We all know flowmeters and obviously, it is used to measure the flow of fluid, liquid, or gas. Magmeter is no different it is a type of flowmeter, which is used to measure the volumetric flowrate and they are also called as Magnetic flowmeters.
Its works on the principle of the faradays law of electromagnetic induction. So it can be used only for the liquids which are conductive in nature and the conductivity of the liquid should be at least a minimum of 5 microsiemens per second.
Faraday's law states, Whenever a conductor of length 'l' with velocity 'v' moves perpendicular to the magnetic field 'B' an emf is generated in the mutually perpendicular direction.
E = Blv
where E is emf.
v = E/Bl
The volume flow rate Q is given by,
Q = Av
Hence volumetric flow is directly proportional to EMF induced. K is a constant here.
The magnetic flowmeter consists of wired coils mounted on the body of the flowmeter to generate a magnetic field and Two electrodes placed opposite to each other and perpendicular to the magnetic field to detect and measure the induced emf ( voltage ) and the two electrodes are connected to the electronic circuit to convert the induced voltage into volumetric flowrate which is directly proportional to the induced emf.
When a liquid that acts as a conductor flows through a magnetic field an emf ( voltage ) is generated as per faraday’s law and the two electrodes which are placed in contact with the flowing fluid measure the induced emf. The induced emf is directly proportional to the volumetric flow rate.
Grounding is very important for accurate and reliable measurements and to reduces the electrical noise