Separation Device for Hazelnut Kernels and Shells
Name
Signature
Signature Date
Expected
Graduation
Caynen Klessig
Dec, 2015
Kathleen Roush
May, 2017
Rebecca L. Smith
May, 2016
Haohua (Mandy)
Wang
May, 2016
David R. Bohnhoff
4/27/16
Separation Device for Hazelnut Kernels and Shells Page 2 Separation Device for Hazelnut Kernels and Shells
Abstract
Acknowledgements
The separation of hazelnut kernels from their shells
following the hazelnut being cracked is a vital step in
hazelnut processing. As hazelnut production
increases in the Midwest, a compact, clean, and cost
effective system is needed to accomplish the shell
and kernel separation processing step. Our team has
designed a separation device that will provide an
efficient, safe and cost effective alternative to
hazelnut kernel and shell separation for the American
Hazelnut Company. The design features a selffeeding system, a turbulent flow inducing zig-zag
aspirator, variable air velocity control for adjusting
levels of separation, and a cyclone dust separator to
ensure clean air in the work space.
The team would like to acknowledge our project
advisor, Professor David Bohnhoff, for his
continuous encouragement, guidance and financial
support throughout the project.
We would also like to thank Kuhn North America
Inc. for graciously painting our project at no cost to
us. The paint is what gives the project a very
professional look.
Key Words








Hazelnut Processing
Midwest Agriculture
American Hazelnut Company
Aspirator
Shell and Kernel Separator
Specific Surface Area
Aspirator Solid Separation
Filbert
Separation Device for Hazelnut Kernels and Shells Page 3 Table of Contents
Title Page
Abstract, Acknowledgements and Keywords
Table of Contents
Introduction
Midwest Hazelnut Industry
American Hazelnut Company
Separation Techniques
Development Work at UW-Madison
Project Goal Statement
Design Specifications
Overall Design and Approach
Basic Components
Purchase Versus Fabricating
Design Sequence
Modular Design
Design Alternatives and Selection
Cyclone
Collection Box
Motor and Fan
Main Frame
Transition Ductwork and Air Inlet Valve
Aspirator
In-Feed System
Fabrication
Testing
Economics
Safety
Durability
Achievement of Objectives
References
Appendices
A. Fan Measurements and Testing
B. Cyclone Design
C. Cyclone Simulations
D. Structural analysis
E. Material Costs
F. Process Flow
1
2
3
4
4
4
5
6
6
6
7
7
7
8
8
8
8
9
10
10
11
12
12
13
16
16
16
17
17
17
18
20
22
23
25
27
Separation Device for Hazelnut Kernels and Shells Page 4 Introduction
Midwest Hazelnut Industry
In 2007, a group of hazelnut researchers and growers
in Wisconsin, Minnesota and Iowa formed the Upper
Midwest Hazelnut Development Initiative (UMHDI).
The goal of the UMHDI is to establish an
economically sustainable and eco-friendly hazelnut
industry for the Upper Midwest.
Since its founding, the UMHDI has worked to
develop hazelnut cultivars that are cold hardy,
resistant to Eastern Filbert Blight (EFB), and as
productive as cultivars grown in Europe and
northwest United States. The UMHDI has also
served as a educational source for farmers interested
in growing hazels.
American Hazelnut Company
In 2014, the UMHDI helped establish the American
Hazelnut Company (AHC) - a grower-owned
hazelnut processing and marketing cooperative.
For the past two years, the AHC has purchased
hazelnuts from WI, MN and IA growers, cracked
them, separated the kernels from the shells, and made
oil and flour from some of the kernels. Figure 1
shows whole nuts, the mixture of shells and kernels
resulting from cracking, and kernels after separation.
Figure 2 shows a sample pack of hazelnut kernels, oil
and flour as produced by the AHC.
To meet current State and federal laws governing
food safety, this processing was done in a Statelicensed incubator kitchen in Gays Mills, WI. While
the cost of utilizing the incubator kitchen was
relatively low, the cost of processing the nuts in the
kitchen was relatively high due to the large amount of
hand-sorting required to separate hazelnut kernels
from their shells.
It is clear to the AHC that to produce products that
can be sold at competitive prices, the co-op must
significantly reduce manual labor by incorporating
specialized sorting equipment into their operation.
Given that no one piece of equipment can do a
perfect job of separating kernels from their shells, the
AHC envisions that they will use a series of devices,
each of which differs in the material property that it
exploits in the separation process.
With respect to equipment size and/or capacity, the
AHC does not need large equipment (the Midwest
hazelnut industry is in its infancy and has only been
able to obtain a few hundred pounds of nuts to date),
does not have room for large equipment (space in the
incubator kitchen is extremely limited), and cannot
Figure 1. Hazelnuts before (top) and after cracking (middle),
and kernels (bottom) after shell and kernel separation
afford large equipment (as a start-up, the AHC has
limited working capital).
