Nowadays, consumers are increasingly critical when it comes to healthy food and because of this, usage of natural products and ingredients is coming more into the consumer’s focus. Therefore, food and beverage producers worldwide have to react to fulfill the consumer and market needs.
Additive dosing
Unfortunately, natural ingredients are more expensive and harder to obtain in comparison to artificial or nature identical ingredients. So besides higher costs, important features for quality control must be considered. Reliability and reproducibility of the dosing method are important and often government-certified materials have to be used.
For most manufacturers, a variation in taste and colour is not acceptable.
Just have a look at the confectionery from the well-known brands; all lolly bags in supermarkets have the same colour and taste. This results in high requirements for guaranteeing the same product composition for every batch produced.
To fulfill the customer – and quality control requirements, as well as cost efficiency issues, it is necessary to redefine production processes.
Bronkhorst has developed a batch-dosing technology for fast and precise batch-dosing applications like additive dosing for confectionery applications.
Batch-dosing technology
The batch dosing technology, called Cori-Fill, is firmware that is integrated in all Bronkhorst Coriolis and ultrasonic flow meters and controllers. The technology features an integrated batch counter function with functionality to directly control shut-off valves, proportional valves or (gear) pumps. It’s a time and cost-efficient alternative to the more traditional gravimetric method.
This dosing technology allows dosing of small amounts of liquid additives with only a minimum of tolerance.
The firmware is equipped with a “learning function” to correct even the smallest tolerances automatically (e.g. during start-up of the instrument or change of supply batches). The setup is customised to fulfill all requirements of the production – it can be easily integrated in already existing production sites.
Additive dosing with a Coriolis flow meter
Besides the integrated batch dosing technology, all Bronkhorst Coriolis mass flow meters are equipped with an on-board PID-control for the direct activation of additional actuators – like valves and pumps – enabling fast communication and therefore enhances speed and quality of the control. The dosing speed is kept absolutely stable, even with long-term usage.
With a Coriolis instrument, the direct mass flow is measured (e.g. kg/h, g/h, g/min etc.). Furthermore, next to flow and temperature, the density can be measured as well. This can be monitored as an extra quality parameter.
Besides the Coriolis mass flow meter, another product in the Bronkhorst product portfolio designed for dosing applications is the ES-FLOW ultrasonic flow meter for measuring low-volume flows of liquids.
Similar to the Coriolis instruments, these flow meters comprise the batch-dosing firmware and on-board PID control. The hygienic design, namely a self-drainable straight sensor tube, an adequate surface roughness and the absence of any dead volume, make it suitable for the food and beverage industries.
This volume flow meter uses an innovative ultrasonic wave technology that can measure the flow.
Due to the integrated dosing technology in the ultrasonic or Coriolis flow meters, it is possible to dose expensive liquids like natural flavours, fragrances, colourings or acidifiers with a great reproducibility and accuracy to avoid production fails and unwanted waste of ingredients.
Both the Coriolis and ultrasonic instruments have their own specific characteristics.
The Coriolis instruments are more accurate (0.2 per cent of reading against 1 per cent of reading of the ultrasonic) but the ultrasonic has a more hygienic design (straight sensor tube, better surface roughness, no dead volume and therefore easier to clean).
Free software tools available for Bronkhorst Coriolis and Ultrasonic flow meters.
Various software tools are available to support the operation of these instruments. These software tools are suitable for operation by personal computers and available free of charge. Typical functions of this software include:
• Re-ranging the instruments
The Coriolis and ultrasonic instruments are linear, hence the instruments can be rescaled at any desired value within the specifications of the instrument.
• Optimising proportional-integral-derivative (PID) controller settings These flow meters and controllers have an integrated PID controller. Therefore, it is possible to control valves and pumps directly. With the software it is possible to optimise control settings to personal preferences and save them. This can be useful if users would like to use the same instrument for multiple processes.
• Printing a hardcopy of graphs
Share your results with colleagues and/or customers.
• Data logging to comma separated files
All parameters can be logged; therefore, you will have good traceability of your process. This is useful when it comes to quality assurance.
• Batch counter settings
The Coriolis and ultrasonic instruments are equipped with high-performance, batch-dosing technology. The counter function ensures that the actuator will react as soon as the batch has been reached. Normally, several components would be needed to achieve this. The integrated batch technology offers this functionality in one assembly without the need of additional hardware or complex programming.
The operating principle of a Coriolis flow meter is basic but effective. The flow meter contains a tube, which is energised by a fixed vibration.
When a fluid (gas or liquid) passes through this tube the mass flow momentum will cause a change in the tube vibration, the tube will twist resulting in a phase shift. This phase shift can be measured, and a linear output derived proportional to flow.
As this principle measures mass flow independent of what is within the tube, it can be directly applied to any fluid flowing through it – liquid or gas – whereas thermal mass flow meters are dependent of the physical properties of the fluid.
Furthermore, in parallel with the phase shift in frequency between inlet and outlet, it is also possible to measure the actual change in natural frequency.
This change in frequency is in direct proportion to the density of the fluid – and a further signal output can be derived. Having measured both the mass flow rate and the density, it is now possible to derive the volume flow rate.
The operation of Bronkhorst ES-FLOW flow meters is based on the propagation of ultrasound waves inside a small, straight sensor tube with an inner diameter of 1.3mm, without obstructions or dead spaces.
At the outer surface of the sensor, tube multiple transducer discs are located, which create ultrasonic sound waves by using radial oscillation.
Every transducer can send and receive, therefore all up- and down-stream combinations are recorded and processed. By accurately measuring the time difference between the recordings (nanosecond range) the flow velocity and speed of sound is calculated.
Knowing these parameters and the exact tube cross-section, the ES-FLOW ultrasonic flow meter is able to measure liquid volume flows.
The distinctive character of this flow meter is that it is capable to measure the actual speed of sound, meaning that the technology is liquid independent and calibration per fluid is not necessary.
Next to that, the speed of sound can be used as an indicator of the type of fluid present in the flow meter.