Apparatus to process grain received from a dryer

Abstract

A grain tower, including a silo; a false bottom including alternating upward slanted portions and downward slanted portions; a plurality of ventilation openings adapted to allow air to pass through, but not grain to pass through; and a plurality of extraction openings adapted to extract grain from the silo.

Claims

1. A grain tower comprising: a silo; a false bottom including alternating upward slanted portions and downward slanted portions; a plurality of ventilation openings adapted to allow air to pass through, but not grain to pass through; a plurality of extraction openings adapted to extract grain from the silo; a plurality of joining pieces with one each located at a pair of the plurality of extraction openings to direct the grain to a drop tube, wherein one of the pair of the plurality of extraction openings is located in one of the upward slanted portions and another of the pair of the plurality of extraction openings is located in one of the downward slanted portions that is adjacent to the one of the upward slanted portions.

2. The grain tower of claim 1 further comprising, a plurality of gates with one each adapted to control the flow of grain through a respective one of the plurality of joining pieces.

3. The grain tower of claim 1, wherein the false bottom has a sawtooth pattern where the upward slanted portions and the downward slanted portions are generally planar.

4. The grain tower of claim 1, wherein the false bottom is defined by a plurality of elongated sections that are arranged side edge to side edge.

5. The grain tower of claim 1, wherein each drop tube direct the grain to an extractor.

6. The grain tower of claim 1 further comprising, a plurality of gates with one each adapted to control the flow of grain through a respective one of the plurality of joining pieces.

7. The grain tower of claim 6 wherein the plurality of gates can move between an open position and a closed position.

8. The grain tower of claim 1, further comprising an extraction system comprising a plurality of extraction inlets, wherein each of the plurality of extraction openings is adapted to feed grain to one of the plurality of extraction inlets.

9. The grain tower of claim 8, wherein the extraction system comprises a plurality of extractors.

10. The grain tower of claim 9, wherein each of the plurality of extractors includes a plurality of extraction inlets and a same number of extraction inlets as extraction openings.

11. The grain tower of claim 1, wherein a cross section of the grain tower is rectangular.

12. The grain tower of claim 1 further comprising, a Y-shaped drop tube coupled to a pair of the plurality of extraction openings to direct the grain to an extractor.

13. The grain tower of claim 12 further comprising, a plurality of gates with one each adapted to control the flow of grain through a respective one of the pairs of the plurality of joining pieces.

14. A grain tower, comprising: a silo; a false bottom including alternating upward slanted portions and downward slanted portions; a plurality of ventilation openings adapted to allow air to pass through, but not grain to pass through; a plurality of extraction openings adapted to extract grain from the silo; and a plurality of joining pieces with one each located at each of the plurality of extraction openings to direct the grain to a drop tube; wherein: pairs of the plurality of joining pieces are oriented adjacent to each other such that one of the pairs is joined to one of the upward slanted portions and another of the pairs is joined to one of the downward slanted portions that is directly adjacent to the one of the upward slanted portions, and each of the plurality of joining pieces includes one of the plurality of extraction openings to direct the grain to a Y-shaped drop tube.

15. The grain tower of claim 14, wherein the false bottom has a sawtooth pattern where the upward slanted portions and the downward slanted portions are generally planar.

16. The grain tower of claim 14, wherein the false bottom is defined by a plurality of elongated sections that are arranged side edge to side edge.

17. The grain tower of claim 14 further comprising, a drop tube coupled to each of the plurality of extraction openings to direct the grain to an extractor.

18. The grain tower of claim 14 further comprising, a plurality of gates with one each adapted to control the flow of grain through a respective one of the plurality of joining pieces.

19. The grain tower of claim 18 wherein the plurality of gates can move between an open position and a closed position.

20. The grain tower of claim 14, further comprising an extraction system comprising a plurality of extraction inlets, wherein each of the plurality of extraction openings is adapted to feed grain to one of the plurality of extraction inlets.

21. The grain tower of claim 20, wherein the extraction system comprises a plurality of extractors.

22. The grain tower of claim 21, wherein each of the plurality of extractors includes a plurality of extraction inlets and a same number of extraction inlets as extraction openings.

23. The grain tower of claim 14, wherein a cross section of the grain tower is rectangular.

24. The grain tower of claim 14 further comprising, a Y-shaped drop tube coupled to a pair of the plurality of extraction openings to direct the grain to an extractor.

