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The ZONESCAN Correlating
Radio Logger system is the worlds most advanced digital
solution to detecting and locating leakage in water distribution
networks.
ZONESCAN has been developed
from the globally successful AQUASCAN 7000 leak noise correlator
and ZONESCAN 400 acoustic data logger.
The ZONESCAN system
provides the professional leakage engineer with the following
functions:
1. A fully programmable acoustic
logger
2. A digital leak locating correlator
3. A remote electronic listening device
4. Interpretation and database software |
A Fully Programmable Acoustic Logger
ZONESCAN loggers can be individually or collectively
programmed to suit each and every different leak detection and
location environment. The industry standard setting of 02:00am
to 04:00am at 1 second sampling is easily achieved as the loggers
can log up to 23 hours and 59 minutes. These results are then
presented in an easy to read format by the host software.
By utilising long recording window periods combined
with very rapid sampling, the ZONESCAN equipped leakage engineer
eliminates the phenomenon of “ghost leaks”, and therefore
eliminates the considerable wasted time trying to pinpoint leaks
that simply do not exist. Other less capable radio acoustic loggers
have been operationally proven to waste up to 50% of costly detection
time looking for “ghost leaks” in heavily populated
town and city districts.
ZONESCAN loggers function in a similar manner
to standard data loggers in that they “wake up” to
take recordings and when interrogated by the host software, (via
a PC or PDA device), and are “asleep” at all other
times to conserve the battery life. Based on a typical operational
pattern of one full download every 10 days, they will operate
continuously for 5 years before requiring battery replacement.
So that efficient and effective “leak patrols”
can be realised; ZONESCAN loggers have a 100mW transmission
power output, compared with the 3 -10mW transmission power outputs
of other less capable radio loggers. This allows the patrol vehicle
to interrogate and download the loggers at up to 250 metres away.
The operator sets the type of ZONESCAN patrol, dependant on
actual geographic restrictions, through the host software. This
leads to an average patrol of 72 loggers downloaded per hour,
compared with 28 loggers per hour for other permanently transmitting
types of radio logger.
At only 115mm high, with a flexible carrying handle
that houses the aerial, and with an all round aluminium casing,
the ZONESCAN logger is the smallest, lightest and most robust
logger available. Other radio loggers that have either fixed plastic
aerials or plastic housings, or both, are very prone to operational
damage such as imploding when chamber covers are replaced and
press down on the aerial, or when leakage inspectors accidentally
puncture the logger casing with listening sticks. Weighing less
than 0.4kg each, ZONESCAN loggers are easily transported and
deployed by one engineer.
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A) Project Table |
B) Measurements Graph |
Logged results are displayed on the
Project Table. These results are given 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 engineer sets the Leak Value in the host software
that determines if the result is indicated in either red or green.
This setting is also used for triggering the audio warnings if
required.
The Leak Value can be used to prioritise detection/confirmation
tasks. With the Leak Value threshold set to 30 quiet low volume
leakage, (such as weeping fire hydrants and passing boundary valves),
will be highlighted in red in the project table, and trigger an
audio warning, along with greater volume leaks. With the threshold
set to 50, these low volume leaks will be coloured green in the
Project Table and will not trigger an audio warning to the patrol
engineer. Because the patrol engineer sets this threshold level,
different logged areas with different average pressures and pipe
materials can be patrolled with appropriate settings improving
the effectiveness and efficiency of the patrols.
The logged decibel values for each logger are displayed
in the Measurements Graph. Each logger has a revolving memory
that will retain 10 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.
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Each ZONESCAN
Project Table can contain an unlimited amount of loggers.
We recommend setting up a different Project for each specific
DMA/LCZ, etc. This can assist in patrol planning and data
management. Each Project can be saved separately as a ZIP
file for archiving and/or mailing. |
A Digital Leak Locating Correlator
Each ZONESCAN logger can be programmed to record
a sample of actual pipe noise at any time of the day or night,
and this is done during 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.
Simply selecting a logger on the Project Table,
clicking on the Correlate icon, and then selecting the neighbouring
logger will carry out a cross correlation. Pipe details can then
be entered and the resultant graph will indicate the presence,
or otherwise, of a leak and it’s distance relative to the
first logger selected.
