Heat and corrosion resistant preheater elements are used in oxide induction furnaces to raise the temperature to the level for conducting electricity. These preheater elements are then removed and the induction coil energized

Leipold, M. H.

English

NASA Technical Reports Server

nurJ 1964
NASA TECH BRIEF
Brief 63-10193 
This NASA Technical Brief is issued by the Office of Technology Utilization to acquaint 
industry with the technical content of an innovation derived from the NASA space program. 
Removable Preheater Elements Improve Oxide Induction Furnace 
Induction Coil
Oxide Susceptor 
Elements 
Support for 
Preheater Elements 
S
The problem: Preheating the oxide susceptor ele-
ments in an induction furnace to conducting tempera-
ture. Preheating by ordinary resistive elements has 
the advantages of simplicity and controllability, but 
resistive elements corrode or melt at elevated induc-
tion furnace operating temperatures. 
The solution: Resistive preheater elements that can 
be easily withdrawn after raising the oxide susceptor 
elements to conducting temperature. 
. 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 representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
How it's done: An oxide induction furnace is con-
structed with two small holes in its base. Resistive 
preheater elements are mounted on a support so that 
the elements can be inserted or removed from the fur-
nace. An induction coil carrying high frequency cur-
rent is mounted on the outside of the furnace. 
To operate the furnace, the preheater elements are 
put in place and begin heating the oxide susceptor 
elements to the temperature at which they conduct 
(continued on next page) 
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=19630000019 2020-03-11T16:44:52+00:00Z
electricity. The preheater elements are then removed 
and the induction coil, energized. This activates the 
oxide rings which heat the furnace to the desired tem-
perature. Because the preheater elements can be re-
moved they solve the problems of melting and corro-
sion yet present no difficult operational problems. 
Notes: 
Induction furnaces are employed in the hardening 
of many machine parts including gears, hinge pins, 
shafts and guide rails as well as continuous annealing
of steel strip and the reheating of tin plate strip for tin 
reflowing. This method offers the advantages of quick 
heating, less oxidation, less loss of metal, better die 
life and better control of forging temperature. 
Patent status: NASA encourages commercial use 
of this innovation. No patent action is contemplated. 
Source: Martin H. Leipold 
Jet Propulsion Laboratory (JPL-288)
.10 
Brief 63-10193
	
.


Removable preheater elements improve oxide induction furnace

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server