The underwater acoustic transducer for receiving underwater acoustic signals is called a water hammer, and the hydrophone includes a piezoelectric type, a magnetostrictive type, a moving coil type, and a piezoresistive type. Here, we mainly introduce vector hydrophones that sense underwater vector signals and fiber optic hydrophones that are based on photoelastic effects.
new technology vector hydrophone :
The information of the underwater sound field includes parameters such as sound pressure gradient, particle acceleration, particle velocity, and particle displacement. A class underwater acoustic transducers that sense these vector information is called a vector hydrophone. Currently, the vector hydrophone is domestic and foreign applications have become a hot research direction one. According to the way the transducer interacts with the sound field, the vector hydrophone can be divided into a dual hydrophone type, a housing static type, a vibration type and the like. The dual hydrophone type is relatively intuitive. It uses a pair of sound pressure hydrophones to measure the sound pressure gradient of two points close to each other. The design of pzt piezoceramic cylinder is a heavy mass, and the sensitive components are connected to the outer casing are directly. Acting with the sound field to detect the differential pressure signal, through the flexible frame of the fixed frame (or column), the ball (or an average density of the column is approximately equal to the water, the scale is much smaller than working wave) and the body vibrates with the water medium. the sound wave does not directly act on the sensitive component, but is transferred from the inertial force to the sensitive component connected to the internal mass. The outstanding feature of vector hydrophones is that they have dipole directionality and therefore have important applications of underwater ultrasonic depth transducer. .
Fiber Optic Waterjet Technology:
A fiber optic hydrophone is a kind of water sensing device that senses the intensity, polarization, phase, etc. of the propagating light in the fiber caused by the acoustic signal in the sound field.About acoustic signal sensor, the more common type is the interference fiber optic hydrophone. The structure and pick-up principle of an interferometric fiber-optic hydrophone are given. piezoelectric transducer ultrasound uses the optical fiber phase to detect the phase change caused by the acoustic signal to detect the underwater acoustic signal. The fiber-optic hydrophone has the characteristics of high sensitivity, anti-electromagnetic interference and easy formation. This type of fiber-optic hydrophone is used for offshore array test, and a three-dimensional vibration interferometric fiber-optic hydrophone is developed. In recent years, fiber grating hydrophones have been developed. The so-called fiber grating is a technique to change the refractive index distribution of the fiber core in a certain period in the longitudinal direction. The fiber hydrophone is based on the principle that the center wavelength of the grating moves with the perceived acoustic parameter. At present, the fiber grating water raft is generally based on the principle of fiber bragg grating to realize underwater acoustic signal detection. In addition to the high sensitivity of the interferometric fiber-optic hydrophone, electromagnetic interference, and long-distance transmission, the fiber-optic hydrophone has the characteristics of miniaturization of the probe and easy wavelength division multiplexing. In addition, the simultaneous detection of underwater multi-point signals can be realized by writing a plurality of different wavelength gratings on one optical fiber, piezoelectric tubular transducer makes the hydrophone array more convenient.
Hubei Hannas Tech Co.,Ltd is a professional piezoelectric ceramics and ultrasonic transducer manufacturer, dedicated to ultrasonic technology and industrial applications.
