Lokal 400 Operating Manual
Page 6
5. Powering up and operating the device
The Lokal 400 leakage detector and its measurement boxes are equipped with internal nickel metal
hydride batteries. Please make sure that the batteries are fully charged before the device is powered up.
The Lokal 400 multi-functional detector system is capable of carrying out both correlations and
electroacoustic listening procedures. These two separate functions are described in detail below.
5.1 Powering up for correlation
Headphones:
Connect the headphones to the headphone jack of the LOKAL 400, if required [see
Chapter 4, legend
item no. (7)
]. Please exclusively use the original headphones for your measurements. The headphones
are applied to listen to the noises transmitted by the transmitters A/B/C or by the ground microphone/other
microphones. This data is then used to set the filters and the amplification level of the leakage detection
equipment.
Transmitter:
The measurement boxes (MB3 / MB4 / MB5) of the Lokal 400 leakage detection system are equipped
with sensors. The boxes have to be positioned on the leaking pipe for leakage search operation. It is
recommended to keep the distance between the two transmitters/sensors as short as possible. Once the
sensors have been attached and the measurement boxes have been switched on, the noise level
indicator on the measurement box should indicate a certain noise level.
If this level is around “0” and there
is no noise to be heard, the distance to the leakage has to be reduced or another type of sensor has to
be selected for the leakage detection procedure.
Basically, there are two different types of sensor available:
-
Accelerometer sensor [Chapter 3, (2) or (3)]
-
Hydrophone sensor [Chapter 3, (10)]
The accelerometers have been developed to meet the requirements of leakage detection on metal pipes.
They are attached to the pipe with a magnet at accessible spots such as hydrants, valves or in manholes
and pick up the sound travelling along the particular pipe.
Hydrophone sensors have been developed to meet the requirements of leakage detection on non-metal
pipes (plastics) and have to be in direct contact with the water column at hydrants or at other accessible
connections. The sensors pick up the sound travelling in the medium (water).
Therefore, the material of the particular pipe to be checked has to be identified beforehand in order to be
able to apply the appropriate type of sensor.
For further information on the operation of the measurement boxes, please refer to the Measurement
Boxes Operating Instructions. In general, the following approach is recommended:
1. Attach the sensors to the pipe
2. Switch on the measurement boxes
3. Select amplification and appropriate filters
Sensors:
The Lokal 400 system is capable of correlating a noise through the transmitters A/B/C and is also capable
of using another source of noise for its calculations through the direct sensor connection at the central
unit. If you wish to connect a sensor to the LOKAL 400 device, please use the sensor jack [
see Chapter
4, legend item no. (7)
]. A more detailed description of the different sensors and their particular fields of
application is stated below.
Lokal 400 central unit:
