turbidity measurement
TRANSCRIPT
CONTENTS
• Basics about turbidity
• Measurement units
• measurement techniques
• Calibration
• Application
CLASSIFICATION OF DEVICES
3 Factors affecting design of device
• Light source
• Detection angle
• Number of detector
LIGHT SOURCES
Source Wavelength Application
Incandescent light 400-600nm Shorter wavelength for
short particles
LED 830-890 nm Not effected by color in
sample
LASER 660nm Sensitive to smaller
changes,
Most effective for
filtration
DETECTION ANGLES
90 degree Most commonly used,
180 degree High turbidity application
Backscatter detection
angle
High turbidity application
Multiple detection
angle
Colour compensation
Dual light source
detector
Correction for color absorption and optics fouling
SIGNAL ON 180
DEGREES DETECTOR
What are we measuring ?
Robert Lagrange Sli
de
12
Concentration
Intensity
SIGNAL ON 90
DEGREES DETECTOR
What are we measuring ?
Robert Lagrange Sli
de
13
Concentration
Intensity
CALIBRATION
Two point calibration
-Zero point calibration- distilled water
-Spanning the instrument
Primary standard –formazin