Separation Device for Hazelnut Kernels and Shells Page 5 Figure 2. American Hazelnut Company sample pack from
http://www.americanhazelnut.co/the-products.html
Figure 4. Rotating drum sizer.
Separation Techniques
Separation techniques can be categorized based on
the material property exploited in the separation
process. The most commonly exploited properties
are size, shape, density, specific surface area, and
color.
Size separators exploit the linear dimensions of the
material. Common size separators include roller
sizers (Figure 3), rotating drum sizers (Figure 4) and
vibratory screens (Figure 5).
Figure 5. Vibratory screen sizer from
http://vibroflow.com.au/vibratory-equipment/screens.php
Shape separators exploit significant differences in the
relative shape of particles. With respect to hazelnut
kernel and shell separation, a shape separator may
exploit the fact that shell fragments are less likely to
roll than are kernels. Variations in shape are
commonly exploited by image processing equipment
used in separation processes.
Figure 3. Roller sizer fabricated at the University of
Wisconsin-Madison for the AHC.
Separators that exploit density will typical utilize a
liquid in the separation process – a liquid whose
density is between those of the particles being
separated. When working with food substances, the
introduction of a liquid onto the food surface
typically creates more problems than it solves and/or
drives up costs appreciably. It should also be noted
that water cannot be used to separate hazelnut kernels
and shells on the basis of density alone as both are
denser than water.
Specific surface area is the surface area of a particle
divided by its mass. This material property is
Separation Device for Hazelnut Kernels and Shells Page 6 exploited in pneumatic aspirator separators which are
devices that introduce material to be separated into an
upward moving column of air. An increase in air
velocity increases the upward acting drag force
applied to the particle. If this drag force exceeds the
mass-dependent, downward-acting gravitational
force, the particle will move upward (Figure 6). Drag
force is largely a function of surface area, but is also
dependent on particle shape and relative orientation
and location within the air stream. Figure 7 shows a
pair of aspirator separators being used to separate
hazelnut kernels and shells in the Willamette Valley
of Oregon. Figure 8 shows a low cost system
developed by Jason Fischbach for separating hazelnut
husks from nuts, and for separating hazelnut kernels
from shells.
Color is commonly exploited to separate materials in
the food industry. Systems that rely on color typically
include image processing hardware and software and
are relatively expensive.
Figure 8. Low cost aspirator separator by Fischbach (2015).
Development Work at UW-Madison
Figure 6. Forces applied to shells and kernels inside the
aspirator column.
To date, students and staff at the University of
Wisconsin-Madison have built a hazelnut husker, a
hazelnut cracker, and a roller sizer (the latter is
shown in Figure 3 and is in use by the AHC). UWMadison has also designed and is currently
fabricating a rotating drum sizer, and two different
student design teams have just begun work on kernel
and shell separators that exploit shape. Our
assignment was to design a pneumatic aspirator
separator.
Project Goal Statement
The goal of this project was to design and create a
safe, efficient, small scale, and affordable pneumatic
aspirator separator for hazelnut kernels and shells.
Design Specifications
Based on our research and necessity, we established
the following initial design specifications at the
beginning of the design process.
Capacity:
Figure 7. Dual bottom-fed aspirating columns in use at
Denfeld Packing Company, Hillsboro, Oregon.
 Separator should be able to separate 500 lbm of
shell/kernel mixture per hour.
Cost:
 Total material costs should not exceed $2500.
Separation Device for Hazelnut Kernels and Shells Page 7 Dimensions:
Performance:
 Separator must fit through a net opening that is 33
inches wide and 82 inches high without the need to
disassembly any portion of the unit. This
specification is required to ensure the unit can be
moved through a nominal 34- by 84-inch door.
 Separation efficiency should be such that when
material is reran through the unit without changing
the settings, 98% of particles end up in the same
collection bin.
 Separator length shall be such that the unit can be
easily transported in a pick-up truck with a bed
length of 7 feet.
Electricity:
 Separator must be designed so that it does not
require more than one single-phase 120V 20
ampere circuit.
Mobility:
 Separator must be easy for one person to move on
any flat and hard surface.
Operation:
 No more than one individual shall be required to
operate the separator continuously and effectively.
 Separator should remain stationary during
operation.
 Separator shall enable the collection of shells and
kernels into HDPE containers with diameters and
heights near 2 foot.
 Separator must have a means to easily adjust the
airflow rate within the aspirating column.
Safety:
 All direct food contact surfaces must meet
requirements for food contact surfaces as specified
in Sanitary Design and Construction of Food
Equipment Standards (Seiberling, 1973).
 Separator operators must not be exposed to TWA
noise levels greater than 90 dB for 8-hour. If noise
level is greater than 90 dB/8-hrs employees must
wear hearing protection in accordance to OSHA
(2015) standard 1910.95.
