Buried flow meters for lowest installed cost
Many seasoned water professionals may throw their hands skyward at the mere suggestion of burying flow meters underground. They will more than likely remember the manufacturer promises made a decade or more ago, when meters were buried in their dozens. However, after frequent reliability issues and the challenges of retrieving buried inline meters, many of these industry C&I experts said, “enough is enough; no more buried meters”!
Which is a shame. Because burying clamp-on flowmeters can undoubtedly achieve significantly lower installed costs than building substantial chambers with all the associated rapidly escalating costs for bypasses, isolation valves, supply interruptions, etc…as long as they can be proven reliable. And clamp-on is substantially easier to maintain from outside the pipe than removal of an inline meter.
In the UK, FLEXIM has been proving reliable use of its MCERTS clamp-on F721WD flowmeters for nearly 6 years, and for significantly longer in Europe where water municipalities have been burying FLEXIM meters in countries such as Germany, Austria, the Netherlands, etc as a matter of course for decades.
The F721WD flow meter has a Mean Time Between Failure (MTBF) of 36.9 years and when equipped with IP68 transducers and solid transducer coupling pads (no gels or greases to dissipate over time), can be relied upon for long-term buried installation at absolute minimum cost. For added peace of mind, it is advisable to bury dual-channel meter transducers; in the unlikely event of a transducer failure, the second channel will remain working and negate the need to unearth and repair the meter.
FLEXIM has installed countless wastewater meters, most commonly for Sewage Pumping Stations, where the meter is simply back-filled with pea-shingle.
One major forward-thinking UK water company, having experienced buried FLEXIM meters on wastewater, decided to adopt an innovative low-cost “Coffin” chamber design for network clean water installations. This involves the meter being installed in an excavated pit and a highly cost-effective “Coffin”chamber being built around the installation before earth is back-filled to the compact chamber walls and capped off with a cast iron cover. This reduced-cost installation, enables more meter installs within the fixed available budget.
IP68 flow meters for installation in flooded chambers
In both prior examples, transducers are supplied IP68 rated, allowing installation where ground water could eventually saturate the soil or shingle around the buried meters.
These same IP68 design transducers can equally be used with solid fluoroelastomer coupling foils (no coupling grease or gels) for high-longevity, zero-maintenance use in flooded chambers or pits.