Abstract:
A grain dropping passage constituted below a husking unit (D) serves as a winnowing room (A). A winnowed grain conveyor ( 1 ) is provided as the sole conveyor below the winnowing room (A). A winnowing wind blown by a winnowing fan (F) through a blowing room (B) passes through below the winnowed grain conveyor ( 1 ) and then rises in the winnowing room (A). The grains mixed with hulls and others are winnowed in the winnowing room (A) so as to be sorted into two kinds: winnowed grains to be received by the winnowed conveyor ( 1 ), and the other including hulls to be received by a hull conveyor ( 2 ) arranged oppositely to the winnowed grain conveyor ( 1 ) with respect to the winnowing fan (F). In this manner, powerful separation can be executed by means of winnowing wind having a large amount and large speed so as to improve a winnowing ability remarkably.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a closed air force type grain sorting mechanism (a closed winnowing system) which separates grains from hulls and others after husking so as to sort winnowed grains from hulls and others.  
         BACKGROUND OF THE INVENTION  
         [0002]    A closed winnowing system located below a husking device is conventionally well-known, as disclosed in Japanese Patent Publications No. 21188 (1963) and No. 50187 (1977), for example.  
           [0003]    [0003]FIG. 21 shows such prior art apparatus in detail. In accordance with the prior art, a closed winnowing system is located below a husking unit D including a grain hopper  23  and husking rolls  20  and  21 . In the winnowing system, two outlets are provided below the winnowing room A′. One is a first outlet  24  where winnowed grains (including husked grains and unhusked grains) fall, and the other is a second outlet  25  where lightweight particles such as fruitlessness and crashed grains being blown up fall.  
           [0004]    Further, a third outlet  26  where extremely lightweight hulls being blown away fall is provided at a reverse position of the blowing room B with respect to the winnowing fan F.  
           [0005]    After winnowing, the winnowed grains, lightweight particles and hulls are sorted into three outlets: “the first outlet  24  where winnowed grains fall”; “the second outlet  25  where lightweight particles (fruitlessness, crashed grains and the like) being blown up fall”; and “the third outlet  26  where hulls being blown away fall”.  
           [0006]    However, such sorting method has been available at a time when lightweight crashed grains and the like fallen from the second outlet  25  were taken seriously as feeding stuff for livestock and poultry. In recent years, the necessity of “the second outlet  25  where lightweight particles being blown up fall” has been decreased.  
           [0007]    Further, in this manner, a flow of winnowing wind must be guided so as to sort winnowed grains and lightweight particles between the first outlet  24  and the second outlet  25 . As a result, the winnowing wind can not set to be strong. Accordingly, a separation capacity is decreased, so that a husking process capacity of the husking unit D is also decreased whereby a malfunction in which a husking and winnowing process of large capacity can not be executed at a short time has been occurred.  
           [0008]    In a view of mentioned above, an object of the present invention is to provide a closed grain winnowing system constituted so as to sort winnowed grains and others into only two outlets of “a winnowed grain conveyor” and “a hull conveyor” after the winnowing.  
         SUMMARY OF THE INVENTION  
         [0009]    According to the present invention, a closed air force type grain sorting mechanism (a closed winnowing system) having a grain dropping passage serving as a winnowing room below a husking unit, wherein a winnowing fan blows a winnowing wind through a blowing room into the lower end of the winnowing room. A winnowed grain conveyor is provided as the sole conveyor (outlet) positioned below the winnowing room. A hull conveyor is provided at a reverse position of the winnowing room with respect to the winnowing fan. A mixture of grains, hulls and others falling from the husking unit are separated into two groups: one for winnowed grains to be received by the winnowed grain conveyor, and the other for hulls and lightweight particles to be received by the hull conveyor. In this manner, powerful separation can be executed by means of winnowing wind having a large amount and large speed as compared with a conventional case in which the winnowed grains and others are sorted into the three outlets.  
           [0010]    The present invention is also constituted so as to provide the winnowing room and the blowing room adjacently to each other through a shield plate. The winnowing fan is provided within the blowing room so as to blow the winnowing wind to a downward portion of the winnowing room through the blowing room. The shield plate provided between the winnowing room and the blowing room is vertically constituted. The winnowing room is provided along the shield plate so as to be vertically linear. The winnowed grain conveyor is provided in the lower end of the vertically linear winnowing room so as to allow the winnowing wind to pass through below the winnowed grain conveyor and to blow up for the winnowing room. In this manner, the grains and others falling in the grain dropping passage can be separated by the winnowing wind vertically blown up, thereby improving a winnowing accuracy to improve a winnowing ability.  
