Confusion over radar level measurement

We have learned not to get too confused over suppliers using buzz-words and clever marketing names, but recently it seems the major level measurement system vendors have been introducing new and higher radar frequency systems as their latest development – and therefore, by implication, maybe the best. We were used to 6 GHz, and then 26 GHz radar frequencies, but why should we suddenly go to 80 GHz? Then, perhaps just to add a little excitement to the mix, Endress+Hauser started talking about 113 GHz!

113GHz_Key_Visual

The E+H radar line up that offers 113GHz!

This article was first featured in the journal South African Instrumentation & Control in September 2017, a journal published by Technews

Let’s dispel a few myths. Firstly, in the same way that lasers for fibre-optic communications systems made the technology available to create infrared optical systems for process gas analysers, and mobile phone technology possibly provided the hardware for the first radar level measurement systems; the 80 GHz versions are a result of measurement technology made commercially viable on the back of production investment in the distance measurement systems and parking sensors used in modern cars. So the suppliers take the available sensors and chipsets to create a new industrial product, and then have to find the best applications – in this case, the ones that might benefit from the 80 GHz.

Secondly, E+H do not have a 113 GHz system, this is a marketing statement, made to catch attention – ‘with a wink’ is their expression. They claim a ‘complete radar competence of 113 GHz’ because this is the sum of the many different frequencies their different sensors use! These are 1, 6, 26 and 80 GHz.

So why have different frequencies?

Possibly the best explanation for the applications suited to the different frequencies has been provided by the Rosemount measurement division of Emerson, in their “Engineer’s Guides”. The Emerson expertise stretches back many years, having acquired the Saab Tank Radar business. Per Skogberg, from the Gothenburg HQ in Sweden, separates the devices into low, medium and high frequency, to generalise.

Radar signals are attenuated, i.e. they lose signal strength as they pass through the air, or vapour, above the liquid. High frequencies are more severely affected than lower. When the air has moisture, steam or liquid droplets (from spray or filling) present, the attenuation is higher. Equally in solids applications, dust particles have the same effect. So low and medium frequency radar are best when there is dust or moisture present.

At lower frequencies, the wavelength is longer (30-50 mm), so surface ripples in a tank have a small effect. At higher frequencies, surface ripples and foam on the surface can be a problem. But the shorter wavelength of the high frequency units (4 mm) allows accurate operation over short ranges, for example in small tanks. The higher frequency units can use a smaller sensor construction, so the unit is easier to install. The beam angle is narrower, so it can be aimed at a smaller target area and therefore can be positioned more easily to avoid any obstructions in the tank. But even this can be a disadvantage, as the installation needs to be exactly vertical and any turbulence of the surface during filling or stirring can cause the signal to be lost temporarily, in larger tanks.

When reading these suggestions, it is important to remember that Emerson does not offer an 80 GHz unit yet, so their marketing approach would naturally bias users to look at low and medium frequency units. The suppliers of high frequency units (Vega, Krohne and E+H) would point out that in many liquid storage tanks the surface is undisturbed, since any foam, turbulence and significant ripples (>2 mm) caused by filling or liquid transfer will only cause short-term interference. Plus the small antenna size and short range performance make 80 GHz units very useful for smaller process vessels and tanks.

Radar system types

There are two types of radar systems, Guided Wave Radar (GWR) and Free Space Radar. The GWR systems use a conducting rod, or similar, extending down into the liquid, often working in a stilling chamber attached to the main process tank. These operate at low microwave frequencies, and are independent of surface turbulence and foam. They are useful for shorter range measurements and interface measurement between liquids, as well as long ranges.

The Free Space Radar systems are more widely used, since they are top-mounted with nothing in the tank: indeed, some can operate through non-conducting windows in the tank roof. Low and medium frequency radar systems generally transmit a signal pulse and measure the liquid distance by the time delay for the returned pulse. High frequency (80 GHz) systems use an FMCW radar measurement, where the frequency of the transmission is swept, and the frequency difference of the returned signal is measured to assess the distance. The FMCW technique is also used at 26 GHz in some recently launched sensors.

