Re: Eccentric Reducers on Pump Suctions Redux - FOT/FOB

From: <sandeep>
Date: Fri Feb 25 2005 - 23:46:00 EST

my take on the situation is as follows
recommendaton for FOB when the fluid is coming from TOP may be to avoid fluid accumulation in the horizontal portion of the pipe i.e. in the event one has an FOT in the above mentioned configuration process fluid accumulation will be there by virtue of the eccentricity / sloping side on the bottom

btw: PSV installaton in the horizontal is acceptable as per ASME sec VIII, however due considerations have to be given to condensate draining.(this query i had floated a while back)

sandeep

   These two sites contradict each other; McNally Institute says FOT at    pump suction and The Pump Handbook (via Fluide Design) says it should be    FOB. Any comments out there? Could the Pump Handbook actually be wrong?

   http://www.mcnallyinstitute.com/CDweb/p-html/p015.htm

"Make sure eccentric reducers are not installed upside down at the pump
   suction. The top of the reducer should go straight into the suction flange."

"Use eccentric reducers rather than concentric reducers at the pump
   suction. Concentric reducers will trap air. Be sure the eccentric    reducer is not installed up side down."

"Be careful to install the eccentric reducer with the straight side up
   to prevent trapping air at the pump suction."

   http://www.fluidedesign.com/download-free/guidel_pump_syst-extract.pdf

"Always use an eccentric reducer at the pump suction when a pipe size
   transition is
   required. Put the flat on top when the fluid is coming from below or    straight (see
   Figure 1) and the flat on the bottom when the fluid is coming from the    top. This will
   avoid an air pocket at the pump suction and allow air to be evacuated."

   [This text is followed by a graphic showing a *flat-on-bottom* eccentric    reducer directly connected to a pump suction with suction line coming in    from the top (as if feeding the pump from a piperack). The image is    credited to "The Pump Handbook published by McGraw-Hill.]



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[Non-text portions of this message have been removed] Received on Fri Feb 25 23:46:00 2005

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