           [0011]    Further, in accordance with the present invention, a winnowing wind shutter adjusting a speed and amount of the winnowing wind supplied in the winnowing room is provided in a passage which returns part of the air discharged from the winnowing fan to a hull blowing wind passage. In this manner, (unlike a ratio of the winnowing wind flowing into the winnowing room is conventionally changed by a first outlet wind amount adjusting shutter and a second outlet wind amount adjusting shutter) since the wind amount flowing from the blowing room to the winnowing room is uniquely adjusted, the wind amount adjustment can be executed accurately. Accordingly, there is no need to station a skilled operator because the adjustment of the winnowing wind can be executed easily by any worker, whereby the winnowing accuracy can be improved.  
           [0012]    Further, in the winnowing room is provided at least one sectionally triangularly shaped plate serving as a grain guide plate as well as a winnowing wind guide plate. Faces (normally, two faces) of the triangular plate with which dropping grains collide are used to guide the grains. Such triangular plate also serves as a reinforcing plate increasing the strength of the winnowing apparatus.  
           [0013]    In addition, the winnowing fan is constituted by right and left fans, and a winnowing wind direction adjusting plate onto which the winnowing wind from the winnowing fan is applied is provided in a lower portion of the blowing room. In this manner, the winnowing wind generated by the right and left fins is fully diffused in a closed housing so as to be capable of setting as an uniform winnowing wind. In this manner, the winnowing accuracy and the winnowing ability can be also improved.  
           [0014]    Further, a winnowing wind shutter plate for adjusting the winnowing wind amount is provided in a blow-off side of the winnowing fan so as to release the winnowing wind from the winnowing wind fan to the hull conveyor side. In this manner, the power of the winnowing wind adjusted by adjusting the amount of wind released from the blowing room to the hull blowing wind passage instead of adjusting the direction of the wind within the blowing room according to the conventional manner. Accordingly, the power of the winnowing wind can be set suitably and easily, thereby improving the winnowing ability. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIGS. 1, 2 and  3  are, respectively, a front view, a left side view and a right side view of the whole of a closed winnowing system according to the present invention, which is equipped with a husking unit D.  
         [0016]    [0016]FIG. 4 is an enlarged front view of the closed winnowing system while FIG. 5 is a sectional right side view of the same. Furthermore, FIG. 6 is a sectional view showing a winnowing wind passage of the closed winnowing system.  
         [0017]    [0017]FIGS. 7, 8,  9 ,  10 ,  11  and  12  are, respectively, a plan view, a front view, a bottom view, a right side view, a left side view and a rear view showing only the closed winnowing system.  
         [0018]    [0018]FIG. 13 is a sectional side view of a part of the closed winnowing system in which winnowing fans F, a blowing room B, winnowing wind shutters  6  and back-flow shield plates  45  are provided. FIG. 14 is a perspective view of the same.  
         [0019]    [0019]FIG. 15 is a perspective view of a part of the same of FIG. 14 showing a state of opening the separating shutter  6 , and  
         [0020]    [0020]FIG. 16 is a perspective view of the same showing a state of closing the winnowing wind shutters  6 .  
         [0021]    [0021]FIG. 17 indicates measurement points of a wind amount and a wind speed provided in the closed winnowing system, and  
         [0022]    [0022]FIG. 18 shows the wind speed in the measuring points of FIG. 17.  
         [0023]    [0023]FIG. 19 is a block diagram of a grain husking-and-separating plant into which the closed winnowing system according to the present invention is incorporated.  
         [0024]    [0024]FIG. 20 is a block diagram of a grain husking-and-winnowing plant into which a conventional closed winnowing system is incorporated, and FIG. 21 is a sectional front view of the conventional closed winnowing system. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    With reference to the attached drawings, the present invention will be described in detail.  
         [0026]    At first, referring to FIGS. 19 and 20, functions required of a closed winnowing system according to the present invention in a grain husking-and-winnowing plant are described in contrast to a conventional closed winnowing system.  
