Pipe Sensors and Mag Meters – A Comparison

NIVUS Pipe Sensor vs. Mag Meter

Some time ago, Water Company Directors sought NIVUS to know how the latter can demonstrate savings in AMP 5.

The Story Then Begins…

After viewing the NIVUS pipe sensor, UK Water Company asked, “Could we use your sensor rather than a Mag meter?”, “Yes,” NIVUS replied. “How many £ millions would you like to save by using a proven and efficient solution?”

Engineering and Delivery Managers told NIVUS about the real cost of refitting a Mag meter and why they would like to make use of NIVUS.

The Measurable Benefits

There are several advantages of using the NIVUS solution, such as ease of use, accuracy, cost, time, and low carbon footprint. So as to provide a direct comparison to the usual cost and time implications of conventional Mag Meter replacement, water companies typically incur substantial amounts of costs namely over excavation, pumping, and associated downtime which usually make such projects even more cost prohibitive. Pound for pound, this is a direct cost comparison based upon the real figures provided to NIVUS.

Data provided by UK Water Company Delivery Managers, and not specific to Anglian Water

Above costs based upon a 300 mm pipe application, but larger savings can be realized on larger applications.

NIVUS Cross Correlation Technology

The NIVUS Cross Correlation technology is a patented and ground-breaking ultrasonic flow measurement method. When reflectors are scanned within the water (gas bubbles, minerals, or particles), an ultrasonic impulse is saved as an echo pattern. Extra scans follow milliseconds later. Correlation of all signals enables the measurement of the flow velocity either in full or partially filled applications, displaying the specific flow profile on the screen.

The NIVUS Pipe Sensor

Fully operational installations and field trials have been operating for over three years with accuracies established similar to validated alternatives, with zero failures. Velocity measurement accuracy is ±1% which is unmatched in its field and shows this unit as a realistic alternative to MAG meters.

The meter results are good enough that it will be proposed to be developed into one of the @one Alliance standard products to be used by @one Alliance and Anglian Water.

Peter Caldwell, Jacobs, Part of the @one Alliance working on behalf of Anglian Water

MCERTS Approved

“As part of their MCERTS programme Anglian Water has used both the wedge sensor and the insertion flow meter to great effect. Installing the wedge sensor at one of our sites in Bedfordshire proved to be a simple and cost-effective way of measuring flow as an alternative to replacing a weir or installing an electro-magnetic flow meter which would have taken extended periods of time and site disturbance to install.” stated Oliver Grievson, Flow Compliance & Regulatory Manager, Anglian Water

The NIVUS solution provided a better solution at a cheaper price with a minimum of site disturbance. Anglian Water has also saved money and hassle in using the Insertion Meter for flow meter verification purposes where a "Time of Flight" meter cannot be used. Both the Wedge and the Insertion Flow Meters have given the Anglian Water MCERTS Programme a valuable alternative to the traditional solutions of using ultrasonic and electro-magnetic flow meters.

Oliver Grievson, Flow Compliance & Regulatory Manager, Anglian Water

The Innovation Behind the Product

NIVUS’ Cross Correlation patented technology outshines the competition in terms of accuracy. The pipe sensor (insertion flow meter) has a compact design and serves as a one-size sensor for all diameters. It is engineered for a low carbon footprint and is ideal for full or partial pipes. NIVUS’ unique extraction tool is created for easy insertion and removal. It is built for pipes under pressure and therefore allows little or no site disruption in all situations. When time and cost savings are crucial as is accuracy of data, the pipe sensor becomes the favored option for the validation and/or replacement of Mag Meters.

Cross Correlation, an ultrasonic measurement principle, received its patented status because of the novel measurement technique. The comprehensive profiling of the whole flow provides the required accuracy, which is made possible with this method. The transition of each particle is measured to pass the sensor and data is measured in milliseconds, affording a continuous and extremely accurate flow profile.

