Insights from industry

"Field Time Control" Based Level Detection for Low Dielectric, Non-conductive Bulk Products

Louis Ras, Business Unit Manager for the Instrumentation Division at Fluidwell Instruments talks to AZoSensors about based level detection for low dielectric, non-conductive bulk products.

The Triflex LNI200 measures the level on the outside of a non-metallic tank without physical contact with the product. What inspired you to develop this sensor?

The design was formed after discussions with roller mill manufacturers in Italy. On top of roller mill machines there is a plastic buffer tank (photo). The purpose of the buffer tank is to let the unit operate continuously. The level of bran and flower is PID controlled: The higher the level, the faster the speed of the rolls.

Plastic buffer tank on top of roller mill machines.

Plastic buffer tank on top of roller mill machines. Image courtesy of Fluidwell Instruments.

They used a continuous capacitance probe and optical systems (stacked lasers). The reliability of the optical laser system was poor, because of the dusty environment. The traditional capacitance probe, on the other hand, was affected by the quality of the grain, as this is a natural product.

Due to this quality change, the inaccuracy could increase to 20% and in a PID controlled loop that leads to expensive production losses. Every measurement had its severe defects, therefore.

The manufacturers ideally preferred a continuous level measurement from the outside of the tank that was not affected by product quality changes. This is how the idea of the Triflex LNI 200 started, with stacked electrodes that individually measured the capacitance in a new way: Capacitance 2.0. We called this new technology FTC: Field Time Control.

FTC technology? How is that different from regular capacitance technology?

FTC (Field Time Control) is an innovative product detection technology designed for example bulk solids.

With FTC Technology a sensor’s sensitivity increases considerably, making it applicable for various bulk products, even with extremely low dielectric constants. And getting more signal with lower variation for increased reliability and thus decreasing costs, increasing revenues and clearer insight in running processes.

FTC is a new innovative technology where an electric field is generated between the transmitting and the receiving electrode. The cycle time of the FTC sensor changes as soon as a product intervenes this electric field. Applications with a sensor with FTC Technology provide a more reliable and cost-effective solution.

Field Time Control – FTC Technology.

Field Time Control – FTC Technology. Image credits: Fluidwell Instruments.

The amount of clock pulses is directly proportional to the measured capacitance. Even a slight capacitance change or a small level change results in a considerable increase of the amount of counted clock pulses, which makes the FTC technology more stable and reliable than traditional capacitive devices.

All Fluidwell Instruments products, also the Triflex LNI200, use this revolutionary FTC Technology, making it possible for even extremely low dielectric products to be measured.

The innovative digital cycle time conversion into FTC counts results in increased production output and reduced downtime for all applications using Fluidwell instrumentation with FTC Technology. FTC is a, what we call, Capacitance 2.0 technology.

Is the Triflex LNI 200 product a key device among your product line?

Naturally it is and for that reason we have patented it. We have high expectations as its innovativeness has great and positive implications for many producers in selective branches. The unique features of the Triflex make it easy to sell its added value compared to other less optimal “solutions”.

How does this product work?

The Triflex has a user-friendly single button set-up: After installation of the instrument, you just press the set-up button once, when the tank is empty. The system then ignores the plastic or glass tank wall and is up and running.

The LNI 200 device has 20 sensors distributed over the total length of the unit. So each sensor represents 5% of the total range. For each consecutive covered sensor the range value is increased by 5% and the loop current is increased by 16/20 is 0.8 mA.

Each of the stacked electrodes is, after being selected, measuring the capacitance information using FTC technology. As a result the system identifies which electrodes are covered by the customer’s product (bran, flour, medicine powder etc.) and as such accurately determines product levels.

Even with a hard-to-measure product with low dielectric constants and insensitive to changing process conditions, thanks to the FTC technology. Sounds simple, not? Technically it was quite a challenge though, which took many years of development, resulting in a patented product.

What would you say are the main advantages to this product that makes it stand out from competing products on the market?

The Triflex has several unique advantages that many users find very useful in their processes. Being able to measure levels without product contact is definitely one of the most important ones.

