Ultrasonic Flow Meters – The Development of Clamp-On Flow Meters By Katronic

Published 17 Jan 2017

  • By Chris Dodds : estimated reading time 10 minutes

Ultrasonic Flow Meters

A Technology Coming Of Age

Katronic - Ultrasonic Flow Measurement & Flowmeters

Ultrasonic Flow Meters

Andrew Sutton, Managing Director of Katronic investigates the improvement in technology and increasing use and acceptance of ultrasonic flow meters in a wide variety of industrial and hazardous area flow measurement applications.

Before looking into the progress of one specific flow meter, it is important to recognise that ‘ultrasonic flow measurement’ is a term that covers a considerable range of different products.

Firstly, it should be considered that the measurement of flow using ultrasound can be achieved in two different ways. Some flow meters are based on a Doppler-type ultrasonic measurement technique whereby flow is obtained by looking at frequency changes in ultrasonic signals caused by particulate in the flowing media.

Devices of this nature can be used for measurement on closed pipes, open conduits or rivers where they can also be operated as profiling devices.

The second family of products employ variations of the transit time measurement principle through which the flow velocity is calculated. They interpret the time differences in upstream and downstream pulses sent and received from pairs of ultrasonic transducers.

This style of instrument operates on full pipelines and was traditionally used for clean process fluids. However, as will be discussed later, this is no longer the case.

The third group of products make use of ultrasonic level technology to measure the flow in open channels and are very common in the wastewater industry.

There is additional segregation of the technology as the transit time principle can be applied in two different ways.

In the first instance, pairs, or multiple arrays of ultrasonic transducers are built into measurement spools or inserted directly into pipes to provide a highly accurate measurement of liquids or gasses.

The second variation of the technology – and the one that we will be focusing on is based on the use of non-invasive ultrasonic sensors which are mounted onto the outer surface of the pipe and which remove the need for the user to make modifications to previously installed pipework.

Ultrasonic Flow Meters - The Development of Clamp-On Flow Meters By Katronic

Figure 1. The New KATflow 170 From Katronic Is Typical Of A New Generation Of Clamp-On Flow Meters Offering Customers Greater Levels Of Performance And Reliability.

Inline ultrasonic flow meters were adopted more quickly and are now considered accurate and reliable to the point when used on fiscal flow measurement applications.

In contrast, clamp-on equivalent technologies were traditionally employed for niche requirements rather than as a conventional measurement technique.

It is probably only now after 30 years of use, that customers are learning to trust and accept the instruments as a standard solution.

Ultrasonic Flow Meters



Misapplication & misunderstanding

The path of the clamp-on ultrasonic flow meter from niche product to accepted measurement technology has not been simple.

Initial concerns about reliability caused customer wariness about its use and operation.

There was also the suggestion of the clamp-on flow meter being the instrument of last-resort where, for reasons of complex process conditions alternative flow meters had been considered and rejected leaving the ultrasonic meters as the only possible solution.

This misapplication of the technology led customers to ignore good installation practice in the hope of a successful outcome and placing the blame for unsatisfactory results on the flow instruments.

Fortunately, this is no longer the case as technological developments have allowing manufacturers like Katronic to develop reliable and accurate instruments that meet the needs of its customers.

When looking at the operation of an ultrasonic flow meter, it is important that the customer has a realistic level of expectation and that the manufacturer ensures the technology is correctly used.

Given that the flow meters are properly specified, there is no reason why they should not provide the customer a cost-effective, hasslefree solution across a range of measurement requirements.

Ultrasonic Flow Meters - The Development of Clamp-On Flow Meters By Katronic

Figure 2. Clamp-On Ultrasonic Flow Meters Use Sensors To Send And Receive Ultrasonic Pulses. The Difference In The Time Of The Upstream And Downstream Pulses Is Directly Proportional To The Flow Velocity, Which Is Then Integrated With The Pipe Dimensions And Flow Profile Correction In Order To Provide The Measurements.

One technology, two uses

The clamp-on flow meters remain unique in that they are able to provide users with two distinct measurement solutions from the same standard technology.

Only ultrasonic meters can offer reliable flow measurement that can be moved between locations and take numerous flow measurements in a short period of time.

The same core system can also be employed for permanent installation on pipes with the identical level of ease of use and operation.

The difference in the use of these instruments could be best described by stating that portable flow meters are for identifying problems through testing and fault-finding, and that permanent clamp-on flow meters are used for solving problems.

In this case, the meters would be installed for measurement in locations where a need for a flow meter is proven and meters are not already in place.

Katronic have two portable flow meters to best meet the needs of their customers.

The KATflow 200 is a simple to use lightweight hand-held flow meter as opposed to the more advanced KATflow 230, which is designed to be able to offer engineers a variety of different configuration options.

