OBS501 Smart Turbidity Meter with ClearSensor
®
Technology
26
TABLE 8-5. Change in TU value resulting from one hour of
evaporation of SDVB standard
Calibration-cup Size
φ
mm (
φ
in)
250 TU
500 TU
2000 TU
4000 TU
100 (4)
+0.26
+0.52
+2.10
+4.20
150 (6)
+0.60
+1.20
+4.80
+9.70
Materials and equipment used in the procedure:
OBS501 with cable,
datalogger, large black polyethylene plastic tub (0.5 M I.D. X 0.25 M deep) for
measuring the clear-water points, and 100-mm and 200-mm black PE
(polyethylene) calibration cups.
Procedure
1.
Swab sensor with an alcohol-soaked towel to sterilize it. Position the OBS
sensor in a large, black tub of fresh tap water as shown in FIGURE
and
record a 10 s average of the low-range output. Record the average output
on the calibration log sheet.
FIGURE 8-3. Position of OBS501 in clean tap water in big black tub
2.
Pour the first SDVB standard into the appropriately sized cup (see TABLE
).
3.
Position the OBS sensor in the cup as shown in FIGURE
, and record
10 s averages of the low- and high-range outputs. Record the average
outputs on the calibration log sheet.
4.
Pour the standard back into its container.
