Ron Tietge
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We still often struggle with doing the dishes, and sometimes we just want our dirty dishes to magically disappear. If you do not have a dishwasher yet, you will definitely recognize this problem. However, manufacturers do their utmost best to make dishwashing as colourful as possible. You have probably noticed the large variety of detergents in your supermarket, so many choices! Mass flow controllers play an important role in the production process of these detergents. Let me explain why…

Colouring detergents

Detergent itself is transparent or white in colour. To change this, a small amount of colourant (or dye) is added to detergent and that’s the colour you see in the bottle; often green, yellow or red. The colourant does not add anything to the cleaning properties, however, it makes it more attractive and it will help the user to recognize a certain brand. For the manufacturer a consistent colour of the end-product is of major importance. Every bottle has to be the same colour, you should not see any colour difference between the bottles on the shelves (as the colour is part of their company branding).

What would be an appropriate way to dose these colourants? Pump control can be your solution.

Using Coriolis mass flow meters for accurate dosing

Dosing colourants can be done by using a pump. However, since this is volume flow it is not always the most accurate way. In these kinds of applications accuracy, and moreover, repeatability are crucial for the production process.

Important requirements in applications using colourant are:

  • Accuracy: the colourants used are in fact highly concentrated and have to be applied in extremely low doses. Furthermore, the colourants are rather expensive; therefore accurate dosing of the liquid is very much desired as well.
  • Repeatability: every bottle of detergent has to have the same colour, therefore the dosing of the colourant has to be consistent, always.

A better solution here would be to combine your pump with a Coriolis mass flow controller; it will give you the opportunity to control your pump and therefore a precise and traceable way of dosing your colourant.

mini cori-flow + tuthill pump

Pump control

The unique method of combining your pump with a Coriolis mass flow controller makes the pump dose mass flow instead of the usual volume flow. Since real mass flow is independent of the fluid properties of the colourant, the accuracy will be inimitable.

A PID controller makes it possible to control the speed of your pump. This can be done by an external PID controller (however, this can result in a slow response and slow control) or by a Coriolis instrument with integrated PID controller (a separate control signal will control the speed of the pump).

Read more about pump control in my blog about using pump control to optimize detergent colour.

Coriolis mass flow controller with integrated PID controller

Bronkhorst has a Coriolis instrument in its portfolio with integrated PID controller. The advantage of using a Coriolis instrument with integrated PID controller is the so called ‘closed loop system’. The flow will be immediately corrected if there is a change in back pressure by making the pump run faster or slower almost instantly, keeping up the required accuracy.

Additional benefit of this stable control method is that the pump is made to run on a moderate speed, decreasing wear and thus increasing its service life, resulting in less downtime of production equipment. Dosing mass flow instead of volumetric flow means high accuracy, for all your available liquids.

example response time coriolis flow meter

Example of response time of a Bronkhorst Coriolis instrument (series mini CORI-FLOW) with pump. (red = set point, green = output and yellow is the fast control signal to control the pump).


Other applications where you can encounter these challenges with dosing colourants/dyes are in production processes of shampoos, soaps, fabric conditioner agents, (shaving) creams and tooth pastes. In a previous blog, I shared my thoughts about how pump control can optimize our detergent colour.

James Walton
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New Year's marks a time not only for resolutions, but also reflection. We are very delighted that our blogs have been received so well! This past year there were again many interesting stories to tell, how could it be otherwise given the industries in which we operate. I would like to share our top 5 best-read blogs of 2017 with you.

1) The importance of mass flow measurement and the relevance of Coriolis technology Why is Mass Flow Measurement important within process industries and what are the strengths of Coriolis Flow Meters and Controllers? Given the number of readers of this blog, this is a frequently asked question.

2) A typical day at Bronkhorst’s flow meter Calibration Centre We followed Mandy Westhoff, one of our Calibration Centre operators at our headquarters in Ruurlo, during her daily routines to get a realistic view on the activities of the Calibration Centre. A unique moment for readers to gain more insight about this challenging and important work!

3) How to measure low flow rates of liquids using ultrasonic waves? In June 2017 we were proud to launch our ultrasonic flow meter, the ES-FLOW™, for measuring and controlling liquid volume flows. In collaboration with TNO (Netherlands organization for applied scientific research) we were ably to develop this instrument using Ultrasonic Wave Technology. More in-depth information on this subject can been found in this blog post.

4) Bronkhorst, its share of a clean – solar – energy future Sustainability and clean energy remains a hot topic. CO2 reduction is one of the major trends worldwide in the energy market. The global focus on CO2 reductions matches perfectly within the Bronkhorst principles regarding respect for nature and environment.

5) How low can you go? Well, this recent blog of Marcel Katerberg is not very low on our rankings. If you are keen to learn more about how to handle ultra low flow, then you definitely should read this blog.

Furthermore, I would like to thank our guest bloggers of this year, who were so generous spending their time in crafting an interesting blog contribution.

Frank Nijsen (Quirem Medical), Bram de la Combé (Green Team Twente), Maarten Nijland (Veco B.V.), Jeremy Lowe and Ian Brown (Anglian Water Services), Jens Rother (Rubolab GmbH), and Kees Jalink (NKI – Netherlands Cancer Institute)

I am confident that you will enjoy reading these blog posts - if you haven't read them already. But for now, I wish you on behalf of our whole team great health, happiness and success in the coming year.

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Adam Mumford
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What is FLUIDAT?

FLUIDAT is Bronkhorst’s online calculation software. It allows our end users to make many theoretical calculations for their instruments and also have access to over 1800 different fluid properties and corresponding data.

