Abstract:
A metering feeder is provided with the following: an annular transport space formed by an outer cylinder, an inner cylinder, and a bottom plate; a central rotating blade provided on a rotating shaft in the center of the bottom plate; an outer rotating ring connected to the tip of the central rotating blade; a plurality of outer rotating blades provided on the outer rotating ring so as to point inwards; and a rotating disc in which a powder/granular-material discharge groove is formed, the top surface of said rotating disc lying in the same plane as the top surface of the bottom plate. The outer rotating blades scrape the powder/granular material in the annular-transport space into the powder/granular-material discharge groove, which transports said powder/granular material outside the outer cylinder. This metering feeder is further provided with a vertically-movable scraper for supplying large amounts of the powder/granular material and a fixed small scraper for supplying small amounts thereof. Said scrapers block the flow of the powder/granular material in the powder/granular-material discharge groove in the rotating disc and guide same to a discharge opening. This configuration makes it possible to increase the precision with which the powder/granular material is supplied.

Description:
TECHNICAL FIELD 
     The present invention relates to a metering feeder for realizing highly accurate metering supply of a powder/granular material and the like. 
     BACKGROUND OF THE INVENTION 
     Conventionally, a metering feeder for metered supply of a material such as a powder/granular material or the like as illustrated in Patent Literature 1, for example, has been developed. 
     This prior-art metering feeder has a configuration in which an inner cylinder and an outer cylinder are arranged concentrically, a gap is provided between a lower end of the inner cylinder and a bottom plate of the outer cylinder, whereby an annular transport space for a powder/granular material is provided between the inner and outer cylinders, a central rotating blade is provided on the bottom plate around a center upright rotating shaft of the bottom plate, an outer rotating ring along an inner periphery of the outer cylinder is provided at a tip end of the rotating blade, a plurality of outer rotating blades directed toward an inside are provided on the ring, a rotating disc having an upper surface on the same plane as an upper surface of the bottom plate is provided, a powder/granular-material discharge groove concentric with the disc is provided on an upper surface of the disc, the groove is disposed over an inside and outside of the outer cylinder, and a single powder/granular-material discharge scraper is fixed in the groove on an outside of the outer cylinder. 
     This metering feeder is configured such that, by rotating the central rotating blade and the rotating disc together, the powder/granular material in the annular transport space is scraped and thrown into the powder/granular-material discharge groove of the rotating disc by the outer rotating ring by means of rotation of the central rotating blade, and the powder/granular material having been thrown into the discharge groove is metered and supplied by the single powder/granular-material discharge scraper to an outside of the rotating disc. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1 Japanese Patent No. 3090555 
     SUMMARY OF THE INVENTION 
     With the prior-art metering feeder, in order to realize highly accurate supply in a batch metering of a powder/granular material, a rotating speed of the rotating disc is divided into a normal speed for rushing large supply of the powder/granular material and a low speed for making small supply of the powder/granular material in a final stage of the supply, and the rotating speed of the rotating disc in the small supply is set to a low speed so as to adjust the final supply amount in some cases. 
     However, in the prior-art metering feeder, since the single powder/granular-material discharge scraper is used, “dripping” of the powder/granular material might occur when the rotating speed of the rotating disc is lowered for the small supply. 
     Moreover, it is likely that retention of the powder/granular material occurs on a return side of the rotating disc, or if filling of the powder/granular material in the powder/granular-material discharge groove is not sufficient, supply accuracy might be affected. 
     The present invention has an object to provide a metering feeder which realizes highly accurate supply of a powder/granular material by providing a vertically-movable scraper for large supply and a fixed small scraper for small supply and by enabling the small supply of the powder/granular material only by the fixed small scraper in the small supply. 
     Moreover, the present invention has an object to provide a metering feeder which enables smooth metered supply by preventing retention of the powder/granular material by smoothly returning the powder/granular material of the rotating disc. 
     Moreover, the present invention has an object to provide a metering feeder with nigh filling efficiency of the powder/granular material after discharge by providing at recessed portion. 
     In order to achieve the above-described objects, the present invention is configured such that, 
     in a metering feeder formed by inner and outer cylinders sharing a center line, a gap is provided between a bottom plate of the outer cylinder and a lower end of the inner cylinder, an annular transport space for a powder/granular material is provided between the inner and outer cylinders, an outer rotating ring provided along an inner periphery of the outer cylinder is connected to a tip end of a central rotating blade provided on an upright rotating shaft projected at a center part of the bottom plate, a plurality of outer rotating blades directed toward an inside are provided on the outer rotating ring, a rotating disc having an upper surface on the same plane as an upper surface of the bottom plate is provided, a powder/granular-material discharge groove concentric with the disc is formed on the upper surface of the rotating disc, the powder/granular-material discharge groove supports the rotating disc on a support machine frame so that it is disposed over an inside and outside of the outer cylinder, the powder/granular material in the annular transport space is metered by the outer rotating blade and supplied to the powder/granular-material discharge groove by rotating the central rotating blade and the rotating disc in the same direction, and the powder/granular material is transported to an outside of the outer cylinder by the powder/granular-material discharge groove, the metering feeder is characterized in that a discharge opening is provided in the support machine frame on an outer side of the rotating disc outside the outer cylinder, and in the powder/granular-material discharge groove of the rotating disc, a vertically-movable scraper for large supply, fitted with the powder/granular-material discharge groove for small supply for blocking the powder/granular material in the powder/granular-material discharge groove and for guiding it to the discharge opening and a fixed small scraper for blocking a part of the powder/granular material in the discharge groove on a downstream side of the vertically-movable scraper and guiding it to the discharge opening are provided, the vertically-movable scraper being made capable of elevating between a lowered position fitted in the powder/granular-material discharge groove by elevating driving means and a raised position away from the powder/granular-material discharge groove. 
