Jul 07, 2015

It All Adds Up

Flowmeter corrects inaccurate flow rates at West Virginia booster station

McCrometer FPI magnetic flowmeter Buckhannon West Virginia

Kelly Arnold, distribution supervisor, and Jay Hollen, city engineer, for the city of Buckhannon, W.Va., recently ran into a situation that did not add up. A flowmeter at one of the city’s booster stations was indicating a flow rate higher than the capacity of the station’s pumps.

“Installing the new McCrometer FPI Mag flowmeter confirmed what we already knew: The old meter was showing a flow rate of 450 gal per minute or more, but we were actually pulling only 350 gal per minute. The old meter was showing a flow rate much higher than the capacity of the pumps at the booster station,” Arnold said.

The flowmeter causing the problem was an older full-bore mag meter. Whenever recalibration of the meter was necessary, the line had to be shut down, a whole section of pipe needed to be removed and a new meter had to be installed.

“Having to pull out the old meter would have involved an $8,000 investment to remove it [and] send it in, and required buying a new in-line meter to make sure operations could continue,” Arnold said. “Going with the FPI Mag flowmeter was a much bigger savings in terms of downtime and costs.”

Inaccurate Measurements

The city of Buckhannon lies along the scenic Buckhannon River, northeast of the state capital of Charleston. The city’s water department serves a population of about 22,500 residents in the region, providing the “best drinking water” in north central West Virginia, according to the West Virginia Rural Water Assn. The city’s water treatment plant utilizes water from the Buckhannon River, which also is an important outdoor recreational asset and tourist attraction in the area.

At the city’s Tennerton booster station, the staff routinely monitors how much water is pumped through the station to a nearby public service district (PSD) and another area where there is a different pressure zone. Those data are used to determine if there are any leak problems by subtracting the PSD meter’s flow rate from the Tennerton station’s flow rate. 

“The FPI Mag meter serves as a totalizer at the booster station to monitor the flow through the pumps to ensure the system is operating efficiently,” Arnold said. “If we see excessive usage, then that indicates a problem and we have to address it.” 

Hollen added that it was important to resolve the inaccurate flow reading issue because not only was the city receiving inaccurate flow data, but it also was considering upgrading the pumps at the booster station based on increased demand.

“We need to have the most accurate flow reading information available to ensure that the correct pumps (as far as output is concerned) are selected,” Hollen said.

The department’s staff regularly compares how many gallons per minute its pumps are drawing, which is what led to the suspicion that the old full-bore meter was inaccurate. The data help them spot leaks and other issues before they cause major problems. Arnold noted that a few years ago an underground leak near the local high school went undetected for 18 to 20 hours, resulting in a lot of wasted water and high operational expenses.

A Simple Solution

The Buckhannon city staff contacted the applications team at McCrometer about its flowmeter accuracy problem. The team recommended the FPI Mag flowmeter, which was designed to deliver consistent, accurate results within the challenging flow profiles of the booster station. Featuring a hot tap design for easy installation and removal, with low maintenance requirements, the flowmeter fit the city’s need. 

The installation process at the booster station was simple, with the insertion of the FPI Mag meter taking less than one hour. If the city had pulled the old meter out and replaced it, Arnold explained, the booster station could have been down for as long as four to six hours.

“We would have had to take the pipe completely apart to remove the old full-bore meter,” Arnold said. “It was a whole lot easier just to insert the FPI Mag meter. With the new insertion-type FPI Mag meter, our system can remain up and running.” The meter data also serve as an accurate basis to cross-check with other system processes to provide reliable operations status.

“I see more advantages to using the FPI Mag meter. You can quickly hot tap into the pipe for installation, so there’s less downtime. It’s also easier to retrieve for maintenance,” Arnold said. “If there’s a need to shut it down, we can get it back in service right away. This meter is doing a really good job. It’s going to save us money over time.”

Understanding the Technology

With the city staff’s commitment to high-quality drinking water, the flowmeter’s design solved an important operational problem at the booster station. The meter’s advanced sensor features multiple coils and electrodes assembled in a tube that inserts completely into the pipe to measure the full profile of the flow stream, providing accuracy even in challenging flow conditions.

The meter’s signal converter features an advanced filtering algorithm to support accuracy of ±0.5% of reading from 1 to 32 ft per second and ±1% from 0.3 to 1 ft per second. The signal converter also includes built-in dual 4-20 mA outputs for communication flexibility, additional programmable outputs to support SCADA systems and a simplified menu structure for ease of use. These features make it easy for any city staff member to connect the meter to the facility’s monitoring system.

With no moving parts, there is nothing to wear or break with the FPI Mag flowmeter. No recalibration in the field is necessary. The sensor body is made from heavy-duty 316 stainless steel for maximum structural integrity. The sensor body is hermetically sealed and protected by an NSF-certified 3M fusion-bonded epoxy coating.

Arnold said everything adds up now in terms of flow rates at the Tennerton booster station with the new flowmeter. The Buckhannon city water department staff is pleased with the meter’s accurate performance and simple installation. “The way the meter measures reliably, combined with its hot tap insertion design, makes it a whole lot more dependable and easier to maintain,” Arnold said.

The meter will be considered the next time the city purchases a new meter. “We replaced another meter not long ago, and if we had known about the FPI Mag meter at that time, then I’m sure we would have looked really hard at that as an option,” Arnold said.

“There have even been discussions with our water treatment plant about the installation of an FPI Mag meter on our high-service pumps’ discharge lines to more accurately determine the amount of potable water being distributed throughout the system,” Hollen said.

About the author

Greg Corrins is sales engineer for Daman Superior. Greg Webster is technical staff for McCrometer. Webster can be reached at [email protected].

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