Patent Publication Number: US-7913851-B2

Title: Separator for grinding mill

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part application of U.S. patent application Ser. No. 11/292,967 filed on Dec. 1, 2005 now abandoned entitled “A Separator” which is a divisional application of U.S. patent application Ser. No. 10/828,852 filed on Apr. 19, 2004, now U.S. Pat. No. 7,118,055 B2 entitled “Grinding mill”. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a separator for use in a grinding mill, particularly to a separator for use in a vertically oriented grinding mill. 
     DESCRIPTION OF RELATED ART 
     With increasing quality of life, demands on industrial products have become stricter. In particular, food and medical products have become subjected to environmental standards. The GMP standard regulates grinding mills as to ingredients, noise, iron contents (resulting from wear), temperature, and pollution. So far, few grinding mills of those produced in all countries fulfill the GMP standard. 
     Conventionally, grinding mills are designed according to the following considerations: (1) torque, (2) centrifugal force, (3) grinding force, (4) heat, and (5) noise. Separators for grinding mills are designed for effectiveness of separating various particle sizes. These criteria are interconnected. However, conventional separators insufficiently separate desired line from yet too coarse particles. 
     In U.S. Pat. No. 5,238,196 “Upright lever pressure type mill”, the present inventor has disclosed a grinding mill with a separator. As shown in  FIGS. 11 and 12 , a separator  80  has a shaft sleeve  81 , into which a shaft  90  is inserted; two ring-shaped rotating plates  82 , having a plurality of blades  83  that are radially oriented and placed on outer sides of the rotating plates  82 ; a casing  84 , shaped like a cylinder, surrounding the plurality of blades  83 ; and a circular base plate  85 , carrying the shaft sleeve  81 . 
     During grinding, ground material is carried by an air flow, passing through the separator  80 . Upon rotation of the shaft  90 , due to a centrifugal force, relatively fine particles pass through a center of the separator  80 , whereas relatively coarse particles are drawn to a periphery thereof. Since the blades  83  are taken along during the rotation of the shaft  90 , the blades  83  prevent relatively coarse particles from passing through the separator  80 , so that relatively coarse particles fall down and are ground again. 
     However, the separator shown in  FIG. 11  still has the following shortcomings: The rotating plates  82  have concentric openings, allowing air carrying ground particles to pass through. However, radial fixing plates  86 , used to connect the rotating plates  82  to the shaft sleeve  81  hinder free air flow and consequently a rising movement of ground particles, so that separation of relatively coarse from relatively fine particles is not performed effectively. 
     Furthermore, the blades  83  are mounted at a fixed vertical distance from the base plate  90 , which has an influence on which ground particles are separated to be ground again. Since the vertical distance between the blades  83  and the base plate  85  cannot be regulated during operation, fineness of grinding cannot be controlled during operation. 
     Moreover, as shown in  FIG. 12 , the blades  83  are fixed on outer sides of the rotating plates  82 , hence forces upon impact of larger clumps of grinding material are large, threatening to damage the blades  83 . 
     Finally, due to the casing  84  surrounding the blades  83 , particles hit by the blades are prevented from leaving the separator  80 , interfering with the rising air flow rather than directly falling back to be ground again, so that total grinding time becomes longer. 
     Further separators have been disclosed in U.S. Pat. No. 6,318,559 and U.S. Pat. No. 3,372,805, which work as separate units for processing already ground particles, e.g., for separating and sieving, but are not suitable for operation in conjunction with mills. 
     Therefore, conventional separators for grinding mills are still in need of improvement. 
     SUMMARY OF THE INVENTION 
     The present invention is a separator used in conjunction with a grinding mill which has a suction assembly, a grinding device, regulating devices and a driving device. The separator is mounted in a main body of the grinding mill on a rotating vertical separator shaft, comprising two support rings of equal sizes and shapes, mounted on the separator shaft with parallel orientations, having radial bridges with openings in between, which are surrounded by a plurality of mounting holes; and a plurality of blades, hingedly mounted on the mounting holes by vertical rods, for separating ground particles according to size. 
     The present invention can be more fully understood by reference to the following description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial sectional view of an embodiment of the grinding mill of the present invention. 
         FIG. 2  is a partial sectional view of an embodiment of the grinding mill of the present invention with the guiding assembly assembled. 
         FIG. 3  is a partial sectional view of the grinding mill of the present invention with the guiding assembly assembled in another embodiment. 
         FIG. 4  is a lop view of the separator and the guiding assembly of the present invention. 
         FIG. 4A  is a sectional view of the separator and the guiding assembly of the present invention. 
         FIG. 4B  is a sectional view of the separator and the guiding assembly of the present invention, indicating adjusting of the gap between the circular pan of the guiding assembly and the separator. 
