Description
O-Rings are installed as a flexible barrier to prevent leakage but are vulnerable to being pinched or torn. Back-Up Rings help mitigate these issues by reinforcing the O-Rings with a stiffer material. There are three main types of Back-Up Rings: Spiral, Split, and Solid. These are typically made from either PTFE or Nitrile 90 shore materials, each offering unique benefits for protecting the O-Rings.
Types and Materials of Back-Up Rings
- Solid Split (PTFE):
- Used to prevent extrusion of the O-Ring at pressures above 100 bar.
- Provides a stable and robust support structure.
- Spiral (PTFE):
- Ideal for applications with temperature fluctuations.
- Even if the Back-Up Ring experiences post-shrinkage, at least one turn of the spiral remains in contact with the O-Ring, preventing extrusion.
- Can be adjusted for non-standard diameters by shortening the ring.
- Parbak (NBR):
- Features a one-piece contoured design that enhances the performance of the O-Ring under high pressure.
- Easily stretchable into place.
- Reduces localised wear on O-Rings, unlike other types of Back-Up Rings.
By using these Back-Up Rings, the overall integrity and longevity of the O-Rings are significantly improved, ensuring reliable performance in high-pressure and high-temperature environments.
