X Rings and O Rings are both types of mechanical seals that are used to prevent leakage of fluids, gases and other media, in various industrial applications. While both, X rings and O rings are used for the purpose of sealing, they are used for specific conditions, each providing key advantages to another. They are both often made up of elastomers like, Nitrile or Buna-N, Silicone, EPDM, FKM or Viton, FFKM and HNBR – to name a few.
Detailed below are some of the differences between the two, and reasoning for why one should pick a particular type of seal.
X Ring Seals or Quad Rings:
The X rings get their name because the cross-section of the seal resembles the letter ‘X’. It is also commonly known as Quad Rings.
- Sealing Efficiency:
The X ring is a four-lobed design seal that provides multiple sealing surfaces. As a result, in a dynamic application where the seal endures repetitive impact, an X ring or Quad ring may be more beneficial to use because of the multiple sealing surfaces that prevent leakage.
- Prevention of Leakage due to Twisting:
Due to their X shaped cross-section, X rings are less likely to twist under dynamic or sliding applications, offering enhanced stability and sealing performance.
- Reduced Compression Set:
X rings are less prone to compression set due to their X design, which distributes the compressive forces evenly.
- Friction:
The unique shape helps maintain lubrication between the seal and the mating surface, which lowers friction and hence reduces wear – extending the seal’s lifespan.
- Application:
They are widely used in dynamic applications like reciprocating rods and plungers and rotating or reciprocating shafts, where resistance to friction and wear are critical.
O Rings:
These seals have the prefix ‘O’ because of their circular or torus cross-section. They are typically made from elastomers but can also be made using specialized compounds for specific applications.
- Reduced Sealing Performance:
An O ring can be used in static applications or low speed pivoting movements, because its surface creates spiraling or twisting movements, resulting in reduced sealing performance.
- Ease in Installation
O rings are easier to install and their simple design makes them preferable for smaller spaces. They are also much easier to manufacture.
- Compression Set:
O rings are more prone to compression set or permanent deformation over time.
- Application:
They are widely used in static or dynamic applications with reduced relative movement, such as rotating pump shafts and hydraulic cylinder pistons.
