Instruction Manual

HI 9142

Portable Waterproof

Dissolved Oxygen Meter

w w w . h a n n a i n s t . c o m

Dear Customer,

Thank you for choosing a Hanna Instruments

Product.

Please read this instruction manual carefully before using the instrument.

This manual will provide you with all the necessary information for the correct use of the instrument.

If you need additional technical information, do not hesitate to e-mail us at

[email protected]

This instrument is in compliance with the CE directives.

TABLE OF CONTENTS

Preliminary Examination ............................. 3

General Description ..................................... 3

Probe Functional Description ...................... 4

Meter Functional Description ....................... 5

Specifications ............................................. 6

Probe Initial Preparation .............................. 7

Calibration Procedure .................................. 8

Taking Measurements ............................... 10

Altitude and Salinity Compensation ........... 11

Probe & Membrane Maintenance .............. 13

Battery Replacement ................................ 15

Accessories .............................................. 16

Warranty ................................................... 17

CE Declaration of Conformity .................... 18

2

PRELIMINARY EXAMINATION

Remove the instrument from the packing material and examine it to make sure that no damage has occurred during shipping. If there is any damage, notify your Dealer.

The meter is supplied complete with:

•

HI 76407/4 DO probe with 4 m cable

•

2 spare membranes with O-rings

•

HI 7041S electrolyte solution (30 mL)

•

Calibration screwdriver

•

Batteries (4 x 1.5V AA)

•

Instruction manual

•

Rugged carrying case

Note:

Save all packing material until you are sure that the instrument functions correctly. All defective items must be returned to us in the original packaging with the supplied accessories.

GENERAL DESCRIPTION

HI 9142 is a rugged, waterproof meter that solves the common problems of field use, such as cold, rain, snow and dust, that can damage a meter, rapidly deteriorating its performance and life.

It is very simple to use: calibration is performed with HI 7040 zero oxygen solution, while 100% calibration is done in air.

The polarographic probe (HI 76407/4) is provided with a membrane covering the sensors and a built-in thermistor for temperature measurement and compensation. The thin permeable membrane isolates the sensor elements from the testing solution, but allows oxygen to enter. When a voltage is applied across the sensor, oxygen that has passed through the membrane reacts causing current to flow, allowing the determination of oxygen.

3

The probe included with the meter is supplied with a 4 m (13') cable that allows measurements to be taken even in even hard to reach places. For applications that require longer probe cables, the HI 76407/10 and HI 76407/20 probes with a 10 m (33') or 20 m (67') cable are available.

PROBE FUNCTIONAL DESCRIPTION

3

1

4

6

7

8

4

9

5

6

7

8

9

1. D.O. probe

2. Protective cap

3. Shielded cable

4. Polypropylene probe body

5. Temperature sensor

6. O-Ring seal

7. Silver chloride (AgCl) anode

8. Platinum cathode (sensor)

9. Oxygen permeable membrane

10.Membrane cap

4

2

10

METER FUNCTIONAL DESCRIPTION

1.

Battery compartment

2.

Probe connector

3.

Liquid Crystal Display

4.

ON/OFF button

5.

Calibration button

6.

Slope calibration trimmer

7.

Zero oxygen calibration trimmer

5

SPECIFICATIONS

Range

Resolution

Accuracy

Dimensions

Weight

0.0 to 19.9 mg/L (ppm)

0.1 mg/L

±1.5% FS

Typical EMC

Deviation

Calibration

±0.8 mg/L with 4 m cable probe

Manual, 1 or 2 point

(zero and slope)

Temperature

Compensation

Probe

Automatic, 0 to 30°C

(32 to 86°F)

HI 76407/4, polarographic, with 4 m (13') cable (included)

Battery Type

Life

Environment

4 x 1.5V AA approx. 500 hours of use

0 to 50°C (32 to 122°F);

RH max 100%

196 x 80 x 60 mm

(7.7 x 3.1 x 2.4")

500 g (1.1 lb.)

6

PROBE INITIAL PREPARATION

Probe Preparation

All D.O. probes from Hanna Instrument are shipped dry. To hydrate the probe and prepare it for use, connect it to the meter and proceed as follows.

1. Remove the red & black plastic cap. This cap is used for shipping purposes only and can be

Shipping cap

thrown away.

2. Wet the sensor by soaking the bottom (2.5 cm/1") of the probe in HI 7041S electrolyte solution for 5 minutes.

3. Rinse the membrane

(HI 76407A supplied with the meter) with

black red

some electrolyte while shaking it gently. Refill with clean electrolyte.