         [0027]    [0027]FIG. 20 shows a flow of processes executed with the conventional grain husking-and-winnowing plant. Firstly, dried raw grains are thrown into a lower hopper located at a foot of a raw grain feeding elevator  19 , and then this elevator is operated to put these dried raw grains into a roughing-out flow adjustment tank  28 . If some of the grains brim over after filling the roughing-out flow adjustment tank  28 , then a switching shutter  50  is operated to switch the flow of the grains so that the over-flown grains are directed to return to the lower hopper of the raw wind amount is provided in a blow-off side of the winnowing fan so as to release the winnowing wind from the winnowing wind fan to the hull conveyor side. In this manner, the power of the winnowing wind adjusted by adjusting the amount of wind released from the blowing room to the hull blowing wind passage instead of adjusting the direction of the wind within the blowing room according to the conventional manner. Accordingly, the power of the winnowing wind can be set suitably and easily, thereby improving the winnowing ability.  
       BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    [0028]FIGS. 1, 2 and  3  are, respectively, a front view, a left side view and a right side view of the whole of a closed winnowing system according to the present invention, which is equipped with a husking unit D.  
         [0029]    [0029]FIG. 4 is an enlarged front view of the closed winnowing system while FIG. 5 is a sectional right side view of the same. Furthermore, FIG. 6 is a sectional view showing a winnowing wind passage of the closed winnowing system.  
         [0030]    [0030]FIGS. 7, 8,  9 ,  10 ,  11  and  12  are, respectively, a plan view, a front view, a bottom view, a right side view, a left side view and a rear view showing only the closed winnowing system.  
         [0031]    [0031]FIG. 13 is a sectional side view of a part of the closed winnowing system in which winnowing fans F, a blowing room B, winnowing wind shutters  6  and back-flow shield plates  54  are provided. FIG. 14 is a perspective view of the same.  
         [0032]    [0032]FIG. 15 is a perspective view of a part of the same of FIG. 14 showing a state of opening the separating shutter  6 , and FIG. 16 is a perspective view of the same showing a state of closing the winnowing wind shutters  6 .  
         [0033]    [0033]FIG. 17 indicates measurement points of a wind amount and a wind speed provided in the closed winnowing system, and FIG. 18 shows the wind speed in the measuring points of FIG. 17.  
         [0034]    [0034]FIG. 19 is a block diagram of a grain husking-and-separating plant into which the closed winnowing system according to the present invention is incorporated.  
         [0035]    [0035]FIG. 20 is a block diagram of a grain husking-and-winnowing plant into which a conventional closed winnowing system is incorporated, and FIG. 21 is a sectional front view of the conventional closed winnowing system.  
         [0036]    [0036]FIG. 22 is a table of wind amounts at various portions in the closed casing of the closed winnowing system according to the present invention.  
       DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]    With reference to the attached drawings, the present invention will be described in detail.  
         [0038]    At first, referring to FIGS. 19 and 20, functions required of a closed winnowing system according to the present invention in a grain husking-and-winnowing plant are described in contrast to a conventional closed winnowing system.  
         [0039]    [0039]FIG. 20 shows a flow of processes executed with the conventional grain husking-and-winnowing plant. Firstly, dried raw grains are thrown into a lower hopper located at a foot of a raw grain feeding elevator  19 , and then this elevator is operated to put these dried raw grains into a roughing-out closed winnowing system K′ has three outlets: “the first outlet  24  where winnowed grains fall”; “the second outlet  25  where lightweight particles being blown up fall”; and “the third outlet  26  where hulls being blown away fall”.  
         [0040]    In the conventional closed winnowing system K′, the winnowing room A′ includes a winnowing passage with a first wind amount adjustment shutter  51  for the first outlet  24  and a second wind amount adjustment shutter  52  for the second outlet  25 . In other words, in the conventional winnower, the air flow to lead the fall of the winnowed grains into the first outlet  24  must be adjusted by the first wind amount adjustment shutter  51 , while the wind amount to lead the fall of the lightweight crashed or fruitless grains into the second outlet  25  must be adjusted by the second wind amount adjustment shutter  52 . Such wind amount adjustment shutters are not provided in the vicinity of the winnowing fan F or of the blowing room B.  
         [0041]    The conventional closed winnowing system K′ is so designed that the opening of these shutters  51  and  52  must be adjusted by an operator. To operate the separator and to attain a best result, it has been necessary to station a specially trained skilled operator, who makes fine and difficult adjustment on the opening of the first wind amount adjustment shutter  51  and the opening of the second wind amount adjustment shutter  52 .  
         [0042]    In contrast to the conventional winnowing system, the closed winnowing system K according to the present invention has only “a winnowed grain conveyor  1  where winnowed grains fall” below the wind-powered separation room A, as shown in FIG. 6. There is no conveyor that represents the second outlet of the conventional winnower. In other words, in this part of the winnower, no separation is executed to differentiate the “winnowed grains” from the “lightweight fruitlessness and crashed grains”.  
