Conical Section to Reverse Flange Joint Design 1

[pperlich]

I'm going to discuss this with my AI, but wanted some other input before I do.

Section VIII-1 (2019)
Conical shell section with small end welded directly to reverse type flange:

1. Weld Joint Category C?​

2. Weld type 7? Does the half-apex angle matter? (I don't think it does, if this is a Cat. C joint.)​

3. Assuming the flange is designed per App. 2-13(b) and the attachment is per Fig. UW-13.2(a), if the half-apex angle is >30° is a transition knuckle required or do the requirements of 1-5(e) apply?​

Note that the large end attaches to a cylindrical shell section and has a knuckle.

 

[SnTMan]

pperlich, couple of things first: I infer external pressure does not apply and my remarks are based on 2017 Ed.

1) Yes, Cat C, UW-3(c).
2) I'd say, yes Type 7, I don't think the half apex angle is important for assigning the type of this joint.
3) If the half-apex angle exceeds 30 deg 1-5(e) would not apply. See 1-5(a). See also UG-36(e)(5)(b). Special analysis per 1-5(g) would apply. I don't know if an industry standard analysis exists. I'd avoid it if possible.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Some Curious Guy]

The post is satisfactorily answered by @SntMan.
I am just wondering that a cone behaves like an axial spring. More the apex angle more the flexibility of the cone. A flange attached to cone would face more rotation as compared to flange attach to the shell and maybe the potential for leakage is more. Isn't it recommended to attach a small shell hub to the cone to add more rotational stiffness to flange joint junction ??. Just an opinion though.

 

[r6155]

@ pperlich
Can you send us a sketch and more information?

Regards

 

[SnTMan]

Some Curious Guy, in my experience a cylindrical section on each end is the preferred design, and the Code assumed this to be the case. The alternate reinforcement calculations for cylinder(s) not present were added fairly recently (in old guy terms).

The problem with sloppy work is that the supply FAR EXCEEDS the demand