UWE Bristol Engineering showcase 2015

Loh Zhe Han
MENG Mechanical Engineering
Project Supervisor
Dr Tushar Dhavale
Seeds Material Handling
Background
Seed tapes are a pre-sown product that is made
of two layers of very thin paper attached together,
holding rows of seeds in between.
The method of seed transportation needs to be
able to evenly distribute seeds in neat rows, and
for the seeds to be roughly equidistant from each
other within the same row.
Seeds come in all shapes and sizes, often
demonstrate poor flow characteristics, and are
difficult to handle.
Vibrating Feeder Design
An adaptation of the linear vibratory feeder was
designed for the investigation. One speaker would
be used to drive the platform along the x-axis, and
two speakers would drive the platform along the
y-axis. The speakers are essentially actuators or
pistons that rapidly move the platform in their
respective directions. By controlling the phase
shift, the direction of the platform’s movement
can be regulated.
Time (s)
Test Results
The speakers are connected to an amplifier, and
their amplitudes are controlled by the “Volume”
control.
Firstly, tests were performed to measure the phase
shift at which the seeds flowed the best. A good
indicator of the quality of feeding is the difference
in time for the first and last seeds to travel the
entirety of the platform. A small time difference
demonstrates good feeding characteristics
because it means the body of seeds is travelling
relatively uniformly. The most appropriate phase
shift was found to be 270 degrees, at which the
platform is making an anti-clockwise circular
motion.
80
70
60
50
40
30
20
10
Frequency (Vol. 4-10)
Project summary
The project is based on the method of
transportation and placement of seeds in the
manufacturing process of seed tapes.
An investigation was conducted to explore
alternative methods utilizing technologies
from different fields of engineering to
improve the process.
A transportation system is then designed and
analysed.
Project Objectives
The vibrating feeder was proposed as a
solution to the seed transportation problem.
The aims of the investigation are:
• Design and assemble a prototype vibrating
feeder
• Verify the performance capabilities of a
vibrating feeder to transport seeds
• Experimentally establish the relationship
between frequency, amplitude, and phase
shift for a uniform feed rate
Linear vibratory feeders, such as the one pictured
above, use an electromagnetic drive to excite the
system. Vibratory feeders are used in food
engineering to transport bulk material that often
do not flow well. It is also used in other industries
to transport ores, coal, aggregate, sand, powders,
etc.
Vibrating feeders employ pulsating current to
operate. When this current passes through, the
armature is pulled, and the transmitted force
vibrates the tray. Magnetic attraction between
the electromagnet and the armature occurs when
current is allowed to flow, at which the trough
and vibrator unit are then attracted to each other.
The power input to the speakers control the
amplitudes of the vibrations. The speakers’ setup
is better for an experimental system and proof-ofconcept,
as it allows quick tweaking and
adjustments. It also allows the platform to be have
different directions of motion. The
electromagnetic drive is only capable of motions in
one dimension, whereas the speakers can move
the platform in oval and circular paths as well.
0
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Frequency (Hz)
Vol. 4 (First seed) Vol. 4 (overall) Vol. 5 (first seed) Vol. 5 (overall)
Vol. 6 (first seed) Vol. 6 (overall) Vol. 7 (first seed) Vol. 7 (overall)
Vol. 8 (first seed) Vol.8 (overall) Vol. 9 (first seed) Vol. 9 (overall)
Vol. 10 (first seed) Vol. 10 (overall)
The test to determine the best frequency for the
platform to vibrate at was performed at a range of
“volumes”, to observe the performance of
different frequencies at a range of amplitudes of
the platform’s motion. From observances, the
platform fed the seeds most uniformly at 19 Hz,
“Volume” 5, with the lowest time difference
percentage of 37.8% (the average ∆T% is 65.7%).
The tests were first performed with basil seeds.
Sweet pepper seeds and giant sunflower seeds
were also tested on later, at the found optimal
settings. They also flowed well.
Project Conclusion
A prototype that utilises two directions of
excitation in the vibrating system was
designed. A variety of seeds were used as test
samples, and the system successfully
transported each type of seed.
Experimentation showed that a low
frequency, high deflection vibration system
was the most effective system to transport
seeds in a controlled manner.
The vibrating feeder was a successful proofof-concept,
and could be considered for
implementation in industry.