Abstract:
An apparatus for use in the drying of grain and more particularly but not exclusively, to a grain storage bag having grain drying capabilities, includes an elongate flexible container having an air inlet arrangement and an air outlet arrangement, with the air inlet arrangement being in flow communication with the air outlet arrangement through an internal volume of the container. The apparatus also includes fluid displacement elements for causing airflow from the air inlet arrangement to the air outlet arrangement.

Description:
BACKGROUND TO THE INVENTION 
     THIS invention relates to an apparatus for use in the drying of grain and more particularly but not exclusively, to a grain storage bag having grain drying capabilities. 
     In the specification the term grain should be interpreted to include a variety of harvested crops that are found in agriculture, including but not limited to cereal grains, grain legumes and oilseeds. 
     Grain drying, as used in this specification, refers to the removal of some of the moisture from grain by mechanically moving air through the grain after it has been harvested. Grain in the field dries naturally as the crop matures, giving up moisture to the air until the grain moisture is in equilibrium with the moisture in the air. However, grain often needs to be dried even further after harvesting before it can be delivered to the market. If no drying facility is available the harvesting process may come to a standstill, which in turn adversely influences production cost and the planting of a next batch of crop. 
     A number of grain drying methods and apparatuses have been proposed in the past, and include drying floors, bin-type dryers, drying wagons and drying cribs and solar dryers. However, these methods all have disadvantages associated therewith, including the high capital cost of the drying facilities, the complicated nature of some of the drying facilities, and the limited control associated with some of the drying facilities. 
     It is accordingly an object of the invention to provide an apparatus for use in drying grain that will, at least partially, alleviate the above disadvantages. 
     It is also an object of the invention to provide an apparatus for drying grain which will be a useful alternative to existing grain drying facilities. 
     SUMMARY OF THE INVENTION 
     According to the invention there is provided an apparatus for use in drying grain, the apparatus including:
         an elongate flexible container suitable for receiving grain, the container being at least partially sealable once grain has been introduced therein;   the container having an air inlet arrangement, and an air outlet arrangement, with the air inlet arrangement being in flow communication with the air outlet arrangement through an internal volume of the container; and   fluid displacement means for facilitating airflow from the air inlet arrangement to the air outlet arrangement.       

     There is provided for the flexible container to be in the form of an elongate cylindrical container, and for the air inlet arrangement and the air outlet arrangement to be located towards opposing sides of the container. 
     The air inlet arrangement may be in the form of a header that extends adjacent a side of the container, the header having at least one inlet that is in flow communication with the fluid displacement means, and a plurality of outlets that are in flow communication with the internal volume of the container. 
     Preferably, a longitudinal axis of the elongate container is horizontal, and the header is substantially parallel to the longitudinal axis of the container. 
     The air inlet arrangement may be located at a distal zone of the header, and may alternatively be located at a proximal zone of the header. There is also provided for the air inlet arrangement to include a plurality of inlets. 
     The outlets of the air inlet arrangement may be defined by a plurality of apertures in the header that overlie corresponding apertures in the sidewall of the container. 
     The air outlet arrangement may be in the form of a plurality of apertures provided in a sidewall of the container opposite the sidewall where the inlet arrangement is located. 
     In another embodiment, the air outlet arrangement may be in the form of a collecting header that extends adjacent a side of the container opposite the side where the air inlet arrangement is located, the header having a plurality of inlets which are in flow communication with the internal volume of the container, and an outlet which is in flow communication with the environment. The inlets of the air outlet arrangement may be defined by a plurality of apertures in the header that overlie corresponding apertures in the sidewall of the container. 
     There is provided for the container to be in the form of an elongate bag, and more particularly a polymeric silo bag. 
     The air displacement means is preferably in the form of a fan. 
     A heater may also be provided to heat the air being displaced into the container. 
     A further embodiment of the invention provided for the air inlet arrangement to be in the form of a plurality of air inlet pipes extending longitudinally into the container, and for the air-outlet arrangement to be defined by one or more apertures provided in an upper wall of the container. 
     The air inlet pipes may include apertures in sidewalls thereof, which apertures are in flow communication with an internal volume of the container. Open ends of the pipes may be in flow communication with a fluid displacement means. 
     A still further embodiment of the invention provides for the air inlet arrangement to be in the form of a plurality of air supply pockets located below the container, the air supply pockets having inlets that are in flow communication with a fluid displacement means, and outlets that are in flow communication with an internal volume of the container. 
     Inflatable lifting pockets may be provided in-between air supply pockets, and will serve to displace the bottom wall of the container upwardly. 
