24
8. Measurement of liquid sample
Turn the color compensator knob to
achromatize the boundary line so as to
get it to appear clearly in the field.
Again turn the measurement knob to
set
the
boundary
line
to
the
intersection of the cross hairs.
While observing through the eyepiece,
gently turn the measurement knob
until the boundary line appears in the
field of refraction view. At that time,
the boundary line may be colored and
unclear
because
it
is
not yet
achromatized.
If
so, turn
the
measurement knob in a wide range so
as to set it at a point where the field of
refraction view cleary changes from
bright field to dark field or vice versa.
The brightness of the field can be
adjusted with the illumination selector
switch in the upper part of the digital
thermometer, which can be set to one
of 8 steps.
c)
d)
The upper scale is for reading
Refractive Index (nD) while the lower
scale is for Brix percent. Since the
minimal graduation unit for Refractive
Index is 0.0002, the scale can be read
at a unit of 0.00005 with the eye. On
the other hand, Brix percent scale is
graduated at a unit of 0.1%, the scale
can be read at a unit of 0.01% with the
eye.
e)
The brightness of the illuminator
lamps can be adjusted using the
brightness adjustment switch on the
upper
surface
of
the digital
thermometer (See page 12).
ͤ
Since measured value for liquid sample
changes depending on change of
temperature, it is advised to use a
circulating constant temperature bath
to
keep
the sample
temperature
constant. If liquid sample is measured
without use of a circulating constant
temperature bath,
read
the
temperature indication to know the
actual measurement temperature and
append it to measured value without
fail.
ە
Caution on measurement of liquid
sample
Fig. 8-2
Fig. 8-3
Lighting hole
