O-rings are a key component in many industrial applications, providing an effective and reliable sealing. These small rings are crucial in preventing leaks and ensuring the proper functioning of various mechanical and hydraulic systems.
What are O-rings?
O-rings are sealing rings with a circular section, usually made of elastomers such as rubber or silicone. Their simple but effective design allows for the creation of a watertight seal between two surfaces. O-rings (O-R), in sealing cases, are the most economical and versatile solution. Thanks to their simple design, they are used in many industrial applications, both static and dynamic. O-rings (O-R) guarantee an excellent sealing and are particularly suitable in all cases where space is limited.
The main variants include:
● Nbr O-ring: Made of nitrile rubber (NBR), they are ideal for applications that require resistance to oils and fuels.
● Viton O-ring: Made of rubber and considered among the most resistant to fluids; viton o-rings are used in numerous industries, including aerospace, automotive, household appliances, chemical and fluid industries.
● Silicone O-ring: Used for their excellent resistance to high temperatures and flexibility even at low temperatures.
O-rings are also available in other materials such as, for example, ffkm, epdm, polyurethane, hnbr, epdm/perox, fep/viton, fep/silicone, neoprene, fluorosilicone, ptfe, sbr, acm, aflas.
O-Ring Applications
O-ring are used in a wide range of industries, from automotive to aerospace, from machine building to appliance manufacturing. Some common applications include:
- Hydraulic and pneumatic systems
- Pumps and compressors
- Air conditioning systems
- Medical equipment
O-Ring Benefits
The use of o-rings offers numerous benefits, including:
- Sealing efficiency. Thanks to their ability to deform under pressure, they create an effective hermetic barrier.
- Material versatility. Available in various materials such as NBR, EPDM, FKM and silicone, gaskets can be selected based on the specific needs of the application.
- Easy replacement. O-rings are easy to install and replace, reducing maintenance time.
Choosing the right O-Ring
When choosing an o-ring, it is essential to consider the material, size and specific application. O-rings must be compatible with the fluids and operating temperatures of the system in which they will be used. For example, rubber o-rings are ideal for general applications, while silicone o-rings are preferable for high-temperature environments. Below is a table that includes the main materials, uses and temperature ranges of o-rings.
| Material |
Use |
Features |
Temperature |
| NBR O-ring |
General machine building, equipment and pumps, hydraulic and pneumatic devices. |
Resistance to oils, mineral and vegetable fats, alkalis, alcohols, gases, water, glycols, salt solutions, foodstuffs; relative resistance to ozone. |
-30 +100 |
| VITON-FPM-FKM |
|
|
|
| Construction of chemical equipment of high vacuum pump, hydraulic equipment with flammable fluids. |
High heat resistance, outstanding resistance to chemicals: oils, aliphatic hydrocarbons, various flammable hydraulic fluids. |
-15 +200 |
|
| SILICONE O-ring |
Construction of chemical equipment and machines for the food industry. |
Wide temperature range; food compatibility; limited abrasion resistance. |
-60 +200 |
| EPDM O-ring |
Plumbing and heating taps, pumps, nuclear equipment. |
Good resistance to hot water and steam, ageing and weathering. Not resistant to mineral oils and greases. |
-40 +160 |
| CR 70 O-ring |
Refrigeration compressors. |
Resistant to weathering and ageing, alkalis, alcohols, grease, glycol, ozone, refrigerants. |
-40 +100 |
| PTFE O-ring |
55 shore d |
Severe duty or aggressive fluids, not reusable for a second use due to low deformability and plasticity, effective sealing ideal for effectiveness with chemicals, solvents and for their longevity, excellent insulation against electrical energy, possess a low coefficient of friction. |
Up to 300°C |
| FEP/FPM FEP/MVQ |
|
|
|
| O-ring |
Pharmaceutical industry, food chemistry. |
Outer capsule o-rings in fep-pfa, mvq-silicone, fpm-viton: recommended for installation in open housings, the outer fep casing guarantees resistance to aggressive media and high temperatures, the inner core guarantees elasticity and plasticity, depending on the application. The inner o-ring can be made of viton or silicone; these o-rings are ideal as an alternative to applications using ffkm o-rings, with lower costs. |
-60 +205 |
| PU O-ring |
Mechanical heavy-duty applications, e.g. hydro-pneumatic breakers, excavators, dynamic loads. |
As an elastomer it guarantees reliability in the event of an abrasion risk, better than nbr, hardly prone to tearing, excellent elasticity and plasticity. Resistance to ozone. Disadvantages: poor resistance to water, glycol, not compatible with acids and alkaline solutions. Not resistant to high temperatures. |
-40°C up to 100°C |
| FFKM O-ring |
High temperature applications. |
Static applications. Fragile and inadequate at low temperatures - 25-30°c. Used in various fields, where there are extreme conditions of high temperatures, pharmaceutical chemicals, food, electronics and other critical applications. Subject to low swelling when in contact with chemicals. |
N896 -15+330°C N894 -20+270°C K4079 -20+316°C |
Conclusion
O-rings are an essential component for effective sealing in many industrial applications. Their versatility, efficiency and ease of use make them a preferred choice for engineers and technicians worldwide. Whether o-rings or other seals, choosing the right material and size is crucial to ensure maximum system performance and durability.
