Portable turbidity meters for accurate turbidity measurements in the laboratory or field studies.
With the new portable turbidity meters Turb 430 T and Turb 430 IR, the user now has the choice to perform nephelometric measurements at 90° scattered light according to the application and standard required. The Turb 430 IR portable turbidity meter meets the DIN 27027/ISO7027 requirements, the Turb 430 T those of US EPA 180.1. The portable turbidity meter's measuring range is from 0 to 1100 NTU/FNU and is identified automatically. Accurate measurements by the portable turbidity meters in the lower range, e.g. in drinking water are no problem!
The Turb 430 Portable Turbidity Meters have menu driven 3 point calibration and all measurement functions are easy for even the most inexperienced operator to perform accurate and precise measurements. The calibration is via an AMCO® standards set (0.02-10-1000 NTU). The quality of the measurement results is supported by adjustable calibration intervals with documentation. The Turb 430 Portable Turbidity Meters are not only a field measuring instruments (especially with the practical field case), but also a "small lab instrument" for applications up to 1100 NTU/FNU and with optimum data management. Applications for the portable turbidity meters include all water testing applications, such as drinking water, process control, and the wine making industry.
|Typical turbidity meter values for various liquids|
|Drinking water||0.02 to 0.5|
|Spring water||0.05 to 10|
|Wastewater (untreated)||70 to 2000|
|White water (paper industry)||60 to 800|
Why use a Portable Turbidity Meter?
Turbidity measurements are of extreme importance in quality monitoring in water, wastewater, beverage production, electroplating and petrochemical applications. Light passing through liquid which contains undissolved solids, such as algae, mud, microbes and other insoluble particles, is both absorbed and scattered. Turbidity increases with the amount of undissolved solids present in the sample. However, the shape, size and composition of the particles also influence the degree of turbidity. Turbidity has been determined by simply measuring light passing through the sample. Measuring the scattered light at an angle of 90° has proved to be a more accurate method particularly at lower measuring ranges. Portable turbidity meters that use this method are also referred to as nephelometers.
Portable turbidity meters or nephelometers instruments differ by the light source they utilize. Infrared (IR-LED) portable turbidity meters with a wavelength of 860 nm are required for methods: ISO 7027/DIN EN 27027 (EN ISO 7027). Standard methods specifies the use of portable turbidity meters that use white light by a tungsten wide-band lamp for water and wastewater analysis.
Which light source - infrared (IR) or white light (tungsten) do you need for your portable turbidity meter?
An infrared light source minimizes or even eliminates the influence of coloration in a solution, because there is practically no absorption at a wavelength of 860 nm. The detection sensitivity for small particles, on the other hand, is somewhat lower at this wavelength because of the generally lower light scattering of small particles. White light has a higher sensitivity for small particles, however with this source the inherent coloration of the solution has a stronger disturbing effect on the measurement. The IR measurement source is required for portable turbidity meters to meet DIN ISO standards, while turbidity meters using a tungsten white light measuring source are required by the US EPA.
Nephelometric or transmittance measuring?
The nephelometric method of measuring with 90° scattered light is advantageous for the lower turbidity range. In contrast, the transmittance method is better suited for medium to high turbidities, where there are stronger light scattering and shadowing effects among the larger-sized particles. In this case, the diminution of light intensity gives a more accurate result than a 90° scattered light turbidity meter measurement. Laboratory turbidity meter instruments for higher turbidity ranges therefore offer significantly more measuring options.
Please note: As floating and moving particles are measured by the portable turbidity meters, slight measurement deviations are possible. In order for the portable turbidty meters to achieve results which are as representative as possible, attention should be paid to the following: