Zeolitic molecular sieves prolong the lives of cryogenic engines by preventing contamination of the thermal regenerators on the cold ends of closed-cycle engines. Sieves also serve as thermal insulators by preventing conduction of heat along regenerators through contiguous disks of mesh

Gasser, M. G.

English

NASA Technical Reports Server

October 1970	 Brief 70-10424 
0	
- NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U .S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Molecular Sieves Control Contamination and Insulate

in Thermal Regenerators: A Concept 
Incorporation of zeolitic molecular sieves prolongs 
the lives of cryogenic engines (for development of 
cryogenic temperatures) by preventing contamination 
Cryogenic Cooling
Platform 
Stacked Wire Mesh Disks 
Compressed Molecular-

Sieve Ring 
Compressed Molecular-

Sieve Disk 
Thermal- Insulation 
Sleeve Containing 
Molecular Sieve 
Seal Ring
Porous Metal Container
for Molecular-Sieve Pellets 
Connecting
	 Stainless-Steel 
Rod
	
Pressure-Containment Tube 
Ambient-Temperature Crankcase 
of the thermal regenerators on the cold ends of closed-
cycle engines. Regenerators are composed of stacks
of disks of fine wire mesh, usually of copper; con-
taminants reaching the disks condense and form ther-
mally insulating films. Sieves also serve as thermal 
insulators by preventing conduction of heat along 
regenerators through contiguous disks of mesh. 
The figure shows a thermal regenerator with the 
piston of a cold-displacer to produce cryogenic tem-
peratures. The piston reciprocates in relation to the 
pressure-containment tube which is stationary relative 
to the engine. At each end of the regenerator a porous 
metal filter prevents particulate contaminants from 
entering and molecular-sieve material from leaving it. 
In the event that some contaminants pass the molec-
ular sieve and condense on the regenerator's heat-
transfer surface, the engine can be stopped and 
brought to ambient temperature so that the contami-
nants reevaporate and are absorbed by the sieve. 
Bypassing around the heat-transfer surface is reduced 
by the method of fabrication. An imperfect seal be-
tween the pressure casing and the piston permits gas 
containing contaminants to reach the cold end with-
out passing through the regenerator; the molecular 
sieve at the cold end collects these contaminants, and 
the porous metal cap keeps out particulate contami-
nants. 
Such sieves may be incorporated in a sterling type 
cryogenic engine. 
Note: 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Goddard Space Flight center 
Greenbelt, Maryland 20771 
Reference: TSP70-10424 
Copper or 
Brass Cap 
• Porous Metal 
Cap 
Cylinder 
Piston 
Idahk	 coiiliiiticd o' erical) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19700000409 2020-03-17T00:46:23+00:00Z
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546.
Source: M. G. Gasser
Goddard Space Flight Center
(GSC-109 10) 
Brief 70-10424	 Category 07


Molecular sieves control contamination and and insulate in thermal regenerators - A concept

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