There is equal diversity on the instruments for permanent installation with three different configurations being available from the lower-cost KATflow 100 to the highly developed KATflow 150 and the new KATflow 170, an ex-certified flow meter for operation in hazardous areas.

Diversification & standardisation

The growth in the use and acceptance of clamp-on ultrasonic flow meters has come about through two different driving factors.

The fact that the transit-time flow meters are mounted on the outside of the pipe has meant that they have always lent themselves to unusual applications.

There are obvious benefits to a meter that can be installed on toxic aggressive and dangerous applications without compromising the systems or risking the safety of personnel.

To give an indication on the breadth of uses that can be found for clamp-on ultrasonic flow meters Katronic are presently working on a project for the installation of KATflow 100 flow meters in space, and have also supplied instruments for submarines.

The meters are utilised in purified non-conductive fluids in the pharmaceutical industry and are equally suited for sewage in the wastewater sector.

This in itself is testament to how far the technology has evolved.

In the past, heavier effluents and sludges would only have been suitable for measurement with a Doppler flow meter whereas now transit-time flow meters are able to provide reliable results.

The real change in the use of the clamp-on flow meter has come in the standardisation of the product with clamp-on instruments now being specified as a direct alternative for more traditional flow meters for reasons of simplicity, cost and commercial justification.

Use in industrial applications

One example of how clamp-on flow meters have found their way into the mainstream is the new KATflow 170 from Katronic.

This instrument is specifically designed for the petrochemical and offshore industries where reliability and robustness are the key concern of the end user.

The hazardous area Zone 1 ex-certified flow meter is available in both stainless steel and epoxy-coated aluminium alloy and can be retrofitted onto pipes greater than 5 metre in diameter.

The flow meter can be used to measure a range of process fluids and is trusted for diverse applications.

One location where the KATflow 170 has found popularity is on oil blending systems – the Katronic meters are needed to provide reliable data on the crude oil flows and are specified by Cameron, a Schlumberger company.

Hazardous Area Flowmeters - Oil Blending

Image: Cameron is a leading international provider of sampling and blending solutions for the oil, gas and hazardous area industries.

As Cameron themselves state “crude oil blending equipment is designed and selected to ensure minimum pressure drop and maximum reliability”.

It is for this reason that the KATflow 170 was used as the clamp-on design delivers stable and dependable measurement with no reduction in system pressure.

Another area where there is a potential for considerable growth on the use of the new technology is on large distribution pipelines, where the non-invasive nature of the flow meters provide a highly robust and cost-effective alternative to invasive Instruments on pipes containing a variety of petroleum products.

Ultrasonic Flow Meters - The Development of Clamp-On Flow Meters By Katronic

Figure 3. Clamp-On Flow Meters Provide The User With The Unique Functionality Of A Genuinely Portable Measurement. Seen Here The KATflow 200 And Transducers In Operation.

In addition, due to the advanced diagnostics found in the KATflow 170, it can offer the customer more than just flow data.

By looking at other measured variables such as fluid speed of sound, temperature and pressure, the Katronic meters can be used as part of a product recognition system for pipes where the content of the pipe may vary during the pumping process.

For example, the KATflow 170 is being trialled by Petrobras in Brazil to detect changes in fluid type and condition on pipelines hundreds of kilometres in length.

Another sector where this technology can be employed is on tanker unloading systems where the customer needs to be able to determine between flows of seawater and crude oil in order to minimise wastage and ensure correct storage of the products flowmeters like the KATflow 100 and the KATflow 150 are already a cost-effective solution for pipes greater than 200mm in diameter and once the additional installation costs are taken into consideration then the meters can offer the customer significant cost savings.

Unlike clamp-on flow meters, when fitting an electromagnetic device, elements such as manpower, tools and lifting equipment, can add to the cost of installation.

Additionally, consumables such as seals and bolts and longer term considerations like recalibration mean that the cost of ownership of any inline device can quickly add-up to the point where a device such as a KATflow 150 is the cheapest solution.

To this end, the instrumentation frameworks for the UK water companies now require that bidders be able to offer clamp-on flow meters as part of their standard product offering.

Katronic KATflow 170 Ultrasonic Flowmeter

The future for the technology

All recent market forecasts would seem to indicate that the future is bright for the ultrasonic flow meter in general, and specifically the clamp-on devices, as part of a new generation of instrumentation finding maturity and acceptance.

As manufacturers find new uses for the technology supported by advances in electronic component production, clamp-on flow meters will be found on an ever widening range of applications.

Clamp-on gas devices are already going through the same development cycle that the liquid ultrasonic meters went through twenty years earlier.

As customer’s requirements drive companies to try alternative concepts, and legislation further opens the door for new instrumentation, an innovative breed of ultrasonic meters will be fully and fairly taking their place alongside and sometimes replacing traditional technologies.

Katronic Ultrasonic Flow Meters

Katronic Ultrasonic Flow Meters

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