration, in which state the third opening is partly opened, and the third opening is further opened, in particular completely opened, at least once for a third certain duration during the second certain duration, wherein, preferably for opening the third opening at least in some areas, at least one closing member is moved past the third opening from the bottom up. 
     Moreover, it can be provided that, for at least partly closing the third opening, preferably, depending on the first or second and/or third duration, at least one closing member first closes the third opening either from the top down or from the bottom up. 
     Finally, it is also proposed according to the embodiments of the present invention that the process chamber is filled with a mixture of particulate materials and a fluidizing agent is fed into the process chamber in such way that the fluidized bed builds up at least in the (n−1) th  cell, at least up to the fourth opening. 
     Thus, embodiments of the present invention are based on the surprising finding that, when operating the drying device with a continuous input of particulate materials to be dried and a continuous discharge of dried material, a fluidized bed differential pressure gradient is induced, which is sufficient as a driving force for transport of the particulate materials to be dried in the fluidized bed from processing cell to processing cell, on the one hand, and ensures a permanent particle movement before a closing member, on the other hand, which is only necessary between the last processing cell, which spreads the fluidized bed, and the discharge cell without a fluidized bed, if the closing member is not used for closing an opening of a wall between said last processing cell with a fluidized bed and the discharge cell without a fluidized bed, but for closing an opening of an intermediate space between said last processing cell and the discharge cell, so that no jamming of particles and/or no accumulation of a product difficult to fluidize will occur before the closing member. 
     Furthermore, based on the knowledge obtained from the embodiments of the present invention, when the quantity of particulate materials fed into the fluidized bed is increased, the fluidized bed differential pressure will increase so that, for guaranteeing stationary process conditions in the fluidized bed with an approximately constant filling and product residence time, an adjustment of the discharge of the particulate materials at least partly freed at least of fluids has to be made depending on said fluidized bed differential pressure. This enables a controlled quantity of particulate materials in the fluidized bed, with a simultaneous optimization of the removal of the fluids from the particulate material. Furthermore, it is ensured that the fluidized bed in the process chamber will not become depleted of fluidized material and is thus maintained even in case of a short-time interruption or reduction of the feeding of said mixture of particulate materials into the process chamber. 
     Further features and advantages of the embodiments of the present invention will be apparent from the following description in which exemplary embodiments of the invention are explained in more detail based on the accompanying drawings described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a first perspective local sectional view of a device according to an embodiment of the present invention; 
         FIG. 2  shows a second perspective local sectional view of the device of  FIG. 1 ; 
         FIG. 3  shows a third perspective local sectional view of the device of  FIGS. 1 and 2 ; 
         FIG. 4  shows a perspective view of a closing device of the device of  FIGS. 1 to 3 ; 
         FIGS. 5   a  to  5   c  show local sectional views of a processing cell and a discharge cell of the device of  FIGS. 1 to 3 , with different positions of the closing device of  FIG. 4 ; 
         FIG. 6  is a perspective local sectional view of a known device; and 
         FIG. 7  is a sectional view taken along line D-D in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     A drying device according to the embodiments of the present invention constitutes a further development of the device  1  as described with reference to  FIGS. 6 and 7 , wherein the same parts are denoted by the same reference numerals and are not described again herein. More precisely, the drying device  1  according to the embodiments of the present invention as shown in  FIGS. 1 to 3  in different perspective local sectional views, substantially differs from the known drying device  1  of  FIGS. 6 and 7  in that it has a closing device  40 , which is illustrated in detail in  FIG. 4 . 
     According to  FIG. 4 , the closing device  40  comprises a shaft  41  for connecting two closing members  42   a ,  42   b  to a driving device  43 . The closing members  42   a ,  42   b  are disposed, in cross-section, on a circle, which is concentric to the shaft  41 , and is evenly distributed along the circle, so that they face each other, so to speak. 
