Village of Baltimore Ohio Finds "Fantastic" New Flowmeter

Personnel at the Village of Baltimore, Ohioâs Wastewater Treatment Plant are not strangers when it comes to procuring progressive open-channel flowmeters. In fact, in the early 1990âs when the municipality had a requirement to purchase flow monitoring equipment for their Inflow and Infiltration (I&I) work, they selected flowmeters manufactured by Marsh-McBirney, Inc. At that time Marsh-McBirney was known worldwide for the Flo-Tote flowmeter innovation that revolutionized open-channel flow monitoring. The Flo-Tote was the first area/velocity open-channel flow monitoring device to electronically record flow data. The flowmeter included an electromagnetic sensor/mounting band assembly that was installed directly in the flow stream. The ever-popular Flo-Tote flowmeter has undergone numerous customer requested upgrades throughout the years and today is marketed under the name Flo-Tote 3. While the use of submerged sensors generally poses no operational challenges in most monitoring applications, the potential does exist for sensor fouling by debris in the rugged sewer environment as well as increased expenditures for confined space entry labor and equipment necessary to install and remove the sensor.

Lowell Clugston, Operator for the Village of Baltimoreâs Wastewater Treatment Plant, has worked with the Flo-Tote flowmeters for many years and understands the compromises of monitoring wastewater flow using submerged style sensors. When his local MMI representative, Chesley Associates, introduced him to Marsh-McBirneyâs latest flowmeter innovation, the Flo-Dar flowmeter, he and other plant personnel decided it was once again time to upgrade to the industryâs newest flowmeter trend. In May 2002, the portable, battery-operated version of the Flo-Dar flowmeter family of products was selected for their I&I work.

The Flo-Dar flowmeters provide a revolutionary approach to open channel flow monitoring - combining non-contact velocity and depth sensing technologies to remotely measure open channel flows. Flo-Dar transmits a digital doppler radar beam that interacts with the fluid and reflects back signals at a different frequency than that which was transmitted. These reflected signals are compared with the transmitted frequency. The resulting frequency shift provides an accurate measure of the velocity and the direction of the flow. Level is detected by ultrasonic pulse echo. Flow is then calculated based on the Continuity Equation:

Q = V x A, Where Q = Flow, V = Average Velocity and A = Area.

In addition, Flo-Dar provides the user with highly accurate flow measurements under a wide range of flows and site conditions. By measuring the velocity of the fluid from above, Flo-Dar eliminates accuracy problems inherent with submerged sensors including sensor disturbances and high solids content found in Baltimoreâs wastewater flows. Flo-Dar is also ideal for high temperature flows, caustic flows, large man-made channels, high velocities and shallow flows.

Personnel have no contact with the flow during installation and maintenance issues caused by sensor fouling are eliminated. The meter does not require profiling allowing for added proficiency in site-to-site monitoring. The sensor and monitor are also field replaceable and interchangeable with the new Flo-Tote 3 flowmeter.

Clugston states that they are moving the new meter from site-to-site in primarily residential areas. When asked about the meterâs performance he answers in a word, 'fantastic.ä  He also adds, 'The increased battery life and quick installation with the jack-bar assembly are features that stand out for me.ä  The fact that the sensor is within the operatorâs sight line was also a plus for Baltimore WWTP personnel.

With the addition of the Flo-Dar meter to Baltimoreâs I&I monitoring program they are confident that they have chosen the industryâs newest and best flowmeter innovation. The Flo-Dar meter will streamline their I&I efforts by enabling them to quickly and easily identify potential maintenance issues including line surcharges and potential overflows within their sewer system for many years to come.