FIELD OF THE INVENTION
[0001] The present subject matter relates generally to agricultural harvesters, such
as sugar cane harvesters, and, more particularly, to an improved extractor fan
assembly for an agricultural harvester.
BACKGROUND OF THE INVENTION
[0002] Typically, agricultural harvesters include one or more extractors
configured to separate and remove pieces of debris or thresh from a stream of
harvested crops, such as a stream of sugar cane billets. For example, a sugarcane
harvester often includes a primary extractor positioned near an intake end of an
elevator assembly that conveys crops toward a receiver collecting the crops, and a
secondary extractor positioned near a discharge end of the elevator assembly. For
conventional sugarcane harvesters, both the primary extractor and the second
extractor include an axial flow extractor fan positioned directly in-line with the flow
of debris through the extractor. For instance, the extractor fan typically includes a fan
hub positioned in the center of the extractor, with fan blades extending radially
outwardly from the hub. While conventional extractor fans often provide adequate
performance, room still exists for improving the overall operating efficiency and
performance of extractor fan assemblies.
[0003] Accordingly, an improved extractor fan assembly for use within an
agricultural harvester would be welcomed in the technology.
BRIEF DESCRIPTION OF THE INVENTION
[0004] Aspects and advantages of the invention will be set forth in part in the
following description, or may be obvious from the description, or may be learned
through practice of the invention.
[0005] In one aspect, the present subject matter is directed to an extractor fan
assembly for an agricultural harvester. The fan assembly may include a shaft
extending lengthwise between an upper shaft end and a lower shaft end. The upper
shaft end may be configured to be coupled to a rotational drive source for rotationally
1
driving the shaft. The fan assembly may also include a fan hub coupled to the lower
shaft end of the shaft such that rotation of the shaft rotationally drives the fan hub and
a plurality of fan blades coupled to and extending radially outwardly from the fan
hub. Each fan blade may extend radially between a radially inner end and a radially
outer end and may define a blade surface area. Additionally, the fan assembly may
have an overall fan diameter defined by the radially outer ends of the fan blades that is
associated with a maximum radial cross-sectional area for the fan assembly.
Moreover, a ratio of the maximum radial cross-sectional area for the fan assembly to
the blade surface area of each fan blade ranges from 2.8 to 3.8.
[0006] In another aspect, the present subject matter is directed to an extractor fan
assembly for an agricultural harvester. The fan assembly may include a shaft housing
extending lengthwise between an upper housing end and a lower housing end, with
the upper housing end configured to be coupled to a portion of an extractor housing of
the harvester. The fan assembly may also include a shaft extending lengthwise at
least partially within the shaft housing between an upper shaft end and a lower shaft
end, with the upper shaft end configured to be coupled to a rotational drive source for
rotationally driving the shaft. Additionally, the fan assembly may include a fan hub
coupled to the lower shaft end of the shaft such that rotation of the shaft rotationally
drives the fan hub, with the fan hub including an upstream side and a downstream
side. Moreover, the fan assembly may include a plurality of fan blades coupled to and
extending radially outwardly from the fan hub and an upper hub covering configured
to be installed relative to the downstream side of the fan hub. The upper hub covering
may extend lengthwise between a bottom end positioned adjacent to the downstream
side of the fan hub and a top end spaced apart from the downstream side of the fan
hub. Furthermore, the upper hub covering may define a cone-shaped profile such that
a diameter of the upper hub covering continuously decreases as the upper hub
covering extends from its bottom end to its top end.
[0007] In a further aspect, the present subject matter is directed to an extractor for
removing debris from crops harvested by an agricultural harvester. The extractor may
include an extractor housing extending from an extractor inlet to an extractor outlet,
with the extractor housing defining an airflow channel for directing the debris through
the extractor from the extractor inlet to the extractor outlet. The extractor may also
2
include a fan assembly installed within the extractor housing so as to be at least
partially positioned within the airflow channel. The fan assembly may include a shaft
extending lengthwise between an upper shaft end and a lower shaft end, with the
upper shaft end configured to be coupled to a rotational drive source for rotationally
driving the shaft. The fan assembly may also include a fan hub coupled to the lower
shaft end of the shaft such that rotation of the shaft rotationally drives the fan hub and
a plurality of fan blades coupled to and extending radially outwardly from the fan
hub, with each fan blade configured to be mounted to the fan hub such that the fan
blade is oriented at a blade angle. Moreover, the blade angle may range from 50
degrees to 52 degrees.
[0008] These and other features, aspects and advantages of the present invention
will become better understood with reference to the following description and
appended claims. The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] A full and enabling disclosure of the present invention, including the best
mode thereof, directed to one of ordinary skill in the art, is set forth in the
specification, which makes reference to the appended figures, in which:
[0010] FIG. 1 illustrates a simplified, side view of one embodiment of an
agricultural harvester in accordance with aspects of the present subject matter;
[0011] FIG. 2 illustrates a side view of a portion of the agricultural harvester
shown in FIG. 1, particularly illustrating a schematic view of one embodiment of an
extractor fan assembly installed within the primary extractor of the harvester in
accordance with aspects of the present subject matter;
[0012] FIG. 3 illustrates a detailed, cross-sectional view of one embodiment of the
fan assembly shown in FIG. 2 in accordance with aspects of the present subject
matter;
[0013] FIG. 4 illustrates a bottom view of the fan assembly shown in FIG. 3 as
installed within the extractor housing of the extractor shown in FIG. 2 in accordance
with aspects of the present subject matter;
3
[0014] FIG. 5 illustrates a top perspective view of a fan hub of the fan assembly
shown in FIG. 3 in accordance with aspects of the present subject matter;
[0015] FIG. 6 illustrates a bottom perspective view of the fan hub shown in FIG. 3
in accordance with aspects of the present subject matter;
[0016] FIG. 7 illustrates a cross-sectional view of the fan hub shown in FIG. 5
taken about line 7-7;
[0017] FIG. 8 illustrates a perspective view of one of the fan blades of the fan
assembly shown in FIG. 3 in accordance with aspects of the present subject matter;
[0018] FIG. 9 illustrates a side view of the fan blade shown in FIG. 8;
[0019] FIG. 10 illustrates an end view of the fan blade shown in FIG. 9;
[0020] FIG. 11 illustrates a side view of the fan blades as installed onto the fan
hub of the disclosed fan assembly in accordance with aspects of the present subject
matter; and
[0021] FIG. 12 illustrates a top view of the blade/hub assembly shown in FIG. 11.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Reference now will be made in detail to embodiments of the invention,
one or more examples of which are illustrated in the drawings. Each example is
provided by way of explanation of the invention, not limitation of the invention. In
fact, it will be apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing from the scope or
spirit of the invention. For instance, features illustrated or described as part of one
embodiment can be used with another embodiment to yield a still further
embodiment. Thus, it is intended that the present invention covers such modifications
and variations as come within the scope of the appended claims and their equivalents.
