Abstract:
A device for processing feedstock, includes a housing surrounding a processing chamber in which a rotational rotor having processing tools and mounted on a drive shaft is disposed around an axis. The feedstock is fed to the processing chamber via a material inlet and removed from the device via a material outlet. To facilitate assembly and disassembly of the device and to retool, maintain and repair or clean the device, it is provided according to the invention that the housing includes a first end wall, a material element in the shape of a hollow cylinder or hollow truncated cone, and a second end wall which are detachably connected to each other to form the processing chamber. The connection can be made by axially acting clamps, which clamp the first end wall against the second end wall by clamping the casing element.

Description:
[0001]    This nonprovisional application claims priority under 35 U.S.C. §119(a) to German Patent Application No. DE 10 2008 049 339.2, which was filed in Germany on Sep. 29, 2008, and which is herein incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a device for processing feedstock. 
         [0004]    2. Description of the Background Art 
         [0005]    Devices of this type belong to the field of mechanical process engineering, the goal of which is to process and transform source materials into a predetermined end product or intermediate product for further process steps. Possible types of processing and transformation are the different methods of mechanical crushing as well as agglomeration, mixing, separation, coating, drying, compacting and the like. The feedstock may vary in nature and largely involves substances from organic and anorganic chemistry, including dyes and pigments, the food and plastics industries as well as mineral substances. The range of applications for devices according to the definition of the species is correspondingly broad, these applications being adapted to the special characteristics of the feedstock, the desired end product and the type of processing through suitable selection of the processing tools and by maintaining preset process parameters. 
         [0006]    To minimize investment in new machinery and machine components, it is desirable from the perspective of the operator of such devices to be able to perform as many types of processing as possible using a single device, in order to adapt to different feedstock and objectives. However, this requires the ability to retool a device, if necessary by exchanging the machine components characteristic for processing, between one application and a subsequent application, which should be done as easily and quickly as possible in the interest of economical operation. 
         [0007]    Another aspect, which has to do with the ability to easily disassemble devices according to the definition of the species, lies in cleaning the device. In the chemical and pharmaceutical industries, in particular, great care must be taken when changing feedstock to avoid mixing the material previously processed with the material to be processed subsequently, which would compromise the material purity of the end or intermediate product. A similar consideration applies to the food industry, where a device according to the definition of the species must be completely and thoroughly cleaned after a standstill or change in feedstock for reasons of hygiene. It is therefore important to easily disassemble and reassemble devices according to the definition of the species, not only due to economic considerations, but also because this has a considerable influence on the quality of the end product. 
         [0008]    A mill having multiple milling sections, in which a cylindrical housing coaxially surrounds a rotor, is known from EP 0 226 900. The housing is sealed on one side by a welded-on base structure having integrated material and air supply means. On the diametrically opposed side, a cover connected to the housing via a flange joint and threaded bolts forms the housing closure. The rotor drive shaft is run on bearings on both sides in the area of the base structure and the cover. The rotor has grinding plates which are distributed over its circumference and interact with a stator on the inner circumference of the cylindrical housing. It is possible to disassemble this device only to a limited extent and with considerable effort. Due to the effort involved, it is not economical to retool the device for changing feedstock, which means that devices of this type are used mainly for invariable feedstock and production conditions. 
         [0009]    Another prior-art publication is DE 23 53 907 C3, which discloses an impact mill having a housing within which is disposed a rotor in the shape of a truncated cone, which has a plurality of grinding tools oriented in an approximately radial direction. The rotor drive shaft is run on bearings on only one side in the area of the base. The housing includes a central element in the shape of a hollow truncated cone, which forms a stator on the inside and is closed on the bottom by a base and on the top by a cover. The base and cover are connected via flange joints and threaded bolts, which are not illustrated in further detail. This mill has the advantage over the one described above in that both the cover and base are removable, which however is still associated with a considerable amount of work due to the presence of the flange joints. 
       SUMMARY OF THE INVENTION 
       [0010]    It is therefore an object of the invention is to further develop devices in the field of mechanical process engineering according to the definition of the species in such a way that they may be more easily disassembled and reassembled. Further objects of the invention are to optimize the flow of material within the device and to easily and thoroughly clean the device. 
