Abstract:
Provided is a powder and granular material crushing and sizing apparatus in which stators are easy to disassemble and assemble, i.e. in which disc-like rotors and stators can be cleaned and replaced easily. A drive shaft, on which a plurality of disc-like rotors are disposed, is supported in a cantilever manner on a bearing housing. A plurality of stators are disposed on a holder to make up a stator assembly. The stator assembly is detachably disposed in the bearing housing. An opening is formed in a side wall of the casing. The disc-like rotors and the stator assembly are housed via the opening, and the casing is detachably disposed on the bearing housing. ion.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a powder and granular material crushing and sizing apparatus for sizing, to a predetermined particle size, various wet or dry materials such as pharmaceuticals, foodstuffs, fodder, chemicals, fertilizers, powdered coal, limestone or ceramics materials that are granulated or formed by various apparatuses. More particularly, the present invention relates to a powder and granular material crushing and sizing apparatus that crushes granules (lumps) of a target particle size or greater, such as wet aggregates or dry blocks granulated or formed by various apparatuses, and that sizes the granules within a given particle size range. 
         [0003]    2. Description of the Related Art 
         [0004]    Mixing, granulating and sizing operations of powder and granular materials are widely carried out in numerous industrial fields, such as in the pharmaceutical and food industries. Particle size adjustment is an important unit operation in production processes, with a view to, for instance, improving the quality of the powder and granular material, increasing fluidity during fluidized drying, and improving handling. A crushing and sizing apparatus is used for the above particle size adjustment operation. 
         [0005]    The applicant has disclosed such a powder and granular material crushing and sizing apparatus in Japanese Patent No. 4113222. 
         [0006]    The powder and granular material crushing and sizing apparatus comprises a plurality of disc-like rotors fixedly supported, at intervals, by a drive shaft provided in a horizontal direction; and a plurality of semi-circular arc stators provided below the disc-like rotors and that oppose disc faces of the peripheral edge thereof, the stators having inclined faces such that the gap between the stators and the disc faces of the disc-like rotors becomes narrower towards the peripheral edges of the disc-like rotors; wherein the disc faces of the disc-like rotors and the inclined faces of the stators form hopper-like gap portions where a powder and granular material is held, and wherein the narrowest gap portions between the peripheral edges of the disc-like rotors and the stators form crushing and sizing sections. 
         [0007]    In the above powder and granular material crushing and sizing apparatus, the powder and granular material to be processed is fed, from above the disc-like rotors, to the gap portions that are delimited by the peripheral-edge disc faces of the disc-like rotors and the inclined faces of the stators. The powder and granular material is crushed and sized at the narrowest gap portions and is discharged downwards. 
         [0008]    In the above powder and granular material crushing and sizing apparatus, the disc-like rotors and the stators had to be disassembled to be cleaned. However, the structure of the apparatus is such that the plurality of stators is assembled, interposing spacers between the disc-like rotors, to a plurality of fixed shafts disposed across the interior of a casing. Therefore, removal and mounting of the stators was cumbersome. To replace the disc-like rotors, moreover, it was necessary to remove first a powder and granular material charging casing and a casing main body, remove next a belt from a pulley, remove a drive shaft, with the disc-like rotors fixed thereto, from the bearing that holds the drive shaft, and remove thereafter the disc-like rotors from the drive shaft. To mount the disc-like rotors, the above procedure had to be carried out in reverse order, which made for a cumbersome removal and mounting of the disc-like rotors. 
       SUMMARY OF THE INVENTION 
       [0009]    In the light of the above, it is an object of the present invention to provide a powder and granular material crushing and sizing apparatus in which stators are easy to disassemble and assemble, i.e. in which disc-like rotors and stators can be cleaned and replaced easily. 