Radar systems can transmit their measurement data using 4-20 mA, fieldbus systems like HART, FF, Profibus PA and Modbus, or indeed via wireless systems like Bluetooth. The low and medium frequency pulsed radar systems generally operate over a two-wire interface: some of the higher frequency FMCW systems require more power and use a separate power connection.

Major applications

Simple low-cost radar level measurement sensors have been specifically designed for water industry use, in sewage sumps and flume flow measurement, by Vega and Endress+Hauser. Vega suggest that 40,000 such sensors are now in use in the water industry, mainly in Europe, and claim their total output of such sensors exceeds 550,000 units over the last 25 years.

Several of these devices use simple Bluetooth interrogation and programming from a handheld PDA: E+H demonstrates this at its facility in Maulberg, working on the stream that runs through the factory complex, as seen below.

Micropilot_FMR10_FMR20_on test stream at Maulberg, with operator using Bluetooth

Both E+H and Vega produce further industrial units for use on process vessels, and storage vessels for solids and liquids. Recently, E+H has extended its capability to add long-range units, such as the 80 GHz FMR62, working at up to 80 m range, with an accuracy of 1 mm. Other units work up to 125 m range, at 3 mm accuracy. These units will eventually be aimed at the large petrochemical industry storage tank markets, and specifically are working towards use for custody transfer duties.

Krohne have similarly announced a new range of its 80 GHz Optiwave sensors. Some of these can even operate at up to 700°C, for example for use on molten salt vessels in solar power plants. Lower specification units rated at up to 150°C can be used through a tank roof made of plastic, or similar materials. Suitable for small or narrow tanks, the unit can measure ranges of up to 100 m. Krohne also offers lower frequency Optiwave systems for use on solids and powders, or to electronically monitor the float position in magnetic level indicator columns attached to process vessels.

Postscript: Krohne is organising a webinar with the title “80 GHz Radar Level – Allrounder or Overrated?” to discuss their recent developments with such systems. This webinar will take place on 18th October 2017 at 3pm London time/10am New York time.

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Protect your flowmeter IP

trevor-forsterThe following comments come from Trevor Forster, the MD of Titan Enterprises, a specialist flowmeter manufacturer based in Dorset, UK. He recounts his experiences over the development of a new style of time-of-flight ultrasonic flowmeter, later called the Atrato, in their latest newsletter, called the Titan Flowdown. It is an interesting experience and maybe holds some lessons for all.

“A few years ago, Titan Enterprises filed a patent application for some new ultrasound technology we had been developing over the previous 12 months. On examination by the patent authority it transpired that someone else had the exact same idea and had filed some three months before us. Annoyingly this competitive filing was nine months after we had our first thoughts and six months after our first successful experiments. There were two valuable lessons here:

  1. File your ideas as soon as possible.
  2. Do not waste time in developing a completely viable idea before protecting the intellectual property behind the innovation.

As a consequence of this setback we had to revisit what we wished to achieve with our ring technology development. This project involved development of an ultrasonic device which was tolerant to variations in tube diameters due to the material, temperature or pressure. Our new idea was to section the device annulus into several segments which where independently acoustically coupled to the pipe but joined electronically. The benefit of this innovation is that it would provide us with a “flexible” crystal which can accommodate variations in the tube diameter as well as having a consistent acoustic connection.

Our developmental options were to make drawings, get the specially shaped crystals manufactured and then perform the tests. Alternatively we chose to get some miniature diamond cutting saws with appropriate boring burrs and make our own segmented crystals from existing larger crystals which we use on another ultrasonic meter. This enabled us to prototype and test our idea much more quickly.

The initial tests on the new device were extremely promising which gave us sufficient confidence to file our patent application while more accurate components were being manufactured and tested. This technology has formed the basis of our soon to be released Metraflow ultra-pure flowmeter and our developments with a new 1350 bar flow device.

The initial disappointment was a valuable lesson in getting intellectual property registered as quickly as possible especially with any rapidly developing technology.”

