PTFE is a superb seal material. Approved for food and pharmaceutical use, it is chemically inert and wears exceptionally well since it has a low coefficient of friction and a temperature range from -200 to +250 degreesC.
Rubber has none of those properties, but it does have one real advantage. When compressed it recovers to its original size.
Materials specialist Economos has developed a seal material that combines the benefits of PTFE and rubber. `It is a sort of halfway material,’ says Derek Duncan, sales manager.
The `intelligent’, Flex-o-Form material containing graphite and mineral additives, provides 15% compressibility and a recovered capability of 62% measured to ASTM F36A.
Tests show `considerably less leakage’ against rival seals, even when re-used up to 25 times. A grade for use in fugitive emissions seals is being tested to ingress protection standard IP65.