EUTECH INSTRUMENTS TN-100 (01) PDF Document

The following items are included in your EUTECH INSTRUMENTS TN-100 turbidimeter shipment:

WARNING: Extra care should be taken when unpacking, opening, and handling the calibration standards and sample vials. Surface scratches or finger smudges on the vial surface may cause measurement errors. Handle these items by their caps only.

The keypad has five keys with the following functions:

Four AAA-sized batteries are included in the packaging. Follow these steps to install them:

1. Use a Philips screwdriver to remove the two screws holding the battery cover.

2. Remove the battery cover.

3. Insert the batteries. Follow the diagram inside the cover for correct polarity.

4. Replace the battery cover onto its original position using the two screws removed earlier.

5. The meter is now ready to operate.

NOTE: Dispose used batteries in accordance with your local regulations.

We recommend that you use the following materials during calibration to achieve the accuracy stated in the manual:

• CAL 1: 800 NTU Calibration Standard

• CAL 2: 100 NTU Calibration Standard

• CAL 3: 20.0 NTU Calibration Standard

• CAL 4: 0.02 NTU Calibration Standard

It is important that the calibration standards are not violently shaken or agitated because air entrapment in the fluid introduces an error factor during calibration which subsequently will lead to an inaccurate measurement. Also, do not store in freezing temperatures which causes irreversible shrinkage of the standards’ particles thus resulting to inaccurate calibration and measurement.

Each standard vial should be used with the same standard value (0.02, 20.0, 100, or 800 NTU) for the greatest accuracy. Follow the steps below at each change of solution.

1. Ensure there are no scratches or marks on the glass vial. If there are marks that could affect the turbidity measurement, select another vial.

2. Slowly and gently invert the calibration standard plastic bottle five times but do not shake the bottle as air bubbles can affect the reading.

3. Rinse a clean vial with 3-4 mLs of the calibration standard that will be used in this vial. Invert the capped vial 5 times. Uncap and dispose of the rinsate.

4. Repeat the rinsing steps and dispose of the rinsate.

5. Fill the vial with the primary standard solution to the fill line and cap the vial.

6. Clean the exterior of the vial using a lint-free cloth to remove all traces of liquid, dirt or fingerprints. Remove stubborn smudges with alcohol or a non-abrasive glass cleaner, and silicone oil can be used to fill small external scratches on the vial.

7. Repeat Steps 1-6 to prepare the other three standard solutions.

These standard vials can be used to check the meter calibration by reading back the standard value daily and also be used for calibration when needed. When the standard reading of 20.0, 100, or 800 NTU drifts more than 10% of the standard’s NTU value, the solution should be replaced with another aliquot from the plastic bottle following the Preparing the Standard Vials steps. The 0.02 NTU standard read back value should be <0.1 NTU.

Follow this sequence to calibrate your EUTECH INSTRUMENTS TN-100:

1. Starting from Measurement Mode, press the CAL key. The screen will display “CAL” and flash about 5 times.

2. The meter will display “CAL 1” and “800 NTU”. Place the CAL 1 (800 NTU) standard into the sample well.

3. Press the READ/ENTER key. The screen will show “800 NTU” and flash for about 10 times while it measures.

4. The meter will automatically advance to “CAL 2” and display “100 NTU”. Place the CAL 2 (100 NTU) standard into the sample well.

5. Press the READ/ENTER key. The screen will show “100 NTU” and flash for about 10 times.

6. The meter will automatically advance to “CAL 3” and display “20.0 NTU”. Place the CAL 3 (20.0 NTU) standard into the sample well.

7. Press the READ/ENTER key. The screen will show “20.0 NTU” and flash for about 10 times.

8. The meter will automatically advance to “CAL 4” and display “0.02 NTU”. Place the CAL 4 (0.02 NTU) standard into the sample well.

9. Press the READ/ENTER key. The screen will show “0.02 NTU” and flash for about 10 times.

10. After the final calibration point, the display will show “STbY”, and the meter will return to Measurement Mode.

The EUTECH INSTRUMENTS TN-100 allows you to reset the meter back to the factory default calibration values. This feature is extremely useful when there are errors in calibration or when you have new calibration standards.

1. With the meter switched off, press and hold the ▲ key.

2. Switch on the meter using ON/OFF. Release the ▲ key when “URST” (User-Reset) appears in the display.

3. The display shows “URST” for about 2 seconds and then shows “No”.

4. Use the ▲ or ▼ key to select between “YES” or “No”.

• YES = To restore meter back to factory calibration values

• No = To retain last calibrated values

5. Press the READ/ENTER key to confirm your selection. The meter performs the reset if “YES” is selected.

6. The display flashes “–Rd–” about 10 times indicating that the meter goes to measurement mode.

Before switching on the EUTECH INSTRUMENTS TN-100, a sample vial MUST be placed in the sample well. You can use any of the calibration standards for this purpose.

