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5. Other measurement techniques
5.1 Ultrasound
The probe is immersed in the medium to be measured. The measuring probe consists of a piezoelectric crystal that acts alternately as transmitter and receiver. The ultrasonic pulse train is reflected (backscattered) by particles in the flowing liquid, and the returned waves are transformed into an electrical signal.
To enhance sensitivity, the system can be fitted with an acoustic lens to focus the ultrasound beam.
Measurement frequencies are available from 5 MHz to 15 MHz. Measurements can be taken at pressures of up to 20 bar. Units can be programmed in ppm, mg/L, %, etc.
Measurement is not affected by sample color or dirt, as the principle is self-cleaning.
Its measurement...
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Other measurement techniques
Regulations and standards
Bibliography
References
Glossary
Turbidity: the reduction in transparency of a liquid due to the presence of undissolved matter (NF EN ISO 7027 standard).
The definitions below are taken from FD ISO GUIDE 30.
Reference material (RM): material or substance for which one or more property values are sufficiently homogeneous and well defined to enable it to...
Regulations
Ministerial Order of February 2, 1998, published in the Journal Officiel of March 3, 1998
* Section III – Surface water pollution
Article 31
For receiving waters to which the provisions of Decree no. 91-1283 of December 19, 1991 apply, the effects of discharge must comply with the following provisions: no increase of more than 30% in suspended solids.
...
Standardization
- Water quality – Turbidity determination. - NF EN ISO 7027 - (mars 2000)
- Qualité de l'eau. Échantillonnage. Partie 1 : lignes directrices pour la conception des programmes et des techniques d'échantillonnage. - NF EN ISO 5667-1 - 2007
- Qualité de l'eau. Échantillonnage. Partie 3 : lignes directrices pour la conservation et la manipulation des échantillons d'eau. - NF EN ISO 5667-3 - 2004
- Qualité de l'eau....
Manufacturers and distributors
Table 1 lists the main equipment manufacturers and their distributors.
Organizations
Association of Measurement, Control and Automation Equipment Operators (Exera) http://www.exera.com/
ISA Instrumentation, Systems and Automation Society http://www.isa.org
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