2020 is a few days old and the plans and goals of this new year are starting to take shape. Let’s look back on last year. What did we achieve? Which blog post was the most fun, useful, gripping or interesting to you? Oh and by the way, we’ll assure you that we’re going to share all our knowledge about low flow, mass flow and flow meters even more often this year. From the overview of the 2019 statistics, we’ve come up with a top 5 of most popular blog posts.
- How to deal with vibrations using Coriolis mass flow meters
- Do you know why Mass Flow reference conditions matter?
- Real-time pressure and temperature compensation to optimize flow control
- Flow Meter Accuracy & Repeatability
- Flow control valves; the most used accessory in flow control
Top 5 most popular blog posts in 2019
1. How to deal with vibrations using Coriolis mass flow meters
A Coriolis mass flow meter is known as a very accurate instrument and it has many benefits. To be quite frank we were quite surprised that this blog post came in first place. In industrial applications, all kinds of vibrations with different amplitudes are very common. However, the question is whether these vibrations influence the measuring accuracy of a Coriolis mass flow meter. Ferdinand Luimes, Liquid Flow Technologies product manager, shares the advantages as well as the disadvantages of these flow meters and provides some handy hints in using these instruments.
2. Do you know why Mass Flow reference conditions matter?
The world of flow measurement applies reference conditions, which can be further divided into standard reference and normal reference. Another distinction is between European and American style. Chris King, Bronkhorst USA General Manager, sheds light on this apparently complicated construction in his blog post, detailing exactly what the differences are and explaining why these reference conditions matter.
3. Real-time pressure and temperature compensation to optimize flow control
This blog post topped the charts in 2018 and is still in the top 5 today, once again proving the relevance of this topic. As it turns out, various external factors can have an influence on the measurement accuracy and control stability of mass flow controllers. Vincent Hengeveld, Gas Flow product manager, explains the theory behind real-time pressure and temperature compensation.
4. Flow Meter Accuracy & Repeatability
Choosing which flow meter is right for your application is a pivotal element in its success. Generally speaking, the two important statistics are flow meter accuracy and repeatability. In his blog post, Chris King explains what these two parameters mean and why they are crucially important.
5. Flow control valves; the most used accessory in flow control
Finishing the list is a blog post about control valves, perhaps the most often used accessory in flow meters. A control valve is used to control a flow by varying the size of the flow passage. Do you know which valve is best for your flow meter? Stefan von Kann, senior engineer in applied physics, provides a number of tips and tricks for the most pressing areas of attention.
2019 guest bloggers
We wish to thank our guest bloggers very much for their fascinating studies and compelling stories. It fills us with pride that you contributed content to our website in 2019.
• Roland Snijder, medical physicist resident at Haaglanden Medisch Centrum (NL), worked as a researcher on the multi-infusion project at the department of Medical Technology & Clinical Physics of University Medical Center Utrecht. In his guest blog, he focuses on investigating physical causes of dosing errors in multi-infusion systems.
• Jean-François Lamonier (University of Lille) is an expert in the catalytic treatment of volatile organic compounds. In this blog post, he explains how his team uses flow meters for this purpose.
• Jornt Spit, researcher at the Radius research group at Thomas More University of Applied Sciences in Belgium, has a background in biochemistry and biotechnology. He is working on renewable biomass. Read his blog post on controlled CO2 supply for algae cultivation and its valuable contribution as an alternative source of carbon.
• Prof. Michaela Aufderheide (Cultex Technology GmbH) has been working in the field of cell-based alternative methods with a focus on inhalation toxicology for more than 30 years. Increasing pollution of the environment and workplaces demands new testing methods. Read her blog post: ‘The e-cigarette – A blessing or a curse?’
Would you like to become even more inspired? All blog posts can be read on our website.
On behalf of the entire Bronkhorst team, I wish you a healthy, wonderful and innovative 2020!
Which topic would you like to be the focus of a blog post in 2020?
