Double spiral molybdenum heater element uses low current, needs no insulation, and requires support only at the ends, which are also the power input points. Because there is no insulation or internal support necessary, the heater is lightweight. Its temperature potential will vary with its size and environment

Hansen, E. L.

English

NASA Technical Reports Server

July 1968
	 Brief 68-10223 
•2GY C
AEC-NASA TECH BRIEF 
US
AEC-NASA Tech Briefs describe innovations resulting from the research and development program 
of the U.S. AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial 
application. Tech Briefs are published by NASA and may be purchased, at 15 cents each, from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Lightweight Heater Generates High Temperatures from Low Current 
Inner Spiral 
- - - Outer Spiral 
Inner Heat Shield 
Outer Heat Shield 
0^ 
L Glass Support Insulator 
The problem: 
To design a small heater with a high temperature 
capability to operate on low current, and be of simple, 
compact configuration and light in weight. 
The solution: 
A double spiral molybdenum heater element that 
uses low current, needs no insulation, and requires 
support only at the ends, which are also the power 
input points. 
How it's done: 
Two molybdenum spirals are wound with the same 
pitch, but in opposite directions. The spirals are as-
sembled one inside the other and are spot-welded for 
support where they intersect. This eliminates sag in the 
heater. The double spiral heater is the electrical 
equivalent of a single spiral element with strips of the 
same length but twice the width.
Notes: 
I. Because there is no insulation or internal support 
necessary, the heater is lightweight. It is essentially 
rigid so that it could be used in portable equipment 
and appliances or in a confined space. Since it is 
easily sterilized, it can be used in clean rooms and 
sterile environments. Its temperature potential will 
vary with its size and environment. 
2. In development tests, a four- to five-inch long dou-
ble heater in a vacuum generated a temperature of 
1000°C and required a current of only 75 amps. It 
has proven extremely durable. 
3. Inquiries concerning this innovation may be di-
rected to: Sandia Office of Industrial 
Cooperation Org. 3413 
Sandia Corporation 
Post Office Box 5800 
Albuquerque, New Mexico 87115 
Reference: B68-10223
(continued overleaf( 
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Administration. Neither the United States Government nor any per- 	 method, or process disclosed in this document may not infringe pri-
son acting on behalf of the United States Government assumes any vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19680000223 2020-03-12T05:34:12+00:00Z
Patent status: 
No patent action is contemplated by AEC or NASA.

Source: E. L. Hansen

(SAN- 10004)
. 
Brief 68-10223 Category 01


Lightweight heater generates high temperatures from low current

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