Groove dimension for Internal and External pressure (Vaccum)

[Jezovuk]

Hello!
I'm constructing a pressure vessel which is intended to work with both- internal pressure (4 bara) and vacuum (~0,2 bara)- (not simultaneously of course).
The vessel have normal flange and cover (static- axial sealing).
When i look at the catalogs, manufacturers always separate internal and external pressure applications so i can not find any recommendations for groove dimension in this case.

I would appreciate the answer. Thanks in advance.

 

[Tmoose]

" groove dimension "

Are you using o-rings?

 

[Jezovuk]

Yes, i use O-rings.

 

[Jezovuk]

Maybe O-ring is not the best solution when dealing with both vacuum and internal pressure?
Did anyone had a similar problem?

 

[Compositepro]

O-rings can handle pressure in either direction and with the direction changing. With changing directions, it is more important to design the groove to tight tolerances to minimize the o-ring movement that will occur. The movement will cause more wear on the ring.

 

[Jezovuk]

Compositepro, thank You for your answer!
That means that for example for O-ring ø188x4 (188- internal diameter) i need a groove ø196/ ø188? (with standard depth)
I am asking that because every O-ring manufacturer recommended that a groove should not be filled more than 85% or significant damage on O ring can occur.

 

[Chpal1984]

The actual diameters of your groove will depend on your cross sectional width of your o-ring. Also is this a face o-ring or on a shaft/hole?
If you have a copy of BS1806: 1962 this will give you the dimensions you need, alternatively I just found this online www.applerubber.com/src/pdf/seal-design-guide.pdf

If it was me I find 3.53 mm o-rings work well around the pressure you are talking about.

Also I generally have the ID machined slightly bigger than the ID of the O-ring, this stretches the oring a bit and just helps hold everything in place during assembly

 

[Compositepro]

The bible is the Parker O-ring Handbook.

https://www.parker.com/literature/ORD 5700 Parker_O-Ring_Handbook.pdf