[0023] In general, the present subject matter is directed to an improved extractor
fan assembly for an agricultural harvester, such as a sugarcane harvester.
Specifically, the disclosed fan assembly may provide for improved debris removal
performance at lower rotational speeds, thereby increasing the overall operating
efficiency for the fan assembly. Additionally, in several embodiments, by configuring
the fan blades of the fan assembly in the manner described herein, the fan blades may
have an enlarged blade surface area while maintaining a relatively small radial profile.
4
As such, the increased surface area may allow the blades to maximize the overall
performance of the fan assembly while the smaller radial profile may permit the fan
assembly to be installed within the extractor housings having smaller diameters. In
this regard, when compared to similarly sized, conventional fan assemblies, the
disclosed fan assembly may provide significantly improved performance and
efficiency.
[0024] Referring now to the drawings, FIG. 1 illustrates a side view of one
embodiment of an agricultural harvester 10 in accordance with aspects of the present
subject matter. As shown, the harvester 10 is configured as a sugarcane harvester.
However, in other embodiments, the harvester 10 may correspond to any other
suitable agricultural harvester known in the art.
[0025] As shown in FIG. 1, the harvester 10 includes a frame 12, a pair of front
wheels 14, a pair of rear wheels 16, and an operator's cab 18. The harvester 10 may
also include a primary source of power (e.g., an engine mounted on the frame 12)
which powers one or both pairs of the wheels 14, 16 via a transmission (not shown).
Alternatively, the harvester 10 may be a track-driven harvester and, thus, may include
tracks driven by the engine as opposed to the illustrated wheels 14, 16. The engine
may also drive a hydraulic fluid pump (not shown) configured to generate pressurized
hydraulic fluid for powering various hydraulic components of the harvester. 10.
[0026] Additionally, the harvester 10 may include various components for cutting,
processing, cleaning, and discharging sugar cane as the cane is harvested from an
agricultural field 20. For instance, the harvester 10 may include a topper assembly 22
positioned at its front end to intercept sugar cane as the harvester 10 is moved in the
forward direction. As shown, the topper assembly 22 may include both a gathering
disk 24 and a cutting disk 26. The gathering disk 24 may be configured to gather the
sugar cane stalks so that the cutting disk 26 may be used to cut off the top of each
stalk. As is generally understood, the height of the topper assembly 22 may be
adjustable via a pair of arms 28 hydraulically raised and lowered, as desired, by the
operator.
[0027] Additionally, the harvester 10 may include a crop divider 30 that extends
upwardly and rearwardly from the field 20. In general, the crop divider 30 may
include two spiral feed rollers 32. Each feed roller 32 may include a ground
5
shoe 34 at its lower end to assist the crop divider 30 in gathering the sugar cane stalks
for harvesting. Moreover, as shown in FIG. 1, the harvester 10 may include a knockdown
roller 36 positioned near the front wheels 14 and a fin roller 38 positioned
behind the knock-down roller 36. As the knock-down roller 36 is rotated, the sugar
cane stalks being harvested are knocked down while the crop divider 30 gathers the
stalks from agricultural field 20. Further, as shown in FIG. 1, the fin roller 38 may
include a plurality of intermittently mounted fins 40 that assist in forcing the sugar
cane stalks downwardly. As the fin roller 38 is rotated during the harvest, the sugar
cane stalks that have been knocked down by the knock-down roller 36 are separated
and further knocked down by the fin roller 38 as the harvester 10 continues to be
moved in the forward direction relative to the field 20.
[0028] Referring still to FIG. 1, the harvester 10 may also include a base cutter
assembly 42 positioned behind the fin roller 38. As is generally understood, the base
cutter assembly 42 may include blades (not shown) for severing the sugar cane stalks
as the cane is being harvested. The blades, located on the periphery of the
assembly 42, may be rotated by a hydraulic motor (not shown) powered by the
vehicle’s hydraulic system. Additionally, in several embodiments, the blades may be
angled downwardly to sever the base of the sugar cane as the cane is knocked down
by the fin roller 38.
[0029] Moreover, the harvester 10 may include a feed roller assembly 44 located
downstream of the base cutter assembly 42 for moving the severed stalks of sugar
cane from the base cutter assembly 42 along the processing path. As shown in FIG. 1,
the feed roller assembly 44 may include a plurality of bottom rollers 46 and a plurality
of opposed, top pinch rollers 48. The various bottom and top rollers 46, 48 may be
used to pinch the harvested sugar cane during transport. As the sugar cane is
transported through the feed roller assembly 44, debris (e.g., rocks, dirt, and/or the
like) may be allowed to fall through bottom rollers 46 onto the field 20.
[0030] In addition, the harvester 10 may include a chopper assembly 50 located at
the downstream end of the feed roller assembly 44 (e.g., adjacent to the rearwardmost
bottom and top feed rollers 46, 48). In general, the chopper assembly 50 may be
used to cut or chop the severed sugar cane stalks into pieces or “billets” 51 which may
be, for example, six (6) inches long. The billets 51 may then be propelled towards an
6
elevator assembly 52 of the harvester 10 for delivery to an external receiver or storage
device (not shown).
[0031] As is generally understood, pieces of debris 53 (e.g., dust, dirt, leaves, etc.)
separated from the sugar cane billets 51 may be expelled from the harvester
10 through a primary extractor 54, which is located behind the chopper
assembly 50 and is oriented to direct the debris 53 outwardly from the harvester 10.
Additionally, an extractor fan 56 may be mounted at the base of the primary
extractor 54 for generating a suction force or vacuum sufficient to pick up the debris
53 and force the debris 53 through the primary extractor 54. The debris 53 is then
directed out of and away from harvester 10 via an outlet of the primary extractor 54.
The separated or cleaned billets 51, heavier than the debris 53 being expelled through
the extractor 54, may then fall downward to the elevator assembly 52.
[0032] As shown in FIG. 1, the elevator assembly 52 may generally include an
elevator housing 58 and an elevator 60 extending within the elevator housing 58
between a lower, proximal end 62 and an upper, distal end 64. In general, the elevator
60 may include a looped chain 66 and a plurality of flights or paddles 68 attached to
and evenly spaced on the chain 66. The paddles 68 may be configured to hold the
sugar cane billets 51 on the elevator 60 as the billets 51 are elevated along a top span
of the elevator 70 defines between its proximal and distal ends 62, 64. Additionally,
the elevator 60 may include lower and upper sprockets 72, 74 positioned at its
proximal and distal ends 62, 64, respectively. As shown in FIG. 1, an elevator motor
76 may be coupled to one of the sprockets (e.g., the upper sprocket 74) for driving the
chain 66, thereby allowing the chain 66 and the paddles 68 to travel in an endless loop
between the proximal and distal ends 62, 64 of the elevator 60.
