Abstract:
The present document shows a separator for separating granular material, such as seed, fertilizer or pesticide, from a material-laden airflow (FI). The separator comprises a separator zone (Z) having an inlet ( 11 ) for a material-laden airflow, a material outlet ( 13 ) and an air outlet ( 12, 12 ′), and at least two separator parts ( 15, 15 ′), which extend only substantially along a material flow (FM) in the separator zone (Z) and between which is formed a separator gap ( 12, 12 ′), which is sufficiently narrow to allow air, but not the granular material, to pass through it. At the material outlet ( 13 ), the separator gap ( 12, 12 ′) is at least partially open, viewed in a direction which is substantially parallel with the material flow (FM), so that material which gets stuck in the separator gap ( 12, 12 ′) is allowed to leave this by means of displacement principally along the material flow (FM).

Description:
TECHNICAL FIELD 
       [0001]    The present document relates to a separator for separating granular material from an air stream in a so called “nursing-system” or “product-on-demand-system” in an agricultural implement, such as a seed drill, a precision seed drill, a fertilizer spreader or a pesticide spreader. The document also relates to a metering device comprising such a separator, to an agricultural implement comprising such a metering device, and to a method for, in an agricultural implement, separating granular material. 
       BACKGROUND 
       [0002]    It is known to provide seed drills in which a central seed container is arranged to feed seed to a plurality of row units, each of which comprises a measuring device for controlling the dispensed quantity of seed for the attainment of a predefined mutual spacing between seedlings belonging to the respective row. Each such row unit can comprise a respective distributed seed container, connected to a metering device, and the central seed container is arranged to feed seed to the distributed seed container. 
         [0003]    The feed from the central seed container to the distributed seed container can be realized with the aid of an air stream, which is produced with the aid of an overpressure at the central seed container. 
         [0004]    In order to separate the seed from the air stream, there is a need for a separator which has the capacity to effectively separate seed from the air stream and which has high operating reliability. It is especially desirable to provide a separator which has the capacity to effectively separate seed without being clogged by impurities, such as seed coats, dust, parts of damaged seeds, plant residues, clumps of mordant, parts of seed bags, or other material which can be present in the environment in question. 
       SUMMARY 
       [0005]    One object is thus to provide a separator and a separation method which eliminate or reduce the problems with the prior art. 
         [0006]    The invention is defined by the appended independent patent claims. Non-limiting embodiments emerge from the dependent patent claims, the appended drawings and the following description. 
         [0007]    According to a first aspect, a separator for separating granular material, such as seed, fertilizer or pesticide, from a material-laden airflow is provided. The separator comprises a separator zone having an inlet for a material-laden airflow, a material outlet and an air outlet; and at least two separator parts, which extend only substantially along a material flow in the separator zone and between which is formed a separator gap, which is sufficiently narrow to allow air, but not the granular material, to pass through it. At the material outlet, the separator gap is at least partially open, viewed in a direction which is substantially parallel with the material flow, so that material which gets stuck in the separator gap is allowed to leave this by means of displacement principally along the material flow. The risk of material clogging the separator gap is hereby reduced. 
         [0008]    A distance between the separator parts can increase along the material flow and/or along an air outlet flow. 
         [0009]    The fact that the separator comprises separator parts which extend only along the material flow and have increasing gap widths reduces the risk of material getting stuck in the gap and thereby impairing the working of the separator. 
         [0010]    The separator parts can comprise a plurality of ribs extending along the material flow. 
         [0011]    The separator can have a plurality of separator gaps, which are distributed radially around at least a part of the separator zone. 
         [0012]    The separator can comprise a base part situated at the material outlet and having a material outlet opening, the separator parts connecting to the edge of the material outlet opening at a greater radial distance from the centre of the opening than that at which the separator parts connect to the edge of an inlet opening. 
         [0013]    The risk of material clogging the gap is thus reduced further. In addition, production of the separator by casting or injection moulding is facilitated. 
         [0014]    The separator parts can span a substantially cylindrical, frustoconical, prism-shaped or frustum-shaped inner face. 
         [0015]    The separator parts can connect to the edge of the material outlet opening via a substantially radially extending spacer portion. 
         [0016]    The base part can have an axially continuous recess, which substantially coincides with the separator gap and extends radially beyond an inner face of the separator parts, and preferably past an outer face of the separator parts. 
         [0017]    The inlet can be situated at a higher vertical level than the material outlet. 
