FIELD OF THE INVENTION
The invention relates to length grading machines and more particularly to lifting troughs as employed by high capacity length grading machines.
BACKGROUND
Length grading machines, or grain separators, are typically used to separate a stream of grain containing various types and sizes of grain into its constituent parts, for example, wheat, durum, oats, barley and rice, and/or to separate such grains from other seed contaminants. These machines employ a rotating member, or cylinder, having lifting pockets located along an interior surface thereof, for example, formed by indentations; the pockets, according to their size, receive and lift particular lengths, or sizes of granules out of a stream of grain having been fed into the cylinder as the cylinder rotates. A trough, called a liftings trough, is mounted within the cylinder, to receive the separated granules, which are lifted by the lifting pockets; the trough may include a conveyor, for example, a screw conveyor, to transport the separated granules out from the machine.
In existing length grading machines, lifting troughs have been made larger to handle an increased amount of lifted granules in order to increase separation process efficiency. However, such an enlarged liftings trough, rather than providing the desired increased efficiency, can, by restricting the flow of granules entering the rotating cylinder, cause inlet leakage and pinching that results in a reduced efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
The following drawings are illustrative of particular embodiments of the invention and therefore do not limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description. Embodiments of the invention will hereinafter be described in conjunction with the appended drawings, wherein like numerals denote like elements.
FIG. 1A is a frontal elevation view of a prior art length grading machine, with a front cover removed to show an interior portion thereof, which includes a cut-away section.
FIG. 1B is a frontal elevation view of a length grading machine, according to exemplary embodiments of the invention, with a front cover removed to show an interior portion thereof, which includes a cut-away section.
FIG. 1C is a frontal elevation view, including a cut-away section, of a portion of the machine shown in FIG. 1B.
FIG. 2A is a top plan view of a liftings trough, according to some embodiments of the invention.
FIG. 2B is a frontal elevation view of the liftings trough of FIG. 2A.
FIG. 2C is an end view of the liftings trough of FIG. 2A.
FIG. 2D is an enlarged end view of the liftings trough mounted within a rotatable member of a length grading machine, for example as shown in FIG. 1B.
DETAILED DESCRIPTION
The following detailed description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides practical illustrations for implementing exemplary embodiments of the invention.
FIG. 1A is a frontal elevation view of a prior art length grading machine 10, and FIG. 1B is a frontal elevation view of a length grading machine 20, according to some embodiments of the invention; each of machines 10, 20 are shown with a front cover removed in order to view an interior portion thereof, which includes a partial cut-away section. FIGS. 1A and B, respectively, show both machines 10, 20 including a rotatable member or cylinder 11 extending about and along a longitudinal axis 100; cylinder 11 includes an interior surface 17, an interior space 15, surrounded by surface 17, and a plurality of lifting pockets 171 located along surface 17, for example, being formed by indentations in surface 17. With reference to FIGS. 1A-B, it should be appreciated that pockets 171 are generally uniformly distributed along interior surface 17, about axis 100 and along axis 100, over an axial length of cylinder 11, generally starting at a point 16. (For simplicity in illustration, only a portion of the plurality of pockets 171 is shown and squiggly arrows indicate the extent thereof over the axial length of cylinder 11.) FIGS. 1A-B further illustrate an inlet passageway 13, the extent of which is schematically illustrated with a bold dashed line; inlet passageway 13 opens into interior space 15 of cylinder 11 in order to deliver a flow of granular material thereto for separation, via rotation of cylinder 11.
Pockets 171 are sized to lift granules, which are in a particular size range, from the delivered stream of granules, as cylinder 11 rotates. FIG. 1A illustrates machine 10 including a liftings trough 19 mounted within cylinder 11 to receive the lifted granules therein, via an upper opening 190 thereof. It should be understood that upper opening 190 is bounded by an upper edge of two opposing end walls of trough 19, one of which is shown as an end wall 191, and by two opposing longitudinal walls of trough 19, one of which is shown as a longitudinal wall 193. Trough 19 is configured and located within cylinder 11, at a distance X from an opening through a receiving head 194 for inlet passageway 13, in order to receive a quantity of lifted granules and to accommodate a screw conveyor 14 extending therein (shown with dashed lines in FIG. 1A), which conveyor transports the lifted granules axially along trough 19 and out from machine 10. However, the illustrated location of end wall 191 of trough 19, and an intersection thereof with longitudinal wall 193 and a bottom wall 198 of trough 19, in relatively close proximity to the opening of inlet passageway 13 into interior space 15 of cylinder 11, can cause a bulk of granules flowing into cylinder 11 to become pinched between trough 19 and an inner end wall 12 of cylinder 11. This pinching can cause granules that would not otherwise be lifted by pockets 171 to be lifted, and/or cause a portion of granules to leak out from cylinder 11, at a sealed interface thereof in proximity to end wall 12, thereby significantly reducing the quantity of granules making contact with interior surface 17 of cylinder 11, and, thus, reducing an overall separation process efficiency of machine 10. FIG. 1B illustrates machine 20 including a liftings trough 29 mounted within cylinder 11, which trough 29 has an upper opening 290 that is similar in receiving capacity to opening 190 of trough 19. Yet, trough 29 has an improved configuration in order to avoid the type of pinching and leakage that is caused by the configuration of trough 19 in machine 10.