[0033] Moreover, pieces of debris 53 (e.g., dust, dirt, leaves, etc.) separated from
the elevated sugar cane billets 51 may be expelled from the harvester 10 through a
secondary extractor 78 coupled to the rear end of the elevator housing 58. As shown
in FIG. 1, the secondary extractor 78 may be located adjacent to the distal end 64 of
the elevator 60 and may be oriented to direct the debris 53 outwardly from the
harvester 10. Additionally, an extractor fan 80 may be mounted at the base of the
secondary extractor 78 for generating a suction force or vacuum sufficient to pick up
the debris 53 and force the debris 53 through the secondary extractor 78. The
7
separated, cleaned billets 51, heavier than the debris 53 expelled through the
extractor 78, may then fall from the distal end 64 of the elevator 60. Typically, the
billets 51 may fall downwardly through a discharge opening 82 of the elevator
assembly 52 into an external storage device (not shown), such as a sugar cane billet
cart.
[0034] During operation, the harvester 10 is traversed across the agricultural field
20 for harvesting sugar cane. After the height of the topper assembly 22 is adjusted
via the arms 28, the gathering disk 24 on the topper assembly 22 may function to
gather the sugar cane stalks as the harvester 10 proceeds across the field 20, while the
cutter disk 26 severs the leafy tops of the sugar cane stalks for disposal along either
side of harvester 10. As the stalks enter the crop divider 30, the ground shoes 34 may
set the operating width to determine the quantity of sugar cane entering the throat of
the harvester 10. The spiral feed rollers 32 then gather the stalks into the throat to
allow the knock-down roller 36 to bend the stalks downwardly in conjunction with the
action of the fin roller 38. Once the stalks are angled downwardly as shown in FIG. 1,
the base cutter assembly 42 may then sever the base of the stalks from field 20. The
severed stalks are then, by movement of the harvester 10, directed to the feed roller
assembly 44.
[0035] The severed sugar cane stalks are conveyed rearwardly by the bottom and
top feed rollers 46, 48, which compress the stalks, make them more uniform, and
shake loose debris to pass through the bottom rollers 46 to the field 20. At the
downstream end of the feed roller assembly 44, the chopper assembly 50 cuts or
chops the compressed sugar cane stalks into pieces or billets 51. Airborne debris or
chaff 53 (e.g., dust, dirt, leaves, etc.) separated from the sugar cane billets 51 is then
extracted through the primary extractor 54 using suction created by the extractor
fan 56. The separated/cleaned billets 51 then fall downwardly into the elevator
assembly 52 and travel upwardly via the elevator 60 from its proximal end 62 to its
distal end 64. During normal operation, once the billets 51 reach the distal end 64 of
the elevator 60, the billets 51 fall through the discharge opening 82 to an external
storage device. Similar to the primary extractor 54, chaff is blown out from harvester
10 through the secondary extractor 78 with the aid of the extractor fan 80.
8
[0036] Referring now to FIG. 2, a partial side view of the agricultural harvester 10
shown in FIG. 1 is illustrated, particularly illustrating a schematic view of one
embodiment of an extractor fan assembly 100 installed within the primary extractor
54 of the harvester 10 in accordance with aspects of the present subject matter. In
general, the fan assembly 100 will be described herein with reference to being
installed within a harvester’s primary extractor (e.g., as a replacement for fan 56
shown in FIG. 1). However, in other embodiments, the disclosed fan assembly 100
may also be installed within a harvester’s secondary extractor (e.g., as a replacement
for fan 80 shown in FIG. 1).
[0037] As shown in FIG. 2, the extractor 54 may generally include an extractor
housing 84 extending from an extractor inlet (e.g., as indicated by dashed line 86 in
FIG. 2) to an extractor outlet 88. As shown in FIG. 2, the extractor housing 84 may
include an exterior housing wall 90 extending around the outer perimeter of the
housing 84 such that the housing 84 defines an airflow channel 92 between the
extractor inlet 86 and outlet 88 for directing debris 53 through the housing 84 for
subsequent discharge from the extractor 54 via the outlet 88. As such, debris 53
directed into the inlet 86 of the extractor housing 84 may flow through the airflow
channel 92 prior to being discharged from the extractor 54 at the extractor outlet 88.
[0038] Additionally, as shown in FIG. 2, an extractor fan assembly 100 is
positioned within the extractor housing 84. As will be described below, the fan
assembly 100 may include various components, including, but not limited to, a fan
hub 102, a plurality of fan blades 104 coupled to and extending radially outwardly
from the hub 104, a shaft 106 configured to rotationally drive the hub 102 (and, thus,
the blades 104), and a shaft housing 108 encasing the shaft 106. As shown in FIG. 2,
the fan assembly 100 may be installed within the extractor housing 84 such that the
hub/blades are positioned within the airflow channel 92 defined by the housing 84.
For example, an upper portion of the shaft housing 108 may be coupled to a top
portion 94 of the extractor housing 84 to allow the various assembly components to be
suspended from or otherwise supported by the housing 94. Additionally, a rotational
drive source 96, such as hydraulic motor driven by the vehicle’s hydraulic system or
any other suitable motor, may be installed along the top portion 94 of the extractor
housing 84 (e.g., along the exterior of the top portion 94 of the housing 84) and may
9
be rotationally coupled to the shaft 106. As such, the rotational drive source 96 may
rotationally drive the shaft 106, which may, in turn, rotationally drive the hub/blades
to allow the fan assembly 100 to generate a suction force at the extractor inlet 86 that
draws debris 53 upwardly away from the stream of billets 51 expelled from the
chopper assembly 50 and into the airflow channel 92 defined by the extractor housing
84 for subsequent delivery to the extractor outlet 88. The cleaned billets 51 may then
fall onto the elevator assembly 52 for transport to a suitable receiver.
[0039] Referring now to FIGS. 3 and 4, differing views of a specific embodiment
of the extractor fan assembly 100 described above with reference to FIG. 2 is
illustrated in accordance with aspects of the present subject matter. Specifically, FIG.
3 illustrates a cross-sectional view of the fan assembly 100. Additionally, FIG. 4
illustrates a bottom view of the fan assembly 100 shown in FIG. 3, particularly
illustrating the fan assembly 100 as installed within a portion of the extractor housing
84 (e.g., a view from the inlet 86 of the housing 84).
