AS568-261 FFKM O-Ring — 171.04 × 3.53 mm
A robust, high-squeeze section for demanding static and reciprocating seals in larger equipment. With an inside diameter of 171.04 mm and a 3.53 mm cross section, this is a large-bore seal for large-bore machinery and process equipment. Moulded from Aperflu 2275 perfluoroelastomer (FFKM) for continuous service up to 200 °C, this seal resists hot acids, caustics, solvents, fuels and steam.
Dimensions
| Dash number | AS568-261 |
|---|---|
| Inside diameter (ID) | 171.04 mm (6.734 in) |
| Cross section (CS) | 3.53 mm (0.139 in) |
| Outside diameter (OD) | 178.1 mm (7.012 in) |
| Material | Aperflu 2275 perfluoroelastomer (FFKM) |
| Service temperature | up to 200 °C continuous |
Paint, coatings and solvent dispensing
Dispensers, sprayers and quick-connect couplings continuously wetted by solvents and pigments. This FFKM keeps dimensional stability and seal force where solvent resistance is the deciding factor.
Why Aperflu 2275 FFKM
Perfluoroelastomer (FFKM) is the most chemically and thermally resistant elastomer class available — rated for continuous use beyond 200 °C and stable against well over 1,600 chemicals, which is why it is specified where FKM, silicone and EPDM fail.
Typical applications
Hydraulic cylinders, chemical process valves, wellhead and downhole tooling, where Aperflu 2275 outperforms FKM and EPDM in aggressive media and elevated temperature.
Compound properties
| Property | Typical value | Test method |
|---|---|---|
| Hardness | 70 – 71 Shore A | GB/T 39693.4 |
| Tensile strength | 21.2 – 21.8 MPa | GB/T 528 (dumbbell type 2) |
| Elongation at break | 155 – 170 % | GB/T 528 (dumbbell type 2) |
| Compression set, 200 °C × 70 h (25 %, method B) | 15 – 16 % | GB/T 7759.1 |
All values are typical. Every batch is shipped with an individual certificate of analysis and may differ from the typical values listed here.
Chemical resistance
| Media group | Rating |
|---|---|
| Hot organic & inorganic acids | Excellent |
| Caustics (NaOH up to 50 %) | Excellent |
| Ketones, aldehydes, esters, ethers, alcohols | Excellent |
| Solvents, fuels, hydrocarbons, sour gases | Excellent |
| Steam and hot water | Excellent |
| Amines (high temperature, concentrated) | Good – contact us for grade selection |
| Clean-in-place (CIP) / steam-in-place (SIP) agents | Excellent |
| Active pharmaceutical ingredients (APIs) | Excellent |
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