Turning now to FIGS. 2A-C, the configuration of trough 29, according to some embodiments of the invention, will be defined. FIG. 2A is a top plan view of trough 29; FIG. 2B is a frontal elevation view of trough 29; and FIG. 2C is an end view of trough 29. FIGS. 2A-C illustrate trough 29 including a first end wall 291, a second end wall 292 opposing first end wall 291, a first longitudinal wall 293 extending between first and second end walls 291, 292, a second longitudinal wall 294 opposing first longitudinal wall 293 and extending between first and second end walls 291, 292, and a bottom wall 298 extending from first end wall 291 to second end wall 292 and from first longitudinal wall 293 to second longitudinal wall 294. Each of walls 291, 292, 293 and 294 is shown including an upper edge 201, 202, 203, and 204, respectively, each of which bound upper opening 290 of trough 29.
According to the illustrated embodiment, a maximum length from upper edge 201 of first end wall 291 to upper edge 202 of second end wall 292 is greater than a maximum length of bottom wall 298 extending from first end wall 291 to second end wall 292. With reference back to FIGS. 1A-B, it may be appreciated that trough 29 is mounted within cylinder 11 such that opening 290 is located the same distance X from the opening for inlet passageway 13 as opening 190 of trough 19, yet trough 29, due to the above-described configuration, provides greater clearance for the flow of granules into cylinder via inlet passageway 13, since an intersection of bottom wall 298 with first end wall 291 is offset from the opening through the receiving head 194 at a greater distance Y. According to an exemplary embodiment of the invention, distance Y is greater than distance X by more than about 3 inches (e.g., about 3.5 inches or more). With further reference to FIG. 1B, according to certain embodiments, an axial length of upper opening 290 of the trough within cylinder 11 is at least as long as the axial length of cylinder 11 over which the plurality of lifting pockets 171 extend, while bottom wall 298 has a length that is less than the axial length of cylinder 11 over which the plurality of lifting pockets 171 extend. FIGS. 1B and 2B-C further illustrate trough 29 including a first end wall extension 299, similar to a wall extension 199 of trough 19, shown in FIG. 1A; each of troughs 19, 29 is shown mounted within interior space 15 of cylinder 11 such that the corresponding extension 199, 299 coincides with point 16 that marks an edge of the plurality of lifting pockets 171.
FIG. 2B further illustrates first end wall 291 including a slanted portion 211 extending downward and inward, toward second end wall 292, from upper edge 201, to provide the additional clearance, shown in FIG. 1B, in proximity to the opening of inlet passageway 13; another portion 212 of first end wall 291 is shown extending between slanted portion 211 and bottom wall 298 and being approximately orthogonal to a plane defined by upper opening 290. Although slanted portion 211 of wall 291 is shown, the invention is not so limited, and, for example, according to some alternate embodiments, end wall 291 includes a pair of orthogonally disposed portions, for example as illustrated by dashed lines in FIG. 2B. With reference to FIGS. 1B and C, it may be appreciated trough 29 also accommodates the screw conveyor 14, which conveyor is mounted on a shaft 27 that extends through portion 212 of first end wall 291 and is supported by a bearing assembly 28 mounted to first end wall 291.
With further reference to FIG. 2B, first longitudinal wall 293 of trough 29 includes a first longitudinal section 231 and a second longitudinal section 232. First longitudinal section 231 is shown extending from an intersection with first end wall 291 toward second longitudinal section 232, over an axial length LS1; and second longitudinal section 232 is shown extending from first longitudinal section 231 toward second end wall 292, over an axial length LS2. According to some embodiments of the invention, axial length LS1 is less than an axial length LS2, for example, LS1 may be approximately one third of an overall axial length of trough 29, while length LS2 is approximately two thirds of the overall length. In some embodiments, LS1 is less than approximately one third of an overall axial length of trough 29, while length LS2 is greater than approximately two thirds of the overall length. According to alternate embodiments, first longitudinal wall 293 may include additional longitudinal sections extending between first and second end walls 291, 292.
Turning now to FIG. 2D, which is an enlarged end view of trough 29 mounted within rotatable member 11, a contour of first longitudinal section 231 may be compared to that of second longitudinal section 232. FIG. 2D illustrates first longitudinal section 231 of first longitudinal wall 293 extending upward from bottom wall 298 at an angle θ1 which is less than an angle θ2 at which second longitudinal section 232 extends with respect to bottom wall 298. Although FIGS. 2C-D illustrate bottom wall 298 of trough 29 being multi-faceted, the invention is not so limited, and bottom wall 298 may have any suitable contour. According to the illustrated embodiment, the contour of first longitudinal section 231 provides additional clearance, in proximity to the opening of inlet passageway 13 into cylinder 11, for the flow of granular material. With further reference to FIGS. 2A-D, it should be appreciated that longitudinal sections 231, 232 are coterminous at upper edge 203 of first longitudinal wall 293, and that a contour of second longitudinal section 232 may be representative of that of an entire length of longitudinal wall 193 of trough 19 (FIG. 1B). Thus, it may be appreciated that a capacity of upper opening 290 of trough 29 to receive lifted granules may match that of upper opening 190 of trough 19, yet, the configuration of trough 29 provides for an increased clearance at the opening of inlet passageway 13 into cylinder 11. The increased clearance provided by the illustrated embodiment of trough 29, when substituted for trough 19, may increase thru put of a lifting machine by up to about 20%.
In the foregoing detailed description, the invention has been described with reference to specific embodiments. However, it may be appreciated that various modifications and changes can be made without departing from the scope of the invention as set forth in the appended claims.
Patent Grant
7891498
