Abstract:
A metering conveyor adapted to move a controlled volume of grain. The conveyor incorporates a series of carriers that can each be switched between a scooper assembly and a blocker assembly. The ratio of scooper assemblies to blocker assemblies determines the volume of grain that is metered for a predetermined conveyor speed. The conveyor is modular and is especially suited for a modular rectangular grain dryer. The conveyor further includes a paddle that is adapted to move grain to a discharge chute.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to grain dryers and more particularly to a metering conveyor for use with grain dryers. 
     BACKGROUND OF THE INVENTION 
     Continuous flow grain dryers generally include a column of drain which flows by gravity between parallel perforated walls. Heated air is forced through the perforated walls, thereby drying the grain. A metering system is generally incorporated in the lower portion of the grain dryer. The metering system is typically coupled to a control system that controls the discharge rate of grain exiting the dryer. Typically, it is desirable to dry grain to a preselected moisture content for storage or use. In order to attain a target moisture content for grain discharged from a grain dryer, the grain discharge rate should be accurately controlled. 
     Modular rectangular grain dryers can be supplied in varying lengths to accommodate various volumetric flow rates of grain, depending upon demand. A single discharge within a modular grain dryer requires that the grain discharge or metering rate be adjustable for the modular dryers in order to ensure a uniform moisture content of grain that is dried. Typically, rectangular grain dryers utilize metering rolls with an auger beneath to meter the grain from the dryer. What is therefore needed is an adjustable discharge conveyor for a modular grain dryer. 
     SUMMARY OF THE INVENTION 
     In accordance with the teachings of the present invention, an adjustable conveyor for a grain dryer is disclosed. In one form, the present invention provides a grain dryer that includes spaced apart inner and outer walls defining a chamber for directing grain therethrough and further defining a grain discharge opening between lower edges of the walls. A horizontal shelf is disposed adjacent the discharge opening for receiving grain from the chamber and a trough is disposed below the shelf for receiving grain from the shelf. The grain dryer further includes a conveyor including a paddle configured to push grain through the trough in a second direction, a scooper assembly configured to travel in a first direction over the shelf and used to meter grain from the shelf to the trough, and a blocker assembly is configured to prevent grain flow from the discharge opening. 
     In another form, the present invention provides a grain dryer that includes spaced apart inner and outer walls defining a chamber for directing grain therethrough and further defining a grain discharge opening between lower edges of the walls. A horizontal shelf is disposed adjacent the discharge opening for receiving grain from the chamber and a trough disposed below the shelf for receiving grain from the shelf. A conveyor to move a carrier along a fixed path. The carrier is configured to accept a scooper bracket, or a blocker panel. A scooper bracket is used to meter grain from the shelf to the trough and a blocker panel is configured to prevent grain flow from the discharge opening. 
     In yet another form, the present invention provides a method of manufacturing a metering conveyor system that includes providing a drive mechanism having a plurality of carriers attached thereto, wherein each carrier is configured to attach to either a scooper panel or a blocker panel, selecting a distance between a plurality of scooper panels, attaching the plurality of scooper panels to the drive mechanism at intervals equal to the selected distance, and attaching at least one blocker panel to the drive mechanism between the plurality of scooper panels. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of a modular rectangular grain dryer; 
     FIG. 2 is a top partial view of a conveyor in accordance with the teachings of the present invention; 
     FIG. 3 is a side view of the conveyor of FIG. 2, shown with some scooper assemblies and blocker assemblies removed for clarity; 
     FIG. 4 is a perspective view of a portion of the conveyor of FIG. 2, showing the relative position of scooper assemblies and blocker assemblies; 
     FIG. 5 is a perspective view of a scooper assembly of the conveyor of FIG. 2; and 
     FIG. 6 is a perspective view of a blocker assembly of the conveyor of FIG.  2 ; 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Moreover, while the present invention is described in detail in reference to a grain dryer, it is envisioned that the present invention is not limited to a grain dryer but also may be used in any other application that requires a metering conveyor for granular particles. 
     With initial reference to FIG. 1, a grain dryer in accordance with the teachings of the present invention is shown and generally indicated by the reference numeral  10 . Grain dryer  10  includes an outer housing  12  configured to allow air to pass therethrough, an inner housing  14  configure to allow air to pass therethrough, a fan  16 , a heater  18 , a control system  20 , and a conveyor  30 . Outer housing  12  is shown to include an upper portion  32 , and a lower portion  34  with a shelf  36  extending therefrom. Inner housing  14  is shown in FIGS. 1 and 2 to include an upper portion  38  and a lower edge  40 . Outer housing  12  and inner housing  14  define a column  42  that defines a grain flow path. Lower edge  40  of inner housing  14  and shelf  36  define a discharge opening  44  extending along the length of inner housing  14 . 
     As presently preferred, grain dryer  10  is provided in a modular assembly wherein outer housing  12  and inner housing  14  are provided in about 2-foot sections. Each section added to a modular grain dryer  10  proportionally increases the volumetric capacity of the dryer. Conveyor  30  is provided as a modular assembly wherein portions can be added or removed to accommodate differing lengths of grain dryer  10 , as discussed below. In this manner, grain dryer  10  provides a modular apparatus for drying grain that may be sized to accommodate various desired volumetric flow rates. 