 Rotating parts, nip-points, and flying chips must be
guarded in accordance with OSHA (2015) standard
1910.212.
 Separator must produce minimal dust to the
surrounding air (less than 10 mg/cubic meter),
following American Conference of Governmental
Industrial Hygienists Guideline (OSHA, 2012).
 Separator must be modular and easy to clean,
ensuring simple maintenance and sanitation.
Overall Design and
Approach
Basic Components
The general components of a pneumatic aspirator
separator are relatively fixed. They include an infeed hopper that houses the mixture of shells and
kernels to be separated, a method for feeding this
mixture to the air aspirating column (herein simply
referred to as the aspirator), the aspirator that is used
to separate the kernels from the shells, a cyclone that
is used to remove shells and any other small particles
from the airstream that is exiting the aspirator, a
motorized fan for moving air through the system, a
method for adjusting the rate of airflow in the system,
a collection bin for the kernels that fall out of the
aspirator, and a bin for material removed by the
cyclone.
Purchase Versus Fabricate
Some of the very first decisions that we made
centered around which items would be purchased,
and which we would fabricate.
Although numerous cyclone-based dust collection
systems are available for purchase, they either did not
fit our dimensional restraints, were too expensive,
were not flexible from an overall layout perspective,
or likely won't meet our airflow requirements. We
thus decided that we would fabricate our own
cyclone.
We purchased an inexpensive dust collection system
that included a motor, fan and filter bag. While we
thought about using the filter bag as a secondary
filtering mechanism, we decided against it very early
in the design process. Instead, we opted to include a
long duct in our design for channeling the air exiting
our cyclone directly to the outside of the building.
This was done for both health, performance, and
practical reasons. From a health perspective,
extremely fine particles still make it through a filter
bag, and thus such filter bags, if used, should be
located outside. From a performance perspective, the
operating characteristics of a separator change as the
filter begins to clog, and this in turn requires
continual adjustments to the system. From a practical
perspective, tests in our lab with other hazelnut
processing equipment has shown that the amount of
Separation Device for Hazelnut Kernels and Shells Page 8 material removed by a filter bag is insignificant when
the cyclone is properly designed.
Because of the need to carefully and quickly control
the flow rate of material into the aspirator, a decision
was made to purchase the vibratory feeder shown in
figure 9. This and similar units are widely used in
the food industry for feeding materials with a
consistency similar to the hazelnut shell and kernel
mixture. While this purchase put a good dent in our
overall budget, we felt confident we would not have
any issues using it to feed our aspirator.
Figure 9. Syntron magnetic feeder (Model F-101-A).
The next main step in the design process was to
determine the airflow characteristics of the fan we
had purchased. These characteristics, along with
both measured and predicted flow resistances of
ductwork and a cyclone, were used to determine
likely system airflow volumes and velocities. This
experimental work is covered in Appendix A. With
this information in hand, we were able to size out
cyclone.
It was obvious for the start of the project that our
height restriction was going to dictate much of the
design. This became more apparent as we started
sizing our cyclone. At one point, we had even
considered moving the collection bin from
underneath the cyclone and adding an elevator
between the cyclone and bin. As detailed in the
following sections, we where able to design a cyclone
and collection bin combination that avoided this
scenario.
Once the cyclone and collection bin designs were set,
we focused on the ductwork connecting the cyclone
to the aspirator. This transition area contains the inlet
valve for controlling airflow. This transition
ductwork with its valve somewhat dictated the
location of the aspirator, so once it was designed, the
location of the aspirator and in-feed hopper were
established and those units were designed.
Design Sequence
Modular Design
After our design specifications were set, we
brainstormed various options for the relative location
of the main components required. Figure 10 shows
an initial conceptual layout by one of our group
members.
We designed the entire system so that individual
units bolted together, and thus could be easily
removed and replaced within the separator something we knew would be advantageous during
initial product design and testing. This approach not
only benefited our testing, but it enabled us to start
some of our fabrication before completing some
design details. More specifically, frame and collector
box fabrication started soon after cyclone and airinlet valve designs were completed. In the end, this
approach to concurrent design and manufacturing
served us critical time.
Design Alternatives and
Selections
Cyclone
Figure 10. An initial conceptual schematic of the separator.
Items in green contain food contact surfaces.
The first major step in our design process was to size
our cyclone. For this we relied on sizing procedures
published by Bill Pentz’s on his website at
http://billpentz.com/woodworking/cyclone/ design.
The main variable controlling cyclone sizing is
airflow. As previously noted, we determined this
Separation Device for Hazelnut Kernels and Shells Page 9 through actual laboratory testing, the results of which
are given in Appendix A.
covered in Appendix C, showed that our change
should not negatively impact cyclone performance.