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A) Leak Located |
B) No Leak Indicated |
Carrying out correlations between loggers can help
in eliminating “ghost leaks”. If the logged decibel
levels from two adjacent loggers are both indicating a typical
leak noise pattern, by carrying out a correlation between these
two loggers the leakage engineer can determine if both loggers
are logging decibel levels from the same source, or if they are
logging levels of separate and unrelated noise sources. This quick
and simple correlation can be carried out on site or retrospectively
at the office eliminating wasted time trying to confirm the position
of a leak that does not exist.
On site real time correlation can also be carried
out with the ZONESCAN system. By communicating with the loggers,
the leakage engineer can program the loggers to record and digitise
another sound sample within minutes and then re-correlate with
these new sound samples. As with all correlation techniques: this
is best carried out at night to eliminate transient noise that
may distort the correlation result.
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ZONESCAN
loggers will continue to achieve good communication
range when completely submersed and when located in deep
chambers. |
A Remote Electronic Listening Device
Each ZONESACAN logger can be communicated with
in real time through the host software platform whenever the logger
is in communication range. The logger’s settings and amount
of logged data can be checked using the Logger State function.
Whilst communicating with the logger, the Remote Listen function
can be activated allowing the leakage engineer to listen to the
actual noise on the pipe in real time, as picked up by the logger’s
sensor.
This is another method that can be used to eliminate
“ghost leaks”. Experienced leakage engineers will
be able to distinguish between a “real” leak noise
and any alternative constant source of sound that will appear
as a potential leak on the Measurements graph.
All communication is carried out through the System
Communication Link. This is connected to a PC or PDA device via
a standard RS232 cable, and has an aerial with a magnetic base
for mounting on the roof of the patrol vehicle.
Interpretation and Database Software
The ZONESCAN host software has been designed
to be both simple to operate and yet very effective. For the patrol
operative that is unfamiliar with computers: the leakage engineer
can activate the patrol function, the operative simply drives
the designated route ensuring that the all the loggers on the
Project Table colour either green or red in sequence, and then
the interpretation is carried out by the leakage engineer when
the patrol returns to base.
ZONESCAN software has the following functions
as standard:
1. Graphical presentation of logged decibel
levels
2. Automatic cross correlation of recorded sound signals
3. Open or sequential communication options
4. Remote listening to actual pipe noise
5. Audio indication of Leak Value thresholds
6. Audio indication of logger serial numbers
7. Audio indications of logger locations
8. Audio indications of logger communication status
9. Map importing
10. Map patrolling
11. Leak Value threshold setting
12. Project Import and Export
Various types of mapping files can
be imported into the ZONESCAN software. These can then used
for leak detection and location purposes.
A patrol can be guided by this display on the PC
if required. At the start of a patrol all the logger icons will
change colour to grey to indicate that they have not yet been
downloaded. As communication is initiated with a logger, a red
square outlines the logger and when the download is complete the
logger icon will change colour to either red or green, depending
on the Leak Value threshold set by the operator.
Audio Indications
The core design specification for the ZONESCAN
system was to enable the leakage engineer to achieve a fast and
accurate leak detection and location survey in a target area.
To achieve this ZONESCAN software uses unique “Voice
Notification” to keep the patrol operative aware of the
progress of the patrol without ever having to consult a display.
The software default settings are:
“Logger Found” - the software has initiated communication
with a logger
“No Leak Indicated” - a downloaded leak value is below
the warning level threshold
“Caution. Leak Indicated” - a downloaded leak value
exceeds the warning level threshold
“Synchronization Terminated” - the logger has been
completely downloaded and communication has finished
“Synchronisation Failed” - the logger has not completely
downloaded
“Caution. Logger Battery Weak” - the logger battery
is below the warning level
The operator can change these settings to suit operational
requirements
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In addition individual loggers
can be “voice tagged” with both their logger
number and a location, such as an address. Individual logger
audio recordings are stored in the host software platform.
During a patrol, logger audio
indications will be announced after “Logger Found”
to inform the patrol operative of the identity and location
of the logger currently being downloaded.
The audio indications can
be heard through PC/PDA speakers, headphones, or through
the vehicle radio/cassette. |
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