Teledyne 275R - Portable turbine generator purge gas analyzer - Manual (Page 5)

TELEDYNE ANALYTICAL INSTRUMENTS
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1.1
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In order to help you make maintenance purging of turbine generators
safer, Teledyne Analytical Instruments has developed the 275R Turbine
Generator Purge Gas Analyzer. During maintenance of hydrogen-cooled
turbine generators, the cooling gas (H
2
) is systematically replaced with
carbon dioxide (CO
2
) and then air. The 275R accurately measures H
2
concentrations during the replacement process by comparing the difference
in thermal conductivities between a sealed reference gas (helium) and the
atmosphere undergoing replacement.
Since air leaks reduce the purity of H
2
used in cooling, which increases
viscosity and reduces heat conduction, the 275R has a H
2
-in-air range in
order to assist in monitoring H
2
and impurity concentrations for optimum
efficiency during normal operations.
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The Model 275R analyzer has three ranges for purge and normal
generator operation, with zero and span potentiometers for each. Each
range also has its own scale on the meter face. Efficient insulation around
the cell block enables quick restarts so that the instrument can be carried
from one generator to the next without a lengthy warm-up period.
Periodic calibration is all the maintenance necessary. Installation is just
a matter of connecting sample inlet and outlet lines. The reference cell is
sealed; thus, no other gas connections are necessary. Electronic tempera-
ture control in the cell block insures optimum accuracy in measurement.