Methods and Apparatus for Hulling Crops

Abstract

Improved methods and apparatus for dry hulling or dry peeling harvested crops, particularly pistachio nuts, are disclosed. The methods and apparatus of the present invention provide crop harvesting with great efficiency resulting in consistently high percentages of hulled or peeled crops and low percentages of nut breakage, without increasing processing times regardless of the sizes of the crops being hulled or peeled. The methods and apparatus of the present invention also provide for a relatively small overall machine footprint, plus easy and efficient removal and replacement of the impingement drum to accommodate for different drum speeds, different crop sizes, different bolt patterns, different bolt sizes, and other variations allowing embodiments of the invention to be used on a wide range of nuts and vegetables of different varieties, sizes and shapes.

Claims

1. An apparatus for hulling or peeling harvested crops comprising: a. a rotatable drum having a generally horizontal orientation and a central axis of rotation, said drum being positioned below at least one infeed through which incoming crops to be hulled or peeled are introduced; b. an adjustable back plate provided adjacent to said drum said back plate having a bottom that is positioned parallel to said horizontal axis of rotation; c. an adjustable front plate provided adjacent to said drum upstream from said back plate, said front plate having a bottom that is positioned parallel to said horizontal axis of rotation; and d. a plurality of protrusions located on an exterior surface of said drum, wherein each of said protrusions has a point that is directed generally toward said back plate, each point having a leading angle of between about 30 degrees and about 150 degrees, and wherein no flat side of any protrusion is oriented parallel to the horizontal axis of rotation.

2. The apparatus of claim 1 wherein the leading angles of said protrusions are between about 60 and about 120 degrees.

3. The apparatus of claim 1 wherein the leading angles of said protrusions are about 90 degrees.

4. The apparatus of claim 1 wherein the protrusions on said drum have at least one flat side having a length of not more than 10 mm.

5. The apparatus of claim 1 wherein the protrusions on said drum have at least one flat side having a length of not more than 3 mm.

6. The apparatus of claim 1 wherein the protrusions on said drum have a shape selected from the group of: triangular, square, diamond, rectangular, hexagonal, octagonal and combinations thereof.

7. The apparatus of claim 1 wherein each of said protrusions has a height of between about 3 mm and about 5 mm.

8. The apparatus of claim 1 wherein each of said protrusions has a height of about 4 mm.

9. The apparatus of claim 1 wherein the distance between tops of said protrusions and the bottom of said back plate is between about 1 mm and about 2 mm.

10. The apparatus of claim 1 wherein the distance between tops of said protrusions and the bottom of said back plate is about 1 mm.

11. A method of hulling or peeling crops comprising the steps of: a. introducing said crops into a hopper above a horizontally oriented rotating drum, said hopper comprising a drum having a plurality of protrusions located thereon, an adjustable back plate located adjacent to said drum and positioned parallel to said horizontal orientation of said drum, and a front plate located upstream from said back plate and adjacent to said drum and positioned parallel to said horizontal orientation of said drum, wherein each of said protrusions has a point that is directed generally toward said back plate, each point having a leading angle of between about 30 degrees and about 150 degrees, and wherein no flat side of any protrusion is oriented parallel to the back plate; b. said crops coming into contact with said drum protrusions and said back plate such that the crops are frictionally impinged by the protrusions on said drum causing peels or hulls to be removed from said crops and exit below said back plate; and c. said crops being moved in a counter rotational direction with respect to the rotation of said drum such that said crops come into contact with said front plate and are thereafter either urged again toward said back plate or exit below said front plate.

12. The method of claim 11 wherein each of said protrusions has a height of between about 3 mm and about 5 mm.

13. The method of claim 11 wherein each of said protrusions has a height of about 4 mm.

14. The method of claim 11 wherein the leading angles of said protrusions are between about 60 and about 120 degrees.

15. The method of claim 11 wherein the leading angles of said protrusions are about 90 degrees.

16. The method of claim 11 wherein the protrusions on said drum have a shape selected from the group of: triangular, square, diamond, rectangular, hexagonal, octagonal and combinations thereof.

17. The method of claim 11 wherein the protrusions on said drum have at least one flat side having a length of not more than 10 mm.

