The HI98703 is a high accuracy (±2% of reading plus 0.02 NTU) Turbidity Portable Meter. The meter is supplied complete with AMCO-AEPA-1 primary turbidity standards used for calibration and performance verification. The HI98703 meets and exceeds the requirements of EPA Method 180.1 and Standard Methods for the Examination of Water and Wastewater 2130 B for turbidity measurements.
The HI98703 Precision Turbidity Portable Meter is specially designed for water quality measurements, providing reliable and accurate readings, especially in the low turbidity range. The instrument is based on a state-of-the-art optical system which guarantees accurate results, assures long term stability, and minimizes stray light and color interferences. Periodic calibration with the supplied standards compensates for any variations in intensity of the tungsten lamp. The 25 mm round cuvettes composed of special optical glass guarantee the repeatability of turbidity measurements.
Turbidity is one of the most important parameters used to determine the quality of drinking water. Once considered as a mostly aesthetic characteristic of drinking water, significant evidence exists that controlling turbidity is a competent safeguard against pathogens. In natural water, turbidity measurements are taken to gauge general water quality and its compatibility in applications involving aquatic organisms. The monitoring and treatment or wastewater was once solely based on the control of turbidity. Currently, the measurement of turbidity at the end of the wastewater treatment process is necessary to verify that the values are within regulatory standards.
Turbidity of water is an optical property that causes light to be scattered and absorbed, rather than transmitted. The scattering of light that passes through a liquid is primarily caused by the suspended solids present. The higher the turbidity, the greater the amount of scattered light. Even a very pure liquid will scatter light to a certain degree, as no solution will have zero turbidity.
Drinking water treatment plants that obtain water from surface water are required by the EPA to monitor and report the turbidity. Surface water sources include lakes and rivers. The requirements of the nephelometer and reporting measurements according to EPA Method 180.1 are:
|NTU reading||Rounded to nearest|
|0.0 - 1.0||0.05|
|1 - 10||0.1|
|10 - 40||1|
|40 - 100||5|
|100 - 40||10|
|400 - 1000||50|
The HI98703 meets and exceeds the meter criteria specied by the EPA Method 180.1 and Standard Methods for the Examination of Water and Wastewater 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, such as wavelength of the incident light, particle size and shape, refractive index, and color. The optical system of the HI98703 includes a tungsten filament lamp, a scattered light detector (90°) and a transmitted light detector (180°).
In the ratio turbidimeter range, the microprocessor of the instrument calculates the NTU value from the signals that reach the two detectors by using an effective algorithm that corrects and compensates for interferences of color. The optical system and measuring technique also compensate for fluctuations in lamp intensity, minimizing the need for frequent calibration.
In the non-ratio turbidimeter range, the NTU value is calculated from the signal on the scattered light detector (90°). This method offers a high linearity on the low range but is more sensitive to lamp intensity fluctuations. The lower detection limit of a turbidimeter is determined by stray light that is detected by the sensors but not caused by light scattering from suspended particles. The optical system of the HI98703 is designed to have very low stray light, providing highly accurate results for low turbidity samples.
The HI98703-11 AMCO AEPA-1 standards ensure that measurements are traceable to a primary reference materials. These standards are used for calibration and performance verification of the turbidity meter.
|Range||0.00 to 9.99; 10.0 to 99.9; 100 to 1000 NTU|
|Resolution||0.01; 0.1; 1 NTU|
|Accuracy||±2% of reading plus 0.02 NTU|
|Repeatability||±1% of reading or 0.02 NTU, whichever is greater|
|Stray Light||< 0.02 NTU|
|Light Detector||silicon photocell|
|Method||ratio nephelometric method (90° & 180°)|
|Measuring Mode||normal, average, continuous|
|Turbidity Standards||< 0.1, 15, 100, and 750 NTU|
|Calibration||two, three, or four-point calibration|
|Light Source||tungsten filament lamp / greater than 100,000 readings|
|Display||60 x 90 mm backlit LCD|
|Log Memory||200 records|
|Connectivity||USB or RS232|
|Environment||0 to 50°C (32 to 122°F), RH max 95% non-condensing|
|Power Supply||1.5V AA alkaline batteries (4) or AC adapter; auto-off after 15 minutes of non-use|
|Dimensions||224 x 87 x 77 mm (8.8 x 3.4 x 3.0”)|
|Weight||512 g (18 oz.)|
|Ordering Information||HI98703 is supplied with sample cuvettes and caps (5), HI98703-11 calibration cuvettes, silicone oil, cuvette wiping cloth, batteries, AC adapter, instruction manual, and rugged carrying case.|