Low friction oring

[Antrozous]

Hi all,

I have an application that has to seal a rod (just under 0.625", this part diameter is negotiable) against a tube with an inside diameter of .625". The rod protrudes through the tube and must be able to move fore and aft freely.

The rod is machined from delrin, and the tube is machined from a high strength alloy aluminum.

If you're wondering, yes, it's a valve. The idea is to maintain a seal in the closed position at ~500psi, yet it needs to open and close with minimal fore/aft force.

I'm using a series of orings to control open/closed positions, seated in the inside diameter of the tube. This is so the orings can bear against the lower friction delrin instead of aluminum.

In prototyping, the parts worked fine together...then I added the orings. I'm currently using 1/16" "Quattro" 'x' style orings with a Dow 33 grease type lubricant. Friction is still unacceptably high.

So now I'm back to the drawing board on what oring to use. Any suggestions?

 

[MikeHalloran]

I'm wondering how your description translates into any kind of valve that I've ever seen. A sketch might help.

In the meantime, if you want to seal a plunger with low friction, consider BalSeals. They don't rely on grease for low friction.





Mike Halloran
Pembroke Pines, FL, USA

 

[Eltron]

Like Mike said, BalSeals is a good place to start. Also, check Minnesota Rubber's catalog.

Dan

http://www.eltronresearch.com

Dan's Blog

 

[hydtools]

Reduce the radial squeeze. Increase the durometer for less squeeze under pressure.

Ted