Thermocouple continuously measures a flowing gas up to 4500 degrees F in a hazardous environment. The thermocouple combines rhenium and tungsten in the probe, housing, and swaged extension lead. The wires extend continuously from the cold junction to the probe tip to eliminate errors from secondary thermocouple effects

Hoff, R. G.

English

NASA Technical Reports Server

March 1966	 Brief 66-10134 
NASA TECH BRIEF
	
Df I 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
High Temperature Thermocouple Operates in Reduction Atmosphere 
Cold Junction Body
/ Beryllium 
Oxide reads Probe Plug 
Probe Tube Probe Leads 
Cable to Instrumentation 
The problem: 
To design an instrument for the continuous meas-
urement of a flowing gas up to 4500°F in a hazardous 
radiation environment. 
The solution: 
A thermocouple that combines tungsten and rhe-
nium in the probe, housing, and swaged extension lead. 
How it's done: 
The probe is made of tungsten-5°-rhenium and 
tungsten-26°-rhenium wire insulated by beryllium
'Blackbody' 
Reference 
oxide beads inside a tungsten-26°,-rhenium tube. The 
sensor junction is formed near the probe tip by a 
tungsten-26°.-rhenium plug that forces the two wires 
against the side of the tube and electrically shorts 
them together. The outer end of the plug is fused to 
form a gastight metallurgical seal as well as a me-
chanical force-fit hold of the plug. A small hole drilled 
part way through the plug serves as a blackbody refer-
ence for use with an optical pyrometer during furnace 
calibration.
(continued overleaf) 
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 owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000133 2020-03-11T17:30:10+00:00Z
Notes: 
1. The thermocouple wires extend continuously with-
out splice or foreign material from the cold junc-
tion to the probe tip, thus eliminating errors from 
secondary thermocouple effects. 
2. This thermocouple operates over a range of 5000 
to 450OF with an accuracy of ±l% at the high 
end and better than ±11% at the low end. 
3. The probe may be used to measure high tempera-
ture gases in a non-oxidizing atmosphere with 
some development, and may be modified for use in 
an oxidizing atmosphere. 
4. Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
AEC-NASA Space Nuclear Propulsion 
Office 
U.S. Atomic Energy Commission• 
Washington, D.C., 20546 
Reference: B66-10134
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C., 20546. 
Source: R. G. Hoff, et al

of Aerojet-General Corporation 
under contract to

Space Nuclear Propulsion Office

(NU-0046) 
Brief 66-10134	 Category 01


High temperature thermocouple operates in reduction atmosphere

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