         [0011]    The invention is based on the idea of enabling the device to be easily and quickly disassembled, due to a modular structure and a special type and arrangement of clamping component. For operators of devices according to the invention, this first provides the advantage that a device according to the invention may be disassembled and reassembled in a new configuration by providing only a few different machine components. This makes it possible to adapt devices according to the invention to external conditions, such as the type and quality of the feedstock or end product as well as the type of processing, which is important in particular when variable feedstock is used. Devices according to the invention therefore have a far greater range of applications than do those according to the prior art. Due to short retooling times, the economic feasibility of a device is guaranteed, even though the device is reconfigured. 
         [0012]    A further advantage of the devices according to the invention lies in the performance of cleaning work, which is necessary each time a product is changed for hygienic reasons in the food industry and to preserve the material purity of the end product in the chemical and pharmaceutical industries. The ability to easily and quickly disassemble a device according to the invention enables the machine components to be cleaned individually, so that areas that would otherwise be difficult to reach may be easily cleaned, and cleaning may be successful. By breaking the device down into individual machine components, these components may be cleaned by machine within a cleaning device, due to their smaller individual size. 
         [0013]    Not least, the ability to easily and quickly disassemble a device according to the invention provides advantages in the maintenance and repair thereof. Following disassembly, all machine areas are easily accessible and damaged parts may be easily replaced. 
         [0014]    These facilitating measures ultimately make the invention superior to known devices, not only with regard to the economical operation therefore, but in equal measure with regard to the quality of processing and consequently the quality of the resulting product. 
         [0015]    According to a particular embodiment of the invention, the clamping component extends from one end wall of the housing to the other and clamp the casing element surrounding the rotor. In this manner, the housing of a device according to the invention may be broken down into its components solely by removing the clamping component. The clamping component may be run in corresponding bores within the housing cross section as well as be provided outside the housing cross section in the manner of clamps. 
         [0016]    A comparable advantage is provided by another embodiment of the invention, in which clamping rings run along the outer circumference of the housing in the area of the contact joint of the individual housing components. Annular ridges on the outer circumference of the individual components, which lie together in pairs, provide an easy and quickly established connection between the individual housing components by tightening the clamping ring. The sides of the ridges interacting with the clamping ring may be conically tapered toward the outside in order to axially draw the components together when the clamping ring is tightened. 
         [0017]    Irrespective thereof, the ability to easily disassemble a device according to the invention is expressed in an embodiment in which parts of the drive unit, namely the bearing housing and the drive shaft mounted therein, are placed in the target position merely by inserting them from the outside into a receiving opening in a housing wall. The rotor then needs only to be mounted onto the drive shaft from the other side and fixed in place. In addition to fast assembly and disassembly of the drive components, this embodiment of the invention provides the additional advantage of spatially separating the drive system from the processing system. In this manner, unencapsulated portions of the drive system do not at any time during disassembly of the device according to the invention enter the area of the processing chamber, where under certain circumstances they would be able to contaminate the feedstock. In this connection, it is also advantageous to provide the housing wall accommodating the drive unit with a thick-walled design in order to establish a rigid connection to the housing when the drive unit is inserted, providing the advantage of enabling the rotor to run true. 
         [0018]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
           [0020]      FIG. 1  shows a longitudinal cross section of a first embodiment of a device according to the invention, having a clamp integrated into the housing; 
           [0021]      FIG. 2  shows a longitudinal cross section of a second embodiment of a device according to the invention, having externally situated clamps; 
           [0022]      FIG. 3  shows a longitudinal cross section of a third embodiment of a device according to the invention, having a clamp in the form of clamping rings; 
           [0023]      FIG. 4  shows a cross section of the device illustrated in  FIG. 1  along line IV-IV; 
           [0024]      FIG. 5  shows a view of the inside of the first end wall of a device according to the invention, excluding any further machine parts; and 
           [0025]      FIG. 6  shows an extended view of a partial cross section of a device according to the invention in the area of the contact joints between the casing element and end walls. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The descriptions below explain the invention on the basis of a mill which represents the different devices in the field of mechanical process engineering. A mill  1  of this type, which is illustrated in  FIGS. 1 and 4 , includes a housing  2 , which is formed by a casing element  4  in the shape of a hollow cylinder, i.e. closed on the circumferential side, through which pass annular circumferential cooling channel  5  in the present example. A first end wall  6  and a second end wall  7  close the end-face openings in casing element  4 , forming a grinding chamber  8 . To form a precisely fitting joint, a coaxial centering component is provided on inside  9  of first end wall  6  facing grinding chamber  8  and on inside  10  of second end wall  7  in the form of turned recesses  53  oriented coaxially to axis  3 , which with casing element  4  engages by its circumferential edge to form a positive fit. The inside edge of casing element  4  rests against an annular shoulder which is produced by turned recess  53  and forms a radial stop. It would also be conceivable to provide an annular groove running concentrically to axis  3  on insides  9  and  10  of end walls  6  and  7 , the edges of casing element  4  engaging with this groove. 
