Jornt Spit
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This time’s guest blogger is Dr Jornt Spit. He’s a researcher at the Radius research group at Thomas More University of Applied Sciences in Belgium, and has a background in biochemistry and biotechnology. The Radius researchers are working on renewable biomass, involving the cultivation of algae and insects that are then processed into valuable raw materials for a bio-based economy. As part of their research activities, they use Bronkhorst mass flow controllers to enable precision flow of carbon dioxide.

CO2: a valuable alternative carbon source

In recent years, carbon dioxide (CO2) has been steadily attracting attention as a valuable source of carbon. Of course, the rising concentration of CO2 in the atmosphere is a major and growing concern, and this is driving an increasing focus on sustainability in society. In line with this, we at Thomas More are working to achieve a more circular economy and a more bio-based economy. This means obtaining materials, chemicals and energy from renewable (energy) sources, and not from fossil fuels. Alternative biomass could become a major source in this approach.

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Currently, the main activity of our research group is cultivating renewable biomass, partly in the form of algae. We’re doing this under controlled conditions in the horizontal tubes of a photo-bioreactor. We use pure gaseous CO2 as the source of carbon. We’re cultivating algae with a view towards various applications. Algae can be very useful in the cattle feed sector, for instance, or in the food sector, the health products or ‘neutraceuticals’ sector or the cosmetics sector. Our research group is not heavily involved in further developing these applications – we’re focusing on optimising the cultivation of the algae, or in other words the process technology aspect.

Algae for conversion into valuable raw materials

Micro-algae form a really large and diverse group. More than 50,000 different species of algae have been identified and there are probably many more, running into hundreds of thousands. They are single-celled organisms, but can sometimes also form colonies. Algae are photoautotrophic organisms, which means that they use CO2 as a source of carbon and then convert this into sugars by means of photosynthesis. The micro-algae that we cultivate contain a particularly large amount of interesting substances: proteins, sugars and fats being the main groups. In addition, the micro-algae also make high-value chemicals such as pigments and antioxidants. To give one example, we at Radius cultivate a special alga that produces the valuable red colourant phycoerythrin. You can pretty much regard algae as tiny factories that can produce all kinds of substances that we need – so in order to synthesize these substances, we don’t need to completely reinvent the wheel. The various algae cells have evolved under evolutionary pressure to make these interesting substances, simply using a little sunlight, CO2 and a few nutrients. That means there’s a huge potential for utilising these substances.

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An algae culture increases in density through cell division. If conditions are right, then the algae will continue their cell division until a culture reaches its maximum density. At this point, the algae are harvested, so the algae biomass itself is the product. In our closed photobioreactors, we achieve a density of 1 to 2 grams of dry material per litre. When this point is reached, we take the algae out. This biomass can be directly used for food purposes or as cattle feed, but we can also further process the biomass, ‘break it open’ and extract the most interesting substances. If we take this latter approach, it’s called bio-refining or extraction. The whole process of cultivating, harvesting and further processing the algae presents a major challenge. That’s because each step is important and has to be carried out as efficiently as possible to ensure that the entire operation is profitable.

Mass flow controllers for precision flow of CO2

To optimise growth, it’s important to select an alga that grows well under the conditions we can provide in our unit. Not all algae species can absorb CO2 with the same efficiency, and not all algae grow equally fast. In our research, we find out which temperatures are best for growing the various species of algae, and how much light a particular alga needs. Here on the campus, we use natural sunlight: the photobioreactors are in a greenhouse. As a result, the algae grow during the day, when the sun shines, and not at night. One of the research questions we are investigating as part of the ‘EnOp’ Interreg project is: if we add extra CO2 to the reactor, how much faster will the algae grow, and which algae types absorb the CO2 most efficiently? In order to answer this question, we need mass flow controllers, because we want to know exactly how much CO2 we have added.

