O-Rings & Bellows (Elastomers)

O-Rings & Bellows

The secondary seal — usually an O-ring — is the part most likely to fail before the seal faces do, because it’s the component in direct, continuous contact with the process fluid rather than just the atmosphere. Getting the elastomer wrong shows up fast: swelling, hardening, or chemical attack, often within weeks rather than years. Mech Seal Engineering supplies O-rings and bellows in six material grades — Nitrile for general water and mild oil duty, FKM (Viton) for broad chemical and high-temperature resistance, Aflas for steam, amines, and H₂S service where FKM breaks down, Teflon (PTFE) for near-universal chemical inertness, and two composite options, FEP and TTV (double PTFE-encapsulated Viton), which wrap a PTFE or FEP jacket around an elastomer core to combine the chemical resistance of fluoropolymer with the flexibility of rubber. Match the grade to your process fluid, not just the temperature — chemical compatibility is usually the deciding factor.

Nitrile (NBR) O-Rings

Nitrile rubber O-rings offer excellent resistance to oils, fuels, and general hydrocarbons, along with good abrasion resistance and a wide working temperature range, making them one of the most widely used secondary sealing materials in mechanical seals. They provide reliable, cost-effective sealing performance across water, mild chemical, and general industrial pump applications where fluid compatibility doesn't demand a specialty elastomer. We supply Nitrile O-rings precision-molded to standard mechanical seal dimensions for direct fitment across our full seal range.

Teflon (PTFE) O-Rings

Chemically inert, near-universal fluid compatibility, wide temperature tolerance.

Resists aggressive acids, caustics, and solvents
Suited where elastomer compatibility runs out
Precision-molded to standard mechanical seal dimensions

Aflas O-Rings

Aflas O-rings combine strong chemical resistance with high-temperature stability, holding up well against steam, amines, and aggressive process chemicals that degrade standard elastomers like NBR or FKM. Their broad compatibility makes them a preferred choice in oilfield, chemical processing, and other demanding environments where both heat and chemical exposure are ongoing concerns. We supply Aflas O-rings precision-molded to standard mechanical seal dimensions for direct fitment across our full seal range.

FFKM O-Rings

Near-universal chemical resistance, extreme temperature tolerance, minimal compression set.

Withstands aggressive acids, solvents, and steam
Suited for critical, high-purity, and semiconductor service
Precision-molded to standard mechanical seal dimensions

TTV O-Rings

TTV (tetrafluoroethylene-propylene) O-rings offer strong resistance to steam, hot water, and amine-based chemicals, along with good compression set resistance across a wide temperature range, making them a dependable alternative where standard FKM struggles with steam exposure. We supply TTV O-rings precision-molded to standard mechanical seal dimensions for direct fitment across our full seal range.

FEP O-Rings

Encapsulated core with FEP outer jacket, broad chemical inertness, smooth non-stick surface.

Combines elastomer core flexibility with PTFE-level chemical resistance
Suited for high-purity and corrosive process fluids
Precision-molded to standard mechanical seal dimensions

FKM (Viton) O-Rings

FKM O-rings offer excellent resistance to oils, fuels, and a broad range of chemicals, along with strong high-temperature stability, making them one of the most versatile secondary sealing materials across industrial mechanical seals. Their durability and wide fluid compatibility make them a common default choice for process, refinery, and general chemical pump applications where Nitrile's temperature or chemical limits fall short. We supply FKM O-rings precision-molded to standard mechanical seal dimensions for direct fitment across our full seal range.