Westinghouse Secures U.S. Patent On Self-Protecting Sensing Cell Electrodes — Literature Available

The Combustion Control Division of Westinghouse Electric Corporation recently received a U.S.

patent for its self-protecting electrodes in its Hagan, in situ flue gas sensing cell, and has incorporated this feature into the Hagen Model 240 excess oxygen/excess combustibles flue gas analyzer. Previously, patents on the selfprotecting electrodes had been issued in Belgium, Canada, and the U.K.

This self-protecting feature establishes the Hagan analyzer as a highly reliable flue gas sensor. It is said to be particularly effective in combustion processes that experience reducing stack gas atmospheres containing sulfur.

Low excess air firing or fuel-rich conditions cause sulfur in the fuel to combine with platinum electrodes within the in situ sensor to form platinum sulfide, resulting in serious electrode deterioration. This condition presented problems to the traditional in situ excess oxygen analyzer in the past, particularly in those applications with reducing or high sulfur flue gas atmospheres. This patented self- Load-deflection curve of closed cell flexible foam. protection feature of the Hagan excess oxygen/excess combustibles analyzer is an outgrowth of the successful model 218 and model 225 probe type analyzers. Westinghouse established the model 218 analyzer as the first in situ zirconium oxide excess oxygen sensor in 1971.

Just as in the traditional zirconium oxide excess oxygen analyzer, the new excess oxygen/excess combustibles analyzer requires no sample system, no sample probes, no scrubbers or pumps, and is suitable in flue gas temperatures ranging as high as 1,400 F (760 C). The sensor has a field-replaceable cell, with low installation and maintenance costs.

For further data and free literature on the new electrodes,

sensor service control maintenance corporation experience field effective