Please let us know
Anglian Water Services cleans water to the highest standard, delivers it to millions of homes, and carefully manages it to ensure it never runs out in an area of the UK. They started a project to optimize and further control dosing of phosphates in the public water system.
The functionality of orthophosphoric acid in the public water system
Public water systems commonly add phosphates to the drinking water as a corrosion inhibitor to prevent the leaching of lead and copper from pipes and fixtures. Inorganic phosphates (e.g. phosphoric acid, zinc phosphate, and sodium phosphate) are added to the water to create orthophosphate, which forms a protective coating of insoluble mineral scale on the inside of service lines and household plumbing. The coating serves as a liner that keeps corrosion elements in water from dissolving some of the metal in the drinking water. As a result, lead and copper levels in the water will remain low and within the norms to protect the public health..
What was the original process ?
In the original process a down-steam analyser was in-place to measure the concentration of orthophosphoric acid in the main flow. The measurement results were checked against the required concentration and used to adjust the pump speed and therefore the level of orthophosphoric acid in the main flow. With this process Anglian Water Services can secure copper and lead concentration levels in the water acceptable to protect the public health. Nevertheless the process had room for improvement, which will be discussed in this blog.
The original process of record
What are the limitations in the original process?
The reactive feed-back loop mechanism for dosing phosphates was not a preferred working method. We could not react quickly enough to the changing main flow to reduce or increase the dose proportionally. We had to ensure that we dosed to a level meeting the legal requirements assuming the station was processing maximum flow.
Secondary costs were added to the system by needing double redundancy on the analyser to ensure there is no break in the measurement of orthophosphoric acid levels.
- Reducing phosphate levels.
- Reducing the cost of meeting legal environmental standards for the business.
- Remove the downstream analyser and redundant spare in the process of record.
Two sensor technologies were evaluated to enhance the process ; Differential Pressure and Coriolis technology.
The Differential Pressure instrument was the most cost effective and allowed us to meter the Orthophosphoric acid flow as a volume, it would take an analogue signal input and adjust the dose proportionally to the main flow.
The Coriolis Mass Flow Meter utilizes direct Mass Flow Measurement, which is preferable over volume flow for this application and is more accurate and repeatable, but is more expensive. It would also take an analogue signal input and adjust the dose proportionally to the main flow.
Combination of mini CORI-FLOW with Tuthill pump
Making a decision appeared to be based around return on investment. Essentially the time taken to generate sufficient savings. However, during the demonstration of the Coriolis Mass Flow Meter we learned something new that would change the direction of our final design. The Coriolis Mass Flow Meter gave the density of the fluid being metered as an output.
Why was this important?
Phosphoric acid it sold in diluted concentrations , usually 80% in solution. What we have found is that there is a variation in the actual concentration at the point of use.
At this point we already knew that either the Differential pressure or Coriolis technology could support us to enhance the process of record. Now we had the chance to go to the next level and take a previously unavailable but very important parameter and use it to really refine the dose ratio.
The extra density parameter available with the Coriolis Mass Flow Meter made the decision for us. Dosing would now be controlled proportionally to the main flow and the density/quality of the phosphoric acid being used.
The enhanced process
What are the projected benefits using Mass Flow Meters:
As we look to go live on the first five installations of this technology, we are projecting the following:
- Stable concentration of orthophosphoric acid in the public water system.
- Maintaining the public health commitments of the Water Industry.
- Decreasing the addition of phosphoric acid into the environment by significant levels.
- Two-fold cost reductions: by eliminating the down-stream analysers and the consumption of phosphoric acid.
At Anglian Water Services they live with a Love Every Drop approach. The Love Every Drop approach is a vision for how they believe a modern utilities company should be run. That vision means creating a country with a resilient environment that enables sustainable growth and can cope with the pressures of climate change. Creating infrastructure that is affordable and reliable, meeting the needs of customers, communities and the environment. We want our people and our communities to be resilient too. Phosphoric acid is connected with the concept of planetary boundaries according to Rockström et al. 2009. Anglian Water Services was able to reduce the consumption of phosphoric acid in their processes without sacrificing the quality of the water. This fits with the way they run their business.
