NOVEX 98.490 ABBE Refractometer User Manual

NOVEX 98.490 ABBE Refractometer

Product Information

The NOVEX Abbe Refractometer is a high-quality product designed for use in laboratories and the food industry. It requires minimal maintenance when used properly. This instrument consists of a main body, stand foot, and a measuring part consisting of a primary and secondary prism. The refractometer also includes an adjustable eyepiece, dispersion correction knob, water connections, adjustment knob, scale window, reflection mirror, light window, thermometer, and prism cover.

Product Usage Instructions

Preparing the Refractometer for Use

1. Remove the instrument from the aluminum case and place it on a flat surface.
2. Remove the black protection cap from the thermometer and screw the thermometer gently into its inlet on the main body, situated at the side of the primary prism.

Calibrating the Refractometer

Before measuring liquid samples, calibrate the refractometer using the supplied test piece and immersion fluid:

1. Place the test piece on the primary prism and close the secondary prism.
2. Look through the eyepiece and focus on the cross line.
3. If the scale with cross is not aligned with the Brix scale or nD scale, adjust the scale by turning the set screw (B) with the supplied driver.

Measuring Liquid Samples with the Refractometer

1. Put some drops of the sample fluid onto the primary prism and close the secondary prism by means of the knob (P). Make sure the sample is homogeneous and without air bubbles.
2. Open the light cap (N) and close the reflection mirror (J).
3. Peep through the eyepiece and focus the cross line.
4. Turn the illumination window (H) of the scale until the brightest image is reached.
5. Move the cross with knob (F) until it is exactly at the borderline of the dark and light image.
6. Correct color shifting in the image to black/white by means of the dispersion knob (C).
7. Make a final correction to get the cross exactly on the border line with knob (F).
8. Read the refractive index value (nD) on the bottom part of the scale.

Measuring Sugar Percentage in a Liquid

1. Put some drops of the sample fluid onto the primary prism and close the secondary prism by means of the knob (P). Make sure the sample is homogeneous and without air bubbles.
2. Follow steps 2-7 in “Measuring Liquid Samples with the Refractometer.”
3. Read the sugar percentage on the Brix scale.

Maintenance and Cleaning

Clean the refractometer after each use by wiping it with a soft, dry cloth. If necessary, clean with a damp cloth and mild detergent, then dry thoroughly. Do not use solvents or abrasive cleaners.

Refractometer Accessories

The refractometer comes with a test piece, immersion fluid, and a driver for adjusting the scale set screw (B). Additional accessories are available from Euromex Microscope B.V.

Introduction

With your purchase of the NOVEX Abbe refractometer you have chosen for a quality product. The NOVEX Abbe refractometer is developed for use in laboratories and in the food industry. The maintenance requirement is limited when using the refractometer in a decent manner. This manual describes the construction of the refractometer, how to use the refractometer and maintenance of the refractometer.

Index

1. Introduction
2. Index
3. Construction of the refractometer
4. Functions of the refractometer
5. preparing the refractometer for use
6. Working with the refractometer
7. Maintenance and cleaning
8. Refractometer accessories

Construction of the refractometer

The names of the several parts are listed below and are indicated in the picture:

• Adjustable eyepiece
• Main body
• Dispersion correction knob
• Water connection (in-out)
• Water connection (out)
• Adiustment knob
• Stand foot
• Scale window (not visible) Water connection (in)
• Reflection mirror
• Primary prism
• Light window
• Secondary prism
• Cover light window
• Thermometer
• Prism cover

Functions of the refractometer

The instrument consists of a main body (B), stand foot (G) and a measuring part consisting of a primary- (K) and a secondary prism (M). When moving the instrument always pick it up by its main body.

Preparing the refractometer for use

Remove the instrument from the alluminium case and place it on a flat surface.
Remove the black protection cap from the thermometer and screw the thermometer gently in its
inlet on the main body, which is situated at the side of the primary prism (K).

Working with the refractometer

For optimum use please follow the below procedures.

