Effective gasket area
Effective gasket area
(OP)
Hi Guys, I am currently trying to calculate Wm1 using the effective gasket area on a Slip-on flange raised face. According to AS1210, Wm1= H + Hp with Hp= 2*b*(pi)*G*m*P.
I got different answer Hp= b*(pi)*G*m*P and dunno why here's what I have done:
Hp= P*m*A where A is the total area of gasket based on effective gasket width b hence, the overall effective width of the gasket is 2b. therefore A= (pi/4) * ((G+b)^2-(G-b)^2)
and that will give A=G*b*(pi) and Hp=b*(pi)*G*m*P.
could anyone clarify this please ?
I got different answer Hp= b*(pi)*G*m*P and dunno why here's what I have done:
Hp= P*m*A where A is the total area of gasket based on effective gasket width b hence, the overall effective width of the gasket is 2b. therefore A= (pi/4) * ((G+b)^2-(G-b)^2)
and that will give A=G*b*(pi) and Hp=b*(pi)*G*m*P.
could anyone clarify this please ?





RE: Effective gasket area
Where did your 2b go?
Regards,
Mike
RE: Effective gasket area
RE: Effective gasket area
As far as I undertand you have confused with the definitions. I have attached a pdf file you may see the definitions and the formula all together.
In the file Pt = P + Pe
where
P = design pressure
Pe = 4 Fe / ( pi G^2 ) + 16 Me / ( pi G^3 ) , the equivalent pressure for external forces.
Hope it helps,
Ibrahim Demir
RE: Effective gasket area
Thanks,
Marc
RE: Effective gasket area
The seating width in the equation Wm2= b*(pi)*G*y was probably reduced (from 2b to b) to account for flange rotation.
Read the article about flange rotation on the links below...
h
http
RE: Effective gasket area
In the older days, the standards used to include the source of information as the reference. Nowadays, there is no such a thing. We always try to educate the engineers and ask them not to use the formula blindly. However, we do not give them the background at all.
I wish there are others can join me to convince the standard committees to include the references.
I know that AS1210 is the mixture of British and ASME codes and Australian Standards are not backed up by any test on the pressure equipment at all. When you ask the committee members they always say they do not have the resource even to write or collect information, and ask for your involvement.
The ASME codes are the same for the reference issue.
I recently have tried to find the background of the flange calculation in accordance with ASME code especially I concentrated on the gaskets. There was nothing available and the responds were not encouraging. I found a link of the background of EN 13445 which includes the flange calculation. It may be useful for you but it is written differently, understanding might be a bit difficult without having EN 1591 or/and EN13445.
http://www
Hope it helps
Ibrahim Demir
RE: Effective gasket area