Machine for hulling nuts

A machine for hulling nuts having a rotationally driven horizontal disc provided with an upwardly disposed abrasive surface; a cylindrical casing coaxially related to the disc, closely spaced from its periphery, and provided with a discharge opening; a cover closing the casing above the disc and provided with a supply opening adjacent to the discharge opening; and a plurality of blades spaced around the disc and extending generally radially across it to guide nuts deposited in an unhulled condition on the disc through the supply opening in a path around the disc and alternately centrally and peripherally of the disc toward the discharge opening, the hulls being abraded from the kernals as the nuts traverse the path and being urged centrifugally from the disc to fall between it and the casing while the separated kernels exit through the discharge opening.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a machine for hulling nuts, and more 
particularly to such a machine which, in a continuous operation, hulls 
pistachio nuts and the like by abrasion and separates the hulls from the 
remainder of the nuts. 
2. Description of the Prior Art 
Machines for removing a hard, inedible outer layer from vegetable food 
sources, such as nuts, are well known. However, all of these machines 
known to the applicant have one or more deficiencies. Typically, such 
deficiencies include relatively slow processing and damage to the kernel 
by crushing or friction inherent in the type of operation used in removing 
the hulls. Many such machines do not separate the removed hulls from the 
inner shells or the kernals or do so imperfectly. Certain hulling machines 
are not adjustable so as to handle variations in the nuts to be hulled, 
such as moisture content due to differences in growing or storing 
conditions, while other machines require excessive manual attention 
throughout the hulling operation. Pistachio nuts present serious hulling 
problems in connection with which the present invention is conveniently 
illustrated. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved machine for 
hulling pistachio nuts and the like. 
Another object is to provide such a machine which can be adjusted to 
accommodate various characteristics for complete hulling of nuts without 
injury to the kernels. 
Another object is to provide such a machine which, once adjusted, rapidly 
and continuously removes the hulls without further attention. 
Another object is to provide such a machine which separates the detached 
hulls from the nuts in a continuous operation. 
Another object is to provide a machine for hulling nuts which removes the 
hulls by abrasion against a rotating disc while the nuts are guided in a 
path alternately toward and from the center of the disc with the detached 
hulls being separated from the nuts by centrifugal force exerted along the 
path. 
Another object is to provide such a machine which utilizes guide blades 
which can be conveniently adjusted to vary the time of travel of the nuts 
through the machine and control their tumbling velocity. 
Another object is to provide such a machine wherein the abrasion process 
can be selectively lubricated by the addition of water or other fluid. 
PRIOR ART STATEMENT 
Characterizing the closest prior art of which the applicant is aware and in 
compliance with 37 C.F.R. 1.97 and 1.98, attention is invited to the 
following patents, copies of which are enclosed. 
Vaughan, U.S. Pat. No. 1,574,138, Feb. 23, 1926 
Heller, U.S. Pat. No. 1,766,513, June 24, 1930 
Zeun, U.S. Pat. No. 2,428,903, Oct. 14, 1947 
The Vaughan Patent is believed relevant in its disclosure of a nut hulling 
machine utilizing a rotating abrasive disc. The machine utilizes vanes to 
sweep the hulls and detached kernels from the disc. However, the vanes are 
not adjustable and the hulls and kernels make a single pass over the disc 
from its center to its periphery where they are discharged in intermixed 
condition. 
The Heller U.S. Pat. No. 1,766,513 discloses a somewhat similar machine for 
decorticating grains in which weight of the grains holds them against a 
"grinding disc or stone" while the grains travel outwardly in radial 
channels. Wipers are used to sweep the removed shells into "air channels" 
alternating with the radial channels where the shells, apparently, are 
removed by a flow of air. 