ENDS

Editor’s comment:

From previous discussions about this development, the initial research and testing of the flowmeter concept was undertaken in co-operation with a University, using a research student, so the development was not completely ‘under wraps’, under the control of the company. Nevertheless in a fast developing technology area, many minds are grappling with similar perceived problems and solutions, so parallel work would have been going on elsewhere: an early patent filing is very important under such conditions! The ultra-pure nature of the Metraflow flowmeter arises as the flow tube is a simple straight glass or similar tube, and the ultrasonic transducers are all external. To register to receive further info on the Metraflow, please email Titan.

600,000 flowmeters measure beer and lager flow

Titan Enterprises has established a long-standing working relationship with Vianet plc (formerly Brulines) for the supply of beer flowmeters for pub and bar automation projects. Over the last 20 year period Titan have delivered, and Vianet has installed, over 600,000 of these meters for beer and other bar flow measurement and automation applications.

Brulines, was formed in 1993 with the intention of providing pub chain owners with data on their bar activity via an electronic point of sale (EPOS) system. After trialling several other flowmeters, the company sought a solution to resolve flowmeter bearing lifespan problems and to overcome the unreliability of the optical detection method in beer.

beer-meter

The beer flowmeter

Following a collaborative approach to developing the solutions needed for the Vianet customer base, Titan Enterprises proposed an adapted version of its 800-series turbine flowmeter as the design included durable sapphire bearings proven reliable for many thousand hours operation, and a Hall effect detector which was not subject to problems with discolouration inside the pipe. After successful tests, a trial order for 400 units was placed in 1997, which after the subsequent field trials, was followed by an order for >5000 meters which were all delivered to the clients required timescales.

To ensure the flowmeter was ‘fit for purpose’, Titan additionally adapted the cable type as well as the body and increased the length to 10 metres. These adaptions enabled Brulines installations to be maintained in beer cellars with differing wire runs to the control panel without any junction boxes.

Twenty Years of Collaboration

With the widespread reliability of this product, Vianet turned again to Titan Enterprises in 1999 to develop for them an “intelligent” flowmeter (IFM) for their enhanced iDraught retail product. The specification for the IFM required that it should additionally measure temperature as well as determining the type of fluid in the line to detect line cleaning cycles which are essential for the dispensing of a good pint.

At the time, Titan did not have the technology to provide sensing electronics at a reasonable price so we produced a revised version of the beer flowmeter with the capability of being matched to a PCB designed, manufactured and installed by a third party.

After trialling and testing, this new IFM was introduced in June 2000 and supplied to Vianet at the rate of up to 3500 units a week. Mark Fewster, product manager at Vianet commented “Titan’s supply chain has always delivered to our quality and timescale needs”.

IoT Developments

ifm latest

An intelligent flowmeter design

Since this first IFM introduction, close collaboration between the two parties has resulted in 5 iterations of the product with revised features as end user requirements have developed and evolved with the growth of the IOT (Internet of Things). Drawing upon this close working relationship, over a long period of time, Titan continue to work with Vianet on new solutions and offerings as the Vianet customer offering further develops.

This Titan Enterprises application story is based on a report in the Autumn issue of Flowdown, the regular news bulletin published by Trevor Forster, MD of Titan, from their Dorset, UK base.

Yokogawa acquires FluidCom chemical injection valve technology

Yokogawa has announced the acquisition of TechInvent2 AS, a Norwegian enterprise
that holds the rights to FluidCom, a chemical injection metering valve (CIMV). The FluidCom CIMV prevents blockages and corrosion in oil wells, pipelines, and other facilities and employs a patented technology for thermal control. It incorporates the functions of a mass flowmeter, control valve, and valve controller and has very few moving parts. FluidCom systems have already been delivered to several international oil and gas majors. With TechInvent2 joining the Yokogawa Group, Yokogawa will now target delivery of this solution to the oil and gas upstream and midstream sectors, thereby helping to improve operational efficiency, reduce operational costs, and enhance health, safety and the environment (HSE).

Background Information

Based on its Transformation 2017 mid-term business plan, Yokogawa will continue to focus on the oil and gas industries, and will strive to strengthen its solutions targeting the upstream and midstream sectors, in addition to its forte downstream sector businesses.

