Low pressure sealing

[Parsnip]

Hi,
I hope someone can help.
I am looking to design an 'o' ring sealing system for a low pressure application (<200psi). I have been given some formula from an article written by Seals Eastern Inc that calculates the compression force, contact area and peak contact stress. Where as the formulas for the compression force and conatct stress seem logical, that for the contact area seems wrong.
The equation I have been given the conatct area is:
b = 2.4x where x is the seal deflection and b the conatct area (in^2).
My questions are :
If the o-ring is squashed should the contact area not be the area of the plane shape formed between the two surfaces?
Should the contact area actually be twice this plane area as the o-ring is squashed both in the groove and by the housing?
I hope this makes sense and someone can help otherwise I risk having a very leaky system!!
Cheers
Caroline
I

 

[RNDguy]

Caroline,
I do not have this article, but sounds like you are only designing a static seal. Or is there a rotating shaft involved? What rpm? What dia? I suggest looking into the Parker Seal catalog. Also, O-rings are not the best seal under dynamic conditions, I would suggest in that case to look into loaded lip seals, mechanical seals etc. Hope this helps.

 

[RNDguy]

I found Parker catalog online:

http://www.parker.com/o-ring/Literature/02-5700.pdf

Good luck.