The Zeun U.S. Pat. No. 2,428,903 is believed relevent in its disclosure of 
a machine for the removal of skin from coconut meat by an abrasive disc 
supplied with water. The detached skin is centrifugally separated and 
discharged periperally of the disc. However, the nut meat is previously 
husked and shelled and is held against the disc manually during the 
abrading operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring more particularly to the drawings, the figures show a machine 10 
for hulling nuts embodying the principles of the present invention. The 
machine, typically, is supported on a floor 12 and includes a base 
indicated generally by the numeral 20 and unitarily constructed, as by 
welding. The base includes a central box 25 of square horizontal cross 
section which extends upwardly from the floor. The box has vertical sides 
26 and is open at its upper and lower ends. A pair 28 of horizontal bars 
extend in parallel spaced relation centrally across each end of the box. 
Each pair of bars supports a sleeve bearing 30. The bearings are aligned 
about a substantially vertical axis 31 disposed centrally of the box. The 
upper of the bearings is provided with an annular, upwardly facing thrust 
surface 33. 
The base 20 includes a cylinder 40 which circumscribes the box 25 and is 
aligned with the vertical axis 31. The cylinder has an open upper axial 
end 41 which is substantially coplanar with the upper end of the box and 
has an open lower end 42 which is spaced upwardly of the floor 12. The 
cylinder is fixedly mounted on the box by eight square horizontal tubes 45 
extending radially inwardly from the cylinder to the box. The tubes are 
disposed in pairs individually related to each side 26 of the box, each 
pair being disposed in vertically spaced relation centrally of the 
corresponding side of the box. The upper end of the cylinder is 
circumscribed by a horizontal annular flange 47. 
The apparatus 10 has an annular trough 50 mounted on the floor 25 
concentrically with the cylinder 40. The trough has an outer wall 52 
having a diameter equal to that of the cylinder and extending from the 
floor toward the lower end 42 of the cylinder. The trough has a 
fragmentarily represented channel 55 extended radially from it. 
The apparatus 10 has a disc assembly 60 of unitary construction which is 
received in the bearings 30 for rotation about the upright axis 31. The 
assembly has a central cylindrical journal 62 which is rotationally fitted 
in the bearings and extends from a lower axial end adjacent to the floor 
12 to an upper axial end spaced upwardly of the thrust surface 33. A 
horizontal disc 65 is mounted on the upper end of the journal with the 
center of the disc substantially aligned with the axis. The periphery of 
the disc has a diameter somewhat less than the interior diameter of the 
cylinder 40. The disc has a planar upper abrading surface 66 which is 
ground so as to be substantially flat and disposed substantially normal to 
the axis. The surface includes a peripheral portion 67 and a central 
portion 68. A layer of abrasive grit 71 is applied adhesively to the upper 
surface. The layer substantially covers the surface and is of uniform 
depth. Preferably, the layer is of silicon carbide, 16 grit particles and 
is approximately 0.1875 inch (approximately 4.75 mm) in thickness. 
The disc assembly 60 has a plurality of gusset plates 75 extending radially 
from the journal 62 toward the periphery of the disc 65 at its side 
opposite the surface 66. These plates are angularly spaced about the 
journal, and the ends of the plates adjacent to the journal extend 
downwardly therefrom approximately one-half of the distance from the disc 
to the thrust surface 33. The assembly has a cylindrical collar 77 
concentrically related to the journal and extended between the gusset 
plates and the thrust surface. The collar is slidably fitted to the 
journal so that the weight of the disc assembly is rested on the collar 
and transferred through it to the thrust surface. 
The machine 10 includes a power rotational drive assembly, indicated 
generally by the numeral 80, which drives the disc assembly in a direction 
of rotation indicated by the arrows 81. The assembly is preferably of a 
type adapted selectively to drive the disc at a variable speed. It has 
been found that with a disc approximately 48 inches (approximately 23 cm) 
in diameter, a speed range of 100 to 500 r.p.m. provides for the hulling 
of pistachio nuts of a variety of characteristics at a rate of 
approximately 3,500 lbs. (1360 kg) per hour. The drive assembly includes a 
driven sprocket 83 concentrically fixed on the journal 62 between the 
bearings 30 and a speed reducer 85 of well-known construction mounted on a 
bracket extending downwardly from one of the bars of the upper pairs 28 
thereof. The reducer has an output shaft which is parallel to the journal 
and is fitted with a sprocket 87 aligned with the driven sprocket. An 
input shaft is extended through one of the square tubes 45 to the reducer. 