25. The grain tower of claim 14 further comprising, a plurality of gates with one each adapted to control the flow of grain through a respective one of the pairs of the plurality of joining pieces.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) To facilitate understanding of the invention, for illustrative but not limitative purposes, below is a description of an embodiment of the invention that makes reference to a series of figures.

(2) FIG. 1 is a block diagram of a grain tower according to an embodiment of the present invention.

(3) FIG. 2 is a block diagram of the grain tower of FIG. 1 showing a transition zone at an upper limit.

(4) FIG. 3 is a block diagram of the grain tower of FIG. 1 showing a transition zone at a lower limit.

(5) FIG. 4 is a block diagram of a control system according to an embodiment of the present invention.

(6) FIG. 5 is an image of a rotary extractor, with a portion of the housing around the auger removed.

(7) FIG. 6 is a block diagram of a grain tower according to another embodiment of the present invention.

(8) FIG. 7 is a top view of a perforated false bottom, according to one embodiment.

(9) FIG. 8 is a cross-section view of the perforated false bottom and the extraction system taken along cut line A-A′ of FIG. 7.

(10) FIG. 9 is a top view of the extraction system without the perforated false bottom.

(11) FIG. 10 is closer view of a cross-section view of the perforated false bottom.

(12) FIGS. 11A and 11B are views showing a gate.

(13) FIG. 12 is a top view of a perforated false bottom, according to another embodiment.

(14) FIG. 13 is a cross-section view of the perforated false bottom and the extraction system taken along cut line B-B′ of FIG. 12.

(15) FIG. 14 is a top view of a perforated false bottom, according to another embodiment.

(16) FIG. 15 is a cross-section view of the perforated false bottom and the extraction system taken along cut line C-C′ of FIG. 14.

(17) The figures make reference to a set of elements, namely: 1. tower 2. inlet 3. extractor 3A. extraction system 4. ventilation system 5. false bottom 5A. non-planar false bottom 6. controller 7. first temperature sensor 8. second temperature sensor 9. first level detector 10. second level detector 11. nozzle 12. grain outlet temperature sensor 13. grain inlet temperature sensor 14. drop tube 14A. Y drop tube 15. perforated slat 15A. downward slanted plate 15B. upward slanted plate 16. joining piece 16A. dual joining piece 17. conveyor 20. opening 22. gate 1F. first stage 2F. second stage 3F. third stage 4F. fourth stage ASPn. top ventilator S3. inlet S4. outlet VTn. bottom ventilator ZT. transition zone

DETAILED DESCRIPTION OF THE EMBODIMENTS

(18) An embodiment of this disclosure is a method for processing grain extracted from a dryer, of the kind that performs slow, deferred, and continuous cooling, and extraction of the grain's residual moisture.

(19) With reference to FIG. 1, a method for processing grain includes the following operations at different stages or portions in a direction, in a single structure, silo, or tower 1:

(20) Loading the grain discharged from the dryer through an inlet 2 in a portion of the tower 1 at a first stage F1. The tower can have a cross-section that is circular or square or rectangular, as represented in FIGS. 6-9. Using a single rotary extractor 3, similar to the one shown in FIG. 5, to extract the grain from the center of a silo, i.e., tower with a circular cross section, and limit the size of a cylindrical tower and, therefore, its capacity. For example, the diameter of a cylindrical tower may not be able to exceed 8.4 m at a capacity of 36 Tm/h. It has been discovered that utilizing a new extraction strategy greatly increases the capacity available with a tower and can be more suitable for larger installations.

(21) In the first stage F1, the grain is transferred from an outlet in the dryer to the tower 1 by flowing the grain through the inlet 2 at a portion of the tower 1. This process takes into account the status of the exterior dryer, from which the grain to be processed is discharged, as “master” of the process, that is, the dryer output regulates the entry of grain into the tower 1 considering the grain temperature as provided by an inlet temperature sensor 13. This is why it must be assured that the capacity of the tower 1 for processing grain exceeds the quantity transferred from the dryer at all times.

(22) Resting and homogenizing the grain, in which the water contained inside the grain is displaced by capillary action to the outside of the grains, at a second stage 2F.

(23) The second stage F2 is where rest and homogenization, in a second portion of the tower 1, of the hot grain occurs with the residual moisture coming from the first stage F1. The grain is left for a period of “rest” (known as “tempering” among those knowing cereal production), also known as homogenization, in which the internal gradients of the grain are canceled out, as discussed above, migrating its heat and its moisture.

