Tangential nozzle 2

[PMCap]

Can anyone provide me at sketch/detail for welding a 3" x 0.438 wall tangential nozzle into a 132" OD x 0.375" wall shell and haveing a 0.25" all arond inside diameter wear plate. Code is ASME Section VIII, Div. 1.

Thank you in advance

 

[jt1234]

We have this several times, nothing special, just weld all together.

 

[Christine74]

If possible it's probably best to use a thicker nozzle in order to avoid having to install a reinforcing pad due to its irregular shape, and you will need to run reinforcement calculations in both the radial and axial directions due to the large radial cutout opening.

(Photo taken from

http://www.mntfab.com/joomla/index.php/component/content/category/9-uncategorised.html)

-Christine

 

[r6155]

PMCap
"0.25" wear plate around the inside diameter".
Did you say around the nozzle or around the shell diameter?

Regards

 

[PMCap]

The 1/4" wear plate is welded around the inside of the vessel 360 degrees and all around the nozzle

 

[r6155]

PMCap
This design is not allowed in ASME. Increase the shell thickness.

Regards

 

[PMCap]

r6155 - I'm a bit confused as to why you say that the design is not allowed by ASME. Perhaps you could provide some clarification as I have seen numerous ASME Code compliant configurations for attachment of a tangential nozzle.

tangential nozzle is welded to shell per UW-16 (d)
wear plate inside is full penetration to nozzle and fillet welded to shell
there is a nozzle reinforcement pad on the outside that is full penetration welded to the nozzle and fillet welded to the shell


Design Pressure is 20 psig @ 600 F
service is steam blowdown tank - non lethal service
shell is 132" OD x 3/8" thk
nozzle is 3" sch 160
reinforcement pad is obround shape with a minimum dimension of 2.875" all around tthe nozzle x 3/8" thk.

Regards

 

[jt1234]

The design is allowed by Code. No restriction of tangential nozzle as long as it is well reinforced the opening per code. The wear plate is just an non-pressure part all around the vessel, welded to both vessel and nozzle for tangential flow which may contain particles. Lots of applications in the industry, not a big deal.
Using integrally reinforced nozzle may be ok, however, you will face a challenge in fabrication to contour the thick nozzle and how to design welds to satisfy code reinforcement requirement for the weld.
Fortunately your nozzle is only 3" you many not even need extra reinforcement.
For special service that re-pad is not allowed and with large nozzle that required extra reinforcement, in addition to thicker nozzle, a thick local insert plate is an option.

 

[r6155]

The shell must be a SOLID PLATE.

Regards

 

[PMCap]

r6155 - The shell is a solid plate. What else could it be?

Regards

 

[r6155]

A cylindrical wear plate 0,25", as you mentioned, over a shell plate 0,375” is not a solid plate. Please see ASME VIII-1
Use a solid plate 0,625”

Regards

 

[Geoff13]

Since your opening will be an ellipse with greater than 2:1 ratio, you must account for the additional reinforcement required by UG-36(a)(1). The Code doesn't specify how to do this so presumably you'll have to use U-2(g).

 

[Geoff13]

Always looking to learn something new about the Code.

A cylindrical wear plate 0,25", as you mentioned, over a shell plate 0,375” is not a solid plate. Please see ASME VIII-1

Figure UG-40(c) shows an internal reinforcing plate, so an internal wear plate would seem to be even more acceptable. A wear plate is just corrosion allowance so I wouldn't think the Code would care too much about it. This wear plate seems similar to partial strip lining under UCL.

Could you provide a Code paragraph reference that says an internal wear plate is not permitted?

 

[PMCap]

Thanks to all for the responses.

 

[r6155]

Geoff13
let's assume a clad plate 10mm CS with 4mm SS, total 14mm (solid plate) Do you understand that you can replace this clad plate with a 10mm CS plate plus a 4mm SS plate?.

Regards

 

[david339933]

This is required for blowdown tanks in Canada.