Real-time alkali monitoring system

Patent · Mon Jan 01 04:00:00 EST 1990

OSTI ID:867255

Goff, David R ^[1]; Romanosky, Robert R ^[2]; Hensel, Peter ^[3]

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1. Christiansburg, VA
2. Prosperity, PA
3. Morgantown, WV

A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium emission line, may be detected in the presence of interfering background radiation. A combustion flame is fed by a diverted portion of a process stream and the common end of a bifurcated or quadfurcated fiber optic light guide is adapted to collect light from the flame. The light is guided through the branches of the fiber optic cable to bandpass filters, one of which is adapted to each of the branches of the fiber optic light guide. The bandpass filters are centered at wavelengths corresponding to the emission lines to be detected and two separate filters are required for each species being detected. The first filter has a bandwidth of about 3 nms and the second filter has a bandwidth of about 10 nms. Light detectors are located to view the light passing through the bandpass filters and amplifiers are connected to receive signals from the light detectors. The amplifier corresponding to the bandpass filter having the narrower bandwidth is preset to scale the signal by a factor equal to the ratio of the wide and narrow bandwidths of the bandpass filters. This scaling produces a scaled signal from which the difference between the scaled signal on the other signal can be calculated to produce a signal having an amplitude directly proportional to the concentration of the species of interest and independent of background radiation.

• Research Organization: National Energy Technology Laboratory, Pittsburgh, PA, and Morgantown, WV
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4896965
• OSTI ID: 867255
• Country of Publication: United States
• Language: English

Related Subjects

/356/250/
10
adapted
alkali
alkali monitor
amplifier
amplifiers
amplitude
background
background radiation
bandpass
bandpass filter
bandpass filters
bandwidth
bandwidths
based
based optical
bifurcated
branches
cable
calculated
centered
collect
collect light
combustion
common
concentration
connected
corresponding
detected
detectors
difference
directly
directly proportional
diverted
emission
emission line
emission lines
equal
factor
fed
fiber
fiber optic
fiber optics
filter
filters
flame
guide
guided
independent
interfering
light
light detector
light detectors
light guide
light passing
line
line monitoring
lines
located
monitoring
narrow
narrow band
narrow bandwidth
narrower
nms
optic
optic cable
optic light
optical
optical emission
optics
optics based
pass filter
pass filters
passing
portion
presence
preset
process
process stream
produce
produces
proportional
provided
quadfurcated
radiation
ratio
real-time
real-time alkali
receive
receive signal
receive signals
required
scale
scaled
scaling
selected
selected spectral
separate
signal
signals
sodium
species
spectral
spectral emission
stream
view
wavelengths
wide