Portable Correlator with “Fully Loaded” Ground Microphone Capabilities
to Find Water Leaks in Water Networks
What is correlation?
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Correlation is
a way of finding and pinpointing leaks in water pipes.
A leak in a pipe under pressure creates noise that travels
through the pipe walls, the surrounding ground and along
the contents of the pipe. If two highly sensitive microphones
are attached to two different locations on a pipe with a
leak the sound from the leak will take longer to travel
to the microphone furthest from the leak; this is referred
to as the “time delay” or ∆t. Utilising this and other
information (pipe diameter, material and length of section
under test), the exact leak position can be calculated by
the correlator SeCorrPhon AC 06. |
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Water Leak Correlation Theory
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Advantages of using correlators to
find water leaks
Using listening sticks or ground microphones alone as methods
of water leak detection can be affected by external noise interferences
such as cars, wind etc. The correlator SeCorrPhon AC 06 is unaffected
by these interferences making water leak detection possible in
even the noisiest environments. Other surrounding influences including
the depth of pipe, ground conditions and rain have no effect on
the accuracy of results. When using electro-acoustic devices the
operator’s experience and sense of hearing is paramount. Correlation
is based on purely mathematical calculations consequently the
reliance on the operator’s subjective views are eliminated allowing
anyone with minimal training to carry out leak location. |
Precise water leak location with
Digital Signal Processing
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The two microphones
are attached by magnet, or valve adaptors, to hydrants,
valves, the pipe walls or even directly into the water column
using hydrophone sensors. As long as the leak noise can
be “heard” by both microphones the SeCorrPhon AC 06 can
process and analyse the resulting information. |
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The sounds picked up by the
microphones are transmitted via two powerful 500 mW radio
transmitters to the lightweight central processing unit
SeCorrPhon AC 06 Digital Signal Processor where the
information is quickly analysed & the resulting leak position
is displayed both graphically and numerically, in metres
to the leak from each sensor. If the leak lies outside the
measuring section the SeCorrPhon AC 06 correlator
will let you know; you should then move the sensors to different
positions as the ideal is to get the leak as close as possible
to midway between each sensor. |
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SeCorrPhon AC 06 - Radio transmitters
and Piezo accelerometers
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The noise from
the microphones is transmitted to the central control processor
by two powerful radio transmitters
- Lightweight radio transmitters which can easily be
carried in one hand by the antenna carrying buttons
- Automatic on/off when the microphone is plugged in/out
- no danger of running the battery flat by mistake
- Automatic best amplification level selected when microphone
connected
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- In built low pass frequency filter - Ideal for plastic
pipes; It highlights and emphasises sounds in the range
0-300 Hz which is where leak noises are more likely
to be propagated on this material
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- The receiver and radio transmitters can all be charged
in the closed case doing away with the nuisance of having
multiple component parts plugged into various sockets
around your office.
- Charging can also be carried out in your car or van
via the 12V cigar lighter lead or permanently hard wired
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Direct microphone connection
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- In the event of accidental damage to a radio transmitter
either microphone can be plugged directly into
the SeCorrPhon AC 06 allowing you to carry on working
without interruption.
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Hydrophones Best performance for
finding leaks in plastic pipes
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- Hydrophones are Piezo accelerometers which are attached,
via hydrants, directly into the water column (as opposed
to on the external surface of the pipe) so even very
quiet water leak noise can be heard far more successfully.
- They are particularly useful on plastic pipes and
trunk mains where sounds does not travel as well as
on cast and steel pipes
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SeCorrPhon AC 06 - Firmware and
Software
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With the SeCorrPhon AC06 software
you can:
- Analyse field tests on your PC or laptop. This can
be very useful where a test gives a good indication of a leak
but the other input data is unreliable, such as pipe material,
or size. The results can be recalculated back in the office
to give the correct leak location without the need to carry
out another correlation. This can be carried out on the PC
or on the SeCorrPhon AC 06 itself
- E-mail: Test results can be sent by email for comment
or assistance from Sewerin
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- Reports: PC software produces clear reports
including: Your address, client’s address, operator,
leak location, material, diameter, coherence, correlation
and a pictorial representation of the leak location
(professional)
- Record leak noise: Real leak noise sound can
be recorded which allows users to listen to noises away
from the field for later comment and interpretation,
perhaps by more experienced staff (professional)
- Zoom: Zoom function on display - Gives added
clarity to suspect readings
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SeCorrPhon AC06: Not Just a Correlator
but also an Advanced Ground Microphone
For a number of reasons correlation
is not a fool proof science, (much as we all wish it were
so!)
After correlation has been carried out it is always advisable
that the indicated leak position should be checked by listening
on the ground above the suspected leak location. With other
correlators this would mean having to purchase a separate
ground microphone - not so with the SeCorrPhon AC 06.
There are also times when it is impractical to use a correlator
and the only way of locating a leak is to use an acoustic
listening instrument. With the SeCorrPhon AC 06 there is
no need to purchase another instrument.
