The
Automatic Filter Analysis System of JOMESA:
Cleanliness
Analysis,
Measurement
Process,
The patented Metal-Nonmetal recognition, Evaluation
Samples,
Oil
Cleanliness
JOMESA HFD: Metal-Nonmetal Recognition |
Metallic particles:
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When analyzing the
residue particles on a filtermembrane, the detection of metallic
particles is of outstanding importance.
JOMESA recognized very
early (2006) the significance of metal detection and developed a
system based on polarized light, which was quickly accepted as a
patent.
JOMESA uses polarized light to illuminate the filter.
LED ringlight |
LED ringlight with linear polarization attached |
Ringlight, polarization with driving belt |
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Usual light sources emit non polarized light. The light contains all oscillation directions. |
By passing through a linear polarizing foil the light will be linear polarized. |
JOMESA automated polarization system |
The
human eye is incapable of recognizing polarization.
Samples
illuminated with polarized and unpolarized light look the same.
The way how metal and nonmetal particle scatter polarized light is the key of metal-nonmetal detection |
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Metal surfaces reflect the incident light, like mirrors. Incident and reflected light have the same oscillation direction. |
Nonmetal
substances modify or disturb the incident light direction
(mostly because light can intrude into the material), |
What happens if the scattered light enters a second polarization device ? |
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Polarized light can go through polarizers which have the same direction. |
When polarized light and grate have orthogonal orientation, light cannot pass the polarizer. |
Unpolarized light can pass any polarizer (with diminshed intensity) |
JOMESA has harnessed this physical effect in an automated and
patented system since 2006.
Pictures of the particles,
illuminated with polarized light, recorded in two polarization
situations are compared and then
used to discriminate between
metallic and nonmetallic particles.
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Metal with parallel polarizer |
Metal with orthogonal polarizer |
Nonmetal with parallel polarizer |
Nonmetal with orthogonal polarizer |
Comparison of images
(parallel polarisator position versus orthogonal polarizer
postion):
Reflexion in orthogonal polarizer position gets
black ---------------------> It is a metal.
Reflexion in
orthogonal polarizer position gets some sort of grey ---> It is
a nonmetal