The Dark Spot optical principle utilized by Michell's Condumax hydrocarbon dew-point
analyzer is radically different from that of any other cooled mirror
instrument. Sensitivity of the order of 1ppm (molar) of condensate enables the
analyzer to detect the almost invisible films of condensate which are
characteristic of hydrocarbon gases at dew point, due to their low surface
tension.
The optical surface is the key element of the sensor cell and
comprises an acid etched, semi-matt surface with a central conical shaped
depression. A well collimated beam of visible red light is focused onto the
central region of the optical surface. In the dry condition most of the
incident light beam is reflected from the optical surface to form an annulus
ring of light. Optical detection is made of light dispersed.
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Condumax II On-Line Condumax II On-Line is a fully
self-contained hydrocarbon dew-point analyzer that uses the proven "Dark...
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As
hydrocarbon condensates form on the optical surface during a measurement cycle
its optical properties are modified the reflected light intensity of the
annulus ring increases and there is a dramatic reduction in the scattered light
intensity within the dark spot region. It is this secondary effect which is
monitored and interpreted. Michell's hydrocarbon dew-point analyzer, Condumax,
and advanced process moisture analyzer, Promet, can be combined to form a
complete solution for natural gas dew-point quality measurement.
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