Eccentric reducer on pressure vessel

[vessexst]

Hi all,

I am designing a vertical vessel.

Design P = 150 Psig
Design temp = 150 Deg C
MOC = SA 516 70N

There are two shells of ID 36" and 30". These two are connected via an eccentric reducer. I need to put two stiffener rings at both the large and small ends in order to satisfy reinforcement requirements as per App. 1-5 and UG 36.

However, the maximum that I can locate both these rings is 13 mm (each for ring of small end and large end for respective shell CS seams)

Since this is very near to shell seams, I think of doing a full RT of these welds. But, then again, the welds are not overlapping but just close to one another. Is it possible to conduct full RT in this case?

 

[SnTMan]

However, the maximum that I can locate both these rings is 13 mm...

Don't know how to interpret this statement.

Is it possible to conduct full RT in this case?

After the rings are attached it might be difficult, but before, easy.

Regards,

Mike



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

 

[r6155]

Why not a reducer as per ASME B16.9?

Regards

 

[SnTMan]

Yeah, if you could find one...

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

 

[vessexst]

It is just that weld seam to seam distance is vsry less

However, this is the max distance permitted by ASME. If anyone has a similar experience, kindly tell.

@r6155: Actually, I am doing it on PV ELITE. It takes UG 36 and App 1-5 as its basis. But, is there anything ASME specifies in case of close distance welding?

 

[r6155]

Use hand calculations.
Which is the angle of reducer?, and the thickness?

Regards

 

[SnTMan]

vessexst, Code does not address this to my knowledge, so:

1) make your circ seams, inspect as desired. RT, etc.

2) Attach stiffening rings. Inspect as desired. Visual, MT, etc.

3) Get on with life

Not an ideal situation, but not uncommon either.

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

 

[vessexst]

@r6155: Apex angle is 7 Degrees

Thickness = 6 mm

 

[r6155]

@ vessexst
Reinforcing rings are not required. Shell 30" and 36" also 6mm thickness.

Regards

 

[SnTMan]

vessexst, you might want to confirm the PVE calc. I seem to remember Codecalc was troublesome for eccentric reducers...

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

 

[vessexst]

@r6155: The reinforcement is required under external pressure in order to satisfy the required moment of inertia requirements. The available moment of inertia without stiffeners is less.

@snTman: I have actually also done manual calcuations. I did not see any discrepancy between PV Elite and ASME

 

[r6155]

@ vessexst
Your post is for PD= 150 psi, not external pressure.

Regards

 

[SnTMan]

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