The “Gold Standard” for Low Temp Fuel
Because of their good hydrocarbon compatibility and
unmatched low temperature performance, fluorosilicone O-ring
materials have become the standard seal materials for use in
low temperature fuel quick connect applications.
To meet the needs of multiple applications, Parker has three
different hardnesses of fluorosilicone O-ring materials.
Extreme Low Temperature Performance
Fluorosilicones have long been used for their outstanding low
temperature properties. With a functional temperature range of
-100°F to +350°F (-73°C to +177°C), fluorosilicone rubber has
the thermal stability to accommodate all automotive fuel
applications. This thermal stability comes from the silicone
backbone that forms the base polymer chain.
Outstanding Fuel and Oil Resistance
Fluorosilicone rubber also has fluorinated side chains
branching off of the silicone backbone that give it chemical
compatibility that approaches that of fluorocarbon rubber;
resistance to petroleum-based oils, greases, and fuels is
excellent. Fluorosilicones have become the seal material of
choice for handling gasoline, E85, diesel fuel, biodiesel, and
ULSD at extremely low temperatures.
Good Rebound Resilience
Historically, fluorosilicones have not offered good short-term
rebound resilience. When stretched to fit into a male O-ring
gland, fluorosilicone materials tended to sag rather than snap
back tight against the groove. These new fluorosilicone
compounds exhibit dramatic improvements in this category.
While there are no industry standard test procedures for this
type of test, it can be easily observed. This improvement in
rebound resilience should make automated assembly more
feasible and decrease the incidence of torn O-rings during
Fluorosilicones generally have poor mechanical properties. As
a result, they wear quickly in dynamic applications and are
easy to tear during installation. Fluorosilicones also have poor
gas permeation resistance, and generally will only meet fuel
vapor emissions requirements when used in conjunction with a
low permeation fluorocarbon seal material.