When the ON/OFF key is pressed, the meter goes through the following power-up sequence:

1. The model number (T 100) is displayed.

2. The software revision number is displayed (e.g., RXX).

3. All LCD segments are displayed briefly.

4. The display flashes “–Rd–” about 10 times, indicating the meter is preparing for measurement mode.

5. The meter enters measurement mode and displays a reading. A reading is valid only if you have placed a vial into the sample well. Otherwise, the reading has no meaning or an error message “Err 8” appears.

1. Obtain a clean and dry sample vial.

2. Take care to handle the sample vial by the top.

3. Rinse the vial with approximately 10 ml of the sample water, capping the vial with the black screw cap and gently inverting it several times. Discard the used sample and repeat the rinsing procedure two more times.

4. Fill the rinsed vial with the remaining portion (approximately 10 ml) of the grab sample up to the mark indicated in the vial. Cap the vial with the supplied black screw cap.

5. Wipe the vial with the soft, lint-free cloth supplied. Ensure that the outside of the vial is dry, clean and free from smudges.

6. Apply a thin film of silicone oil (supplied) on the sample vial.

7. Wipe with a soft cloth to obtain an even distribution over the entire vial’s surface.

NOTES:

• The purpose of oiling the vial is to fill small scratches and to mask the imperfection in the glass.

• Do not apply large quantity of oil as this may collect dirt and dust.

8. The sample vial is now ready to be inserted into the sample well of the meter for measurement.

1. Place the EUTECH INSTRUMENTS TN-100 turbidimeter on a flat and level surface.

2. Place the prepared sample vial inside the sample well and align the vial’s index mark with the meter’s index mark.

3. Push the vial until it is fully snapped in.

4. Cover the vial with the light shield cap.

5. Turn on the meter by pressing the ON/OFF key.

6. After the power-up sequence, the meter goes to measurement mode and the display blinks “–Rd–“ for about 10 times.

7. The measured reading appears in the display.

8. If necessary, place the second sample vial into the sample well. Remember to align the vial’s mark with the meter’s index mark.

9. Press the READ/ENTER key. The display blinks “–Rd–” for several times and the measured reading appears.

10. Repeat steps 8 through 9 for all of your samples.

IMPORTANT: Place the meter on a flat and level surface. DO NOT hold it in your hands while operating the meter as it may lead to inaccurate readings.

1. Make sure the meter is sitting on a flat and level surface and is in measurement mode. The display shows the last measured value or “STbY” after exiting calibration mode.

2. Place sample vial in the sample well.

3. Cover the vial with the light shield cap.

4. Press the READ/ENTER key and release immediately (<0.3 seconds).

5. The display blinks “–Rd–” for about 10 times and then displays the measured value.

Continuous measurement is primarily used for indexing vials.

1. Make sure the meter is sitting on a flat and level surface and is in measurement mode. The display shows the last measured value or “STbY”.

2. Place the sample vial in the sample well.

3. Press the READ/ENTER key and hold it down.

4. The display is updated every 2 seconds. Wait for the reading to stabilize before rotating the sample vial for indexing purposes.

5. Once you release the READ/ENTER key, the meter automatically performs a single-shot measurement.

NOTE: The reading displayed during continuous measurement may not be the actual turbidity value. For an accurate measurement, use the single-shot measurement method.

The EUTECH INSTRUMENTS TN-100 routinely performs self-diagnostics and will automatically generate messages to provide you with specific diagnostic information. Refer to the table below for corrective actions.

* If an error message appears, take the appropriate corrective action and re-do the desired procedure. If the problem persists, contact Eutech Instruments or your dealer.

Proper measurement of turbidity requires a vial that is free of marks, smudges, scratches, and bacterial growth. Handle vials with absolute care to avoid contamination or damage.

Cleaning:

• Wash the interior and exterior of the vial in a detergent solution.

• After washing, rinse the vial thoroughly 8 to 10 times with clean distilled water to eliminate detergent buildup and streaking.

• For periodic deep cleaning, vials can be acid washed.

Handling and Preparation:

• Always handle sample vials from the top or by the cap to avoid fingerprints or smudges.

• After filling a vial with a sample and capping it, wipe the outside surface with a clean, lint-free absorbent cloth until it is dry.

• You can coat the vial with the special silicone oil provided to fill small scratches and mask imperfections in the glass. Apply a small amount and wipe off the excess with a lint-free cloth. The result should be a dry appearance.