         [0010]    With a view to attaining the above goal, the powder and granular material crushing and sizing apparatus of the present invention is a powder and granular material crushing and sizing apparatus in which a powder and granular material fed through an upper feeding opening of a casing is crushed and sized at gaps that are formed by peripheral-edge disc faces of a plurality of disc-like rotors disposed, at a predetermined spacing, on a horizontal drive shaft, and a plurality of stators disposed between lower peripheral edges of the plurality of disc-like rotors, and in which the crushed and sized powder and granular material is discharged towards a bottom discharge opening of the casing; wherein the drive shaft is supported in a cantilever manner on a bearing housing, the plurality of stators are disposed on a holder to make up a stator assembly, the stator assembly is detachably disposed in the bearing housing, an opening is formed on a side wall of the casing, the disc-like rotors and the stator assembly are housed via the opening, and the casing is detachably disposed on the bearing housing. 
         [0011]    In the invention, the casing is detachably disposed on the bearing housing in such a manner that the casing covers the drive shaft. The casing can thus be removed easily. The stator assembly provided with the plurality of stators is detachably disposed on the bearing housing. The plurality of stators can be removed thus simultaneously from the disc-like rotors by removing the stator assembly from the bearing housing. As a result, the disc-like rotors and the stators can be cleaned easily and quickly. 
         [0012]    According to the present invention, the free end of the drive shaft will be exposed, simply by removing the casing. Thus the exchange of the disc-like rotors is easy. A plurality of stators can be exchanged at a time, by removing the stator assembly, and by mounting another stator assembly that is prepared for exchange. In this way, the exchange of the rotors and the stators can be completed easily and quickly. Consequently a quick adjustment of the spacing at the crushing and sizing section (at the narrowest gap portion), i.e. the adjustment of the particle size, is possible. 
         [0013]    In the above invention, the stator assembly may be formed by arranging the stators, shaped as a semicircular arc and having a substantially triangular cross-sectional shape, at band-like portions formed on a holder having a semi-tubular shape concentric with the disc-like rotors and in which a plurality of long holes are formed, along a circular arc, at positions corresponding to the lower peripheral edges of the disc-like rotors, the band-like portions being formed between the long holes. 
         [0014]    In the invention, there is prepared a plurality of stator assemblies with modified long hole width, such that the spacing between the crushing and sizing sections (narrowest gap portions), i.e. the sizing particle size, can be adjusted very quickly by exchanging the stators assemblies. 
         [0015]    In the above invention, cylindrical pins having a flat portion in a part thereof may be standingly provided on the peripheral-edge disc faces of the disc-like rotors, in such a manner that the flat portion tilts rearwards in an advance direction of the disc-like rotors as the flat portion extends towards the peripheral edge of the disc-like rotor. 
         [0016]    In the invention, the material to be processed is pushed out by the flat portions of the pins, accompanying the rotation of the disc-like rotors, towards the gaps between the peripheral edges of the disc-like rotors and the stators. This allows increasing the crushing and sizing efficiency of the material to be processed. 
         [0017]    In the above invention, an intermediate portion of the pins, in the longitudinal direction, may be shaped as a non-cylinder, holes having a shape corresponding to a cross sectional shape of the intermediate portion of the pins may be formed in the disc-like rotors, and the flat portions of the pins may be positioned so as to face towards a predetermined direction by inserting the intermediate portion of the pins into the holes. 
         [0018]    In the invention, the flat portions are positioned by simply fitting, through insertion, the intermediate portion of the pins, in the longitudinal direction, into holes in the disc-like rotors. This makes the pin mounting operation easier. 
         [0019]    In the above invention, the stators may be formed of polytetrafluoroethylene. 