As shown in Appendix B, our initial calculations
resulted in a cyclone height of just under 50 inches
not including the outlet duct at the top of the cyclone.
To stay under our overall maximum height
requirement of 82 inches, and still have sufficient
room under our cyclone for shell storage, we decided
to direct the exiting air out the side and not the top of
the cyclone. Typical cyclones (and those fabricated
in strict accordance with Bill Pentz's plans) have an
outlet pipe that begins midway into the cone portion
of the cyclone and extends straight out the top of the
upper cylinder of the cyclone. Our solution was to
put a bend in this vertical pipe (at a location just
above the helical ramp that wraps around inside of
the upper cylinder) and have it exit out the side of the
cylinder as shown in figure 11. Note that to match the
5-inch diameter of our blower inlet, a 8.5-to-5.0 inch
reducer was fitted into the vertical pipe inside the
cyclone.
The cyclone was constructed so that the upper
cylinder portion could be unbolted from the lower
cone portion should we decide to install a blast plate
in the upper portion for noise reduction. Also, the
lower portion of the cone was fitted with a special
bolting flange so that it could be quickly attached and
detached from the collection box. Similarly, the inlet
to the cyclone was fitted with a bolting flange so that
the cyclone and ductwork leading to the cyclone
could be easily connected and taken apart.
Collection Box
The cyclone rests on an air-tight collection box that
houses a removable polyethylene collection barrel
(figure 12). Several different designs were mulled
over, with the goal of having a structural sound box
requiring minimal welding. For this reason, we
decided to bend up the three sides of the box from a
single piece of 16 gage steel, and to bend in two ribs
on each side for additional strength. Ribs were not
bent into the top and floor of the box, instead two
reinforcing splines were welded under both the top
and floor of the box.
Figure 12. Rear view of collection box
Figure 11.. Cut away of cyclone showing reducer and
horizontal outlet pipe (left) and outer appearance of cyclone
(right).
To ensure that our major change to Bill Pentz's
cyclone design would not affect the overall
performance of the cyclone, we conducted some CFD
(computation fluid dynamics) simulations of the
cyclone. The results of these simulations, which are
As shown in figures 12 and 13, the box opens to the
rear of the machine. This enables the machine to be
operated in a narrow space. The door hinges were
placed on the left side so that hose that carries the
exhaust air from the unit does not interfere with door
operation (figure 13).
The collection bin was designed around the HDPE
containers, which were cut from barrels that formerly
contained dairy equipment sanitizers. The barrels
were obtained at no charge and cut down to a height
of 22 inches. When filled with shells, these
containers have a mass between 150 and 200 lbm.
Separation Device for Hazelnut Kernels and Shells Page 10 Motor and Fan
The blower fan and motor associated with most
cyclones are located on top of the cyclone. Because
of our height restrictions, this was not an option.
After playing with a couple different locations, we
settled on a spot just in front of the cyclone and a few
inches below the cyclone outlet as shown in figure
14. In the end, this location limited hose length and
did not force us to extend our frame length.
Main Frame
A schematic of our final frame weldment is shown in
figure 15. Two basic frame options were considered:
the rigid frame design we selected, and a slightly
lighter truss-frame design fabricated from lighter
angles and rod cross-bracing. In the end, the rigid
frame was selected because of its more open design
and fewer pieces.
As figure 15 shows, the collector box was
incorporated into the main frame weldment and thus
provided additional rigidity to the assembly.
The frame was designed such that all components
attached to it are centered on the device and fully
supported.
Frame design was complete we started fabricating it
by welding the collector box to the base plate and
building up from there.
Figure 13. Rear view of unit with collection box door open
and containers ready for filling.
Figure 14. Fan location was selected to minimize hose
length and bends between the cyclone and the fan.
Figure 15. Final main frame design
Separation Device for Hazelnut Kernels and Shells Page 11 Transition Ductwork and Air Inlet
Valve
Based on airflow calculations and information from
individuals operating units like that shown in figure
8, it was decided that the top of the aspirator column
should have dimensions of 1.5- by 10-inches. We
then set about developing ductwork to transition from
this size to the 4.25-by 8.5 inch cyclone inlet,
recognizing the need for an air inlet valve within this
ductwork.
has a rectangular opening and the steel housing a
pentagon shaped opening. The amount of air let into
the ductwork is simply controlled by rotating the
PVC pipe inside the fixed housing as shown in figure
17.
With respect to an air inlet, we initially considered
purchasing one or two large PVC ball or gate valves,
but instead opted for our own unique design that was
not only less expensive, but better from a
performance perspective. The valve, which appears
in figure 14, takes air from both sides of the
ductwork, and introduces it across the ductwork in a
direction that facilitates movement of material toward
the cyclone.
Figure 17. Fully open (top) and partially open (bottom)
positions of the air inlet valve.