     As can be seen from  FIG. 1 , the driving device  43  of the closing device  40  is disposed outside the outer skin  3  of the drying device  1 , while the closing members  42   a ,  42   b  are disposed rotatably in the discharge cell  17  by way of the shaft  41 . In the area of the closing members  42   a ,  42   b , the discharge cell  17 , which does not include a distribution plate, is not disposed, so to speak, directly adjacent to the last processing cell  16 , which includes a distribution plate (not shown) as illustrated in  FIGS. 1 and 3  while  FIGS. 5   a - 5   c  depict the position of the distribution plate. It is rather clearly visible in  FIGS. 1 to 3  that an intermediate space, which is subsequently called loosening space  19  for reasons that will be explained in more detail below, is disposed between the processing cell  16  and the discharge cell  17 . For this, a boundary wall  19   b  is disposed at the wall  8   a  between said processing cell  16  and the discharge cell  17  in the area of the opening  8   b , which constitutes a recess of the wall  8   a  at the end facing the distribution plate, so that the loosening space  19  is connected to said processing cell  16  by way of the opening  8   b  and to the discharge cell  17  by way of a further opening  19   a . As can best be seen in  FIGS. 5   a - 5   c , the loosening space  19  is delimited by the boundary wall  19   b  at its top and side, and is delimited at its bottom by the distribution plate  7 . 
     The opening  19   a  of the loosening space  19  can be closed by way of one of the closing members  42   a ,  42   b , as illustrated, for example, in  FIG. 2 . However, if none of the closing members  42   a ,  42   b  are disposed in front of the opening  19   a , as illustrated, for example, in  FIG. 1  or  3 , particulate materials from said processing cell  16  can enter into the discharge cell  17  by way of the loosening space  19 , from which they can then be led out by way of a conveying device  30 , namely in the area of an opening  17   a , which is best illustrated in  FIGS. 1 and 3 . 
     The mode of operation of the drying device  1  is hereinafter explained with reference to  FIGS. 5   a  to  5   c.    
     If a mixture of particulate materials is constantly introduced into the process chamber  20 , more precisely into the input cell  15  in the process chamber  20 , and a fluidizing agent, for example, in the form of vapor heated up in the super heater  6  and blown by way of the fan impeller in the base  5  through openings in the distribution plate  7  from the bottom up, is simultaneously introduced into the process chamber  20 , then a fluidized bed is built up in the process chamber  20  and with it, a fluidized bed differential pressure. Such fluidized bed differential pressure is proportional to the quantity of particulate materials in the fluidized bed. The driving force for the materials transport from the input cell  15  to the discharge cell  17  consists in a permanent fluidized bed differential pressure difference, which adjusts from the input towards the discharge in case of a continuous operation of the drying device  1 . Therein, the materials transport goes from the input cell  15  via the processing cells  16  into the discharge cell  17 , and through openings in the intermediate walls  8 , such as, for example, the opening  8   b  in the intermediate wall  8   a  between the last processing cell  16  with a distribution plate  7  and the discharge cell  17  without a distribution plate  7 . In order to guarantee stationary process conditions in the fluidized bed, with an approximately constant filling and product residence time, materials must be able to flow out according to the inflow of the materials from the fluidized bed, i.e., must be able to leave the drying device  1  through the opening  17   a . This can occur in different ways. 
     Before the flowing out of materials is described in more detail, it should be mentioned that, in case of a closure of the opening  19   a  of the loosening space  19  by the closing member  42   a , as shown in  FIG. 5   a , due to the inclination of the roof part of the boundary wall  19   b  from the opening  19   a  of the loosening space  19  to the opening  8   b  in the wall  8   a , and upwards, it is ensured that a fluidizing agent entering through the distribution plate  7  into the loosening space  19  enters into the processing cell  16  with a distribution plate  7  along the arrow B and thus, a constant solids movement is guaranteed before the closing member  42   a  causes a closed state of the loosening space  19 . Therefore, a loosening of the particulate materials really takes place in the loosening space  19 , which avoids forming of particularly coarse product particles, e.g., by agglomeration, during a longer closing phase, which can then no longer be discharged from the process chamber  20 , but would rather lead to an obstruction in the loosening space  19 . In the following, three variants of discharging material from the process chamber  20  by way of the opening  17   a  are described: 
     First Variant 
     The closing member  42   a  is turned or rotated clockwise from the closing position as shown in  FIG. 5   a  into the opening position as shown in  FIG. 5   b . This direction of rotation is important because it guarantees that the closing member  42   a  glides past the opening  19   a  from the bottom up, so that coarser particles will not lead to a jamming between the closing member  42   a , on the one hand, and the wall  8   a  and/or the distribution plate  7 , on the other hand. 
     The complete unobstruction of the opening  19   a  as shown in  FIG. 5   b  will then cause coarser particles to be discharged from the loosening space  19  through an intense pulse exchange with the remaining fluidizing solid in the fluidized bed. Therein, the driving force for that transporting effect is provided by the fluidized bed differential pressure, which is also approximately present between the loosening space  19  and the discharge cell  17 . 
