Working principle of different types of flowmeters
There are different types of flowmeters according to their principles which are listed below.
(1) Mass flow meter
(2) Magnetic flow meter
(3) Vortex flow meter
(4) Thermal mass flowmeter
This flowmeters are often used in the chemical industries,petrochemical industries,refinery etc.
Now,Brifely explain the principle of different types of flowmeter.
(1) Mass flow meter
Mass flow meter works on "Coriolis principle" which is states that it contains a vibrating tube in which a flowing fluid causes changes in frequency,phase,shift and amplitude.
The output is carried out on pc-board and the output is directly proportional to the mass flow rate.
This flowmeter is most accurate and reliable.
This flowmeter consist a two tube and when the fluid flow in this tube,it is oscillate symmetrically and sensor sense a signal and the result produced in the form of sinewave.
As shown in fig,there is a three parts,(1) Pick up 1 (2) Pick up 2 (3) Driver.
The driver coil which drives a tubes,the pick up 1 and pick up 2 is a sensor which sense the flow of fluid.
When pick up 1 and pick up 2 sense the flow it generates a sinewaves and the time difference of phase shift between two sinewave is equal to the mass flow rate.
(2) Magnetic flowmeter
Magnetic flowmeter works on the principle of "Faraday's law of electromagnetic induction".
It's internal construction consist two electrodes.
When electrically conductive fluid is pass through pipe,an electrode voltage E is induced between a pair of electrodes.
So,this induced voltage is proportion to the flow velocity in the pipeline.
(3) Vortex flowmeter
Vortex flowmeter works on the principle of "Karman effect".
It consist a "bluff body" in the pipe of flowmeter. When the flow is flow trough pipe,the flow is continuously generates a vortices.
The generation of vortices is called a karman vortices.
Then flowrate is calculated by multiplying the area of the pipe times the velocity of the flow.
(4) Thermal mass flowmeter
Thermal mass flowmeter works on the principle of the "thermal dispersion".
When the fluid is flow through pipe,the heat is absorbed by a fluid and which is directly proportional to its mass flow.
As a gas flow increase more heat is absorbed by the gas.
The heat is dissipated from the heated probe is proportional to the mass flow rate.
This flowmeter is used in gas application.
The driver coil which drives a tubes,the pick up 1 and pick up 2 is a sensor which sense the flow of fluid.
When pick up 1 and pick up 2 sense the flow it generates a sinewaves and the time difference of phase shift between two sinewave is equal to the mass flow rate.
(2) Magnetic flowmeter
Magnetic flowmeter works on the principle of "Faraday's law of electromagnetic induction".
It's internal construction consist two electrodes.
When electrically conductive fluid is pass through pipe,an electrode voltage E is induced between a pair of electrodes.
So,this induced voltage is proportion to the flow velocity in the pipeline.
(3) Vortex flowmeter
Vortex flowmeter works on the principle of "Karman effect".
It consist a "bluff body" in the pipe of flowmeter. When the flow is flow trough pipe,the flow is continuously generates a vortices.
The generation of vortices is called a karman vortices.
Then flowrate is calculated by multiplying the area of the pipe times the velocity of the flow.
(4) Thermal mass flowmeter
Thermal mass flowmeter works on the principle of the "thermal dispersion".
When the fluid is flow through pipe,the heat is absorbed by a fluid and which is directly proportional to its mass flow.
As a gas flow increase more heat is absorbed by the gas.
The heat is dissipated from the heated probe is proportional to the mass flow rate.
This flowmeter is used in gas application.
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