Explosive Decompression concerns with Flexible Graphite
Explosive Decompression concerns with Flexible Graphite
(OP)
Can anyone advise on the susceptibility of flexible graphite (trade names "Grafoil", "Papyex" etc.) to explosive decompression (ED) or rapid gas decompression (RGD) in a multi-phase hydrocarbon production environment?
The application I am considering does not involve sealing with flexible graphite, rather, the flexible graphite is only being used as a compliant spacer between 2 parts. Thank you in advance.





RE: Explosive Decompression concerns with Flexible Graphite
RE: Explosive Decompression concerns with Flexible Graphite
Can flexible graphite "collapse" from hydrostatic pressure? In other words, is there a possibility that flexible graphite exhibits a "shrinkage" in volume when exposed to high ambient pressure (from, say 15 to 30 ksi)?
This does happen in case of "closed cell" materials like Styrofoam. Technicians in my company often throw some Styrofoam cups in equipment being hydrotested to "shrink" them.
"The engineer's first problem in any design situation is to discover what the problem really is."
"A good scientist is a person with original ideas. A good engineer is a person who makes a design that works with as few original ideas as possible."
RE: Explosive Decompression concerns with Flexible Graphite
Please give me a shed of light. What is the Explosive Decompression ?
Regards,
RK
RE: Explosive Decompression concerns with Flexible Graphite
RE: Explosive Decompression concerns with Flexible Graphite
Graphite seals are not susceptible to ED because the diffusion rate of the gas into, and back out of the graphite is fast enough that upon rapid pressure drop, the gas exits the graphite before it has time to expand.
Thermoplastics (such as PTFE, RPTFE, Nylon and PEEK) are not susceptible to ED because the gas doesn't permeate into the material.
RE: Explosive Decompression concerns with Flexible Graphite
one addition however - I've used many thermoplastics & elastomers in hydrogen gas sealing applications, and even the thermoplasic/elastomeric seals become succeptible to explosive decompression due to the nature of the tiny molecules (or the ioinc constituents especailly) to ingress the seal. As with most things, it comes down to application (media/pressure/tempeature/decomp. rate vs diff. rate)
So, 450°F, max 30ksig, what media?