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Flange design gasket oustide studbolts

Flange design gasket oustide studbolts

Flange design gasket oustide studbolts

(OP)
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?

RE: Flange design gasket oustide studbolts

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
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

RE: Flange design gasket oustide studbolts

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

Indeed an unusual setup.

RE: Flange design gasket oustide studbolts

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

RE: Flange design gasket oustide studbolts

(OP)
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".

RE: Flange design gasket oustide studbolts

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

RE: Flange design gasket oustide studbolts

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

RE: Flange design gasket oustide studbolts

(OP)
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.

RE: Flange design gasket oustide studbolts

flaka, can you post a figure of your flange? (see FAQ559-1177: How Do I Make Files Available For Download? ... No Emails Required). 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 HD,HG,HT 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 hG=(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

RE: Flange design gasket oustide studbolts

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?

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