Flow Measurement in Line.
We need to measure flow in a particular line in Industry even in our house water pipe line. But how will we measure? Recently I have discussed about the role of instrumentation in various industries. There I have pointed out about various parameters measurement. Here I want to discuss about flow measurement. The flow may be gas or water or air in the line.
Equipments required:-
- One Transmitter
- One Digital Indicator
- One controller
- One control Valve
- One power supply unit (24V )
- One orifice (fitted in the line)
- Two coiled wire (as per requirement)
- Mild steel ½” impulse line ( as per requirement)
Here is a hand made drawing done to understand -
First look carefully to the picture and have a look where the equipments fitted. Two lines, one is called high pressure line and which should be connected with that side from where flow is coming. Another side is called low pressure side and is connected with other side as shown in the picture.
Thus differential pressure is created and the transmitter responds. Suppose differential range is 0-10000 nm3 and the Transmitter range is 4-20 mA, then
In 0 flow the transmitter will give an output 4 mA i.e. now no flow in line.
Similarly In 10000 differential flow the transmitter will give 20mA i.e. maximum flow and maximum output. This current will vary according to flow of that line. We can receive the output in voltage also. This output goes to a digital indicator which shows the visual reading.
One output goes to a controller and which control a valve .Valve takes current as input and through an I/P converter it gives the measurement that how much the valve will open or close.
This is called Auto system. The control program is done in controller and a set value is given to that. Set value depends upon manufacturers demand.
Thus a flow measurement is done. If it helps to any then this discussion will be fruitful.