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[jango]

We recently increased the flow to our decanter centrifuge to 220 L/min. The liquid discharge line is currently 3", which results in a Froude number of approximately 1. I suspect that this high Froude number is causing air entrainment and flow surging.

To mitigate this, I am considering increasing the pipe size in the horizontal section (approximately 7 m long) from 3" to 5", which would reduce the Froude number to about 0.22 (<0.3). My proposal is to keep the vertical section and dip pipe (about 5 m downward) at 3" diameter.

My rationale is that:

• The larger horizontal section will help vent any entrained or dissolved air.

• The vertical downflow section should remain liquid-full, so a 3" diameter should be sufficient.

Does this approach make sense? Are there any potential issues with transitioning from 5" back to 3" before the vertical section. The location of the transition is it better to do it at the end of the horizontal line, start of the vertical line or bend? I have attached a sketch for more info.

Thank you!

[breizh]

Hi,

Share with us your sketch,

the document in reference has a typo, sign minus in front of equation 5.

Did you talk to vendor? they should be able to support your query.

It may not be a single cause. Process issue? Mechanical issue? 

Breizh

Attached Files

•  Hill Gravity flow.pdf   2.94MB   0 downloads