The Ultrasonic Siren Applied on Seagoing Ships for Defogging the Ranges of Vision

摘要

1,154,020. Ultrasonic siren. M. VIOS. 5 Sept., 1966 [8 Sept., 1965], No. 39649/66. Heading G5J. [Also in Division A1] An ultrasonic siren generates two trains of waves in anti-phase to produce a standing wave pattern for dispersing fog. Compressed air enters at 19, 20 at opposite ends of a easing and passes through nozzles formed by oblique apertures in plates 9, 10 to impinge on turbine rotors 5, 6 and pass along tubular shafts 1, 2 which connect the rotors with concentric contrarotating drums 3, 4. Each drum has two similar sets of holes. One set on the drum 3 registers with one set on the drum 4, as shown, while the other two sets mask one another. Two trains of waves are thus produced in antiphase by the alternate registering and masking of the two pairs of sets of holes. The two trains are projected into the annular space between curved members 11, 12. The siren is mounted in a parabolic reflector 21.