18. The method of claim 11 wherein the protrusions on said drum have at least one flat side having a length of not more than 3 mm.

19. The method of claim 11 wherein the rotational speed of said drum is between 100 rpm and 200 rpm.

20. The method of claim 11 wherein the rotational speed of said drum is about 100 rpm.

21. The method of claim 11 wherein the rotational speed of said drum is about 150 rpm.

22. The method of claim 11 wherein the rotational speed of said drum is reduced according to the leading angles of said majority of protrusions.

23. An apparatus for hulling or peeling harvested crops comprising: a. a rotatable drum having a generally horizontal orientation and a central axis of rotation, said drum being positioned below at least one infeed through which incoming crops to be hulled or peeled are introduced; b. an adjustable back plate provided adjacent to said drum said back plate having a bottom that is positioned parallel to said horizontal axis of rotation; c. an adjustable front plate provided adjacent to said drum upstream from said back plate said front plate having a bottom that is positioned parallel to said horizontal axis of rotation; and d. a plurality of protrusions located on an exterior surface of said drum, wherein a majority of said protrusions has a point that is directed generally toward said back plate, each point having a leading angle of between about 30 degrees and about 150 degrees, and wherein a minority of said protrusions has a flat side that is oriented parallel to the horizontal axis of rotation.

24. The apparatus of claim 23 wherein the leading angles of said majority of protrusions are between about 60 and about 120 degrees.

25. The apparatus of claim 23 wherein the leading angles of said majority of protrusions are about 90 degrees.

26. The apparatus of claim 23 wherein the protrusions on said drum have at least one flat side having a length of not more than 10 mm.

27. The apparatus of claim 23 wherein the protrusions on said drum have at least one flat side having a length of not more than 3 mm.

28. The apparatus of claim 23 wherein the protrusions on said drum have a shape selected from the group of: triangular, square, diamond, rectangular, hexagonal, octagonal and combinations thereof.

29. The apparatus of claim 23 wherein each of said protrusions has a height of between about 3 mm and about 5 mm.

30. The apparatus of claim 23 wherein each of said protrusions has a height of about 4 mm.

31. The apparatus of claim 23 wherein the distance between tops of said protrusions and the bottom of said back plate is between about 1 mm and about 2 mm.

32. The apparatus of claim 23 wherein the distance between tops of said protrusions and the bottom of said back plate is about 1 mm.

33. A method of hulling or peeling crops comprising the steps of: a. introducing said crops into a hopper above a horizontally oriented rotating drum, said hopper comprising a drum having a plurality of protrusions located thereon, an adjustable back plate located adjacent to said drum and positioned parallel to said horizontal orientation of said drum, and a front plate located upstream from said back plate and adjacent to said drum and positioned parallel to said horizontal orientation of said drum, wherein a majority of said protrusions has a point that is directed generally toward said back plate, each point having a leading angle of between about 30 degrees and about 150 degrees, and wherein a minority of said protrusions has a flat side that is oriented parallel to the horizontal axis of rotation; b. said crops coming into contact with said drum protrusions and said back plate such that the crops are frictionally impinged by the protrusions on said drum causing peels or hulls to be removed from said crops and exit below said back plate; and c. said crops being moved in a counter rotational direction with respect to the rotation of said drum such that said crops come into contact with said front plate and are thereafter either urged again toward said back plate or exit below said front plate.

34. The method of claim 33 wherein each of said protrusions has a height of between about 3 mm and about 5 mm.

35. The method of claim 33 wherein each of said protrusions has a height of about 4 mm.

36. The method of claim 33 wherein the leading angles of the majority of said protrusions are between about 60 and about 120 degrees.

37. The method of claim 33 wherein the leading angles of the majority of said protrusions are about 90 degrees.

38. The method of claim 33 wherein the protrusions on said drum have a shape selected from the group of: triangular, square, diamond, rectangular, hexagonal, octagonal and combinations thereof.

39. The method of claim 33 wherein the protrusions on said drum have at least one flat side having a length of not more than 10 mm.

40. The method of claim 33 wherein the protrusions on said drum have at least one flat side having a length of not more than 3 mm.

