Flexibler Grafit wird aus natürlich vorkommendem Grafit hergestellt und weist einen Kohlenstoffgehalt von 90% bis 99,9% auf.
Die Grafitflocken werden mit Säure behandelt, neutralisiert und getrocknet. Diese Flocken werden dann hoher Temperatur ausgesetzt. Das darin enthaltene, verdampfende Wasser treibt die Flocken auseinander, sodass sie ein bis zu 200-faches Volumen erreichen. Die expandierten Flocken werden ohne Bindemittel oder anderen Zusatzstoffen kalandriert. Auf diese Art entstehen Platten aus reinem Grafit mit hoher Flexibilität und ausgezeichneter Hitzebeständigkeit.
Dichtungen aus flexiblem Grafit haben ein niedriges Kriechverhalten, welches als bleibende plastische Deformation unter Druck definiert wird. Das bedeutet, dass die Schraubenkräfte während des Betriebes nur geringfügig nachgeben und die Notwendigkeit die Schrauben (Bolzen) nachzuziehen damit weitgehend reduziert wird.
Die wichtigsten Eigenschaften von flexiblem Grafit:
Aufgrund seiner Eigenschaften ist flexibler Grafit eines der zuverlässigsten Dichtungsmaterialien. Es bietet exzellenten Schutz gegen Säuren, Laugen und organischen Verbindungen. Grafit wird jedoch nicht für Anwendungen mit oxidierenden Medien (Sauerstoffträger) bei Temperaturen über 450°C (840°F) empfohlen. Der erhitzte Kohlenstoff reagiert mit Sauerstoff und formt Kohlendioxid (CO2). Daraus resultiert ein Masseverlust der Dichtung und infolgedessen eine Reduzierung der Schraubenkräfte.
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