User manual HANNA INSTRUMENTS HI 93703

[. . . ] The meter covers a 0-1000 FTU range in two scales: 0. 00 to 50. 00 FTU and 50 to 1000 FTU. The autoranging feature of the instrument sets the appropriate range for the measurement. Note: HI 93703 has been designed according to the ISO 7027 International Standard, consequently the turbidity measurement unit is the FTU (Formazine Turbidity Unit). FTU is identical to the other internationally recognized unit: NTU (Nephelometric Turbidity Unit). 3 HI 93703 is a portable turbidity meter with the mark, in compliance with the European directives, ensuring low emission values and accurate measurements in presence of electromagnetic fields. [. . . ] · Place the cuvet into the cell and check that the notch on the cap is positioned securely into the groove. · The mark on the cuvet cap should point towards the LCD. · Press the READ/ key and the LCD will display a blinking "SIP" (Sampling in Process). The turbidity value will appear after approximately 25 seconds. 9 · Even though HI93703 covers a very wide range of turbidity values, for very accurate measurements of samples exceeding 40 FTU *, Standard Methods require dilution. In such cases, the correct amount of HI 93703-0 or turbidity-free water to be added to the sample can be calculated as follows: Vos = 3000 / T where: Vos = volume of sample combined with HI obtain the final 100 mL. T = HI 93703 reading 40FTU*) (mL) to be 93703-0 to volume of (exceeding E. g. : HI 93703 reading = 200 FTU * 3000 / 200 = 15 mL (Vos) 15 mL (Vos)+85 mL (HI 93703-0) = 100 mL At this point, take a sample of this solution and measure turbidity. The correct turbidity value of the original sample will be: Tn x 100 mL / Vos = Ta where: Tn = new HI 93703 reading Ta = actual turbidity value of the original sample * 1 FTU = 1 NTU 10 HOW TO ENSURE ACCURATE MEASUREMENTS · Each time the cuvet is used, tighten the cap to the same degree. · Discard the sample soon after the reading is taken to avoid permanently clouding the glass. · All glassware used to contain the standards and the samples should be maintained clean, washed with HI 93703-50 cleaning solution and rinsed with HI 93703-0 or turbidity-free water. · Collect the samples in clean glass or plastic bottles, fit stoppers and perform the analysis quickly. If unavoidable, store the sample in a cool, dark place, but not for longer than 24 hours (the sample needs to be kept at room temperature prior to the analysis). · To obtain a representative sample, gently, but thoroughly, mix it before samples are taken. Do not shake (to prevent air bubbles) and do not let the sample settle. · It is recommended to monthly calibrate the meter with the supplied HI 93703-10 @10 FTU* standard or more frequently for greatest accuracy. · Before inserting vials into the instrument, wipe them with HI 93703-70 soft, lintfree tissue. Handle vials so that no fingerprints can get on the areas where light passes (approximately 2 cm/1 inch from the bottom of the vial). If you experience any problems in taking measurements, please contact your dealer or the nearest Hanna Instruments Customer Service Department. 11 * 1 FTU = 1 NTU SOURCES OF INTERFERENCE · Presence of floating debris and coarse sediments which settle out rapidly will give false readings. · The infrared light source used for HI 93703 turbidity meter, according to ISO 7027 International Standard, can effectively minimize errors due to colored dissolved substances. This effect, named "true color", is a common interference for most commercially available instruments operating in the range of visible light. · Air bubbles and the effect of vibrations that disturb the surface of the sample will give false results. · Dirty glassware could also affect readings along with scratched or edged vials. 12 CALIBRATION A monthly calibration is recommended. To check the date of last calibration, simply hold the DATE/ key down for few seconds. A more frequent check of the instrument is suggested by using the supplied standard solution. CALIBRATION PROCEDURE · Turn the meter on and wait for the display to show "----". [. . . ] If the repair is not covered by the warranty, you will be notified of the charges. When shipping any instrument, make sure it is properly packaged for complete protection. To validate your warranty, fill out and return the enclosed warranty card within 14 days from the date of purchase. Reproduction in whole or in part is prohibited without the written consent of the copyright owner. [. . . ]