         [0018]    According to a second aspect, a metering device for metering and dispensing granular material, such as seed, fertilizer or pesticide, is provided. The metering device can comprise a singling device configured to produce a flow of individual granules from the granular material, in which flow the granules are fed at a predefined mutual spacing; and a material inlet for feed-in of the granular material to the singling device. A separator according to that which has been described above is arranged such that its inlet is connected to a feed duct for feeding a material-laden airflow and such that its material outlet is connected to the material inlet. 
         [0019]    The air outlet of the separator can be connected to a duct for pressurization of the singling device, so that airflow from the separator is connected to an air inlet of the metering device. 
         [0020]    The air inlet and the material inlet can be connected to the metering device on a high-pressure side of a singling disc. 
         [0021]    According to a third aspect, an agricultural implement for spreading granular material, such as seed, fertilizer or pesticide, is provided, comprising a central container for the granular material; at least two metering devices according to that which has been described above; and at least two feed ducts for feeding the granular material from the central container to the respective metering device. 
         [0022]    According to a fourth aspect, a method for, in an agricultural implement, separating granular material, such as seed, fertilizer or pesticide, from a material-laden air stream is provided. The method comprises introducing the material-laden air stream into a separator zone, passing the granular material through the separator zone along a separator gap which, at a material outlet, is at least partially open in a direction which is substantially parallel with a material flow, so that material which gets stuck in the separator gap is allowed to leave this by means of displacement principally along the separator gap, and feeding the granular material separated from the material-laden air stream to a metering device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a schematic sectional view of a separator according to one embodiment. 
           [0024]      FIG. 2  is a schematic sectional view along the line A-A in  FIG. 1 . 
           [0025]      FIG. 3  is a schematic sectional view of a first system in which the separator which is described herein can be used. 
           [0026]      FIGS. 4   a - 4   b  are schematic sectional views of a second system in which the separator which is described herein can be used. 
           [0027]      FIG. 5  is a schematic perspective view of an agricultural implement  100 . 
           [0028]      FIG. 6  is a schematic perspective view of a row unit  105 . 
           [0029]      FIG. 7  is a schematic perspective view of a metering device  109  with an integrated separator unit  112 . 
           [0030]      FIG. 8  is a sectional view of the metering device in  FIG. 7 . 
           [0031]      FIGS. 9   a - 9   d  are schematic views of a separator unit. 
           [0032]      FIGS. 10   a - 10   b  show further views of the separator unit in  FIGS. 9   a - 9   d.    
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0033]      FIGS. 1 and 2  show in schematic representation a separator  1 , which has an inlet  11 , a plurality of air outlets and a material outlet  13 . The inlet  11  can be surrounded by an inlet flange  14  and the material outlet  13  can be surrounded by an outlet flange  16 . The air outlets are formed by gaps  12  between separator parts  15 . 
         [0034]    The separator parts  15  can together define a geometric body, which extends between the inlet and the material outlet. The inlet  11  and the material outlet  13  can be substantially concentrically aligned with each other, so that a separator zone Z extends substantially linearly between the inlet  11  and the material outlet  13 , and so that openings to the inlet  11  and the material outlet  13  define substantially parallel planes. 
         [0035]    The separator zone can in this case be substantially cylindrical or frustoconical with, for example, circular, oval or elliptical cross section. Alternatively, the body can have a prismatic shape or the shape of a frustum, for example with square or rectangular cross section. Other cross sections having, for example, the shape of a polygon, trapezoid, etc. are conceivable. 
         [0036]    Alternatively, openings to the inlet  11  and the material outlet  13  can define non-parallel planes. In such cases, the separator zone Z can extend linearly or in a curved path between the inlet  11  and the material outlet  13 . The separator zone can thus define a body which has the form of a curved pipe with cross section according to that which has been stated above for the separator zone Z. 
         [0037]    In the example shown in  FIGS. 1-2 , the separator zone has the form of a right-angled cylinder with circular cross section. 
         [0038]    The inlet flange  14  and the material outlet flange  16  can be adapted to the space in which the separator is to be placed, for example in order to form a seal against walls which form the space. In the example shown in  FIGS. 1-2 , the material outlet flange  16  has a square shape and the material inlet flange has a circular cross section. 
         [0039]    Between the separator parts  15  are formed gaps  12 , through which air (and small particles), but not the material to be separated from the airflow, can pass. The separator gap should thus have a, at its inner face, maximum width which is less than a minimum diameter of the granular material to be separated. The separator can be configured as an exchangeable part, which is chosen from amongst a plurality of like components with, for example, different gap width, in order to suit the type of granular material which is to be fed and separated. 
