System utilizing new type hydrogen sensor has overall detection sensitivity and response speed higher than conventional hot-wire or hot-thermistor detectors. System measures concentrations of from 2 parts per million to 30 percent and is adaptable as leak detector and hazard alarm wherever hydrogen is used

Macintyre, J. R.

Neppel, W. C.

English

NASA Technical Reports Server

W3t—S 
July 1971	 RM. 1313	 Brief 71-10209 
KSC HQS. 
•	
—1—
NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the. Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Sensitive Gaseous Hydrogen Detection System 
An extremely sensitive hydrogen detection system 
can measure the concentration of gaseous hydrogen in 
air to a sensitivity as high as several parts per million. 
The system uses a new type of hydrogen sensor as the 
detecting element, and has an overall detection sensi-
tivity and response speed that are higher than conven-
Digital	 Recorder (Microammeter) 	 Shunt 
Regulated 
Supply 
Voltage
hydrogen bubble chambers, mines, refineries, chemical 
process plants, and aerospace facilities. 
Notes: 
1. Hydrogen concentrations of from 2 parts per mil-
lion to 30% have been measured with this system. 
Decade	 Resistance Box	 Heater 
2tenO:e 7fl 
Detecting 
Element 
To Regulated 
Constant Current 
Source 
tional hot-wire or hot-thermistor types of detectors. 
• The detecting element is a thin-film tungsten oxide 
(W0 3 ) resistor sensitized to hydrogen by the addition 
of very small amounts of platinum. When the sensi-
tized detecting element is maintained at a temperature 
in the range of 523 K to 673 K (250° to 400° C), its 
electrical resistance (which is inversely proportional 
to the microammeter reading) varies by a factor as 
large as 10 6 to 1 in response to corresponding varia-
tions in the ambient hydrogen concentration. Because 
the detector is a rugged thin-film resistor requiring 
only. simple electronic circuitry, the system can be 
conveniently and economically employed throughout 
a given installation. 
The system can be adapted to serve as a leak de-
tector and hydrogen-concentration hazard alarm 
wherever hydrogen is used; i.e., in industrial processes,
The following documentation may be obtained 
from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: 
NASA-CR- 10268 (N70-25297), Gaseous Hy-
drogen Detection System 
Patent status: 
No patent action is contemplated by NASA. 
Source: J. R. Macintyre and W. C. Neppel of

General Electric Co.

under contract to

Marshall Space Flight Center

(MFS-2116 1) 
An	 Category 04,01 
This document was prepared under the sponsorship of the National. 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	
will be free from privately ownedrights.
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Sensitive gaseous hydrogen detection system

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