Our original design had the inlet valve located below
the airflow stream (figure 18). We moved the valve
to a location above the airflow stream (figure 19)
over concern that our initial location could result in a
buildup of dust and shell fragments under some
conditions, causing flow issues and food safety
concerns.
Figure 16. PVC component (top) and steel component
(bottom) that comprise the air inlet valve.
The inlet valve itself consists of a piece of 4-inch
diameter PVC tube that rotates inside a round steel
housing that is welded into the ductwork. These two
parts are shown in figure 16. Note that the PVC pipe
Figure 18. Poor air inlet valve location.
Separation Device for Hazelnut Kernels and Shells Page 12 Figure 19. Final air inlet valve location.
Aspirator
The aspirator design is the defining feature of our
separation device and one we continue to work on.
Our basic approach was to move away from the
bottom-fed, straight column aspirators used in the
Willamette Valley (figure 7) to a middle- or top-fed
zig-zag column similar to those shown in figures 20
and 21, respectively.
Figure 21. Top fed zigzag aspirator. US Patent number
1,279,308 (1918).
Our primary issue with bottom-fed aspirators is edge
effects at the base of the column produce too much
variation in air velocities across the base of the
column. Our primary issue with straight columns is
that there is not enough air mixing within the
aspirator. Both issues produce less consistent (i.e.,
repeatable) separation.
Our overall height restrictions dictated we utilize a
middle feed design. This design provides ample time
for falling shells that begin to fall back down the
aspirator to be knocked into a high air velocity
stream, reverse direction and exit out of the top of the
aspirator while at the same time reducing the distance
the kernels travel to the collection bin, minimizing
damage to the kernels.
Our original aspirator design is shown in figure 22.
This is the first of a couple designs that we plan on
testing. To this end, you will note that we have used
food-grade materials, instead opting for inexpensive
materials including wood for our investigations.
In-Feed System
Figure 20. Middle fed zigzag aspirator. US Patent
number 4,699,049 (1987)
To use a middle-feed aspirator effectively, virtually
no air should enter the aspirator column along with
the material. This requirement significantly
increased the complexity of the overall in-feed
system as it forced us to place the vibratory feeder in
an air-tight container and to make the hopper/bin airtight.
Separation Device for Hazelnut Kernels and Shells Page 13 Figure 23. Hopper suspended inside the air-tight enclosure.
Figure 22.. Original zig-zag aspiration.
After vacillating on a couple designs -- one that
included a circular plastic hopper and another that
included a partially enclosed rectangular hopper with
an air-tight cover -- we settled on a rectangular
hopper that was completed enclosed (along with the
vibratory feeder) in an airtight enclosure. In this
respect, the in-feed hopper was treated much like the
shell collection containers.
The principal advantage of the design we selected is
that overall hopper design is simplified as it only
needs to be suspended within the air-tight enclosure.
Given that the ultimate plan is to fabricate the hopper
from stainless steel (since it needs to meet
requirements for a food contact surface), simple
fabrication is important.
Figure 23 contains an image of the hopper as
fabricated and suspended inside the air-tight
enclosure. This sample version of the hopper was
fabricated from 18 gage low-carbon steel.
Figure 24 shows the air-tight enclosure. Note that the
cover on this enclosure consists of two parts; one that
is fixed, the other that is hinged to this fixed part and
thus facilitates filling of the hopper.
Figure 24. Air-tight enclosure without the plastic door that
helps encloses the vibratory feeder.
The shape of the hopper was designed using
guidelines provided in an FMC Technologies
publication titled “Working With Hoppers”.
Specifically, the rear wall was sloped at an angle of
60 degrees and the front wall at an angle of 55
degrees, the gate height was fixed at 3 inches and the
throat opening at just under 2 inches. These
dimensions reduce build up in the hopper and on the
shaker pan, result in a uniform flow out of the
hopper, and increase the capacity of the system.
Fabrication
Outside of our purchased items, we fabricated all
parts in the Biological Systems Engineering shop
with the help of our advisor Professor Bohnhoff who
did the bulk of the welding.
Separation Device for Hazelnut Kernels and Shells Page 14 For most of us, this was the first time we used a press
brake, powered shears, roll former and an ironworker.
We also used angle grinder, band saws, drill presses,
lathes, plasma cutter and an assortment of hand tools.
Figures 25 through 32 contain fabrication related
images. Needless to say, fabricating our designs was
fulfilling and thus a rewarding experience. We
quickly learned that many of our original designs
could simply not be manufactured with the
equipment we had available. We also learned of the
tradeoffs between metal thickness, amount of weld,
and welding distortion.
Figure 27. Completion of collection box being welded to the
bottom plate.
Figure 25. Completed top cylinder of cyclone
Figure 26. Mandy Wang preparing the sheet steel for the
fabrication of the collection box door.
