129
TROLL
9500
Operator’s Manual
0095110 rev. 007 01/09
Cleaning may be necessary if the optical windows of the sensor
become visibly contaminated by the gradual accumulation of foreign
material. Because the sensor is not removable, we recommend gentle
swabbing of the windows with a circular motion using plain water.
Solvents are not recommended, although an ammonia solution (e.g.,
grocery-store ammonia) may be used with good effect to remove
particularly stubborn materials.
A calibration check should be performed after cleaning, using calibra-
tion standards.
WIPER MAINTENANCE
The cotton wiper pad will require replacement periodically to maintain
its effectiveness in cleaning the turbidity sensor optics. The entire
head may be replaced, or just the pad. In either case, the wiper head
will need to be removed. A hex wrench is supplied for this purpose.
You do not need to remove the entire wiper; leave the wiper body
installed in port 3.
Replacement pads and wiper heads
are available from In-Situ Inc. or your
distributor.
Removing the Wiper Head
With the wiper parked over port 4, loosen
the set screw on the wiper head until you
can grasp the wiper head and gently pull
it out.
Replacing the Wiper Pad
1. Remove the wiper head as above. Remove and discard the used
pad.
2. Insert a new pad into the slots with the smooth side facing out, and
pull to eliminate slack. Excess material may be trimmed close to
the wiper head.
3. Position the head on the motor shaft with the pad facing down to-
WARDTHESENSORS4HEBUTTONATTHETOPOFTHESHAFTSHOULDBEmUSH
WITHTHEWIPERHEADSURFACE4IGHTENTHESETSCREWAGAINSTTHEmAT
of the motor shaft.
Be very careful not to move the wiper head
in a lateral direction by hand after tightening.
4. If convenient, connect in software, select the wiper, and click
Wipe
to ensure the wiper passes over the turbidity sensor optics prop-
erly.
Adjusting Wiper Pressure
If necessary, loosen the set screw on the wiper head and gently pull
the head up or press down lightly to ensure the pad just brushes the
optical windows when it passes over the turbidity sensor. Then re-
tighten the set screw.
Be very careful not to move the wiper head
in a lateral direction by hand when engaged with the motor shaft.
TIP:
The wiper head is at the best height when it just
brushes the optical windows of the turbidity sensor—too high
and it will not clean effectively; too low and it may not be able to spin.
If it is necessary to remove the entire wiper assembly, be
sure to use the sensor removal tool and grasp the body of
the wiper. Do not attempt to pull the wiper out by the head.
Wiper Replacement Parts
Catalog No.
Replacement wiper head ....................................................... 0044520
Wiper pad replacement kit ...................................................... 0044530
REFERENCES
ASTM method D1889-88(A)
Eaton, A.D., L.S. Clesceri, E.W. Rice, and A.E. Greenberg, eds.,
Standard Methods for the Examination of Water and Wastewater,
21st edition, Washington, D.C.: American Public Health Associa-
tion, American Water Works Association, and Water Environment
Federation, 2005. Section 2130, Turbidity.
EPA, Methods for Chemical Analysis of Water and Wastes,
EPA/600/4-79-020, revised March 1983. Method 180.1, Turbidity,
Nephelometric. Approved at 40 CFR Part 136.
EPA, Methods for the Determination of Inorganic Substances in
Environmental Samples, EPA/600/R-93-100, August 1993. Method
180.1, Determination of Turbidity by Nephelometry, Revision 2.0.
Approved at 40 CFR Part 141.
International Organization for Standardization (ISO), 1999. Water
Quality—Determination of Turbidity, Method 7027.
Nollet, Leo M. L., ed.
Handbook of Water Analysis.
Marcel Dekker
Inc., New York, 2000.
U.S. Geological Survey, Methods for Analysis of Inorganic Substances
in Water and Fluvial Sediments, U.S. Department of the Interior,
Techniques of Water-Resources Investigations of the U.S. Geologi-
cal Survey, I-3860-85.
SECTION 18: TURBIDITY
To remove the wiper head,
use the supplied hex wrench
to loosen the set screw