We saw a potential benefit from using this technology. We worked together to arrange a trial of a NIVUS insertion pipe sensor to directly compare against a new magflow meter. The trial was at Caister WWTW where we developed comparison data for mixed liquor flows to a final settlement tank. The results showed very good correlation. NIVUS were allowed to use this data as part of their application to gain MCERTS approval for their meter – their channel based meter already had MCERTS approval. The data was used to justify the installation of a NIVUS pipe meter as a magflow replacement that arose on a separate project on the works.

Peter Caldwell, Jacobs

NIVUS Unique Extraction Tool

The NIVUS Unique Extraction Tool can be effortlessly maintained. It is precisely developed for pipes under pressure, enabling easy insertion and extraction of the pipe sensor without having to close the flow.

Case Study

Caister WWTW Anglian Water

To cut into a current main and fit the latest Mag meter with two valves.

• Over pump
• Plant stoppages
• Excavation of site
• Crane
• Four workmen
• Days of site disruption
• Total cost £ 52,000

The NIVUS Solution

To drill and tap into a present main under pressure.

• Strap and fit NIVUS pipe sensor
• Two workmen half a day
• Total cost £ 9,200

Any site preparation costs not included above.

An @one Alliance briefing note and poster were developed and publicized at a sustainability in design drop-in session in September 2012 and were seen/discussed by approximately 100 designers and project personnel. @one Alliance projects for Anglian Water have purchased 10 NIVUS meters in tandem with this development.

Peter Caldwell, Jacobs

Development and Design

The NIVUS meter was in development for a year and was later launched in the market in 2008. It was mostly targeted to challenge the Mag Meter market. The meter was originally launched into the German Market and then into the UK Market after two years. It also won the official MCERTS status in 2012, and today it is progressively being recognized as an ideal solution for the validation and/or replacement of Mag Meters in the UK.

Life cycle costs related to Mag Meter installation and maintenance is comparatively expensive. By heeding market necessities, NIVUS identified the prospect for a removable and more cost-effective flow measurement device for full and partially full pipes that can suit the applications and accuracy of a Mag Meter. The compact design and the sturdy stainless steel outer casing of the flow measurement device are far easier to handle, particularly in confined spaces and matched for diameters ranging from 80 mm.

Positioned at the very tip, the sensor is the only part to sit in the flow and thus decreases any debris or ragging failures with the extra benefit of being self-cleaning. The sensor can be installed to any pipe material, and based on application, can be positioned at virtually any circumference point for an accurate and comprehensive reading.

Based on the NIVUS patented Cross Correlation principle, the pipe sensor does not require calibration. Since it is truly versatile, it can provide flow velocity and/or level accuracy whether mounted, for instance, on a boat system for open channel monitoring and a pipe insertion meter.

NIVUS has built the pipe sensor such that it can be effortlessly connected to the lower priced NFP transmitter, for smaller applications. It also decreases the solution costs. Ease of installation marks the biggest impact of NIVUS product; the comparative installation costs are usually 75% cheaper, which factually saves thousands for the Water sector. A NIVUS pipe sensor can be fitted in just a matter of hours without causing any interruption to the flow, while the Mag Meters are associated with days of site disruption.

Comparing unit prices of the NIVUS pipe sensor versus the Mag Meter, at 300DN for example, pound for pound the sensor is marginally higher than a Mag meter at this size. However, the considerable costs saved on a fast and easy installation mean the NIVUS pipe sensor is always the more cost-effective solution overall, and provides a far cheaper alternative with regards to labor and material on larger applications.

The sensor is available in typical length sizes of 20/30/40 cm. When access space is narrow, extendable rods can be fitted for insertion/removal of the sensor using a guide tube. Furthermore, NIVUS has made maintenance comparatively simple and has developed a modern extraction tool that allows easy removal and insertion of the sensor for pipes under pressure. Therefore, the process does not have to be disturbed.

The NIVUS pipe sensors are built to last for a long time. They are cost-effective, easy to use, easy to maintain, and provide the reliability and accuracy required by Water Companies. Last but not least, comparable studies have shown that carbon footprint can be decreased by as much as 80% by using NIVUS pipe sensors over the more conventional Mag Meters.

This information has been sourced, reviewed and adapted from materials provided by NIVUS GmbH.

For more information on this source, please visit NIVUS GmbH.