     By configuring as above, in the batch type metered supply operation, the central rotating blade and the rotating disc are rotated together, the powder/granular material is discharged while the vertically-movable scraper is positioned at the lowered position in the large supply, and when a predetermined amount of the powder/granular material has been discharged, the vertically-movable scraper is raised and then, a small supply operation is performed by the fixed small scraper, and when a target value is reached, the central rotating blade and the rotating disc are stopped so that a metered supply of the powder/granular material can be performed extremely accurately. 
     The fixed small scraper has a block portion located in the powder/granular-material discharge groove on its lower end portion and blocking a part of the powder/granular material and it is detachably provided on a scraper support portion fixed to the support machine frame, and the fixed small scraper may be provided capable of being replaced with another fixed small scraper having a block portion with a different area in the scraper support portion. 
     By configuring as above, the fixed small scrapers with different block portion areas can be used depending on a nature or a metered amount of the powder/granular material, and an extremely wide range of batch metering can be handled. 
     Outside the outer cylinder, it may be so configured that, on a downstream side of the fixed small scraper in the powder/granular-material discharge groove of the rotating disc, a loosening rod having a loosening portion for the powder/granular material on a lower end is inserted into and fixed to the powder/granular-material discharge groove from an upper surface side of the powder/granular-material discharge groove, and an upward groove is provided on a lower surface of the outer cylinder at a position where the powder/granular-material discharge groove on a return side of the rotating disc passes so that the powder/granular material loosened by the loosening rod returns from the upward groove into the annular transport space. 
     By configuring as above, the powder/granular material on the return side in the rotating disc can be smoothly returned to the annular transport space side, and retention of the powder/granular material on the return side can be effectively prevented. 
     It may be so configured that, on an outer peripheral surface of the outer rotating ring, a plurality of projections close to the inner periphery of the outer cylinder are provided, a plurality of return spaces of the powder/granular material are formed between the adjacent projections, and the powder/granular material returning into the annular transport space is filled in the return space through the upward groove and is made capable of being transported to a downstream side of the annular transport space by rotation of the central rotating blade. 
     By configuring as above, the powder/granular material having returned from the rotating disc to the annular transport space side can be filled in the return space in the outer rotating ring and transported smoothly to the downstream side, retention of the powder/granular material on the return side can be prevented, and each projection levels the powder/granular material in the powder/granular-material discharge groove of the rotating disc, whereby filling efficiency can be improved. 
     It may be so configured that, by hollowing out a ring shape in an inner surface on an outer periphery side of the powder/granular-material discharge groove of the rotating disc, a recessed portion made of a ring-shaped small groove having a certain width is formed and configured such that the vertically-movable scraper is not located in the recessed portion in lowering of the vertically-movable scraper, but only the powder/granular material in the recessed portion passes the vertically-movable scraper and is transported to the downstream side, the fixed small scraper is configured such that the powder/granular material located on an upper side from the powder/granular material of the recessed portion is discharged, whereby the powder/granular material in the recessed portion is not discharged but remains, and the powder/granular material to be subsequently discharged onto the powder/granular material in the recessed portion is filled on the downstream side from the fixed small scraper. 
     By configuring as above, since the powder/granular material to be newly discharged is filled on the powder/granular material remaining in the recessed portion, the powder/granular material into the powder/granular-material discharge groove on the return side can be easily filled, whereby filling efficiency of the powder/granular material can be improved. 
     Since the present invention is configured as above, in the batch type metered supply operation, the powder/granular material is discharged while the vertically-movable scraper is positioned at the lowered position in the large supply, and when a predetermined amount of the powder/granular material has been discharged, the vertically-movable scraper is raised and then, the small supply operation is performed by the fixed small scraper, and when the target value is reached, an operation such as stop of the central rotating blade and the rotating disc can be performed so that a metered supply of the powder/granular material can be performed extremely accurately. 
     Moreover, the fixed small scrapers with different block portion areas can be used depending on the nature or the metered amount of the powder/granular material, and an extremely wide range of batch metering can be handled. 
     Moreover, the powder/granular material on the return side in the rotating disc can be smoothly returned to the annular transport space, and retention of the powder/granular material on the return side can be effectively prevented. 
     Moreover, the powder/granular material having been returned from the rotating disc to the annular transport space side can be filled in the return space on the outer rotating ring and can be smoothly transported to the downstream side, whereby retention of the powder/granular material on the return side can be prevented, and each of the projections can level the powder/granular material in the powder/granular-material discharge groove of the rotating disc, whereby filling efficiency can be improved. 
     Moreover, since the powder/granular material to be newly discharged is filled on the powder/granular material remaining in the recessed portion, the powder/granular material can be easily filled into the powder/granular-material discharge groove on the return side, whereby filing efficiency of the powder/granular material can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side sectional view of a metering feeder according to the present invention. 
         FIG. 2  is an X-X line sectional view of  FIG. 1 . 
         FIG. 3  is a cross sectional view of a vicinity of a rotating disc of the metering feeder. 
         FIG. 4  is an enlarged sectional view of the vicinity of the rotating disc of the metering feeder. 
         FIG. 5  is an enlarged sectional view of the vicinity of the rotating disc of the metering feeder. 
         FIG. 6  is a Y-Y line sectional view of  FIG. 5 . 
         FIG. 7  is an enlarged sectional view of the vicinity of the rotating disc of the metering feeder. 
         FIG. 8  is a Z-Z line sectional view of  FIG. 7 . 
         FIG. 9A  is a side view of a vicinity of a scraper of the metering feeder, and  FIG. 9B  is a side view of a vicinity of a vertically-movable scraper. 
         FIG. 10A  is a side view of the vicinity of the scraper of the metering feeder, and  FIG. 10B  is a side view of a vicinity of a fixed small scraper. 
         FIG. 11  is an enlarged view of the vicinity of the fixed small scraper to  FIG. 10B . 
         FIG. 12  is a sectional view of a vicinity of a loosening rod of the metering feeder. 
         FIG. 13  is an enlarged view of the vicinity of the loosening rod in  FIG. 12 . 
         FIG. 14A to 14E  illustrate the fixed small scraper used in the metering feeder. 
         FIG. 15  is a block diagram illustrating an electric configuration of a control system in the metering feeder. 
