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What are the installation standards for electromagnetic flowmeters?
Time : 2025-09-04
Electromagnetic Flowmeter Installation Instructions
Proper installation of an electromagnetic flowmeter ensures accurate flow measurement.
Are you ready to install your electromagnetic flowmeter? Then these electromagnetic flowmeter installation instructions are just what you need. These electromagnetic flowmeter installation instructions apply to electromagnetic flowmeters supplied by the JUJEA brand, made in China. If you have any questions about electromagnetic flowmeter measurement and installation, please feel free to contact us.
A magnetic flowmeter, also known as an electromagnetic flowmeter or EMF for short, is a positive displacement flowmeter that uses the principle of electromagnetic induction to measure the flow rate of a conductive fluid based on the electromotive force induced when the fluid passes through an applied magnetic field. A magnetic flowmeter has no moving parts. An electromagnetic flowmeter consists of two components: an electrode (sensor) and a transmitter. Installation options include integrated, split, and insertion types.
Electromagnetic flowmeters are primarily used to measure the flow of conductive media with good fluidity. Electromagnetic flowmeters are available in both insertion and in-line types. The installation requirements for both in-line and insertion types are the same.
Electromagnetic Flowmeter Installation Steps
The electromagnetic flowmeter installation process is simple.
Select the correct installation location.
Installation Inspection. After installation is complete, check the pipes for correct installation and the reliability of all connections, especially the ground wire.
Power on and preheat. After the electromagnetic flowmeter has been preheated for 20 minutes, it will begin measuring normally.
Zero tracking. To maintain the accuracy of the electromagnetic flowmeter, zero tracking is required. If the measuring tube of the electromagnetic flowmeter is filled with liquid, perform a zero calibration and then save (confirm).
Electromagnetic flowmeter installation basics
Select a straight pipe section filled with liquid. This can include a vertical section (preferably with flow from bottom to top) or a horizontal pipe filled with liquid (preferably at the lowest point of the entire pipe). During installation and measurement, ensure that the pipe is not partially filled.
The measurement location should be a straight pipe section greater than 5° upstream and 3° downstream.
The measurement point should be as far away from equipment such as pumps and valves as possible to avoid interference with the measurement.
The measurement point should be as far away from high-power radio stations and sources of strong magnetic fields as possible.
Installation Environment Requirements
- Electromagnetic flowmeters should be installed in locations with significant temperature fluctuations or where equipment is exposed to high-temperature radiation. If installation is necessary, insulation and ventilation measures must be implemented.
- Electromagnetic flowmeters are best installed indoors. If installation is necessary outdoors, they should be protected from rain, water, and direct sunlight, and moisture and sun protection measures should be implemented.
- Flowmeters, especially those with smart LCD displays, should be installed away from direct sunlight, and the ambient temperature should be between 5°C and 55°C.
- Electromagnetic flowmeters should not be installed in environments containing corrosive gases. If installation is necessary, ventilation measures must be implemented.
- To facilitate installation, maintenance, and servicing, sufficient space should be provided around the flowmeter.
- Electromagnetic flowmeters should be installed away from magnetic fields and strong vibration sources. If pipeline vibration is significant, the flowmeter should be supported on both sides. The flowmeter should be installed away from strong electromagnetic field radiation. Avoid equipment that may generate electromagnetic interference, such as motors, transformers, and frequency converters. The flowmeter's measurement principle is based on Faraday's law of electromagnetic induction, and the raw signal it generates is very weak, less than the millivolt level. Strong electromagnetic radiation near the flowmeter can affect measurement accuracy and even cause it to malfunction.
- Straight pipe length. Avoid components that generate eddy currents, such as valves, elbows, and bypasses. Extend the straight pipe length upstream and downstream of the flowmeter as much as possible. Install a rectifier if necessary. Ensure that the straight pipe length upstream of the flowmeter is greater than 5 DN (the diameter of the measuring pipe) and the downstream straight pipe length is greater than 2 DN.
- The conductivity of the liquid must be uniform and stable. Avoid installing the flowmeter where the conductivity of the measured fluid is extremely uneven. Injecting different media upstream can cause uneven conductivity and affect measurement. In this case, it is recommended to move the injection port downstream. If upstream injection is necessary, it should be as far away from the flowmeter as possible. Generally, a distance of at least 20 DN is recommended to ensure thorough and even mixing of the liquids.
- Keep the electrode axis horizontal. The measuring electrode surface must be horizontal. This prevents short-term insulation between the two electrodes caused by bubbles.
- No bubbles. Ensure that the flowmeter is installed in a piping design that does not introduce bubbles.
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The flowmeter piping is full. The flowmeter can be installed horizontally, vertically, or at an angle. However, the piping structure must ensure that the measuring tube is always filled with liquid (full pipe). When designing the piping, ensure that there are no bubbles in the measuring tube; otherwise, unstable measurements and excessive deviations will occur.
Electromagnetic Flowmeter Installation Pipe Section
Electromagnetic Flowmeter Straight Pipe Section Requirements:
The electromagnetic flowmeter must be installed horizontally on the pipeline (within a 50° inclination). During installation, the flowmeter axis (Verabar flowmeter line) must be concentric with the pipeline axis. Flow rates must be consistent.
The upstream pipeline of the electromagnetic flowmeter should have at least 2D of straight pipe of equal diameter. If the installation site permits, a 20D upstream straight pipe section and a 5D downstream straight pipe section are recommended.
Electromagnetic Flowmeter Pipe Section Requirements:
The inner diameter of the pipeline upstream and downstream of the flowmeter installation point must be the same as the inner diameter of the flowmeter.