For sensitive products, like food and pharmaceuticals (contamination risks) and for aggressive product like acids, this is an absolute must these days. Contamination in food for instance, brings such great risks and thus responsibilities; it should be avoided at all cost.

Acids and abrasive products could only be measured at great cost (if at all) using equipment made from highly expensive materials, which still have to be replaced frequently. Or less refined equipment with highly inaccurate techniques is used.

Next, the FTC technology enables the Triflex to accurately measure low dielectric product, being insensitive to changing process conditions.

This stimulates higher output and reduces the cost for expensive additives. Other options fail under changing conditions and thus cannot generate an accurate reading.

Last but not least it is very profitable and the Triflex is mounted on the outside. This saves huge costs.

First in installation (no nozzles required – which also eliminates leakage risks), especially with its one button set-up, and second in maintenance: The unit is easily accessible from the outside, so any maintenance can be done without stopping the running process.

For many applications, there are just no other options available to come even close to the accuracy a Triflex can offer. This is apart from the savings achieved.

Since the introduction of the Triflex LNI 200, what has been the customer feedback and what impact has this product had on the market?

As was expected, the pharmaceutical and food industries were the first ones to try the new Triflex. After all, the birth of the Triflex started there!

To their great satisfaction the Triflex has added substantial value to their processes, like described already, especially since we adapted our products to the application in question when needed. Higher sensitivity, longer version, or want to measure upside down? You’ve got it.

Unfortunately we cannot reveal names for competitive reasons, as per their request. Safe to say is that the biggest international pharmaceutical companies in the USA, Switzerland and the UK use the Triflex at this moment. More projects are running in a number of countries (UK, Denmark, Belgium).

What are the power requirements and operating specifications for this product?

The operating specifications of the Triflex are as follows:

Loop Voltage up to 33 VDC nominally
Lift-off voltage at 4 mA ~  11VDC
Min. Operating voltage at 20 mA ~   9 VDC
Solid-state output   48 VDC/ 220VAC and 100 mA max
Loop current   conform to Namur NE43
4...20 mA (0-100%)
3.8 mA (saturating below 0%)
20.5 mA (saturating above 100%)
3.6 mA (fault current low value)
21 mA (fault current high value)

Each consecutive sensor covered increases the loop current by 0.8 m.

Are you planning on introducing any new products over the next five years?

Enlarging the Triflex family, several additions will be launched sooner or later. The LNI250 (suitable for conductive material) is to be launched any moment now, and a flexible version of all Triflex variants will come in a couple of years.

The biggest new innovation from Fluidwell Instruments, however, is expected somewhere next year, when we launch the Enigma for the oil industry. When you consider the Triflex is innovative, wait until you see the Enigma!

Again patented, the Enigma identifies the individual levels of the different layers in the separation processes of crude oil from all the other material (like water and sand). Its advantages are again staggering, with a potential of saving millions annually: A higher production volume, as the process speed can be turned up, less risks in environmental claims, less usage of expensive chemicals (like defoamers and demulsifiers) and less process shut downs.

It goes without saying that the biggest oil companies in the world are eagerly awaiting the Enigma. The field trials are planned this year.

Where would you say your company fits in the current market with regard to customer demand and innovation?

Fluidwell Instruments develops and manufactures high-tech process instrumentation for selected markets that require revolutionary measuring techniques, which add substantial value to the production processes of customers.

We are not involved in the mass market, commodity side of sensor instrumentation. When you are looking for a regular device for a simple measurement issue, there are many (big) companies that can do the job. We don’t want to play in that field. It’s when you have a complicated process or product (like low on dielectric constant), you will want to contact us for a solution, where others fail or just don’t want the (financial) risk.

We operate at the top of the instrumentation market, by constantly expanding it with new, pioneering technologies. When the going gets tough, you’ve got to have a Fluidwell! Louis Ras

About Louis Ras  

Louis Ras has close to 25 years of experience in the business. After extensive education in measurement and control, he started working for AkzoNobel. Via Yokogawa he ended up with Milltronics, which was acquired by Siemens in 2000. Since 2007 Louis Ras has been working at Fluidwell as Business Unit Manager for the Instrumentation division of this group.

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