ORING PTFE WHITE

PTFE offers many distinct advantages over elastomers. These advantages include corrosion resistance, massive temperature range capabilities, excellent electrical properties and an almost unlimited shelf life, to name a few.

But some considerations should be taken into account before making the switch to a PTFE O-Ring.

While PTFE offers some distinct advantages over elastomers, it also has some draw-backs that can negatively affect seal performance.

Eclipse offers fully customized PTFE O-Ring sizes out of our full range of PTFE blends that can help boost performance and longevity for your seals. But in some cases, an Eclipse Spring Energized seal might be the best choice for optimal sealing performance.

Here’s how to determine whether a PTFE O-Ring or Spring Energized seal is the best for your application.

Higher hardness

Virgin PTFE’s hardness is 55 Shore D, which is much harder than a typical Nitrile O-Ring at 70 Shore A, which is a softer scale.

The higher hardness negatively affects sealability, as the material doesn’t conform the mating hardware surfaces as easily.

Leakage rate

While rubber O-Rings might conform to “as machined” surfaces, PTFE may require post-process surface finish improvements to control leakage to acceptable levels.

In general, under normal conditions, the leakage rate for a PTFE O-Ring will be higher than any elastomeric compound.

The use of a PTFE O-Ring isn’t recommended for applications that don’t require extreme temperature or severe chemical conditions.

Inelasticity

PTFE’s nature as an inelastic material means that reuse or multiple installations of the same seal will not be possible.

Unlike rubber compounds, PTFE will not return to it’s original shape and cross-section once deformed during installation and use. That means PTFE O-Rings are typically only recommended for static face seal or flange type configurations that are not actively engaged and disengaged.

For example, a PTFE O-Ring would not be recommended for a chamber door seal that needs to be opened and closed frequently, as the O-Ring would likely have to be replaced after every use.

A reused PTFE O-Ring may look and perform similarly to a standard rubber O-Ring suffering from extreme compression set. But unlike rubber, this compression set occurs after only one use.

More often, PTFE O-Rings are found in flange gasket type applications where the seal will remain static and undisturbed until the next service interval.