[0040] As indicated above, the fan assembly 100 may generally include a fan hub
102 and a plurality of blades 104 coupled to and extending radially outwardly from
the hub 102. For example, as particularly shown in FIG. 4, the fan assembly 100
includes four circumferentially spaced fan blades 104 extending radially outwardly
from the hub 102. The fan assembly 100 may also include a shaft 106 configured to
rotationally drive the hub/blades, and a shaft housing 108 encasing at least a portion
of the shaft 106. Additionally, the fan assembly 100 may further include various
other components, including, but not limited to, an upper hub covering 110
configured to be installed relative to the top or downstream side 111 of the fan hub
102, a lower hub covering 112 configured to be installed relative to the bottom or
upstream side 113 of the fan hub 102, a support member 114 coupled to the shaft 106
and extending through the lower hub covering 112, and a nose cap 116 installed on
the lower hub covering 114 and supported by the support member 114.
[0041] In general, the shaft housing 108 of the fan assembly 100 may correspond
to a hollow member configured to extend lengthwise between an upper housing end
118 and a lower housing end 120. The upper housing end 118 of the shaft housing
108 may be configured to be coupled to a portion of the extractor housing 84 (e.g., the
top portion 94 of the housing 84 shown in FIG. 2). For example, as shown in FIG. 3,
10
one or more mounting flanges 122 may be positioned at or adjacent to the upper
housing end 118 for coupling the shaft housing 108 to the extractor housing 84.
Additionally, the lower housing end 120 of the shaft housing 108 may be configured
to be positioned at or adjacent to the fan hub 102. For example, as will be described
below with reference to FIGS. 5-7, a portion of the shaft housing 108 disposed at or
adjacent to its lower housing end 120 may be configured to be received within a
central shaft cavity 124 (FIGS. 5 and 7) defined by the hub 102.
[0042] The shaft 106 of the fan assembly 100 may generally be configured to
extend lengthwise within the interior of the shaft housing 108 such that the shaft
housing 108 encases or encircles the shaft 106 along at least a portion of its length.
As shown in FIG. 2, the shaft 106 may generally extend lengthwise between an upper
shaft end 126 and a lower shaft end 128. In one embodiment, a portion of the shaft
106 at or adjacent to its upper shaft end 126 may be accessible at the upper housing
end 118 of the shaft housing 108 to allow the shaft 106 to be coupled to an associated
rotational drive source (e.g., source 96 shown in FIG. 2). For instance, when the
upper housing end 118 of the shaft housing 108 is coupled to the extractor housing 54,
a portion of the shaft 108 may be configured to extend through an opening defined in
the extractor housing 54 at the location of such coupling to allow its upper shaft end
126 to be rotationally coupled to the rotational drive source 96 positioned along the
exterior of the housing 54. Additionally, the lower shaft end 128 of the shaft 106 may
be configured to be coupled to the fan hub 102. For example, as will be described
below with reference to FIGS. 5-7, the hub 102 may include a central mounting wall
130 (FIGS. 5-7) configured to allow the lower shaft end 128 of the shaft 106 to be
coupled to the hub 102.
[0043] As indicated above, the fan assembly 100 may also include an upper hub
covering 110 configured to be installed relative to the top or downstream side 111 of
the fan hub 102 and a lower hub covering 112 configured to be installed relative to the
bottom or upstream side 113 of the fan hub 102. As shown in FIG. 3, the upper hub
covering 110 may be configured to extend outwardly from the downstream side 111
of the fan hub 102 such that the upper hub covering 110 encases or encircles a lower
portion of the shaft housing 108. For example, the upper hub covering 110 may
define a height 132 between a bottom end 134 of the covering 110 configured to be
11
coupled or positioned adjacent to the downstream side 111 of the fan hub 102 and a
top end 136 of the covering 110, with the upper hub covering 110 encasing the lower
portion of the shaft housing 108 along the height 132 defined between its top and
bottom ends 136, 134. Additionally, as shown in the illustrated embodiment, the
upper hub covering 110 may be configured as a conical shaped member such that it
defines a tapered or cone-like profile as it extends vertically between its bottom and
top ends 134, 136. For instance, the cone-shaped covering 110 may be configured to
define an inwardly tapered profile as it extends outwardly from the hub 102 such that
a diameter 138 of the upper hub covering 110 continuously decreases from its bottom
end 134 to its top end 134. Specifically, in a particular embodiment, the cone-shaped
covering may define a taper angle 140 relative to the vertical direction equal to 38.5
degrees. However, in other embodiments, taper angle may generally range from
about 34 degrees to about 43 degrees, such as from about 36 degrees to about 41
degrees, or from about 38 degrees to about 39 degrees, and/or any other subranges
defined therebetween.
[0044] It should be appreciated that, in general, the upper hub covering 110 may
be formed from any suitable material. However, in a particular embodiment, the
upper hub covering 110 may be formed from a suitable metal material, such as steel,
aluminum and/or any other suitable metal.
[0045] As shown in FIG. 3, the lower hub covering 112 may be configured to be
installed relative to the hub 102 such that the covering 112 extends outwardly from
the upstream side 113 of the fan hub 102. For example, the lower hub covering 112
may be configured to extend vertically between a top end 142 configured to be
coupled or positioned adjacent to the upstream side 113 of the fan hub 102 and a
bottom end 144 spaced apart from the upstream side 113 of the fan hub 102.
Additionally, as shown in the illustrated embodiment, the lower hub covering 112
may be configured as a dome-shaped member such that it defines a semi-spherical
profile as it extends vertically between its top and bottom ends 142, 144.
[0046] It should be appreciated that the upper and lower hub coverings 110, 112
may be configured to provide suitable flow surfaces for the flow of air being directed
around the fan hub 102 so as to increase the overall aerodynamic efficiency of the
assembly 100. For example, the lower hub covering 112 may be configured to serve
12
as an aerodynamic, upstream nose for the fan hub 102 such that the flow of air being
directed through the extractor housing 84 is efficiently diverted around the hub 102.
Additionally, the cone-shaped upper hub covering 112 may be configured to define a
transition surface for the airflow flowing past the top or downstream side 111 of the
hub 102.
[0047] As shown in FIG. 3, the support member 114 of the fan assembly 100 may
generally be configured to extend through the lower hub covering 112 and connect to
the nose cap 116 positioned at the bottom end 144 of the covering 112. Specifically,
the support member 114 may generally extend lengthwise between a first end 146 and
a second end 148, with the first end 146 being coupled to the lower shaft end 128 of
the shaft 106 and the second end 148 being coupled to the nose cap 116.
