What is an Electromagnetic flowmeter?
An electromagnetic flowmeter is a type of flow meter used to measure the flow rate of conductive fluids, such as water or other liquids. It operates based on Faraday’s law of electromagnetic induction, where a magnetic field is applied to the fluid, and the voltage induced across the fluid’s velocity is measured. This voltage is directly proportional to the fluid’s velocity, enabling the flowmeter to accurately determine the flow rate. Electromagnetic flowmeters are commonly used in various industrial and water management applications.
How to Calibrate an Electromagnetic Flow Meter?
Purpose and Scope:
This procedure’s detailed description explains how to calibrate a An electromagnetic flowmeter (transmitter) using a standard portable reference flow meter in the process area or flow calibration lab.
Tools required for Electromagnetic Flow Meter calibration:
- Necessary hand tools.
- Standard reference flow meter
- Test leads and probes.
- Soft Cloth for cleaning.
- Check out the following link to learn more about process industry safety basics, general advice, and calibration operations.
- Ask the panel operator to set up the controller in manual mode for the control loop of the electromagnetic flow meter and MOS for the ESD loop.
- Look for an Electromagnetic flow transmitter that needs to be calibrated. Make sure the magnetic flow transmitter you are working with is the appropriate one, and note and double-check any important details, such as the Tag number (which may include the manufacturer, model number, flow range, etc.).
- Observe all safety guidelines set established by your company, particularly those that involve the use of personal protective equipment (PPE) such as gloves, safety glasses, and appropriate attire.
- Make sure the process is in proper working order before calibrating the electromagnetic flow meter to prevent any potential hazards, such as leaks, spills, or exposure to hazardous compounds.
- Verify the power source for the electromagnetic flow meter. Check any nearby junction boxes or marshalling panels close to the control room to see if the power supply is present at the source using an instrument loop diagram for the vortex flow meter.
- If you want to remove the electromagnetic flow meter to clean the flowtube, de-energize it and disconnect it from any power sources or process fluids using lockout/tagout procedures. This method is essential for protecting workers against the unexpected release or energization of stored energy.
- If the calibration involves working with potentially hazardous substances, ensure proper ventilation in the area to prevent the buildup of fumes or gases.
- Use calibrated and appropriate tools and equipment for calibration. Ensure that all instruments are in good working condition and comply with safety standards.
- Ensure that cables and wires are properly secured and not exposed to potential damage or tripping hazards.
- Perform a risk assessment of the calibration procedure, identifying potential hazards and implementing appropriate control measures to minimize risks.
- Comply with all local safety regulations, guidelines, and permits relevant to the calibration process.
- Adhere to the standard operating procedures (SOPs) provided by the manufacturer for calibration. Familiarize yourself with the specific steps and safety guidelines mentioned in the calibration manual.
Calibration Setup for Electromagnetic flow meter
- Install the standard Ultrasonic portable reference flow meter in the same pipeline or a parallel line with the electromagnetic flow meter in the process pipe.
- Ensure that both flow meters are securely mounted and aligned with the flow path to ensure accurate measurements.
- Follow the reference flowmeter manufacturer’s guidelines for proper installation, including any necessary alignment and mounting procedures.
- Connect the necessary transducer coaxial cables between ultrasonic probes and the reference flowmeter and also prepare power connection for the ultrasonic flow meter.
- Identify the pipeline material where the electromagnetic and Ultrasonic reference flow meters are installed. For calibration accuracy, pipe material might alter flow velocity profile. Details of the pipe material must be configured in the reference flowmeter.
- Determine the density and conductivity of the process liquid. Knowing their characteristics aids in selecting calibration settings for reference flowmeter.
- Verify the reference Ultrasonic flow meter’s frequency range and settings. Based on the anticipated flow rate and the pipe size, choose an appropriate frequency.
- Consider the thickness of the pipeline wall when determining the signal penetration of the ultrasonic flow meter. In order to ensure accurate results, ultrasonic flow meters require a sufficient path thickness. If there is any paint on the pipeline where the ultrasonic probes will be installed, remove it. Additionally, the reference flowmeter must be configured with the measured pipe thickness.
- Understand the path configuration of the Ultrasonic flow meter (e.g., single-path, dual-path, or clamp-on). This can affect measurement accuracy, especially in non-full pipe conditions.
- Prepare the calibration equipment and multimeter in series with a panel to measure the mA current.
- To measure the mA current, set up the calibration equipment and multimeter in series with an electromagnetic flowmeter.
- Verify that the flow channels for both the electromagnetic flowmeter that is being tested and the standard reference flow meter are unobstructed and unrestricted.