Working with fluids and ever changing process conditions can provide many challenges, especially when trying to understand the behaviour of the given fluid depending on the actual pressure and temperature of the process. Along with understanding the behaviour of your particular fluid or fluid mixture making sure that you select an instrument that is able to operate effectively to the level you expect and that meets your application’s demands. In this case the initial selection of the correct instrument is fundamental, understanding what is possible for the future of your instrument can however be just as important.

This is where FLUIDAT can assist by allowing our end users to fully understand their instruments capability. If it’s working at different pressure conditions or using a completely different fluid for example, FLUIDAT can allow you to make an informed decision about whether or not the instrument is up for the task at hand. Of course, sometimes we have to accept that returning the instrument for recalibration is the only option but with FLUIDAT at your fingertips you have the ability to make an informed choice.

Traditionally, fluid data has been stored in technical handbooks and manuals with graphs and tables of data in a listed format demonstrating fluid properties along with their coefficients. However, this is a very inflexible format and does not allow immediate access to changing fluid behaviour (due to external factors) without making what can sometimes be complex calculations.

Knowing that these challenges were sometimes a hindrance to our end users, Bronkhorst released this on-line fluid management programme to support our customers in a way we never had before. This on-line programme allows immediate data and calculations relating to the behaviour of thousands of fluids under different working conditions.

One example of this is our Controlled Evaporation Mixing (CEM) vapour generation calculation tool. To calculate the output vapour to the process you need to calculate the combination and vaporisation properties of both a liquid and gas at differing temperatures and flow rates. Our CEM calculation tool can make this task easy, at just a click of a button.

The newly added interactive Vapour-Pressure line allows users to simply glide the cursor over the chosen fluid graph to establish the phase at the given temperature and pressure. Added value comes from the ability to create and save your own fluid mixtures, which alone can remove hours of calculations and research from a single project.

OK, so let’s have a look in more detail at some of the calculation tools available in FLUIDAT.

Gas Conversion Factor:

Here, the end user can choose a pure gas or create a gas mixture to find the conversion factor for a different gas to which an instrument can be sized on. As with most thermal mass flow controllers the output signal from the MFC is determined by which gas it has been calibrated for. With the gas conversion factor tool you simply choose the ‘Fluid from’ and ‘Fluid to’ to find out the conversion / correction factor. You can also select your exact model to improve the accuracy of the conversion. This function also allows you to add the specific pressure and temperature conditions you are converting from and to, for even more accuracy. The conversion factor can then be applied to the output measurement of the MFC to know the actual flow of the new gas.

Example of a gas conversion made in FLUIDAT: Image description

Controlled Evaporation Mixing (CEM) Calculation Tool:

A CEM system can be an extremely versatile addition to any vapour generation requirement. FLUIDAT allows the end user to make various calculations to not only enable the correct CEM heater temperature setting , the flow rates required for both the liquid and gas instruments and the relative humidity of the generated vapour. It is also possible to back calculate the flow rates needed to achieve the required relative humidity of your vapour. All of the fluid data is stored within the FLUIDAT software, the heat capacity, thermal conductivity and heat of vaporisation to name a few. This data can also be accessed by the user under the ‘Fluid Properties’ calculation.

The possibilities of the CEM calculation tool are endless, from knowing the pressures needed to supply the liquid and gas MFCs to calculating the vapour temperature on the outlet, or knowing the flow of the vapour output and having the ability to choose between thousands of different fluids to make your calculations. This makes FLUIDAT a ‘must-have’ for any Bronkhorst customer using our CEM vapour delivery systems.

Example of a CEM calculation in FLUIDAT: Fluidat CEM calculation

Pressure Drop Calculations:

For most applications it is important for the end user to understand the pressure drop across the instrument. It is not only important to understand the pressure loss across a device but sometimes it can also be critical to know the required pressure for the instrument to function correctly, especially when using control valves.

In FLUIDAT it is possible to calculate the pressure drop for both our gas instruments and our mini-Coriolis Series. Calculating the pressure drop using FLUIDAT is easy, all you need to do is select the correct pressure drop calculation tool. You have the choice of selecting our MASS-STREAM, EL-FLOW/IN-FLOW or Coriolis Instruments.

The calculation tool for the Coriolis Instruments is called ‘CoriCalc’ and for the other instruments are referred to as ‘Pressure Difference D-6300’ or ‘Pressure Difference LOW-dP-FLOW and EL-FLOW'. Once you have selected the correct tool and instrument type you can then select the fluid and flow rate and simply hit the calculate button. You can choose to readout the pressure drop in many different units from mbar to psi for example. For meters this is pretty straight forward, the pressure drop will be displayed across the sensor and fittings and yes, you can also choose the fitting size and type in many situations.

This calculation tool can also demonstrate the minimum required inlet pressure to flow the fluid you want at the required flow rate. Without the complication of the control valve calculating for meters is relatively straight forward. When making calculations involving both a meter and control valve (e.g. in a controller), it is important to make sure your calculation includes the correct selected orifice for your given controller, the easiest way to do this is using the inlet and outlet pressures to be used.

Example of a Pressure Drop Calculation in FLUIDAT: Fluidat pressure drop calculation

FLUIDAT is an extremely useful and powerful tool for those using Bronkhorst instruments. It allows an end user access to additional information which can be used to not only enhance the potential of our instruments but also allows our customers to gain an advantage over competitors and gain an understanding of mass flow. The above examples are just a snippet of some of the tools available.

Please register at to take full advantage of this free online software.