The O-ring represents a gasket made of elastomeric materials selected from various types of Nitrile and Fluorinated rubbers.
For this type of gasket the hardness is different according to their use.
More precisely, the O-rings of the seats with soft seal always require a hardness of 98 SH, while for O-rings to be mounted in the back seat the hardness is between 75 SH and 90 SH.
All O-rings are resistant to explosive decompression and are therefore provided in AED (Anti Explosive Decompression).
Therefore, the most widely used elastomeric materials are chosen by evaluating the valve requirements in terms of pressure, fluid or gas flow rate, operating temperature:
- HNBR AED indicated for operating temperatures of approximately -35°+160° – can be produced from a type resistant from -55° to +160°/180° but can be produced with a hardness of 90 SH.
- FKM / Viton A AED – FKM / Viton B AED – FKM / Viton GLT AED – FKM / Viton GF AED for temperatures from -25°/ 37° to + 23 °/25 ° – TFE / P AFLAS AED fluorinated rubber a new generation that resists up to 200 °/230 ° with excellent chemical resistance.