a) To test transparent and translucent liquids
!
Drop the tested liquid onto prism surface using a dropping tube. Cover the incident
prism and lock with the knob (1.10). The sample must be homogeneous and spread prism
surface wide without bubbles.
!
Open the shield (1.9) and check the reflecting mirror (1.1) is closed, then adjust the ocu-
lar (1.1) based on the dioptric correction required until you see the crossed lines sharply.
!
Turning the refraction index adjustment knob (1.5) look for light and dark field divisory
line, then turn knob (1.4) to adjust the dispersion in a way this line is seen without any colour
and as clear as posible. Once you have done this, turn the knob (1.5) again to move divisory
line up to the middle of both crossed lines.
!
The value in the scale tells us the accurate liquid refraction index.
Reading
!
The range of the reading scale is in refractin index from 1.3000 to 1.7000 and from 0 to
95% in Brix degrees.
Example: In this scale we read 1.3355 nD and 12.5º Brix.
b) To test transparent solids
!
Solid to be measured must be smooth and polished faced.
!
Put one or two drops of naphthalene monobromure on the refraction prism surface.
Clean all the tested object surface properly to get the best contact. Open the illumination
window for solid samples (1.8) and read the value on the scale.
!
When observing through the eyepiece, search for the divisory line between light and dark
coloured fields, and do as the instructions in the previous case.
c) To test translucent solid
!
The object to be measured must be smooth and polished faced.
!
Put one or two drops of naphthalene monobromure on the solid and clean solid surface
to place it on the refracting prism. Open the reflecting mirror (1.8) to solid samples illumina-
tion.
Picture 5
e) Refractive index estimation at different temperatures
!
Insert the thermometer into its socket (1.11), connect the thermostat to the prepared con-
nectors (1.6) for bottom prism and (1.7) for top prism, thanks to the thermostat temperature
can be read in the ranges required. Before each reading, wait a couple of minutes to stable the
temperature.
Page 16
d) To measure sugar concentration in sugary liquids
!
The procedure is similar to liquid samples but the reading can
be done on a Brix scale (larger scale 0- 95%) reading directly the
sugar concentration in the liquid.
Instruction manual 50320XXX
Version 2 December-03