The CO2 is mixed with inflowing air that is channelled to the reactor, after which the CO2 dissolves in the liquid culture fluid, which also contains other nutrients. Since CO2 (carbon dioxide) is a weak acid, the pH level of the fluid steadily falls. This has a negative effect, because most algae grow best at a pH level between roughly 7 and 8. However, as the algae grow, they absorb CO2 from the fluid, making the pH rise again. The acidity level is a highly critical factor – if the pH moves outside the desired zone, then the algae tend to flocculate. The dosing system is therefore linked to the pH level, to optimise the supply of CO2 as precisely as possible. In this way, we can establish the maximum growing speed of the alga and how much CO2 we need to add to achieve this.

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If we add too much CO2, then the pH of the fluid will fall too strongly, and the algae won’t grow enough. If we don’t add enough CO2, that in itself isn’t a problem, but the algae will grow more slowly, because their growth is limited by lack of carbon dioxide. For each alga, an optimum amount of CO2 can be added. Moreover, the CO2 needs to be given time to dissolve in the fluid. If the CO2 doesn’t dissolve, then it will ultimately escape from the reactor again, which means you’re simply wasting CO2. Whether the CO2 is effectively dissolved and absorbed therefore needs to be taken into account as well. The design of the reactor plays an important role in managing this aspect.

As you might have noticed, precision is very important in this process. The mass flow controller ensures that we can keep the whole process stable around the right pH level and that we know exactly how much CO2 has been added.

…and the future?

If this process is scaled up to actual production scale, then logistics will become a major factor in determining where the CO2 comes from. In principle, it’s possible to use exhaust gases straight from factories, but then you need to remove substances like sulphur oxide and nitrogen oxide, which are also present in these flue gases. If the levels of these substances are too high, they will inhibit the growth of the algae. There are technical solutions to this problem, however. The next question is: how far away can the algae factory be from the CO2 source? If this distance is too great, then the CO2 will have to be transported in another, controlled form, such as bicarbonate. Another option is to develop CO2 air-capture units that enable local extra CO2 to be extracted from the air. The University of Twente is working on this technology in another Interreg algae growth project, known as IDEA and currently running in North West Europe. The Radius research group at Thomas More UAS is also involved in this project. In technological terms, we know it’s possible, but the crucial point is how much the technology will cost.

Links to:

• Read the complete application story ‘Controlled CO2 supply for algae growth’; • More information about Thomas More UAS; • More information about the ‘Enop’ project for energy storage using CO2 conversion technologies; • More information about the ‘IDEA’ project for implementation and development of economically viable algae-based value chains.

Jornt Spit was interviewed by Eddy Brinkman to produce this blog (Betase/Bronkhorst)

Dirk Jan Boudeling
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Today I would like to share an application story with you using mass flow meters in an application at Umicore in Suzhou (China). Umicore is one of the world’s leading producers of catalysts used in automotive emission systems. The company develops and manufactures high performing catalysts for, among other things, gasoline and diesel engines to transform pollutants into harmless gases, resulting in cleaner air.

Umicore’s production location in Suzhou ‘Umicore Technical Materials’ is using Bronkhorst Mass Flow Controllers and Vapour Systems for research and testing of automotive emission catalyst materials. Newly developed catalytically active materials of Umicore consist of oxides and precious metals, such as platinum and palladium, incorporated into a porous structure which allows intimate contact with the exhaust gas.

What catalyst materials does Umicore test?

Umicore in Suzhou uses various test benches in which newly developed catalytic materials are tested on performance (read: low output of toxic emissions). “Umicore develops new catalysts directly with top-tier automobile manufacturers in China. We are testing new formulations of materials and shapes of the catalysts on performance” explains Mr. Yang Jinliang.

Umicore project with Bronkhorst flow meters

How are the mass flow meters and controllers applied for identical testing and simulation?

The Bronkhorst mass flow meters and controllers are used to accurately deliver the right amount of several gases in a mixture that simulates the exhaust of an engine in different circumstances. “To really compare the performance of newly developed formulations, we have to be sure that the operational conditions of our tests are identical.” Mr. Yang explains that this requires the use of high performance mass flow controllers to accurately mix the simulated exhaust gas.

“We need flow control equipment which is reliable and has excellent repeatability during our simulation runs. Therefore Umicore developed the test equipment together with the Bronkhorst flow specialists.” Umicore runs various simulations. “We simulate exhaust gases of engines under various life cycle simulations and operating conditions. For example, the exhaust gas of the car is different if the engine is still cold or if the engine has a high number of revolutions.”