         [0027]    A grinding path  11 , whose impact surface forming the stator has an axial ribbing, is connected to casing element  4  in the radial inward direction toward grinding chamber  8 . Grinding path  11  includes multiple segments  13 —eight segments  13  in the present example—each of which has a curved strip section  12  on its narrow edge, by which means it is fixed precisely in position in a further turned recess  54  or an annular groove (not illustrated) on insides  9  and  10  or end walls  6  and  7  in a manner similar to casing element  4 . Turned recesses  53  and  54  are positioned relative to each other in such a way that turned recesses  53  lie deeper in insides  9  and  10  than do turned recesses  54 . 
         [0028]    First end wall  6  of casing element  4  and second end wall  7  have six aligned bores  15 , which run parallel to axis  3  and are distributed evenly over the housing circumference, these bores  15  being provided in first end wall  6  as fitting bores having an inner thread. Each bore  15  accommodates a tension member  16 , whose threaded foot is anchored in first end wall  6  and which further penetrates casing element  4  and second end wall  7  and whose projection on the outside of second end wall  7  is clamped in place by a capped nut  17 . 
         [0029]    Housing  2  is therefore held together only by tension members  16 , which clamp first end wall  6  and second end wall  7  together by clamping casing element  4  and grinding path  11 . The aforementioned positive fit or centering component in the contact joint between first end wall  6  and casing element  4  or grinding path  11  as well as second end wall  7  and casing element  4  or grinding path  11  ensure a coaxial arrangement of the individual parts. 
         [0030]    First end wall  6  has a circular opening  18  in the area of axis  3 , into which a cylindrical bearing housing  19  is inserted from the outside in the axial direction to form a precise fit. Bearing housing  19  has a circumferential annular flange  20 , which acts as a stop for the outside of first end wall  9  and thereby limits the depth at which bearing housing  19  is insertable into grinding chamber  8 . Inserting one or more distance plates (not illustrated) makes it possible to set the insertion depth, which simultaneously allows the width of the grinding gap to be adjusted when using a housing in the shape of a hollow truncated cone and a rotor (not illustrated). Bearing housing  19  is screwed to first end wall  6  in the area of annular flange  20 . The thick-walled design of first end wall  6  enables bearing housing  19  to be accommodated in a rigid manner. In the present example, the thickness of end wall  6  is at least 40 cm. 
         [0031]    In bearing housing  19 , a drive shaft  21  is rotationally mounted within bearing assemblies  22 , the rotation axis of drive shaft  21  coinciding with axis  3 . Seals  23  for encapsulating bearing housing  19  are provided in the area where drive shaft  21  exits bearing housing  19 . The end of drive shaft  21  situated outside housing  2  supports a multiple groove pulley  24  for connection to a drive, which is not illustrated, for example an electric motor. 
         [0032]    A rotor  26  having a cylindrical base member  27 , from which radial arms  28  extend a uniform circumferential distance apart on three axially staggered vertical planes relative to axis  3 , is mounted on diametrically opposed journal  25  of drive shaft  21 . The three planes are separated in the axial direction by annular channels  29  which run in the radial direction in the area of radial arms  28  and are open radially to the outside to form eddy zones. 
         [0033]    Due to the distance between radial arms  28  in the circumferential direction, slots  30  are formed which are in axial alignment with slots  30  on an adjacent plane. Grinding plates  31 , which extend over the entire length of rotor  26 , are inserted into slots  30 , i.e. each grinding plate  31  is held over its length on the three planes between each of two radial arms  28 . 
         [0034]      FIGS. 1 and 6 , in particular, show that grinding plates  31  are fixed in place in the axial direction by establishing a positive fit with the aid of a first locking ring  32  situated concentrically to axis  3  and a second locking ring  33 , which is clamped axially against the end faces of rotor  26  by screws, which are not illustrated in further detail. Locking rings  32  and  33  each have a circumferential collar  35  extending from the annular plane on their outer circumferences and a circumferential collar  36  extending to the same side from the annular plane on their inner circumferences. Collar  35  engages with complementarily shaped edge recesses in the diametrically opposed short edges of grinding plates  31  Segment  36  is in engagement with a complementarily shaped annular groove on the end faces of rotor  26 . The radial force which counteracts the centrifugal force and with which grinding plates  31  are held in place is transferred in this manner solely by the positive fit. In addition, first locking ring  32  simultaneously serves as a carrier for blades  34  used to generate a carrier air stream for transporting material through mill  1 . 