Following its April 2016 acquisition of KBC Advanced Technologies, a provider of consulting services that are based on its own advanced oil and gas simulation technologies, the company has been striving to work with its customers to create
value through the provision of solutions that address every aspect of their business activities. At oil wells and pipelines, efforts to ensure a secure oil flow path (flow assurance) play an important role in maintaining production efficiency. The adherence of various chemical substances to the inside walls of a pipe can reduces its internal diameter and causes corrosion. To prevent the accumulation of substances and corrosion, certain chemicals must be injected in the pipes. Improving the efficiency of this process is a major challenge in the upstream and midstream sectors.

The FluidCom CIMV

FluidCom

Chemical injection valves have traditionally been manually operated in the upstream sector, although there are cases where chemical injection has been automated using an actuated solution. In the former case, the valves must be frequently opened, closed, and adjusted by plant personnel. This is costly as it necessitates the hiring of additional staff, and it is work that must be done under very harsh environmental conditions in the field.

It is also a well-known problem that inaccurate and unstable dosing of chemicals leads to additional operational costs and challenges with specific processes. To address and resolve such problems, there is an increasing demand for integrated automatic injection solutions that perform stably and offer a high level of precision in the dosing. The FluidCom CIMV has a unique design which is based on a patented technology, providing integrated flow control and metering using a unique combination of material and thermal effects.

FluidCom is a fully automated and reliable device with a simple design that performs autonomous valve control and continuous flow metering. The device is able to stably inject chemicals in the required small amounts. It has few moving parts and has proven to be an accurate, reliable solution for the control of chemical injection applications. No regular maintenance is required and remote control features are provided.

The device features a self-cleaning mechanism that reduces maintenance workload, and the automatic injection of chemicals in the correct amounts eliminates the need for manual interventions by plant operators and maintenance workers, thereby enabling personnel to lessen their exposure to harsh environmental conditions in the field.

Chemical injection valves have traditionally been operated as manual systems in the upstream sector under harsh conditions. The FluidCom can automate chemical injection operation and reduce times that plant operators and maintenance workers go to field and operate in harsh environments. So using FuidCom improves healthy and safety.

FluidCom is also a valuable solution for downstream operations, where corrosion prevention is always a pressing concern. An ISA100 Wireless version is planned. The ISA100 Wireless technology is based on the ISA100.11a standard. It includes ISA100.11a-2011 communications, an application layer with process control industry standard objects, device descriptions and capabilities, a gateway interface, infrared provisioning, and a backbone router.

Commenting on the acquisition of this company, Shigeyoshi Uehara, head of the Yokogawa IA Products and Service Business Headquarters, said: “FluidCom will improve flow assurance, which is a key concern of our customers in the oil and gas industry, and it will make a major contribution to their operations by helping them not only improve production efficiency and reduce operational costs, but also enhance HSE. The combination of FluidCom, KBC simulation technology, and Yokogawa field devices will allow us to expand the range of our upstream and midstream solutions and enable the delivery of value in new ways to our customers.”

About TechInvent2

TechInvent2 is a fully owned subsidiary of TechInvent AS, a Stavanger, Norway-based company founded in 2008. TechInvent is owned by the founder and CEO Alf Egil Stensen, the venture capital firm Statoil Technology Invest AS, Aarbakke Innovation AS, and Ipark AS. The company has been supplying its FluidCom chemical injection technology to major oil companies since 2016. Alf Egil Stensen will continue as CEO of the company now that it is part of Yokogawa.

The mystery of intelligent sensor diagnostics @ProcessingTalk #PAuto

The fashion, or trend, that has developed over the last few years for process and analytical instrumentation sensors is to use their on-board intelligence to monitor their own performance status. They achieve this by monitoring and tracking various diagnostic measurements – secondary parameters where consistent values are said to indicate the sensor is working as it should, and has not been subject to any changes since leaving the factory.

This approach is easily understood if you consider the possible effects of exposure of a sensor to excessive temperatures, which might soften the potting or glues holding a sensor to a ‘window’ – and it can be expected that this would be detectable. The addition of a diagnostic sensor, such as a temperature probe, within the sensor housing, could also be an option for checking the sensor condition, and alarming if the sensor exceeds a high or low set-point.