         FIG. 16A  is an enlarged sectional view of a vicinity of a recessed portion of the rotating disc of the metering feeder, and  FIG. 16B  is an enlarged sectional view of the rotating disc in which the recessed portion is not present. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A metering feeder according to the present invention will be described below in detail. 
     As illustrated, in  FIGS. 1 and 2 , upright circular inner and outer cylinders  1  and  2  sharing a center line C are provided integrally by a flange  3 , and a bottom plate  4  is provided on the outer cylinder  2 . A slight gap t is interposed between this bottom plate  4  and a lower end of the inner cylinder  1 , an annular transport space  5  for a powder/granular material is formed between the inner and outer cylinders  1  and  2 , and an upper end of an upright rotating shaft  6  is projected on the center line C of true bottom plate  4 . 
     Base portions of a plurality (four pieces) of spoke-shaped central rotating blades  7  in contact with an upper surface of the bottom plate  4  are provided on the upright rotating shaft  6 , a tip end of the rotating blade  7  is connected to an outer rotating ring  8  close to an inner peripheral surface of the outer cylinder  2  through the gap t, and a plurality of short outer rotating blades  9  in contact with the upper surface of the bottom plate  4  and directed toward an inside are provided on the ring  8  (see  FIG. 2 ). As described above, the central rotating blade can be constituted by the spoke-shaped central rotating blade  7 , for example. 
     On an outer periphery of the rotating ring  3 , a plurality of projections  8   a  close to the inner peripheral surface of the outer cylinder  2  through an extremely slight gap is provided at an interval of a certain angle so that an upper surface of a powder/granular material e having returned by a rotating disc  10  which will be described later can be leveled. 
     A driving shaft  20  is provided on a lower part of the upright rotating shaft  6  of the bottom plate  4 , a variable speed motor  22  by an inverter or the like is provided on the driving shaft  20  through a speed reducer  21 , and the spoke-shaped central rotating blade  7  is made rotatable by the variable speed motor  22  horizontally in an arrow A direction. 
     On the bottom plate  4  constituted as above, the rotating disc  10  having an upper surface  10   a  on the same plane with the upper surface thereof or an upper end  10   b  of the outer periphery and extending over the inside and outside of the outer cylinder  2  is provided, a rectangular support device  11  supporting the rotating disc  10  at a position in the same plane rotatably on an outer peripheral side of the disc  10  is joined to a lower surface of the bottom plate  4  by a bolt  12 , and a rectangular discharge opening  13  is opened on an outer side (the side opposite to the inner cylinder  1 ) of the device  11 . To this discharge opening  13 , a discharge chute  13   a  is connected downwardly as illustrated in  FIG. 1 . As described above, a support machine frame can be constituted by the rectangular support device  11 , for example. 
     This support device  11  has the driving shaft  14  on the lower part of the rotating disc  10  as illustrated in  FIG. 1 , rotates the rotating disc  10  around the driving shaft  14  (rotation center C′) horizontally in an arrow B direction and has a variable speed motor  16  by an inverter or the like provided through a speed reducer  15 . A rotating direction (arrow A direction) of the central rotating blade  7  and a rotation direction (arrow B direction) of the rotating disc  10  are assumed to be the “same direction” with respect to each of the rotation centers C and C′. Therefore, in rotation in this “same direction”, the rotating directions of the central rotating blade  7  and the rotating disc  10  are “opposite directions” in an overlapped part between the central rotating blade  7  and the rotating disc  10 . 
     In the upper surface of the rotating disc  10 , a ring-shaped powder/granular-material discharge groove  17  having a recessed shape concentric with the disc  10  is formed, and as its vertical section, the one illustrated in  FIG. 4 , for example, is used. That is, the vertical section is composed of a bottom surface  17   a  on an innermost peripheral side forming the bottom of the powder/granular-material discharge groove  17 , an inclined portion  17   b  forming an inclined surface inclined linearly upward from an outer peripheral edge of the bottom surface  17   a  toward the upper end  10   b  of the outer periphery of the rotating disc  10 , and a recessed portion  17   c  constituted so as to hollow out a surface (inner surface) of the inclined portion  17   b  downward on a certain width on an inner peripheral side from the upper end  10   b  forming an outermost peripheral edge of the rotating disc  10  (see  FIG. 3 ). 
     That is, by hollowing out a ring shape in the inner surface on the outer peripheral side of the powder/granular-material discharge groove  17  of the rotating disc  10 , the recessed portion  17   c  made of a small groove  24  having a ring shape (concentric with the rotating disc) with a certain width is formed. 
     Then, the powder/granular material supplied into the inner cylinder flows out into the annular transport space  5  from the gap t by rotation of the rotating blade  7 , conveyed by the central rotating blade  7  and the outer rotating blade  9  in an arrow h direction in the space  5 , dropped and supplied into the powder/granular-material discharge groove  17  of the disc  10  at a portion of the rotating disc  10 , filled and supplied into the discharge groove  17  by the rotation of the rotating disc  10  in an arrow B direction in a state in which the upper surface thereof is scraped by the lower surface of the outer cylinder  2  and the outer rotating blade  9 , and enters a state in which the powder/granular material e is filled and supplied closely to a position T at the same level with the upper surface  10   a  of the rotating disc  10  as illustrated by hatching in  FIG. 4  and  FIG. 10B  in the powder/granular-material discharge groove  17  going out of the outer cylinder  2 . 
     Here, the position of the lower surface of the outer cylinder  2 , the upper surface  10   a  of the rotating disc  10 , and the position of the upper end  10   b  axe on substantially the same level, and the lower surfaces of the outer rotating ring  8 , the projection  8   a , and the outer rotating blade  9  are on substantially the same level position as the upper surface  10   a  and the upper end  10   b.    
