Maximum groove dimensions
Maximum groove dimensions
(OP)
Hi everybody,
The gland fill factor for O’ring seals is normally recommended from 60 to 85%.
Elastomer thermal expansion and swell are known reasons for restrictions of maximum fill. In other words, these issues impose minimum groove dimensions for a given O’ring section.
But, what about the minimum fill? Which are the governors for the maximum groove dimensions?
I would like to know what should be take in account to evaluate a groove improperly made bigger than specified.
I would appreciate any help.
The gland fill factor for O’ring seals is normally recommended from 60 to 85%.
Elastomer thermal expansion and swell are known reasons for restrictions of maximum fill. In other words, these issues impose minimum groove dimensions for a given O’ring section.
But, what about the minimum fill? Which are the governors for the maximum groove dimensions?
I would like to know what should be take in account to evaluate a groove improperly made bigger than specified.
I would appreciate any help.





RE: Maximum groove dimensions
RE: Maximum groove dimensions
Easy. It's scrap.
Mike Halloran
Pembroke Pines, FL, USA
RE: Maximum groove dimensions
Regarding movement, it is a static application, but the seal will be submitted to pressure transients.
Operational pressure shall be around 3000 psi oil and gas. Temperature may be from 0oC to 82oC. Seal is fluorocarbon rubber 90 shore A.
Mike,
The groove has an improper width only. There is no compromise in its depth or in diametric clearance. Surface finish of all groove surfaces is according to specified.
Could you, please, explain your proposal of scrap damage?
Thank you both.
RE: Maximum groove dimensions
trust this helps
RE: Maximum groove dimensions
How much error do you have and what is the application, perhaps best you explain this too unless you have an answer now.
good luck
RE: Maximum groove dimensions
At that pressure, everything has to be perfect, and you should be using anti-extrusion rings anyway, so maybe you need a little more width to fit them.
Use two rings, so there's no chance of confusion about which side the ring should be on.
Mike Halloran
Pembroke Pines, FL, USA
RE: Maximum groove dimensions
This O'ring is piston type assembled. It is used in a sealing sleeve between two parts of a subsea oil and gas production tool.
Despite the high pressure, according to our experience, we does not use back-up rings in this kind of application. If I prescribe a back-up ring to reduce width of one groove in one piece it may represent problems when that specific equipment will be submitted to disassembling for maintenance. Otherwise, to scrap the piece seems too much to me.
It’s not the first time I face this mismanufacturing problem, but I couldn’t figure out a failure mode that could be associate to a wider groove.
I agree that spiral failure may be a concern if O'ring is free to roll. But, the groove will be wider no more than 0.060" (in the specific case it will be only 0.030" wider) and it seems no serious threat.
RE: Maximum groove dimensions
Downhole? Undersea?
What does it cost to replace a blown o-ring there?
Mike Halloran
Pembroke Pines, FL, USA
RE: Maximum groove dimensions
Ed Danzer
www.danzcoinc.com
www.dehyds.com
RE: Maximum groove dimensions
It's not downhole. And it's not resident equipment that would have long-term operational periods. It's a tool that is submitted to maintenance before each use.
I don't think that spiral failure should be a concern just because of a 0.060" wider groove for a static application. This is that I meant.