Calibrating the refractometer

Before measuring the instrument should be calibrated with the supplied test piece and immersion fluid, this should be done as described below:

• Put some drops of the immersion fluid onto the surface of the primary prism (K).
• Gently put the test piece into the fluid, with the polished side pointing downwards.
• Peep though the eyepiece and turn the eyepiece until the image is sharply focused.
• Now turn the adjustment knob F until the cross exactly separates the light and dark image in the field of view.
• The scale should now read exactly the same value as mentioned on the test piece. If this is not the case, adjust the scale by turning the set screw (B) with the supplied driver.

Measuring liquid samples with the refractometer

1. Put some drops of the sample fluid onto the primary prism (K), en close the secondary prism (M) by means of the knob (P). Make sure the sample is homogeneous and without air bubbles.
2. Open the light cap (N) and close the reflection mirror (J).
3. Peep through the eyepiece (A) and focus the cross line.
4. Turn the illumination window (H) of the scale until the brightest image is reached.
5. Now move the cross with knob (F) until it is exactly at the border line of the dark and light image.
6. Colour shifting in the image can be corrected to “black/white” by means of the dispersion knob (C).
7. Now a last correction to get the cross exactly on the border line can be made with knob (F). The refractive index value (nD) can now be read on the bottom part of the scale.

Measuring the sugar percentage in a liguid

1. Put some drops of the sample fluid onto the primary prism (K), en close the secondary prism (M) by means of the knob (P). Make sure the sample is homogeneous and without air bubbles.
2. Open the light cap (N) and close the reflection mirror (J).
3. Peep through the eyepiece (A) and focus the cross line.
4. Turn the illumination window (H) of the scale until the brightest image is reached
5. Now move the cross with knob (F) until it is exactly at the borderline of the dark and light image.
6. Colour shifting in the image can be corrected to “black/white by means of the dispersionknob (C).
7. Now a last correction to get the cross exactly on the borderline can be made with knob (F). The sugar percentage (BRIX) can now be read on the upper part of the scale.

Measuring clear-transparent solid materials (e.g. glass)

Note!

• Make sure one of the sides of the sample is perfectly smooth. STOP

1. Put some drops of the supplied immersion fluid onto the primary prism (K)
2. Carefully place the specimen with its smooth side into the fluid
3. Open the light cap (N) and close the reflection mirror (J).
4. Peep through the eyepiece (A) and focus the cross line.
5. Turn the illumination window (H) of the scale until the brightest image is reached
6. Now move the cross with knob (F) until it is exactly at the border line of the dark and light image.
7. Colour shifting in the image can be corrected to “black/white” by means of the dispersion knob (C).
8. Now a last correction to get the cross exactly on the border line can be made with knob (F). The refractive index can now be read on the bottom part of the scale.

Establishing the dispersion value Dec

1. Put some drops of the sample fluid onto the primary prism (K), en close the secondary prism (M) by means of the knob (P). Make sure the sample is homogeneous and without air bubbles.
2. Open the light cap (N) and close the reflection mirror (J).
3. Peep through the eyepiece (A) and focus the cross line.
4. Turn the illumination window (H) of the scale until the brightest image is reached.
5. Now move the cross with knob (F) until it is exactly at the border line of the dark and light image.
6. Correct the dispersion with the knob (C) and write down the value “Z” (to read on the side of knob C). If “Z” is higher as 30, write “Z” as a negative number.
7. Now a last correction to get the cross exactly on the border line can be made with knob (F).
8. The refractive index can now be read on the bottom part of the scale.
9. Take the values of “A”. “B” and “o” over from the table on page 9 of this manual with the use of the values “Z” en nD, written down on point 6.
10. Use the values for the below formula:

Dec = A + 0B

Calculation example 1. measured values with 2 decimals behind the comma:

• Measured at 22°C:
• nD liquid: 1.3300
• Dispersion correction Z: 40.0

Found values A and B in the nD column in table 6.7:

• A = 0.02484
• B = 0.03304

Found value o in the Z column in table Z;