Additionally, as shown in FIGS. 3 and 4, the nose cap 116 may generally define a
dome-shaped profile that is generally complementary to the dome-shape profile of the
lower hub covering 112 such that the nose cap 116 extends adjacent to a portion of the
outer surface of the lower hub covering 112 defined around the bottom end 144 of
such covering 112. In one embodiment, the nose cap 116 may be configured to serve
as a retention or support feature for the lower hub covering 112, such as by vertically
supporting the bottom end 144 of the covering 112 relative to hub 102 via the
connection provided by the support member 114.
[0048] As particularly shown in FIG. 4, the fan assembly 100 may generally have
an overall fan diameter 150 defined by the radially outer ends of the fan blades 104.
In general, the fan diameter 150 may be slightly less than a corresponding inner
diameter 152 of the extractor housing 84 such a radial clearance 154 is defined
between the radially outer ends of each fan blade 104 and the inner surface of the
housing 84. In one embodiment, the radial clearance 154 may correspond to a radial
distance that is greater than 10 millimeters (mm) and less than 21 mm, such as a
distance ranging from about 12 mm to about 19 mm, or from about 14 mm to about
17 mm, or from about 15 mm to about 16 mm, and/or any other subranges
therebetween. In a particular embodiment, the radial clearance 154 defined between
the radially outer ends of each fan blade 104 and the inner surface of the housing 84
may be equal to 15.5 mm plus or minus 2% (e.g., plus or minus 0.3).
13
[0049] Referring now to FIGS. 5-7, several views of the fan hub 102 of the
embodiment of the fan assembly 100 shown in FIGS. 3 and 4 are illustrated in
accordance with aspects of the present subject matter. Specifically, FIG. 5 illustrates
a top perspective view of the fan hub 102 while FIG. 6 illustrates a bottom perspective
view of the fan hub 102. Additionally, FIG. 7 illustrates a cross-sectional view of the
fan hub 102 shown in FIG. 5 taken about line 7-7.
[0050] In general, the fan hub 102 may include an outer hub wall 156 and an inner
hub wall 158 spaced radially inwardly from the outer hub wall 156, with the outer hub
wall 156 generally defining the outer circumference of the hub 102. Additionally, as
shown in the illustrated embodiment, the hub 102 includes a plurality of
circumferentially spaced blade mounting flanges 160 extending radially between the
inner and outer hub walls 158, 156. Specifically, in the illustrated embodiment, the
hub 102 includes four blade mounting flanges 160 extending between the inner and
outer hub walls 158, 156, with the center of each mounting flange 160 being generally
spaced apart from the center of adjacent blade mounting flanges by 90 degrees. As
particularly shown in FIG. 6, each mounting flange 160 may define a mounting side
or face 162 along which a corresponding fan blade 104 of the blade assembly 100 is
configured to be mounted. For example, once the fan blade 104 is placed on or
adjacent to the mounting face 162 of a given mounting flange 160, suitable fasteners
(e.g., bolts) may be inserted through both the fan blade 104 and corresponding
openings 164 defined through the flange 160. A nut or other fastening member may
then be secured to each fastener along the opposed side or face 166 (FIG. 5) of each
flange 160 to secure the blade 104 to the hub 102. As will be described below, the
mounting face 162 of each mounting flange 160 may be angled in the circumferential
direction and/or the axial direction of the hub 102 to allow each fan blade 104 to be
mounted onto the hub 102 at a given blade angle. In addition, the mounting face 162
of each mounting flange 160 may also define an arcuate or curved profile that
generally corresponds to the radius of curvature of the fan blade 102 to allow the
blade 102 to be secured flush against the adjacent mounting face 162.
[0051] Additionally, as shown in FIG. 7, the fan hub 102 may define an openended
shaft cavity 124 extending radially between a central axis 168 of the hub 102
and the inner hub wall 158. The shaft cavity 124 may also be configured to extend
14
axially along the central axis 168 between a lower end defined by a central mounting
wall 130 of the hub 102 and an upper end that is open along the top or downstream
side 111 of the hub 102. As such, the lower shaft end 128 of the shaft 106 (and,
optionally, the lower housing end 118 of the shaft housing 108) may be received
within the shaft cavity 124. In such an embodiment, the lower shaft end 128 of the
shaft 106 may be configured to be coupled to the central mounting wall 130 of the
hub 102 to allow the shaft 106 to be rotationally coupled to the hub 102. For
example, as shown in FIG. 5, the central mounting wall 130 may define a plurality of
fastener openings 170 configured to receive suitable mechanical fasteners for
coupling the shaft 106 to the hub 102, such as by directly coupling the shaft 106 to the
hub 102 via a shaft flange formed integrally with or otherwise coupled to the lower
shaft end 128 of the shaft 106.
[0052] In addition to the upper shaft cavity 124, the fan hub 102 may also define a
lower cavity 172 along the bottom or upstream side 113 of the fan hub 102. For
example, as shown in FIG. 7, the lower cavity 172 may extend radially between the
central axis 168 of the hub 102 and the portion of the inner hub wall 158 extending
axially downwardly from the central mounting wall 130 in the direction of the
upstream side 113 of the hub 102 such that the central mounting wall 130 generally
serves as a divider wall between the shaft cavity 124 and the lower cavity 172. In one
embodiment, the lower cavity 172 may be configured to accommodate the top or first
end 148 of the support member 114 and/or any other suitable components for
supporting the support member 114 relative to the hub 102 and/or for coupling the
primary shaft 106 to the hub 102.
[0053] It should be appreciated that the hub 102 may also include one or more
mounting features for mounting the upper hub covering 110 to the fan hub 102. For
example, as shown in FIG. 5, the hub 102 may include a plurality of mounting tabs
174 spaced circumferentially apart from one another along the top or upstream side
111 of the hub 102, such as by including four mounting tabs 174 spaced apart from
one another by approximately 90 degrees. In such an embodiment, the upper hub
covering 110 may include corresponding mounting features for allowing the hub
covering 110 to be coupled to the hub 102 at each mounting tab 174 via suitable
mechanical fasteners.
15
[0054] Referring now to FIGS. 8-10, several views of one of the fan blades 104 of
the fan assembly 100 described above with reference to FIGS. 3 and 4 are illustrated
in accordance with aspects of the present subject matter. Specifically, FIG. 8
illustrates a perspective view of the fan blade 104 and FIG. 9 illustrates a top view of
the fan blade 104 shown in FIG. 8. Additionally, FIG. 10 illustrates an end view of
the fan blade 104 shown in FIGS. 8 and 9, particularly illustrating the radius of
curvature of the fan blade 104.
