Thermal radiation shield contains escaping heat from an induction furnace. The shield consists of a sheet of refractory metal foil and a loosely packed mat of refractory metal fibers in a concentric pattern. This shielding technique can be used for high temperature ovens, high temperature fluid lines, and chemical reaction vessels

Ebihara, B. T.

English

NASA Technical Reports Server

June 1965	 Brief 65-10188 
NASA TECH BRIEF	 NA 
NASA Tech Briefs are issued by the Technology Utilization Division to summarize specific 
technical innovations derived from the space program. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia, 22151. 
Refractory Metal Shielding (Insulation) Increases Operating Range

of Induction Furnace
-1 Shield 
Metal Fiber 
Spacer 
ding Wire 
The problem: The operating range of an induction 
furnace is partially determined by the degree to which 
escaping heat, in the form of radiation, can be con-
tained. Ceramic oxide refractory materials insulate 
well to 3000°F. Multiple shielding with a composite 
of refractory metal and ceramic oxide is effective to 
about 4500'F but the ceramic component is suscepti-
ble to thermal shock and crystalline instability above 
that level. Effective thermal shielding is needed to 
operate induction furnaces at temperatures above 
5500°F. 
The solution: A thermal radiation shield consisting, 
alternately, of a sheet of refractory metal foil and a 
loosely packed mat of refractory metal fibers in a con-
centric pattern. This shielding contains the radiation
from the furnace until it approaches the melting tem-
perature of the shielding material. 
How it's done: Tungsten foil is alternated with a 
tungsten spacer. This spacer may be in the form of a 
loosely packed fibrous mat, fiber felt sheet, woven 
wire mesh, or corrugated foil. The foil and spacer lam-
ination is then wound about the furnace to the desired 
thickness. The shielding is then banded on the outside 
with tungsten wire. 
Notes: 
1. This shielding is compact, lightweight, and simple 
to fabricate and, because of its low mass density, 
exhibits little thermal inertia, thereby permitting 
more rapid thermal cycling.
(continued overleaf) Af
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
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=19650000186 2020-03-11T17:24:21+00:00Z
2. A tungsten foil-tungsten fiber mat composite was 
tested on a vacuum induction furnace and a tem-
perature of 5850'F was reached. Tungsten melts 
at approximately 6100° F. 
3. This shielding technique should be of interest to 
manufacturers and users of high temperature 
ovens, high temperature fluid lines, chemical reac-
tion vessels, etc. 
4. inquiries concerning this invention may be directed 
to:
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio, 44135 
Reference: B65-10188
Patent status: NASA encourages the immediate 
commercial use of this invention. It is owned by 
NASA and inquiries about obtaining royalty-free 
rights for its commercial use may be made to NASA, 
Code AGP, Washington, D.C., 20546. 
Source: Ben T. Ebihara 
(Lewis-202) 
A 
Brief 65-10188	 Category No. 02


Refractory metal shielding /insulation/ increases operating range of induction furnace

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server