Electro-Chemical Devices (ECD) T80 - Manual (Page 61)

8.3.9 TRITON TR6 T URBIDITY
The TR6 turbidity sensors don’t require periodic service except in coating applications. Quarterly checks should
be performed to assure the accuracy of the measurement.
The TR6 response can become sluggish due to coating from materials in the process solution. Periodic cleaning
will minimize drift and maintain the sensors response.
CLEANING
The most important maintenance item is keeping the optically clear epoxy window clean. The TR6 turbidity
sensors are fairly robust and can be cleaned with alcohols, detergents or dilute acids to remove coatings caused
by greases, oils or films. Do not use solvents such as MEK, Toluene, Acetone, or trichloroethylene on TR6
sensors. A soft tooth brush or paper towel should be used to remove soft coatings. A Scotch Brite scouring pad
works well for most types of stubborn window fouling. First wet the pad and then place it on a counter with a
plastic-laminate top so that the side of the pad is aligned with the edge of the counter. Work the window of the
TR6 sensor back and forth on the pad until it is clean while removing as little epoxy as possible. If encrusting
organisms such as barnacles or tube worms have attached to the sensor, it will have to be gently scraped with a
flexible knife blade prior to using the pad.
POLISHING
Some applications will result in pitting of the sensor face. Pits can be removed with abrasive cloth. Polish the
sensor window as follows:
1) Tape a strip of 400 grit wet-or-dry abrasive cloth to the edge of a counter.
2) Add a few drops of water to the abrasive and work the sensor window in smooth one-way
strokes on the cloth using the counter edge as a guide.
3) Continue until the sensor is shiny and pit free.
It is important to remove as little epoxy as possible.
8.3.10 C ONDUCTIVITY AND R ESISTIVITY SENSORS
Cleaning agents should be specific to the type of coating, detergents or alcohols for removing greases and oils,
acids for removing hard water scales and metallic deposits or spray washing with water and a soft brush for
flocculants and biofilms.
Resistivity sensors rarely need cleaning due to the nature of the measurement. If cleaning is necessary or the
sensor has been in service for greater than two years follow the instructions listed below.
Rinse the sensing end with alcohol, methanol, ethanol or isopropyl will work fine.
Soak for 5 minutes in a dilute nitric acid solution, a 3.5% solution is made by a 20:1 dilution of concentrated
Nitric Acid (5 ml HNO
3
in 100ml of water).
Then rinse thoroughly with tap water and soak in distilled water for 5-10 minutes.
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