Sandra Wassink
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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.

Chocolate production

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.

Coriolis flow meter dosing block

Healthy lifestyle

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.

Cocoa

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.

Rob ten Haaft
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If we want to live healthy lives, we need to know the nature and content of undesirable chemical elements in our environment. If a municipal council wants to clean up a piece of land to develop a new suburb, it needs to know whether heavy metals or toxic substances such as arsenic remain in the soil from the previous use of the land. Likewise, the managers of drinking water sources, surface water bodies and fishing areas need to know about the quality of their water, to determine whether it contains excessive levels of undesirable substances that will have to be removed. And in order for air quality to be considered good, the trace element content in the solid particles floating in the air must not be too high.

Outside of the environmental field, there are other places where it is helpful to be able to identify and quantify the elements that are present – such as establishing the concentration of metal in lubricating oil to determine how quickly an engine will wear out, or the concentration of fertilisers in agricultural soil to determine whether additional fertiliser is required. Flow meters and regulators also play a major role here. As an industry specialist in the analytical market, allow me to explain how it all works.

Inductively Coupled Plasma – Atomic Emission Spectrometry, ICP-AES

As you can see, there are many applications in which it is useful to know what chemical elements are present and in what quantities. ICP-AES is a good analytical technique for measuring the nature and concentration of elements in solids, liquids and gases. This acronym stands for Inductively Coupled Plasma – Atomic Emission Spectrometry. Due to its high accuracy – up to the ppb (parts per billion) range – ICP-AES is particularly well suited to analysing trace elements, i.e. very low concentrations. This technique is excellent for detecting metals (such as mercury) and metalloids (such as arsenic), and dozens of elements can be analysed simultaneously. But what is behind this technique – and how does the careful delivery of gases play a role?

Controlled supply of argon gas through a flow controller

The short version: The ICP-AES method of elemental analysis uses an inductively coupled plasma to produce excited atoms and ions of the elements in the sample to be measured, whose characteristic spectrum is measured using atomic emission spectrometry (AES) as they return to their ground state. The intensity of the lines in the spectrum is directly proportional to the concentration of the elements in the sample.

The ICP-AES equipment can only analyse samples in liquid form. That’s not really a problem for water, but things get a bit tricky with soil samples and other solid substances. To unlock the chemical elements, you have to dissolve the sample in a strong acid: aqua regia, a mixture of hydrochloric acid and nitric acid. A peristaltic pump sucks the sample liquid out of a storage vessel and transports it to the nebuliser, which turns the liquid into an aerosol form or mist. To accurately regulate the concentration of the mist – and to dilute it if necessary – a flow of argon gas is supplied to the nebuliser, with the assistance of a flow controller. The mist then enters the reactor chamber, where it collides with the plasma that is already in the chamber.

If you supply a gas with sufficient energy – by passing a high electrical voltage through the gas using a coil – then some of the gas atoms release electrons. In addition to the original gas particles, you now have a mixture of negative electrons and positively-charged ions. This ‘ionised gas mixture’ of charged particles is called a plasma; plasma is considered to be the fourth state in which matter can exist, in addition to the solid, liquid and gaseous states. With ICP, argon gas forms the basis for the plasma, and this gas must be supplied with great precision, using flow controllers. The plasma has a very high temperature of around 7000 degrees Celsius. Because the plasma must have the correct composition at all times, a precise and continuous flow of argon gas is important. And to protect the outside world from this high temperature, a cooling gas (often but not always argon) is channelled around the outside of the reactor.

Regulating the mist

When the mist with the chemical elements to be measured collides with the plasma, these elements are also converted into plasma. The elements absorb so much energy that they enter an excited state. Elements don’t like to be in an excited state, so they try to return to their ground state at a lower energy level. During this transition, the elements emit radiation that is characteristic of each element. This radiation is measured by a spectrometer, and the intensity of the measured radiation is directly proportional to the amount of the element in question in the sample. Since each element has its own characteristic set of wavelengths of the emitted radiation, you can use this technique to identify multiple elements at the same time. And if you have a calibration curve for the elements concerned, or if you entered an internal standard into the nebuliser earlier in the process, then you can also quantify these amounts.

