Discovering Irrigation Leaks With Ultrasonic Flowmeters
The FLOMEC® QS200 is designed to support commercial irrigation applications and measures flow rates three times lower than current flow sensors on the market—as low as 0.83LPM while providing extended leak detection down to 0.03m/s. The City of Fontana found out just how critical these features are when an irrigation system blockage went undetected until the installation of the QS200 flowmeter.
The city of Fontana has a population of around 200,000 people with many vegetated traffic islands and median strips. Located in California, they have suffered severe droughts in recent times, and the conservation of water and the maintenance of valuable trees and shrubs in public spaces has been a major concern. The annual water usage budget for the city is $250,000.
The city officials were monitoring the water usage in bubbler nozzle irrigation in many green traffic islands with paddle wheel flow meters attached to a remote alarm system to indicate a ‘no flow’ situation. They had turned off the alarms from the paddle wheel meters because they were giving false positives; showing no flow when it was below the threshold of the meter to sense.
The paddle wheel meters have a glassed reinforced nylon impeller that requires enough flow velocity to overcome the friction of the wheel on the shaft to show any flow. The ultrasonic QS200 has no moving parts and requires much lower flow rates to register a reading and is retrofittable into the existing housing for most meters supplied with Rainbird, Hunter, and Toro irrigation systems.
The City trialed the FLOMEC QS200 in a single installation with bubbler head irrigation with flow below 8 L/min, retro fitting it in the existing housing. The low flow alarms were reset for the QS200 Ultrasonic flow meters. A low flow alarm from the QS200 was thought to be another false alarm, as had occurred previously with the paddle wheel meters. When the alarm was investigated, it was found that there was a blockage in the nozzle and no water was reaching the meter or plants.
The ability of the meter to detect low flows, typical of bubbler and drip line water velocities, saved the city the cost of replacing a whole median strip that had been vegetated; an expensive and difficult job when complicated with traffic flow. Savings were estimated by the City of Fontana Engineer in the thousands of dollars.
"Municipalities that rely on commercial irrigation are under increasing pressure to control their usage and costs. We engineered the QS200 to address that need.
Traditional paddle wheel sensors often used by utilities can't read the low flows required in many irrigation applications. This limits their ability to detect system leaks. Blockages can go undetected because 'no flow' warnings are attributed to flows below the ability of the sensor to actually sense." - Mark Bieberle, Meter Product Manager.