         [0043]    Accordingly, there is no need to provide the first wind amount adjustment shutter  51  and the second wind amount adjustment shutter  52  of the conventional winnower in the winnowing room A of the winnower according to the present invention.  
         [0044]    Instead, the winnowing system K according to the present invention has winnowing wind shutters  6  to adjust the degree of separation between “the winnowed grain conveyor  1  where winnowed grains fall” and “the hull conveyor  2  where hulls are blown away and fall”. These shutters  6  are provided near the winnowing fan F, which is located at the upper part of the blowing room B. With this construction, unwanted part of the winnowing wind is bypassed and discharged from the blowing room B to a hull blowing wind passage G by the adjustment of the shutters  6 .  
         [0045]    Now, with reference to FIGS.  1  to  3 , a description is given of the whole construction of the closed winnowing system K according to the present invention.  
         [0046]    As shown in FIG. 1 and the like, the closed winnowing system K mainly comprises a closed housing R which is located at the bottom, a husking unit D which is set on the closed housing R, and a hopper  23  which is mounted on the husking unit D. In addition, a hull shutter  11  is provided at a location where the hull conveyor  2  extrudes from the closed housing R. The closed housing R includes a winnowing room A, a blowing room B and winnowing fans F; which are important components of the present invention.  
         [0047]    On the closed housing R and near the husking unit D, a husking drive motor M 1  is provided to power the husking unit D.  
         [0048]    [0048]FIGS. 4 and 5 show specifically the construction of the closed housing R. As shown in these drawings, in addition to the husking drive motor M 1 , a winnowing drive motor M 2 , which powers the winnowing fans F, the winnowed grain conveyor  1  and the hull conveyor  2 , is provided in the closed housing R.  
         [0049]    [0049]FIG. 5 is a sectional view taken along a plane that passes through the winnowing fans F. It is clear from this view that the winnowing fans F comprise left and right fans F 1  and F 2 .  
         [0050]    FIGS.  7  to  12  are six surfaces views of the closed housing R drawn in an identical scale, which are taken along the directions of the six surfaces of the closed housing R. The positional relation of “the winnowed grain conveyor  1  where winnowed grains fall” and “the hull conveyor  2  where hulls are blown away and fall” and the heights of these conveyors are clearly understandable from these views. As shown in FIG. 7 and in FIGS.  10  to  12 , a belt cover  55  is attached on the rear side of the closed housing R to cover a V belt  22 . The V belt  22  transmits power from the winnowing drive motor M 2  to the winnowed grain conveyor  1 , the hull conveyor  2  and the winnowing fans F.  
         [0051]    FIGS.  13  to  16  show, in detail, the construction of the winnowing fans F, which are provided in the closed housing R.  
         [0052]    The winnowing fans F are embodied in two pieces, i.e., the left fan F 1  and the right fan F 2 , because the closed housing R is relatively wide. The winnowing fans F are impellers having vanes  37 . Each of fans F 1  and F 2  is provided with a vane supporter  46  to which six vanes  37  are fitted so as to generate a sizable wind amount.  
         [0053]    The winnowing fans F of the closed winnowing system according to the present invention have the following features. Three winnowing wind intake ports  56  are provided, one between left and right fan housings  4 , which accommodate the left and right fans F 1  and F 2  respectively, and the other two on the left and right outer sides of the respective fan housings  4 . Furthermore, three back flow blocking plates  54  are provided below the winnowing wind intake ports  56  to prevent the winnowing wind from returning to the hull blowing wind passage G through this section.  
         [0054]    Moreover, three winnowing wind shutters  6  are provided above the respective winnowing wind intake ports  56  and beside the left and right fans F 1  and F 2 . The winnowing wind shutters  6  are connected with one another and are rotatably adjusted as a one-piece body.  
         [0055]    In addition, winnowing wind back flow preventing plates  35  are provided to shut the openings that exist above the fan housings  4  and thereby preventing a back flow of air from the blowing room B to the hull blowing wind passage G through this section.  
         [0056]    In this construction, the winnowing wind is generated and sent downward from the left and right fans F 1  and F 2 . With the winnowing wind blowing, the rotation, i.e., the movement upward or downward, of the winnowing wind shutters  6  determines the flow of the air returning from the blowing room B to the hull blowing wind passage G, which, in turn, adjusts the wind amount into the winnowing room A.  
