O-rings for NW/KF centering ring, viton
O-rings for NW/KF centering ring, viton
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Depending on the pressure on the O-ring, environment and service temperature, O-rings need to be renewed to ensure leak-free seals. Use the O-rings to service the NW/KF connections on your vacuum systems.
Viton is well known for its excellent resistance to heat and to aggressive fuels and chemicals. Used for high vacuum applications, temperature range from -54°C to 250°C. Viton is a registered trademark of DuPont Performance Elastomers.
Silicone is a popular O-Ring material that is commonly red in colour and is used for chemical applications. Made of elastomeric materials made from silicone, oxygen, hydrogen and carbon. Excellent material for static service at extreme (hot or cold) temperatures. Outstanding flex and fatigue life. Very good for ozone and UV radiation as well as for resistance to fungal and biological attack. Limitations: Avoid chlorinated solvents, aliphatic and aromatic hydrocarbons and petroleum oils. Silicones are generally very permeable to gases and have poor physical strength and abrasion resistance. Temperature Range from -85°C to 232°C. LPCVD/Oxidation, Dry Etch, Resist Stripping.
Buna-N, also known as Standard Nitrile, is used for non-critical and low vacuum applications, temperature range from -54°C to 150°C. Excellent resistance to petroleum-based oils and fuels, water and alcohol. Nitrile also has good resistance to acids and bases, except those with a strong oxidising effect. Limitations: Avoid highly polar solvents (Acetone, MEK, etc.) and direct exposure to ozone and sunlight.
Size | ID [B] | OD | Thickness [A] |
KF16 | 18.5mm | 29mm | 5mm |
KF25 | 28.5mm | 37mm | 5mm |
KF40 | 41.5mm | 50mm | 5mm |
KF50 | 55mm | 65mm | 5mm |
O-ring Materials Comparison Table | |||
Property | Buna-N | Viton ; | Silicone |
Common Name | Nitrile | Fluor Elastomere | Silicone Rubber |
Tear Resistance | Good | Good | Good |
Abrasive Resistance | Good | Good | Poor |
Ozone Resistance | Poor | Excellent | Excellent |
Weather Resistance | Fair | Excellent | Excellent |
Heat Resistance | Fair | Excellent | Excellent |
Chemical Resistance | Fair | Excellent | Good |
Oil Resistance | Poor | Excellent | Poor |
Acid Resistance |
Fair |
Excellent |
Good |
Alkali Resistance |
Good |
Good |
Fair |
Steam Resistance |
Fair |
Fair |
Poor |
Minimum Usable Temperature |
-54°C |
-54°C |
-85°C |
Maximum Usable Temperature |
150°C |
260°C |
232°C |
Color |
Black |
Black / Brown |
Red |
Impermeability |
Fair |
Good |
Poor |
Tensile Strength |
Good |
Good |
Poor |
Cost |
Low |
High |
Medium |
Images are illustrative only. Please check product details before ordering.