The inductive flow measurement is a common method for measuring the speed of conductive liquids in closed pipes. It is used in many branches of industry as it is contactless and therefore wear-free. In the following, we explain how inductive flow measurement works, explain its areas of application and give tips on what you should consider when purchasing such a measuring device.
Functionality of inductive flow measurement
Inductive flow measurement is based on Faraday's law of electromagnetic induction. This states that a voltage is induced in an electrical conductor that moves within a magnetic field and intersects the magnetic field lines. In flow measurement, the liquid to be measured acts as an electrical conductor, while the magnetic field is generated by electromagnets located outside the measuring tube.
The measuring tube is typically coated with a non-conductive material to ensure that only the liquid is affected by the magnetic field. Electrodes are attached to two points on the tube that are perpendicular to the magnetic field and the flow path of the liquid. When a conductive liquid flows through the tube, a voltage is induced at the electrodes in accordance with Faraday's law. This voltage is proportional to the speed of the liquid and therefore to the volume flow.
Advantages of the non-invasive measuring method of flowmeters
Inductive flowmeters are particularly advantageous in many areas of application due to their non-invasive measuring method. In contrast to invasive methods, in which sensors or measuring devices come into direct contact with the liquid to be measured, inductive technology measures the flow through the pipe without penetrating it and without introducing components into the liquid flow.
Advantages of non-invasive flow measurement:
- No interference with the medium: As no parts of the measuring device interfere with the liquid, there is no risk of contamination or interference with the medium. This is particularly critical in the food, beverage and pharmaceutical industries, where purity is essential.
- Reduced maintenance: Inductive flow meters are largely maintenance-free, as there are no moving parts that come into contact with the process medium and can wear out. This reduces maintenance effort and costs.
- Greater reliability: A non-invasive measuring method minimizes the risk of failures due to wear or deposits, which often occur with mechanical flow meters, for example.
- Simple installation and operation: The installation of inductive flow meters is uncomplicated because no complex interventions in the pipe system are necessary. This means they can also be easily integrated into existing systems at a later date.
- Application in aggressive media: As the measuring device itself does not come into contact with the liquid, inductive flow measurement can also be used with aggressive, corrosive or high-purity media without material fatigue being a problem.
The non-invasive nature of inductive flowmeters makes them an ideal choice for a wide range of industrial applications where reliability, hygiene and low maintenance are paramount.
Application areas of inductive flow measurement
Inductive flow measurement is ideal for liquids with a certain minimum conductivity, as is often the case in the following areas:
- Water treatment and wastewater treatment
- Chemical and pharmaceutical industry
- Food and beverage industry
- Power plants and mining
- Pulp and paper industry
This technology is often used when it is necessary to measure the flow rate of aggressive media or dirty liquids, as no moving parts come into contact with the measured medium and therefore no wear occurs.
What you should consider before buying an inductive flowmeter
- Conductivity of the liquid: Not every liquid is suitable for inductive flow measurement. The liquid must have sufficient electrical conductivity. Pure water or oils, for example, cannot be measured. Check the conductivity of your liquid before deciding on a measuring device.
- Material of the measuring tube and electrodes: The material of the measuring tube must be chemically resistant to the liquid to be measured. The electrodes and the lining of the measuring tube must also be selected so that they are not damaged by the liquid.
- Size and installation: The dimensions of the measuring device should be adapted to the pipeline to ensure accurate measurements. Pay attention to the manufacturer's specifications regarding the minimum and maximum flow rates as well as the installation conditions, such as the need for straight inlet and outlet sections.
- Temperature and pressure conditions: Ensure that the measuring device is suitable for the temperature and pressure conditions of the application. Extreme conditions may require special device designs.
- Integration into existing systems: Another important point is the compatibility of the inductive flowmeter with the existing measurement and control technology in your company. Find out about interfaces and communication protocols.
- Certifications and standards: Certifications and compliance with certain standards may be required for some applications, for example in the food and beverage industry or in the area of explosive atmospheres (ATEX directive).
Inductive flow measurement offers a reliable and accurate solution for volume flow measurement in many industrial processes. However, in order to select a suitable measuring device, it is important to consider the specific requirements of your application and, if necessary, seek expert advice.We at are happy to assist you with more than 30 years of experience in the field of industrial flow measurement at .