Our water treatment specialist are more than happy to help you face your challenges in water treatment. Send us your questions
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This weekend it’s the Easter Weekend! It’s the top selling season if you look at chocolate gifts. If you have a look in the supermarket now, you will find chocolate eggs, easter bunnies and bonbons in many variations. In our office we also have a large bowl filled with colourful chocolate eggs already, delicious!
And if we talk about various flavours of chocolate, that’s part were flow instruments come into the picture.
Chocolate confectionery industry
I would like to share my findings within the growing chocolate confectionery industry and the trends in using flavours. Who else can do this better than a woman you should think, as 75% of the women report that they indulge in chocolate, against 68% of the men.
Chocolate… a growing worldwide market of $100 billion once started with a simple choice between Milk, Dark or White chocolate. Nowadays the choice in variations is huge due to flavourings.
Chocolate as a seasonal gift is still very popular. Around the holidays we tend to buy more chocolate. The top selling season for chocolate is not Valentine’s Day, as you might think, but Easter. Besides treating yourself with chocolate, there is an emotional aspect. Chocolate can have a positive effect on your mood, especially with young adults. A popular reason for the increasing sales.
The majority of the chocolate buyers are looking for options with mix-ins as opposed to the conventional unflavoured varieties.
Flavour and textures
The global chocolate market has seen considerable innovation in flavour and texture. New product development continues to be imaginative, with more exploration of flavours and textures in addition to the traditional sweetness. However, the consumer base tends to be rather traditional as the most popular flavours still are Hazelnut, Caramel and Almond.
Older consumers tend to have a lower engagement with chocolate. The lack of interest reflects their desire to eat healthy. To regain this group of adult customers, companies have turned to tactics such as using alcohol flavours, organic ingredients, and premium positioning such as dark chocolate with Limoncello or chocolates filled with sweet liqueur.
It may come as a surprise, but a healthy lifestyle, which is one of the major trends worldwide, is also responsible for a substantial growth of the chocolate market and that’s not without reason. Chocolate, specifically dark chocolate with more than 85% cocoa, can offer beneficial health benefits. This results in labels mentioning:
- Rich in fiber, iron, magnesium, copper, manganese and other minerals
- Powerful source of antioxidants
- Protective against cardiovascular disease
The growing awareness of the health benefits of dark chocolate is one of the reasons why consumption of chocolate is increasing. With the rising popularity of dark chocolate, the sales for other variations are also going up. People are seeking other ‘healthy’ variations, such as sugar-free, gluten-free, kosher or fair trade chocolate. Due to these ethical claims, the industry has seen an enormous growth in variations.
In order to enhance a healthy image for chocolate, functional ingredients such as fibers, proteins, micronutrients, quick energy (guarana extracts), green tea extract, or chia seeds are more and more often added to the chocolate.
The increasing demand for chocolate also has its downside. About 3 million tons of cocoa beans are consumed annually of which more than 70% are produced by four West African countries: Ivory Coast, Ghana, Nigeria and Cameroon. Cocoa is a delicate crop and trees planted a quarter century ago have hit their production peak and the land they grown on are not as fertile as it once was. A large rehabilitation of land and trees is necessary to prevent the loss of crop production. Also climate changes are taking their toll.
This results in high costs for raw materials and unstable economic conditions in cocoa-producing nations. To prevent a supply shortage, a number of well-known chocolate producing companies have decided to invest in rehabilitation of the land and trees to make sure that cocoa will be available in the future.
This happens in a time that developing countries such as China, India, and Russia expect to increase their chocolate sales volume by 30%.
Mass Flow Meters in your production process
Due to the enormous growth of chocolate variations, using flavours and functional ingredients, mass flow meters and controllers find their way into the confectionery industry. Coriolis flow meters in combination with a pump are an ideal solution for dosing flavours and functional ingredients. Using the Coriolis instruments for additive dosing means less downtime between batches, traceability of ingredients, and higher product consistency and quality.
