Eccentri shell with Cone

[K.P.M.]

Hello Everyone,
Happy new year…

I come across some queries regarding Eccentric Shell Design by use of Cone.
I attached here our client requirements detail view of their product.
As we discuss with our AI, He tells us to change the design & also says that need to
Proof test of that cone with both side shell .
Please suggest me to solve this issue. We need 70mm eccentric shell . For such cone
Which part of code ( ASME SECTION 8, DIV 1) is apply.? & also suggest weld geometry .

ASME CODE: Section 8, Division 1
Design Pressure: 60 psi
Refer attachment.

Kejul Mistry

 

[K.P.M.]

Refer attachment here

 

[SnTMan]

KEJUL, the rules of UG-36(g) could apparently be applied to this construction, as it places no restrictions on the relative position of the two cylindrical axes.

Your AI, I'm sure, is aware of these rules and is not convinced they can be applied. Whatever you do, the AI will have to be satisfied.

As to weld geometry, I'd go with full penetration butt welds.

Regards,

Mike



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

 

[K.P.M.]

Mike Thank you,

Here AI says that as per fig ug-36 (e) angle Alpha 2 should not outside shell.
In our case , that angle is outside. So can any one suggest how to convince AI. Ot
Other option.


Kejul

 

[SnTMan]

KEJUL, I really think you have U-2(g) design there. You are going to have to come up with an analysis that suits your AI, or change your design.

Regards,

Mike

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

 

[K.P.M.]

Hello,

By continuing this topic,

In our case , there is jacket on only top shell which have
500 shell length. Now to find external pressure limit
We take L= 750 mm (500+150+100) as per fig. UG-28.1 (a-2).
Should we take L=750mm for both top (500 mm) & bottom shell (100 mm)
for individual calculation of shell.?

Is it right or wrong?

Or suggest.


Kejul Mistry

 

[SnTMan]

KEJUL, so top shell (8 NPS) only is subject to external pressure due to jacket correct?

If so, you might take the jacket closeout as a line of support, giving L approximately equal to 500.

You would normally take the cone-cylinder junction as a line of support, however with your design, I don't think this is feasible.

If the entire vessel is subject to external pressure, then I suppose you could calculate each cylinder and the cone separately taking L as 750 for each. This would yield a greater required thickness for each section.

Given the proposed design, you might take it up with your AI.

Regards,

Mike



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

 

[K.P.M.]

Thanks Mike,

Yes, only 8 NPS pipe is covered with jacket. So should i take L= 750 or 500 for top shell?

& our design pressure is Full vacuum to 0.4 MPa.


Kejul Mistry

 

[SnTMan]

KEJUL, if you would review the definition of L in UG-28, you would see that a jacket closeout that meets requirements of Appendix 9, 9-5, can be considered a line of support, allowing you to use L of approximately 500.

I say approximate because location of the closeout is unknown and what serves as a line of support on the opposite end, away from the cone, is also unknown. As is most everything else in this design.

Regards,

Mike

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