Figure 28. Air inlet mid completion
Separation Device for Hazelnut Kernels and Shells Page 15 Figure 29. Cyclone cone, top cylinder and shell collection
box ready for assembly.
Figure 31. Caynen Klessig completing a component of the
air inlet
Figure 30. Kathleen Roush testing the hole punch to
prepare for the fabrication of flanges
Figure 32. Rebecca Smith preparing sheet steel for the
fabrication of an element of the air inlet
Separation Device for Hazelnut Kernels and Shells Page 16 Testing
Two tests were conducted during the separator
development process including: (1) A capacity check
on the vibratory feeder and (2) a test of the
prototyped zigzag aspirator design.
For the first test, we poured 22 lbm of the shell kernel
mixture into the hopper and turned the vibratory
feeder on. The entire mixture exited the end of the
vibratory plate in 57 seconds. Thus on the lowest
setting, the separator can deliver approximately 1,400
lbm of the mixture an hour. We then turned the
vibratory plate up to its highest setting, and the 22
lbm of mixture exited the vibratory plate in 7.5
seconds. Thus on the highest setting, the separator
can deliver approximately 10,500 lbs of mixture per
hour. Both settings meet and surpass our design
specification capacity of 500 lbs per hour.
For the second test, we collected a sample of hazelnut
kernels and shells and ran them through the separator
twice with the prototyped zigzag aspirator attached.
We collected the shells that were separated into the
collection box and spray painted the shells red. We
then remixed the painted shells back in with the
separated mixture and ran the mixture through the
separator again (figures 33 and 34). We were then
able to see the separation quality that our design
could produce. From this test, we concluded that our
aspirator does not perform at the level at which we
want it to. Thus we have started the process of
making design modifications to the aspirator column
to address the issues observed during testing.
Figure 34. Red shells being separated out in the
aspirator
Economics
A detailed list of all parts cost can be found in
Appendix E. The total material cost for our aspirator
was just slightly under our design spec of $2500.
Safety
To ensure safe food, adequate sanitation programs,
and worker safety, every part of this project was
designed and fabricated to a higher standard. This
higher standard is to prevent product contamination
and consumer health problems. This requires any
material coming into direct contact with kernels be
food grade and fabrication of parts be according to
standards set in Seiberling (1973).
WE designed and built out machine so that parts that
need to be food grade can quickly be fabricated out
of stainless steel. Note that we did not use stainless
in our current build as we wanted to make sure that
the system is performing adequately first.
Figure 33. Mixture of kernels and red shells after
separation
We specially designed our aspirator so that all air
used in the system would quickly and easily be
exhausted out of the building so that the level of airborne contaminates would not be increased by its use.
Separation Device for Hazelnut Kernels and Shells Page 17 As of this report we have not measured sound levels.
That said, the machine is surprisingly quiet so we
think we should not have a problem meeting this
requirement.
Finally, we took great care in overall design to ensure
that there were no real sharp corners, or major pinch
points.
Durability
A SOLIDWORKS stress analysis was completed on
the base plate of the frame because it supports all
vital components. Maximum loads were placed on
the base plate to simulate a full hopper, full kernel
collection barrel and a full shell collection barrel, as
well as all device component weights. The analysis
showed that the base plate would only deflect 0.58
mm in this maximum load case, and given the steels
yield strength, a factor of safety of 4.45 was achieved
at the weakest point of the base plate. This accounts
for any unexpected loads that could be placed on the
device. More details about this analysis can be found
in Appendix D.
Achievement of Objectives
We will not know the capacity, noise level and dust
level until the machine is fully fabricated and
operating with the optimal aspirator design.
However, we have met most of our design
specifications not dependent on operation. We have
designed for the eventual use of food-grade materials
where they are needed. There are no extruding or
rotating parts that could potentially hurt the operator.
The fan motor and the vibratory feed plate operate on
a standard outlet, and the air flow has an adjustable
valve to modify airflow.
All that said, our aspirator currently not performing
as expected. More fabrication and testing of aspirator
columns will occur in the future and we are quite sure
we can meet the 98% separation performance
requirement that we established.
References
1. American Hazelnut Company. (2014). The
Company. Retrieved from
http://www.americanhazelnut.co/thecompany.html
2. Corino, E. R., & Brodkey, R. S. (1969). A visual
investigation of the wall region in turbulent
flow. Journal of Fluid Mechanics, 37(01), 1-30.
3. Denfeld Packing Company (2014). MultiAspirator in Oregon
4. Emenegger, F., & Westfall, J. H. (1918). U.S.
Patent No. 1,279,308. Washington, DC: U.S.
Patent and Trademark Office.
5. FMC Corporation. [Joe DiSalvatore]. (2007, Nov
10). FMC Hopper Design- the correct way.
