Rules for sizing anti-siphon holes?

[JJJ2000]

Hello All,

I am trying to find some rational for sizing an anti-siphon hole on a dip tube into a vessel. The fluid is approximately 10,000 cP and flowing in an 8" pipe. I have read threads on here suggesting everything from 1/4" to 1/2" holes for this purpose. The vessel is a true ASME pressure vessel with 10 to 50 psig on it.

It seems the there are two concerns: plugging the hole with trash (or a thick glob of high-viscosity fluid) and providing a hole large enough to allow in sufficient air to break prime on the sucking piping (during reverse flow).

This material is transfered over with a gear pump, so I shouldn't have any large solids in the line, or my gear pump would destroyed itself.

I would expect even the smallest of holes would be sufficeint to break prime on the reverse flow line.

This leaves the glob of thick fluid to deal with.

Any thoughts?

Thanks,

JJJ

 

[Latexman]

Does this "stuff" have a natural tendency to approach a solid - polymerization, reaction, devolitilize, aging? Is there an identical or similar operation where you can ask about their experience? If not to all, I'd default to the company standard, ours is 3/8", until some experience is achieved.

Good luck,
Latexman