Using Toroidal Ring to prevent static ignition of hydrogen 1

[gene2007]

I have been told that toroidal rings are installed at the atmospheric discharge point on hydrogen relief lines to prevent static ignition. I have had no success searching the web for information on these devices or finding companies that sell these devices. Would someone please enlighten me?

 

[unclesyd]

NASA usually electrically isolates the top section of their H₂ vent stacks. This enables them to have a spark gap outside the H₂ stream.

Here is where they mention the torodial ring and its pupose.
I would imagine thatthere is a lot more information if you look around NASA.

http://www.nasa.gov/offices/oce/llis/0242.html