An endless chain 91 links the sprockets 83 and 87 to drive the disc 
assembly from the reducer. The drive assembly is provided with an electric 
motor 93 mounted externally of the cylinder 40 on a bracket 94 and 
connected in rotational driving relation to the input shaft oppositely of 
the reducer. 
The machine 10 has a cylindrical casing 100 mounted on the upper end 41 of 
the cylinder 40 and coaxially related to the disc 65. The casing 
circumscribes the disc and extends upwardly from the cylinder to an upper 
axial end 101 spaced substantially above the disc. The disc is thus 
disposed for rotation concentrically within the casing. The lower axial 
end of the casing is open and is circumscribed by a flange 103 mating 
axially with the flange 47. These flanges are provided with a plurality of 
angularly spaced, aligned bores, not shown, individually fitted with bolt 
assemblies 104 which detachably secure the casing to the cylinder. The 
radius of the periphery of the disc is less than the radius of the 
interior of the casing so that there is a gap 105 between the periphery of 
the disc and the casing. The gap preferably has a width substantially less 
than the smallest diameter of a shell or kernel of a nut to be hulled by 
the machine. For hulling pistachio nuts, the width of this gap is, 
typically, 0.25 inch (6.35 mm). 
The casing 100 is provided with a circumferentially extending discharge 
opening 110. The opening extends in a direction parallel to the axis 31 
from the upper end 101 of the casing to a point approximately at the level 
of the underside of the disc 65. The opening has a first side 112 and an 
opposite second side 113 spaced angularly from each other about the axis. 
The first side is spaced from the second side in the direction of rotation 
indicated by the arrows 81. These sides lie in individual planes which 
include the axis and extend radially therefrom. The included angle between 
these planes is relatively small. Typically, the diameter of the casing is 
approximately 48 inches (approximately 123 cm) and the width of the 
opening is approximately 6 inches (approximately 15 cm). A spout 115 is 
mounted on the casing and is extended downwardly and radially outwardly 
from the opening. 
The machine 10 has a discoidal cover 120 which is mounted on and closes the 
upper end 101 of the casing 100. The cover is substantially normal to the 
axis 31 and is, therefore, substantially parallel to the upper surface 66 
of the disc 65. The cover, typically, is spaced upwardly from the disc a 
distance of approximately 2 inches (5 cm). The cover is provided with a 
peripherally disposed supply opening 125 adjacent to the discharge opening 
110. In a machine having the typical dimensions previously described, the 
supply opening extends inwardly from the periphery of the casing a 
distance of approximately 6 inches (15 cm). The opening is trapezoidal in 
shape, having a first edge 126 lying in a plane which includes the axis 31 
and extends radially therefrom in an intersecting relation to the 
discharge opening. This plane is spaced approximately two-thirds of the 
distance in the direction 81 of rotation from the first side 112 of the 
discharge opening toward its second side 113. The supply opening has a 
second edge 127 opposite the first edge and spaced therefrom in the 
direction of rotation approximately one-half of the distance between the 
edges of the discharge opening. As a result, the first and second edges of 
the supply opening, respectively, are spaced in the direction of rotation 
from the first and second sides of the discharge opening. The discharge 
opening thus extends oppositely of the direction of rotation from the 
plane of its first edge. The end of the second edge toward the center of 
the cover is spaced somewhat in the direction of rotation from the 
peripherally disposed end of the second edge so that the second edge is 
angularly related to the first edge. 