     The recessed portion  17   c  is made of, as illustrated in  FIG. 4 , a horizontal portion  17   c ′ formed in an outer peripheral direction from the position of the inclined portion  17   b  on the outer peripheral side and an inclined portion  17   c ″ forming a steep upward inclined surface from the horizontal portion  17   c ′ toward the upper end  10   b  and is formed so as to constitute a ring-shaped small groove  24  having a substantially triangular vertical section by a virtual line P connecting the inclined portion  17   b  and the upper end  10   b  or the vicinity of the upper end  10   b , the horizontal portion  17   c ′, and the inclined portion  17   c″.    
     Here, an upstream side and a downstream side are defined on the basis of the rotating directions of the spoke-shaped central rotating blade  7  and the rotating disc  10 . Moreover, an area from after discharge of the powder/granular material to the discharge opening  13  a fixed small scraper  19  in the rotating disc  10  to the annular transport space  5  is referred to as a return side. 
     On an outer side of the outer cylinder  2 , a vertically-movable scraper  18  for large quantity discharge (for large supply) of the powder/granular material to be inserted into the groove  17  is provided at a position corresponding to the discharge opening  13  and the fixed small scraper  19  for small quantity discharge (for small supply) of the powder/granular material is provided on the downstream side of the vertically-movable scraper  18 , and it is configured such that, by inserting these scrapers  18  and  19  into the groove  17 , the powder/granular material e in the groove  17  can be guided and discharged into the discharge opening  13  (see arrows E and F in  FIG. 3 ). 
     The vertically-movable scraper  18  is made of a plate shaped body with a small plate thickness as illustrated in  FIGS. 9A and 9B , and its lower edge has a shape fitted with a vertical sectional shape of the powder/granular-material discharge groove  17  when it is inserted into the powder/granular-material discharge groove  17  with diagonal inclination in a direction of the discharge opening  13  from the upstream side toward the downstream side as illustrated in  FIG. 3 , that is, has a horizontal portion  18   a  fitted with the bottom surface  17   a  and an inclined portion  18   b  fitted with the inclined portion  17   b  as illustrated in  FIG. 9B , and an engagement portion  18   c  to be engaged with the outer peripheral surface side of the rotating disc  10  for positioning the scraper  18  with respect to the rotating disc  10  is formed downward on an upper end portion of the inclined portion  18   b . Since the inclined portion  18   b  of the scraper  18  is in a linear state, when the scraper  18  is fitted with the powder/granular-material discharge groove  17 , the recessed portion  17   c  is in a state in which a space is formed. That is, when the vertically-movable scraper  18  is lowered, it is configured such that the vertically-movable scraper  18  is not located in the recessed portion  17   c  but only a powder/granular material e′ in the recessed portion  17   c  passes the vertically-movable scraper  18  and is transported to the downstream side. 
     An inclination angle of the vertically-movable scraper  18  is in a state in which an end portion on the discharge opening  13  side is inclined toward the downstream side by an angle of θ1 degrees around a center Q 1  with respect to a radius line N 1  in its width direction and a surface for blocking the powder/granular material is directed toward the discharge opening  13  side as illustrated in  FIG. 3 . 
     This vertically-movable scraper  18  (see  FIG. 9 ) is fixed to the support portion  34  by bolts D and D vertically downward. A support rod  34 ′ is connected and fixed to an upper edge of the support portion  34 , an upper end portion of the support rod  34 ′ is located on an upper surface side of a housing  35  through an opening  35   a ′ formed in an upper surface plate  35   a  of the housing  35  covering an upper part of the rectangular support device  11 , and an upper end portion of the support rod  34 ′ at this position is connected to a vertical elevating driving shaft  33   a  of an air cylinder  33  fixed vertically to the upper surface plate  35   a . As described above, the elevating driving means can be constituted by the support portion  34 , the support rod  34 ′, the vertical elevating driving shaft  33   a , the air cylinder  33  and the like. 
     When the elevating driving shaft  33   a  of the air cylinder  33  is raised, the scraper  18  is located at a raised position P 1  (position in  FIG. 10A ) in  FIG. 6 , that is, at the raised position P 1  where a lower end of the scraper  18  is located above the upper surface  10   a  of the rotating disc  10 . That is, the position is separated upward away from the powder/granular-material discharge groove  17 . 
     When the elevating driving shaft  33   a  of the air cylinder  33  is lowered, the scraper  18  is configured to be located at a lowered position P 2  in  FIG. 6 , that is, in a state in which the horizontal portion  18   a  and the inclined portion  18   b  of the scraper  18  are fitted with the bottom surface  17   a  and the inclined portion  17   b  of the powder/granular-material discharge groove  17  (states in  FIGS. 9A and 9B ). 
     Therefore, the scraper  18  does not discharge the powder/granular material e supplied to the powder/granular-material discharge groove  17  at the raised position P 1  (see  FIG. 10 ), while at the lowered position P 2  (see  FIG. 9 ), the scraper  18  is fitted with the powder/granular-material discharge groove  17  to the bottom surface  17   a  so as to close the discharge groove  17 , whereby the powder/granular material e supplied to the discharge groove  17  is guided by the scraper  18  to the direction of the rectangular discharge opening  13  and is discharged to the discharge opening  13  (see the arrow E in  FIG. 3 ). As described above, the discharge opening can be constituted by the rectangular discharge opening  13 . 
     At this time, since the vertically-movable scraper  18  is not located in the recessed portion  17   c , the powder/granular material e′ remains in the recessed portion  17   c  (see  FIGS. 9B and 13 ) and moves (passes) to the downstream side as it is with the rotation of the rotating disc  10 . 
     The fixed small scraper  19  is constituted by a thin plate shaped body similar to the vertically-movable scraper  13  as illustrated in  FIG. 10 , and is provided with inclination toward the discharge opening  13  side to the downstream side from the upstream side of the powder/granular material on the downstream side of the vertically-movable scraper  18  as illustrated in  FIG. 3 . This fixed small scraper  19  is fixed to a scraper support portion  23  vertically downward by the bolts D and D, and the scraper support portion  23  has its upper end fixed to the upper surface plate  35   a  of the housing  35  (support machine frame) by the bolts D and D. 