     With reference to FIGS. 2,  3 , and  4 , discharge conveyor  30  is shown to include a trough  46 , and a discharge chute  48 . Conveyor  30  further includes a drive mechanism, or chain,  100  including a plurality of links  102  engaging a first sprocket  104  and a second sprocket  106 . Conveyor  30  is further shown to include a plurality of base assemblies  110 . Base assemblies  110  include a carrier  114  coupled to chain  100  and a paddle  118 . Each carrier  114  is shown to include two sides  116 . As best seen in FIG. 5, a scooper assembly  120  includes a base assembly  110 , a scooper bracket  122  attached to each side  116 , and a scooper panel  124 . As seen in FIG. 6, a blocker assembly  130  includes a base assembly  110 , a blocker bracket  132  attached to each side  116 , and a blocker panel  134 . In the embodiment illustrated, carrier  114 , scooper bracket  122  and blocker bracket  132  are constructed of 14 gauge galvanized steel, and paddle  118 , scooper panel  124 , and blocker panel  134  are constructed of {fraction (3/16)} inch ultra high molecular weight (UHMW) polyethylene 
     As best seen in FIGS. 3 and 4, shelf  36  includes cutouts  138  to allow grain to fall from the level of shelf  36  to the trough  46 . As discussed below, the scooper brackets  122  and the scooper panels  124  direct grain from discharge opening  44  to cutouts  138 . 
     When assembled, conveyor  30  is shown in FIGS. 2 and 3 to include the chain  100  of links  102  that cycle around sprockets  104 ,  106 . Because of the use of a continuous chain  100 , the carrier  114  is carried in a first direction and then in a second direction which is generally opposite the first direction. At least a portion of the links  102  provide a locating position for carriers  114  to attach thereto. A carrier  114  is attached to a link  102  about every foot along the length of chain  100 . Each carrier  114  is configured to be a portion of either a scooper assembly  120  or a blocker assembly  130 . Thus provided, carriers  114  provide a selection of possible locating distances between scooper brackets  122  attached to different carriers  114 . The carriers  114  that are not desired to act as scooper assemblies  120  are adapted to be blocker assemblies  130 . In this manner, conveyor  30  provides a metering conveyor system that will scoop a predetermined amount of grain from shelf  36  that is generally proportional to the amount of selected scooper assemblies. 
     In operation, blocker panels  134  prevent grain from moving from discharge opening  44  to cutouts  138 . Scooper panels  124  and scooper brackets  122  peel a predetermined volume of grain from discharge opening  44  and direct the grain to cutouts  138 . The volume of grain moved by one scooper panel  124  depends upon variables such as the linear speed of conveyor  30 , the height of grain on shelf  36 , and the width of grain that the scooper panel  124  removes from shelf  36 . The linear speed of conveyor  30  may be adjustable with control system  20 . The height of grain removed from shelf  36  is determined by the height of discharge opening  44  and the proximity of scooper panel  124  to discharge opening  44 . The width of grain removed from shelf  36  by one scooper panel  124  is the width of the grain that is pushed toward cutouts  138  by the scooper panel  124 . As presently preferred, scooper panel  124  is positioned at an acute attack angle relative to the direction of chain  100  movement, and more preferably at an attack angle of less than about 45°. 
     As best seen in FIG. 2, conveyor  30  is configured such that scooper panels  124  divert grain from discharge opening  44  to trough  46  as carriers  114  cycle in a first direction, or away from discharge chute  48 . Blocker panels  134  prevent grain from passing from discharge opening  44  to trough  46 . In this manner, blocker assemblies  130  inhibit the flow of grain from shelf  36  to trough  46 . 
     As best seen in FIG. 3, paddles  118  are configured to push grain through trough  46  as carriers  114  cycle in a second direction opposite the first direction, or toward discharge chute  48 . As carriers  114  rotate about first sprocket  104 , paddles  118  push grain from trough  46  into discharge chute  48 . In this manner, conveyor  30  is configured to cycle in a fixed path, or continuous loop, and to direct the metered grain from shelf  36 , to trough  46 , and to a discharge  48 . 
     When different sizes of dryers are provided, e.g. as a result of using more or fewer 2-foot grain dryer sections, the ratio of scooper assemblies to blocker assemblies may be changed as appropriate. To accomplish this change, scooper brackets  122  or blocker brackets  132  are detached from carriers  114  and the desired number of scooper brackets  122  or blocker brackets  132  and blocker panels  134  are coupled to the carriers  114 . As best seen in FIGS. 5 and 6, both scooper brackets  122  and blocker brackets  132  are removably attached to carriers  114  with fasteners  140 . As presently preferred, fasteners  140  are stainless steel bolts having complementary nuts attached thereto. 
     As presently preferred, carriers  114  are about one foot in length such that a carrier  114  is coupled to chain  100  about every 12 inches. A 20 foot grain dryer would include ten 2-foot sections of housing, 25 blocker assemblies  130 , and 24 scooper assemblies  120 . While FIGS. 2 and 3 depict the conveyor  30  with an approximate ratio of 2 blocker assemblies  130  to one scooper assembly  120 , it is envisioned that this ratio can be any range of ratios required to accommodate a preselected volumetric flow rate. As will be appreciated, the speed of carriers  114  as they cycle through conveyor  30  can be altered to achieve a different grain flow rate. It is envisioned that a more consistent discharge rate is accomplished when the scooper assemblies  120  are evenly distributed along chain  100 . 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the sprit and scope of the invention.