Spectrometer, ICP-AES or ICP-OES

The spectrometer within the AES part is a combination of mirrors, prisms, bars, monochromators/polychromators and detectors, which guide and ultimately measure the emitted radiation. To prevent any disruption to this process – such as the absorption of radiation by gases containing oxygen – the area where these optical objects are located is continuously flushed with nitrogen. This gas flow does not have to be very precise, but it does have to be highly reproducible. The use of flow controllers is essential to ensure this reproducibility. Incidentally, you may come across the term ICP-OES (optical emission spectrometry), which is an alternate name for ICP-AES (atomic emission spectrometry). These are two different names for the same technology.

ICP-MS

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ICP-MS is a similar technique for elemental analysis; the biggest difference is that the method of detection is not optical. The charged particles from the plasma enter a mass spectrometer (MS); here, they are separated on the basis of their mass-to-charge ratio, and the relative ratio of each of these charged particles is recorded. ICP-AES is performed at atmospheric pressure, but ICP-MS requires a vacuum. The detection limit for ICP-MS is lower than for ICP-AES.

In an environmental analysis, you can look not only at the total quantity of an element in a sample, but also at whether the element occurs in its free form or as a component of a chemical compound. By way of illustration: inorganic arsenic compounds are often more toxic than their counterparts in organic compounds. You can use ICP-AES and ICP-MS to distinguish between different forms of elements, a process known as ‘speciation’. However, this requires the different forms to be separated from each other before the ICP process, for example through ion exchange chromatography (IC). For this reason, the IC/ICP combination is very common.

Mass flow meters and flow controllers for ICP-AES

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When ICP was first invented, the gases were added manually. When ICP became automated gas regulation was automated too, and mass flow meters were introduced. Mass flow meters and flow controllers are devices used in ICP-AES to supply inert gases. If you have good gas regulation, the entire system is more accurate and more stable, enabling lower detection limits. Which is helpful, given the increasingly strict quality and environmental standards.

Bronkhorst supplies flow meters for the analytical market; our customers include a number of large suppliers of analytical equipment. These customers are often supplied with specific ‘manifold’ solutions. In these solutions multiple functionalities are integrated into a single body, custom built for the customer. Compact instruments with small footprints are becoming more and more important in laboratories where space is increasingly restricted.

Read the application story “Controlled supply of gases in Inductively Coupled Plasma (ICP-AES) for environmental analysis”.

Jos Abbing
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Industrial low flow applications have to cope with a wide variety of environmental and process conditions, but what does this mean when we talk about ‘industrial’? Knowledge about the specific application and low flow fluidics will help a lot to prevent slipping.

We often refer to ‘uncontrolled macro-environments’ for equipment, when we talk about ‘outdoors’. However, it can also be a room or factory without (local) climate control in which equipment is experiencing comparable temperature and humidity variations as outdoors.

What is important in low flow applications and what kind of challenges do you encounter? Let me share my ideas in this blog.

What is IP-rating?

I experienced that IP-rating is not always interpreted correctly. Having the highest possible IP-rating is often mistaken with having an ‘industrial-device’. But what does the IP-rating actually indicate? The first digit of an IP-rating only refers to dust ingress protection and the second digit refers to the liquid ingress protection.

Therefore, a higher IP-rating does not always mean that the instrument is better and more suitable for your application. Hence, it can even make things much worse in practice. A reason for this is that even the tightest IP-rated constructions may breathe in and out, caused by internal and external temperature variations. This can lead to internal condensation, especially in high humidity environments, if no further precautions are taken.