         [0040]    The gap width b can be increasing outwards in the radial direction, i.e. in a direction substantially parallel with the outlet airflow FL. The gap  12  can, for example, have a width b which is larger at the outward-facing face of the separator part  15  than at the inward-facing face of the separator part  15 . This can be realized, for example, by the separator parts having a cross section, viewed, for example, in the plane A-A, perpendicular to the material flow FM, which is outwardly tapering, for example triangular, trapezoidal, semi-circular, etc. 
         [0041]    At the material outlet  13 , the separator gap  12 ,  12 ′ can be open in a direction substantially parallel with the material flow FM. The result is that material stuck in the separator gap  12 ,  12 ′ can be conducted by the material flow FM towards the material outlet  13  and, when reaching the end of the separator gap  12 ,  12 ′, comes loose and is conducted onward with the material flow FM. 
         [0042]    According to one embodiment, the material outlet  13  can be configured with an edge  13   a  facing towards the opening. The separator parts  15  can connect to the edge  13   a  via spacer portions  18 . Tangentially between the spacer portions  18 , a number of axially continuous recesses  18  can be formed in the material outlet flange  16 . The recesses  18  can coincide with the gaps  12 , so that the openings formed by the gap continue radially outwards in the material outlet flange  16 . 
         [0043]    The separator parts  18  can thus connect to the edge portion  13   a  of the material outlet  13  at a larger radius than that at which the ribs connect to the edge portion  11  a of the material inlet  11 . 
         [0044]    Alternatively, the separator gap  12  can continue axially through the material outlet flange, implying that a radial depression with a depth corresponding to the radial wall thickness of the separator parts  18  is produced in the edge  13   a . The depth of the radial depression can be, for example, 20%-100% of the radial wall thickness. 
         [0045]    The gap width b can also be increasing in the axial direction towards the material outlet  13 , i.e. in a direction substantially parallel with the material flow FM. This can be realized by the separator parts being downwardly tapering and/or by the whole of the body which is spanned by the separator parts being conical. 
         [0046]    In  FIG. 3  is shown a system  20  in which the herein shown separator can be used. The system comprises an inlet duct  21 , in which a material-laden air flow FI from, for example, a central container can be fed, and a container  22 , in which separated material can be collected, for example for onward feeding with the aid of a metering device ( FIGS. 7-8 ), which can have the form of a singling device. Between the inlet duct  21  and the container  22  is arranged the separator  1 . In this embodiment, the separator is arranged such that airflow FL flowing out from this is released to the environment. 
         [0047]    In  FIGS. 4   a - 4   b  is shown another system  20 ′, in which the herein shown separator  1  can be used. This system  20 ′ comprises, apart from the parts in  FIG. 3 , also a separator chamber  23 , which encloses the separator, and a waste air duct  24 , which is connected to the separator chamber  23  and enables the utilization of air FL flowing out from the separator, and of therewith associated air pressure. The waste air duct  24  can also prevent the air FL from the inlet duct  21  from being released to the environment, by virtue of the fact that the air is instead recycled, for example, to feed material from the metering device. 
         [0048]    As indicated by the dashed lines in  FIGS. 4   a  and  4   b , the airflow FL from the separator  1  can, for example, be led to a drive air duct which supplies the metering device with a drive airflow FD. 
         [0049]      FIG. 5  shows an agricultural implement  100  in the form of a precision drill. The agricultural implement comprises a frame  106 ,  107 , which supports a central seed container  102  from which seed is driven with the aid of a blower  101  via feed ducts  103  to a plurality of (here eight) row units  105 . The agricultural implement  100  also has a pair of supporting wheels  104 , which can be used as support for the agricultural implement  100  during sowing and which can be height-adjustable so as also to be able to constitute transport support in road transport. 
         [0050]      FIG. 6  shows a row unit  105  of the agricultural implement  100  in  FIG. 5  and, more specifically, the row unit furthest to the left in  FIG. 5 . 
         [0051]    The row unit  105  can be attached to a transverse part  107  of the frame of the agricultural implement  100 . A height-adjusting mechanism  114  supports a metering device  109 , as well as a sowing device  110 . The metering device  109  is fed via an air duct  108  with an airflow FD, which can pressurize the metering device and possibly also be used to dispense the seed from the metering device. The airflow FD can be produced with the aid of the blower  101  or with the aid of a separate blower. Via a feed duct  103 , the metering device  109  is fed with an airflow FI mixed with seed. 