         FIG. 5  is a perspective views of the drum body of the guiding assembly in the first embodiment. 
         FIG. 5A  is a perspective views of the drum body of the guiding assembly in the first embodiment, having an extension ring. 
         FIG. 5B  is a perspective views of the drum body of the guiding assembly in the second embodiment. 
         FIG. 5C  is a perspective views of the drum body of the guiding assembly in the third embodiment. 
         FIG. 6  is a perspective view of the separator and the grinding device of the present invention, 
         FIG. 7  is a perspective view of an excentric disc of the present embodiment. 
         FIG. 8  is a perspective view of the excentric disc with the grinding wheels mounted. 
         FIG. 9  is a perspective view of a grinding device of the present invention. 
         FIG. 10  is a schematic illustration of the air flow in the present invention. 
         FIG. 11  (prior art) is a side view of the separator of U.S. Pat. No. 5,238,196. 
         FIG. 12  (prior art) is a top view of the separator of U.S. Pat. No. 5,238,196, 
     
    
    
     DETAILED DESCRIPTION OK THE PREFERRED EMBODIMENTS 
     As shown in  FIGS. 1-3  and  4 A, the grinding mill of the present invention mainly comprises: a main body  10 , accommodating structural parts for grinding; a suction assembly  20 , connected with a collecting apparatus  71  for collecting ground products; a separator  30 , separating ground products according to sizes thereof; a grinding device  40 ; several regulating devices  50 ; and a driving device  60 . 
     The suction assembly  20  is placed on an upper end of the main body  10 . The separator  30 , the grinding device  40  and the regulating devices  50  are housed inside the main body  10 . A feeding hole  11  connected to a feeding apparatus  70  is cut into the main body  10 , providing raw material to be ground. The main body  10  further has a lower end with a resupplying chamber  12 . The resupplying chamber  12  has a resupplying hole  121  which via a resupplying tube  72  lakes in excess air from the collecting apparatus  71 , which is subsequently led back into the main body  10 . A draining chamber  13  is placed at the lower end of the main body  10 . A draining tube  131  leads from the draining chamber  13  to a waste chamber  14  where non-grindable components and waste from die grinding process are collected. 
     The suction assembly  20  has an upper end with a motor sleeve, a lower end which is connected with the upper end of die main body  10  and an inner space which accommodates a high-speed separator motor  22  and a separator shaft  21  that vertically reaches downwards. A frequency controller controls a centrifugal force of a separator movement around the separator shaft  21  that is needed for appropriate separation. The separator  30  has a guiding assembly  340 , which allows precisely to regulate a degree of coarseness of separated particles. A suction tube  23  leads laterally away from the suction assembly  20  into a fan apparatus  73 , that particles separated by the separator  30  are sucked out of the main body  10 . 
     Referring to  FIGS. 1-4A , the separator  30  is mounted on a top end of the separator shaft  21  inside the main body  10 , having two support rings  31  at upper and lower vertical positions and in parallel orientations. Each of the support rings  31  has a peripheral ring and an inner ring  313  of a relatively small diameter, connected to the peripheral ring by several radial bridges  311 , between which curved openings  314  are left, as shown in  FIG. 4 . A plurality of mounting boles  312  are bored into the peripheral ring. A plurality of vertical blades  32  extends outward from the peripheral rings of the two support rings  31 , fastened in the mounting holes  312  by vertical rods  321 . 
     As shown in  FIGS. 4 and 4A , for each of the support rings  31 , the inner ring  313  is connected with a shaft sleeve  315 , which in turn is fixed on the shaft  21 . The curved openings  314  of the support rings  31  are aligned, so that canals for air flow, generated by the suction device  20 , are formed. Relatively small particles pass through the curved openings  314 , whereas relatively large particles are deflected by the blades  32  and fall back into the grinding device  40  to be ground again. 
     The main characteristic of the present invention is that the support rings  31  have parallel orientations and, for each of the support rings  31 , the peripheral ring and the inner ring  313  are connected by the bridges  311 , so that air flow generated by the suction assembly  20  proceeds unhindered, without interference by blades. Hence effectiveness of separating particles is greatly increased. 
     Furthermore, the blades  32 , being mounted in the mounting holes  312  and held by vertical rods  321  as hinges, during operation in a normal state point radially outward due to a centrifugal force during rotation of the shaft  21 . When, however, hit by large particles or clumps of grinding material each of the blades  32  turns aside, deflecting impacts and avoiding being damaged. 
