High temperature o-ring

[asimpson]

Here's a tall order.

I wish to seal over water pipe (o.d. 15mm) with a seal that allows easy withdrawal of pipe for maintanance. Something similar to an o-ring. Must be able to withstand temperatures up to 500C.

Cant think of an elastic materal that can withstand such temperatures. And I am aware water will not be liquid at such temperatures

Pressures shouldn't rise above 4 bar.

Thanks

 

[HDS]

500C is beyond even Kalrez (FFKM) or PTFE. Can you use a metal O-ring?

 

[moltenmetal]

asimpson: what you want does not exist. You need to reconsider your design, and properly qualify what you mean by "easy removal".

 

[dhengr]

Pipe unions, mean relatively easily removable.

 

[Compositepro]

Perhaps a packing gland or stuffing box?

 

[Eltron]

If you don't mind the ferrule then you should be able to find a simple compression fitting that would work. Take a look at Parker or Swagelok.

Dan

http://www.eltronresearch.com

Dan's Blog

 

[Cockroach]

Yeah, typical valve application, steam injection temperatures. No such material exists in commercial application, a few under the military specification.

I've used a leaded steel or bronze alloy effectively to get a seal in Ball Valve applications. Consider a soft metal, maybe a thermal plastic which is what is used in Check Valves.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[asimpson]

Thanks for replies. All very helpful.

I'll have to start thinking.

 

[unclesyd]

Take a look at these sample access systems from Metal
Samples, linked below. You could use a similar system to resolve your problem. There are many different systems available from other suppliers.

There are 2 primary ways to accomplish what you are trying to
do. One is to use a high temperature seal or move the primary
seal to a cooler area. I've used both methods to achieve both
dynamic and static seals on steam and polymer systems.

If you decide to use the packing gland at temperature approach as mentioned above their are still some packing available that work very well under your conditions. These packings incorporate mica, graphite, or asbestos. We use one that is an asbestos fiber with mica and a pinch of graphite.

If you decide to go the cool gland approach all you have to do is cool down to less than 300F.

http://www.alspi.com/access.htm