41. The method of claim 33 wherein the rotational speed of said drum is between 100 rpm and 200 rpm.

42. The method of claim 33 wherein the rotational speed of said drum is about 100 rpm.

43. The method of claim 33 wherein the rotational speed of said drum is about 150 rpm.

44. The method of claim 33 wherein the rotational speed of said drum is reduced according to the leading angles of said majority of protrusions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] FIG. 1 is a partial side schematic view of a prior art hulling apparatus.

[0070] FIG. 2 is a top schematic view of counter rotational patterns of prior art hulling apparatus.

[0071] FIG. 2A is a side schematic view of a counter rotational pattern of prior art hulling apparatus.

[0072] FIG. 3 is a top schematic view of a counter rotational pattern of embodiments of the present invention.

[0073] FIG. 3A is a side schematic view of a counter rotational pattern of embodiments of the present invention.

[0074] FIG. 4 is a schematic view showing exemplary angles , and T with respect to the front plate and back plate of an embodiment of the invention.

[0075] FIG. 5 is a schematic view showing exemplary angles , and T with respect to the front plate and back plate of an embodiment of the invention.

[0076] FIG. 6 is a side perspective view of an embodiment of a front plate in an embodiment of the present invention.

[0077] FIG. 7 is a perspective view of an embodiment of the invention illustrating exemplary drum removal.

[0078] FIGS. 8A-8C are views of different embodiments of the front plate showing different positions for the opening and gates thereon.

[0079] FIGS. 9A-9C are side schematic views of different examples of possible positions and angles of front and back plates of embodiments of the present invention.

[0080] FIG. 10 is a view of an exemplary pattern of protrusions provided on the surface of a drum according to an embodiment of the invention.

[0081] FIG. 11 is a perspective view of an embodiment of a drum of the present invention having triangular bolts or protrusions thereon.

[0082] FIG. 12 is a perspective view of an embodiment of a drum of the present invention having diamond shaped bolts or protrusions thereon.

[0083] FIG. 13 is a perspective view of an embodiment of a drum of the present invention having hexagonal bolts or protrusions thereon.

[0084] FIG. 14 is a perspective view of an embodiment of a drum of the present invention having octagonal bolts or protrusions thereon.

[0085] FIG. 15 is a side view of an embodiment of a drum of the present invention having triangular bolts or protrusions thereon.

[0086] FIG. 16 is a side view of an embodiment of a drum of the present invention having diamond shaped bolts or protrusions thereon.

[0087] FIG. 17 is a side view of an embodiment of a drum of the present invention having hexagonal bolts or protrusions thereon.

[0088] FIG. 18 is a side view of an embodiment of a drum of the present invention having octagonal bolts or protrusions thereon.

[0089] FIG. 19A is a diagrammatic view of an embodiment of a triangular bolt or protrusion of a drum of the present invention.

[0090] FIG. 19B is a diagrammatic view of an embodiment of a square bolt or protrusion of a drum of the present invention.

[0091] FIG. 19C is a diagrammatic view of an embodiment of a rectangular bolt or protrusion of a drum of the present invention.

[0092] FIG. 19D is a diagrammatic view of an embodiment of a diamond shaped bolt or protrusion of a drum of the present invention.

[0093] FIG. 19E is a diagrammatic view of an embodiment of a hexagonal bolt or protrusion of a drum of the present invention.

[0094] FIG. 19F is a diagrammatic view of an embodiment of an octagonal bolt or protrusion of a drum of the present invention.

DETAILED DESCRIPTION

[0095] Referring to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, and referring particularly to FIGS. 3A, 4 and 5, it is seen that the embodiments of the invention shown in these illustrations include a rotatable drum 11 having a central axis 12, the drum being located at the bottom of a hopper area 10 of a hulling apparatus for receiving harvested crops 17 such as nuts or vegetables from which the outside hulls, skins or peels 18 are to be removed, resulting in processed crops 19 that have been hulled, peeled and/or skinned. The drums of embodiments of the present invention are provided with upwardly extending protrusions, impingement structures or bolts 14 on the surface of the drum. The protrusions 14 are ordinarily provided in a pattern 15. The protrusions 14 are designed to impinge against the incoming crops 17 that come into contact with the drum for the purpose of frictionally removing the exterior skins, peels or hulls 18 from the crops.

