FLUID MEDIA AND PTFE SEALS:
You may not be aware of the fact that the fluid media has a significant effect on seal wear. In this article, we are going to explore exactly how fluid media can affect the performance of your PTFE spring-energized seal.
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Wear and Lubrication
Fluid media can mean anything from liquid helium to fuel, alcohols, polymers, paint, hydraulic fluids, solvents, or simply air. The type of fluid can impact seal wear. For example, given the same seal PV values, gases will result in the greatest wear, followed by water and then oil. Some liquids can also provide a degree of lubrication, which is likely why in our example oil results in the least amount of comparative wear.
Media present around the seal lip serves to dissipate heat that is generated at the seal interface, as well as reduce temperatures. Heat contributes to adhesive wear, the main mechanism of wear for thermoplastic seals such as PTFE. Excessive temperature can severely compromise the performance of a seal.
Required Surface Finish
The type of fluid also determines the surface finish of the hardware. The table below shows the recommended surface finish based on the type of media, and whether or not it will be at cryogenic temperatures.
Consider the type of media
When developing the specifications for your next spring-energized PTFE seal, dont forget to take into account the type of media that will be involved.
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