Vacuum chamber is remotely sealed by a design using metal seal blades which are inserted into a molten eutectic metal by pressurizing an expansion bellows. The process increases allowable manipulations by improving working space and safety factors

Cordova, R.

Sacoane, G. H.

English

NASA Technical Reports Server

BelIc 
Top Trou 
Heaters 
Chamber
Buffer Zone 
ii Blades 
tectic Metal 
April 1967
	
Brief 67-10059 
.	
AEC-NASA TECH BRIEF 
TES
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. 
Vacuum Chamber Is Remotely Sealed by Eutectic Metal 
The problem: 
To devise a method of sealing a vacuum chamber 
remotely. The final seal could be made only after the 
chamber body was positioned below a fixed top. 
Working space and safety factors minimized the 
allowable manipulations for effecting a practical 
vacuum seal. Moreover, the process had to be easily 
reversible. 
The solution: 
A design that uses metal seal blades which are 
inserted into a molten eutectic metal by pressurizing 
an expansion bellows. 
How it's done: 
The vacuum chamber is provided with a trough that 
contains a eutectic metal. In the bottom of the trough, 
electrical heaters are provided to melt the eutectic.
The seal blades are attached to the bellows, which, in 
turn, are attached to the fixed top section. The cham-
ber is remotely positioned directly under the top and 
the seal blades are lowered into the molten eutectic 
by pressurizing the bellows with nitrogen. Upon 
solidification of the eutectic metal, the seal is com-
pleted. Opening the chamber requires reheating the 
eutectic and removal of bellows gas pressure (with 
possible small amount of vacuum applied to bellows 
to insure retraction). 
Notes: 
I. The space between the sealing plates is pressurized 
with nitrogen to prevent atmospheric air from 
entering the vacuum chamber. 
2. The eutectic metal is an alloy of 45% lead with 55% 
bismuth with a meltin g temperature of 255° F. 
-.	
(continued o' erleaf( 
This document was prepared under the sponsorship of the Atomic 
Energy Commission and/or the National Aeronautics and Space 
Administration. Neither the United States Government nor any per-
son acting on behalf of the United States Government assumes any
liability resulting from the use of the information contained in this 
document, or warrants that the use of any information, apparatus, 
method, or process disclosed in this document may not infringe pri-
vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000059 2020-03-11T20:22:08+00:00Z
3. A vacuum of 52 mm Hg has been achieved with 
this configuration. 
4. Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
AEC—NASA Space Nuclear Propulsion 
Office 
U.S. Atomic Energy Commission 
Washington, D.C. 20545 
Reference: B67-10059
Patent status: 
No patent action is contemplated by AEC or 
NASA.
Source: R. Cordova and G. H. Sacoane
of AETRON Division
Aerojet-General Corporation 
under contract to
AEC—NASA Space Nuclear Propulsion Office
(NU-0091) 
Brief 67-10059	 Category 05


Vacuum chamber is remotely sealed by eutectic metal

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