• -0.500 (negative value for Z is higher as 30)
• Dec = A + 0B
• D=c = 0.02484 + (0.03304 x -0.500)
• DFc = 0.00832

Calculation example 2, measured values with more as 2 decimals behind the

comma:

• Measured at 20°C:
• ND distilled water: 1.3330*
• Dispersion correction Z: 41.62*
• In the table the measured values nD 1.3330 and “Z” value 41.62 are not included, therefor calculate “A”, “B” and “o” as follows:
• Take the nD value 1.33 (or the corresponding “Z” value) from the table and read the correct value (in this case – 5×10 per 0.001) and add it to the value of “A” given for 1.33 1.3330 -1.33 = 0.003 so the correcting value is: 3 x – 5 × 10% = 0.000015
• The for 1.33 given “‘ value is 0.02484 so the corrected “A” value for nD 1.3330 is: 0.02484 + 0.000015 = 0.024825.
• Repeat the these steps also for the “B” and “o” values.

Results:

• 0.024825
• 0.032983
• -0.5716 (negative value for Z is higher as 30)
• A + 0B
• 0.024825 + (0.032983 x -0.5716)
• 0.005972

Table dispersion values

ND

|

A

| 0.001

decimal correction for A

x (10–6 )

|

B

| 0.001

decimal correction for B

x (10- 9 )

|

Z

|

σ

| 0.1

decimal correction for σ

x (10–4 )

|

Z

---|---|---|---|---|---|---|---|---
1.30000| 0.02499| -5| 0.03349| -13| 0| 0.000| | 60
1.31000| 0.02494| -5| 0.03336| -16| 1| 0.999| 1| 59
1.32000| 0.02489| -5| 0.03320| -16| 2| 0.995| 4| 58
1.33000| 0.02484| -5| 0.03304| -10| 3| 0.988| 7| 57
1.34000| 0.02479| -5| 0.03285| -20| 4| 0.978| 10| 56
1.35000| 0.02474| -4| 0.03265| -21| 5| 0.966| 12| 55
1.36000| 0.02470| -4| 0.03244| -22| 6| 0.951| 15| 54
1.37000| 0.02466| -5| 0.03221| -34| 7| 0.934| 17| 53
1.38000| 0.02461| -4| 0.03197| -27| 8| 0.914| 20| 52
1.39000| 0.02457| -3| 0.03170| -27| 9| 0.891| 23| 51
1.40000| 0.02454| -4| 0.03143| -30| 10| 0.866| 52| 50
1.41000| 0.02450| -3| 0.03113| -31| 11| 0.839| 27| 49
1.42000| 0.02447| -4| 0.03082| -32| 12| 0.809| 30| 48
1.43000| 0.02443| -3| 0.03050| -35| 13| 0.777| 32| 47
1.44000| 0.02440| -2| 0.03615| -36| 14| 0.743| 34| 46
1.45000| 0.02438| -2| 0.02979| -38| 15| 0.707| 36| 45
1.46000| 0.02435| -2| 0.02941| -39| 16| 0.669| 38| 44
1.47000| 0.02433| -3| 0.02902| -42| 17| 0.629| 40| 43
1.48000| 0.02430| -2| 0.02860| -43| 18| 0.588| 41| 42
1.49000| 0.02428| -1| 0.02817| -46| 19| 0.545| 43| 41
1.50000| 0.02427| -2| 0.02771| -47| 20| 0.500| 45| 40
1.51000| 0.02425| -1| 0.02724| -49| 21| 0.454| 46| 39
1.52000| 0.02424| -1| 0.02675| -52| 22| 0.407| 47| 38
1.53000| 0.02423| 0| 0.02623| -54| 23| 0.358| 49| 37
1.54000| 0.02423| 0| 0.02569| -56| 24| 0.309| 49| 36
1.55000| 0.02423| 0| 0.02513| -59| 25| 0.259| 50| 35
1.56000| 0.02423| 0| 0.02454| -61| 26| 0.208| 51| 34
1.57000| 0.02424| +1| 0.02393| -64| 27| 0.156| 52| 33
1.58000| 0.02425| +1| 0.02329| -64| 28| 0.104| 52| 32
1.59000| 0.02426| +1| 0.02262| -67| 29| 0.052| 52| 31
1.60000| 0.02428| +2| 0.02192| -70| 30| 0.000| 52| 30
1.61000| 0.02430| +2| 0.02119| -73| | | |
1.62000| 0.02433| +3| 0.02042| -77| | | |
1.63000| 0.02437| +4| 0.01962| -80| | | |
1.64000| 0.02442| +5| 0.18877| -85| | | |
1.65000| 0.02447| +5| 0.01788| -89| | | |
1.66000| 0.02453| +6| 0.01694| -94| | | |
1.67000| 0.02461| +8| 0.01594| -100| | | |
1.68000| 0.02470| +9| 0.01487| -107| | | |
1.69000| 0.02480| +10| 0.01373| -114| | | |
1.70000| 0.02493| +13| 0.01250| -123| | | |

