Zonescan correlating loggers, available from Gutermann , are deployed throughout the water distribution network at regular intervals (often attached to valve spindles or fire hydrants via the integrated magnetic base).
The spacing between Zonescan correlating loggers depends on the pipe material, typically 80 metres for PVC Pipes, 100 metres for AC and 130 metres for iron pipes.
The Zonescan correlating loggers continuously monitor and analyse noise characteristics within the distribution system and can detect and identify the presence and location of a leak.
Once in range of a Zonescan correlating logger, a patrol operator will receive automatic notification from the systems voice embedded host software, first identifying the unit, before announcing the presence or probability of a leak at that point in the water network.
If audible confirmation of the leak noise is desired, the operator can, at any time, listen directly to the digitally transmitted leak noise.
Logged results are displayed in the software database as a 'Project Table'.
Each result is given as a ‘Leak Value’ between 0 and 100 for initial interpretation. This Leak Value is determined by the level and occurrence of the logged decibel readings. The operator sets the 'Leak Value threshold' within the host software.
This determines whether the result is indicated in red (caution, probable leak), orange (possible leak) or green (no leak). The same threshold is also used for triggering the audio warnings if required.
The Leak Value can be used to prioritise detection/confirmation tasks. For example, with the Leak Value threshold set to '30', quiet, low volume leakage (such as weeping fire hydrants and passing boundary valves) may still be highlighted in 'orange' in the project table, along with greater volume leaks.
With the threshold set to 50, these lower volume/priority leaks will be coloured 'green' in the Project Table and will not trigger a leak audio warning to the patrol engineer.
Because the patrol operator sets this threshold level based on his local knowledge of the network, different logged areas with different average pressures and pipe materials can be patrolled with improved effectiveness and efficiency.
The logged decibel values for each logger are displayed in the Measurements Graph. Each Zonescan correlating logger has a revolving memory that will retain 30 days of measurements graphs and 180 days of Leak Values, with the oldest value being overwritten when the memory is full.
The storage of historic information is only limited by the host PC’s memory. An ‘acoustic fingerprint’ can be built up and viewed in the Measurements window allowing a degree of local asset appraisal to be carried out.
Each Zonescan 800 Project Table can contain an unlimited amount of loggers.
A different 'Zonescan Project' is recommended for each specific D.M.A./L.C.Z. as this can assist in patrol planning and data management. Each Project can be saved separately as a ZIP file for archiving and/or emailing.
Measurement Graph shows noise levels and consistency of noise
With the decibel scale on the X axis and quantity of samples recorded at the noise level on the Y axis this graph indicates a typical leak profile with a narrow peak on the upper decibel level.
A digital leak locating correlator
in addition to noise logging, each Zonescan correlating logger can also be independently programmed to record a sample of actual pipe noise at any time of the day or night, and this is performed during synchronisation (programming or downloading).
This noise sample is then digitised and stored in the logger’s memory for onward transmission when the logger is interrogated by the host software platform. These digitised noise files are stored in the Noise Signals section of the Zonescan software to enable cross correlation between loggers to pinpoint the source of the leak noise between any two loggers.
Simply selecting any two loggers from the Project Table, then clicking on the 'Correlate' icon, enables the user to conduct a cross correlation. For exacting accuracy, pipe details can be entered and the graph will then indicate the precise distance of any leak in relation to the first logger selected.
New automatic multi-test correlation between all loggers in the same project
Zonescan software now offers the user another new feature. By simply selecting a dedicated 'test correlation' icon within the Zonescan's correlation programme, the host software will perform a test correlation between all zonescan correlating loggers within the same project.
Using specific correlation formulae, the Zonescan-800 will then provide the user with a list of all the highest probable leak positions.