Kongsberg EM 122, Руководство по установке

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EM 122
with sharp bows, deep drafts and ideal acoustic conditions this installation method might
be acceptable. If this method is selected, great care must be taken during the planning
solution to ensure best possible transducer location.
For ice breakers there is no other alternative than a flush installation, the transducer
are then protected behind ice windows.
Note
This installation method may prove unsuccessful due to aerated water blocking the
signal path to and from the transducers. Thorough research on the vessel’s hull design
and the acoustic conditions must be made before attempting this installation method.
Fairing
The transducer arrays may also be mounted directly under the vessel’s hull and then
“streamlined” with fairing. This installation method has proven successful in former
multibeam echo sounder installations. The required installation drawings must be made
by the installation shipyard or by third-party ship designers.
Protective acoustic window
Description of a acoustic window
Acoustic windows may be supplied for low frequency, 12 and 30 kHz multibeam echo
sounders only, i.e. the EM 122 and the EM 122. For multibeam echo sounders with
higher frequencies, such as the EM 710, acoustic windows will be too lossy, thus
specially made ice strengthened transducers will be the solution.
An EM 122 multibeam system can be installed on ice going ships, from ice rand ships
with the lightest ice class to a full ice breaker classified vessel.
Both the transmit and the receive transducers are then integrated into the ship’s hull and
are protected behind acoustic windows.
The ice window construction for the TX transducer and the RX transducer windows
are different.
The TX window consists of several square windows bolted in front of the transducer.
Each window is 840 mm wide and 640 mm long. The thickness is 70 mm. The amount
of windows is given by the transducer size, from 2 to 8 units. The windows are bolted
side by side inside a transducer casing with a minimum distance of 2 mm apart. The bolt
size is M20x70 together with Nor Lock washers. Torch to be used is 280 Nm.
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