(Called as sounding pipe) which opens at the tank bottom. When a light quantity of air (supplied from flow
Regulator) is discharged through the purge mouth at the tank bottom. An air pressure corresponding to
The liquid level will be built up in the sounding pipe.
If the specific gravity of the liquid is known and a pressure in the sounding pipe is measured, it is
Possible to calculate the distance from the pipe opening to the surface by means of the above
Expression. The pressure is read on the indicator graduated scale in meters or volume or percent of full
Tank.