Watch our video about an additive dosing solution for the confectionery market.
Download our brochure (Ultra) low flow Coriolis competence for the confectionery industry.
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).
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
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.
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.
This week we have a guest blog from Dr. Roland Snijder, Medical Physicist Resident at Haaglanden Medisch Centrum (NL). To obtain his PhD degree at the Utrecht University, Roland worked as a researcher on the multi-infusion project at the department of Medical Technology & Clinical Physics of University Medical Center Utrecht (UMC Utrecht). His research focused on investigating physical causes of dosing errors in multi-infusion systems. In this research flow characteristics of multi-infusion setups were investigated using Bronkhorst Coriolis flow meters. In this blog Roland explains more about his research.
What is infusion?
Most patients admitted to the hospital are treated with medication (pharmaceuticals). Especially in critical care, a substantial amount of patients require intravenous therapy. Intravenous therapy means that a solution of pharmaceuticals are administered directly into the veins. The process of administering pharmaceuticals directly into the veins is called infusion and is done using a vascular access device (e.g. a catheter), which is inserted into the vein.
The importance of an accurate flow
Often patients in critical care, most notably young and premature patients, suffer from conditions that require the intravenous administration of very potent and short acting pharmaceuticals. These pharmaceuticals typically require a very accurate administration where deviations in flow- and thus dosing-rate can easily result in dosing errors. For this reason, infusion or syringe pumps are used.
On top of this, vascular access to the patient is typically limited and therefore many infusion pumps have to co-administer through one catheter (multi-infusion), making the entire pharmaceutical delivery process complex and hard to predict.
Because dosing errors are common in clinical practice, it was clear that more research was required. Many of the results of this research can be found in the PhD-thesis: “Physical Causes of Dosing Errors in Patients Receiving Multi-Infusion Therapy”.
Fig 1. Example of a multi-infusion setup in clinical practice.
Flow measurement with Coriolis flow meter
We conducted a large amount of measurements to learn more about the flow characteristics of multi-infusion setups. These measurements were conducted using Bronkhorst Coriolis flow meters (series mini CORI-FLOW. These flow meters allowed us to measure the flow rate of infusion pumps very accurately, precisely and independent of the density of the solution being measured (although most of the solutions were similar to water).
The flow meters were also chosen because of the suitability for very low flow rates, infusion flow rates may be as low as 0.1 ml/h. Ultimately it is, of course, the dose rate or mass flow rate of the pharmaceutical administered to the patient that is important.
To measure this we used an absorption spectrophotometric setup, which enabled us to measure the concentration of a substance in a solution, i.e. a pharmaceutical or pharmaceutical-analogue. To convert density (e.g. µg/l) to a mass flow rate (e.g. µg/h), the cumulative flow rate (e.g. ml/h) of the infusion setup has to be measured as well.
First we used a precision balance for this but later in the research project we used the mini CORI-FLOW flow meter. The data from the precision balance was rather noisy, whereas the flow meter provided very clean data, which improved our measurements substantially.
However, one point of caution that has to considered is that flow meters do produce a pressure drop resulting in intrinsic flow resistance. The implications of this and how the measurement setup relates to a clinical situation is thoroughly explained in the PhD-thesis.
The research concluded that a wide variety of infusion components all had a particular, usually significant influence and, importantly, medical personnel is usually not aware of the implications this has for infusion therapy. Awareness of the underlying mechanisms of these effects through education and technical innovation were recommended. The Coriolis flow meters from Bronkhorst proved to be very suitable for gaining insight in the different mechanisms of infusion pump system failure.