Storage:

• Store cleaned and dried vials with the black caps on.

• The vials can be stored in the carrying case.

Dealing with Condensation:

If your sample is very cold and the relative air humidity is high, condensation may appear on the vial, leading to higher turbidity readings. To alleviate this, you can either coat the vial with an anti-fogging agent or run warm water over the vial for a short period to warm the sample prior to measurement.

The United States Environmental Protection Agency (US EPA) recommends that vials used for turbidimeter calibration or sample measurement be indexed.

To index a sample vial, slowly rotate the vial throughout one complete revolution (360°). While rotating the sample vial, observe the display (using the continuous measurement mode) and locate the position that the vial is in which provides the lowest turbidity reading. This position is the indexed position of the vial.

Mark this position on the vial (not on the cap) against the mark on the meter.

After indexing a vial, make sure the vial will always be placed inside the sample well in the indexed position.

Best accuracy and repeatability are achieved using a single, indexed vial. However, for more convenience, different vials can be used if their readings with the same solution are matched.

1. Select a few vials. After the sample vials are cleaned, fill them with ultra-low turbidity water.

2. Allow the sample vials to stand and for air bubbles to rise.

3. Polish sample vials with silicone oil and take a turbidity measurement at several points while rotating it in the sample well. Find the position where the turbidity reading is the lowest and index it for each vial.

4. Whenever these sample vials are used, use the indexed mark to position each vial into the sample well.

5. Choose those vials that match the readings (i.e., the meter gives identical readings or readings within the specified repeatability and accuracy of the meter).

NOTE: Not all vials can be matched because of some manufacturing variations.

Air or other trapped gases should be removed before measurement. Degassing is recommended even if no bubbles are visible. There are three methods commonly used for degassing:

• Addition of a surfactant: This involves adding a surfactant to the water samples to lower the surface tension of the water, thereby releasing trapped gasses.

• Application of a partial vacuum: Partial vacuum can be created by using a simple syringe or vacuum pump. (This is only recommended for ultra-low turbidity measurement).

• Use of an ultrasonic bath: This may be effective in severe conditions or in viscous samples, but not recommended for ultra-low measurements.

Each method has its own advantages and disadvantages. For instance, under certain sample conditions, the use of a vacuum pump or ultrasonic bath may actually increase the presence of gas bubbles.

1. Samples should not be violently shaken or agitated as particles can be broken apart or air may be entrapped into the fluid. Gentle agitation such as swirling the sample vial is advisable to reduce particle settling.

2. Sample vials should be used only with the instruments for which they were intended. Do not mix and match.

3. Perform a visual observation of the sample vial every time a measurement is made. Ensure that there are no visible bubbles in the sample and the vial is clean and free of scratches.

4. Samples entering the turbidimeter should be at the same temperature as the process flow samples. Changes in temperature can cause precipitation of soluble compounds and affect readings.

5. Sample vials should be evaluated with a low turbidity water (after cleaning) to determine if cells remain matched. If the evaluation determines that a cell is corrupted, discard the vial. It is recommended to conduct this evaluation weekly.

6. When in doubt or question about whether a sample vial is too scratched or stained, throw it away.

1. Do not open the vials with calibration standards.

2. Check that the standards have not expired.

3. Make sure the calibration vials are free of dust, smudges and scratches before use.

4. Conduct the calibration in the same manner each time. Variations in how calibration is performed could yield inaccurate measurements.

5. It is very important that the user(s) who perform calibration have been trained to do so. Creating a Standard Operating Procedure (SOP) for the user(s) to read, learn, and practice may help to ensure accuracy.

This dilution procedure is necessary only when your turbidity measurement is above 1000 NTU.

1. To measure the turbidity above 1000 NTU, dilute the sample with turbidity-free water.

2. Turbidity-free water can be obtained by filtering deionized water through a < 0.2µm filter membrane with precision-sized pores.

3. Measure the volume of the sample before dilution and record the value in ml (Vs).

4. Take a known volume (Vd) of dilution water and add it to the sample.

5. Pour 10 ml of the diluted sample in a clean vial and measure the turbidity of the diluted sample. Record this value in NTU (Td).

6. Calculate the true turbidity (T) of the original sample – in NTU – using the following formula:

T = Td * (Vs + Vd) / Vs

Example:

• Dilute 20 ml of the original sample (whose turbidity is above 1000NTU) with 50 ml of dilution water.

• Measure the turbidity of the diluted sample.

• If the reading is 300 NTU, the turbidity of the original sample is 1050 NTU. (In this case: Td=300NTU, Vs=20ml, Vd=50ml, so T = 300 * (20+50) / 20 = 300*70/20 = 21000/20 = 1050)