         [0020]    The invention allows preventing adhesion (deposition) of the material to be processed thanks to the smoothness of the polytetrafluoroethylene surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is an exploded perspective-view diagram illustrating conceptually a powder and granular material crushing and sizing apparatus according to the present invention; 
           [0022]      FIG. 2  is a vertical cross-sectional diagram of the powder and granular material crushing and sizing apparatus according to the present invention; 
           [0023]      FIG. 3  is a perspective-view diagram illustrating a disc-like rotor of the powder and granular material crushing and sizing apparatus according to the present invention; 
           [0024]      FIG. 4  is an exploded perspective-view diagram of the disc-like rotor illustrated in  FIG. 3 ; 
           [0025]      FIG. 5  is a front-view diagram of the disc-like rotor illustrated in  FIG. 3 ; 
           [0026]      FIG. 6  is a side-view diagram of the disc-like rotor illustrated in  FIG. 3 ; 
           [0027]      FIG. 7  is a diagram illustrating the way in which pins are embedded in the disc-like rotor illustrated in  FIG. 3 , wherein  FIG. 7A  is a front-view diagram and  FIG. 7B  a cross-sectional diagram; 
           [0028]      FIG. 8  is a diagram illustrating the way in which pins are embedded in the disc-like rotor illustrated in  FIG. 3 , wherein  FIG. 8A  is a front-view diagram and  FIG. 8B  a cross-sectional diagram; 
           [0029]      FIG. 9  is a diagram illustrating a stator assembly in the powder and granular material crushing and sizing apparatus according to the present invention, with stators and a holder disassembled, wherein  FIG. 9A  is a perspective-view diagram of the stators,  FIG. 9B  is a perspective-view diagram of the holder, and  FIG. 9C  is an enlarged cross-sectional diagram of a portion along line I-I in diagram of  FIG. 9A , illustrating a cross section structure of the stators; 
           [0030]      FIG. 10  is a diagram illustrating a stator assembly in the powder and granular material crushing and sizing apparatus according to the present invention, wherein  FIG. 10A  is a perspective-view diagram illustrating the whole, and  FIG. 10B  is an enlarged cross-sectional diagram of a portion, along line II-II in diagram of  FIG. 10A , illustrating a fixed structure of the stators and the holder; and 
           [0031]      FIG. 11  is a cross-sectional diagram illustrating an enlargement of a relevant portion of a crushing and sizing section in the powder and granular material crushing and sizing apparatus according to the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]    The powder and granular material crushing and sizing apparatus according to the present invention will be explained in detail below on the basis of embodiments illustrated in the drawings. 
         [0033]    The powder and granular material crushing and sizing apparatus  1  according to the present invention illustrated in the drawings comprises a power section  10 , a bearing section  20 , and a powder and granular material crushing and sizing section  30 . 
         [0034]    In the power section  10 , a motor  11  is supported on a motor base  12 , and an output shaft  13  protrudes in the horizontal direction. 
         [0035]    In the bearing section  20 , a tubular bearing housing  21  is supported on a base  22 , and a rectangular bracket  23  is disposed at one end of the bearing housing  21 . Inside the bearing housing  21 , both ends of a drive shaft  24  are supported by ball bearings  25 ,  26 , as illustrated in  FIG. 2 . One end of the drive shaft  24  extends into the crushing and sizing section  30  via the bracket  23 . The cross section, perpendicular to the shaft center, of an extension  24   a  of the drive shaft  24  is rectangular in shape. The other end  24   b  of the drive shaft  24  is coupled to an output shaft  13  of the motor  11  via a coupling  14 . 
         [0036]    The crushing and sizing section  30  comprises a casing  31  shaped as a square tube that has a powder and granular material feeding opening  31   a  at the upper portion, and a discharge opening  31   b  of crushed and sized powder, at the lower portion. An opening  31   c  is formed at one side face of the casing  31 . One side face of the bracket  23 , on the side of the crushing and sizing section  30 , is cut out, to a constant depth, over the entire periphery of the side face. The opening  31   c  of the casing  31  is fitted to the cutout portion  23   a  of the bracket  23  in a manner so as to form a spigot ferrule joint, and is fixed to the bracket  23  by some appropriate means (not shown), such as a snap fastener (gate fastener), or by way of bolts and nuts. In that state, the extension  24   a  of the drive shaft  24  is housed inside the casing  31 . 
