Silicone rubber gasket and an alumina gasket retain a vacuum inside a high temperature EMF cell in which higher and lower density liquid metal electrodes are separated by an intermediate density fused salt electrolyte. This innovation is in use on a sodium bismuth regenerable EMF cell in which the fused salts and metals are at about 500 deg to 600 deg C

Hesson, J. C.

English

NASA Technical Reports Server

November 1966 
	
/	 Brief 66-10472 
•	 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. 
Rubber and Alumina Gaskets Retain Vacuum Seal in High Temperature EMF Cell 
Upper Half (Stainless Steel) 
in  
Alumina Gasket 
sulating  
'u•!
001A
 
Insulating Sleew 
Bolt 
­-, 10, C953 PION	 Mfiffiffiff= c=3 INT	 Bolt 
-	 I 
V/A	 Higher
 Silicone Rubber Gasket	 :. Deit Metal	 fj	 Lower Flange 
Lower half (Stainless Steel) 
The problem: 
To retain a vacuum inside a high temperature 
EMF cell in which higher and lower density liquid 
metal electrodes are separated by an intermediate 
density fused salt electrolyte. At the same time, elec-
trical separation between the upper and lower valves 
of the cell should be maintained. Conventional vacuum 
sealing methods cannot be used because either the 
seal fails due to the high temperature or it does not 
electrically insulate the cell halves properly. 
The solution: 
A silicone rubber gasket and an alumina gasket, 
each held between two (lances which extend out from
the edges of the upper and lower halves of the cell. 
The rubber gasket preserves the vacuum seal and the 
alumina gasket electrically separates the two cell 
halves. 
How it's done: 
A heat dissipating flange extends horizontally from 
the bottom edge of the upper cell half, and a similar 
flange extends from the upper edge of the lower 
cell half. An alumina gasket is positioned between 
the upper and lower flanges so that its inner edge 
is close to the inner surfaces of the cell halves. A 
silicone rubber gasket is also placed between the 
flanges, but outside the alumina gasket. Bolts which 
(continued overleal) 
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hold the two cell halves together pass through the 
flanges within insulating sleeves outside the silicone 
rubber gasket position. 
The alumina gasket serves as the liquid seal and at 
the same time electrically separates the upper and 
lower cell halves. The fused salt electrolyte in con-
tact with the alumina gasket may penetrate cracks 
along the edges of the alumina gasket, but such 
penetrations will freeze-seal themselves so that neither 
the electrical insulating effect nor the vacuum seal 
maintained by the silicone rubber gasket is disturbed. 
The silicone rubber gasket is far enough removed 
from the electrolyte so that most of the heat trans-
mitted along the flanges is dissipated to the outside 
atmosphere before it reaches the rubber gasket. 
Notes: 
1. This innovation is in use at Argonne National 
Laboratory on a Na—Bi regenerable EMF cell in 
which the fused salts and metals are at about 
500°-600'C. The device may be heated and 
cooled without damaging the vacuum seal. 
2. This design eliminates expansion problems with 
dissimilar materials. The vacuum holds the two
cell halves together while the alumina gasket 
holds them apart. 
3. Inquiries concerning this innovation may be di-
rected to: 
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 S. Cass Avenue 
Argonne, Illinois 60439 
Reference: B66-10472 
Patent status: 
Inquiries about obtaining rights for commercial use 
of this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 S. Cass Avenue 
Argonne, Illinois 60439 
Source: J. C. Hesson
Chemical Engineering Division
(ARG-17) 
Brief 66-10472	 Category 05


Rubber and alumina gaskets retain vacuum seal in high temperature EMF cell

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