- Make that the pipes, connectors, and valves are properly installed, attached, and functioning.
- Create the documentation for the electromagnetic flowmeter calibration that is required, including calibration sheets, data recording forms, and any other particular forms or templates that your business may require.
- Make sure you have all the necessary information and specifics, including flow rates, measurements, and any modifications done, to accurately record the calibration procedure.
- The standard flow meter’s functioning, stability, and accuracy should all be verified as part of pre-calibration tests that should be performed as needed.
- As shown in the diagram, the connections have been made and are currently being ready for the calibration of the electromagnetic flowmeter.
Calibration procedure of electromagnetic flowmeter
- Make that the process area is appropriately set up including the installation and connection of the electromagnetic flowmeter and the standard reference flow meter.
- Verify the accuracy and calibration of the standard reference ultrasonic flow meter using a valid certificate.
- By making sure that no liquid is moving through the pipeline but that the liner is filled with process liquid, you can open the process input valve and set both flow meters to zero flow conditions.
- Check that both meters give similar readings at zero flow. To align the readings from the two devices at zero flow, adjust the zero offset on each device as necessary.
- Determine the desired calibration points that cover the expected flow range of the electromagnetic flowmeter. These points should be evenly spaced across the flow range and should include low, medium, and high flow rates.
- With the outlet valve partially throttled to reduce the flow, set the electromagnetic flowmeter to the first calibration point.
- Simultaneously, record the flow rate measurements from both the electromagnetic flowmeter and the reference Ultrasonic Flow Meter at each calibration point with the outlet valve throttled.
- Compare the flow rate measurements from the electromagnetic flowmeter with the corresponding measurements from the reference Ultrasonic Flow Meter at each calibration point with the outlet valve throttled.
- Take note of any differences between the readings, considering the effect of the throttled flow conditions.
- If there are significant differences between the measurements, adjust the calibration factors on the electromagnetic flowmeter to minimize the discrepancies while accounting for the throttling conditions.
- This may involve applying correction factors or adjusting the meter’s settings to improve its accuracy under throttled flow.
- Consult the electromagnetic flowmeter manufacturer’s documentation or guidelines for specific instructions on adjusting the calibration settings.
- Repeat the adjustments and measurements as necessary until the readings align closely
- Adjustments and measurements should be repeated as needed until the readings are almost identical.
- By throtilling the output valve, you can adjust the flow rate to different levels within the desired range.
- At each flow rate, take measurements with the electromagnetic flowmeter and the standard reference flow meter at the same time.
- In addition, while calibrating the electromagnetic flowmeter, compare its equivalent mA output with a multimeter.
- Compare the readings from both meters, as well as the mA output from the electromagnetic flowmeter, to determine the accuracy and consistency of the electromagnetic flowmeter.
- Repeat the measurements and comparisons at different flow rates within the desired range of electromagnetic flowmeter in upscale and downscale.
- Verify that the readings of the electromagnetic flowmeter closely match those of the standard reference flow meter, indicating successful calibration.
- Confirm the accuracy and repeatability of the electromagnetic flowmeter across the calibrated range.
- If the output value of the electromagnetic flowmeter does not fall within an acceptable range, calibration is required. The electromagnetic flowmeter needs to be repaired or replaced if the output readings have once again fallen outside of the permissible range.
- If all output values (+/-%) fall within acceptable bounds, then the electromagnetic flowmeter does not require any further calibration.
- The output data should be entered in the as found/as left column of the blank electromagnetic flowmeter calibration report.
Completion of calibration
- Once the calibration has been successfully conducted, attach the calibration label to the electromagnetic flowmeter.
- Disconnect the calibration setup and reference flow meter.
- Clean and store the electromagnetic flowmeter calibration test equipment after calibration. Record the electromagnetic flowmeter calibration data for future use.
- In the processing area, the electromagnetic flowmeter connections must be restored.
- Check the workspace of the electromagnetic flowmeter for cleanliness.
- De-isolate the equipment. After the electromagnetic flowmeter has been installed and de-isolated, it is important to inspect the pipe for any signs of a leak.
- Restore the bypassed or suppressed signal of the electromagnetic flowmeter to its original level.
- Make sure the electromagnetic flowmeter is functioning properly before using it.
Sample calibration report
The image that follows shows how the electromagnetic flowmeter sample report was calibrated in a process area utilizing a reference standard ultrasonic flow meter and multimeter as the reference.
You may get the Excel document that was used to construct the electromagnetic flowmeter calibration report by clicking the link below.