The importance of dedicated low flow equipment

Not surprisingly, things are often a lot smaller in low flow applications. The other side of this coin is that common process and environmental disturbances have a proportional larger impact on these low flow applications compared to traditional ‘normal’-flow applications.

In general, an industrial flow instrument, like a flow meter, needs to be suitable to a lot of external influences, such as resistance to corrosion and impact or pressure ratings. These requirements often lead to selecting more standard industrial flow meters instead of specialised low flow instruments. This is not always the best solution for the required low flow ranges and can lead to unsatisfactory results.

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What we want to achieve is to have rigid flow measurement and control, suitable for the application during the economic lifetime of the installation. Therefore, it would be best to select the best flow instrument fit for purpose. In case of low flow applications I therefore recommend to use dedicated low flow equipment. These flow meters are designed and tested for these kinds of applications. Our industrial low flow mass flow meters and controllers can be equipped with integrated control valves or dedicated pumps, especially designed for low flow purpose. Stable control characteristics are combined with signal-to-noise ratio plus being proportionally less sensitive for disturbances. Bronkhorst industrial low flow instruments We gladly support you in process and environmental equipment selections including system design aspects, starting with selecting the most suitable measuring and control principles. Our flow meter product portfolio contains laboratory-style and light-industrial flow meters to heavy-duty IEC-Ex/ATEX-rated industrial versions (…having a “high” IP-rating as well).

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Drive your low flow control reliable and safely!

Our product manager for liquid technologies, Ferdinand Luimes, explains how to deal with vibrations using Coriolis mass flow meters

Visit us at the Hannover Messe (April 1-5, Hall 11, booth A50)) and have a sneak preview at our new industrial Coriolis flow meter.

Kevin van Dijk
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For most people the classic summer treat is ice cream. Around 7 billion gallons of ice cream and other related frozen desserts are produced every year worldwide, with production peaking (as you might expect) in the summer months, according to the International Dairy Foods Association. Yet, the moment you consume an ice cream, you will probably not wonder how this delicacy is being made. To get that perfect ice cream, a mass flow controller is often used.

What does ice cream have to do with mass flow meters?

Ice cream contains many different ingredients, such as fat, sugar, milk solids, an emulsifying agent, flavouring and sometimes colouring agents. But there is one main ingredient that you may not have thought about, probably because you can’t see it—air. Ice cream is made by freezing and simultaneously blending air into the ingredients. So why is air so important?

If you have ever had a bowl of ice cream melt, and then refroze it and tried to eat it later, it probably did not taste very good. Moreover, if you leave a carton of ice cream out in the hot sun and let it melt, the volume of the ice cream would simply go down. Air makes up anywhere from 30% to 50% of the total volume of ice cream, therefore, aeration in the production process is crucial.

The amount of air in ice cream (often called overrun) affects the taste, texture and appearance of the finished product. Higher aeration will produce a tastier and smoother ice cream. A side effect of adding air to ice cream is that it tends to melt more quickly . Thus, for attaining an optimal structure of the ice cream, it is important to have a stable inlet air flow in the production process with a constant cream/air ratio. This can be achieved by using a mass flow controller.

The process of whipping ice cream into shape

To guarantee the right consistency and structure which ensures a full flavoured ice cream, the cream must contain the correct proportion and composition of air bubbles. Hence, aeration mixer manufacturers use a mass flow controller to dose an exact amount of air into the cooled mixer. Such a mass flow controller will ensure a continuous air delivery, proportional to the cream flow . The mass flow controller must be capable of maintaining its performance regardless of any possible back pressure variation. Occasionally, a check valve is mounted downstream of the mass flow controller. If inlet pressure drops, such valve will avoid ice back stream into the instrument. A pressure meter is also used with the purpose of monitoring the inlet pressure.

flowschemeofwhippingicecreamprocess

The SEM (Scanning Electron Microscope) picture below shows the ice cream microstructure. Air bubbles are a critical ingredient. Experts claim its optimal size, distribution and quantity are one of the secrets for having a creamy texture recipe. Hence, according to meet such demands, Bronkhorst has provided efficient solutions for enhancing continuous aeration processes.

