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To change the wiper pad:
1
Make sure you have the 1.5 mm hex key and a new pad for the wiper. Loosen
the small set screw on the wiper arm.
2
Remove the wiper pad from the wiper arm and replace the pad.
3
Place a new wiper arm on the motor shaft so that the set screw faces the flat
spot on the motor shaft.
4
Gently press the wiper pad against the face of the probe until the pad is
compressed to roughly three quarters of its original thickness. It is important
that the wiper arm does not make contact with the probe face – only the pad
should be in contact. A gap of 0.5 mm between the wiper arm and the probe
face is typical when a new pad has been installed. Another way of setting the
pad gap is to place the pad such that you can slide a small piece of paper under
the pad, but snug enough that the pad will hold the paper.
5
Tighten the set screw.
Do not over-tighten the set screw on the little rotating arm that holds the wiper pad; that will strip the threads,
and that will cause cursing once you realize what you did. And don’t rotate the wiper arm manually; that will
strip the gears and stick you with a big, hard-to-explain repair bill.
Your turbidity sensor may be equipped at the factory with an extended brush arm. For best results, change the brush
frequently by pulling the old brush out of the brush arm body, and sliding a fresh brush into the brush slot as shown
below.
Use the first Allen wrench from your wiper kit to remove the standard turbidity sensor wiper. Use the other Allen wrench
to install the brush arm. Notice that the Allen set screw seats on the flat side of the wiper motor shaft.
The new Scuba software version adds several turbidity features for the hard-core turbidity people. Please see 3.6.
4.14 Fluorometers
Eijkelkamp’s chlorophyll, rhodamine, blue-green algae, CDOM, fluoroscein,
and crude oil sensors are Turner designs fluorometric sensors, with each
tuned to the slightly different wavelengths.
Fluorescence occurs when a molecule absorbs light at one wavelength and
then emits that energy at a different wavelength. More molecules of
analyte produce a higher level of that different-wavelength light.
Fluorometric sensors emit light at a certain wavelength, and look for a
very specific, different wavelength in return. The magnitude of the return light is relatable to the amount of analyte
present.
Note that there are two types of blue-green algae sensors – fresh-water and marine.
Note that CDOM, or Colored Dissolved Organic Matter, is also known as fDOM (fluorescent Dissolved Organic Matter),
dissolved organic matter, yellow substance, and Gelbstoff.
Note that there are many different types of crude oil, and each has a relatively unique fluorescence response.
We use Turner designs fluorometers because Turner is recognized as the world’s leading manufacturer of
miniature fluorescence sensors.
