New Generation of Water Meters Offer Increased Accuracy

Until recently, water meters have been quiet workhorses, operating for decades without fanfare. In the meantime, dramatic technology leaps have been made in other areas, such as automated meter reading (AMR) and advanced metering infrastructure (AMI) systems for remote meter reading and monitoring.

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By Doug McCall

Until recently, water meters have been quiet workhorses, operating for decades without fanfare. In the meantime, dramatic technology leaps have been made in other areas, such as automated meter reading (AMR) and advanced metering infrastructure (AMI) systems for remote meter reading and monitoring.

As water utilities face rising costs of labor and energy while revenues are decreasing, they are seeking new options to improve operational efficiency and save time and resources. Now these utilities are able to turn to recent advancements in metering technology that help utilities meet operational efficiency and revenue goals and customer service expectations.

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A lid-mounted antenna aids in wireless communication.

With new metering technologies, utilities can reap benefits including additional revenue protection over the long term and decreased operational costs recognized immediately. Recent breakthroughs in metering technology are making once unheard of measurement accuracy accessible at very low and high flow rates.

Floating Ball Technology

Floating Ball Technology (FBT) is a variant on turbine metering that significantly reduces pressure loss and virtually eliminates component wear while improving accuracy across an extended flow range.

FBT is characterized by a ball-shaped, turbine impeller that floats between axial bearings in the measuring chamber of the meter. Water passes through the meter, causing the turbine impeller to rise from its bearings and rotate in the water. As this occurs, embedded rotor magnets deliver signals to an ultra-sensitive register pickup probe. As flow increases, the impeller centers itself and literally floats inside the measuring chamber.

The thermoplastic ball is virtually weightless in water, therefore even the smallest changes in flow cause the impeller to rise and fall accordingly. As a result, this type of meter can accurately record very low flows as well as support extended high flow rates – all with practically no friction or wear.

Remanent Field Technology

Another common meter type is magnetic flow meters, which measure an electrical signal that is produced when ionized water flows through a magnetic field. The faster the water flows, the more voltage is created and measured. Voltage is linearly proportional to speed; as water speed increases, voltage increases and the measure of volume increases.

Similar to positive displacement meters, magnetic flow meters are fairly accurate, but the magnetic field required to gather accurate measurements requires a great deal of energy.

On the other hand, remanent field technology, in conjunction with magnetic metering technology, requires far less energy than traditional mag meters and permits much greater accuracy, even at intermittent or very low flows.

Traditional metering technology uses electrical current flowing in a drive coil to create the magnetic field. Remanent technology, with its low switching rate and patented electrodes embedded in the flow tube, maintains a magnetic field without continuous battery drain. As the energy efficiency of water meters increases, the amount of money the utility must spend on this resource simultaneously decreases.

Benefits

Preventing nonrevenue water loss will deliver meaningful new revenue and more accurate customer billing. In light of these benefits, utilities should make low-flow and high-flow accuracy a key consideration when evaluating meters.

For meters employing FBT, the slightest amount of water will cause the lightweight impeller to move. This captures flows up to 50 percent lower than the lowest flow measured by traditional turbine meters. FBT also enables meters to register reads at higher flow rates than traditional turbo meters.

Because meters built with remanent field technology measure intermittent flow, they are far more accurate than traditional mag meters, which typically sample at intervals and average results. Continuous sampling in mag meters is possible but requires an undue amount of power. Compared with PD meters, remanent field meters can measure up to a 20 percent lower flow rate and withstand high flows while maintaining measurement accuracy.

Cost of Ownership

Since newer metering technologies have zero or few moving parts, there is a lower total cost of ownership including the cost to install, operate and maintain meters. There are fewer individual components to maintain, and since there is less wear and tear on the meter it will have a longer, more accurate service life. The new technologies eliminate the biggest headache of a meter shop: the parts stocking and repair costs involved in maintaining traditional water meters.

In addition, since newer metering technologies capture more flow for more revenue, there is a faster return on investment than with legacy technologies.

Newer metering technologies also have little effect on water pressure, and therefore reduce head loss. By reducing pressure loss relative to traditional meters, less energy is required to achieve acceptable water pressure at customer premises. This means less pumping, more accurate infrastructure design and ultimately lower electricity bills and capital budgets.

Monitoring

Intelligence from meters including remote notification of leaks, tampering, out-of-threshold operating conditions, low battery and more enables utilities to be proactive. Utilities can alert customers to an issue before the customer is aware or before any damage occurs and quickly identify, troubleshoot and resolve field issues.

Globally, water is a precious commodity, to be used and conserved wisely. Leaks in the water distribution system or at customer sites represent not only lost water, but wasted energy to pump it for no purpose.

Traditional meters do not do a very good job of detecting and measuring ultra-low flows. Even if they are equipped for ongoing AMI communications, they could miss the very low flow levels that signal a leak. Newer metering technologies are sensitive to low flows and are therefore more reliable for detecting and reporting leaks.

Future of Water

New flow measurement technologies offer the opportunity for meters to deliver real business benefits – cost savings and new revenues – as well as competitive differentiation.

For water utilities, new metering technologies can drive additional revenue, sustain high accuracy across their operating range and throughout the life of the meter, reduce energy costs associated with pumping and streamline and reduce costs associated with meter installation, operation and maintenance.

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New metering technologies offer improved measurement accuracy at very low and high flow rates.

For utility customers, these advancements offer improved water system performance and reliability, and enable more equitable and flexible billing options due to higher meter accuracy, continuous measurement and compatibility with AMR/AMI systems for on-demand data.

Water utilities are met with more challenges than ever, but they are also faced with more opportunities. A new generation of water meters will, when conjoined with intelligent water management systems, enable utilities to improve their operations while meeting increasing customer expectations and global conservation initiatives for decades to come.

Doug McCall is the director of marketing for Sensus and has been with the company for more than ten years. He may be contacted at doug.mccall@sensus.com.

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