         [0037]    A plurality of (in the present embodiment, five) disc-like rotors  32 , which are one of the main elements of the crushing and sizing section  30 , are fitted to the extension  24   a  of the drive shaft  24 . 
         [0038]    As illustrated in  FIG. 3  to  FIG. 6 , the disc-like rotors  32  comprise each a rectangular hole  32   a , corresponding to the extension  24   a  of the drive shaft  24 , formed in the central portion of the disc-like rotor; a plurality of (in the present embodiment, six) cylindrical pins  33  equidistantly disposed at the peripheral edge of both disc faces, and a plurality of (in the present embodiment, six) cylindrical pins  34  equidistantly arrayed, between respective pins  33 , further out towards the peripheral edge than the pins  33 . 
         [0039]    As illustrated in  FIG. 4  and  FIG. 7 , a large-diameter cylindrical portion  33   a  is formed at an intermediate portion, in the longitudinal direction, of each pin  33 . The cylindrical portions  33   a  are inserted into circular holes  32   b  that are formed in the disc-like rotors  32 , and are fixed by welding or the like. As illustrated in  FIG. 4  and  FIG. 8 , the pins  34  have each a prism portion  34   a  at an intermediate portion in the longitudinal direction, and comprise each a flat portion  34   b  that results from partially cutting out both ends of the cylindrical portion in such a manner that the cross section in the longitudinal direction is shaped as a D. As illustrated in  FIG. 5  and  FIG. 8 , the pins  34  are fixed by inserting the prism portions  34   a  into respective rectangular holes  32   c  that are formed in the disc-like rotor  32 , and by welding or the like, in such a manner that the flat portions  34   b  are disposed tilting rearwards in the advance direction of the disc-like rotors  32  as the flat portions  34   b  extend towards the peripheral edge of the disc-like rotor  32 . 
         [0040]    In the above embodiment, each pin  34  has a prism portion  34   a  formed in the intermediate portion thereof, in the longitudinal direction. The prism portions  34   a  are inserted into the rectangular holes  32   c  having the same shape, of the disc-like rotor  32 , as a result of which the pins are positioned in such a manner that the orientations of the flat portions  34   b  point in a predetermined direction. However, the cross-sectional shape of the intermediate portion of the pins  34 , in the longitudinal direction, may have a non-circular cross-sectional shape. Holes having a cross-sectional shape corresponding to that of the intermediate portion of the pins  34 , in the longitudinal direction, are formed in the disc-like rotors  32 . 
         [0041]    The disc-like rotors  32  formed as described above are fitted onto the extension  24   a  of the drive shaft  24 , with spacers  35  interposed between the disc-like rotors  32 , as illustrated in  FIG. 2 . Further, the disc-like rotors  32  are fixed to the drive shaft  24  through screwing and fastening of a bolt  37  onto the end face of the extension  24   a , interpolating a collar  36  between them. The distance between adjacent disc-like rotors  32  is adjusted means way of the thickness of the spacers  35 . 
