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North Carolina civil engineering firm upgrades flow-monitoring devices

Frazier Engineering is a civil engineering firm that serves customers in the Carolinas, Virginia and Tennessee. It has more than 18 years of experience in collection system flow monitoring. In addition to flow monitoring services, Frazier provides sewer system planning and design, as well as sanitary sewer rehabilitation redesign.

When new flow monitoring equipment was required to update Frazier’s fleet, it selected Hach FL900 Series flow loggers.

“When some of our oldest Sigma meters required extensive repairs, we made the decision to replace them with FL900AV flow loggers,” said Mark Lambert, project manager for Frazier. “So far, we have purchased 25 new flow loggers to replace Sigma models 920 and 930 meters.”

The new loggers will be used in pipe sizes ranging from 8 to 48 in.

Lambert has been in the flow business for 23 years, including roles as both a consultant and a municipal employee. He feels that Frazier Engineering’s flow business has grown for a number of reasons, including flow monitoring expertise, flowmeter repair capabilities and extensive data interpretation and site selection experience.

“There are so many things that can go wrong in flow monitoring, and our customers rely on us for our expertise,” he said.

Newly purchased Sigma AV sensors, as well as existing Sigma AV sensors in its stock, were used with the new loggers. Frazier’s existing flowmeter fleet is comprised of 78% Sigma/Hach flowmeter systems and is a mix of both wireless and nonwireless Sigma AV and FLO-DAR AV sensors. Client flowmeters are installed and maintained by Frazier Engineering field crews.

The Hach FL900AV flowmeter was designed for users desiring in-depth analysis and custom settings. The diagnostic tools and advanced architecture in the Hach FL900AV flowmeter with the AV9000 analyzer module make it possible to acquire useful flow data at difficult sites. It provides cleaner, more precise data than ever before with advanced signal processing and filtering options, expanding the applicability of submerged AV sensors into more difficult applications. The AV9000 area velocity analyzer module is compensated for temperature, thus eliminating potential velocity errors that occur during seasonal temperature changes. Its advanced multiscale digital Doppler analysis provides a combination of resolution and noise immunity. Mirror Image Processing eliminates sign errors, and the advanced Target Set Processing reduces the impact of dominant targets (particles) in the stream to deliver a more representative velocity. FLO-WARE data management software is compatible with the system as well as the FSDATA online data manager website for wireless applications.

One of Frazier’s clients with newly installed FL900AV loggers is the Water and Sewer Authority of Cabarrus County (WSACC), located in Concord, N.C. Some of the meters used in this application are master billing meters.

“In the past, we had problems with the old Sigma 920 and 930 meters in one of their low flow sites,” said Lambert. “They just weren’t giving good data. After installation of the new Hach FL900AV flow meter in the same low flow site the data is so much better. We are seeing a much better diurnal pattern and the sensors don’t seem to drift.”

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