But how else do sensors check their own performance, and how relevant are these “checks”? This topic was discussed in the latest issue of the South African Journal of Instrumentation and Control, August 2017 issue: SAIC is a journal produced by technews.co.za.

Modern (intelligent?) sensors

So, over the past two years of attending and listening to presentations, and reading relevant articles describing the advantages of self-monitoring systems and sensor diagnostics, waiting for an engineer’s explanation as to how the clever monitoring system actually tells the factory instrument engineer anything, it is a bit of a disappointment to report that there seem to be no suppliers that actually make any significant disclosure. This applies across sensors ranging from ultrasonic and Coriolis flowmeters, electromagnetic flowmeters, level measurement systems using radar or ultrasonics, and level alarms. Obviously all the major suppliers are involved in such equipment, and compete with each other, but this secrecy seems a little extreme.

The problem is possibly that until a manufacturer can point to a failure that was detected – or anticipated – using their diagnostics, and decides to publish it, the user population has no idea what systems might actually work. But equally, by publishing a success for the diagnostics, the same manufacturer is saying that one of his sensors failed – and that is a very unusual event, these days. Plus also maybe not something they would wish to publicise.

The older approaches

The whole idea of diagnostics and sensor monitoring has been around for a long time. From personal experience with Bestobell Mobrey, in the 1980s, Mobrey launched an ultrasonic version of a float switch, the ‘Squitch’, which switched a two wire mains connection through a load circuit. When not alarmed it just sat there taking a small control current. For customer reassurance that it was operating in this quiescent state, there was a blinking red LED to show that the sensor was ‘armed’ and operating normally. Mobrey called that a heartbeat indicator, a term that is now used more widely.

For custody transfer flowmeters, the classic approach to validate confidence in the reading is to use two meters in series, and check that both give the same answer. This has progressed to having two separate ultrasonic flowmeters mounted in the same flowtube, on some installations.

For the more safety conscious plant there are often requirements for duplicated sensors for such duties as high level alarms, where two different technologies are used by the sensors – e.g. by mixing float, capacitance or ultrasonic level alarms.

The modern approach

It seems that the ultimate approach is to let the sensor supplier link into your plant automation and data system to interrogate the sensor, and he will verify the measurement and performance diagnostics on a regular basis. With many and varied sensors, this leads to a lot of external interrogation of your plant assets, and possible worries over losing control of your plant.

Overall, it begins to look as though it is becoming impossible for a discerning plant engineer to decide which supplier has the best performing diagnostic system to monitor the relevant sensor’s performance. Rather like opening the bonnet of a modern car, and deciding it would be best to take it to a garage!

At a recent lecture on this subject, held by the InstMC Wessex section in co-operation with Southampton University, a detailed discussion concluded that the sensor suppliers now have all the real expertise in-house and a normal plant engineer could not be expected to cover the depth of this technology for all the many sensors and other equipment within his control. In the end the decision as to ‘which supplier to use’ returns to your own previous experience, including the service and support that has been and is now on offer, and the suitability of the product for the money available for that sensor task.

Fashions in sensor technology

I confess it was 50 years ago when I started looking at new technology for sensors. Back then, colleagues and I updated the old WW2 mine detector, using really low frequency (i.e. 1 kHz) magnetic waves to discriminate between ferrous and non-ferrous items, and assess the size and range of the target by the signal phase measurement. Here the electronics used ‘modern’ operational amplifiers, on a ‘chip’.

The 1980s

Ten years on, in the ’80s, the technology coming into vogue was ultrasonics, replacing float systems to make liquid level switches, and then, still using analog electronics, the first Doppler ultrasonic flowmeter appeared. With the availability of digital microprocessor circuitry, timed pulses transmitted through the air down to the surface of a liquid led to non-contact liquid level measurement, and major success in the automation of sewage sump pumping systems. (The success lasted maybe 30 years, as when the mobile phone business created low cost microwave components, similar systems based on radar began to take over in this market.)

