Product Overview

ITEM 35290
Model REF401
Hand Refractometer
1. Zero Adjustment
Put distilled water on the prism; enough to cover the entire prism. Close the cover
plate and rotate the adjusting screw so that the light/dark boundary line (known as the
shadow-line) evens up with the zero line. After the zero adjustment, clean the prism with
soft cloth.
2. Sample Preparation and Reading (Detailed operating instructions are included in
box)
To take a reading, place a few drops of a sample liquid on the measurement prism.
Ensure that enough solution is added to the prism in order to cover the entire prism.
Close the prism so that the liquid spreads across the entire surface of the prism without
air bubbles or dry spots. Allow the sample to remain on the prism for approximately 30
seconds.
While holding the instrument under a light source, look through the eyepiece. The
salinity concentration is determined by the intersection of the boundary of the light and
dark fields (known as the shadowline) on the printed scale. The left side of the scale
indicates the specific gravity and the right side parts per thousand. If the scale appears
out of focus, the eyepiece may be adjusted by rotating the knurled portion. The
instrument also features an eye guard to prevent stray light from entering the eyepiece
and causing reflections.
It may be necessary to adjust the position of the light source to maximize the contrast
of the shadow-line. Under normal conditions, optimal contrast is obtained by holding the
instrument underneath and perpendicular to a light source.
Once a reading has been taken, wipe dry with a clean cloth (do not wash or rinse) and
place the instrument in the supplied plastic case. Store the instrument in a safe, dry
environment.
Temperature is the single most important factor influencing refractometer readings and
is one of the largest sources of measurement error. However, this device incorporates
automatic temperature compensation and the concern for temperature fluctuations in
sample liquids is alleviated. When ambient temperature varies from 68°F (20°C),readings
are automatically adjusted to compensate for temperature variance between 50°F to 86°F
(10°C to 30°C).
Model Range Resolution Size
REF 401 ~60°F - ~32°F
1.15 – 1.30 sg
10°F
0.01 sg
27 x 40 x 160mm
Prod. No. Pack Name Bar Code
35290 1 Refractometer 032628-352602
To special order these items, please contact Hercules Customer Service Dept at
800-221-9330 (FAX [phone]) or Email: [e-mail]