The use of circulating water

For use in so-called “on-line” situations, it can be important to keep the temperature of the sample fluid on a constant level. The refractometer can be linked to a water circulator to keep the prisms of the refractometer on a constant temperature. Therefore the connection points of the circulation system should be connected to each other by means of flexible rubber hoses (not supplied). Proceed as follows:

• The water supply should be connected to connection point “I”.
• Connection point “E” should be connected to one of connection points “D”.
• The last connection point should be used for the discharge.

Refractive indices and average dispersion values of distilled water

As example dispersion values and D values corrected at temperatures of 10 – 40°C are given.

Temp in °C| Refractive index in nD| Dispersion value

D FC

| Temp in

°C

| Refractive index in nD| Dispersion value

D FC

---|---|---|---|---|---
10| 1.33369| 0.00600| 33| 1.33157| 0.00593
11| 1.33364| 0.00600| 34| 1.33144| 0.00593
12| 1.33358| 0.00599| 35| 1.33131| 0.00592
13| 1.33352| 0.00599| 36| 1.33117| 0.00592
14| 1.33346| 0.00599| 37| 1.33104| 0.00591
15| 1.33339| 0.00599| 38| 1.33090| 0.00591
16| 1.33331| 0.00598| 39| 1.33075| 0.00591
17| 1.33324| 0.00598| 40| 1.33061| 0.00590
18| 1.33316| 0.00598| | |
19| 1.33307| 0.00597| | |
20| 1.33299| 0.00597| | |
21| 1.33290| 0.00597| | |
22| 1.33280| 0.00597| | |
23| 1.33271| 0.00596| | |
24| 1.33261| 0.00596| | |
25| 1.33250| 0.00596| | |
26| 1.33240| 0.00596| | |
27| 1.33229| 0.00595| | |
28| 1.33217| 0.00595| | |
29| 1.33206| 0.00594| | |
30| 1.33194| 0.00594| | |
31| 1.33182| 0.00594| | |
32| 1.33170| 0.00593| | |

Maintenance and cleaning

Always place the dustcover over the refractometer after use. Clean both prism surfaces with a tissue.

Cleaning the optics

• If eyepiece or prism surfaces are poluted, they can be cleaned with a lenspaper with a little alcohol.
• Never use a drop of alcohol directly on the lenses, since it can damage the coating.

Warning

• Cleaning cloths containing plastic fibres can damage the coating of the lenses!

Maintenance of the stand

Dust can be removed with a brush. In case the stand is really dirty the surface can be cleaned with a non-aggressive cleaning product.

Refractometer accessories

• LE.5209: Cold light source EK-0, 12 V 20 W, with single-arm, self-sustaining light guide
• SL.5208: Spare halogen bulb 12 V 20 W for LE.5209
• 98.492: Spare thermometer 0-50°C
• 98.496: Calibrating test piece nD 1.5163
• EUROMEX Microscopen B.V.
• HOLLAND
• www.euromex.com.

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