Detecting leaks in pipes

Abstract

An apparatus for permanently or semi-permanently fitting to an underground water pipe 15,16 for detecting leaks therein, comprises a hydrophone 26 mounted to acoustically monitor water flowing along the pipe 15,16 and means 29 for analysing a parameter of the output signal of the hydrophone 26 and for generating an alarm signal, in the event that the parameter is above a maximum value or below a minimum value. The apparatus further comprises a radio transmitter for transmitting the alarm signal to a remote receiver, so as to indicate the detection of a leak. The maximum and minimum values are preferably calculated using historical data obtained from the hydrophone 26, so that the values are automatically adjusted to suit location of the apparatus. In use, a plurality of leak detection apparatus can be installed to pipes at various locations around a geographical area of supply. Once a leak has been identified in an area, it is then a relatively simple matter to more precisely determine where in the area should be surveyed using a conventional leak detector. Thus, the need to survey the whole of the area using a conventional leak detector is avoided.

1 . An apparatus for detecting leaks in pipes comprising a transducer for acoustically monitoring the pipe, means for analysing a parameter of the output signal of the transducer and for generating an alarm signal, in the event that the parameter is above a maximum value or below a minimum value and means for outputting said alarm signal.  
   
   
       2 . An apparatus as claimed in  claim 1 , in which the alarm signal output means comprises an optical or audible transducer.  
   
   
       3 . An apparatus as claimed in  claim 1 , in which the alarm signal output means may is arranged to transmit the alarm signal along a cable to a remote receiver.  
   
   
       4 . An apparatus as claimed in  claim 1 , in which the alarm signal output means comprises a transmitter, which transmits a wireless alarm signal. to a remote receiver.  
   
   
       5 . An apparatus as claimed in  claim 4 , in which the transmitter transmits a low power radio signal.  
   
   
       6 . An apparatus as claimed in  claim 4 , in which the transmitter is arranged to transmit a standby signal when said parameter is not above said maximum value or below said minimum value.  
   
   
       7 . An apparatus as claimed in  claim 4 , in which the transmitter transmits a signal periodically.  
   
   
       8 . An apparatus as claimed in  claim 6 , in which the transmitter transmits a signal periodically, the alarm signal being transmitted more frequently than the standby signal.  
   
   
       9 . An apparatus as claimed in  claim 1 , in which the apparatus comprises a port for providing an external connection to the acoustic transducer.  
   
   
       10 . An apparatus as claimed in  claim 9 , in which the port comprises a transmitter which provides a wireless link to a corresponding port of a leak localiser.  
   
   
       11 . An apparatus as claimed in  claim 1 , comprising a clock, the analysing means being arranged to analyse the parameter of the output signal of the transducer during night hours.  
   
   
       12 . An apparatus as claimed in  claim 1 , in which the analysing means is arranged to periodically measure the output level of the transducer and to provide an average of previously measured levels, the monitoring means being further arranged to determine said maximum and/or minimum values from said average.  
   
   
       13 . An apparatus as claimed in  claim 12 , in which the alarm signal is also generated, in the event that the parameter is above an absolute maximum value or below an absolute minimum value.  
   
   
       14 . An apparatus as claimed in  claim 12 , in which the monitoring means is arranged to reject readings from said average calculation, which are above a maximum threshold value or below a minimum threshold value.  
   
   
       15 . An apparatus as claimed in  claim 12 , in which the monitoring means is arranged to reject readings from the average calculation, which are a predetermined amount more or less than the median of the stored readings.  
   
   
       16 . An apparatus as claimed in  claim 12 , in which the monitoring means is arranged to only produce an alarm signal if a reading which is above said maximum limit or below said minimum limit is not substantially different from an adjacent reading.  
   
   
       17 . An apparatus as claimed in  claim 1 , in which the monitoring means is arranged to take a series of measurements of the output level of the transducer, the monitoring means being arranged to compare the level that has been exceeded for a predetermined percentage number of readings with said maximum or minimum values and/or to compare the spread between levels which have exceeded predetermined upper and lower percentage numbers of readings.  
   
   
       18 . An apparatus as claimed in  claim 1 , comprising a body having a port for connecting to a corresponding port in the wall of the pipe, a fluid-flow passage extending through the body and having opposite ends communicating with the port, an acoustic transducer mounted inside the flow passage, and flow diverting means for diverting at least some of the fluid flowing along the pipe through said flow passage.  
   
   
       19 . An assembly comprising a transducer for acoustically monitoring fluid flowing within a pipe, the assembly comprising a body having a port for connecting to a corresponding port in the wall of the pipe, a fluid-flow passage extending through the body and having opposite ends communicating with the port, an acoustic transducer mounted inside the flow passage, and flow diverting means for diverting at least some of the fluid flowing along the pipe through said flow passage.  
   
   
       20 . An assembly as claimed in  claim 19 , in which the flow diverting means is arranged to divert all of the fluid flowing along the pipe under analysis through the passageway.