     According to a further aspect of the invention there is provided a method of drying grain, the method including:
         providing an elongate flexible container suitable for receiving grain, the container being at least partially sealable once grain has been introduced therein, and the container having an air inlet arrangement, and an air outlet arrangement, with the air inlet arrangement being in flow communication with the air outlet arrangement through an internal volume of the container;   filling the container with grain; and   inducing airflow from the air inlet arrangement to the air outlet arrangement.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred embodiment of the invention is described by way of a non-limiting example, and with reference to the accompanying drawings in which: 
         FIG. 1  is a cross-sectional end view of the apparatus in accordance with one embodiment of the invention; 
         FIG. 2  is a cross-sectional plan view of the apparatus of  FIG. 1 ; and 
         FIGS. 3 a  to 3 c    are schematic illustrations of a number of alternative inlet configurations for the apparatus of  FIGS. 1 and 2 . 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     Referring to the drawings, in which like numerals indicate like features, a non-limiting example of an apparatus for drying grain in accordance with the invention is generally indicated by reference numeral  10 . 
     With reference to  FIGS. 1 and 2 , the apparatus  10  comprises a container  20 , which is in the form of an elongate flexible bag, which is made of a suitable polymeric material. The container is similar to storage bags already known in the trade, and which are sometimes referred to as silo bags. The detail design of the bag, as well as the loading and unloading of theses bags are not relevant to the invention. 
     The container  20  is cylindrical in nature, and comprises a continuous sidewall. For the purposes of clarity, reference will however be made to a first end  21 , a second end  22 , a first sidewall  23 , a second sidewall  24 , a bottom wall  25  and an upper wall  26 . The container differs from similar containers found in industry, in that a plurality of inlet apertures  27  are provided in the first sidewall  23 , and a plurality of outlet apertures  28  are provided in the second sidewall  24 . The apertures on each side is aligned in a linear configuration, and a centerline through the apertures are generally parallel to a longitudinal axis of the container. 
     An air inlet arrangement  30  is provided adjacent the first sidewall  23  of the container  20 . The air inlet arrangement  30  is in the form of an elongate tubular header  31  that extends along at least part of the length of the container  10 . The header  31  has at least one inlet  32  which is in flow communication with a fluid displacement means  50 , which is typically in the form of a fan. The inlet(s) can be closed off when there is no air flow through the system, so as to prevent the unwanted ingress of moisture and contaminants. The inlet configuration may differ, and is described in more detail below. A plurality of outlets  33  are provided in a sidewall of the header  31 , and are configured and dimensioned to overlie the inlet apertures  27  provided in the container, thus bringing the header in flow communication with an internal volume of the container  10 . 
     An air outlet arrangement  40  is provided adjacent the second sidewall  24  of the container  20 . The air outlet arrangement  40  is also in the form of an elongate tubular header  41  that extends along at least part of the length of the container  10 . The header  41  has at least one outlet  42  which is in flow communication with the environment. The outlet(s) can be closed off when there is no air flow through the system, so as to prevent the unwanted ingress of moisture and contaminants. A plurality of inlets  43  are provided in a sidewall of the header  41 , and are configured and dimensioned to overlie the outlet apertures  28  provided in the container, thus bringing the header in flow communication with an internal volume of the container  10 . 
     In use, the container  10  will be loaded with grain  11  to be dried and stored. The inlet  32  of the air inlet arrangement  30  will be opened, as will the outlet  42  of the air outlet arrangement  40 , so as to define a flow passage from the air inlet arrangement  30  through the internal volume of the container  20  and into the outlet arrangement  40 . When the fan  50  is activated, dry air will be forced through the container  20 , and more particularly will be forced past the grain  11  inside the container. The air may be ambient air, but may also be heated by way of a heater (not shown). The air flow will result in the removal of moisture from the grain in a convective manner. Once a desired dryness has been achieved the fan  50  will be stopped, and the inlet  32  of the inlet arrangement  30 , as well as the outlet  42  of the outlet arrangement  40  will be closed. 
     A number of inlet configurations are shown in  FIGS. 3 a  to 3 c   , and entails an inlet at one distal end ( FIG. 3 a   ), an inlet at a proximal zone ( FIG. 3 b   ) which will also entail the use of a distribution plenum  51 , and a plurality of inlets along the length of the header ( FIG. 3 c   ). 
     In is envisaged that the container may first be filled with grain, and that the air inlet arrangements will only be mounted on and secured to the container after the container has been filled with grain. 
     It is foreseen that other configurations may also be used to achieve the same result, which is to dry grains in an elongate flexible container. For example, the inlet arrangement may be in the form of a plurality of perforated pipes that extends longitudinally into the container, and which are located towards a bottom zone of the container. In this case the outlet arrangement will be at the top of the container, resulting in air flow in a vertical, upwardly direction. In a further example, the inlet arrangement may be in the form of a number of air supply pockets located immediately below the container, and which supply air through apertures in the container that corresponds with openings in the air supply pockets. In this embodiment it will be necessary to lift the bag and its contents in order to prevent the air supply pockets from collapsing, and lifting pockets will therefore be provided. The lifting pockets will not have outlets, thus enabling them to be inflated and to act as lifting cushions. 
     It will be appreciated that the above is only one embodiment of the invention and that there may be many variations without departing from the spirit and/or the scope of the invention.