PEEK Back Up Ring Oil & Gas:
One of the popular choices for seals for the intense, high pressure, corrosive, high temperature environments found in the oil and gas industry is a combination of a PTFE spring-energized seal with a PEEK back-up ring (BUR) installed on the downstream side of the seal gland. Why?
Need more information? Check out these PEEK resources and articles rom the Advanced EMC Technologies:
- PEEK in Oil & Gas Industry Guide (Detailed Download)
- Take a PEEK: Oil and Gas Industry New Sources
- Take a Peek: Environmental Impact of PEEK in Oil & Gas
Reliability under High Pressures
Spring-energized seals don’t just perform well, they perform their best when the pressure increases. These seals were made for high pressure, high speed applications that need reliable, long-lasting seals. PTFE is an excellent material for high pressure spring-energized seals for several reasons, including its almost universal chemical resistivity, its range of operating temperatures, its low friction, its dry running capabilities, and its strength.
Performance at High Temperatures
What happens to materials exposed to extreme environments? They experience deformation, extrusion, and can begin to degrade rapidly. And as temperatures rise, so does a polymers resistance to extrusion and deformation. The first hurdle to overcome in developing a seal for extreme oil and gas applications is to choose a material with a high enough maximum continuous operating temperature. As you can see in the chart below, polymers like PTFE, PEEK, and Torlon quickly rise to the top.
Prevention of Seal Damage
Back-up rings aid in preventing damage to critical seals that are continuously exposed to high temperatures, high pressures, and large extrusion gaps. They do this by helping to combat extrusion and deformation, which if allowed to occur unchecked can result in a catastrophic failure.
Back-up rings are typically made of a hard material that is extrusion resistant, including polymers such as PTFE and PEEK. Both PTFE and PEEK possess incredible chemical resistivity, low friction, similar temperature ranges, and low wear rates. One of the major areas of difference is their hardness: PTFE has a Shore hardness of D50, while PEEK has a Shore hardness of D85. PEEK has been found to be an excellent companion to a PTFE spring-energized seal.
Conclusion – Oil & Gas Industry Requirements
The design requirements faced by engineers in the oil and gas industry aren’t going to get any easier; if anything, the continued search for oil in new places will likely on increase factors like pressure and temperature requirements. One dependable solution for high pressure, high temperature sealing requirements in the oil and gas industry is to use a PTFE spring-energized seal with a PEEK backup ring. Both materials are strong, low friction, and well adapted to extreme temperatures. Combining them in this fashion puts their best properties to optimal use, resulting in a strong, stable, reliable seal.
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