O-Rings elastomeric

Another factor to be considered is the time required to fabricate additional liners if the initial supply is depleted. Recently, General Atomics claimed it was able to fabricate 20-mil thick liners of the required diameter for the reactor. General Atomics plans to float a precious-metal liner in a cylindrical Hastelloy pressure vessel and use cooled elastomeric O-rings that have performed satisfactorily on other SCWO systems to form the SCWO reactor. The annular space between the liner and the vessel wall will be monitored for leaks to indicate when change-out of the liner is required. No decision has been made yet on whether to use platinum or Pt-20%Ir. Because they have markedly different mechanical properties, these two liner materials may require significantly different fabrication methods. Platinum is relatively weak and very ductile Pt-20%Ir is less ductile but 10 times stronger. Final selection of the liner material for use at the NECDF was scheduled for early 2000. Fabrication... 

Compatibility and Corrosion. Gas turbine fuels must be compatible with the elastomeric materials and metals used in fuel systems. Elastomers are used for O-rings, seals, and hoses as well as pump parts and tank coatings. Polymers tend to swell and to improve their sealing abiUty when in contact with aromatics, but degree of swell is a function of both elastomer-type and aromatic molecular weight. Rubbers can also be attacked by peroxides that form in fuels that are not properly inhibited (see Elastomers, synthetic Rubber, natural). 

Material of construction - Almost all elastomeric compounds are available in the o-ring configuration. 

Vacuum Service - The o-ring is the only common popular elastomeric form that seals in both directions. 

MAJOR APPLICATIONS Used to mold equipment parts, seals, and gaskets, particularly in chemical process equipment and in cryogenic systems. Also used as barrier packaging in pharmaceutical industry. Elastomeric homo- and copolymers used in o-rings, gaskets, and diaphragms. 

Large quantities of elastomeric materials are used to produce a m)uiad of products such as hoses, cable insulation, O-rings, seals and gaskets, belting, vibration mounts, flexible couplings, expansion joints, automotive and airplane parts, electrical parts and accessories. With such a wide variety of applications requiring very diverse properties, it is essential that an... 

NACE Test Method for Evaluating Elcistomeric Materials in Sour Gas Environments (TM0187) measures the ability of elastomeric matericds to withstand static exposure to elevated pressure and vapor phase sour gets environments. It is designed for testing O-rings or sheet specimens of el2is-tomeric vulcanites. 

In elastomeric compositions R and R are mixed substituent fluoroalkoxy groups. The current technological applications depend on the oil resistance and nonflammability of these elastomers low T/s are also important. Gaskets, fuel lines, and O-rings are made from this class of elastomer. 

---