[0055] As shown in the illustrated embodiment, the fan blade 104 may generally
be configured to extend radially between an inner endwall 176 defining the radially
inner end of the blade 104 and an outer endwall 178 defining the radially outer end of
the blade 104, with the fan blade 104 defining an overall radial length 180 between
the inner and outer endwalls 176, 178. Additionally, the fan blade 104 may generally
be configured to extend circumferentially between a first circumferential side 182 and
a second circumferential side 184, with the fan blade 104 defining an overall
circumferential width 186 between its first and second circumferential sides 182, 184.
In several embodiments, the fan blade 104 may define a width-to-length ratio
corresponding to the ratio of its circumferential width 186 to its radial length 180 that
is greater than 0.9, such as a width-to-length ratio ranging from 0.9 to 1.3, or a widthto-
length ratio ranging from 1.0 to 1.2, and/or any other subranges therebetween. In a
particular embodiment, the width-to-length ratio may be equal 1.1 plus or minus 5%
(e.g., plus or minus 0.05).
[0056] The fan blade 104 may also include a first blade surface 181 extending
radially between the inner and outer endwalls 176, 178 and circumferentially between
the first and second circumferential sides 182, 184 along a first face of the blade 104
(e.g., the face shown in FIGS. 8 and 9). Additionally, the fan blade 104 may include a
second blade surface 183 (FIG. 10) extending radially between the inner and outer
endwalls 176, 178 and circumferentially between the first and second circumferential
sides 182, 184 along the opposed face of the blade 104. In several embodiments, the
first and second blade surfaces 181, 183 may generally define the blade surface area
for the fan blade 104.
[0057] It should be appreciated that, by configuring the fan blade 104 to have a
significantly large width-to-length ratio (e.g., a ratio of greater than 0.9), the fan blade
16
104 may advantageously have a larger overall surface area without requiring a large
radial profile, thereby allowing the fan blade 104 to be utilized within extractor
housings have smaller diameters. For instance, in one embodiment, when the fan
blade 104 has a radial length 180 ranging from 280 millimeters (mm) to 360 mm, the
fan blade 104 may have a surface area ranging from 160,000 mm2 to 180,000 mm2.
In another embodiment, when the fan blade 104 has a radial length 180 ranging from
300 mm to 340 mm, the fan blade 104 may have a surface area ranging from 165,000
mm2 to 175,000 mm2. Additionally, in a further embodiment, when the fan blade 104
has a radial length 180 ranging from 315 mm to 325 mm, the fan blade 104 may have
a surface area ranging from 168,000 mm2 to 172,000 mm2. In a particular
embodiment, when the fan blade 104 has a radial length 180 of 321 mm, the fan blade
104 may have a surface area ranging of 170,000 mm2.
[0058] As shown in FIG. 9, the fan blade 104 may include a first sidewall 188
extending along its first circumferential side 182 between the inner and outer endwalls
176, 178. In one embodiment, the first sidewall 188 may define a diverging, arcuate
profile as it extends from the inner endwall 176 to the outer endwall 178. As such,
the first sidewall 188 may be shaped so as to provide for an increase in the
circumferential width 186 of the fan blade 104 as it extends towards the outer endwall
178. Additionally, as shown in FIG. 9, the fan blade 104 may define a stepped or
discontinuous profile along its second circumferential side 184. Specifically, the fan
blade 104 includes both a first sidewall portion 190 and a second sidewall portion 192
along its second circumferential side 184, with the first and second sidewall portions
190, 192 being connected by a transition wall portion 194. For example, in the
illustrated embodiment, the first sidewall portion 190 generally extends radially from
the inner endwall 176 to the transition wall portion 194 and generally defines a
straight or non-curved radial profile. In contrast, the second sidewall portion 192
extends radially from the transition wall portion 194 to the outer endwall 178 and
generally defines a diverging, arcuate profile. As such, the second sidewall portion
192 may be shaped so as to provide for an increase in the circumferential width 186 of
the fan blade 104 as it extends from the transition wall portion 194 to the outer
endwall 178. Moreover, as shown in FIG. 9, the transition wall portion 194 may be
configured to extend between the first and second sidewall portions 190, 192 such that
17
the transition wall portion 194 at least partially extends radially inwardly from the
first sidewall portion 190 to the second sidewall portion 192. As such, a radially outer
end 196 of the first sidewall portion 190 terminating at the transition wall portion 194
may be positioned radially outwardly relative to a corresponding radially inner end
198 of the second sidewall portion 192 terminating at the transition wall portion 194.
[0059] It should be appreciated that, in one embodiment, the transition wall
portion 194 may be configured to extend directly adjacent to the outer hub wall 156 of
the fan hub 102 when the fan blade 104 is mounted onto the hub 102. In such an
embodiment, the transition wall portion 194 may, for example, be configured to
define a slightly curved or arcuate profile generally corresponding to the radius of
curvature of the outer hub wall 156 such that the transition wall portion 194 extends
directly adjacent to the outer surface of the outer hub wall 156 along its length
between the radially outer end 196 of the first sidewall portion 190 and the adjacent
radially inner end 198 of the second sidewall portion 192.
[0060] As particularly shown in FIG. 9, the fan blade 104, itself, may generally be
divided into a mounting portion 191 and a blade portion 193. For example, in one
embodiment, the curved or arcuate profile of the transition wall portion 194 may be
projected across the face of the blade 104 (e.g., as indicated by dashed line 195 in
FIG. 9) to divide the mounting portion 191 from the blade portion 193. In such an
embodiment, the mounting portion 191 of the fan blade 104 may generally be
configured to be supported directly by or otherwise positioned adjacent to the fan hub
102 when the blade 104 is coupled to the hub 102, while the blade portion 193 may be
configured to project radially outwardly from the fan hub 102. In this regard, as
shown in FIG. 9, a plurality of blade openings 197 may be defined in the mounting
portion 191 of the blade 104 for coupling the blade 104 to the hub 102. For example,
the blade openings 197 may be configured to be aligned with the associated mounting
openings 164 defined through each blade mounting flange 160 to allow suitable
fasteners to be inserted through the aligned openings 164, 197 to couple the blade 104
to the hub 102.
[0061] As particularly shown in FIG. 10, the fan blade102 may also define a
radius of curvature 199 as the blade 102 extends between its first and second
circumferential sides 182, 184. For example, in one embodiment, the radius of
18
curvature 199 of the blade 104 may range from about 450 millimeters (mm) to about
550 mm, such as from 460 mm to 540 mm, or from 475 mm to 525 mm, or from 490
mm to 510 mm, and/or any other subranges therebetween. In a particular
embodiment, the radius of curvature 199 of the blade 102 may be equal to 500 mm
plus or minus 1% (e.g., plus or minus 5 mm).
