Simple Physical Testing
Objective
Obtain a better understanding
of the operation of your water treatment device.
Equipment / Supplies
Your water treatment device, water treatment device
manual, ruler, calipers, balance, stop watch, beakers.
Method
- Read the water treatment device manual,
figure out how the water treatment device works (e.g., what path does the water take,
are their check valves?, how is the water treated,...),
- Measure and draw it's parts by
hand, start creating AutoCAD or Solid Works drawings (see drawing handout).
Measure the stroke length or squeeze length, if appropriate.
- Identify manufacturer' claims/patents,
- Identify specifications (e.g.,
manufacturer's claimed treatment device cartridge capacity, flow rate, size
of particles
filtered, microbe removal percents, water treatment device "level" (e.g.,
1 or 2, is it a purifier
or not...),
- Check out the manufacturer web
site,
- Identify the cost of the water
treatment device and its components,
- Measure the amount of water
that can be treated in one minute at a number of different stroke rates
(strokes/min).
Try to pump at a constant rate. Do this for 6 to 9 different stroke
rates, spanning from a low stroke rate that achieves about 10% of the manufacturer's
claimed flowrate to as high as you
can go. Measure the number of strokes (or squeezes) and volume of water
(Liters) treated
in a minute. Water bottles may not be able to go a full minute. Calculate
the stroke rate, stroke velocity (velocity of piston in cm/sec), and flowrate
(liters/min)
for
each test.
Plot stroke
rate
(strokes/min)
on the x-axis
versus
flowrate
(liters/min) on the y-axis. Based in this experience, what
do you think is an easily obtained flowrate? What
is the
maximum flowrate attainable?
Is the relationship between stroke rate and flowrate linear? Over the
entire range of stroke rates tested? When comparing the results of different
treatment
devices, does it matter if your water treatment device pumps on the
down and up stroke or
just
the
down
stroke? Do up and down strokes
take the same time? If not, measure the difference.
- For gravity treatment devices,
relate the change in elevation of the water in the bag to the flowrate.
...and anything else you can
think
of! This information should be recorded in your laboratory notebook, with
sources clearly identified.
Putting your water treatment device
away
Read the manual to see how to
store your water treatment device before the lab is over.
If your data are unacceptable, you
will be expected to repeat experiments outside of normal class time.