Question

What kind of methods used to measure the liquid level explain in detail?

Answer 1

There are generally two different methods of measuring the liquid level they are:-

1.) Direct method:-

In this method liquid's level are directly measured on the scale. The means of level measurement in direct method are the variation in the liquid's level. Direct method are again sub divided into different measuring method that are:-

a.) Based on direct visual observation:-

• Gauge stick
• Hook gauge
• Gauge glass

b.) Based on buoyancy method:-

• Float gauge
• Displacer gauge

2.) Indirect method:-

In indirect method level is measured in terms of variable such as hydrostatic pressure, attenuation of radioactive energy, electrical properties e.t.c which changes with change in liquid's level. Indirect method are again sub divided into different measuring methods that are:-

a.)based on hydrostatic head developed by the liquid:-

• Pressure gauge method
• Air trip method
• Diaphragm box method
• Air purge or bubbler method
• Differential pressure method

b.) electrical capacitance method

c.) Radiation method.

As it's a bit difficult to explain every method so we will go for the most important and widely used method i.e. hydrostatic head based measurement method.

For this we use a pressure transmitter in order to determine the liquid level in any kind of container i.e it can be well, tank, river etc. In this method we make use of the pressure at the bottom of the liquid filled container which is directly related to the height of the liquid. So the pressure transmitter measures the hydrostatic head pressure and gives the resulting liquid level of the liquid within any container.