     This fixed small scraper  19  has its lower end constituted by a horizontal portion  19   a  and a downward projecting portion  19   b  provided on an outer side of the horizontal portion  19   a  as illustrated in  FIG. 10B , and the downward projecting portion  19   b  is located in correspondence with the recessed portion  17   c  and is constituted by a powder/granular-material block plate portion  19   b ′ slightly going into the powder/granular-material discharge groove  17  from the position T at the level for the upper end  10   b  of the rotating disc  10  and an engagement portion  19   b ″ engaged with the outer peripheral surface of the rotating disc  10  as illustrated in  FIG. 11 . 
     The powder/granular-material block plate portion  19   b ′ of the downward projecting portion  19   b  forms a substantially triangular block portion  31  in which an upward inclined surface  30  is formed in a direction of the engagement portion  19   b ″ from a lowest end on a side of the horizontal portion  19   a , and in the block portion  31 , a part of the powder/granular material in the powder/granular-material discharge groove  17 , moving in the arrow B direction, is blocked, and a small amount of the blocked powder/granular material is guided and discharged to the direction of the discharge opening  13  (see the arrow F in  FIG. 3 ). Moreover, the inclined surface  30  is provided along the virtual line F on the recessed portion  17   c.    
     Regarding this fixed small scraper  19 , those having various shapes as illustrated in  FIGS. 14A to 14E  can be used by replacement, and any one of them indicates an upper surface level of the powder/granular material e in the powder/granular-material discharge groove  17  of the rotating disc  10  at the position T in the figure. Therefore, the powder/granular material can be blocked by the powder/granular-material block plate portion  19   b ′ (block portion  31 ) located below the position T and guided to the direction of the discharge opening  13 . Specifically, a portion indicated by hatching in  FIG. 14  is the block portion  31  capable of discharging the powder/granular material, and from the scraper  19  having the block portion  31  with the smallest area in  FIG. 14E  to the scraper  19  having the block portion  31  with the largest area in  FIG. 14A  are illustrated in order of the area of the block portion  31  from the smallest to the largest. Any one of the block portions  31  is located above the recessed portion  17   c  and is configured so that the powder/granular material located above the powder/granular material in the recessed portion  17   c  is discharged and the powder/granular material in the recessed portion  17   c  remains without being discharged. The fixed small scraper  19  in  FIG. 14A  does not have the horizontal portion  19   a  but has the block portion  31  formed to the other end. 
     The fixed small scraper  19  is detachably provided by the bolt D on the scraper support portion  23  fixed to the housing  35 , and the fixed small scraper  19  can be replaced with another fixed small scraper  19  having the block portion  31  with a different area in the scraper support portion  23 . 
     In the batch type metering, regarding this fixed small scraper  19 , a large quantity of the powder/granular material is guided by the vertically-movable scraper  18  to the discharge opening  13  in the large supply, and the vertically-movable scraper  18  is raised to the raised position P 1  in the small supply stage and then, the small amount of the powder/granular material (the powder/granular material e″ in  FIGS. 10A and 16A , the small amount of the powder/granular material corresponding to the area of the block portion  31  (a part of the powder/granular material)) is discharged by the block portion  31  of the fixed small scraper  19  so that metering accuracy of the batch metering is improved. As illustrated in  FIGS. 14A to 14E , the amount of the small supply can be adjusted by the area of the powder/granular-material block plate portion  19   b ′ (block portion  31 ) of the fixed small scraper  19  such that the small supply in the smallest amount can be made by the fixed small scraper  19  in  FIG. 14E  and the small supply in the largest amount can be made by the fixed small scraper  19  in  FIG. 14A . 
     The inclination angle of the fixed small scraper  19  is in a state in which the end portion on the discharge opening  13  side is inclined toward the downstream side by an angle of θ2 degrees around a center Q 2  with respect to a radius line N 2  in its width direction and a surface for blocking the powder/granular material is directed toward the discharge opening  13  side as illustrated in  FIG. 3 . 
     A loosening rod  25  is provided on the downstream side from the fixed small scraper  19  in the powder/granular-material discharge groove  17  of the rotating disc  10 . This loosening rod  25  is formed of a rod-shaped member, has its upper end portion retained and fixed by a nut N on the upper surface plate  35   a  of the housing  35  as illustrated in  FIG. 12 , while the lower end portion thereof is linearly extended vertically downward to the vicinity of the bottom surface  17   a  of the discharge groove  17 , and the loosening portion  25   a  having a J-shape bent upward along the inclination portion  17   b  of the discharge groove  17  is formed from the lower end portion. Moreover, as illustrated in  FIG. 3 , it is fixed in a state inclined to the downstream side by an angle of θ3 degrees around a center Q 3  of the loosening rod  25  with respect to a radius line N 3  on a plan view. 
     This loosening rod  25  has a function of loosening the powder/granular material remaining in the powder/granular-material discharge groove  17  with rotation of the rotating disc  10  and returning to the annular transport space  5  and it is configured such that the returning powder/granular material e is loosened by presence of the loosening rod  25  as illustrated in  FIG. 13  so as to form a raised portion R, whereby the powder/granular material e′ (hatched portion in  FIG. 13 ) can be reliably filled in the portion of the small groove  24  in the recessed portion  17   c  (see  FIG. 13 ). 
     On the lower surface of the outer cylinder  2  on the return side after the powder/granular material of the rotating disc  10  has been discharged, a gate-shaped upward groove  26  having a vertical width K and a width L in a circumferential direction within a range from the upper end  10   b  of the outer periphery of the rotating disc  10  to the upper surface  10   a  is provided (see  FIGS. 3 and 13 ). This upward groove  26  is to enable smooth return of the powder/granular material forming the raised portion R raised by the loosening rod  25  into the outer cylinder  2  through the upward groove  26 . 