Test bench for ageing simulation

One special test bench of Umicore simulates the ageing of the catalyst materials. This has been achieved by heating the ambient temperature of the Catalyst up to 800° Celsius for a couple of hours up to 24 hours in a test run while adding the simulated exhaust gas. “Here the Bronkhorst instruments prove high stability under the harsh testing conditions,” says Mr. Yang.

Test bench for ageing simulation with flow meters

Exhaust gas simulation recipe

In order to simulate engine exhaust gas, Umicore mixes multiple gases. In general the following reactions take place in the catalytic converter:

1.Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2

2.Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2

3.Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2]O2 → xCO2 + (x+1)H2O.

To mix these gases, EL-FLOW Select digital mass flow controllers are being used. In order to maintain the gas mix under the same pressure, an EL-PRESS pressure controller instrument is used to control the pressure simultaneously with the flow.

Exhaust gases of engines also contain evaporated H2O. For this purpose the Bronkhorst ‘Controlled Evaporation Mixer’ (CEM) is used. All digital mass flow controllers, pressure controller and the CEM are connected with a computer that runs a software program to control the instruments.

In the ageing simulation test-bench of Umicore, high-temperature mass flow controllers of Bronkhorst are applied. The Bronkhorst EL-FLOW Select controllers have remote electronics to resist gas temperatures as high as 110° Celsius and still control the gases with high accuracy and excellentrepeatability.

Mr Yang Umicore

How do you like the support of Bronkhorst products in China?

When asked about Bronkhorst support and service in China, Mr. Yang is very enthusiastic: “All Bronkhorst experts in China are very professional and have quick response. Especially during the start-up phase of our project, when we needed it most, my contacts were determined to support us. The system runs smoothly, but it’s comfortable to know that Bronkhorst is having one of its Global Service Offices in Shanghai if we need calibration or service.”

Bronkhorst Global Sales Office

• Learn more about another application in this market: Simulation of exhaust gas to test lambda probes. • Do you want to stay up-to-date with our new applications? Subscribe for our newsletter

Gerhard Bauhuis
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The temperatures are sky high! All winter you've thought about going camping, travelling with your caravan and planning precious family trips. Finally now it’s the time to leave everything behind, and for a moment, forget the busy daily live and struggling at home. However, everywhere you go, Bronkhorst is travelling with you. Bronkhorst plays a role in many more applications than you think, also when you go camping. Let me guide you through some mainstream products you often see at a camping site, and the involvement of mass flow controllers.

Surface treatment

If you are travelling to your holiday destination by car, you will constantly look at some Bronkhorst solutions. Let’s start with the dashboard of your car. Many cars have a leather dashboard; at least, it looks like leather. A major company manufactures ‘skin’ that covers a car's dashboard, to give it this ‘leather look’. The skin is produced by spraying liquid, coloured polyurethane into a nickel mould. A Coriolis mass flow controller combined with a valve forms the basis of this solution to accurately supply external release agent to the nickel mould surface.

Coating of a dashboard But also the foam within the dashboard is manufactured by using Bronkhorst products. To create foam, a gas is added to a mixture, containing acrylonitrile-butadiene-styrene (ABS) or polyvinyl chloride (PVC), to give it the right volume. Too much gas will make the foam unstable, too little and you’ll get a heavy solid block. Therefore, it is utterly important that the correct amount of gas is added with an accurate gas flow controller.

Glass coating

If you look beyond your dashboard, you’ll look through the front window of your car. To control the light transmittance of glass, but also to make glass water repellent, protect it from mechanical and chemical stress, increase the scratch resistance and shatter protection, thermal mass flow controllers are used for the coating process. By controlling individually process gas flows, film thickness uniformity improvements are achieved.

Coating on headlights

When polycarbonate was introduced as a replacement for headlights glass in the early 1980s, new problems arised. Headlights are subject to a harsh environment. Due to the position in the front of a car, critical parameters for lifetime and performance are weather ability, scratches and abrasion. To protect headlights from these factors, scratch and abrasion coatings have been developed that are sprayed on the headlights with the help of robots in which Coriolis mass flow controllers control the flow to the spraying nozzles.

