You're right Rahe, flow must be modulated after the venturi or pretty much any other flowmeter including the ones I use. Mine have a transducer paddle wheel (like a boat's speedo) that spins on flow once programmed to the size of the pipe. One additional bonus to these is they can be programmed to read between any pipe size from 1" to 10", can be calibrated to 1 to 3 points, can total the flow used and be programmed to read single digits, increments of 5 or 10 or whatever and also to read in different increments at different flow rates. I have Powhaton globe valves on the discharge end of the tubes, I've found them to be the most able to adjust and hold a setting while flowing. I have mine read in increments of 1 up to 300 GPM and then switch to increments of 5 to 750 and them light an overlimit signal above that (accuracy fails at 800+ with a 2 1/2" size).
Tom Duross The real problem with flow meters is that there has to be a true laminar flow through the venturi to be even close to accurate and that the flow meter has to be calibrated before any testing can be done through it per NFPA 25. If you have ever tried to measure flow through one of the commercially available flow meters, you will find yourself trying to guess or average the jittery needle movement. They are not as accurate as a pitot gauge when calibrated and properly used. In my jurisdiction I do not allow them to be installed or used for flow testing. Thank You Rahe Loftin, P.E. Chris the only "In-Line" Flow meter we've used is on fire pumps and we use the Victaulic Style 735 (Sizes 2.5 to 10" 500Psi max) Thom McMahon _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