4. Gently tap the sides of the membrane with your finger to ensure that no air

FILL FIRST

THEN TAP

bubbles remain trapped inside.

THEN SCREW

BACK ON

To avoid damaging the membrane, do not tap the membrane directly on the bottom.

5. Place the rubber O-Ring properly inside the membrane cap.

6. With the sensor facing down, screw the cap clockwise. Some electrolyte will overflow.

When not in use and during polarization, protect the membrane with the supplied cap.

7

CALIBRATION PROCEDURE

PROBE POLARIZATION

The probe is under polarization with a fixed voltage of approximately 800 mV.

Probe polarization is essential for stable measurements with the same recurring degree of accuracy.

With the probe properly polarized, oxygen is continually "consumed" by passing through the sensitive diaphragm and dissolving in the electrolyte solution contained in the probe.

If this operation is interrupted, the electrolyte solution continues to be enriched with oxygen until it reaches an equilibrium with the surrounding solution.

Whenever measurements are taken with a nonpolarized probe, the oxygen level revealed is both that of the tested solution as well as that present in the electrolyte solution. This reading is incorrect

The calibration is very simple and fast.

• Make sure the probe is ready for measurements (see initial preparation at page 7), i.e.

the membrane is filled with electrolyte and the probe is connected to the meter.

• Switch the meter on by pressing the ON/OFF key

• For an accurate calibration, it is recommended that you wait at least 15 minutes to ensure precise conditioning of the probe.

• Remove the protective cap from the D.O. probe.

ON/OFF

8

ZERO CALIBRATION

• Dip the probe into HI 7040 zero oxygen solution and stir gently for 2-3 minutes.

• Allow 2 minutes for the LCD readout to stabilize.

• Adjust the zero D.O. calibration trimmer until the display reads "0.0".

Note The zero calibration screw is located close to the probe connector.

SLOPE CALIBRATION

It is suggested to perform the slope calibration in satured air.

• Rinse the probe in a large amount of clean water to remove any residual zero oxygen solution.

• Dry the probe tip and allow a few minutes for the LCD readout to stabilize.

• Press and hold the CAL key.

• Adjust the slope trimmer on the top of the meter to read

"100%" on the LCD (while still holding the CAL button).

Note The slope calibration screw is located farthest from the probe connection.

• Release the CAL key and the

LCD will display the value in ppm of oxygen.

CAL

%

The zero calibration of the HI 9142 is very stable, therefore this procedure needs only to be performed whenever the probe is re-

placed.

However, because the slope calibration is more critical, it is recommended to perform

this procedure every week.

9

TAKING MEASUREMENTS

Make sure the meter has been calibrated and the protective cap has been removed. Immerse the tip of the probe in the sample to be tested.

Make sure the temperature sensor is also immersed.

For accurate dissolved oxygen measurements a water movement of 0.3 m/sec is required at a minimum. This is to ensure that the oxygendepleted membrane surface is constantly replenished. A moving stream will provide adequate circulation. To quickly check if the water speed is sufficient, wait for the reading to stabilize and then move the D.O. probe. If the reading is still stable, the measurement conditions are right, while if the reading increases the water movement is not adequate.

During field measurements, this condition may be met by manually agitating the probe. Accurate readings are not possible while the liquid is at rest.

During laboratory measurements, the use of a magnetic stirrer to ensure a certain velocity in the fluid is recommended. In this way, errors due to the diffusion of the oxygen present in the air in the solution are reduced to a minimum.

At all times, time necessary for thermal equilibrium to occur between the probe and the sample must be allowed (a few minutes for temperature difference of several degrees).

10

ALTITUDE & SALINITY COMPENSATION

°C

26

28

30

32

34

16

18

20

22

24

36

38

40

6

8

10

12

14

0

2

4

If the sample contains salts or if you are performing the measurements at a different altitude than sea level, the readout values must be corrected, taking into account the lower degree of oxygen solubility.

ALTITUDE COMPENSATION

All the readouts are referred at sea level, thus the displayed measurements are higher than the actual values. In fact, altitude affects D.O.

concentration decreasing its value. The following table reports the oxygen solubility at various temperatures and altitudes, based on sea level barometric pressure of 760 mm Hg.