     After a fixed opening time, the closing member  42   b  is then brought back in its closing position and will remain there for a fixed duration. Therein, the speed of the rotary movement must be so high that the fluidized bed before the discharge cell  17  will not be depleted of solids through too long an opening time of the loosening space  19 . Therein, a speed of 10 to 20 revolutions per minute is desirable. 
     On the shaft  41 , several closing members can be disposed to influence the opening times. 
     If the product stream from the processing cell  16  into the discharge cell  17  becomes too large, one of the closing members  42   a ,  42   b  can be turned into an only partly opened position, see  FIG. 5   c , for example, and remain in this position. 
     The duration of both the closed and the opened state of the loosening space  19  is to be controlled depending on a fluidized bed differential pressure. The latter is measured by way of two pressure sensors  44   a ,  44   b , wherein the one pressure sensor  44   a  is disposed above the fluidized bed, and the other pressure sensor  44   b  is disposed within the fluidized bed in direct proximity above the distribution plate  7  of the processing cell  16 , as can be seen in  FIGS. 1-3 . 
     The closing members  42   a  and  42   b  are selectively moved into their individual positions by way of the driving device  43 , which can comprise a geared motor with a positioner. 
     For facilitating the discharge of the particulate material from the discharge cell  17 , the conveying device  30  can be used. 
     Second Variant 
     The closing member  42   a  can be in a partly opened position, as shown in  FIG. 5   c , in which the lower edge of the closing member  42   a  is above the lower edge of the opening  19   a  of the loosening space  19 . Through the opening of the loosening space  19  thus given, particulate materials from the processing cell  16  can enter into the discharge cell  17  after passing the loosening space  19 , wherein the quantity thereof can be controlled depending on a measured fluidized bed differential pressure by changing the position of the closing member  42   a.    
     For avoiding obstructions of the loosening space  19  by coarse particles, the closing member  42   a  can completely unobstruct the opening  19   a  in a preset rhythm for a short duration, as shown in  FIG. 5   b , namely, to enable the discharge of coarse particles that may be present. So, in case of a complete opening or unobstruction of the opening  19   a , a kind of “cleaning” of the loosening space  19  and thus also in the fluidized bed present before the closing member  42   a  in its partial closing position takes place. 
     If, in the rotary movement of the closing member  42   a  for closing the opening  19   a , a torque which exceeds a preset maximum value during a clockwise rotation should occur, the rotation can also take place anticlockwise. Moreover, this measure serves to remove any particles that may be jammed between the closing member  42   a  and the borders of the opening  19   a  of the loosening space  19 . 
     The necessary rotary movement of the closing members  42   a ,  42   b  also depends on the number of the closing members. 
     Third Variant 
     Through a further opening  8   c  in the wall  8   a  between the processing cell  16  and the discharge cell  17 , which is visible in  FIG. 1 , it is possible to allow particulate materials to flow directly from the processing cell  16  into the discharge cell  17 , namely above the loosening space  19 . For this purpose, the fluidized bed within the processing cell  16  has to reach at least up to the lower edge of the opening  8   c.    
     If the opening  8   c  is disposed in the area of the nominal fluidized bed level, it functions as a stationary weir that allows particulate materials to enter from the processing cell  16  into the discharge cell  17 . 
     If one combines a particle transport by way of the opening  8   c  with a transport through the loosening space  19 , either according to the first variant or according to the second variant, then substantially coarse particulate materials will flow through the loosening space  19 , which helps to improve a controlled fluidization. 
     The features disclosed in the above description, in the drawings, and in the claims can be essential to the realization of the invention in its different embodiments, both individually and in any combination. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Drying device 
           2  Container 
           3  Outer skin 
           4  Rack 
           5  Base with fan impeller 
           6  Super heater 
           7  Distribution plate 
           8  Wall 
           8   a  Wall 
           8   b  Opening 
           8   c  Opening 
           9  Swirl blade 
           10  Transition area 
           11  Additional swirl blade 
           12  Dust separator 
           13  Return blade 
           14  Outlet pipe 
           14   a  Opening 
           15  Input cell 
           16  Processing cell 
           17  Discharge cell 
           17   a  Opening 
           18  Intermediate heating wall 
           19  Loosening space 
           19   a  Opening 
           19   b  Boundary wall 
           20  Process chamber 
           30  Conveying device 
           40  Closing device 
           41  Shaft 
           42   a ,  42   b  Closing member 
           43  Driving device 
           44   a ,  44   b  Pressure sensor 
         A, B, B′, C, C′ Direction of flow 
         d Direction of rotation