Welding of bellmouth inside tank

[MattNCSU03]

As a followup to [thread292-471719], we have existing a settling tank fabricated from pipe to B31.1 with an 18" flanged end. As discussed in the old thread, I'm designing a new exit for the settling tank and arrived at 18x6 reducing weld neck flange welded to 6" stub end to connect to the new loop piping. The scientists sponsoring the test want a bellmouth exit for the tank so I've found one that could be used. It would be welded to the flat side of the weld neck flange (thus inside the settling tank). I've attached a rudimentary sketch. We consider it to be inside the pressure boundary (not part of it). See attached sketch. Is such an arrangement allowable under B31.1? If so how should be it be treated under the code? As a side-note we use B31.1 out of an abundance of conservatism. The test loop this is going in to is unheated (actually chilled to keep temperature at ambient) and operating under 250 psi.

Thanks,
Matt

 

[LittleInch]

It's a little odd but as it's not a pressure boundary you can do what you want so long as it doesn't impact the flange loading.

It's not easy to get a good fillet weld at that location.

It doesn't fall under 31.1 in my opinion.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MattNCSU03]

@LittleInch Thanks!

 

[marty007]

Just be careful that all welding is done to ASME IX.