In demanding industries like oil and gas, downhole applications, and high-pressure hydraulic systems, sealing solutions must withstand extreme conditions. One critical component that enhances seal performance is the backup ring. Made from durable materials like PTFE (Teflon) and PEEK, backup rings prevent extrusion, improve longevity, and ensure reliable operation in piston and rod applications.

What Are Backup Rings?

Backup rings are non-metallic support rings installed next to primary seals (such as O-rings) to prevent extrusion under high pressure. They act as a barrier, distributing stress and reducing seal deformation—especially in dynamic applications involving pistons and rods.

Key Functions of Backup Rings

Prevent Extrusion: High-pressure conditions can force elastomeric seals into gaps, leading to failure. Backup rings reinforce the seal, blocking extrusion.

Enhance Seal Life: By reducing stress on the primary seal, backup rings extend operational lifespan.

Improve Performance: They maintain seal integrity in extreme temperatures and aggressive media (e.g., hydrocarbons, drilling fluids).

Common Materials for Backup Rings

1. PTFE (Polytetrafluoroethylene)

Advantages:

• Excellent chemical resistance (ideal for oil and gas applications).
• Low friction, reducing wear on piston rods.
• Performs well in high-pressure and high-temperature (downhole) environments.

Limitations: Less rigid than PEEK, making it better for moderate pressures.

2. PEEK (Polyether Ether Ketone)

Advantages:

• Superior mechanical strength and rigidity, resisting extrusion in ultra-high-pressure systems.
• Outstanding thermal stability (up to 250°C/480°F).
• Resistant to harsh chemicals, making it ideal for downhole drilling and hydraulic systems.

Limitations: More expensive than PTFE but justified for extreme conditions.

Applications in Oil & Gas and Downhole Environments

Backup rings are crucial in:

Hydraulic cylinders (supporting rod and piston seals).

Drilling equipment (preventing seal failure in high-pressure downhole tools).

Subsea systems (resisting seawater and hydrocarbon exposure).

Valves and pumps (ensuring leak-free operation under cyclic pressures).

Choosing the Right Backup Ring

Consider:

• Pressure & Temperature: PEEK for extreme conditions, PTFE for moderate pressures.
• Media Compatibility: PTFE for chemical resistance, PEEK for aggressive hydrocarbons.
• Dynamic vs. Static Use: PTFE for low-friction movement, PEEK for rigid support.

Backup rings are unsung heroes in sealing technology, especially in oil and gas, downhole, and high-pressure hydraulic systems. Whether made from PTFE for flexibility or PEEK for extreme durability, they play a vital role in preventing extrusion and enhancing seal performance in piston and rod applications.

Investing in the right backup ring material can mean the difference between frequent maintenance and long-term reliability.