Flange design gasket oustide studbolts

[flaka]

Hi,
need to design a bolted flange with the gasket outside the boltcircle.
It can't be a full face gasket, it is a flat metal jacketed gasket.

Anyone?

 

[prex]

Quite an unusual setup, as you'll need a gasket under each nut.
Anyway I think that you should be able to use App.2 of Div.1 without changes, some lever arms will be negative and you should conserve the sign in the equations.

prex

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[flaka]

The outer gasket is on the fluid side, the bolts on the ambient side.

Indeed an unusual setup.

 

[Bobfromoh]

Difficult to visualize the flange geometry but what's going to stop the fluid from leaking through the bolt holes?

 

[flaka]

Medium is around the flange, and the flange has tapped bolt holes.
This is done for a "pull through floating head".
Like a tema head type: "t".

 

[jte]

If I understand the issue correctly, the proposed flange is similar to that shown in VIII-1 App 2 Fig 2-13 with the bolt hole and gasket surface reversed. I haven't pondered the implication much, but seems that the internal moment caused by the bolt-gasket couple is behaving the same way as it would for a normal flange. Thus, I'd start with a "normal" flange calc. The only thing substantially different is the flange is relatively smaller and, of course, needs to have internal access on both sides for bolt-up and will interfere with the fluid flow like an RO would.

jt

 

[Christine74]

What you're describing is called a "reverse flange." Guidelines for their design are covered in Appendix 2-13 of Section VIII-1.

These are used on floating head heat exchangers (TEMA "S" and "T") where the tube side has only one pass.

-Christine

 

[flaka]

Sorry for the unclearness...but it isn't a 2.13 type.

You could see it as a regular loose type flange (type 2.4) but with the gasket outside the bolts & the flange is positioned in the middle of a pipe.
The process fluid is around the flange and pipe.

 

[arto]

Take a look @ WRC #314 "Bolted Flanged Connections with Full Face Gaskets"

http://www.forengineers.org/cgi-bin/wrcbulletin/bulletin.pl?action=view;id=325

might be handy if you have to come up with your own eq's.

 

[prex]

flaka, can you post a figure of your flange? (see FAQ559-1177). I can't see how you can make the flange pair tight, as the bolt holes can be tapped on one flange, but cannot be on the mating one.
This flange pair could be considered to be subject to external pressure, and thus calculated per 2-11, but, as the gasket is outside the bolt circle, it behaves like a flange subject to internal pressure, with all three loads H_D,H_G,H_T acting in the same direction, thus adding up in the moment equation.
In my opinion, changing my position with respect to my previous post, you should calculate flange moments per 2-6 using h_G=(G-C)/2 and M₀=W(G-C)/2

prex

http://www.xcalcs.com

: Online tools for structural design

http://www.megamag.it

: Magnetic brakes for fun rides

http://www.levitans.com

: Air bearing pads

 

[unclesyd]

Are you talking about something similar to a head gasket where you have seal at each bolt hole?

Can you use a metal/metal contact for sealing?