         [0052]    A separator unit  112  is arranged to separate from the airflow FI the seed entering the feed duct  103 . 
         [0053]    From the separator unit  112 , outgoing air is returned to the drive air duct  108  and fed together with the drive airflow FD via a drive air inlet  111  to the metering device  109 . 
         [0054]      FIG. 7  shows a perspective view of the metering device  109  and of ducts which run into this same, inclusive of the drive air inlet  111 , the feed duct  103  and the drive air duct  108 . In  FIG. 7  can also be seen a casing  113  for the motor (for example an electric motor) which drives a singling device  116  in the metering device  109 . The seed outlet  115 , via which seed is fed from the metering device  109  to the sowing device  110 , can also be seen. 
         [0055]    In  FIG. 8  is shown a sectional view of the metering device  109 . The separator unit  112  is here shown in sectioned view. The metering device  109  has a material inlet  117  and it can be seen how the material outlet space  1122  in the lower portion of the separator unit  112  is open towards a space in the metering device  109  in which a singling disc  116  is rotatable and in which a positive air pressure from the drive air inlet  111  is present. The material outlet space  1122  of the separator unit  109  is open towards the space containing positive air pressure, so that the seed is fed to the singling disc  116  with the aid of gravitational force. 
         [0056]    In  FIGS. 9   a - 9   d  and  10   a - 10   b  is shown an embodiment of the separator unit  112 . The separator unit  112  comprises a casing enclosing an inlet space  1121 , a material outlet space  1122  and an air outlet space  1123 . A separator  1 ′ is arranged to form a separator zone Z in the interface between the inlet space, the material outlet space  1122  and the air outlet space. 
         [0057]    The material outlet space  1122  is situated at a lower vertical level than the separator zone Z, so that material separated from incoming material-laden airflow is conducted via the material outlet space  1122  to the metering device  109  with the aid of gravitational force. At substantially the same vertical level as the separator zone Z, the air outlet space  1123  can be arranged to connect to that duct  108  via which the drive airflow is fed to the metering device  109 . Alternatively, the air outlet space can, as shown, constitute part of the duct  108 . As a further alternative, the air outlet space  1123  can connect to the duct  108  via a return duct (not shown).The separator  1 ′ can be configured in accordance with the principles described with reference to  FIGS. 1-2 , but is here provided with a plurality of ribs  15 ′, which are distributed around the material flow direction and form gaps  12 ′ extending along the material flow direction. As can be seen from  FIG. 9   d , the separator  1 ′ can be placed relative to the drive air duct  108  such that the inner limit face of the drive air duct  108  intersects or tangents an inner face of the separator  1 ′. The body which is defined by the ribs  15 ′ can be slightly frustoconical. The ribs  15 ′ can have a cross section which tapers in the material flow direction FM and the gaps  12 ′ can thus have a gap width which increases in the material flow direction FM. 
         [0058]    The separator  1 ,  1 ′, comprising ribs  15 ,  15 ′ and flanges  14 ,  14 ′,  16 ,  16 ′, can be formed in one piece, for example by casting of a separator  1 ,  1 ′ of metal, or by injection moulding if the separator  1 ,  1 ′ is to be made of polymer material. If the body defined by the ribs  15 ,  15 ′ is slightly conical or frustoconical, this can facilitate removal of the separator  1 ,  1 ′ from a forming tool. Configuration of the ribs  15 ,  15 ′ with a cross section which tapers in the material flow direction FM can also facilitate removal of the separator from a forming tool. 
         [0059]    In the material outlet flange  16 ′ can be arranged axially continuous recesses  18 ′, so that the ribs connect to the edge portion  13   a ′ of the material outlet  13 ′ via respective spacer parts  18 ′. The ribs  18 ′ can thus connect to the edge portion  13   a ′ of the material outlet  13  at a larger radius than that at which the ribs connect to the edge portion  11  a′ of the material inlet  11 ′. 
         [0060]    In addition, the separator can have a portion  19 , which defines a part of the inlet space  1121 . The portion  18  can be formed in one piece with the separator  1 ,  1 ′. 
         [0061]    It will be appreciated that the herein shown separator and metering device can be used to dispense any chosen granular material within agriculture, such as seed, fertilizer or pesticide.