it principle denpend on what kind of flow meter. example, magnetic flow meter, it use magnetic force to measuring or coriolis flow meter which is use vibrated capilary tube as sensor. or more info you might watch on youtube.
it works on the electromagnetic principle the conductor cuts the magnetic field which produces induces emf for the flow of current
One of the easiest ways to detect a magnetic field is with a length of conductive material attached to a voltage meter. The presence of a magnetic field causes an electrical current to flow through the conductor, thus causing a spike on the meter.
the basic principle on which a Venturimeter works is that by reducing the cross-sectional area of the flow passage, a pressure difference is created and by measuring this pressure difference, discharge through the pipe can be determined. formula to find actual discharge is=amount of fluid collected/time taken it works on the principle of bernoulli"s equation
The basic principle of the pressure tube log is to measure the pressure difference between two points along a tube to calculate fluid flow rate. By measuring the pressure at these points and knowing the fluid characteristics, the flow rate can be determined using a formula based on Bernoulli's principle.
An electromagnetic flow meter is a flowmeter which uses the electromagnetic technology to determine the amount of volume flow though a pipe. View the Related Links section for a link with a video about this.
A Venturi meter works based on the principle of Bernoulli's equation, which states that an increase in fluid velocity results in a decrease in pressure. The Venturi meter is a device that measures the flow rate of a fluid by creating a pressure difference between two points in a pipe, allowing for flow rate calculations based on this pressure difference.
THE SYMBOL FOR Flow Meter is : FI as Flow Indicator
The above is the symbol of flow meter.
A DC clamp meter works by measuring the magnetic field produced by the flow of direct current in a conductor. When the clamp is placed around the conductor, it detects the magnetic field and converts it into a direct current measurement. This measurement is then displayed on the meter's screen.
One can recalibrate a flow meter by having a company or owning a flow meter supplier or using a flow meter lab. No matter what type of flow meter they need to be checked to see if they need to be recalibrated regularly.
A clamp on amp meter is used for this purpose. When amperage is present in a wire there will be a magnetic field generated around the wire. The clamp on amp meter measures this magnetic field and converts it to an amperage value that is read on the screen of the amp meter. No current flow, no magnetic field, no reading. A dangerous and non recommended way to check current flow is to open the circuit when the load is connected and operating. There will be a small arc that jumps across the gap when the circuit is opened. This is current flowing in the circuit.