         [0042]    A stator assembly  38  is disposed in the lower peripheral direction of the disc-like rotors  32 . As illustrated in  FIG. 1 , the stator assembly  38  comprises stators  39 ,  40 ,  41  having a semicircular arc shape that is concentric with the disc-like rotors  32  and having a triangular cross-sectional shape in the radial direction, and a holder  42  having a semi-tubular shape that is concentric with the disc-like rotors  32 . As illustrated in  FIG. 9 , the cross section of the stators  39  is shaped as an isosceles triangle. A plurality of large inner-diameter circular holes  39   a  and a plurality of small inner-diameter circular holes  39   b , being communicating to each other and concentric to each other and running from the vertex of the isosceles triangle perpendicularly to the base thereof, are disposed in the longitudinal direction of the stators  39  (respectively three in this embodiment). Circular holes  39   c  are formed perpendicular to respective circular holes  39   a . Long holes  43  are formed parallelly and equidistantly along the circular arc of the holder  42 . Band-like portions  44  for mounting the bottom face of the stators  39  are formed between the long holes  43 . Female screws  44   a  are formed in the band-like portions  44 , at positions corresponding to the circular holes  39   a ,  39   b  of the stators. As illustrated in  FIG. 10 , the stators  39  are fixed to the holder  42  by way of cap screws  47 . Circular holes  48   a  communicating with the circular holes  39   c  of the stators are formed, in the horizontal direction, in caps  48  that are shaped so as to fit onto the circular holes  39   a  of the stator. After inserting the caps  48  into the circular holes  39   a  of the stator, spring pins  49  are fixed, by insertion, to the circular holes  39   c  of the stator and to the circular holes  48   a  of the caps, whereby the circular holes  39   a  of each stator  39  become plugged. 
         [0043]    Instead of the above method, there may be formed a plurality of protrusions over the entire length of the bottom face of the stators  39 , and holes may be formed in the band-like portions  44  of the holder  42 , at positions corresponding to the protrusions, so that the protrusions of the stators  39  are inserted into the hole of the band-like portions  44 , and are welded or the like, to fix thereby the stators  39  to the holder  42 . 
         [0044]    As illustrated in  FIG. 1 , the cross-sectional shape of the stators  40 ,  41  is a right triangle. As illustrated in  FIG. 2 , one of the faces of the stator  40  that forms a right angle is fixed to the bracket  23  by way of a screw  40   a , and one of the faces of the stator  41  that forms a right angle is fixed to the side wall of the casing  31  by way of a screw  41   a.    
         [0045]    In the above embodiment, as illustrated in  FIG. 1  and  FIG. 2 , the size of the stators  40 ,  41  is larger than that of the stators  39 . Specifically, the outer diameter of the stators  40 ,  41  is substantially the same as that of the stators  39 , but the inner diameter is smaller than that of the stators  39 . The purpose of this is to allow powder and granular material that is supplied to the vicinity of the inner face of the bracket  23  and the side wall of the casing  31  to be guided quickly into a gap A, without being retained in the foregoing portions, by increasing the height of the inclined faces of the stators  40  and  41 . 
         [0046]    For the same reason, both ends of the stator  40 ,  41  are cut out obliquely downwards, as illustrated in  FIG. 1 , while both ends of the stators  39  are cut out obliquely downwards, with left-right symmetry, as illustrated in  FIG. 9 . 
         [0047]    Preferably, the stators  39  (including the cap  49 ),  40 ,  41  are formed using a material that has a smooth surface, for instance polytetrafluoroethylene (PTFE) or the like. 
         [0048]    As illustrated in  FIG. 10 , a plurality of stays  45  are standingly provided, in the peripheral direction, on one outer peripheral end face of the holder  42 . A screw insertion hole  45   a  is formed in each stay  45 . As illustrated in  FIG. 1 , female screws  23   b  are formed in the bracket  23 , at positions corresponding to the screw insertion holes  45   a . As illustrated in  FIG. 2 , the holder  42  is fixed to the bracket  23  through screwing of bolts  46 , which are inserted through the screw insertion holes  45   a , into the female screws  23   b  of the bracket  23 . 
         [0049]    In the powder and granular material crushing and sizing apparatus  1 , the stators  39  are disposed below substantially the bottom half of the disc-like rotors  32 ,  32 , between the peripheral edges of the latter. As illustrated in  FIG. 11 , a hopper-like gap portion A is delimited by the peripheral-edge disc face of the disc-like rotors  32  and the inclined face of the stators  39 . 
