An O-ring is a simple sealing element, but its service life depends primarily on selecting the correct material. The temperature ranges below are indicative; final selection must consider the medium, pressure, motion, hardness and exposure time.
The stated ranges are typical values. A specific compound may have different permissible limits.
A widely used material for mineral oils, fuels, lubricants, water and standard hydraulic applications. Good mechanical resistance and cost efficiency.
An enhanced NBR grade for higher temperatures, mechanical loads and more demanding operating conditions.
Material for hot water, steam, aqueous solutions, glycol-based brake fluids and many acids and alkalis.
A material with high thermal and chemical resistance, used with oils, fuels, hydrocarbons and many process media.
An elastomer with a very wide temperature range and good low-temperature flexibility. Used mainly in static applications.
A premium material combining elastomer flexibility with very high chemical resistance. Used in the most demanding installations.
Fluoropolymer solutions are selected where standard elastomers swell, harden or are attacked by the medium.
PTFE provides very high chemical resistance, low friction and a wide temperature range. However, it has limited elasticity, so it requires a suitable groove design and careful installation.
An encapsulated O-ring combines the resilience of a silicone or FKM core with the chemical resistance of a thin, seamless FEP or PFA envelope. The envelope isolates the elastomer from the medium, while the core provides sealing contact pressure.
The information below was prepared from the supplied Vulcan Chem-Ring catalogue.
Chemical and corrosion resistance, a wide temperature range, smooth self-lubricating surface, low friction and reduced product adhesion.
Pumps, valves, filters, pressure vessels, heat exchangers, autoclaves, process installations and vessel covers.
Surfaces must be smooth and free of sharp edges. The ring should not be bent sharply or twisted; suitable lubricant and gentle heating can facilitate installation.
Cryo-Ring™ is designed for very low temperatures, including liquid oxygen and hydrogen installations. Instead of a conventional elastomer core, it uses a helical spring made from 302 stainless steel enclosed in a chemically resistant FEP or PFA envelope.
The seamless FEP or PFA envelope protects the metal core from the medium, while the 302 stainless-steel helical spring maintains constant contact pressure on the sealing surfaces.
FEP: from -250 to +205°C.
PFA: from -250 to +260°C.
Transport and storage of liquefied gases, food, pharmaceutical and chemical industries, and other installations requiring cryogenic capability.
For applications above 100 bar, vent holes should be provided in the encapsulation. They reduce the risk of envelope rupture caused by differential pressure.
| Cross-section | Cross-section tolerance |
|---|---|
| 1,78 | -0,08 / +0,12 |
| 2,62 | -0,08 / +0,12 |
| 3,53 | -0,08 / +0,15 |
| 5,33 | -0,13 / +0,20 |
| 6,99 | -0,15 / +0,23 |
| 8,00 | -0,16 / +0,24 |
| Inside diameter | Tolerance ± |
|---|---|
| 12,71–25,40 | 0,25 |
| 25,41–38,10 | 0,30 |
| 38,11–50,80 | 0,45 |
| 50,81–63,50 | 0,55 |
| 63,51–88,90 | 0,61 |
| 88,91–101,60 | 0,71 |
| 101,61–127,00 | 0,79 |
| 127,01–152,40 | 0,94 |
| 152,41–177,80 | 1,02 |
| from 177.81 | 0,50% |
