Automotive fuel systems harbor the risk of electrostatic charging which may lead to arcing. The objective, therefore, is to engineer fuel systems using conductive components. Parker-Prädifa effectively supports this aim in a new generation of FKM sealing compounds delivering significantly increased conductivity combined with excellent media resistance. Compared with standard FKM materials for fuel applications, the new Parker compound V8918-75 improves conductivity by a factor of 1,100,000 on the component (O-ring).
Conductivity of Sealing Systems Plays a Significant Role
As the FKM elastomers generally used in fuel applications are very good insulators per se, the utilization of standard elastomers would result in an electrical isolation of the fuel system components. Therefore, Parker-Prädifa developed a new generation of FKM sealing compounds with significantly increased conductivity combined with excellent media resistance. Standard FKM compounds for fuel applications have a conductivity of 2.1E+11, whereas the conductivity of Parker’s new FKM compound V8918 is 1.83E+4, equating to an improvement by a factor of 1,100,000.
The development of the new FKM compound generation involved a number of criteria to be observed. The physical properties of the FKM had to be on a high level, electrical conductivity was to be significantly increased, media resistance to fuel, biofuels and flexfuels had to be exceptionally good, and cold flexibility had to be ensured. Table 1 summarizes the properties profile of the newly developed compound V8918.
New Generation Combines Conductivity with Media Resistance
In addition to significantly enhanced conductivity, the utilization of a material in modern fuel systems requires excellent media resistance. Table 2 reflects the storage results of V8918 in FAM B and E85. The storage tests were conducted according to VW 2.8.1 A at 23 °C for 168 hours. After re-drying the samples at 85 °C for 22 hours, only a marginal change of the original properties can be observed in both test media.
A Material for Four Requirements Profiles
The new Parker-Prädifa compound V8918-75 exhibits a well-balanced physical profile, significantly increased electrical conductivity, very good media resistance, as well as very good suitability for low application temperatures. Consequently, it is predestined for sealing solutions to minimize electrical charging in fuel Systems.
Article contributed by
Dr. Heinz-Christian Rost
Technology and Innovation Manager,
Engineered Materials Group