The cover 120 has a central, liquid admitting fitting 130 for admitting 
water onto the central portion 68 of the surface 66 of the disc 65. The 
fitting is connected by a conduit 131 to a source of water, not shown, 
capable of providing a flow in the order of 50 gallons (190 liters) per 
minute. The conduit is provided with a valve 132 for regulating the flow 
of water. 
The machine 10 includes six substantially identical first or inward path 
guide blades, or alternate but directing vanes 140. The machine includes 
six second intermediate blades or nut directing vanes 141 and 142. The 
second blades include five substantially identical outward path guide 
blades 141 and a single discharge blade 142. All of the blades are 
elongated and disposed between the cover 120 and the upper surface 66 of 
the disc and are stationary when the machine is in operation. Each blade 
has a linear lower edge 145 disposed in parallel and upwardly spaced 
adjacent relation to the upper surface 66 of the disc 65 and to the 
abrasive layer of grit 71. Each lower edge is preferably spaced 
substantially equally from the disc a distance in the range of 0.0625 to 
0.1875 inch (1.6 to 4.8 mm). Each lower edge thus defines a debris passage 
146 between it and the grit-covered upper surface. Each blade has an 
entrance end section terminating in an entrance end 147. Each of the 
inward and outward path guide blades has an exit section which is opposite 
the entrance section or passage and terminates in an exit end 148. The 
discharge blade has a corresponding exit section which is relatively 
elongated and terminates in a discharge end 149. The first and second 
blades extend generally radially of the axis 31. The entrance end of each 
first blade is disposed toward the casing 100 so that, in relation to the 
casing, the entrance end is the outer end of the blade and the exit end is 
the inner end of the blade. Each second blade is disposed with its 
entrance end toward the axis so that this end is the inner end of the 
blade and the exit end is the outer end. The length of the blades is such 
that the first blades extend across the peripheral portion 67 of the 
surface 66 toward and substantially over its central portion 68 while the 
second blades extend across the central portion toward and substantially 
over the peripheral section. 
Each blade 140, 141, and 142 is mounted on the casing 100 for limited 
adjustable pivotal movement about individual axes 150 which are parallel 
to the axis 31. Each of these axes is disposed substantially at the 
entrance end 147 of the corresponding blade. Due to this pivotal movement, 
the angle of each blade relative to a radius extended therethrough from 
the axis 31 is adjustable through an acute angle relative to the radius. 
When the blades are disposed at the midpoints of their respective pivotal 
movement, the second blades 141 and 142 extend substantially along a 
radius from the axis while the first blades 140 are angularly related to 
such a radius. When each first blade is disposed at the midpoint of its 
movement, its exit end 148 is spaced somewhat in the direction 81 of 
rotation from such a radius extended through the entrance end of the first 
blade. As a result, each first blade extends forwardly in the direction of 
rotation. 
The blades 140, 141, and 142 each have a bolt fixedly mounted thereon 
toward the exit end 148 thereof. The bolt has a screw-threaded shank 155 
which extends upwardly from the blade through a corresponding arcuate slot 
157 in the cover 120. This slot is concentric with the axis 150 of the 
corresponding blade. Each shank is screw-threadably engaged upwardly by a 
nut 159 which, when tightened, clamps the corresponding blade to the cover 
to maintain the blade at a selected point of adjustment along the pivotal 
movement about its axis 150. 
The second blades 141 and 142, as previously described, extend generally 
along individual radii from the axis 31. These radii are substantially 
equally angularly spaced about the axis with the radius corresponding to 
the discharge blade 142 lying substantially in a plane extended radially 
from the axis and including the first edge 126 of the supply opening 125. 
