I have a picture of a hollow stream. It is from a 3/4" pipe (the inspectors test, without an orifice), and shows a piece of trash stationary in the stream. On examination afterward, the trash seemed to be the remains of a cocoon. I can send the pic to anyone interested.
Ed On Tue, Jun 23, 2009 at 1:52 PM, Ed Kramer <[email protected]> wrote: > In theory, the two flow graphs should be identical. In reality, they > should > be reasonably similar. As others have pointed out, the source of the water > (purely gravity vs gravity w/pumps) and pressure reducing devices can > really > confuse things. > > A few observations: a) Unless the flow is very high, pitot readings from a > 4.5" outlet can be very wrong. On several occasions, I've seen hollow > (literally) streams coming from the 4.5". When the pitot was placed in the > center of the outlet, the reading was zero. To get a reading, had to move > the pitot toward an edge. Got a reading, but it grossly overestimated the > actual flow. b) If the 2.5' outlet flowed anything close to the combined > sprinkler/hose demand, use those numbers. c) I wouldn't trust any pitot > reading less than 10. If necessary, connect a smaller orifice to the > outlet > - the flow will be less but the pitot reading will be greater. d) a > single-hydrant flow test is not recommended procedure, but if it can't be > avoided, the results tend to be conservative. > > Curious - what are the exact numbers you're working with? > > Ed Kramer > Littleton, CO > -- Ed Vining 4819 John Muir Rd Martinez CA 94553 925-228-8792 _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
