Hanna Instruments HI 83414 User Manual
Page 6
6
ABBREVIATIONS
NTU
Nephelometric Turbidity Units
JTU
Jackson Turbidity Units
FTU
Formazin Turbidity Units
USEPA US Environmental Protection Agency
LCD
Liquid Crystal Display
RTC
Real Time Clock
RH
Relative Humidity
ID
Identification
EBC
European Brewery Convention
TURBIDIMETER
Turbidity is the optical property that causes light to be scattered and absorbed, rather than transmitted.
The scattering of the light that passes through a liquid is primarily caused by the suspended solids.
The higher the turbidity, the greater the amount of scattered light. Because even the molecules in a
very pure fluid scatter light to a certain degree, no solution will have zero turbidity.
The
USEPA Method 180.1 specifies the key parameters for the optical system to measure turbidity
for drinking, saline and surface water, in a 0 to 40 NTU range, using the nephelometric method.
The
HI 83414 instrument is designed to meet or exceed the criteria specified by the USEPA Method
180.1 and Standard Method 2130 B.
The light beam that passes through the sample is scattered in all directions. The intensity and pattern
of the scattered light is affected by many variables like wavelenght of the incident light, particle size
and shape, refractive index and color.
The optical system includes a tungsten filament lamp, a scattered light detector (90
0
) and a
transmitted light detector (180
0
).
PRINCIPLE OF OPERATION