The next leap forwards in the mid-’80s was the time-of-flight ultrasonic flowmeter – actually achieved with discrete digital circuitry, which was faster than the available microprocessors. The technology was originally developed at Harwell, for measuring liquid sodium flows in nuclear reactors, but these flowmeters found major application in monitoring clean water flows, primarily in water distribution mains. Over the next 25 years the technique was picked up by commercial interests, and continually refined, introducing clamp-on sensor systems, and adapting the technique for gas flows as well. Even domestic gas meters were introduced using the same principle. Eventually the microprocessor speed became fast enough to achieve the flow measurement accuracy needed – using multiple sound paths – for the fiscal measurement of oil flows, which is now one of the major applications, along with similar gas flow measurement tasks.

Other sensors where I was not initially involved were in the fields of gas detection – where for flammable gases, Pellistors created a major business area – and fire detectors. It seems that UV and IR fire detection systems are still seeking the best approach. Possibly because of the awareness brought about by the Internet, the pace of change and the commercial opportunities, the large corporations are quick to acquire small spin-off companies from university or other research after any small success, because of what technology they may have discovered: they do this ‘just in case’, to protect their market position.

Current developments

The area I see as most important currently, and a fruitful area to flag up for research projects, is in any style of optical analytical measurement sensor. Specifically, the component that brought this into industrial instrumentation was the tuneable diode laser (TDL), developed prior to 2005 for the telecommunications industry, to transmit telephone conversations and data down fibre-optic cables. Around 2007 Yokogawa acquired a business from Dow Chemicals, which used TDL sensors for near-infrared absorption (NIR) measurements of a gas mixture, which gave the proportions of oxygen, carbon dioxide and monoxide, and water vapour. This allowed the unit to be used as a combustion analyser for industrial furnaces, boilers etc.

Over the last 10 years this area of technology has grown in importance, and in its capabilities. Spin-off companies have emerged from various universities, like Manchester and Glasgow. A significant task in these developments is the application of the solution to an industrial problem: it needs the two factors of solving both the technical design and the industrial application. Cascade Technologies was established in Glasgow in 2003, and their analysers were initially targeted at marine flue gas emissions monitoring. From 2013 they added a focus on pharmaceutical gaseous leak detection, and also the process industry, on ethylene plants. Their technology allows multiple gases to be measured simultaneously. The Cascade business has now been acquired by Emerson.

Another closely market-focused supplier of NIR analytical systems is TopNIR Systems of Aix en Provence, in France, actually a spin-off business from within BP. TopNIR use their systems to analyse hydrocarbons – both crude oil and processed products – to allow a refinery operator to know how to most profitably blend the available components into a final product, as well as to minimise any quality give-away in blending the different grades of gasoline and diesel. TopNIR quote the annual benefit to a typical refinery at $2 to $6 million, with an implied investment spend of up to $2 million!

This article was first published in the May 2017 issue of “South African Instrumentation and Control” published by Technews.co.za

©Processingtalk.info

Battery Energy Storage Systems help UK power efficiency

Nidec ASI, of Milan in Italy, part of the appliance, commercial and industrial motor business of Nidec in Japan, has won an order from the UK-based EDF Energy Renewables business for the installation and supply of a second Battery Energy Storage System (BESS), for use on the British National Grid.

EDF ER, a renewable energy developer, is a JV company between EDF Energy in the UK and EDF Energies Nouvelles in France. As a result of this new contract, Nidec ASI will act as an EPC (engineering, procurement, and construction) contractor to supply the 49 MW BESS system that EDF ER is building to serve the National Grid, the British electricity distribution company. The contract, which follows closely after an earlier large-scale deal for a 10 MW battery energy storage system (also for National Grid) makes Nidec ASI reach a 33% market share in the British BESS systems market.

As renewable energy resources are more widely used – to reduce the environmental impact of power generation – investments in battery energy storage systems are becoming increasingly prominent. These stabilise the power grid by temporarily storing any surplus electricity generation, and discharging the saved electricity during power shortages. Last November Nidec ASI delivered the world’s largest (90 MW) BESS system to major electricity firm STEAG of Germany. As a leader in the BESS market, Nidec is committed to stabilizing the world’s power grids and contributing to realizing a low-carbon society via the spread and expansion of battery energy storage systems and high-quality state-of-the-art equipment.

EDF West Burton 2

The BESS will be installed at the EDF Energy West Burton site in Nottinghamshire, pictured above, to support the UK’s National grid.