Bubbler Systems for Liquid Level Measurement
These systems have no moving parts, which makes them a reliable and robust solution.
The technology has been tried and true for many years and is an economical solution for a variety of environments.
The bubbler system works by forcing a gas (compressed air) at a near constant flow rate out the bottom of an open tube (bubble/dip tube) submerged in liquid. The back pressure in this tube is measured. With the process liquid’s density known, the level can be calculated using the back pressure and density. A pressure transmitter converts the back pressure to provide a 4-20ma output to a controller, which calculates the liquid’s level.
As the liquid level increases, the head pressure on the bubble tube gets higher. This means more pressure is needed to maintain a constant flow rate to overcome the pressure of the fluid.
If the fluid level goes down, so does the head pressure on the bubble tube and the pressure required to maintain constant flow rate of air or gas.
To minimize maintenance requirements, we can add a purge line to clear the bubble tube of debris and buildup. This can be a manual operation with the push of a button, or automated with a purge schedule and timer.