         [0050]    In the powder and granular material crushing and sizing apparatus  1 , powder and granular material such as wet aggregates or dry blocks, as a raw material, is charged into the casing  31  via the feeding opening  31   a , while the disc-like rotors  32  are rotating, whereupon the powder and granular material is firstly coarsely crushed by the pins  33 . The powder and granular material, having reached the gap portion A, which is an retention zone of the powder and granular material, is pushed out into the smallest gap portion B on account of the centrifugal force exerted by the rotating disc-like rotors  32 , and by the push-out force of the flat portions  34   a  of the pins  34 . From among the powder and granular material pushed out into the smallest gap portion B, those particles that match the gap setting are allowed to pass through, while particles that do not are crushed in the gap portion A, and are discharged thereafter through the smallest gap portion B into a discharge opening. 
         [0051]    To clean the disc-like rotors  32  and the stators  39 ,  40 ,  41  of the powder and granular material crushing and sizing apparatus  1 , the casing  31  is removed from the bracket  23 , and then the holder  42  is removed from the bracket  23 . Doing so exposes the peripheral edges of the disc-like rotors  32 , and the stators  39 ,  40 ,  41 , which can then be cleaned easily. 
         [0052]    To replace the disc-like rotors  32  of the powder and granular material crushing and sizing apparatus  1 , the casing  31  is removed from the bracket  23 , and then the stator assembly  38  is removed from the bracket  23 . Next, the bolt  37  and the collar  36  are removed from the drive shaft  24 , and the disc-like rotors  32  and the spacers  35  are sequentially removed from the drive shaft  24 . To complete the replacement, new disc-like rotors  32  are then inserted and fitted to the drive shaft  24 , with the spacers  35  interposed in between, and the bolt  37  is mounted to the drive shaft  24 . As described above, the disc-like rotors  32  and the spacers  35  can be precisely cleaned by being removed from the drive shaft  24 . 
         [0053]    To replace the stators  39 , the casing  31  is removed from the bracket  23 , and then the stator assembly  38  is removed from the bracket  23 . Replacement is completed by mounting the stator assembly  38 , provided with new stators  39 , onto the bracket  23 . 
         [0054]    To replace the stator  40 , the casing  31  is removed from the bracket  23 , and then the stator assembly  38  is removed from the bracket  23 . The stator  40  is removed from the bracket  23 , and then replacement is completed by mounting the new stator  40  onto the bracket  23 . 
         [0055]    To replace the stator  41 , the casing  31  is removed from the bracket  23 , the stator  41  is removed from the casing  31 , and then replacement is completed by mounting the new stator  41  onto the casing  31 . 
         [0056]    To modify the crushing and sizing particle size in the powder and granular material crushing and sizing apparatus  1 , there must be modified the smallest gap portion B between the peripheral edges of the disc-like rotors  32  and the stators  39 ,  40 ,  41 . In this case, a stator assembly  38  may be prepared in which modified stators  39  (wherein, specifically, the length of the base of the cross-sectional isosceles triangle is modified with respect to the width of the band-like portions  44 ) are disposed on the holder  42 , the width of the long holes  43  whereof is likewise modified, and stators  40 ,  41  of modified cross-sectional shape and size (modified length of the base of the cross-sectional right triangle) are prepared. The foregoing are then mounted onto the bracket  23  of the bearing housing  21  and the casing  31 . 
         [0057]    In the apparatus set forth in the above Patent document (Japanese Patent No. 4113222), a plurality of spike-shaped protrusions, arranged as two rows in the radial direction around a rotation shaft, with a predetermined spacing between protrusions both in the radial and the circumferential directions, is formed on both disc faces at the outermost peripheral edge of the discs; and also, a plurality of spike-shaped protrusions, arranged as a row along the circumferential direction with a predetermined spacing between protrusions, is formed on the faces of adapters that oppose the above disc faces in the outermost peripheral edges of the discs. Similar protrusions may also be formed in the present invention, but are not necessary if the material to be processed is a pharmaceutical product.