Hydrophobic coating

However, surface treatment is not only applicable for glass and dashboards. If you have experience with camping, you will be familiar with how fierce the summer weather sometimes can be. The awning of your caravan needs to be water repellent - this also applies to your raincoat - to sustain the heavy rainfall now and then. To make fabrics and textiles hydrophobic, Empa - a research institute of the ETH Domain, applies plasma polymerisation to deposit thin, nanoscale layers on top of fabrics and fibers. For this, they are using a Controlled Evaporation and Mixing system, in short a CEM system. In one of our previous blogs ‘Hydrophobic coating, the answer to exercising in the rain’ you can read about this application.

Image description Mass flow controllers are used to make awnings hydrophobic

Odoration

Bronkhorst is also involved with many smaller attributes you will encounter on a campingsite. Most people still enjoy the comfort of gas for heating or cooking on the stove. But also with gas we are able to fire up the barbecue in no time at all, in comparison with the old-fashioned briquettes that are sometimes hard to ignite. When gas escapes from a pressurized cylinder, you’ll recognize this from its penetrating scent. However, like Sandra Wassink stated in her blog “How mass flow controllers make our gas smell”, natural gas is odorless. By controlled supply of odorants like Tetrahydrothiophene (THT) or Mecaptan with a mass flow controller, the scent is added to the natural gas on purpose.

Barbecue

Let’s stay with the topic scent for a moment. For when we want to decrease the amount of mosquitos in our surroundings, we often enlight a citronella candle when we are getting tired of using the flyswatter. With the CORI-FILL dosing technology, Bronkhorst offers an easy-to-use setup to dose fragrances, like citronella, in candles. The addition of fragrance to a candle should be carefully monitored to ensure the candle burns cleanly and safely. To read in more detail about the production of scented candles, please read the blog of Graham Todd.

LED lighting

However a candle can bring much light to your surroundings, you won’t take a candle with you when you haste to the camping toilets at night. Instead you will use a flashlight of course. The working principle of the LED (Light Emitting Diode) inside this flashlight is a technology where Bronkhorst plays its part. LED works via the phenomenon called electroluminescence, which is the emission of light from a semiconductor (diode) under the influence of an electric field. By applying a semiconducting material like Gallium arsenide phosphide for instance, the manufacturing of red, orange and yellow light emitting diodes is possible.

Flashlight

I already told you so much, but frankly, just a tiny bit of all the camping applications we are involved at. Hopefully you got some more insights on the importance of Bronkhorst in many industries, also when you go camping.

If you want more information concerning the discussed applications, please contact us.

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Marlies
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The automotive industry is the biggest industry in the world. Some quick facts: • Approximately 99 million motor vehicles are produced per year (source: European Automobile Manufacturers Association). • The world’s largest car-producing countries are China, Japan, Germany, India and South Korea (2017). • There is a large discrepancy in the average annual distance travelled by car between countries. In the US, this figure is around 21,500 km/year. In Europe, the average is 12,000 km/year (source: Odyssee). • On average, a car has 30,000 parts (source: Netstar). A lot of people go to their work and on holiday by car. I do as well. I use my car every day, but while driving to Ruurlo, I had never realised that the flow meters which we develop have been used to produce my car. Did you? Inspired by that realisation, I discovered that our flow meters play a role in a lot of applications in the automotive industry; probably not in all 30,000 parts, but for sure in some of them. I have therefore collected three interesting applications of flow meters in the automotive industry to share with you.

1. Accurate dosing of release agent

In its automotive department, a major company manufactures ‘skin’ that covers a car's dashboard to give it a ‘leather look’. This skin is produced by spraying liquid, coloured polyurethane into a nickel mould. To allow easy skin release from the mould without any damage, an external release agent has to be applied onto the mould surface prior to spraying the polyurethane. Bronkhorst was requested to supply a [suitable mass flow controller](http://www.bronkhorst.com/int/markets/miscellaneous-applications/application-note-a075-gp03-accurate-dosing-of-release-agent/ ) in order to dose this release agent.

