The article I read said that there is static pressure inside the short tube that contains the pitot inlet. The static pressure adds to the velocity pressure to give an artificially high gauge reading. This would back up your findings that the hose monster indicated less flow than the diffuser.
Ron Fletcher Aero Automatic Sprinkler Phoenix, AZ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Duross Sent: Wednesday, October 15, 2008 6:39 AM To: [email protected] Subject: RE: FLOW / PITOT READINGS I bought one years ago for a project I bid on ISO testing a town north of Boston (Bahstin). They required it to be used in the contact. Once a year or so later I was using it and the underwriter was present and he wanted more water (wata) flowed. I only had one so I got a monster and hose and flowed another hydrant, much less water from two. He questioned the diffuser so we took it off and put on a monster and 10 foot hose and opened it. Less than the diffuser. I know the monster was working right as I had checked it against a playpipe and flow meter and it had a calibrated gauge. >From that time on, I shelved the diffuser and never used it again. Same with that in-line 2.5" rig they have, gathering dust. My take is it's too close to the opening, not a diameter away and right where the nozzle begins to flare out plus that cheap gpm/psi plastic gauge bounces and I don't know how accurate it is either. I've seen too many instances of bad data used in sizing pumps and what problems that brings and can only imagine what issues it could bring so a simple sprinkler design and nobody would know. It's like building on a cracked foundation imho. Sorry to pontificate, strong coffee today. :) FGOL Tom, Do you know why the Pollards are in accurate? I have read that there is problem with the pitot being inside a short tube. Ron Fletcher Aero Automatic Sprinkler Phoenix, AZ _______________________________________________ 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) _______________________________________________ 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)