         [0035]    As shown in  FIGS. 1 and 5 , mill  1  is loaded with feedstock via a feed channel  38  which penetrates first end wall  6  in an eccentric manner and to which a supply line  39  is connected from the outside. In grinding chamber  8 , feed channel  38  empties into an annular channel  40  which is open to grinding chamber  8  and runs on inside  9  of first end wall  6 . Annular channel  40  runs concentrically around axis  3  and has its greatest axial height in the area of feed channel  38  in the circumferential direction of rotor  26 , this axial height decreasing linearly as it progresses and thereby transfers an axial motion component to the feedstock. The slope of the bottom of annular channel  40  may lie, for example, between 10 mm and 50 mm, preferably between 15 mm and 25 mm. Annular channel  40  as a whole is machined from the thick-walled first end face  6 , which thereby represents a monolithic component. For example, the thickness of first end wall  6  is at least 25 mm. To achieve greater slopes, the thickness may also be 40 mm or more. The radial width of annular channel  40  may extend over the entire free surface of inside  9  of first end wall  6 , between grinding path  11  and opening  18 . However, if the width extends only over a partial area of inside  9 , annular channel  40  preferably adjoins the inner circumference of grinding path  11  and therefore lies in the outer free circumferential area of inside  9 . 
         [0036]    The material is removed via a discharge hopper  41 , which is integrated into second end wall  7  and whose hopper opening faces grinding chamber  8  and whose edge adjoins grinding path  11  on the side. The overall hopper surface has a continuous contour and therefore is without sharp edges. Discharge opening  42  runs concentrically to axis  3  and ends flush with the outside of second end wall  7 , where a discharge line  43  is connected. The direction in which the feedstock flows through mill  1  is shown by arrows  44 . Due to the coaxial arrangement of discharge hopper  41 , the sufficiently finely ground feedstock must flow radially against the centrifugal force in the direction of rotation axis  3  when leaving grinding chamber  8 . This produces a sifting effect that retains any feedstock that is not sufficiently finely ground in the area of grinding path  11 . The separation limit may be set by suitably selecting the hopper inclination. Second end wall  7  is also provided with a thick-walled design, which enables annular channel  40  as a whole to be machined from thick-walled second end wall  7 . The thickness of the second end wall depends primarily on the design of discharge hopper  41  and may be, for example, 50 mm or more. 
         [0037]      FIG. 2  shows a further embodiment of the invention, which differs from the one described above only in the type of clamping component between first end wall  6 , casing element  4  and second end wall  7 . For this purpose,  FIG. 2  shows multiple clamping clips  45 , which run parallel to axis  3  along the outer circumference of housing  2 , i.e. outside housing  2 . Clip  45  has a first bent end  46  which engages with first end wall  6 , and a second bent end  47 , which is provided with an axial threaded bore. A clamping screw  48  is screwed into the threaded bore. supported on the outside of second end wall  7  and clamps housing  2  together in the axial direction. The arrangement of multiple clips  45  makes it possible to uniformly clamp housing  2  together. 
         [0038]    A third embodiment of the invention, which also permits easy and fast disassembly of the device according to the invention, is illustrated in  FIG. 3 . Mill  1  shown in this figure, in turn, corresponds to the one described in  FIGS. 1 and 4 , which differ only in the type of clamping component. In mill  1  shown in  FIG. 3 , first end wall  6  and casing element  4  each have a ridge  50  running around the outer circumference in their contact joints, the ridges being disposed in pairs on each side of the contact joint. Second end wall  7  and casing element  4  have a corresponding design in the area of their contact joint. By arranging a cross-sectionally U-shaped or V-shaped clamping ring  51 , which accommodates ridges  50  by its two legs, first end wall  6 , second end wall  7  and casing element  4  are held together in the axial direction. Due to a geometry of ridges  50 , in which outer edges  52  are inclined, an active axially clamping of both ridges  50 , and thus also of the two components, may be achieved ( FIG. 6 ). 
         [0039]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.