Endpoint and/or back diffusion gas impurity detector, and method

Details Endpoint and/or back diffusion gas impurity detector, and method Endpoint and/or back diffusion gas impurity detector, and method

1992-06-12

1993-11-09

Nelms, David C.

Radiant energy

Photocells; circuits and apparatus

Optical or pre-photocell system

340540, G01N 1506

Patent

active

052605850

ABSTRACT:
An endpoint detector for gas purifiers which contains a detection element comprising a small amount of a highly reactive metal coated on an insulator and exposed to the gas stream being purified. This metal does not react with the gas being purified, but does undergo reaction with the impurity species. As this metal reacts with impurities in the gas stream, its conductivity decreases. The change in conductivity signals that the wave front of impurity-containing gas has reached the sensor, and thus the purifier has reached the end of its useful life. The use of a thin coating of reactive metal as the detection element gives the sensitivity that is required to sense sub-part-per-million levels of impurities. This resistance change sensor may be combined with a thermal measurement to detect the presence of exothermic conditions indicative of a large pulse of impurity gas.

REFERENCES:
patent: 3924219 (1975-12-01), Braun
patent: 4603148 (1986-07-01), Tom
patent: 4604270 (1986-08-01), Tom
patent: 4659552 (1987-04-01), Tom
patent: 4723967 (1988-02-01), Tom
patent: 4738693 (1988-04-01), Tom
patent: 4761395 (1988-08-01), Tom
patent: 4781900 (1988-11-01), Tom et al.
patent: 4782226 (1988-11-01), Jeffries et al.
patent: 4797227 (1989-01-01), Tom et al.
patent: 4800189 (1989-01-01), Eschwey et al.
patent: 4847594 (1989-07-01), Stetter
patent: 4853148 (1989-08-01), Tom et al.
patent: 4865822 (1989-09-01), Tom et al.
patent: 4925646 (1990-05-01), Tom et al.
patent: 4950419 (1990-08-01), Tom et al.
patent: 4983363 (1991-01-01), Tom et al.
patent: 5015411 (1991-05-01), Tom et al.
R. C. West, ed., CRC Handbook of Chemistry and Physics, 65th ed., CRC Press, Boca Raton, Fla., pp. D155-D159 (1984).
"Chlorination of silanes by silver chloride," Vanderwielen, A. J., Ring, M. A., Inorg. Chem. 11(2), pp. 246-250 (1972).
"Halogenation of silanes by silver chloride and silver bromide," Hollandsworth, R. P., et al., Inorg. Chem. 6(4), pp. 844-845 (1967).

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