     Referring now to  FIGS. 2-5  , the guiding assembly  340  is placed on a periphery of the separator  30  inside the main body  10  on an upper part thereof. The guiding assembly  340  comprises a drum body  35  and a circular pan  34  with an outer diameter which is slightly smaller than the inner diameter of the drum body  35 , with a gap CI remaining in between. The circular pan  34  is mounted on the shaft  21  by a pan vertical position adjusting device, which may be a fixing screw as shown in  FIG.4A . As shown in  FIG. 4B , for fine grinding, the vertical position of the circular pan  34  is adjusted relatively high, resulting in a small gap to the drum body  35  (indicated by C 2 ). By adjusting the vertical position of the circular pan  34 , air flow and excentric components thereof are controlled. For smaller particles passing through the separator  30 , the gap C 2  is adjusted to be smaller. Hence fineness of grinding is controllable. 
     Modifying a vertical position of the blades  32  on the support rings  31  allows to control fineness of grinding, too. As shown in  FIG. 4A , the shaft sleeve  315  is fixed on the shaft  21  by a blade vertical position adjusting device which may also be a fixing screw  316  at a desired vertical position according to a desired vertical position of the blades  32 . For coarser grinding, the blades  32  are lowered, so that grinding material bypasses the blades  32  more easily. For finer grinding, the blades  32  are raised, so that larger particles of grinding material are more likely to be hit by the blades  32 . 
     The drum body  35  of the guiding assembly  340  has a periphery with a plurality of openings  351 , each of which is partly covered by an inclined lid  352 . Relatively large particles, which are accelerated outward by the centrifugal force during rotation of the shaft  21 , bypass the inclined lids  352 , hit an inner surface of the main body  10  and fall down to be grinded anew, whereas relatively small particles are kept within the drum body  35 , rising along the air flow. The arrangement with the inclined lids  352  is adapted to the air flow and allows separation of even tiny particles according to size. Thus more effective separating of ground particles according to sizes thereof is achieved. 
     Referring again to  FIGS. 3 and 5   a , in an embodiment of the present invention, a drum body  35   a  is used having an upper edge with a vertically adjustable extension ring  34   a  , providing additional space for separating larger particles through the blades  32 . 
     Referring to  FIGS. 3 and 5   b , in another embodiment of the present invention, a drum body  35   b  is used having lids  353  that are inclined inwards. As shown in  FIG. 5   c , in a further embodiment of the present invention, a drum body  35   c  is used having lids  354 ,  355  that are alternatingly inclined inwards and outwards for adjusting to the air flow carrying particles. 
     Referring now to FIGS.  1  and  6 - 10 , the grinding device  40  is placed inside the main body  10 , surrounded by a grinding ring  15 . The grinding device  40  has a main axis  41  which is driven by the driving device  60  to perform a rotational grinding movement. An eccentric disc  42  is set on the main axis  41 , carrying a plurality of grinding wheels  43  arranged to have suitable distances to the grinding ring  15 . Ramps  421 , each placed next to one of the grinding wheels  43  on the excentric disc  42 , guide raw material into two vertical sections between the grinding wheels  43  and the grinding ring  15 , preventing accumulation thereof. Furthermore, air inlets  422  are placed on the excentric disc  42 , covered by hinged lids  423 . The lids  423  freely open in the airflow that is driven by the fan apparatus  73 . 
     The driving device  60  has a main motor  61  which drives the grinding device  40 . The main motor  61  extends into a casing  62 , driving the grinding movement of the main axis  41 . A gearbox is accommodated by the casing  62 , allowing for high, middle and low speeds of the grinding movement according to raw material for optimum throughput. 
     For operating the grinding mill of the present invention, first the separator motor  22 , then the main motor  61  are turned on. Consequently, the main axis  41  and the excentric disc  42  perform the grinding movement, causing the grinding wheels  43  to revolve inside of the grinding ring  15 , performing the grinding process. 
     After switching on the fan apparatus  73 , air enters the main body  10  through the resupplying tube  72  and the resupplying hole  121  and is sucked upwards through the air inlets  422 . At the same time, raw material enters the main body  10  through the feeding hole  11 . Entering raw material is not carried away by air flow due to large particle sizes and rather falls directly on the excentric disc  42  within the grinding ring  15 . The rotating grinding movement of the excentric disc  42  causes raw material to be led along the ramps  421  on two vertical sections between the grinding wheels  43  and the grinding ring  15  and to be ground. Ground material rises with the air flow, entering the separator  30 , and is separated there, with smaller particles being carried away to the suction tube  23  and larger particles falling back into the main body  10 . Outflowing air is recycled into the main body  10  through the resupplying hole  121  and the air inlet  422 , preventing raw material from accumulating. 
     While the invention has been described with reference to preferred embodiments thereof, it is to be understood dial modifications or variations may be easily made without departing from the spirit of this invention which is defined by the appended claims.