Electromagnetic Flowmeter Bypass Pipe Requirements:
To ensure that flowmeter maintenance does not affect the normal flow of the medium, shut-off valves (shut-off valves) should be installed in the pipelines before and after the flowmeter, and a bypass line should also be provided. A flow control valve should be installed downstream of the flowmeter. When the flowmeter is in use, the upstream shutoff valve must be fully open to prevent unstable flow upstream.
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Installation Method
Electromagnetic flowmeters can be installed using flanges, clamps, and threads, with flange mounting being the most common. The following points should be noted during installation:
- The flowmeter should be installed at the bottom of a horizontal pipe, pointing vertically upwards; avoid installation at the highest point of the pipe, pointing vertically downwards.
- The flowmeter should be installed at the rising point of the pipe.
- If installed on an open discharge pipe, the installation should be at the bottom of the pipe.
- If the pipe drop exceeds 5 meters, an exhaust valve should be installed downstream of the sensor.
- The control valve and shutoff valve should be installed downstream of the sensor, not upstream.
- The sensor should not be installed at the pump inlet or outlet, but at the pump outlet.
- The installation location of the electromagnetic flowmeter should be determined according to actual site requirements, but the electrode axis must be installed horizontally.
- During field operation, the electromagnetic measuring tube must completely fill the pipe section. 9. The flow direction of the measured medium should align with the arrow on the electromagnetic flowmeter.
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If the measured medium contains solid particles or slurries, vertical installation (bottom-up flow) is recommended to prevent solid particle accumulation in the flowmeter tube.
Installation Requirements for Insertion Electromagnetic Flowmeters
- Pipe Straightness Requirements. Inlet and Outlet Straightness: Inlet should be ≥ 10 x DN; Outlet should be ≥ 5 x DN.
- Grounding Point Requirements. To ensure reliable meter operation and improve measurement accuracy, interference from external parasitic potentials must be avoided. The sensor should be well grounded, with a ground resistance of less than 10Ω. (If the metal pipe is well grounded, no special grounding device is required.)
- Select an insertion electromagnetic flowmeter based on the pipeline conditions. Where continuous loading and unloading is required or where overflow of the medium is not permitted, a ball valve must be installed. In other words, an insertion electromagnetic flowmeter with a ball valve structure should be selected.
- Drill a 50 mm diameter hole in the pipe and prepare to weld the pipe to the hole. Insertion electromagnetic flowmeters are easy to install and can continuously measure flow. A pressure tap is available on-site. This offers significant installation and price advantages.
- Flow measurement is dependent solely on insertion depth, making this flowmeter highly versatile and interchangeable. One model can meet the fluid measurement needs of various pipe sizes.
Precautions
Do not use a lifting rod or rope to pass through the flowmeter measurement pipe. This will damage the inner wall of the measuring pipe and render the flowmeter useless.
For flowmeters larger than DN80, do not support the flowmeter's converter or junction box by hand or with rope. Because the converter or junction box is made of a relatively brittle aluminum alloy, it cannot withstand significant weight. Care must be taken to protect the flow sensor's lining during storage, transportation, and installation to prevent damage.
Insertion-Type Electromagnetic Flowmeter
Omega's insertion flowmeters feature standard 2 NPT connections or can be fitted with custom-sized connectors. The FMG-550 series is designed for pipes from 2 to 48 inches and has a flow rate range of 0.05 to 10 m/s (0.15 to 33 ft/s). The FMG-550 Series offers an analog output and a built-in display showing flow rate and totalizer values. The FMG3000 Series utilizes corrosion-resistant materials and is suitable for pipe sizes from 0.5 to 8 inches. These insertion flow meters are ideal for larger pipe applications.
Minimum Conductivity
5 to 200 microsiemens/cm
Installation Considerations
Select a sensor installation location where the flow profile is well-developed and free from interference. A straight pipe run of at least 10 pipe diameters upstream and 5 pipe diameters downstream is recommended. In some cases, a straight pipe run of at least 20 pipe diameters or more upstream may be required to ensure a well-developed turbulence profile. Insertion electromagnetic flow meters are sensitive to air bubbles at the electrodes. If the pipe is suspected to be completely full, install the sensor between 45 and 135 degrees.
Grounding Requirements
For many years, sensors used in high-reliability applications such as aerospace and military relied on connectors such as MIL-C-5015 or MIL-C-38999. While these connectors offer high reliability and secure connections, they are expensive. However, with the widespread adoption of industrial automation systems, the number of sensors has increased dramatically, necessitating a reliable and cost-effective sensor connection system.
Inline Electromagnetic Flowmeters
In-line electromagnetic flowmeters offer higher accuracy, reaching up to 0.5% of the flow rate. Insertion-type flowmeters offer an accuracy of 0.5% to 1%. OMEGA's FMG-600 series of in-line flange and wafer-type flowmeters offer higher flow rates from 1 to 10 m/s. These in-line flowmeters support pipe sizes up to 12 inches.
Installation Considerations
In-line flowmeters do not require as much straight pipe length as insertion flowmeters. It is recommended to maintain a straight pipe run of at least 5 to 10 pipe diameters upstream and 1 to 2 pipe diameters downstream. In vertical pipes, fluid should always flow upward, not downward. This type of flowmeter is very sensitive to air bubbles. Electromagnetic flowmeters cannot distinguish between entrained air in the process fluid; therefore, air bubbles can cause electromagnetic flowmeter readings to be falsely high. Low-Flow Magnetic Flowmeters These low-flow magnetic flowmeters also feature an in-line design and are available with 3/8 to 1/2 NPT connections. The FMG200 series can provide flow rates as low as 0.38 LPM (0.1 GPM). A digital display with relay and analog outputs is standard.
