Fill pipes and static electricity generation

[hollerg]

In thread 278-91957, one of the forum members mentioned using a fill pipe terminated against the side wall reduce fluid handling Static Electric Discharge Hazard. It is not clear to me that this is functionally equivalent to a dip pipe in reducing static generation from an air gap and splashing.

I would like to know how people terminated the fill pipe against a side wall and what velocity limit one sets.

Approach at a narrow angle and the flow will be along the wall, but there will still be some splashing and the fluid is passing across an air gap. The API practice on static electricity does not increase flow above 1 m/s until the pipe or bottom fill pipe are covered sufficiently to prevent splashing, so should I be doing the same thing?

Lastly if one has an undersized nozzle, can just the curved fill pipe be upsized to lower velocity before it exits the fill pipe onto the wall or must I upsize the nozzle entrance as well.

 

[hacksaw]

keep the velocity low including the nozzle and at the discharge.

you might be able to reduce the charging rate by using a flow deflected against the wall but it does not control the hazard in all circumstances.

the low velocity method is the only one that can be counted on, but even then you have to make certain that all components are properly grounded.

 

[786392]

True,The most important while handling non-conducting flammables is

to ensure 3ft/sec(or 1m/sec) velocity so that 'rate of static charge generation'remains offset by 'rate of static charge dissipation'

Other are

1)Elimination/minimzation of Air/vapor mix generation,

2)Ignition Energy level static charge sinking into ground beds,

3)Elimination through proper bonding of System's electrical insulation/compartmenting.

Filling pipe in physical vicinity to inner side wall may be partly helpful in #1 above.
Hope this helps

Best Regards
Qalander(Chem)