EUTECH INSTRUMENTS TURBIDIMETER TN-100 WATERPROOF PORTABLE METER Manual de Instruções descarregar pdf (Página 3)

6. Wait for the reading to stabilize.

1 INTRODUCTION

7. Slowly rotate the vial throughout one complete revolution (360°). While rotating, observe the display

and locate the position with the lowest turbidity reading. This position is the indexed position.

This manual contains the operating features of this meter. At some points this manual will refer to our

website

www.eutechinst.com,for further explanation and background information, it will be indicated

with this symbol:

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

9. Release READ/ENTER.

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

On this website you can also find additional information regarding applications, measuring theories and

hints & tips.

6 OTHERS

At the final page of this manual you can find information about the specifications of this meter, warranty

issues and how to return your product to us.

6.1 Nephelometric Turbidity Units (NTU)

Nephelometric Turbidity Units (NTU) is the accepted unit of measurement for turbidity. Another unit

commonly used is Formazin Turbidity Unit (FTU). The two units are equivalent: 1 NTU = 1 FTU.

This instrument operates on the nephelometric principle of turbidity measurement and is designed to

meet the criteria specified in ISO 7027 and DIN 27027 standards.

6.2 Sampling Techniques

¾ Samples should not be violently shaken or agitated, particles can be broken apart or air may be

entrapped Gentle agitation such as swirling the sample vial is advisable to reduce particle settling.

¾ Sample vials should be used only with the instruments for which they were intended. Do not mix

and match.

¾ 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.

¾ Samples entering the turbidity meter should be at the same temperature as the process flow

samples. Changes in temperature can cause precipitation of soluble compounds and affect

readings.

¾ 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.

6.3 Dilution

Dilution is necessary only when the turbidity measurement is above 1000 NTU.

1. Dilute the sample with turbidity-free water. Turbidity-free water can be obtained by filtering

deionized water through a < 0.2µm filter membrane with precision-sized pores.

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

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

4. 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).

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

¾ T = Td * (Vs + Vd) / Vs

Example: Dilute 20 ml of the 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. (Td=300NTU, Vs=20ml,

Vd=50ml, so T = 300 * (20+50) / 20 = 300*70/20 = 21000/20 = 1050)

7 MAINTENANCE

7.1 Meter

It is advisable to store the meter in the carrying case, otherwise, ensure that a clean capped sample

vial has been placed in the sample well. This will ensure that a minimal of dust and/or debris will settle

on the optics of the instrument.

7.2 Handling the vial

Vials should always be handled from the top or by the cap. After filling and capping a vial the vial

should be wiped with a clean, lint-free absorbent cloth until it is dry. During normal operation typical

glass cleaner along with a lint free cloth or tissue can be used, to clean the outside of the vials.

Condensation can be avoided by coating the vial with an anti-fogging agent, or by running warm water

over the vial for a short period to warm the sample prior to measurement.

2 DISPLAY & KEYPAD FUNCTIONS

2.1 Display

The LCD shows the reading and the display has several

annunciators for error messages and user guidance.

It has the following indicators:

1. Calibration Standards

2. Battery indicator

3. Units of Measurement

4. 14 segment LCD

2.2 Keypad

The keypad has five keys:

KEY Function

ON/OFF

Powers on and shuts off the meter. With the auto switch-off feature the meter automatically

shuts off 20 minutes after last key press.

CAL

Initiates calibration mode. When pressed, the meter is set to accept the first calibration

standard or to exit the calibration wihout completing the procedure.

READ /

ENTER

- READ/ENTER key is used to perform a measurement.

- Single-shot measurements: When the key is pressed and released immediately, the

display will blink [-Rd-] for 10 times and then display the measured value.

- Continuous measurements: If pressed and held, the instrument will perform a continuous

measurement during which the display is updated every 2 seconds.

- READ/ENTER key is used to confirm the measurement for the calibration standards.

▲and▼

- to select the calibration point in an incremental/ decremental manner.

3 BATTERY INSTALLATION

3.1 Inserting the Batteries

Four AAA-sized batteries are included with your meter:

1. Use a screwdriver to remove the two screws of 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.

1 2 3 4

TN-100 / T100 1

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