The first blades 140 are equally angularly spaced about the axis and are 
disposed individually between the second blades. The first and second 
blades thus alternate about the axis. An outward path guide blade 141 is, 
therefore, disposed between each adjacent pair of the first or inward path 
guide blades 140, except for the pair of inward guide blades adjacent to 
and opposite of the plane wherein the discharge blade extends. The one of 
the inward path blades adjacent to this blade and disposed in the 
direction 81 of revolution from it is substantially aligned with the edge 
127 of the supply opening. The relative disposition of this one of the 
first blades and the discharge blade is substantially identical to the 
relative disposition of each of the other inward path guide blades to the 
adjacent outward path guide blades disposed therefrom in a direction 
opposite the direction 81 of revolution. 
Referring in greater detail to the blades 140, 141, and 142, the entrance 
end 147 of each of the first or inward path guide blades 140 is closely 
adjacent to the inner surface of the casing 100 as is the correspondingly 
pivotal axis 150. Each of these entrance ends is interconnected with the 
casing by a hinge 170 disposed to provide the previously described pivotal 
movement about this axis. The length of each inward guide blade is 
approximately two-thirds of the radius of the disc 65 so that the exit end 
148 of the blade is spaced radially from the axis 31, providing a 
corresponding first nut passage 172 past the blade and disposed between it 
and the axis. 
The outward path guide blades 141 are substantially equal in length to the 
blades 140 so that the exit ends 148 of the outward guide blades are 
spaced substantially from the casing 100 and the periphery of the disc 65. 
A second nut passage 173 is thus provided past each of these blades 
between its exit end and the casing. The entrance ends 147 and the 
corresponding axes 150 of these blades are adjacent to the axis 31. Each 
of these entrance ends is provided with a screw-threaded stud 175 aligned 
with the axis and extended individually upwardly through a corresponding 
aligned bore 176 in the cover 120. Each stud is pivotally fitted in the 
corresponding bore, and, outwardly of the cover, is screw-threadably 
engaged by a nut 177. Each outward path guide blade is provided with a 
shield plate 181 mounted upwardly on its exit section toward its exit end 
148. This plate extends from the exit section oppositely of the direction 
of rotation and parallel to the inner surface of the cover beneath the 
corresponding slot 157. The corresponding shank 155 is mounted on this 
plate so as to extend upwardly therefrom through this slot. 
The discharge blade 142 is similar to each of the blades 141 in the 
disposition of its entrance end 147 relative to the axis 31 and in having 
a substantially identical stud 175 which extends through a bore 176 in the 
cover 120 and is engaged by a nut 177. The discharge blade has a shield 
plate 185 from which the corresponding shank 155 extends. This shank, the 
portion of the shield plate adjacent to it, and the portion of the 
discharge blade extending from this shank to the entrance end of the 
discharge blade are substantially identical to the corresponding portion 
of the blades 141. However, the exit section of the discharge blade has a 
unitary extension 187 mounted on it so that the discharge end 149 is 
substantially engaged with the casing at the discharge opening 110. The 
shield plate of the discharge blade is provided with a corresponding 
extension 188 which is parallel to the cover 100. Since the discharge 
blade extends radially from the axis 31, the discharge opening is disposed 
at a point on the casing radially outwardly of the exit section of the 
discharge blade. The discharge opening thus extends from this point in the 
direction 81 of rotation toward the one of the first blades which is 
adjacent to the discharge blade and is disposed in the direction of 
rotation therefrom. 
With the blades 140, 141, and 142 disposed relative to each other and the 
casing 100 and cover 120 as previously described and as best shown in FIG. 
2, the supply opening 125 is disposed above a point on the upper surface. 
This point is spaced somewhat from the entrance section of the one of the 
first blades 140 which is adjacent to the supply opening and is disposed 
therefrom in the direction 81 of rotation. With this relative disposition 
of the blades, casing, and cover, the discharge blade 142 is disposed in 
the direction of rotation from the exit ends 148 of both the inward path 
guide blades 140 and the outward path guide blades 141. 
The machine 10 is utilized with a fragmentarily represented source 200, 
shown in FIG. 3, of unhulled nuts. The source is disposed so that nuts 
from the source are received into the supply opening 125 as indicated by 
the arrow 201. Typically, this source is a well-known vibratory feeder 
which is adapted continuously to supply the nuts at a selected rate. 
