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Posted by Bob D. on March 25, 2004 at 08:52:28:
In Reply to: I'm Smiling... posted by Amy on March 23, 2004 at 14:12:21:
Over the past, well let's just say many, years, most of the new plants I've built (10-12) have had VSD BFP controls (excepting the really small ones, say <1000 BHP, <= 15 PSI) and I've retrofit maybe another dozen or so. The pumps and motors run cooler, energy use and demand is lower, maintenance intervals are longer, and there are fewer hunting/tuning problems with 2 element drum level controls. It's money in the bank. The thing to remember is that the pump curve MOVES. The whole freakin' thing becomes dynamic. Yeah, retro-fits can be tricky, and you've got to know when a pump simply cannot be run at lower speeds (seals, bearings, thrust, shaft deflection, balance of system, etc.) but for the most part it's not too tough. One or two "aw sh**s" (on your own dime) and you pretty much figure it out (not that it's ever happened to ME . . .). Besides, it's an open forum, the short and sweet answers and advice are worth what what they cost. Keep smilin'.