[0096] Embodiments of the present invention are provided with an adjustable back plate 6 and an adjustable front plate 7 mounted in the vicinity of the drum 11. The area between the front and back plates generally defines a hopper 10 of the apparatus. In the embodiments illustrated herein, the rotational direction of the drum is shown to be clockwise; however it is to be appreciated that the drums of embodiments of the present invention may alternatively rotate in a counter-clockwise direction, and if so, the positioning of the other elements of the embodiments of the invention would be provided in mirror-image positions relative to such counter-clockwise rotating drums.

[0097] Placing the crops 17 into the hopper area 10 of embodiments of the invention causes the crops to come into contact with the protrusions 14 of the drum; and the rotation of the drum 11 causes the crops to come into contact with back plate 6. The position of the back plate 6 in conjunction with the protrusions on the drum cause frictional impingements (hits or contacts) which contribute to the removal of the exterior skins, peels or hulls 18 from the crops without increasing breakage, and with little or no increase in processing times.

[0098] In embodiments of the invention, using particular locations and angles for the front and back plates causes increased impingement of the crops and results in more efficient removal of the exterior hulls 18. Embodiments of the invention include methods and apparatus wherein the bottom or starting position of the adjustable back plate 6 relative to the drum 11 is located at a position directly above the drum at or near top dead center (12:00 on a clock face), with the edge of the back plate being above the surface of the drum, and parallel to the axis 12 of the drum. In some embodiments, the bottom of the back plate may be located as much as about 3 degrees down from top dead center in the upstream direction of drum rotation, and in same quadrant as the front plate. (See, e.g., FIG. 9A.) For a drum rotating in a clockwise direction, the bottom of an exemplary back plate located 3 degrees down from top dead center would be located at around 11:59:30 on a clock face. In all embodiments, the adjustable front plate 7 is located in the upstream quadrant below top dead center (e.g., between 9:00 and 12:00 on a clock face if the drum is rotating clockwise).

In embodiments of the invention, the top of the back plate 6 may be angled or tilted from the bottom of the back plate (pivoted) in a direction away from the front plate 7 at an angle 31 of between about zero (0=vertical) and about 15 degrees. It has been observed that some crops tend to accumulate on the back plate 6 if it is tilted at an angle of 20 degrees or more, resulting in a preferred range for angle 31 of between about 0 and about 15 degrees. Referring to the exemplary embodiment illustrated in FIG. 5, it is seen that the bottom of back plate 6 in this example is located at top dead center (12:00), and that back plate 6 is tilted in an angle 31 of about 10 degrees away from the front plate 7.

[0099] In embodiments of the invention, the distance between the bottom of back plate 6 and the surface of drum 11 may be adjustable such that a gap 8 may be formed between the back plate 6 and the drum 11. It is to be appreciated that peels and removed hull fragments 18 that are dislodged during the impingement process exit through this gap 8. For embodiments hulling pistachio nuts, this gap may be from between about 3 mm and about 5 mm high. Although gap 8 is not necessarily dependent on the height of the protrusions 14 on the drum, in some embodiments it may be approximately 1 mm above the tops of these protrusions. This allows the hulls 18 to exit, but not the nuts themselves 19. In other embodiments, the size of gap 8 may be from between about 2 mm and about 5 mm so as to allow for peels and removed hull fragments 18 to exit, while preventing hulled crops 19 from also exiting through gap 8. In some embodiments, gap 8 may be larger in order to accommodate larger sized products, such as walnuts.

[0100] Embodiments of the invention include methods and apparatus wherein the bottom or starting position of the adjustable front plate 7 relative to the drum 11 is located at a position upstream from the back plate 6 with respect to the rotation of the drum. In preferred embodiments for hulling pistachios, this starting position of the bottom of the front plate 7 is around 37 degrees below top dead center, or just below 11:00 on a clock face if the drum is rotating clockwise. However, depending on the application of the formula described below, the starting position of the bottom of the front plate 7 may be anywhere from about 25 to about 50 degrees down from top dead center, but preferably between about 27 degrees and 42 degrees down from top dead center.

