- Author
- Graham, T. L. | Berner, W. E.
- Title
- Development of Seals for Nonflammable Hydraulic Fluids. Final Report.
- Coporate
- Air Force Materials Lab., Wright-Patterson Air Force Base, OH
- Report
- AFML-TR-794143, January 1980, 90 p.
- Distribution
- Available from National Technical Information Service. Limited to US Government agencies only; test and evaluation; September 1979. Other requests for this document must be referred to the Air Force Materials Laboratory (AFML/MBT), Wright-Patterson Air Force Base, OH 45433.
- Keywords
- hydraulic fluids | seals
- Abstract
- This research was initiated to develop elastomeric selas compatible with two candiadate nonflammable aircraft hydraulic fluids (Halocarbon A0-8 and Freon E-6.5) for use over the -53.9 deg. C (275 deg. F) temperature range at system pressures as high as 20.7 MPa (3000 PSIG). These two fluids were selected from the several candidate fluids investigated as the best prospects for developing a suitable formulated nonflammable fluid for use in future aircraft systems. Initial screening tests showed phosphonitrilic fluorinated (PNF) and chlorinated polyethylene (CPE) elastomers to be compatible with the Halocarbon A0-8 fluid. On the bais of preliminary dynamic test resultPNF is considered to be the prime candidate. O-ring seals based on this elastomer exhibited excellent low temperature sealability and moderate leakage at high temperature and maximum pressure when evaluated as both a rod and piston seal. Similar dynamic tests performed on seals based on a CPE compound showed that selals of special design will have to be perfected to meet the low temperature -53.9 deg. C (-65 deg. F) piston seal performance requirement. Elastomers that proved to be compatible with the Freon E-6.5 fluid were: EPR (ethylene propylene rubber), butyl, PNF and hydrofluorocarbon elastomeric polymers. Of the compounds dynamically evaluated which included a spring-energized hydrofluorocarbon jacketed seal, O-ring seals based on an EPR compound exhibited superior performance as a rod and piston seal. Additional compounding seal development work is planned w3ith emphasis on the development of improved PNF-and EPR-based seal compounds.