CV-Series valves use an O-ring fluid seal design that has proven effective with a range of fluids. Viton is the standard O-ring material, but there are many other material options. The most common O-ring materials are listed below:

• Viton (fluorelastomer or FKM): 0°C-200°C, Elastomer. Excellent for oils & most chemicals. Avoid phosphate esters and ketones. This is the standard O-ring material supplied, unless otherwise requested.
• Buna-N (NBR/Nitrile elastomer): several grades available. Continuous use to about 110°C, but HBNR compounds available to 150°C. Good for petroleum oils & fluids, water. Not recommended for ketones (MEK, acetone), strong acids >10% concentration), and halogenated or nitro hydrocarbons.
• UHMW-PE (ultrahigh molecular weight polyethylene – thermoplastic): Self-lubricating (low friction), long-wearing, excellent abrasion & chemical resistance (including petroleum oils, organic alcohols, ketones, and acids). Not recommended for use with highly oxidizing chemicals (eg, bleach) or chlorinated solvents (cause swelling). Maximum operating temperature 82°C.
• AFLAS (TFE/P or FXM elastomer): Excellent chemical resistance to most acids & bases, amines, petroleum oils & fuels, and steam. Good permeation resistance but not as resilient as Viton. Maximum operating temperature 204°C.
• Chemraz/Kalrez (FFKM): Excellent chemical, heat, and explosive decompression resistance. Expensive. Maximum operating temperature 249°C (higher in special formulation).
• Other: Other O-ring materials are available. Please contact Vindum Engineering to discuss.