0 m

Altitude, Meters above Sea Level

300 m 600 m 900 m 1200 m 1500m 1800m

7.5

7.3

7.1

6.8

6.6

6.4

9.1

8.7

8.4

8.1

7.8

14.6

13.8

13.1

12.4

11.8

11.3

10.8

10.3

9.9

9.5

7.2

7.1

6.9

6.6

6.4

6.2

8.8

8.4

8.1

7.8

7.5

14.1

13.3

12.7

12.0

11.4

10.9

10.4

9.9

9.7

9.2

13.6

12.9

12.2

11.6

11.0

10.5

10.1

9.6

9.2

8.7

8.5

8.1

7.8

7.5

7.3

7.0

6.8

6.6

6.3

6.2

6.0

13.2

12.4

11.9

11.2

10.6

10.2

9.7

9.3

8.9

8.6

8.2

7.8

7.5

7.3

7.0

6.8

6.6

12.7

12.0

11.4

10.8

10.3

9.8

9.4

9.0

8.6

8.3

7.9

7.7

7.3

7.0

6.8

6.5

6.4

12.3

11.6

11.0

10.4

9.9

9.5

9.1

8.7

8.3

8.0

7.7

7.3

7.1

6.8

6.6

6.3

6.1

6.4

6.2

6.0

6.1

5.9

5.7

5.9

5.7

5.6

5.8

5.6

5.4

7.4

7.1

6.8

6.6

6.3

6.1

5.9

5.8

5.5

5.4

5.2

9.2

8.8

8.3

8.0

7.7

11.8

11.2

10.6

10.1

9.6

°F

71.6

75.2

78.8

82.4

86.0

89.6

93.2

96.8

100.4

104.4

32.0

35.6

39.2

42.8

46.4

50.0

53.6

57.2

60.8

64.4

68.0

This gives an idea of the error that can be introduced at different altitudes and allows you to calculate the quantity to be subtracted to correct your reading.

11

SALINITY COMPENSATION

The table below shows the influence of salt in the measurement of oxygen.

In HI 9142 all the readouts are referred to 0 g/l of salinity value. In fact, salinity affects D.O.

concentration decreasing its value.

For your reference the table below reports the oxygen solubility at various temperatures and salinity. From the table you can calculate the quantity to be subtracted to correct your reading.

°C

10

12

14

16

18

20

22

24

26

28

0 g/l

Salinity (g/l) at Sea Level

10 g/l 20 g/l 30 g/l 35 g/l

11.3

10.8

10.3

9.9

9.5

9.1

8.7

8.4

8.1

7.8

10.6

10.1

9.7

9.3

8.9

8.5

8.2

7.9

7.6

7.4

9.9

9.5

9.1

8.7

8.4

8.0

7.8

7.5

7.2

7.0

9.3

8.9

8.6

8.2

7.9

7.6

7.3

7.1

6.8

6.6

°F

9.0

8.6

8.3

8.0

7.6

7.4

7.1

6.9

6.6

6.4

50.0

53.6

57.2

60.8

64.4

68.0

71.6

75.2

78.8

82.4

12

PROBE & MEMBRANE MAINTENANCE

The oxygen probe body is made of reinforced plastic for maximum durability.

A thermistor temperature sensor provides temperature measurement and compensation. When not in use, it is always recommended to protect the probe against damage and dirt using the supplied cap.

To replace the membrane or refill with electrolyte, proceed as follows:

• Remove the protective cap by gently twisting and pulling it off (see fig. 1).

• Unscrew the membrane by turning it counterclock-wise (see fig. 2)

• Wet the sensor by soaking the bottom (2.5 cm) of the probe in HI 7041S electrolyte solution for 5 minutes.

• Rinse the new membrane

(HI 76407A supplied with the meter) with some electrolyte while shaking it gently. Refill with clean electrolyte.

• Gently tap the sides of the membrane with your finger to ensure that no air bubbles remain trapped inside. Do no directly tap the bottom as this will damage the membrane.

• Make sure that the rubber

O-ring is seated properly inside the membrane cap.

TWIST

AND

PULL

fig. 1

UNSCREW fig. 2

13

• With the sensor facing down, screw the membrane cap clock-wise. Some electrolyte will overflow.

The Platinum cathode (#8 in the Functional

Description at page 4) should always be bright and untarnished. If it is tarnished or stained, which could be due to contact with certain gases or extended use with a loose or damaged membrane, the cathode should be cleaned.