(24) Cooling and drying, in which the grain is cooled and dried by directed and intermittent forced ventilation air, with the ventilation air at a ventilation temperature, at a third stage 3F. This forced ventilation air is provided by a ventilation system 4 that blows cooled ventilation air into the grain. The ventilation air forced through the grain can be discharged to the exterior, once the additional cooling and drying of the grain is done, through a nozzle 11 located in a portion of the tower 1.

(25) Discharge of the dried and cooled grain, now ready for subsequent processing, such as cleaning by aspiration of the fine particles that accompany the grain that are often produced in the third stage, by an extractor 3 at a fourth stage 4F.

(26) In this method, the second stage 2F and the third stage 3F are separated by a dynamic transition zone ZT that is moved through the inside of the tower 1. The transition zone ZT is driven in an input direction (e.g., upward or right) by the ventilation air from the ventilation system 4, and in an opposite output direction (e.g., downward or left) by the extractor 3. Both the ventilation system 4 and the extractor 3 can be located adjacent to each other in the tower 1 and are controlled by a controller 6. In the transition zone ZT is where the greatest exchange of heat occurs between the grain and the ventilation air provided by the ventilation system 4. Preferably, the transition zone ZT will have a thickness within the volume of the grain of approximately one meter.

(27) As shown in FIG. 1, the transition zone ZT is preferably located between a first position (e.g., upper), in which an upper temperature sensor 7 is located, and another position (e.g., lower), in which a lower temperature sensor 8 is located. These temperature sensors 7 and 8 are connected to the controller 6, such that, when the transition zone ZT reaches the upper position, the upper temperature sensor 7 sends a control signal to the controller 6 that stops the ventilation system 4 to stop the temperature of the grain above that point from decreasing.

(28) When the transition zone ZT reached the first limit, as shown in FIG. 2, the transition zone ZT of grain with a similar temperature can be driven in an output direction by the extractor 3. The extractor 3 removes volume of cooled grain from the tower 1 outside the transition zone ZT and effectively moves the grain in the transition zone ZT. Conversely, when the transition zone ZT reaches the second position, as shown in FIG. 3, the lower temperature sensor 8 sends a signal to the controller 6 to stop the extractor 3. The ventilation system 4 and the extractor 3 are designed such that, when they are both activated, the transition zone ZT will receive a net movement and will slowly move.

(29) Thus, the movement of the transition zone ZT can be alternating, between two “limits,” which are the first and the second lower temperature sensors 7 and 8, where movement in an input direction will be caused by the ventilation system 4, and movement in an output direction will be caused by the extractor 3, all monitored and controlled by the controller 6.

(30) In other words, the ventilation air driven by the ventilation system 4 is activated intermittently by the controller 6, as described above, moving the transition zone ZT in a direction. The extractor 3 is activated intermittently by the controller 6 moving the transition zone ZT in the opposite direction. Thus controlling the location of the transition zone ZT allows the ratio of the volumes occupied by the grain to be graduated, thereby improving the efficiency of the resting and homogenizing process.

(31) Preferably, the loading of the grain in the tower 1 is controlled by the controller 6, through first level detector 9 and a second level detector 10, both located in a portion of the tower 1, as shown in FIG. 1. These level detectors 9 and 10 are connected to the controller 6 such that the first level detector 9 sends a signal to the controller 6 when the grain level reaches the first level detector 9, whereupon the controller 6 stops the grain input into the tower 1. Also, the second level detector 10 sends a signal to the controller 6 when the grain level reaches the second level detector 10, whereupon the controller 6 activates the grain input in the tower 1. The controller 6 sends signals to start and stop a grain conveyor (not shown) that transfers the grain from the dryer to the inlet 2 to control the grain quantity in the tower 1. In this way, the loading of grain in the tower 1 is automated by the two-level detectors 9 and 10.

(32) The grain temperature at the inlet 2 can be between 55-65° C. as measured by temperature sensor 13. Preferably, the intake conditions of the grain into the tower 1 in the first stage F1 of loading are temperature of about 60° C. and moisture content at about 17.7%.

(33) In addition, the grain temperature at the extractor 3 can be between 0-15° C. as measured by the grain outlet temperature sensor 12. Preferably, in the fourth stage F4 of discharge, the grain exits the tower 1 at a temperature of about 10° C. and with moisture at about 15%.

