This project began with a phone call at 4 a.m. from the water treatment plant operator letting me know that water was gushing out of our pilot trailer. A pipe on the effluent side of the filter had burst and started leaking. What made it worse was the fact that the system was running under constant-flow mode. So the motor was running at full-speed trying to bring the flow back up to the set-point flow rate. Luckily, aside from the mess, the damage was minimal. However, we weren't willing to risk damaging expensive equipment with another inevitable incident. I started researching the web for a solution that could prevent this from happening in the future. I had two criteria in mind, 1) detect and report a leak incident and 2) shut the system off during a leak. Unfortunately, I couldn't find a simple and cheap solution that could do both and so I decided to try and create a solution myself. I took a trip to our local Home Depot and browsed around their alarms aisle. I found this relatively inexpensive battery operated water alarm.
The alarm has a loud speaker that gets triggered when the sensors come into contact with water. My idea was to simply remove the speaker and connect the leads to the DAQ (data acquisition device) that measures +/-10V to see if that signal could be used. The solution was relatively easy to implement and has helped prevent some major disasters!!
Leak Detector Modification
The alarm outputs a voltage of approximately 8V. The signal can be incorporated into a program like LabView in oder to trigger a sequence of events during a leak.
Application Example: Triggering Pumps/Valve
The leak signal was incorporated into a series of If-Then statements that control the pumps. When the voltage from the leak alarm passes a threshold voltage (6V), the pumps stop and a series of actuated valves switch to the close position.
Application Example: Leak Notification
If the computer has access to the Internet, the LabView program below can be used to send email and text notifications in the event a of leak.
The example LabView program can be downloaded here
Application Example: Water Level Sensor
The sensor can also be used as a water level sensor to trigger pumps and/or valves when the water reaches a certain level.