[0062] Referring now to FIGS. 11 and 12, differing views of the fan blades 104 as
assembled onto the fan hub 102 of the fan assembly 100 described above are
illustrated in accordance with aspects of the present subject matter. Specifically, FIG.
11 illustrates a side view of the hub/blade assembly, particularly illustrating an end
view of one of the blades 104 as mounted onto the hub 102. Additionally, FIG. 12
illustrates a top view of the hub/blade assembly shown in FIG. 11.
[0063] As particularly shown in FIG. 11, in several embodiments, the fan blade
104 may be configured to be mounted onto the hub at a given blade angle 161. In
general, the blade angle 161 may be defined between a reference plane 163 extending
parallel to and through the central axis 168 of the hub 102 and a tangential reference
line 165 extending tangent to the surface of the fan blade 104 at the location at which
the reference plane 163 intersects the blade surface. In one embodiment, the blade
angle 161 may range from 50 degrees to 52 degrees, such as from 50.2 degrees to
51.8 degrees, or from 50.5 degrees to 51.5 degrees, or from 50.8 degrees to 51.2
degrees, and/or any other subranges therebetween. In a particular embodiment, the
fan angle may be equal to 51 degrees plus or minus 0.5% (e.g., plus or minus 0.25).
[0064] It should be appreciated that, to allow the blade 104 to be oriented at the
above-described blade angle 161, the mounting face 162 of each mounting flange 160
may be oriented at the same or a similar angle. For instance, in one embodiment, the
mounting face 162 of each mounting flange 160 may be oriented at an angle relative
to the reference plane 163 at the location at which the plane 163 intersects the
mounting face 162 that is equal to the blade angle 161. Additionally, as should be
appreciated by the view shown in FIG. 9, the mounting face 162 of each mounting
flange 160 may also define a curve profile generally corresponding to the radius of
curvature 199 of the blade 102, thereby allowing the mounting portion 191 of each
blade 104 to be mounted flush against its corresponding mounting flange 160.
19
[0065] Referring particularly to FIG. 12, as indicated above, the fan assembly 100
may have an overall fan diameter 150 defined by the radially outer ends of the fan
blades 104 (e.g., as represented by circle 167 in FIG. 12). In one embodiment, a ratio
of the maximum radial cross-sectional area of the fan assembly 100 (i.e., the crosssectional
area defined by a circle having a diameter equal to the fan diameter 150,
such as the area within the circle 167 shown in FIG. 12) to the blade surface area of
each fan blade 104 may range from 2.8 to 3.8, such as a ratio ranging from about 3.0
to about 3.6 or from about 3.2 to about 3.5 or from about 3.3 to about 3.4. In a
particular embodiment, the ratio of the maximum radial cross-sectional area of the fan
assembly 100 to the blade surface area of each fan blade 104 may be equal to 3.3 plus
or minus 2% (e.g., plus or minus 0.07).
[0066] In another embodiment, the blade surface area of each fan blade 104 may
also be expressed as a function of the cross-sectional area of the hub 104 (e.g., as
determined by an outer diameter 169 of the hub 102 defined by its outer hub wall
156). For example, in one embodiment, the ratio of the blade surface area of each fan
blade 104 to the cross-sectional area of the hub 102 (e.g., as determined by the outer
hub diameter 169) may range from .098 to 1.18, such as from 1.00 to 1.16, or from
1.05 to 1.11, and/or any other subranges defined therebetween. In a particular
embodiment, the ratio of the blade surface area of each fan blade 104 to the crosssectional
area of the hub 102 may be equal to 1.08 plus or minus 2% (e.g., plus or
minus 0.02).
[0067] As indicated above, in several embodiments, the transition wall portion
194 of each fan blade 104 may be configured to extend lengthwise generally adjacent
to the radially outer surface of the fan hub 102. For example, as shown in FIG. 12,
with the fan blades 104 mounted to the hub 102, the transition wall portion 194 of
each blade 104 extends generally adjacent to the outer circumference of the hub 102
defines by its outer hub wall 156. As a result, the transition wall portion 194 may
allow for the overall circumferential width 186 of the fan blade 104 to be increased by
permitting a portion of the fan blade 104 to wrap circumferentially around the hub
102, which, in turn, allows for the total blade surface area of each blade 104 to be
similarly increased.
20
[0068] It should be appreciated that, in several embodiments, the disclosed fan
assembly 100 may be configured to operate at a given rotational speed to provide
desired performance and/or efficiency, particularly to provide improved performance
over conventional fan assemblies of the same or a similar size. Specifically, in one
embodiment, the fan assembly 100 may be configured to be operated at a rotational
speed ranging from 1350 RPM to 1450 RPM, such as from 1360 RPM to 1440 RPM,
or from 1375 RPM to 1425 RPM, and/or any other subranges therebetween. In a
particular embodiment, the fan assembly may be configured to be operated at a
rotational speed equal to 1400 RPM plus or minus 0.5% (e.g., plus or minus 7 RPM).
[0069] This written description uses examples to disclose the invention, including
the best mode, and also to enable any person skilled in the art to practice the
invention, including making and using any devices or systems and performing any
incorporated methods. The patentable scope of the invention is defined by the claims,
and may include other examples that occur to those skilled in the art. Such other
examples are intended to be within the scope of the claims if they include structural
elements that do not differ from the literal language of the claims or if they include
equivalent structural elements with insubstantial differences from the literal language
of the claims.

WHAT IS CLAIMED IS:
1. An extractor fan assembly for an agricultural harvester, the extractor
fan assembly comprising:
a shaft extending lengthwise between an upper shaft end and a lower shaft
end, the upper shaft end configured to be coupled to a rotational drive source for
rotationally driving the shaft;
a fan hub coupled to the lower shaft end of the shaft such that rotation of the
shaft rotationally drives the fan hub; and
a plurality of fan blades coupled to and extending radially outwardly from the
fan hub, each fan blade extending radially between a radially inner end and a radially
outer end and defining a blade surface area;
wherein:
the fan assembly has an overall fan diameter defined by the radially outer ends
of the fan blades that is associated with a maximum radial cross-sectional area for the
fan assembly; and
a ratio of the maximum radial cross-sectional area for the fan assembly to the
blade surface area of each fan blade ranges from 2.8 to 3.8.
2. The extractor fan assembly of claim 1, wherein the ratio of the
maximum radial cross-sectional area for the fan assembly to the blade surface area of
each fan blade is equal to 3.3 plus or minus 2%.