Ice cream structure

So, the next time you head to the ice cream parlor with your friends, be sure to keep in mind the importance of Bronkhorst when it comes to that delicious refreshment.

EL-FLOW select

  • Watch the video about the EL-FLOW Select to learn more about the thermal mass flow instrument which can help you create ice cream.

Want to stay up to date on new flow solutions? Every month the latest tips in your e-mail box.

Graham Todd
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When you install a mass flow meter or mass flow controller it is important that you get the best performance from the moment you install and turn it on. To help you, I have listed a few simple things you can check focusing on thermal mass flow meters and controllers for gases.

1) Mounting position of flow meter

The mounting position is important. For flow meters the preferred position is horizontal, and at high pressures ( > 10 bar for by-pass instruments) all meters should be mounted in this position. Avoid installation in close proximity to mechanic vibration and heat sources.

2) Avoid interruptions

Avoid abrupt angles – or any objects in the flow path which can cause turbulence - directly on inlet and outlet of your flow instrument, especially for high flow rates. We recommend at least 10x the pipe diameter as the distance between the angle and the inlet of the flow instrument. If you are interested in why the choice of piping is important for thermal mass flow meters, please read our previous blog for more tips.

3) Name plate (serial number label)

Read the instrument’s name plate before installation and check the electrical connection, flow range, media to be measured, inlet and outlet pressure, operating temperature, ATEX classification (when applicable), as well as input and output signals. Also check the sealing material for compatibility with the process gas.

4) Electrostatic discharge (ESD)

The flow instrument contains electronic components which are sensitive to electrostatic discharges (ESD) – a sudden flow of electricity between two electrically charged objects caused by contact. Contact with electronically charged persons or objects could possibly endanger these components or even result in their failure.

5) Pressure

Do not apply pressure until electrical connections are made. When applying pressure to the system, take care to avoid pressure shocks and increase pressure gradually.

6) Check the piping

Ensure that the piping of the system is clean (before installing the instrument). For absolute cleanliness always install filters to ensure a moisture and oil-free gas stream. It is recommended to install an in-line filter upstream of the mass flow meter or controller, and if back flow can occur, a downstream filter or check valve is recommended too.

7) In line installing

Install the mass flow meter or controller in the line and tighten the fittings according to the instructions of the supplier of the fittings.

8) Piping diameter

Avoid small diameter piping on high flow rates, because the inlet jet flow will affect the accuracy and may cause too high pressure drops over the piping and adaptors. Choosing the right piping diameter is also of importance to minimize the effect of turbulence as much as possible. Our previous blog describes the effect of turbulent flow and what to do about this.

9) Leak testing

Always check your system for leaks, before applying fluid pressure. Especially if toxic, explosive or other dangerous fluids are used.

10) Power up

Apply power to the flow meter or controller and allow for approx. 30 minutes to warm-up and stabilize. This may be done with or without fluid pressure, applied to the system.

I hope that this list is of use. Please feel free to use it as a reference for the next time you need to install a mass flow meter or controller. If you have further questions or if you think I have left anything out then please let me know. At Bronkhorst, we are happy to learn from your experience.

Check the frequently asked questions (FAQs) on our website.

Or download the manual or quick installation guide of the flow instrument.

Wouter Sparreboom
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In this blog I would like to share the development of a MEMS-based Coriolis instrument, currently the lowest flow measuring Coriolis mass flow sensor in the world. MEMS is short for Micro Electro Mechanical System. This unique Coriolis instrument is available for field tests now.

MEMS (Micro Electro Mechanical System) technology

MEMS technology is similar to semi-conductor technology, but it is applied for sensors and miniature mechanical components instead of electronic chips. Well known applications of MEMS technology are airbag sensors, inkjet heads, pressure sensors, microphones, compasses, accelerometers, gyroscopes and time-base oscillators. For instance, a smartphone contains a lot of MEMS components and thermal flow sensors are widely used in air conditioning systems.