     The powder/granular material e having returned into the annular transport space  5  through the upward groove  26  is filled in a return space S between the projection  8   a  of the outer rotating ring  8  and the projection  8   a  (see  FIG. 3 ) and can be smoothly transported to the downstream side in the annular transport space  5  by rotation of the central rotating blade  7  in the arrow A direction, whereby retention of the powder/granular material on the return side in the vicinity of the upward groove  26  can be prevented, and the projection  8   a  is configured to be able to level the upper surface of the powder/granular material having returned into the powder/granular-material discharge groove  17 . 
       FIG. 15  is a block diagram illustrating an electric configuration of the metering feeder according to the present invention, in which reference numeral  37  denotes a metering feeder body, the body  37  being placed on a support base  32  through a column  36 . This support base  32  has a function of a platform scale and is configured capable of metering a weight of the entire powder/granular material input into the inner cylinder  1 . A controller  38  receives a metering signal which is a metered value of the platform scale at all times. In the controller  38 , a target value Hg which is a metered value of the powder/granular material and a proximate value Gg (H&gt;G) which is a metered value at timing when the large supply is changed to the small supply and is slightly smaller than the target value are set in advance in the batch type metering. 
     Then, the controller  38  drives the variable speed motors  22  and  16  at a certain speed in the large supply so as to rotate the central rotating blade  7  and the rotating disc  19  at a certain speed so as to discharge the powder/granular material from the discharge opening  13  through the discharge chute  13   a  in a state in which the air cylinder  33  is lowered and the vertically-movable scraper  18  is located at the lowered position P 2 . 
     The controller  38  recognizes the discharge amount of the powder/granular-material discharged from the discharge chute  13   a  as a metered value of the powder/granular material on the basis of the metering signal from the platform scale, and when it detects that the metered value reaches the proximate value Gg, it raises the air cylinder  33  and positions the vertically-movable scraper  18  to the raised position P 1  and then, lowers the speed of the variable speed motor  16  (a certain speed at ½ to ⅓ of the speed in the large supply, for example), whereby the rotating speed of the rotating disc  10  is lowered and transition is made to the small supply operation, and the small supply operation is performed by the fixed small scraper  19 . Alternatively, the small supply operation is performed by the fixed small scraper  19  at the same speed as that in the large supply without lowering the rotating speed of the rotating disc  10 . 
     In the small supply operation, such control is configured to be executed that, when the metered value (discharge amount of the powder/granular material) has reached the target value Hg on the basis of the metering signal, rotation of the variable speed motors  16  and  22  is stopped. 
     Since the present invention is configured as described above, an operation of the metering feeder of the present invention will be described below. Here, it is assumed that the vertically-movable scraper  18  is first located at the lowered position P 2 , moreover, it is assumed that the powder/granular material is a powder/granular material such as “soybean flour” or the like, for example, and the batch type metering of the powder/granular material (target value Hg, proximate value Gg) is to be performed. An accommodating bag or the like for the powder/granular material is installed on a lower end of the discharge chute  13   a  of the discharge opening  13 . It is also assumed that the fixed small scraper illustrated in  FIG. 14E  is used as the fixed small scraper  19 . 
     First, the powder/granular material (powdery food material such as a soybean flour, for example) is accommodated in the inner cylinder  1 . After that, the variable speed motor  22  is driven at the certain speed. Thus, the spoke-shaped central rotating blade  7  and the outer rotating blade  9  are rotated at the certain speed in the arrow A direction. At the same time, the variable speed motor  16  is driven at the certain speed. Thus, the rotating disc  10  is also rotated at the certain speed in the arrow B direction. 
     Then, the powder/granular material in the inner cylinder  1  flows out to the annular transport space  5  side from substantially the entire periphery of the gap t by rotation of the spoke-shaped central rotating blade  7 , and the powder/granular material having flowed out to the annular transport space  5  is transported in the transport space  5  by the plurality of outer rotating blade  9  in the arrow A direction. 
     The powder/granular material is conveyed in the annular transport space  5  in the arrow A direction by an end edge of the cuter rotating blade  9  on a side of an advancing direction and at the position of the rotating disc  10 , it is sequentially dropped and supplied into the powder/granular-material discharge groove  17  of the disc  10  from above the bottom surface  4 . 
     Since the rotating disc  10  is rotating in the arrow B direction, the powder/granular material dropped and supplied into the powder/granular-material discharge groove  17  has its upper surface scraped by the edge of the outer rotating blade  9  on the advancing direction side and on the lower surface of the outer cylinder  2  by rotation in the arrow B direction and is transported to the outer side of the outer cylinder  2  in a state with the upper surface of the powder/granular material in the groove  17  horizontally scraped at the same level as the position T substantially the same as the upper surface  10   a  of the rotating disc  10 . 
     That is, in the powder/granular-material discharge groove  17 , the powder/granular material e is filled in each of the bottom surface  17   a , the inclined portion  17   b , and the recessed portion  17   c , has the upper surface forming a horizontal surface at the position T, and is transported in the arrow B direction outside the outer cylinder  2  on the basis of the rotation of the rotating disc  10  in a state closely filled in the entire discharge groove  17  (see  FIG. 4 ). 
     The powder/granular material remaining in the annular transport space  5  by being scraped in the space  5  is transported in the arrow A direction by the outer rotating blade  9  and is dropped and filled in the powder/granular-material discharge groove  17  on the return side after discharge of the powder/granular material of the rotating disc  10 , and the remaining powder/granular material not filled in the discharge groove  17  repeats the operation of rotation and transport in the arrow A direction by the outer rotating blade  9  in the annular transport space  5 , and the powder/granular material in the annular transport space  5  is not compacted. 
     Then, the powder/granular material having been transported by the rotating disc  10  to substantially the center part of the powder/granular-material discharge opening  13  is blocked by the plate surface of the vertically-movable scraper  18  arranged with inclination except the recessed portion  17   c  (see  FIGS. 9A and 9B ), and the blocked powder/granular material e flows out to the outside from inside the discharge groove  17  in the arrow E direction along the scraper  18 , and thus, the powder/granular material e continuously flows out in the arrow E direction and is discharged to the outside from the powder/granular-material discharge opening  13  (large supply operation (see  FIG. 3 )). 