[Video file]. Retrieved from
https://www.youtube.com/watch?v=YnZnJ_u3u5
w
6. Fischbach, J., & Brasseur, K. (2012). Processing
American and Hybrid Hazelnuts: A Guide for
Hazelnut Growers in the Upper Midwest.
Retrieved from
http://www.midwesthazelnuts.org/assets/files/Pr
ocessing%20Guide_Jan%202012.pdf
7. Mizer, M. A. (1987). U.S. Patent No. 4,699,049.
Washington, DC: U.S. Patent and Trademark
Office.
8. Occupational Safety & Health Administration
[OSHA]. (2015). Regulations (Standards-29
CFR 1910.212). Retrieved from
https://www.osha.gov/pls/oshaweb/owadisp.sho
w_document?p_table=STANDARDS&p_id=983
6
9. Occupational Safety & Health Administration
[OSHA]. (2015). Regulations (Standards-29
CFR 1910.95). Retrieved from
https://www.osha.gov/pls/oshaweb/owadisp.sho
w_document?p_table=STANDARDS&p_id=973
5
10. Seiberling, D. A.(1973). "Design Principles and
Operating Practices Affecting Clean-In-Place
Procedures of Food Processing Equipment,"
Cleaning Stainless Steel, ASTM STP 538,
American Society for Testing and Materials,
1973, pp. 196-209.
11. OSHA & ACGIH. (2012, December 11).
Particulates Not Otherwise Regulated (Total
Dust). Retrieved from
https://www.osha.gov/dts/chemicalsampling/data
/CH_259640.html
12. Schmidt, Ronald H., and Daniel J. Erickson.
"Sanitary Design and Construction of Food
Equipment." FSHN0409, University of FloridaIFAS Extension (2009).
13. World Health Organization (WHO). (1999).
Hazard Prevention and Control in the Work
Environment: Airborne dust. Occupational
Health. Retrieved from
http://www.who.int/occupational_health/publicat
ions/airdust/en/
Separation Device for Hazelnut Kernels and Shells Page 18 Appendix A – Fan Measurements and Testing
Careful consideration was taken to ensure the blower
fan could produce the required air velocities needed
to pick up the shells and dust given the static pressure
drops across each component. In order to size the
components appropriately, we set up a few tests to
acquire a fan performance curve and to develop a
system curve in the Biological Systems Engineering
Lab as shown in Figure A1.
Figure A2. Pitot tube and air flow meter used for measuring
air flow.
Table A1: 1 inch of outlet covered
Figure A1. Preparing the fan for measurements
The first test was performed on our single phase 2 hp
blower motor. Being single phase, the motor runs at a
constant rpm, in this case 3450 rpm. Using a pitot
tube (Figure A2), we read the static pressure and the
velocity at the entrance and exit of the fan. We ran
eight runs, with different air inlet restrictions to see
how the static pressure drop and volumetric flow rate
changed with different resistance. Each run took
measurements according to the log-Tchebycheff
method (Figure A3) with 6 points spaced across the
cross-section near the fan outlet. Using the logTchebycheff method ensured that we recorded an
accurate measurement of the actual volumetric flow
rather than one point. The results from one of these
tests is shown in Table A1.
The change in volumetric flow rate was computed
with the equation:
Volumetric Flow Rate = Velocity x Cross-sectional
Area
Pitot Tube Depth, in
0
0.266
1.08
2.57
5.43
7.74
Air Velocity, fpm
1330
2020
2050
2230
2450
1648
With the data from the first test, we plotted the static
pressure drop against the change in volumetric flow
rate to develop the fan performance curve. The fan
will always operate at the intersection of the static
pressure drop and volumetric flow. Once we had the
fan performance curve, we needed to test various
components to estimate the static pressure drop in our
proposed system. We measured the pressure drop
across different elements in the new system.
Volumetric flow rate and static pressure drop will
always act predictably and repeatedly across a
component. This is called a system line. Figure A5
shows the fan curve(blue) and the system
curve(orange), the machine operation point is the
intersection of these two lines.
Separation Device for Hazelnut Kernels and Shells Page 19 Using the design's system line and desired velocity
within the cyclone and velocity to separate the shell
and kernel mixture, we could size different parts of
our design to give a constant volumetric flow rate. A
high velocity throughout the cyclone is ideal, but
more specific velocities are needed at the aspirator.
We estimated the velocity at the aspirator to be 450
fpm in order to make sure we could maximize
separation efficiency and not have any shells fall
through the aspirator. We had to ensure that the
velocity never dropped enough to allow the shells to
stop anywhere in the design. To achieve this, we
altered the flow rate equation to:
Cross-sectional Area = Volumetric Flow Rate /
Velocity
Figure A3. log-Tchebycheff method diagram for pitot tube
placement during air velocity measurement
http://www.tsi.com/uploadedFiles/_Site_Root/Products/Literature/H
andbooks/IAQ_Handbook_2011_US_2980187-web.pdf
Figure A5. System Performance Curve
Separation Device for Hazelnut Kernels and Shells Page 20 Appendix B – Cyclone Design
To properly size the cyclone, we used the operating
point obtained from the fan performance curve.
