Emerson Rosemount 2051 Reference Manual page 46

Hardware Installation
November 2016
Bubbler system in open vessel
A bubbler system that has a top-mounted pressure transmitter can be used in open vessels.
This system consists of an air supply, pressure regulator, constant flow meter, pressure
transmitter, and a tube that extends down into the vessel.
Bubble air through the tube at a constant flow rate. The pressure required to maintain flow
equals the liquid's specific gravity multiplied by the vertical height of the liquid above the
tube opening.
Figure 3-14. Bubbler Liquid Level Measurement Example
Let X equal the vertical distance between the minimum and maximum measurable levels (100-in.).
Let SG equal the specific gravity of the fluid (1.1).
Let h equal the maximum head pressure to be measured in inches of water.
Let Range equal zero to h.
Then h = (X)(SG)
Range = 0 to 110 inH
H
i
Range
36
Figure 3-14 shows a bubbler liquid level measurement example.
= 100 1.1
= 110 inH O
2
O
2
0
inH
2
Air
T
X
L
o
110
O
Reference Manual
00809-0300-4101, Rev BB
Hardware Installation