It is also a fully featured ground and valve microphone
device having ALL the features of our standalone ground
mic system A100
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By attaching a tripod directly onto the base of the correlator
microphone or by using any of our dedicated ground microphones
used with the Aquaphon, the SeCorrPhon AC 06 recognises that you
want to use it as a ground mic. and the display shows the following
functions: |
Minimum Noise Level Memory Function
- Assistance In Finding Water Leaks
- Current “lowest” noise level: - A leak noise does
not get quieter but traffic and wind noise will increase and
decrease.
The SeCorrPhon AC 06 ignores all these interfering noises
digitally displaying only the “quietest” it has been during
the time you have been listening. The current “actual” noise
level is also displayed as an analogue bar graph. This is
a constantly moving display depending on ambient noise levels.
- Memory: The last lowest noise level is stored and
displayed. Are you closer or further away from the leak in
the current listening position compared to the last?
Is the leak sound getting louder or quieter? The higher the
number on the display the closer to the leak you are.
- Amplification: There are three levels of amplification
(as well as the volume control). The amplification level can
be selected to best suit the noise level being listened to.
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Dynamic Hearing Protection Function
With normal acoustic detection instruments an uncomfortable, sometimes
painful and dangerous, noise is heard when the test rod slips
from the contact point, or the headphones are activated too soon,
or not soon enough, or some comedian bangs their foot to see if
you "can hear". The SeCorrPhon AC 06 incorporates a novel technology
to makes this danger a thing of the past. When a very loud noise
is picked up the sound in the headphones is immediately muffled.
If the sound increases even further, the headphones are switched
off completely. |
Frequency Filter - Water Leak Noise
Optimised Listening
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We do not all hear best at
the same frequencies; some people prefer listening at high
frequencies others to lower.
Leaks do not all produce noise at the same frequency.
Sometimes interfering noises make listening at certain frequencies
very difficult. The SeCorrPhon AC06® has a number of ways
to assist with all these problems... ...SUIT YOURSELF:
By applying your own choice of frequency filters you can
listen to any frequency range that you wish which best suits
the leak noise being listened to, your hearing and to filter
out interfering noises, all selected by the push of a button.
...LET THE SeCorrPhon AC06® HELP:
If you are unsure of what filters to use the SeCorrPhon
can be easily used in “Band Pass” mode utilising pre-defined
filter settings.
The filter-optimisation function makes it easier to detect
leaks even when the sound is very muffled. By activating
the frequency filter button the receiver takes a noise sample
which is then analysed & the optimum frequency range is
set and filtered. This can greatly assist those with less
experience making the sound of the leak particularly clear.
...AUTOMATIC BEST SETTINGS: When a microphone
is plugged in the SeCorrPhon® automatically recognises which
model it is and sets the best filter range. If you have
chosen an alternative setting it defaults to the last settings
you chose; The SeCorrPhon® even turns itself on and off
when you plug the microphone in or out |
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SeCorrPhon AC 06 - Features
- Very quick and easy to use intuitive operation sequence
(can be operated by only four buttons)
- Input data via Jog dial and / or water resistant film
pad – Users can select one or both methods according
to their personal preference
- Automatic background interference noise suppression
- Utilises the latest Digital Signal Processor (DSP)
provides fast accurate calculations ensuring quicker
leak location
- Fast Fourier Transformation (FFT) correlation – precise
fast location even with the most challenging leaks
- High resolution 320 x 240 pixel display – Clear precise
visualisation of leaks, even in bright sunlight
- “Highest Peak” (likely leak location) automatically
selected- This can be moved by the operator to look
at other suspicious indications
- Many “Drill down menu” advanced features, comparable
to PC driven correlators, are available for times that
you need to use their advantages & out of the way when
you do not
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SeCorrPhon AC 06 - Technical Information
Receiver
- Display 320 x 240 pixels with bright background LED
illumination
- PC connection for information download Socket for
direct connection of a variety of microphones
- BNC connector for antenna input with 90 deg rod aerial
(rotary)
- 1 or 2 radio channels
- Built in NiMH rechargable batteries and 12V socket
for direct power or charging from vehicle Approx. 8
hours use
- Operating/storage temperature: -10 °C … +40 °C / -20
°C … +60 °C
- Protection class: IP 54
- Weight: approx. 1.3 kg
- Dimensions (W x H x D): approx. 12.5 x 18 x 6.5 cm
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SeCorrPhon AC 06 - Technical Information
Radio transmitter RT 06
- Automatic microphone recognition when attached
- Automatically on when microphone connected
- Selectable low-pass filter to increase performance
on non-metallic pipes
- Automatic signal control
- 500 mW output power level with optimal selectivity
- Operating/storage temperature: -10 °C … +40 °C / -20
°C … +60 °C
- Protection class: IP 67
- Weight: approx. 1.3 kg
- Dimensions (W x H x D): approx. 12.5 x 19 x 7.3 cm
- Operating time: approx. 10 hours
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