(34) Another embodiment of the present invention includes an apparatus to process grain received from a dryer, of the kind that performs slow, deferred, and continuous cooling, and extraction of the grain's residual moisture, in which the grain-processing method described previously is carried out.

(35) As the figures show, the apparatus can include a single tower 1, which in turn has an inlet 2 one portion to receive grain extracted from an external dryer, and an extractor 3 in another portion of the tower 1 to discharge the grain once it has been cooled and the moisture has been extracted. Also, the apparatus can include a ventilation system 4 that provides ventilation air to cool the grain. The extractor 3 and the ventilation system 4 can be located in the same (e.g. bottom) portion of the tower 1, and the ventilation system 4 can be situated below a false bottom 5 of the tower 1. Both the extractor 3 and the ventilation system 4 are controlled by the controller 6, which intermittently activates and stops them during the processing of the grain, as previously described.

(36) The ventilation system 4 can include temperature and humidity conditioning to heat or cool and adjust the moisture content of the intake air to the ventilation system 4 to predetermine ranges before forcing the ventilation air into the tower 1.

(37) FIG. 4 is a block diagram of a control system according to an embodiment of the present invention. As shown and previously described, the control system controls movement of the grain through the tower 1 and operation of rest and homogenization process. As shown, the control system can include a controller 6 that is in electronic communication with the extractor 3, the ventilation system 4, the first temperature sensor 7, the second temperature sensor 8, the first level detector 9, the second level detector 10, the grain outlet temperature sensor 12, and the grain inlet temperature sensor 13.

(38) In an operating cycle the controller 6 can make periodic measurements or provide continuous monitoring of the various temperature and position sensors. For example, measurement can be taken for about a minute within a 10 to 20 minute interval. As previously described, grain enters the tower 1 from a dryer through the inlet 2. When grain reaches the first level detector 10, the controller 6 activates the ventilation system 4 to generate and output ventilation air into the tower 1 through the false bottom 5. The temperature of the grain in the second phase 2F does not vary much while the moisture contained in the grain is migrating from the core to the outside. In the third phase 3F, there is a more rapid cooling of the grain because it is exposed to a greater amount of air and is closer to the ventilation air.

(39) In operation, the controller 6 works to maintain the following temperature conditions:

(40) $T_1=T_h-T_{i1}\mathrm{must}\mathrm{be}\le 10°C.T_2=T_{i2}-T_s\mathrm{must}\mathrm{be}\ge 15°C.$ Where: T.sub.h is the grain inlet temperature measured at the grain inlet temperature sensor 13, and can vary between 55-65° C.; T.sub.i1 is a first intermediate temperature of the transition zone and measured at the upper temperature sensor; T.sub.i2 is a second intermediate temperature of the transition zone and measured at the second temperature sensor 8; and T.sub.s is the grain outlet temperature measured at the grain outlet temperature sensor 12, and can be in a range of 0−15° C.

(41) The controller 6 continually operates according to the following cycle while measurements are made of the various position and temperature sensors in the tower 1 for approximately 1 minute every 10-20 minutes of operation. The grain enters the tower 1 from the dryer via the inlet 2. When the grain reaches the second level sensor 10, the ventilation system 4 starts to work. In the second phase F2 of the tower 1, the grain's temperature does not vary much and the moisture contained in it is leaving the core to the exterior surface of the grain. In the third phase 3F of the tower 1, there is a greater cooling of the grain due to the ventilation air. After operating for a period of time, about 10-20 minutes, the grain processing, including the inlet 2, the extractor 3, and the ventilation system 4, is stopped so that measurements can be performed.

(42) If T.sub.1 is ≤15° C. and T.sub.2 is ≥15° C., the controller 6 controls the extractor 3 to start working. If T.sub.s is ≤15° C. and T.sub.1 and T.sub.2 are not met, the controller 6 controls the extractor 3 and the ventilation system 4 to work at the same time so that grain is discharged and so that, at the same time, the grain located in the third phase 3F is cooling down, moving the transition zone away from the extractor 3. In the event that neither T.sub.2 nor T.sub.s are met, the controller 6 will control the ventilation system 4 to work, which will move the transition zone away from the extractor 3. After the activity time has elapsed, the measurements will be performed again, repeating the process.