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2. Valve seat testing

Valve manufacturers check any metal-to-metal valve seats using pressure degradation methods. Since the new generation of car engines are running on higher pressures, the manufacturers are in need of new methods for leak testing to keep up with customer needs. Recently, Bronkhorst has been successfully involved with manufacturers of [valves and valve seat testing machines](http://www.bronkhorst.com/int/markets/miscellaneous-applications/application-note-a056-gp03-valve-seat-testing/ ) to implement low-flow measurement as an alternative method for a better performance.

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3. Simulation of exhaust gas to test lambda probe

Each modern car with a combustion engine has a self-controlling way to optimise engine performance. A lambda probe, a sensor positioned in the exhaust section of the car, measures the oxygen content of the car exhaust gases. This oxygen content, the ‘lambda value’, is a measure for the effectiveness of the combustion process in a car’s engine. The research department of a car producer needs to test the performance of these lambda probes with several exhaust gas compositions. To this end, they built an artificial exhaust line in which they do not use real exhaust gas but simulate the composition of car exhaust gases. They asked Bronkhorst to deliver [mass flow controllers](http://www.bronkhorst.com/int/markets/miscellaneous-applications/application-note-a069-gp03-simulation-of-exhaust-gas-to-test-lambda-probe/ ) for this purpose.

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Renewable energy in the automotive industry

Next to these applications at car manufacturers (or suppliers to the automotive industry), Bronkhorst instruments are also used by universities that join competitions or are doing research into renewable fuel sources for the automotive industry. For example, Green Team Twente is trying to build the most efficient hydrogen car. In this blog, they tell more about their research.

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In addition, Solar Team Twente participates in the World Solar Challenge every two years. Participating teams are challenged to design a car that drives 3,000 kilometers from North to South Australia in a maximum of six days, purely on solar energy. Bronkhorst sponsors this team. Read more in our news article.

A third renewable energy source being researched is formic acid (Hydrozine). In her blog, Lotte Pleging of Team FAST explains why they believe in formic acid (HCOOH) as a suitable candidate to replace fossil fuels and what the role of the Bronkhorst thermal mass flow meters is in the process of generating this renewable fuel. Read more below.

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Sources used:

http://www.odyssee-mure.eu/publications/efficiency-by-sector/transport/distance-travelled-by-car.html https://ceoworld.biz/2018/11/20/worlds-top-20-largest-passenger-car-producing-countries-in-2017-million-units/

Nicolaus Dirscherl
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Fish consumption is rising. With the increase of the world population and the need for nutritious food, health-conscious consumers are looking for alternatives to “a nice slice of meat”. And they end up eating more fish or vegetarian food.

Specific species of wild fish are getting more and more scarce in open water due to the huge impact of industrialised fishing fleets and overfishing. The sea can not provide the increasing demand. Fortunately, in a trend towards sustainable food production, fish farming is gaining increasingly interest.

Fish farming

Fish farming is the aquatic peer of farming cows, sheep or chicken. For many, many years, we as humans have been farming our main food - have it grown in greenhouses, in stables, or in the fields. Whatever we need, we try to fulfil our demand - more and more in a sustainable way, with respect for natural resources. Fish farming is heading in the same trend.

When people hear about fish farms, they might think of an aquarium, a little pond or a floating net. But in Norway, a major player in fish farming, people think on a larger scale. A typical fish cage near the Norwegian coast has a diameter of tens of meters containing 200,000 to 300,000 salmon. In the near future, these designs will upscale to 1 or 2 million salmon. Only in Norway, at the beginning of 2018 more than 3500 cages for fish farming were floating in the sea. And ‘Norway’ is expanding their knowledge and technology across the world, where people are interested in large scale harvesting of fish in the sea - or maybe also on land.

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Salmon is a typical example of a fish that can be fish farmed. They need cold water - seven to nine degrees Celsius is what they like most - which is why this aquaculture is happening in the northern hemisphere, off-shore in the fjords. Moreover: salmon is a very popular fish, often found on the menu all around the world - so there is a high demand.

Aeration

In fish farming, aeration is literally of vital importance. In addition to food, the fish need oxygen that is supplied in the form of tiny air bubbles (‘aerated’) to the water. But aeration has more advantages.

