I think that eccFOT will work in all cases will work since if gas accumulates at
the top of the flat it will eventually move through the pump and be eliminated.
If you use the ecc.FOB when fluid is coming from above it gives you the
opportunity to eliminate the gas right from the start, in fact no gas can
accumulate at the pump suction since it will normally rise up out of the suction
pipe. Gas can be very hard to get rid of when it collects in flat spots this
eliminates any collection possibility.
Jacques
www.fluidedesign.com
My point is that the fluidedesign.com image excerpt from "The Pump
Handbook" contradicts most other sources when it comes to flow coming
into a centrifugal pump from above and the proper orientation
installation recommendations for an eccentric reducer on a pump suction
(FOT vs. FOB).
Where is entrained air/vapour going to collect after extended operation
in the visual scenario proposed by Figure 1 at
http://www.fluidedesign.com/download-free/guidel_pump_syst-extract.pdf ?
I'm assuming that there will be some turbulent flow characteristics due
to the change in direction through the elbow (and also any upstream
combination of X-Y-Z axis piping) and that air/vapour would naturally
collect in the high "cavity" point of a FOB reducer. Then, this
collection of air/vapour could slowly impinge on the impeller or let
loose all at once. This IS fluid dynamics analysis, so event prediction
is one of those things that cannot be reliably measured.
Am I wrong in my interpretation or am I going straight to pump hell for
being a heretic (or, even worse, condemned worldwide as being a moron in
the piping design community)?
Maybe some inexperienced draftsman made a drawing mistake and it wasn't
caught by the editors for all these years.
And as usual, I'll add the caveat that I'm just asking questions since
the only dumb question (within reason) is the one you didn't ask.
Paul
Jacques Chaurette wrote:
> The Pump Handbook actually recommends both situations, depends on whether
the fluid is coming horizontal or from the bottom (FOT) or if it is coming from
the top (FOB).
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[Non-text portions of this message have been removed] Received on Sat Feb 26 08:16:00 2005
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