Melt-out method of constructing strong, pressure-tight fluid coolant channels for chambers is accomplished by cementing pins to the surface and by depositing a melt-out material on the surface followed by two layers of epoxy-resin impregnated glass fibers. The structure is heated to melt out the low-melting alloy

Escher, W. J. D.

English

NASA Technical Reports Server

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STEP 4
Alloy Melted Out 
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STEP 5 STEP 6 
June 1964	 Brief 63-10497 
NASA TECH BRIEF 
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. 
Integral Coolant Channels Simply Made by Melt-Out Method 
Metal Pin 
Wall of Vessel
- 
Low-Melting Alloy 
 U IP 
STEP 1	 Second Layer of	 STEP 2 
Epoxy- Impregnated 
Glass Fibers
First Layer of 
Epoxy- Impregnated 
L .1 71JE 
The problem: To devise a simple method of mak-
ing strong, lightweight, pressuretight fluid-coolant 
channels or jackets for maintaining inner-liner wall 
temperatures of pressure vessels, such as rocket thrust 
chambers, within tolerable limits. Methods that have 
been used for constructing jackets for continuous flow 
of coolants include welding or brazing of multiple 
tubes or channelized ribs which are mounted on the 
liner and externally wrapped with wire. These methods 
are costly and time-consuming and require the use of 
relatively heavy materials, which often do not permit 
the desired flexibility in design. 
The solution: A method in which the integral 
coolant channel is built up on the pressure chamber 
liner using a temporary layer of a low-melting alloy 
that is melted out after layers of epoxy-impregnated 
glass fibers are wrapped around the alloy and cured in 
place. Pins bonded to the liner at the beginning of
fabrication rigidly support the glass fiber wall around 
the resulting channel. 
How it's done: A series of pins are cemented to the 
external surface of the liner or heat-transfer wall of 
the chamber. A suitable melt-out material, such as a 
tin-bismuth alloy, which melts at 281 F, is then depos-
ited on the surface to a depth equal to the desired 
height of the coolant passage, leaving the upper ex-
tremities of the pins exposed. Glass fibers (impreg-
nated with an epoxy-resin) are wound around the 
solidified melt-out material to a predetermined thick-
ness, still leaving the upper ends of the pins exposed. 
Push-on-type head clips are fastened to the ends of the 
exposed pins, and the extreme ends of the pins are cut 
off. A second layer of epoxy-resin impregnated glass 
fibers is then wound over the first layer to a specified 
thickness enclosing the pins, the melt-out material, 
and the liner. Finally the structure is heated to melt 
(continued overlent) 
This document was prepared under the sponsorship of the National 
Aeronautics and S pace 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=19630000086 2020-03-11T16:47:26+00:00Z
out the low-melting alloy. The resin impregnant is 
cured to provide a gastight seal either during the 
rn^lff&d operation or a later time. The resulting struc-
ture, providing integral cooling passages between the 
heat-transfer wall of the chamber and inner wall of the 
glass fiber envelope, is relatively strong, lightweight, 
and pressure tight. 
Notes: 
1. This method of fabrication is applicable to many 
types of pressure vessels, including rocket thrust 
chambers, combustion units, jacketed storage 
tanks, and heat exchangers.
For further information about this innovation 
inquiries may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B63-10497 
Patent status: NASA encourages the immediate 
commercial use of this invention. Inquiries about 
obtaining rights for its commercial use may be made 
to NASA Headquarters, Washington, D.C. 20546. 
Source: W. J. D. Escher (M-FS-91) 
Brief 63-10497


Integral coolant channels supply made by melt-out method

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