Level Spud Reinforcement Calcs
Level Spud Reinforcement Calcs
(OP)
When a level transmitter spud (its thickness greater than the head or shell into which it is welded) is welded into an ASME pressure vessel, would this spud need reinforcement calculations per UG-36(c)? I question this because the spud will always be plugged or have transmitter installed, thereby becoming one unit.





RE: Level Spud Reinforcement Calcs
Probably not. As long as the cutout in the head or shell is less than 2 3/8" you'll be exempt from reinforcement calc's per UG-36(c)(3)(a), and it would be an unusual level transmitter which would require a larger connection. The thickness of the attached nozzle doesn't enter into the reinforcement reuqirement exemption.
My definition of a spud (see, for example http://www.wfi-intl.com/ and go to "products" and look at "flanged pipet")may vary from yours; we only use them on piping. I'd use a long weld neck nozzle for level instrument connections in vessels.
jt
RE: Level Spud Reinforcement Calcs
RE: Level Spud Reinforcement Calcs
The fact that the hole is always filled is immaterial; the stress is not carried by the plug part but by the outer frame. The thickness of the item wouldn't exempt it from reinforcement calculations, but may make the fitting self-reinforcing, where no additional reinforcing plate is required.
You may need to radiograph, hydrotest, etc., after welding it in, as well.