     Such operation is an operation in the “large supply”, and the powder/granular material in the powder/granular-material discharge groove  17  blocked by the scraper  18  is discharged to the powder/granular-material discharge opening  13 . At this time, the powder/granular material e′ in the small groove  24  in the recessed portion  17   c  is not discharged but passes as it is and is transported to the downstream side (see  FIG. 9A ). Moreover, there is no powder/granular material blocked by the fixed small scraper  19  at this time, and the loosening rod  25  is not functioning. 
     In this large supply operation, the controller  38  recognizes the discharge amount of the powder/granular material as the metered value on the basis of the metering signal from the platform scale, and when the metered value has reached the proximate value Gg, the controller  38  drives the air cylinder  33  so as to raise the vertically-movable scraper  18  to the raised position P 1 . At the same time, the controller  33  lowers the rotating speed of the variable speed motor  16  to a certain speed at ⅓, for example, and rotates the rotating disc  10  more slowly than that in the large supply. 
     Then, the powder/granular material e having been blocked by the vertically-movable scraper  18  is transported to the downstream side, and thus, the powder/granular material e in the state filled to the position T in the powder/granular-material discharge groove  17  is transported toward the fixed small scraper  19  on the downstream side (see  FIGS. 10A and 10B ). 
     Then, the powder/granular material having been transported from the position of the vertically-movable scraper  13  to the downstream side is blocked by the block portion  31  of the powder/granular material fixed small scraper  19 , and a small amount of the powder/granular material e″ in the amount blocked by the block portion  31 , that is, the powder/granular material e″ blocked in correspondence with the area of the block portion  31  is guided and discharged in the arrow F direction (see  FIG. 10A ) and is supplied and discharged into the discharge opening  13  along the arrow F (see  FIG. 3 ). 
     At this time, the controller  38  recognizes the discharge amount of the powder/granular material as the metered value on the basis of the metering signal from the platform scale and detects whether or not the metered value has reached the target value Hg. Then, at a point of time when the metered value has reached the target value Hg, the controller  38  stops the variable speed motors  16  and  22 . 
     As a result, an accurate amount (target value Hg) of the powder/granular material can be supplied to the discharge opening  13  and into the accommodating bag on the lower end of the discharge chute  13   a . In the small supply operation, since the small amount of the powder/granular material can be discharged by the block portion  31  of the fixed small scraper  19  as described above, the “dripping” or the like of the powder/granular material does not occur even if the rotation of the rotating disc  10  is stopped, and accurate batch metering can be made. 
     The discharge amount of the powder/granular material in the small supply can be changed by replacing the fixed small scraper  19 . That is, the discharge amount in the small supply is determined by the area of the block portion  31  of the fixed small scraper  19 , and thus, by setting the various fixed small scrapers  19  on the support portion  23  as illustrated in  FIG. 14 , the discharge amount of the powder/granular material in the small supply can be changed, whereby a wide range of a metering operation can be performed. Specifically, the bolts D and D of the scraper support portion  23  are removed so as to remove the fixed small scraper  19 , and another fixed small scraper  19  is fixed to the scraper support portion  23  by the bolts D and D. 
     In such small supply operation, the powder/granular material in the powder/granular-material discharge groove  17  other than the powder/granular-material e″ (see  FIG. 16A ) blocked and discharged by the fixed small scraper  19  is further transported together with the powder/granular material e′ remaining in the recessed portion  17   c  to the downstream side from the scraper  19 , stirred by the loosening portion  25   a  at the lower end of the loosening rod  25 , the raised portion R is formed by being loosened, and the powder/granular material is also filled onto the small groove  24  of the recessed portion  17   c  at the same time (see  FIG. 13 ). 
     As described above, the powder/granular material e′ is reliably filled in the upper part of the small groove  24  of the recessed portion  17   c  by the loosening rod  25 , and when the rotating disc  10  is transported to the annular transport space  5 , the powder/granular material e to be newly discharged can be reliably filled in the upper part of the powder/granular material e′ filled in the small groove  24  (upper side of the virtual line P in  FIG. 16A ), whereby filing efficiency of the powder/granular material on the upper part side of the recessed portion  17   c  can be improved. 
     When the return side of the rotating disc  10  returns to the annular transport space  5  through the upward groove  26 , the powder/granular material e′ has been already filled in the small groove  24  of the recessed portion  17   c  reliably (see  FIGS. 13 and 16A ) and thus, in the annular transport space  5 , it is only necessary that the powder/granular material having been transported by the cater rotating blade  9  and the like is dropped and supplied onto the powder/granular material e′. That is, in the annular transport space  5  on the return side, the powder/granular material e to be newly discharged is dropped and supplied onto the powder/granular material e′ in the small groove  24  and is scraped by the cuter rotating blade  9  and the lower surface of the outer cylinder  2  with rotation of the rotating disc  10  in the arrow B direction and as a result, when the rotating disc  10  is transported to the outside of the outer cylinder  2 , the powder/granular material can be reliably filled on the recessed portion  17   c  to the position T at the same level as the upper surface  10   a  of the rotating disc  10  (see the powder/granular material e in  FIGS. 6 and 16A ). 
     Here, a case in which the recessed portion  17  of the powder/granular-material discharge groove  17  is not present, the powder/granular material of the inclined portion  17   b  in the vicinity of the outer peripheral edge in the powder/granular-material discharge groove  17  is discharged by the block portion  31  of the fixed small scraper  19 , and the surface (metal surface M) of the inclined portion  17   b  at the position corresponding to the block portion  31  is exposed ( FIG. 16B ) will be examined. In this case, on the return side, the powder/granular material needs to be filled directly on the metal surface M where no powder/granular material of the inclined portion  17   b  of the powder/granular-material discharge groove  17  is present, but by further filling the powder/granular material on the powder/granular material e′ filled in the recessed portion  17   c  rather than by directly supplying the powder/granular material to the metal surface M, the powder/granular material can be filled more easily, and filling efficiency of the powder/granular material can be improved. This is considered to be caused by the fact that a friction coefficient between the powder/granular material and the powder/granular material is larger than the friction coefficient between the metal and the powder/granular material (see  FIG. 16A ). 