OPERATION 
The operation of the described embodiment of the present invention is 
believed to be clearly apparent, and is briefly summarized at this point. 
In operation, the machine is supplied with unhulled nuts from the source 
200 as indicated by the arrow 201 through the supply opening 125 with the 
disc assembly 60 being rotationally driven in the direction 81 by the 
drive assembly 80. 
The nuts descend gravitationally toward the disc 60 through the supply 
opening 125 and are received onto the surface 66 having the layer of grit 
71. The nuts are gravitationally rested on this surface and are carried by 
the rotation of the disc in the direction 81. The nuts are carried in this 
direction toward the one of the blades 140 adjacent to the supply opening. 
The nuts engage the section of this blade adjacent to its entrance end 
147. Since, as previously described, this blade is angularly related to a 
radius from the axis 31, the nuts are urged by their contact with this 
blade in a first, generally radially inward direction, indicated by the 
adjacent one of the arrows 210, along the blade from the peripheral 
portion 67 of the surface toward its central portion 68 and the axis. As 
the nuts move along the blade, they are tumbled against the blade on the 
surface by its movement toward the blade. This tumbling movement of the 
nuts together with their translational movement along the blade causes the 
hulls of the nuts to be abraded from the shells, kernels or other inner 
portions of the nuts by the grit into substantially smaller fragments. The 
blade guides the nuts therealong until they pass beyond its exit end 148 
while the abraded fragments tend to pass through the corresponding passage 
146 and are thus separated from the nuts. At the exit end 148 of the 
blade, the nuts are no longer guided by the blade and are carried 
circumferentially of the disc in a direction indicated by the 
corresponding arrow 212 through the corresponding passage 172 in the 
direction 81 toward the adjacent one of the blades 141 or 142. 
Similar tumbling and translational movements of the nuts occur at each of 
the inward guide blades 140. The rotation of the disc 60 carries the nuts, 
as indicated by the arrows 212, from each of these blades toward the one 
of the outward guide blades 141 or the discharge blade 142 disposed 
adjacent thereto in the direction of rotation 81. Since the section of 
each of these latter blades adjacent to its entrance end 147 extends 
farther toward the axis 31 than do the inward guide blades, the nuts 
engage this section whereby they are centrifugally urged to travel 
radially outwardly along the blade in a second direction, indicated by the 
numeral 214. This second direction is generally opposite of the direction 
210 and toward the exit end 148 of the corresponding blade. As the nuts 
travel in this direction, they are again tumbled on the surface for 
further abrasive hull-removing and fragmenting action by the grit 71. The 
nuts are guided by each outward guide blade until they pass from it about 
its exit end 148 through the corresponding passage 173 while the abraded 
hulls tend to pass through the corresponding passage 146. 
At this point, the rotation of the disc 60 carries the nuts toward the next 
adjacent one of the inward path guide blades 140 in the direction 81 of 
rotation. The unhulled nuts and kernels are too large to pass through the 
gap 105 and, due to the corresponding hinge 170, cannot bypass this next 
adjacent blade outwardly of its entrance end 147. The nuts and kernels 
are, therefore, urged by the inward guide blade to move again centrally of 
the disc until they pass from the exit end 148 of this blade to the next 
adjacent outward guide blade in the direction 81. As a result, the nuts 
are guided repeatedly to traverse the surface 66 in a reciprocal path of 
movement alternately toward and from the axis 31 by each adjacent pair of 
blades 140 and 141. The abrasive action of the grit 71 and resultant hull 
removal continues as the nuts traverse the disc. Finally, the nuts pass 
from the one of the inward guide blades adjacent to the discharge blade 
142 and disposed in a direction therefrom opposite of the direction of 
rotation 81. The nuts then engage the discharge blade and are guided by it 
toward the discharge opening 110. The abrasive action continues as the 
nuts approach this opening to complete the hull removal occuring while the 
nuts were guided by the blades 140 and 141. The separated kernels are 
guided by the extension 187 of the discharge blade and removed from the 
disc 65 through the discharge opening, as indicated by the arrows 216, 
onto the spout 115 and discharged from the machine 10. 
