5
4
As noted above, FTU is equal to the NTU. However, other known
measurements include: Jackson Turbidity Unit or JTU (based on the
old method of Jackson's candle), and Silica Unit in mg/L of SiO
2
.
See the conversion table below for these units:
JTU
FTU/NTU
SiO
2
(mg / L)
JTU
1
19
2.5
FTU/NTU
0.053
1
0.13
SiO
2
(mg / L)
0.4
7.5
1
SPECIFICATIONS
Range
0.00 to 50.00 FTU*
50 to 1000 FTU*
Resolution
0.01 / 1 FTU*
Accuracy (@ 20°C/68°F)
±0.5 FTU*
±5% of reading (whichever greater)
Calibration
3 points (0, 10 and 500 FTU*)
Light Source
High-emission infrared LED
Light Source Life
Life of the instrument
Light Detector
Silicon photocell
Power Supply
12 Vdc power adapter (included)
Environment
0 to 50
°
C (32 to 122
°
F);
RH max 95% non-condensing
Dimensions
230 x 170 x 70 mm
(9.1 x 6.7 x 2.7")
Weight
600 g (1.3 lb.)
* 1 FTU = 1 NTU
* 1 FTU = 1 NTU
LP2000-11
has been designed to perform measurements according
to the ISO 7027 International Standards.
The instrument works by passing a beam of infrared light through a
vial containing the sample to be measured.
The light source is a High Emission Infrared LED with a wavelength
peaking at 890 nm, which reduces interferences caused by colored
samples to a minimum.
A sensor, positioned at 90° with respect to the direction of light,
detects the amount of light scattered by the undissolved particles
present in the sample. The microprocessor converts such readings into
FTU values.
IR LED
EMITTED LIGHT (890 nm)
CUVET
LIGHT
DETECTOR
90° SCATTERED
LIGHT
PRINCIPLE OF OPERATION
In addition,
LP2000-11
automatically stores the last calibration
date, that may be retrieved by a single key touch.
10 FTU* was chosen as the standard calibration point because its
value best fits the water turbidity measurements in a wide range of
applications, from drinking water to wastewater treatment.
Hanna uses the primary standard AMCO-AEPA-1 to avoid all formazine-
related problems. In fact formazine is a toxic, unstable substance, which
requires particular care. Its standards have to be prepared only a few
minutes before performing the calibration, and cannot be reused because
of their short life.
Hanna standards are extremely stable, can be reused, and last up to six
months, if free from contaminations.
LP2000-11
can be used with both standards.