[0101] In embodiments of the invention, the top of the front plate 7 may be angled or tilted from the bottom of the front plate (pivoted) in a direction away from the back plate 6 at an angle 37 (T) of between about zero (0=vertical) and about 15 degrees. It has been observed that crops tend to accumulate on the front plate 7 if it is tilted at an angle of 20 degrees or more, resulting in a preferred range for angle T of between about 0 and about 15 degrees. Referring to the exemplary embodiment illustrated in FIG. 5, it is seen that the bottom of front plate 7 is located at 37 degrees down from top dead center in an upstream direction, and that front plate 7 is tilted in an angle T of about 10 degrees from vertical with the top leaning away from the back plate 6.

[0102] In embodiments of the present invention, it has been determined that three different angles are important to improved throughput and reducing breakage in nuts such as pistachios. (See FIGS. 4 & 5.) The first angle 35 (alpha or ) is the location of the bottom of the front plate 7 relative to the bottom of the back plate 6 taken from the center of the drum 12 in a cross section view. By way of example, and without limitation, for an embodiment with a 20 drum having a radius of 10 (ten inches) where r=10, and a back plate 6 having its bottom located at top dead center, it has been determined that for hulling pistachios a preferred angle alpha () should be approximately 37.

[0103] The next important angle 36 (beta or ) is the angle of the front plate 7 itself toward the back plate 6, based on the position of the bottom of the front plate along the drum. It has been determined that this angle should almost always be approximately 27 in a direction toward the back plate when hulling pistachios. The final angle 37 (tilt or T) is the angle between the front plate 7 and a vertical line at that point of the drum. The relationship between the three angles is described in the following formula: Alphabeta=T (=T). However, T should not be greater than 20 because any larger tilt would result in piling up (dead zones) of nuts against the front plate 7, and any T of less than zero could result in nut breakage.

[0104] Referring to the exemplary embodiment of FIG. 5, the bottom of the front plate 7 is located 37 down from top dead center (=37), so it's starting position would extend out radially at 37. This is a preferred starting location for hulling pistachios. Front plate 7 is then be slanted 27 toward the back plate (=27), which results in the front plate having a tilt of 10 (T=10) away from vertical. Since beta is almost always 27 degrees when hulling pistachios, and T should not be greater than 20 and less than zero, then 27=T or =T+27. Based on this formula the possible range for a would be 27 (when T=0) to 47 degrees (when T=20). So by way of example, if a is selected to be 40 degrees, then angle T would be 13 degrees (4027=13). (See FIG. 9C.). When embodiments of the invention are used to hull nuts, particularly pistachios, it is to be appreciated that a front plate located 42 or more down from top dead center or located 27 or less from top dead center could lead to increased nut breakage and/or dead zones on the plates. However, these limitations do not necessarily apply to vegetables (carrots, potatoes, etc.) or nuts other than pistachios.

[0105] Referring to the exemplary embodiment of FIG. 9B, the bottom of the front plate 7 is located 27 degrees down from top dead center, so angle 35 () is 27 degrees, and the starting position for front plate 7 would extend out radially at 27 degrees. In FIG. 9B, front plate 7 has been slanted 27 degrees toward the back plate 6, so angle 36 () is also 27 degrees. This results in bringing the front plate 7 to vertical (T=0).

[0106] Referring to the exemplary embodiment of FIG. 9C, the bottom of the front plate 7 is located 40 degrees down from top dead center, so angle 35 () is 40 degrees, and the starting position for front plate 7 would extend out radially at 40 degrees. In FIG. 9C, front plate 7 has been slanted 27 degrees toward the back plate 6, so angle 36 () is 27 degrees. This gives the front plate 7 a tilt of 13 degrees away from vertical (T=13).

[0107] Embodiments of the invention include methods and apparatus wherein a central opening 21 is provided in the front plate 7 through which processed crops 19 may exit. In these embodiments, crops are introduced through one or more infeeds located at or near opposite ends 9a, 9b of the drum 11 and are urged toward the center of the drum using various patterns 15 including, without limitation, chevron and herring bone patterns. These patterns alone or in conjunction with the positioning of the front plate 7 and back plate 6, cause the crops to move in tight counter-rotational patterns 28 as shown in FIGS. 3 and 3A. Depending on the height and position of opening 21, it is possible for the crops in these patterns 28 to encounter a high or a low number of impingements before reaching the central opening 21 where they exit in a processed condition 19.