The path of the nuts, indicated by the arrows 210, 212, 214, and 216, is 
generally in the direction of rotation 81 from the supply opening 125 to 
the discharge opening 110. The overall length of this path is 
substantially constant. However, the time required to travel the path and, 
therefore, the amount of abrasion performed on the hull of each nut can be 
varied by adjusting the angular position of the blades 140, 141, and 142 
about their respective axes 150. The angle of the inward guide blades 140 
can be varied to increase or decrease the component of the force exerted 
by the rotation of the disc in the direction 210, and the corresponding 
slots 157 are disposed so that there is always some such component. The 
angular position of the blades 141 and 142 can be adjustably varied so 
that a component of the force of the disc against the nuts either slightly 
aids or slightly opposes the centrifugal force which always urges the 
tumbled nuts outwardly along these blades. The forces urging the nuts 
along the blades can thus be varied to lengthen or shorten the time the 
nuts remain on the disc 60 to accommodate nuts having hulls of different 
hardness due to the variety of nut or to growing or storage conditions. 
As the hulls are abraded from the shells of the nuts during passage of the 
latter from the supply opening 125 to the discharge opening 110, the hulls 
are broken and pulverized by the action of the grit 71 into fragments 
which are substantially smaller than the shells. The fragments are urged 
centrifugally to move toward the periphery of the disc 65 as indicated by 
the arrows 218. At the periphery, the fragments are gravitationally urged 
through the gap 105 toward the trough 50 between the box 25 and cylinder 
40, as indicated by the arrows 220. The hulls are thus separated from the 
shells containing the kernels which, as previously described, are too wide 
to pass through the gap. 
When the machine 10 is continuously hulling nuts, it is advantageous to 
supply a flow of water through the fitting 130 to the center of the 
surface 66 as indicated by the arrow 222 in FIG. 3. The water is urged 
centrifugally toward the periphery of the disc 65 and is discharged 
gravitationally through the gap 105 into the trough 50. The water thus 
follows the path of the abraded portions of the nut hulls indicated by the 
arrows 218 and 220 and assists in carrying the hulls from the disc. Since 
the water flows over the grit 71 during the abrading of the hulls, the 
water also lubricates the nuts during this process. The rate of flow can 
be selectively regulated or shut off by the valve 132. 
The abraded hull portions and water which are discharged into the trough 50 
can be removed in any suitable manner. However, it is advantageous to 
allow the hulls to flow into the channel 55 with the water where any 
suitable apparatus, not shown, may be utilized to remove the hull portions 
and recirculate the water to the fitting 130. 
As can be seen from the described operation of the machine, it is adapted 
to be continuously supplied with nuts through the supply opening 125 to 
separate the hulls of the nuts from the shells containing the kernels by 
abrasion, and to discharge the separated hulls into the trough 50 while 
discharging the shells containing the kernels through the opening 110. The 
length of time each nut is abraded to remove its hull can be varied by 
selectively adjusting the angular positions of the blades 140, 141, and 
142 about their respective axes 150 by varying the rotational speed of the 
disc 65 with the drive assembly 80. The abrading and separating process 
can be facilitated by supplying a selected flow of water through the 
fitting 130. As a result, the machine is adapted to remove the hulls from 
pistachio nuts and the like although the nuts are supplied at various 
rates and have been grown, harvested, and stored under a variety of 
conditions. 
Although the invention has been shown and described in what is conceived to 
be the most practical and preferred embodiment, it is recognized that 
departures may be made therefrom within the scope of the invention, which 
is not to be limited to the illustrative details disclosed.