Also in the early days, lice were a major disease that salmon suffered from. Since salmon lice had an impact on harvest, the fish farmers had to look for solutions. For some reason - maybe it was an experiment or it happened by accident - they started to purge air from the bottom of the cage. And they observed that the movement of the fish started to change. Instead of circling day in and day out - as salmon normally do - they started to move around the cage and became more agile. If the salmon are more agile, the muscles have to work more, and meat from moving animals has a better quality. At the same time, the fish farmers detected that aeration helped them to create a more thermal friendly water environment, with an advantageous temperature, conditions and amount of oxygen. With result that the occurrence of salmon lice reduced. So aeration had - and still has - two advantages: improving the salmon quality, and reducing the unwanted lice. By the way: the words purging and aeration have the same meaning. ‘Aeration’ has the word air inside.

Aeration of fish farms using mass flow controllers

The process of aeration is very simple - like in any aquarium you have at home - and yet can lead to very nice results as we saw above. The air bubbles can be generated by natural water currents (off-shore, down-hill), pumps, impellers, variable area flow meters or - as we do at Bronkhorst - by mass flow controllers and compressors. Here, a compressor generates compressed air from the surrounding atmosphere, and feeds this to the mass flow controller for controlled aeration of the water in the fish cages.

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To run fish farms remotely controlled and without much manpower, as much automation as possible is required. This also involves automated feeding. When the fish are fed, the air purging needs to be interrupted to give the fish the opportunity to hunt for the food before it floats out of the cage. In between the feeding periods, the aeration improves the condition of the water and the salmon. Here, it helps that mass flow controllers are remotely controlled from the control room at land. The aeration is stopped when the feeding starts, and when the feeding is over, the previous set point will automatically return and the water condition is as stable as it was before.

But there is more: mass flow controllers provide a potential for saving energy due to better conditions in the cage. The accuracy of the devices is important here. Every cubic meter of air you save by being more accurate - faster control or opening of valves - is of direct influence to your costs for running the compressor. Moreover, in stormy weather you can reduce the aeration, but during a long dry period without water movement, more air bubbles are needed. So essentially, this accuracy and flexibility leads to a better controlled environment.

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With MASS-STREAM mass flow controllers we have a robust instrument, which is performing well in the harsh northern surroundings. By Bronkhorst standards, this kind of aeration is a ‘high flow’. Typical air flows for a fish cage are in the range between 600 and 1400 liters per minute.

Mass flow controllers for other types of aeration

Mass flow controllers are suitable for other types of aeration - also again in aquaculture and agriculture. If you grow salmon, you need to breed the fish, which normally occurs on land. Fish eggs and young fish are even more vulnerable to changes, so the environment has to be more stable than for grown fish. Depending on the type of fish, the balance of oxygen in the water is delicate and has to be controlled accurately.

In algae farming, carbon dioxide gas is one of the food components for these species to grow, which needs to be supplied under defined conditions.

A very well-known application of aeration is in food & beverage industry. As you might know, every soda or carbonised drink is a liquid purged with carbon dioxide gas. Related to that: when packaging food, the packaging is purged with nitrogen to remove the oxygen before the food enters the packaging, as one of the steps to prolong the shelf life of the food.

“Fish farming with controlled aeration by mass flow controllers will support the focus on good fish quality, control of diseases and increase of the yield” according to Nicolaus Dirscherl, Managing Director of M+W Instruments GmbH.

For more information about the usage of mass flown controller in a fish farming application, please check our application story Aeration in Fish Farming.

Check out the products used in this application.

Ferdinand Luimes
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A Coriolis mass flow meter is known as a very accurate instrument and it has many benefits compared to other measuring devices. However, every measuring principle has its challenges, as also the Coriolis principle. It can be a real challenge using Coriolis instruments in low flow applications in the heavy industry where you may have to deal with all kinds of vibrations. In this blog I would like to share my experiences with you regarding this topic.

The Coriolis principle

Coriolis mass flow meters offer many benefits above other measuring devices. First of all Coriolis flow instruments measure direct mass flow. This is an important feature for the industry as it eliminates inaccuracies caused by the physical properties of the fluid. Besides this benefit, Coriolis instruments are very accurate, have a high repeatability, have no moving mechanical parts and have a high dynamic range, etc.