Further reading: R.A. Snijder - Physical causes of dosing errors in patients receiving multi-infusion therapy (ISBN: 978-94-028-0382-2)
About the author:
Dr. R. A. (Roland) Snijder (1985) is Medical Physicist Resident at Haaglanden Medisch Centrum (NL). He obtained a master’s degree in Biomedical Engineering at the University of Groningen with a specialization curriculum in the area of medical physics (medical instrumentation and imaging). In his master thesis, conducted at the University Medical Center Groningen, he investigated the effects of using computed tomography (CT) for lung cancer screening. After finishing his master thesis in 2012, Roland went on to pursue a PhD degree at the department of Medical Technology and Clinical Physics of University Medical Center Utrecht (UMC Utrecht).
Dr. Roland Snijder (HMC)
Want to learn more about calibration of infusion pumps? Read the blog of Marcel Katerberg, explaining the calibration techniques to improve infusion pump performance.
Let me start with explaining what demineralised water is. Demineralised water, also known as demi water, is purified water and is often used in laboratory applications for industrial and scientific purposes. However, also in your everyday life you will encounter applications with demi water.
For example for ironing your clothes with a steam iron, demi water can be used to avoid lime scale in your iron. But it is also used in car wash installations. A thin layer of demi water is sprayed over the car at the end of the car wash program to avoid dried up drops on your car. At the end of this document a few examples of the use of suitable Bronkhorst instruments are given.
Demineralised water versus distilled water
Demineralised water is water that has been purified in such a way that (most of) its mineral- and salt ions are removed. You can think for example of Calcium, Chloride, Sulphate, Magnesium and Sodium. Demineralised water is also known as demi water or deionised water. Demineralised water is generally considered different from distilled water. Distilled water is purified by boiling and re-condensing. In this way salt ions are being removed.
The major difference between demineralised water and distilled water is that distilled water usually has less organic contaminants; deionisation does not remove uncharged molecules such as viruses or bacteria. Demineralised water most times has less mineral ions; this is dependent on the way it is produced. Deionisation has a cleaner production and it leaves behind less scale in the installations it is used in.
A point of attention when using this demineralised water is the material of your instruments. Not all material is suited to serve as a piping material for demi-water; this also depends on temperatures that are used.
How is it made?
Demineralised water is produced via three main routes:
- Via Ion-exchange process using Ion exchange resins: Positive ions are replaced by hydrogen ions and negative ions are replaced by hydroxide ions.
- Via Electro-Deionisation also an Ion-exchange process takes place: An electric current is sent through the resins to keep them regenerated. The unwanted ions move away from the reaction surface to the electrodes.
- Via Membrane filtration: most times in multiple steps
To get the right quality of demi-water several stages of demineralization are necessary. The use of membrane filtration in this case has the advantage that in general no chemicals are needed to produce the demi-water (except perhaps for cleaning); the disadvantage is the amount of (electrical) energy consumed by the process.
Demineralised water – common uses
Demineralised water is used for industrial and scientific purposes. You can think of the following applications:
- Laboratory applications and testing
- Wash water for computer chip manufacture
- Automotive uses eg. lead-acid batteries and cooling systems
- Boiler feed
- Laser cutting
- Optimisation of fuel cells
- Steam irons and steam raising applications
- Pharmaceutical manufacturing
- Fire extinguishers
Health Risks of demineralized water
Demineralised water, which is completely filtered of minerals via (electro) ion-exchange, distillation, membrane filtration or other production methods, you would think that it could be used as drinking water.
However, as with all things, there are advantages and disadvantages to drinking demineralised water. The advantage is that the minerals that are bad for us have been taken out. There is a lot of documentation available about bad influences of certain minerals on our bodies. The big disadvantage of drinking demineralised water, however, is that demi water takes out also the good minerals from our body and causes a shortage so our health system cannot function properly anymore.
Summarised: demi-water should not be used for drinking water as it removes minerals that are needed for a good health.
Some examples of instruments which can be used for demi water
Coriolis flow meters, series mini CORI-FLOW
Ultrasonic flow meters, series ES-FLOW
- Thermal mass flow meters, series LIQUI-FLOW
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