         [0057]    In other words, the present invention has made it possible to adjust the winnowing wind flowing from the winnowing fans F to the winnowing room A only with the winnowing wind shutters  6 . This way of adjustment is different from that of the prior art, which adjusts the winnowing wind that is supplied once into the direction of the winnowing room A′, separately with the first wind amount adjustment shutter  51  and with the second wind amount adjustment shutter  52  as shown in FIG. 21.  
         [0058]    In the closed winnowing system according to the present invention, the above mentioned three winnowing wind intake ports  56 , which are provided near the left and right fans F 1  and F 2 , are open in the direction of the hull blowing wind passage G as shown in FIGS.  13  to  16 .  
         [0059]    Therefore, the air in the hull blowing wind passage G is taken in through the winnowing wind intake ports  56  from the sides of the left and right fans F 1  and F 2  and discharged as the winnowing wind through discharge openings  58 , which are located under the fans F 1  and F 2 .  
         [0060]    As shown in FIG. 6 and FIG. 13, a winnowing wind direction adjusting plate  5  is provided below the left and right fans F 1  and F 2  and above a bottom plate, slantingly with the upper edge thereof toward the winnowing room A. In this way, the winnowing wind discharged from the fans F 1  and F 2  hits the winnowing wind direction adjusting plate  5  so as to become evenly distributed widthwise.  
         [0061]    Now, the winnowing room A and the blowing room B are described generally in reference to FIG. 6.  
         [0062]    Although FIG. 6 does not show the husking unit D, which is mounted on the closed housing R and includes the left and right husking rolls  20  and  21  shown in FIG. 21, grains are husked by the husking rolls  20  and  21 , and resultant grains and hulls fall downward. Entering the closed housing R, the grains and hulls hit, at first, a collision plate  30  shown in FIG. 6, and then, fall along a zigzag course that is defined by five grain-flow plates, three of them  38 ,  40  and  42  positioned on the left and the other two  39  and  41  on the right in FIG. 6.  
         [0063]    The winnowing room A is located under the grain-flow plate  42 , which is positioned on the left hand. In the winnowing room A, a horizontally arranged air-course blocking plate  34 , a left-side triangular grain-flow wind-blocking plate  10 , an outward grain-flow plate  31  and a final grain-flow plate  32  are provided on the left side in this downward order. The left-side triangular grain-flow wind-blocking plate  10  is arranged in a right-angled-triangular form to lead the winnowed grains to the winnowed grain conveyor  1 . The final grain-flow plate  32  is arranged so as to lead the winnowed grains to the winnowed grain conveyor  1  finally. The outward grain-flow plate  31  is positioned above the final grain-flow plate  32  and arranged to direct the winnowed grains outwardly.  
         [0064]    Also, in the winnowing room A, a right-side upper triangular grain-flow wind-blocking plate  8 , a right-side lower triangular grain-flow wind-blocking plate  7  and an inward grain-flow plate  43  are provided on the right side in this downward order. The right-side upper and lower triangular grain-flow wind-blocking plates  7  and  8  are arranged in triangular forms to lead the winnowed grains to the winnowed grain conveyor  1 . The inward grain-flow plate  43  is arranged substantially parallel with the outward grain-flow plate  31  so as to lead the winnowed grains to the winnowed grain conveyor  1 . The upper edge of the inward grain-flow plate  43  is fixed on a vertical shield plate  3 .  
         [0065]    In this arrangement, the winnowing wind, after being generated by the winnowing fans F hits the winnowing wind direction adjusting plate  5  in the blowing room B and then flows through the opening between the bottom of a conveyor gutter  1   a  which constitutes the winnowed grain conveyor  1  and the bottom plate of the closed housing R. Then, the winnowing wind flows through the passage located below the final grain-flow plate  32  into the winnowing room A.  
         [0066]    A wind direction adjusting plate  33  is provided above the final grain-flow plate  32  in the winnowing room A. By this wind direction adjusting plate  33  and the above mentioned horizontal air course blocking plate  34 , the winnowing wind is divided into two directions, one toward the outward grain-flow plate  31  and the other toward the left-side triangular grain-flow wind-blocking plate  10 .  
         [0067]    Then, part of the winnowing wind passes through an opening  44  between the horizontal air course blocking plate  34  and an inner side-wall of the closed housing R, and part of the winnowing wind also passes through the opening between the left-side triangular grain-flow wind blocking plate  10  and the grain-flow plate  42 .  