Wafers

Wafers, extremely flat circular discs

MEMS chips are made from wafers. Wafers are extremely flat circular discs, made from Silicon or glass. A typical wafer has a thickness of 0.5 mm and a diameter of 6 inch. MEMS technology is all about adding layers and removing those layers in certain areas. The layers that are applied can be of very high quality and robust materials. Silicon Nitride is an example of such a material, which is applied by Low Pressure Chemical Vapor Deposition (LPCVD) and it is performed around 800˚C.

Photo-lithography is used to define the areas that need to be removed. In photo-lithography, a layer of photo-resist is deposited on the surface of the wafer. The photo-resist is chemically altered by shining light on its surface and is selectively removed in a development solution.

Advantages of a Coriolis sensor

Most MEMS flow sensors are based on a thermal measurement principle. It has been demonstrated that such sensors are capable of measuring liquid flow down to a few nanoliter per minute. Advantages of these sensors are that they are fast and very stable. A disadvantage is that they need to be calibrated for each specific fluid. A Coriolis type of flow sensor, i.e. flow sensors containing a vibrating tube in which a mass flow is subjected to Coriolis forces, do not have this problem. The Coriolis forces are directly proportional to the mass flow and independent of temperature, pressure, flow profile and fluid properties since Coriolis flow sensors measure true mass flow.

Coriolis flow sensor

Coriolis flow sensor

Coriolis flow meters are mostly used for measuring large flow rates (>1 kilogram per hour), since the relatively weak Coriolis forces are correspondingly harder to detect for small flows. In order to gain enough sensitivity to measure ultra low flows below 2 gram per hour, the sensor size and tube wall thickness needs to be minimized to the extreme, which is not possible by conventional machining of stainless steel.

Here MEMS technology comes into play. A process called “surface channel technology”, which we developed in close collaboration with the University of Twente, allows for the fabrication of tubes with 1 micrometer thin Silicon Nitride walls. The choice of material renders these tubes mechanically stable even at this extremely thin wall thickness.

Principle of operation, MEMS based Coriolis sensor

In picture 3, the principle of operation of the MEMS based Coriolis sensor is explained. The sensor that is built into the demonstration model is based on this technology. The demonstration model can measure and control gas and liquid flowrates from 0.01 up to 2 gram per hour.

Coriolis flow sensor tube

The Coriolis flow sensor tube. The tube is brought into resonance by Lorentz actuation. The Coriolis force Fc is a result of the mass flow Φm through the tube

As an additional advantage of MEMS technology, the Coriolis tube inside the instrument has such small dimensions that the resonance frequency of the tube is in the kHz range. This results in a lower susceptibility to external vibrations than conventional stainless steel Coriolis instruments.

Demonstration models micro-Coriolis technology for field tests

We currently offer demonstration models of the micro-Coriolis sensor technology equipped with an on-board communication interface allowing integration into any application available. This demonstration model is called the BL100 and is available with and without valve for flow control. We see applications for the BL100 in microfluidics, such as life science, lab on a chip, medical dosing, chemical micro-reactors, catalyst dosing, pump calibration. We are also eager to learn more about applications from customers.

Interested in receiving a demonstration model?

Please contact us at [email protected] to request more information or a demonstration unit of this technological breakthrough in Coriolis mass flow measurement and control.

BL100 mini-Coriolis

BL100; demonstration model micro-Coriolis technology for field tests

Sneak preview next MEMS blog: Surface channel technology

The “surface channel technology” that is used to create the micro-Coriolis sensor chip allows for other types of sensors as well. Examples are: pressure sensors, density sensors, viscosity sensors and thermal mass flow sensors. Stay tuned for new blogs regarding this technology!

Read more about using MEMS technology in gas chromatography equipment in our November blog.