| 摘要 |
PCT No. PCT/GB83/00341 Sec. 371 Date Aug. 30, 1984 Sec. 102(e) Date Aug. 30, 1984 PCT Filed Dec. 22, 1983 PCT Pub. No. WO84/02788 PCT Pub. Date Jul. 19, 1984.A device for under-water signalling has a chamber (38) which is normally closed by a replaceable element (39). A cartridge (16) in the device can be fired to release gas into the chamber and rupture the element (39), thus causing a sound wave to travel through the water and releasing the contents of the chamber into the water. When an end cap (13) has been removed to prepare the device for use, water pressure can act on a piston (23) to cause firing of the cartridge. |
