Sound-signal warning device for higher safety of navigation

Purpose

Development of a set of new small-size sound-signal devices for ships, which are intended for signaling and preventing collisions in poor visibility conditions. The sound-signal device complies with the International rules of collision prevention for ships in the sea in poor visibility conditions, according to which the frequency range, the acoustic power of the signal, and the audibility range must correspond to the length of the ship (from 20 m and up to 200 m and above).

Structure and principle of operation Prototype of the sound-signal device

The device is designed on the basis of the structure of gas-dynamic radiators that comply with the aforementioned International rules and provide simple and reliable operation on board of any kind of ships with the use of compressed-air pipelines. The principle of operation of gas-dynamic radiators is based on the excitation of the volumes of 1/4 wave resonance cavities by air jets flowing through them (the air jets are formed by confuser nozzles).

Degree of readiness

Technical methods of designing a set of sound-signal devices are developed, technical parameters and the principles for optimizing the structure of the main units are determined. A prototype of a sound-signal device with a gas-dynamic radiator is manufactured and tested in different environmental conditions.
Sound pressure level at the outlet of the sound-signal device Sound pressure level at the outlet
of the sound-signal device

According to the test data, in the frequency range 150-380 Hz, the sound pressure level at a distance of 1 m was about 150 dB, the maximal level of 155 dB being reached in the frequency band 180-200 Hz. The air pressure at the radiator inlet was 2 to 3 atm, and the air flow rate through the nozzle was 0.1 kg/s. According to the International rules, for ships 100 to 200 m long, the recommended frequency range is between 150 and 350 Hz with the sound pressure level at 1 m no less than 138 dB. The tests demonstrated the efficiency of the designed sound-signal device with a gas-dynamic radiator.

The Acoustics Institute is interested in a partnership affiliation to bring a sound-signal device to perfection.