Design and Analysis of a Washer for Reusable Bottles
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The FDA and Public health food code was adhered to
obtain a standard for the cleanliness of the bottle. It
was concluded that in order to obtain a clean and
sanitized product, the bottle would have to be run
through the bottle washer and then completely
submerged in a hot water tank at a temperature of 77o
C (171o F) or above.
At the first attempt of design a mechanism consisting
of an inner washer rotating about its axis was created,
driven by thrust forces developed at the exit of the
fluid, with an outer washer oscillating on its own axis.
The motion of the outer washer was intended to be
driven from the rotating motion of the inner washer,
connected by a cam-follower-crank system. A base
connection, which contained the inlet port for the
mechanism, was responsible in separating the flow
into each washer.
Manufacturing this prototype proved to be immensely
expensive, which then forced the manufacturing of a
½ scale model; which then wasn’t helpful in being
able to wash a bottle. The material of production,
(ABS plastic), did not meet the FDA standards for
ware washers. After this design was discarded, a new
design was created in its place.
Aluminum was used chosen for the material. The use
of aluminum material met the FDA code for the
material properties used for standard washing
equipment. A new design was made with just an inner
washer, outer washer, and a base plate that had
connections to the hoses connected to the hot water
outlet. The mechanical system was eliminated, as it
proved to be too complex and unnecessary for the
design. Materials were sourced from the local
aluminum supply store, with a re-dimensioning done
of the entire assembly done after obtaining the
materials of standard dimensions. After obtaining the
materials, the holes on the washer were drilled,
machined to cut away excess materials, and the outer
washer was welded off to create a seal on the top.
Pipefitting adapters were drilled on the bottom of the
plate to connect the hoses to the inner and outer
washers, while a brass cap was put on the top of the
inner washer to seal off the top. A hole at 30 degrees
was drilled on the inner washer for the water to reach
the inner edges of the bottle.
Calculations were made to obtain proper flow through
the mechanism. The total outlet area of each washer
was slightly smaller than the inlet area so as to create
some acceleration though the exit orifices, but not too
small to reduce stagnation pressure in sections of the
mechanism. Drainage holes were created to prevent
flooding of the assembly during washing. The
drainage holes were calculated by assuming a higher
value of the flow rate of drainage exit compared to
the total flow rate from all the orifices. The diameter
of each drainage holes was set at 0.75”, which worked
perfectly in draining the used water in the mechanism.
In testing the prototype, flow rates were measured and
used in calculating the error of the mechanism. As for
potential improvements to the prototype, it was
observed that a rise in length and increase in angle of
the top layer exit orifices for the outer washer could
be made to get a better outside clean for the bottle.
The design being an open-ended prototype could also
be redesigned for cleaning cups, and other hollow
plates and kitchen equipment. It could also be
redesigned, with the mechanism connected together in
multiple rows, which would deem viable for washing
multiple bottles at the same time.
The design and prototype worked perfectly well,
while achieving all the set out goals. The cost of the
redesigned prototype made with aluminum was far
less than the cost of the previous design made out of
ABS material. In relation to the expenses of the
athletic department, the cost of manufacture and
purchase of this mechanism would be insignificant in
comparison to the daily cost the department incurs in
utilizing disposable bottles. This design also
eliminates the cause of plastic waste into the
environment, contributing to a more green University.
Lessons Learned:
A great deal was learned from this project. This
project got us familiar with the design process. The