Use a lint-free cardboard or cloth and rub the cathode very gently side to side 4-5 times. This will be enough to polish and remove any stains without damaging the platinum tip. Afterwards, rinse the probe with deionized or distilled water and install a new membrane cap using fresh electrolyte. Recalibrate the instrument.

Important: In order to have accurate and stable measurements, it is important that the surface of the membrane is in perfect condition. This semi-permeable membrane isolates the sensor elements from the environment but allows oxygen to enter. If any dirt is observed on the membrane, rinse carefully with distilled or deionized water. If any imperfection still exists, or any damage is evident (such as wrinkles or tears), the membrane should be replaced. Make sure that the O-Ring is properly seated in the membrane cap.

BATTERY REPLACEMENT

When the battery level is low,

"V" is displayed on the LCD to warn the user that the battery needs to be replaced.

V

The meter will still work for approximately 4 hours, then the display will be shut-off to avoid erroneous readings.

Battery replacement must only take place in a safe area and using alkaline 1.5V AA type batteries.

In order to replace the batteries, simply remove the two screws on the rear cover of the instrument and replace all four batteries with new ones, while paying attention to the correct polarity.

14

15

ACCESSORIES

HI 7040M

HI 7040L

HI 7041S

HI 76407/4

HI 76407/10

HI 76407/20

HI 76407A/P

Zero oxygen solution, 230 mL

Zero oxygen solution, 500 mL

Refilling electrolyte solution,

30 mL

D.O. probe with 4 m (13') cable

D.O. probe with 10 m (33') cable

D.O. probe with 20 m (66') cable

D.O. membrane (5 pcs)

16

WARRANTY

All Hanna Instruments meters are warranted

for two years against defects in workmanship and materials when used for their intended purpose and maintained according to the instructions. The probes are warranted for a

period of six months.

Damages due to accidents, misuse, tampering or lack of prescribed maintenance are not covered. This warranty is limited to repair or replacement free of charge.

If service is required, contact the dealer from whom you purchased the instrument. If under warranty, report the model number, date of purchase, serial number and the nature of the failure. If the repair is not covered by the warranty, you will be notified of the charge for repair or replacement. If the instrument is to be returned to Hanna Instruments, obtain a Return

Goods Authorization from the Customer Service Department first and then send it with shipment cost prepaid. When shipping any instrument, make sure it is properly packaged for complete protection.

All rights are reserved. Reproduction in whole or in part is prohibited without the written consent of the copyright owner.

Hanna Instruments reserves the right to modify the design, construction and appearance of its products without advance notice.

17

CE DECLARATION OF CONFORMITY

Recommendations for Users

Before using this product, make sure that it is entirely suitable for the environment in which it is used.

Operation of this instrument in residential area could cause unacceptable interferences to radio and TV equipments, requiring the operator to take all necessary steps to correct interferences.

Any variation introduced by the user to the supplied equipment may degrade the instrument's EMC performance.

To avoid electrical shock, do not use this instrument when voltages at the measurement surface exceed 24 Vac or 60 Vdc.

To avoid damages or burns, do not perform any measurement in microwave ovens.

In particular cases the meter could turn off. In these cases it can be turned on by pressing the ON/OFF key.

18

19

SALES & TECHNICAL SERVICE CONTACTS

Australia:

Tel. (03) 9769.0666 • Fax (03) 9769.0699

China:

Tel. (10) 88570068 • Fax (10) 88570060

Egypt:

Tel. & Fax (02) 2758.683

Germany:

Tel. (07851) 9129-0 • Fax (07851) 9129-99

Greece:

Tel. (210) 823.5192 • Fax (210) 884.0210

Indonesia:

Tel. (21) 4584.2941 • Fax (21) 4584.2942

Japan:

Tel. (03) 3258.9565 • Fax (03) 3258.9567

Korea:

Tel. (02) 2278.5147 • Fax (02) 2264.1729

Malaysia:

Tel. (603) 5638.9940 • Fax (603) 5638.9829

Singapore:

Tel. 6296.7118 • Fax 6291.6906

South Africa:

Tel. (011) 615.6076 • Fax (011) 615.8582

Taiwan:

Tel. 886.2.2739.3014 • Fax 886.2.2739.2983

Thailand:

Tel. 66.2619.0708 • Fax 66.2619.0061

United Kingdom:

Tel. (01525) 850.855 • Fax (01525) 853.668

USA:

Tel. (401) 765.7500 • Fax (401) 765.7575

For e-mail contacts and complete list of Sales and

Technical offices, please see www.hannainst.com