(43) FIG. 6 shows an apparatus to process grain received from a dryer according to another embodiment of the present invention. As shown, the apparatus can include a single tower 1 having a polygonal (e.g., rectangular, square, pentagon, hexagon, etc.) cross section, which in turn has an inlet S3 to receive grain extracted from an external dryer at a top portion of the tower 1, and an outlet S4 from an extraction system 3A in a bottom portion of the tower 1 to discharge the grain once it has been cooled and the moisture has been removed. Also, the apparatus can include a ventilation system that provides ventilation air to cool the grain and a false bottom 5.

(44) FIG. 6 shows that the ventilation system can include bottom ventilators VT1-VT4 that can be located below the false bottom 5 to blow cooling air up into the grain, as previously described. The ventilation system can additionally include top ventilators ASP1-ASP4 located on the roof of the tower 1 that suction air out of the tower 1 to increase the flow rate of the cooling air through the grain. Preferably, each top and bottom ventilator can be a same type of centrifugal fan, but any suitable fan or blower can be used. For example, an embodiment including only bottom ventilators can have an air flow rate of 40 m.sup.3/h/m.sup.3 of grain. Including top ventilators can increase the airflow rate to reach up to 60 m.sup.3/h/m.sup.3. Thus, the top ventilators significantly increase the capacity of the tower as the cooling process is accelerated. Including top ventilators to provide aspiration in the upper zone of the tower allows for faster venting of humid air above the grain and accelerates cooling of the grain.

(45) Although FIG. 6 shows a number of four each for the bottom ventilators VT1-VT4 and the top ventilators ASP1-ASP4, any number of each top and bottom ventilators can be configured while considering the geometry and capacity of the tower to cool a particular grain. Although it is preferred that the bottom ventilators VT1-VT4 and the top ventilators ASP1-ASP4 are controlled by the controller 6 to operate at the same time, it is possible that the top ventilators ASP1-ASP4 can be controlled separately from the bottom ventilators VT1-VT4. Optionally, any of the ventilators can be individually controlled to manage the airflow.

(46) In some embodiments there are more bottom ventilators. In some embodiments, there are more top ventilators. In some embodiments, there are the same number of top and bottom ventilators.

(47) FIG. 7 is a top view of the perforated false bottom 5A, according to one embodiment, showing the perforated slats 15 as elongated portions arranged side edge to side edge, and openings 20. FIG. 7 also shows ends of the extractors 17, the majority of which are hidden below the perforated false bottom 5A but can be seen in FIG. 9 where the false bottom 5A has been removed.

(48) FIG. 8 is a side section view of one configuration of a perforated false bottom 5A taken along cut line A-A′ of FIG. 7. The non-planar false bottom 5A is defined as having a sawtooth shape with a series of peaks and valleys. As shown in FIG. 8, going left to right, the first plate 15A is downward slanted, while the second plate 15B is upward slanted and they continue to alternate across the non-planar false bottom 5A. Depending on the angle, this shape effectively doubles the surface area of the false bottom compared to a one having a flat or planar shape and allows for a greater passage of cooling air from the ventilators below. FIG. 10 is a closer side view of the false bottom 5A including a downward slanted plate 15A and a second, upward slanted plate 15B. In some embodiments, angles 8 and w between the downward slanted plates 15A and the upward slanted plates 15B can be about 45 degrees. In some embodiments, the angles ω and θ can each independently range from 25 degrees to 90 degrees, or from 30 to 80 degrees, or 35 to 75 degrees, or 40 to 60 degrees, or any combination thereof. Alternatively, angles between peaks w and valleys θ can be different across the false bottom 5A. Alternatively, the locations where the downward slanted plates 15A and the upward slanted plates 15B come together can be rounded. In some embodiments, as shown in FIG. 10, a length along one of the upward or downward slanted plates 16a, 16b can be about 50 cm. In some embodiments, the length along the upward and downward slanted plates 15A, 15B can independently be 10 to 150 cm, or 20 to 125 cm, or 30 to 100 cm, or 40 to 75 cm, or any combination thereof. The valleys of the false bottom 5A focus the grain to a series of drop tubes 14 that direct the grain to the extraction system 3A like that shown in FIG. 8. In particular, as shown in FIG. 7, some sections of the false bottom 5A include extraction openings 20.