         [0068]    On the left side of the falling grain passage in the closed housing R, the winnowing wind flows through two winnowing wind passages. One flow passes between the grain-flow plate  42  and the left-side triangular grain-flow wind blocking plate  10  and the other flow passes between the left-side triangular grain-flow wind blocking plate  10  and the outward grain-flow plate  31 .  
         [0069]    On the right side of the falling grain passage in the closed housing R, the winnowing wind that has passed through the two winnowing wind passages located on the left-side now flows through three winnowing wind passages. One flow passes between the grain-flow plate  42  and the right-side upper triangular grain-flow wind blocking plate  8 , another flow passes between the right-side upper triangular grain-flow wind-blocking plate  8  and the right-side lower triangular grain-flow wind-blocking plate  7 , and the other flow passes between the right-side lower triangular grain-flow wind blocking plate  7  and the inward grain-flow plate  43 .  
         [0070]    The winnowing wind flowing through these passages blows upward the hulls that have fallen into the closed housing R and carries the hulls into the hull blowing wind passage G.  
         [0071]    The winnowing wind that has reached the hull blowing wind passage G is taken in again through the winnowing wind intake ports  56 , which are located on the sides of the left and right fans F 1  and F 2 , and recirculated by the fans F 1  and F 2  from the blowing room B to the winnowing room A.  
         [0072]    According to the present invention, the winnowing room A and the blowing room B of the closed winnowing system are positioned next to each other with the vertical shield plate  3  partitioning these two rooms. The above mentioned winnowed grain conveyor  1  is placed at the bottom of the winnowing room A, which is arranged vertically along the vertical shield plate  3 . In this construction, the winnowing fans F placed in the blowing room B generate and supply the winnowing wind from the blowing room B through the opening provided under the winnowed grain conveyor  1  to the bottom of the winnowing room A, where the winnowing wind now flows upward.  
         [0073]    Since the winnowing wind is directed upward, the grains are winnowed so as to be separated from the hulls in a most efficient and accurate way.  
         [0074]    [0074]FIG. 17 shows points in the winnowing room A where air flow is measured, and FIG. 18 shows measured values of the winnowing wind from front side to rear side of the closed housing R in each measuring point.  
         [0075]    As previously mentioned, since the winnowing wind direction adjusting plate  5  is provided below the winnowing fan F in the blowing room B, the flow of the winnowing wind is uniform throughout the width of the closed housing R, i.e., from the front side to the rear side, as shown in the graph of FIG. 18.  
         [0076]    In the present invention, the closed housing R includes the horizontal air course blocking plate  34 , the left-side triangular grain-flow wind blocking plate  10 , the outward grain-flow plate  31  and the final grain-flow plate  32  on the left side of the lower end of the grain-flow plate  42 , and the right-side upper triangular grain-flow wind blocking plate  8 , the right-side lower triangular grain-flow wind blocking plate  7  and the inward grain-flow plate  43  on the right side of the lower end of the grain-flow plate  42 . As a result, the winnowing wind flows through the two passages defined by these plates on the left side and then flows through the three passages defined by these plates on the right side. While the winnowing wind is dispersed through these winnowing wind passages in this way, the wind speed at each point is maintained substantially constant, with speed values at the measured points ( 7 ), ( 8 ), ( 9 ), ( 10 ), ( 14 ) and ( 15 ) being approximately 4 to 7 m/s, respectively, though the flow amount is different as described below. In this arrangement, grains after being husked are exposed to the winnowing wind at a number of steps to make accurate the separation of the grains from the hulls.  
         [0077]    [0077]FIG. 22 shows the flow amount measured at each point. The flow amount differs as listed in the table, however there isn&#39;t much difference in the wind speed as shown in FIG. 18 since the closed winnowing system according to the present invention is designed to keep the wind speed substantially constant.  
         [0078]    Further, according to the present invention, the grain-flow plate  42 , the left-side triangular grain-flow wind-blocking plate  10 , the horizontal air course blocking plate  34 , the right-side upper triangular grain-flow wind blocking plate  8 , the right-side lower triangular grain-flow wind blocking plate  7 , the inward grain-flow plate  43 , the final grain-flow plate  32 , etc., which are provided in the wind-powered separation room A, are made of abrasion resistant materials such as stainless steel to minimize the abrasion caused by particles of silicon included in grains.  
       INDUSTRIAL APPLICABILITY OF THE INVENTION  
       [0079]    As mentioned above, a structure of the present invention is usable for a closed winnowing system for selecting and sorting winnowed grains and hulls after husking, and specially suitable for improving a winnowing process capacity of grains.