To cool a hot-wire transducer, the two ends of the wire are supported on thermally and electrically conductive rods, surrounded by a fluid cooling medium. By keeping the supporting rods at a substantially constant temperature, the probe is prevented from overheating

Baldwin, L. V.

Sandborn, V. A.

English

NASA Technical Reports Server

Rods 
Probe of 
Resistance Wire 
Particle or 
Energy Beam 
Electrical Connection 
to Probe
June 1964
NASA TECH BRIEF
Brief 63-10344 
This NASA Tech Brief is issued by the Technology Utilization Division to acquaint industry 
with the technical content of an innovation derived from the NASA space program. 
Cooling Method Prolongs Life of Hot-Wire Transducer 
Coolant Out
Coolant In 
The problem: One method of measuring the power 
density of a particle beam, such as from the exhaust 
of an ion rocket engine, in the use of a probe 
(a hot-wire transducer) consisting of very-small-di-
ameter resistance wire, which changes resistance as a 
function of temperature. The heat developed in the 
wire probe by the intercepted portion of the energy 
beam may raise the temperature of the wire above its 
fusing point and thereby destroy it.
The solution: An arrangement for cooling the wire 
probe. 
How it's done: The two ends of the wire are sup-
ported on thermally and electrically conductive rods 
which are surrounded by a fluid cooling medium. In 
this way the supporting rods are kept at a substantially 
constant temperature and prevent the probe from 
overheating. The illustration schematically shows the 
i
n(continued on next page) 
MW
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern-
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or gapresentation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document:
https://ntrs.nasa.gov/search.jsp?R=19630000057 2020-03-11T16:45:32+00:00Z
apparatus with a coolant fluid circulating around the 
conductive rods. 
Notes: 
Instead of using a cooling fluid to control the tem-
perature of the wire, the ends of the conductive 
supporting rods for the probe may be placed in 
intimate contact with metal blocks which serve 
as a heat sink. 
2. The change in resistance of the wire probe due to 
its heating by an energy beam may be measured by 
a conventional constant-current circuit.
3. For further information about this innovation 
inquiries may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B63-10344 
Patent status: NASA encourages the immediate 
commercial use of this invention. It is owned by 
NASA, and a patent application has been filed. When 
patented, royalty-free nonexclusive licenses for its 
commercial use will be available. Inquiries concerning 
license rights should be made to NASA Headquarters, 
Washington, D.C. 20546. 
Source: L. V. Baldwin and V. A. Sandborn 
(Lewis-4 1) 
Brief 63-10344


Cooling method prolongs life of hot-wire transducer

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