All you ever needed to know about electromagnetic flowmeters

What is an electromagnetic flowmeter?

An electromagnetic flowmeter is a transducer that measures the flow of fluid using the voltage it induces as it flows through a magnetic field. Here at Bürkert, we can supply two different types of electromagnetic flowmeter products: insertion or full bore.

Within our range of electromagnetic flowmeters are the Type 8041 and Type 8045. These insertion electromagnetic flow meters feature an electronic module and either a stainless steel or polyvinylidene fluoride (PVDF) sensor. They are designed specifically for the measurement of flow rates in neutral or slightly aggressive fluids with a conductivity of more than 20 µS/cm. Suitable for pipe diameters ranging from DN06 to DN400, the Type 8045 is also suitable for CIP processes and FDA-approved versions are available.

Our full bore electromagnetic flow meter range includes the Type 8051, Type 8054, Type 8055 and Type 8056. These electromagnetic flowmeters feature a magnetic sensor fitting that connects to our Type SE56 transmitter, with the latter available with or without a display, depending on the version. All of our full bore electromagnetic flow meters are designed for liquids exhibiting a minimum conductivity of 5 μS/cm.

How do electromagnetic flowmeters work?

Electromagnetic flowmeters use Faraday’s Law to measure the flow of liquid in a pipe. The flow of a conductive liquid through a magnetic field causes a current flow between the two electrodes on the flow tube walls, which is measured as a voltage. The voltage is proportional to the movement of the flowing liquid. So the faster the fluid flows, the more voltage is generated. The electromagnetic flowmeter processes the voltage signal to determine liquid flow.

Full bore electromagnetic flowmeters employ an electromagnet, which is mounted perpendicular to the flow direction on the outside of the pipe. As the flow passes through the magnetic field, there is an accumulation of electrically charged ions. Negative ions accumulate on one side and positive ions on the other. The subsequent voltage change is directly proportional to the velocity of the fluid passing through the pipe.

Insertion electromagnetic flowmeters work slightly differently to their full bore counterparts. A localised magnetic field is inserted into the flowmeter. Two electrodes positioned perpendicularly to the magnetic field come into contact with the liquid. This causes charge bearers to separate and the electromagnetic flowmeter to sense the voltage and provide a flow measurement.

Advantages of electromagnetic flowmeters

Insertion electromagnetic flow meters, like the Type 8041 and Type 8045, offer a number of advantages. These innovative electromagnetic flowmeters feature sensors constructed from FDA-approved materials, have no moving parts, and excel in CIP applications. Both flowmeter models come with G2” connections in the PVDF sensor versions, while an optional extra clamp connection is available for stainless steel sensor versions.

Continuous measurement and batch control are entirely possible using any one of our full bore electromagnetic flowmeters. This makes them applicable for a number of applications, including water treatment, food and beverage or pharmaceutical. When combined with an actuated valve, these adaptable electromagnetic flowmeters are ideal for flow measurement and controlling high-precision dosing operations.

Disadvantages of electromagnetic flowmeters

As with any instrument, electromagnetic flowmeters do have some disadvantages to be aware of when considering your purchasing options. It is worth bearing in mind that the installation and commissioning of an electromagnetic flowmeter can be more complicated than other flowmeters.

Also, when an electromagnetic flowmeter is used to measure a viscous liquid, sediment and residue can adhere either to the inner wall or the electrodes. This can affect the output potential of the transmitter, increasing the likelihood of measurement errors.

Electromagnetic flowmeter applications

Electromagnetic flowmeters are suitable for a diverse range of applications, including:

• Irrigation.
• Waste water treatment.
• Flow regulation of drinking water.
• Drinking water supply in buildings.
• Pump protection and flow control in swimming pools .
• Measuring and control of water consumption is laundry facilities.
• Monitoring of cleaning cycles in the food industry (FDA approval).
• Applications with sea water, e.g. in desalination plants and fish farming.

Where can Bürkert electromagnetic flowmeters be used?

Electromagnetic flowmeters in the Bürkert range have been designed to meet the specific requirements of numerous fields of application. As such, we are certain to have an applicable electromagnetic flowmeter for your needs. 

• Type 8041 (stainless steel sensor) – For pressures of up to PN16 and temperatures up to +150°C.
• Type 8045 (stainless steel sensor) – For pressures of up to PN16 and temperatures up to +110°C.
• Type 8045 (alloy C22 electrodes) – For aggressive fluids and sea water applications.
• Type 8051 – For low flow volumes and Clean in Place (CIP).
• Type 8054/8055 – For water treatment and general-purpose applications.
• Type 8056 – For high-precision dosing operations and flow measurement when combined with an actuated valve.

Where can I buy an electromagnetic flowmeter?

Bürkert supplies a comprehensive selection of electromagnetic flowmeter products. For advice and guidance regarding specifying an electromagnetic flowmeter, or to discuss you application requirements in more detail, please contact our sales team today on +44 (0) 1285 648 720 or email sales.uk@burkert.com.