     As a result, particularly, a sufficient amount of the powder/granular material can be filled to the position T at all times in the vicinity of the outer peripheral edge in the powder/granular-material discharge groove  17  of the rotating disc  10  corresponding to the block portion  31  of the fixed email scraper  19 , whereby discharge accuracy of the powder/granular material by the block portion  31  of the fixed small scraper  19  in the small supply can be improved. 
     Then, the powder/granular material in which the raised portion R has been formed is transported to the downstream side by rotation of the rotating disc  10  in the arrow B direction and is smoothly transported to the annular transport space  5  side through the up ware groove  26  of the outer cylinder  2 . 
     At this time, since the projection  8   a  of the outer rotating ring  8  is transported in the arrow A direction, the powder/granular material e having been transported from the upward groove  26  to the annular transport space a side enters into the return space S between the projection  8   a  and the projection  8   a  and is smoothly transported in the arrow A direction, that is, to the downstream side. As a result, the powder/granular material is not retained in the vicinity of the upward groove  26  (return portion) but the powder/granular material e can be smoothly returned to the annular transport space  5  side. 
     The powder/granular material e having entered in the return space S is transported to the downstream side but can make a circle in the annular transport space S and can be supplied again into the powder/granular-material discharge groove  17  at the position of the rotating disc  10 , and this operation is repeated. 
     Moreover, since each of the projections  8   a  of the outer rotating ring  8  crosses above the position T on the upper surface of the powder/granular-material discharge groove  17 , the powder/granular material on the upper surface of the discharge groove  17  can be leveled, and the powder/granular material of the raised portion R can be also filled on the upper part of the recessed portion  17   c  efficiency by the projections  8   a.    
     In the above-described embodiment, the rotating speed of the rotating disc  10  in the small supply is made lower than that in the large supply, but the speed of the rotating disc  10  may be the same speed as that in the large supply without lowering the speed in the small supply. In this case, too, as compared with the large supply by the vertically-movable scraper  18 , a small amount of the powder/granular material can be supplied and discharged by the block portion  31  of the fixed small scraper  13  in the small supply and thus, accurate batch metering can be made even if the speed of hire rotating disc  10  is made the same speed as that in the large supply. 
     As an example, a target value was metered with a sampling time of 10 seconds by using the fixed small scraper  19  in  FIG. 14E , the “soybean flour” as the powder/granular material, the rotating speed 6 [r/min] of the variable speed motor  22 , the rotating speed of the variable speed motor  16  at 28 [r/min] in the large supply and 9 [r/min] in the small supply, the target value H=50 g, and the proximate value G=19 g. As a result, the metered value could be accommodated within a range from 50.11 g to 50.24 g with respect to the target value of 50 g. 
     Moreover, substantially the same metering accuracy could be obtained even if the rotating speed of the variable speed motor  16  is set at the same speed of 28 [r/min] for both in the large supply and the small supply under the same condition as above. 
     In the present invention, as described above, in the batch type metered supply operation, the powder/granular material is discharged in the state in which the vertically-movable scraper  18  is located at the lowered position P 2  in the large supply and at the time when the predetermined amount of the powder/granular material has been discharged, the vertically-movable scraper  18  is raised, and after that, the small supply operation is performed by the fixed small scraper  19 , and when the target value Hg is reached, the operation such as stopping of the central rotating blade  7  and the rotating disc  10  can be performed, whereby metered supply of the powder/granular material can be made extremely accurately. 
     Moreover, by lowering the rotating speed of the rotating disc in the small supply, more accurate batch type metered supply can be performed. Moreover, even if the rotating speed of the rotating disc in the small supply is set to the same speed as that in the large supply without lowering the rotating speed of the rotating disc, accurate batch type metered supply can be performed by making the small supply by the fixed small scraper  19  in the small supply. 
     Moreover, the fixed small scrapers  19  with different areas of the block portions  31  can be used depending on the nature or the metered value of the powder/granular material, and an extremely wide range of the batch metering can be handled. 
     Moreover, the powder/granular material on the return side in the rotating disc  10  can be smoothly returned to the annular transport space  5  side, and retention of the powder/granular material on the return side can be prevented. 
     Moreover, the powder/granular material having returned to the annular transport space  5  side from the rotating disc  10  can be filled in the return space S in the outer rotating ring  8  and can be smoothly transported to the downstream side, and retention of the powder/granular material on the return side can be prevented, and each of the projections  8   a  can level the powder/granular material in the powder/granular-material discharge groove  17  of the rotating disc  10  and improve filling efficiency. 
     Moreover, since the powder/granular material to be newly discharged is filled on the powder/granular material remaining in the recessed, portion  17   c , the powder/granular material into the powder/granular-material discharge groove  17  on the return side can be made to be filled more easily, whereby filling efficiency of the powder/granular material, can be improved. 
     According to the metering feeder according to the present invention, metered supply of the powder/granular material can be realized with extremely high accuracy, and the metering feeder can be used widely in metered supply of various powder/granular materials. 
     REFERENCE SIGNS LIST 
     
         
           1  inner cylinder 
           2  outer cylinder 
           4  bottom plate 
           5  annular transport space 
           6  upright rotating shaft 
           7  spoke-shaped central rotating blade 
           8  outer rotating ring 
           8   a  projection 
           9  outer rotating blade 
           10  rotating disc 
           10   a  upper surface 
           11  rectangular support device 
           13  rectangular discharge opening 
           17  powder/granular-material discharge groove 
           17   c  recessed portion 
           18  vertically-movable scraper 
           19  fixed small scraper 
           23  scraper support portion 
           24  small groove 
           25  loosening rod 
           25   a  loosening portion 
           26  upward groove 
           31  block portion 
           33  air cylinder 
           33   a  vertical elevating driving shaft 
           35  housing 
         t gap 
         P 1  raised position 
         P 2  lowered position 
         S return space