(49) The false bottom 5A can be made up of multiple perforated slats 15 with vent holes that allow the cooling air to flow through but not the grain. In some embodiments, these vent holes can be 1 to 2 mm in diameter. In some embodiments, the vent holes are less than 1.9 mm in diameter, or less than 1.8 mm in diameter, or less than 1.7 mm in diameter. In some embodiments, the vent holes are at least 1.1 mm in diameter, or at least 1.2 mm in diameter, or at least 1.3 mm in diameter, or at least 1.4 mm in diameter. In some embodiments, the vent holes are about 1.6 mm diameter.

(50) In the areas where the perforated slats 15 are joined, the extractions openings 20 can include joining pieces 16 as a component of the false bottom 5A so that the grain passes by gravity to the drop tubes 14. The drop tubes 14 are adapted to feed an extractor (e.g., an auger or conveyor) of the extraction system 3A. The passage of the grain to the extraction system 3A can be controlled by gates 22 in the joining pieces 16 that open or close depending on the status of the process to meter the grain from the tower 1 to the extraction system 3A, as shown in FIGS. 11A and 11B. FIG. 11A show the gate 22 closing grain flow between the joining piece 16 and the drop tube 14. FIG. 11B show the gate 16 open to allow grain to flow from the joining piece 16 through the drop tube 14. Operation of the gates 22 can be performed automated such that a mechanism opens and closes the gates 22. Optionally, the gates 22 can be operated manually. Alternatively, a portion of all of the gates 22 in the false bottom 5A can be operated at the same time. Alternatively, each of the gates 22 in the false bottom 5A can be operated individually.

(51) As shown in FIGS. 7 and 8, each of the extractors 17 can include multiple openings for receiving grain from multiple drop tubes 14. For example, FIGS. 7 and 8 show each extractor 17 receives grain from eight different drop tubes 14, although any suitable number is possible.

(52) In some embodiments, each extractor 17 includes at least two openings for receiving grain from a drop tube 14. In some embodiments, each extractor 17 includes at least three openings or at least four openings or at least five openings or at least 6 openings, each opening for receiving grain from a different drop tube 14.

(53) A rotary extractor 3 as shown in FIG. 5 has been used in an apparatus to extract corn and other similar grains from a grain tower. The dried grain is extracted by a rotating conical spiral auger, which under pressure from the weight of the grain, can caused deterioration of more delicate grains such as rice. To address this issue, in some embodiments, the extraction system 3A includes a series of parallel conveyors or augers 17, shown in a top view in FIG. 9, which are uniformly loaded of grain by gravity via the drop tubes 14. The conveyors 17 transport the grain from the drop tubes 14 to the outlet S4. Although, FIG. 9 shows a series of four parallel conveyors 17, any number of conveyors 17 are possible to meet the capacity needs of the grain drying apparatus.

(54) In the embodiment shown in FIGS. 7 and 8, grain can accumulate in valleys where there are no joining pieces 16 with openings 20. Embodiments shown in FIGS. 12-15 address this issue.

(55) FIG. 12 is a top view of the perforated false bottom 5A, according to another embodiment, showing the perforated slats 15 as elongated portions arranged side edge to side edge, and openings 20. FIG. 12 also shows ends of the extractors 17. FIG. 13 is a side section view of the perforated false bottom 5A taken along cut line B-B′ of FIG. 12. In the areas where the perforated slats 15 are joined, joining pieces 16 can be oriented adjacent to each other so that there are openings 20 in each valley of the perorated false bottom 5A. This embodiment includes Y drop tubes 14A that are ‘Y shaped’ where the two upper legs extend from openings 20 in adjacent joining pieces 16 and the lower leg feeds grain to the extraction system 3A.

(56) FIG. 14 is a top view of the perforated false bottom 5A, according to another embodiment, showing the perforated slats 15 as elongated portions arranged side edge to side edge, and openings 20. FIG. 14 also shows ends of the extractors 17. FIG. 15 is a side section view of the perforated false bottom 5A taken along cut line C-C′ of FIG. 14. In the areas where the perforated slats 15 are joined, one dual joining piece 16A can include two openings 20 and be oriented so that there are openings 20 in adjacent valleys of the perorated false bottom 5A. In this embodiment, grain passes through the two openings 20 of the dual joining piece 16A and into a drop tube 14 that feeds grain to the extraction system 3A.

(57) It should be understood that the foregoing description is only illustrative of the present invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the present invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications, and variances that fall within the scope of the appended claims.