Electromagnetic Flow Meter
What is Precision Flow Measurement Technology?
The electromagnetic flow meter is a device used for measuring the flow of the liquid when it passes through the pipeline. Or we can say that the electromagnetic flowmeter uses for measuring the flow rate of the electrically conducting fluid. The electrically conductive liquid means the liquid allows the current to pass through it. The electromagnetic flowmeters work on the principle that the obstruction is created in the path of the liquid and the pressure of the liquid induces the voltage across the coil.
Working Principle of Electromagnetic Flowmeter
The electromagnetic flowmeter works on the principle of Faraday’s Law of electromagnetic induction. This law states that when the conductive liquid passes through the magnetic field, the voltage induces across the conductor. The magnitude of the voltage is directly proportional to the velocity, length of the conductor and the strength of the magnetic field. The magnetic field is generated by the coil which is mounted on the external metallic body of the pipe. The liquid acts as a conductor and when passes through the magnetic field induce the voltage across the coil. The magnitude of the voltage depends on the velocity of the liquid.
Construction of Electromagnetic Flowmeter
The electromagnetic flow meter consists of the electrically insulated pipe made of fibre. Electrodes placed opposite to each other; magnetic coil placed on the pipe for generating the magnetic field etc. The insulated pipe carries the liquid whose flow needs to be measured. The electromagnet is placed around the insulated pipe. This electromagnet induces the magnetic field around the pipe. The arrangement is similar to the conductor moving in the magnetic field. The voltage is induced across the coil because of the flow of the liquid. The induces voltage is expressed as, If the magnetic field around the pipe remains constant than the generating voltage is proportional to the velocity of the fluid.
Where, v – velocity of conductor (flow); m/s
l – length of conductor = diameter of pipe; m
B = flux X density; wb/m2
- E = Induced voltage
- K = Constant
- B = Magnetic field strength,
- D = Distance between electrodes,
- V = Liquid flow velocity
Types of Electromagnetic Flowmeter
Insertion
Is a type of magmeter with a shape resembling a headed stick whose installation is perpendicular to the flow of liquid. Unlike standard magnetic flow meters, the magnetic field in this magmeter is formed from a magnet in the stick. This type is very suitable for pipes with a wide cross-sectional area.
In-line
Is a type of standard magmeter that has an inline pipe location (in line) with the direction of flow. The location of the components is as described above. This type is more suitable for pipes with a small-medium cross-sectional area and requires higher accuracy.