Fig. 4-1
Fig. 4-2
4. Name and functions of main parts
(1) Main unit of NAR-2T (Figs. 4-1, 4-2 and 4-3)
The field of refraction view and the field
of scale view can be observed through
the eyepiece. When the lamp is on, the
field of scale view is brightly and clearly
observed through the eyepiece as shown
in Fig. 7-5 on page 21. In the upper part of
Fig. 7-5, the boundary line to be seen
between bright part and dark part
appears only when the measurement
knob is properly operated with a sample
on the main prism.
a) Eyepiece
When measuring liquid sample, use this
light to illuminate a sample through the
secondary prism. For measuring solid
sample, utilize another light source such
as the natural light or a proper lighting
apparatus.
b) Sample illuminator lamp holder
d)-a, d)-b Prism open/shut handles
When pouring or putting sample on the
main prism, the secondary prism must
be opened in advance. Since the
secondary prism functions to illuminate
the sample uniformly, its surface to
contact the sample is frosted to diffuse
the
light
uniformly. The standard
clearance
between
the main
and
secondary prisms is 0.2mm.
e) Secondary prism
10
The main prism is the most important
component
for
measurement.
Pay
careful attention to it neither to get it
damaged nor to get it corroded. A
sample is set on the main prism for
measurement. The frames of both the
main and secondary prisms are made of
stainless steel that has strong corrosion
resistance characteristic.
f) Main prism
a)
d)-b
d)-a
When this handle d)-a is turned to the
front side, the secondary prism is raised
upwards by about 1cm. If the handle d)-b
is turned left side, the secondary prism is
opened because this handle serves as a
lever to move the secondary prism. After
measurement of a high viscous sample,
b)
e)
f)
g)
h)
i)
j)
k)
l)
m)
n)
the secondary prism can be detached
from the main prism smoothly without
unreasonable
force
thanks
to
the
abovementioned function of the handle
d)-a.
c)
j)
c) Sample illuminator lamp arm
Direction and hight of sample illuminator
lamp holder can be adjusted.
