polarization filters which enable detection of foreign bodies by
making them clearly visible
in the dark area.
The testing device consists of the light housing (1) with 3
fluorescent lamps (2) and the light
scattering opal glass plate (3). As the polarization filters used
should not be overheated, reaching
temperature of more than 70°C
during uninterrupted use if possible, the filter (4) is fastened
in front of the light housing by means of an insulation ring. The
second filter (5) which is held in a metallic mount (6) being
right in front of the magnifying lens (7) permitting twofold
magnification, renders it possible that a rotary motion of 90
degrees is being realized out of the polarization
plane. Frame (6) is adjustable in the longitudinal direction for
the purpose of focussing what is intended to be magnified. Testing
of the filled white bottles shall be carried out in a room not
being too bright, if possible. Prior to the latter the
polarization filter (5) needs being adjusted by means
buttons (8) to the maximum polarization degree, i. e. to the
almost entire darkening of the visiual field. If there are foreign
bodies in the bottles positioned between both filters, they are
illuminated in the polarized light and are very clearly visible.
The bottles are supported by two axes and are turnable by means of
3 rollers (9) each. The method of testing does not overstrain the
eyes of the operator so that even over long periods no signs of
tiredness arise. Both filters have a diameter of 250 mm, the
magnifying lens is 300 mm in diameter. For brown bottles a cold
light device can be installed, for which an extra price is charged.
One year. This warranty does not cover any faults and / or
to improper handling.