3. The extractor fan assembly of claim 1, wherein the fan hub defines an
outer diameter associated with a cross-sectional area of the fan hub, wherein a ratio of
the blade surface area of each fan blade to the cross-sectional area of the fan hub
ranges from 0.98 to 1.18.
4. The extractor fan assembly of claim 1, wherein each fan blade defines
a radial length between its radially inner and outer ends, each fan blade further
extending circumferentially between a first circumferential side and a second
circumferential side, each fan blade defining a circumferential width between its first
and second circumferential sides.
5. The extractor fan assembly of claim 4, wherein each fan blade defines
an arcuate profile along its first circumferential side and a discontinuous or stepped
profile along its second circumferential side.
22
6. The extractor fan assembly of claim 5, wherein each fan blade includes
a first sidewall portion and a second sidewall portion extending along its second
circumferential side, the first and second sidewall portions being connected by a
transition wall portion, the first sidewall portion extending radially between the
radially inner end of the fan blade and the transition wall portion, the second sidewall
portion extending radially between the transition wall portion and the radially outer
end of the fan blade, the transition wall portion being oriented at least partially
radially inwardly between the first and second wall portions such that a radially outer
end of the first sidewall portion is positioned radially outwardly from a radially inner
end of the second sidewall portion.
7. The extractor fan assembly of claim 6, wherein the transition wall
portion is configured to extend circumferentially adjacent to a portion of an outer
circumference of the fan hub between the radially outer end of the first sidewall
portion and the radially inner end of the second sidewall portion.
8. The extractor fan assembly of claim 3, wherein a ratio of the
circumferential width of each fan blade to the radial length of each fan blade ranges
from 0.9 to 1.3.
9. The extractor fan assembly of claim 2, wherein, when the radial length
of each fan blade ranges from 300 millimeters (mm) to 340 mm, the blade surface
area of each fan blade ranges from 165,000 mm2 to 175,000 mm2.
10. The extractor fan assembly of claim 1, wherein each fan blade is
configured to be mounted to the fan hub such that the fan blade is oriented at a blade
angle, the blade angle ranging from 50 degrees to 52 degrees.
11. The extractor fan assembly of claim 1, wherein the fan hub includes an
upstream side and a downstream side, further comprising an upper hub covering
configured to be installed relative to the downstream side of the fan hub, the upper
hub covering extending lengthwise between a bottom end positioned adjacent to the
downstream side of the fan hub and a top end spaced apart from the downstream side
of the fan hub, the upper hub covering defining a cone-shaped profile such that a
diameter of the upper hub covering continuously decreases as the upper hub covering
extends from its bottom end to its top end.
12. The extractor fan assembly of claim 11, wherein the upper hub
covering defines a taper angle, the taper angle ranging from 36 degrees to 41 degrees.
13. An extractor fan assembly for an agricultural harvester, the extractor
fan assembly comprising:
a shaft housing extending lengthwise between an upper housing end and a
lower housing end, the upper housing end configured to be coupled to a portion of an
extractor housing of the harvester;
a shaft extending lengthwise at least partially within the shaft housing between
an upper shaft end and a lower shaft end, the upper shaft end configured to be coupled
to a rotational drive source for rotationally driving the shaft;
a fan hub coupled to the lower shaft end of the shaft such that rotation of the
shaft rotationally drives the fan hub, the fan hub including an upstream side and a
downstream side;
a plurality of fan blades coupled to and extending radially outwardly from the
fan hub; and
an upper hub covering configured to be installed relative to the downstream
side of the fan hub, the upper hub covering extending lengthwise between a bottom
end positioned adjacent to the downstream side of the fan hub and a top end spaced
apart from the downstream side of the fan hub, the upper hub covering defining a
cone-shaped profile such that a diameter of the upper hub covering continuously
decreases as the upper hub covering extends from its bottom end to its top end.
14. The extractor fan assembly of claim 13, wherein the upper hub
covering defines a taper angle, the taper angle ranging from 36 degrees to 41 degrees.
15. The extractor fan assembly of claim 13, wherein each fan blade
extends radially between a radially inner end and a radially outer end and defines a
blade surface area, the fan assembly having an overall fan diameter defined by the
radially outer ends of the fan blades that is associated with a maximum radial crosssectional
area for the fan assembly, wherein a ratio of the maximum radial crosssectional
area for the fan assembly to the blade surface area of each fan blade is equal
to 3.3 plus or minus 2%.
16. The extractor fan assembly of claim 13, wherein each fan blade defines
a radial length between its radially inner and outer ends, each fan blade further
24
extending circumferentially between a first circumferential side and a second
circumferential side, each fan blade defining a circumferential width between its first
and second circumferential sides.
17. The extractor fan assembly of claim 16, wherein each fan blade
includes a first sidewall portion and a second sidewall portion extending along its
second circumferential side, the first and second sidewall portions being connected by
a transition wall portion, the first sidewall portion extending radially between the
radially inner end of the fan blade and the transition wall portion, the second sidewall
portion extending radially between the transition wall portion and the radially outer
end of the fan blade, the transition wall portion being oriented at least partially
radially inwardly between the first and second wall portions such that a radially outer
end of the first sidewall portion is positioned radially outwardly from a radially inner
end of the second sidewall portion.
18. The extractor fan assembly of claim 16, wherein, when the radial
length of each fan blade ranges from 300 millimeters (mm) to 340 mm, the blade
surface area of each fan blade ranges from 165,000 mm2 to 175,000 mm2.
19. The extractor fan assembly of claim 1, wherein each fan blade is
configured to be mounted to the fan hub such that the fan blade is oriented at a blade
angle, the blade angle ranging from 50 degrees to 52 degrees.
20. An extractor for removing debris from crops harvested by an
agricultural harvester, the extractor comprising:
an extractor housing extending from an extractor inlet to an extractor outlet,
the extractor housing defining an airflow channel for directing the debris through the
extractor from the extractor inlet to the extractor outlet; and
a fan assembly installed within the extractor housing so as to be at least
partially positioned within the airflow channel, the fan assembly comprising:
a shaft extending lengthwise between an upper shaft end and a lower
shaft end, the upper shaft end configured to be coupled to a rotational drive
source for rotationally driving the shaft;
a fan hub coupled to the lower shaft end of the shaft such that rotation
of the shaft rotationally drives the fan hub; and
a plurality of fan blades coupled to and extending radially outwardly
from the fan hub, each fan blade configured to be mounted to the fan hub such
that the fan blade is oriented at a blade angle,
wherein the blade angle ranges from 50 degrees to 52 degrees.