[0108] In these embodiments, opening 21 is located near the center of the front plate 7 above the drum 11. In most embodiments, the length and width of opening 21 may be varied using one or more adjustable gates. The size of the opening 21 may be adjusted in advance, or in real time during processing. In these embodiments, adjustment of the height of the opening 21 may be accomplished using one or two adjustable gates. In many embodiments, a first adjustable gate 22 (upper gate) is provided above opening 21 which may be raised to increase the size of the opening, or lowered to decrease the size of the opening. In most embodiments, a second gate 23 may also be provided below the opening (lower gate) which prevents crops at or near the drum surface from exiting through opening 21. It is to be appreciated that by coordinating the positions of these two gates, the opening 21 between them may be raised or lowered relative to the drum.

[0109] It is to be appreciated that by increasing the heights of the first 22 and second 23 gates, the opening 21 may be moved higher such that crops near the top of the counter rotation 28 may exit, while crops at or near the drum surface are likely to receive additional impingements which may be desirable for more thorough processing (hulling/peeling) of these crops as they work their way toward the top of the counter rotation. Similarly, by lowering the heights of the first and second gates, the opening 21 is moved lower such that crops in lower levels of the counter rotation 28 are allowed to exit the machine, which may be desirable if the crops require fewer impingements for peeling.

[0110] In some embodiments, a single adjustable lower gate 23 may be provided below a large opening 21 which may be raised to cause additional nut impingements to accomplish additional processing, or lowered to reduce impingements if additional processing is not needed.

[0111] In some embodiments no lower gate may be provided, and a single adjustable upper gate 23 may be provided which may be raised to increase the size of opening 21 resulting in fewer impingements before the crops are able to exit, or lowered to reduce the size of the opening and increase impingements if additional processing is needed.

[0112] By way of example and without limitation, an opening 21 may be as large as 6 by 6 when fully opened, and embodiments of the lower gate 22 may have height of up to 3, leaving an opening of up to 3 above lower gate 22, depending on whether the upper gate 23 is also being used. It is to be appreciated that the size and location of the opening 21 may be adjusted depending on how full the machine is running, and that the upper and lower gates 22, 23 may be used to adjust the opening 21 upward in order to only allow crops near the top of the pile to exit. In some embodiments, adjustable left and right side gates 25, 26 may also be provided to widen or narrow the width of opening 21, or move the lateral position of opening 21 left or right.

[0113] It is to be appreciated that in alternative embodiments, two similarly adjustable openings may be provided on either side of front plate 7, the crops may be introduced above the center of drum 11, and the patterns 15 of protrusions on the drum urge the crops away from the center and toward the two side openings.

[0114] By way of example and without limitation, if the incoming product from the field is substantially hulled before reaching the center opening on the drum, there may be no need to have the bottom gate at all, since no additional impingements are necessary. In such cases a 3 by 6 opening 21 can be placed at the very bottom of the front plate above the drum without any lower gate, as shown in the exemplary embodiment of FIG. 8A.

[0115] By way of example and without limitation, if the operator decides to employ aggressive peeling because the hulls are more hardened, the front plate opening 21 may be positioned at a very high location (e.g., the lower plate 23 may be up to about 3 tall), so that the crops undergo considerable impingements before exiting, as shown in the exemplary embodiment of FIG. 8C.

[0116] However, in another example and without limitation, if the majority of incoming nut products are ripe, but there still is a small unripe subpopulation, the operator may choose a less aggressive peeling and faster process time for the product, and may set the height of the lower gate 23 to be only around 1 or perhaps around 2 tall as shown in the exemplary embodiment of FIG. 8B.

[0117] Referring to the embodiment of FIG. 7, it is seen that drum 11 may be inserted or removed in a lateral direction along slots 13a and 13b of the machine, without disassembly of the machine nor removal of either back plate 6 or front plate 7. This is possible because in embodiments of the invention, both back plate 6 and front plate 7 may be located in the same quadrant, which is on the opposite side of the machine from drum removal slots 13.

[0118] It is to be understood that variations and modifications of the present invention may be made without departing from the scope thereof. It is also to be understood that the present invention is not to be limited by the specific embodiments disclosed herein, but only in accordance with the appended claims when read in light of the foregoing specification.