Read more about the importance of mass flow measurement and the relevance of Coriolis technology in a previous blog.

Do vibrations influence the measuring accuracy of a Coriolis mass flow meter?

In industrial applications, all kinds of vibrations with different amplitudes are very common. A Coriolis meter measures a mass flow using a vibrating sensor tube, which fluctuation gets intentionally out of phase when the fluid flows through. As explained in the video [link] at the end of this article.

This measurement technique is somewhat sensitive to unwanted vibrations with a frequency close to the resonance frequency of the sensor tube (this depends on the sensor tube design, e.g. 360 Hz) or a higher harmonic of this frequency (see picture below).

resonance

The likelihood of the occurrence of these unwanted vibrations is higher in an industrial environment. Coriolis flow meter manufacturers do their utmost to reduce the influence of vibrations on the measured value by use of common technical solutions, such as using:

  • higher driving frequencies
  • dual sensor tubes
  • different sensor shapes
  • mass intertia (e.g. mass blocks)
  • passive and active vibration compensation
  • pigtails

So yes, vibrations can influence the measuring accuracy of your Coriolis flow meter, but only if the vibrations have a frequency close to the resonance frequency. What can you do about this? This depends on the kind of vibration.

What kinds of vibrations do exist?

In an industry zone frequencies can be generated by:

  • environmentally related vibration sources (such as: truck, rail transportation, industry activities)
  • building-based vibration sources (mechanical and electrical installations, like air conditioning) or
  • usage-based vibration sources (installed equipment and machines, e.g. pumps, conveyor belts).

These vibrations travel through a medium like the floor, in the air, through pipes or the fluid itself. If these vibrations disturb the Coriolis frequency, the measured flow could be incorrect in some extent.

To minimise the effects of vibration it is useful to identify these sources. Sometimes, it is possible to move the flow meter just a little bit, turn it (Coriolis flow meters are in most cases less sensitive to vibrations if the meter is rotated 90 degrees), make use of a big(ger) mass block, use flexible tubes or U-bend metal tubes or use suspension alternatives.

How could you check the performance of a Coriolis flow meter?

A well performing flow meter and controller will give the best process result. Therefore, it is advisable to test a Coriolis flow meter in your application if you expect heavy industrial vibrations before you trust it to the full extent. Be careful when filtering the measuring signal. In some cases it makes sense (e.g. when a quick response isn’t required), but if you want to test the performance of a flow meter, filtering could blur your judgement.

Coriolis dosing block

If in specific circumstances the Coriolis flow meter isn’t performing the way it should, the operator will see a shift in the process output – for example in an application dosing colour to a detergent it can result in differences in product colour by incorrect dosing and/or unexpected measuring signal behaviour. In these cases it makes sense to check the raw measuring signal (without filters!), because it will give you a good insight in the performance of the flow meter. Ask your flow meter manufacturer how to switch off all signal filtering.

Standards regarding vibrations

Remarkably, the influence of external vibrations is not clearly defined in a standard for Coriolis flow meters. Several standards are written about vibrations, but none in respect to measuring accuracy in relation to vibrations. However, two useful standards in relation to vibration are:

  • IEC60068-2, Environmental testing for electronic equipment regarding safety
  • MIL STD 810, Environmental engineering considerations regarding shock, transport and use

As a user of Coriolis flow meters it is important to understand your application, especially about potential external vibration sources. As low flow Coriolis specialist we work together with knowledge partners like the University of Twente and TNO (a Dutch organization for applied scientific research) to get a continuous improved understanding of this topic.

With in-house test facilities we are able to do special vibration tests. Together with the experience we gained from customer applications and custom made solutions, we are always aiming for improving our Coriolis flow meters to give our customers the best performance they need.

Watch our video explaining the Coriolis principle

Learn more about the Coriolis measuring principle

Read more about the importance of mass flow measurement and the relevance of Coriolis technology in a previous blog.

Check out our success story using Coriolis mass flow controllers for odorisation of our natural gas.