[liftbag]

Originalmente inviato da liftbag

Sono questi: Buna o-rings # 003-90D Price for 50 pcs

Mi autoquoto perché della solita misura ho visto solo ora che ci sono anche quelli in Viton, sempre 90 shore di durezza.
In subacquea quelli in Viton sono preferiti perché durano di più, magari sono da preferire a quelli in nitrile, certo costano un botto, 2,50$ per 50 pezzi

Una descrizione presa a caso sugli o-rings in Viton:

Fluorocarbon elastomers have grown to major importance in the seal industry. Due to its wide range of chemical compatibility, temperature range, low compression set, and excellent aging characteristics, fluorocarbon rubber is the most significant single elastomer developed in recent history. Fluorocarbon elastomers are highly fluorinated carbon-based polymers used in applications to resist harsh chemical and ozone attack. The working temperature range is considered to be -26°C to +205°/230°C (-15°F to +400°/440°F). But for short working periods it will take even higher temperatures. Special compounds having improved chemical resistance are also available with new types always being developed. Generally speaking, with increasing fluorine content, resistance to chemical attack is improved while low temperature characteristics are diminished. There are, however, specialty grade fluorocarbons that can provide high fluorine content with low temperature properties.

Fluorocarbon O-rings should be considered for use in aircraft, automobile and other mechanical devices requiring maximum resistance to elevated temperatures and to many fluids. FKM (FPM, Viton®, Fluorel®) resist mineral oils and greases, aliphatic, aromatic and also special chlorinated hydrocarbons, petrol, diesel fuels, silicone oils and greases. It is suitable for high vacuum applications. Many fluorocarbon compounds have a higher than normal mold shrinkage rate, molds for fluorocarbon products are often different from molds for Nitrile.