Any drawback to a very smooth O-ring gland for static gaseous system? 4

[PULAOKHAO]

AS-5857A "GLAND DESIGN, O-RING AND OTHER ELASTOMERIC SEALS, STATIC APPLICATIONS", Table-6, page-37, lists 32 micro-inch max for O-ring groove dia & 63 micro-inch max for groove sides. It does not lists any restrictions on the min side.

Is anyone aware of any drawbacks for a radial, static O-ring seal in a gaseous system where the pressure difference across the seal does not exceed 1 atmosphere if the groove surface is very smooth [less than 1 micro-inch Ra]?

The squeeze is 27%; O-ring elastomer is butyl; 3.5 inch dia and 0.070 inch cross section

 

[monkeydog]

None I am aware of, it's the larger surface finish that is normally the problem with leakage.

 

[PULAOKHAO]

"monkeydog", thanks for prompt response. If anyone else is aware of any issue, please post. Thanks

 

[hydtools]

Not aware of static gland issues.
Dynamic glands generally should have some minimum for the dynamic surface to retain lubrication so as not to burn the seal.

Ted

 

[PULAOKHAO]

"hydtools", yes, I am aware that dynamic seals should have surface roughness no smoother than 5 Ra but this is static

 

[MikeHalloran]

The less than 1 atmosphere differential can be a problem if assembly technique distorts or twists the seal and lubrication is inadequate or absent.

Super smooth finish shouldn't hurt, but I've never worked with a gland _that_ smooth.







Mike Halloran
Pembroke Pines, FL, USA

 

[ornerynorsk]

Dissassembly, when it becomes necessary, might be interesting. The seal will likely bond very well to the smooth surfaces, depending on the material.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[HDS]

Cost of making the groove smooth.