What is ISO 20456 — Electromagnetic flowmeters for conductive liquids about?
ISO 20456 is an international standard that focuses on electromagnetic flowmeters for conductive liquids. ISO 20456 applies to industrial electromagnetic flowmeters used for the measurement of the flow rate of a conductive liquid in a closed conduit running full.
ISO 20456 covers flowmeter types utilizing both alternating current (AC) and pulsed direct current (DC) circuits to drive the field coils and meters running from a mains power supply and those operating from batteries or other sources of power.
Note 1: ISO 20456 does not cover insertion type meters, partially filled meters, or meters for non-conductive and highly conductive fluids.
Note 2: ISO 20456 is not applicable to insertion-type flowmeters or electromagnetic flowmeters designed to work in open channels or pipes running partially full, nor does it apply to the measurement of magnetically permeable slurries or liquid metal applications.
Note 3: ISO 20456 is not applicable to insertion-type flowmeters or electromagnetic flowmeters designed to work in open channels or pipes running partially full, nor does it apply to the measurement of magnetically permeable slurries or liquid metal applications.
Note 4: ISO 20456 does not specify safety requirements in relation to hazardous environmental usage of the flowmeter.
Who is ISO 20456 — Electromagnetic flowmeters for conductive liquids for?
ISO 20456 on electromagnetic flowmeters for conductive liquids is relevant to:
- Manufacturers of electromagnetic flowmeters
- Electromagnetic engineers
- Chemical engineers
- Testing establishments
Why should you use ISO 20456 — Electromagnetic flowmeters for conductive liquids?
An electromagnetic flowmeter is a flowmeter, that creates a magnetic field perpendicular to the direction of flow, so enabling the flowrate to be deduced from the induced voltage, Uv, produced by the motion of a conducting fluid through the magnetic field Electromagnetic flowmeters are based on the laws of electromagnetic induction.
ISO 20456 stipulates the technicalities such as the installation types and practice, the different types of meter construction, transmitters, lay lengths, and sizes, for the electromagnetic flowmeters for conductive liquids, in order to achieve the best performance of the electromagnetic flowmeter in the field. ISO 20456 describes some methods of calibration, verification, evaluation, and uncertainty analysis, which can be useful for users or independent testing establishments to verify the manufacturer’s relative performance and to demonstrate the suitability of the application.
Overall, ISO 20456 is useful as it provides guidance on the special precautions that are necessary to ensure that the direct current component of the cathode current does not affect the accuracy and stability of the flowmeter system.