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Lightweight, Low-CTE Tubes Made From Biaxially Oriented LCPsTubes made from biaxially oriented liquid-crystal polymers (LCPs) have been developed for use as penetrations on cryogenic tanks. ( Penetrations in this context denotes feed lines, vent lines, and sensor tubes, all of which contribute to the undesired conduction of heat into the tanks.) In comparison with corresponding prior cryogenic-tank penetrations made from stainless steels and nickel alloys, the LCP penetrations offer advantages of less weight and less thermal conduction. An additional major advantage of LCP components is that one can tailor their coefficients of thermal expansion (CTEs). The estimated cost of continuous production of LCP tubes of typical sizes is about $1.27/ft ($4.17/m) [based on 1998 prices]. LCP tubes that are compatible with liquid oxygen and that feature tailored biaxial molecular orientation and quasi-isotropic properties (including quasi-isotropic CTE) have been fabricated by a combination of proprietary and patented techniques that involve the use of counterrotating dies (CRDs). Tailoring of the angle of molecular orientation is what makes it possible to tailor the CTE over a wide range to match the CTEs of adjacent penetrations of other tank components; this, in turn, makes it possible to minimize differential-thermal expansion stresses that arise during thermal cycling. The fabrication of biaxially oriented LCP tubes by use of CRDs is not new in itself. The novelty of the present development lies in tailoring the orientations and thus the CTEs and other mechanical properties of the LCPs for the intended cryogenic applications and in modifications of the CRDs for this purpose. The LCP tubes and the 304-stainless-steel tubes that the LCP tubes were intended to supplant were tested with respect to burst strength, permeability, thermal conductivity, and CTE.
Document ID
20110020354
Acquisition Source
Glenn Research Center
Document Type
Other - NASA Tech Brief
External Source(s)
http://www.techbriefs.com/component/content/392?task=view
Authors
Rubin, Leslie (Foster-Miller Technologies, Inc. Albany, NY, United States)
Federico, Frank (Foster-Miller Technologies, Inc. Albany, NY, United States)
Formato, Richard (Foster-Miller Technologies, Inc. Albany, NY, United States)
Larouco, John (Foster-Miller Technologies, Inc. Albany, NY, United States)
Slager, William (Foster-Miller Technologies, Inc. Albany, NY, United States)
Date Acquired
August 25, 2013
Publication Date
November 1, 2004
Publication Information
Publication: NASA Tech Briefs, November 2004
Subject Category
Man/System Technology And Life Support
Report/Patent Number
LEW-16780
Distribution Limits
Public
Copyright
Public Use Permitted.

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IDRelationTitle20110020330Collected WorksNASA Tech Briefs, November 2004
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