Leak detection in water distribution systems using acoustic signals

Abstract

Examples of a leak detection system are disclosed. In one example according to aspects of the present disclosure, a leak detection system includes a housing defining an interior, the housing connected to a component of a water distribution system. The leak detection system also includes a leak detection sensor contained within the interior of the housing and configured to detect a leak within the water distribution system. Additionally, the leak detection system includes a digital signal processing circuit in communication with the leak detection sensor.

1 - 20 . (canceled) 
     
     
         21 . A method comprising the steps of:
 periodically waking from a sleep state by a leak detection device attached to a fire hydrant of a water distribution system;   determining, by the leak detection device, whether a current time is a scheduled data recording time, wherein the scheduled data recording time is provided to the leak detection device by a host system;   upon determining that the current time is the scheduled data recording time, recording, by the leak detection device, sensor data from at least one acoustic sensor attached to the fire hydrant;   processing, by the leak detection device, the sensor data; and   storing, by the leak detection device, the recorded sensor data in a memory of the leak detection device.   
     
     
         22 . The method of claim  1 , wherein the recording and processing of the sensor data is performed by a digital signal processing circuit of the leak detection device. 
     
     
         23 . The method of claim  1 , wherein the processing of the sensor data comprises compressing the sensor data before storing the sensor data in the memory. 
     
     
         24 . The method of claim  1 , wherein the leak detection device is periodically woken from the sleep state by a real-time clock circuit in the leak detection device. 
     
     
         25 . The method of claim  1 , further comprising the steps of:
 determining, by the leak detection device, whether the current time is a scheduled leak detection time;   upon determining that the current time is the scheduled leak detection time, reading, by the leak detection device, sensor data from the at least one acoustic sensor; and   determining, by the leak detection device, a probability of a leak in the water distribution system based on the read sensor data.   
     
     
         26 . The method of claim  5 , wherein determining the probability of a leak in the water distribution system comprises comparing an acoustic signal in the read sensor data to a baseline waveform recorded by the leak detection device and stored in the memory. 
     
     
         27 . The method of claim  6 , wherein determining the probability of a leak in the water distribution system further comprises performing a fast Fourier transformation of the acoustic signal and comparing the transformed acoustic signal with the baseline waveform in a predetermined frequency bandwidth. 
     
     
         28 . The method of claim  1 , further comprising the steps of:
 waking, by the host system, the leak detecting device from the sleep state;   receiving, by the leak detection device, data from the host system, the received data comprising at least the scheduled data recording time; and   sending, by the leak detection device, data to the host system, the sent data comprising at least the recorded sensor data stored in the memory.   
     
     
         29 . The method of claim  8 , wherein the received data further comprises one or more of a length of data to record, a sampling frequency, an analog-to-digital resolution, and frequency data to be utilized by a digital signal processor of the leak detection system in recording and processing the sensor data. 
     
     
         30 . The method of claim  8 , wherein the host system wakes the leak detection device by sending a transmission to an RF circuit of the leak detection device. 
     
     
         31 . The method of claim  8 , wherein the host system uses sent data and data received from a leak detection device in an adjacent fire hydrant in the water system to determine a general location of a potential leak. 
     
     
         32 . The method of claim  1 , wherein the leak detection device and the at least one acoustic sensor are integrated into a nozzle cap of the fire hydrant. 
     
     
         33 . A leak detection apparatus comprising:
 a sensor assembly comprising at least one sensor configured to sense acoustic signals in pipes of a water distribution system;   a microcontroller unit (“MCU”) communicatively connected to the sensor assembly and configured to receive the acoustic signals from the at least one sensor;   a memory operably communicatively connected to the MCU and configured to store leak detection data;   a digital signal processor (“DSP”) communicatively connected to the MCU and configured to process the acoustic signals from the at least one sensor;   a communication device communicatively connected to the MCU and configured to communicate the leak detection data between the leak detection apparatus and a host system; and   a real-time clock circuit (“RTC”) operatively connected to the MCU, the leak detection apparatus configured to
 periodically wake up, 
 determine whether a current time from the RTC is a scheduled data recording time, the scheduled data recording time provided to the leak detection apparatus by the host system, 
 upon determining that the current time is the scheduled data recording time, record the acoustic signals from the sensor assembly at the MCU, 
 process the recorded acoustic signals in the DSP, 
 store the processed recorded acoustic signals in the memory, 
 receive a transmission from the host system in the communication device, and 
 upon receiving the transmission from the host system, send the stored acoustic signals in the memory to the host system through the communication device. 
   
     
     
         34 . The leak detection apparatus of claim  13 , wherein the processing of the acoustic signals in the DSP comprises compressing the acoustic signals before storing in the memory. 
     
     
         35 . The leak detection apparatus of claim  13 , wherein the leak detection apparatus is further configured to:
 determine whether the current time from the RTC is a scheduled leak detection time, the scheduled leak detection time provided to the leak detection apparatus by the host system;   upon determining that the current time is the scheduled leak detection time, read the acoustic signals from the sensor assembly;   process the read acoustic signals in the DSP; and   determine a probability of a leak in the water distribution system based on the processed read acoustic signals.   
     
     
         36 . The leak detection apparatus of claim  15 , wherein determining the probability of a leak in the water distribution system comprises comparing the acoustic signals read from the sensor assembly to a baseline waveform recorded by the leak detection apparatus and stored in the memory. 
     
     
         37 . The leak detection apparatus of claim  16 , wherein determining the probability of a leak in the water distribution system further comprises performing a fast Fourier transformation of the acoustic signal and comparing the transformed acoustic signal with the baseline waveform in a predetermined frequency bandwidth. 
     
     
         38 . The leak detection apparatus of claim  16 , wherein the leak detection apparatus is integrated into a nozzle cap of a fire hydrant of the water distribution system. 
     
     
         39 . A system for detecting leaks in a water distribution system, the system comprising:
 a host system;   a sensor assembly comprising at least one sensor configured to sense acoustic signals in pipes of the water distribution system; and   a leak detection device communicatively connected to the sensor assembly and the host system, the leak detection device configured to
 receive a scheduled data recording time from the host system, 
 periodically wake from a sleep state, 
 determine whether a current time is the scheduled data recording time, 
 upon determining that the current time is the scheduled data recording time, record the acoustic signals from the sensor assembly, 
 compress the recorded acoustic signals, 
 store the compressed acoustic signals in a memory of the leak detection device, 
 received a transmission from the host system, and 
 upon receiving the transmission from the host system, send the stored acoustic signals to the host system; 
   wherein the leak detection device and the sensor assembly are attached to a fire hydrant of the water distribution system.   
     
     
         40 . The system of claim  19 , wherein the host system uses acoustic signals sent by the leak detection device and acoustic signals received from a leak detection device in an adjacent fire hydrant in the water system to determine a general location of a potential leak.