Measurement details and fan performance curves can
be found in Appendix A. We realized that optimal
shape and laminar air flow were the most important
factors in the design of a successful cyclone.
The air inlet of the cyclone in this design has several
qualities that help create laminar flow. The first
quality is the inlet angle. The inlet pipe was oriented
on the side and downward at approximately 14° from
horizontal. Entering tangent to the central outlet pipe
directs the flow around the center of the cyclone,
reducing the reliance on gravity to bring the particles
to the bottom and collection bin. The second quality
is the inlets rectangular shape. This creates a much
less turbulent entrance than a round inlet pipe that
does not match the cross-sectional rectangular shape
between the cylinder wall and outlet pipe. The third
quality aiding in laminar flow is the inlet path. The
inlet continues into the cylinder tangent to the outer
edge until the contact is made with the outlet pipe.
This is called a neutral vane and ensures that air flow
is not obstructed by hitting the outlet pipe upon
leaving the inlet.
The cyclone fabricated closely followed the design
instructions of Bill Pentz’s cyclone cutting layout,
which can be found on Bill’s website billpentz.com.
Using his cyclone sizing spread sheet, we were able
to make modifications to his design to fit our design
specifications. We decreased the cyclone cylinder
height and cyclone outlet pipe configuration to fit our
height restriction design specification. Figure B1
shows the main parts that were fabricated to create
the cyclone.
Separation Device for Hazelnut Kernels and Shells Page 21 Figure B1. Bill Pentz Cyclone Design
Separation Device for Hazelnut Kernels and Shells Page 22 Appendix C – Cyclone Simulations
SOLIDWORKS was used to simulate both low air
flow rate and high air flow rate at the outlet of our
cyclone design as seen in Figures B1 and B2,
respectively. This was done to test if our cyclone was
designed properly to separate the shells and dust from
the air.
The boundary conditions we tested were:
1.
200 cfm at air inlet perpendicular to surface,
atmosphere pressure at air outlet, covered bottom
(Figure B1).
2.
500 cfm at air inlet perpendicular to surface,
atmosphere pressure at air outlet, covered bottom
(Figure B2).
A trajectory flow view of the cyclone is shown to
illustrate the pressure results on the cyclone outlet.
The results look consistent and pressure gradually
drops. The results match that of a working cyclone.
Figure B2. Cyclone airflow simulation at 500 cfm
Figure B1. Cyclone airflow simulation at 200 cfm
Separation Device for Hazelnut Kernels and Shells Page 23 Appendix D – Structural Analysis
A structural analysis simulation was performed on
the base plate, including the angle iron supports
attached to the bottom, using SolidWorks Simulation.
We applied an extreme load combination
simultaneously to the plate and measured von Mises
stress, deflection, and factor or safety. 750 pounds
were applied to the hopper end to account for the
weight of the hopper and nut/shell mixture
transferred from the angle iron beneath the hopper.
350 pounds was placed where the kernel collection
barrel would be placed beneath the aspirator column.
Finally, 500 pounds were placed on the plate where
the shell cyclone collection box is supported,
accounting for the weight of the shells, dust, cyclone,
reducer, and support components.
The results showed the bottom plate strength
exceeded requirements to support our extreme load
case of 1600 pounds total with a minimum factor of
safety of 4.4516. It was also proven to be very rigid,
deflecting under the load by only 5.79 millimeters
(0.039 inches).
Figure D1. Exaggerated expected deformation and factor of safety
Separation Device for Hazelnut Kernels and Shells Page 24 Figure D2. Combination of loads shown on base plate
Figure D3. Displacement of base plate
Separation Device for Hazelnut Kernels and Shells Page 25 Appendix E – Material Costs
Separation Device for Hazelnut Kernels and Shells Page 26 Separation Device for Hazelnut Kernels and Shells Page 27 Appendix F – Process Flow
The hazelnut kernel and shell separation process
begins with the addition of the shell and kernel
mixture to the in-feed hopper (1). The mixture drops
onto the vibratory feeder plate (2). The vibrating
plate feeds the mixture into the aspirator (3). At this
point, the separated shells are drawn up into the air
inlet system (4) and the kernels fall to the bottom of
Number
1
2
3
4
5
6
7
8
the aspirator. The shells then enter the cyclone
separator (5) where they are separated from the air
and drop into a HDPW container located in the
collection box (6). Any shells or fine dust particles
that happen to enter the blower fan (7) instead of
being separated out of the air, leave the system
through the exhaust tube (8)
Component
Hopper
Vibratory Plate
Aspirator Column
Air Inlet
Cyclone
Collection Box
Fan
Exhaust Tube