CN114623916A - A Fiber Bragg Grating Hydrophone Using Double Conical Truncated Diaphragm - Google Patents

Abstract

The invention relates to a fiber grating hydrophone using a double-cone frustum diaphragm, and belongs to the technical field of optical fiber hydrophones. The outer side of the support cylinder is covered with a sound-transmitting rubber sleeve, and the left and right shells are respectively fixed on both sides of the support cylinder. The copper sheet and the right copper sheet are used to fix the fiber grating, and the fiber grating passes through the hole on the central axis of the hydrophone. The advantage is that the volume change of the oil cavity caused by the sound pressure is converted into the length change of the fiber grating by using the frustum-shaped diaphragm, and the structure is simple. The way of fixed connection increases the reliability and stability of the structure.

Description

A Fiber Bragg Grating Hydrophone Using Double Conical Frustum Diaphragm

technical field

The invention belongs to the technical field of optical fiber hydrophones, and in particular relates to a fiber grating hydrophone using a double-cone frustum diaphragm.

Background technique

Sound waves are the only form of energy known to man that can travel long distances in seawater. A hydrophone is a type of sensor used to detect underwater sound waves for navigation, measurement and communication. Traditional hydrophones can be divided into electric type, capacitive type, piezoelectric type, etc. according to the principle of detecting underwater acoustic signals.

In recent years, with the rapid development of fiber light source, fiber spectrometer and fiber grating processing technology, fiber grating hydrophone with high performance, miniaturization and high stability is gradually called a new generation of underwater acoustic detection sensor. The fiber grating hydrophone with fiber grating as the sensing source has received extensive attention from domestic and foreign scientific research institutions and scholars in the fields of national defense, military, detection and other applications, and related technologies have achieved unprecedented development. Compared with other types of hydrophones, fiber grating hydrophones have the advantages of low noise, high sensitivity, large dynamic range, and excellent reliability. The packaged optical fibers are used as connectors, which are very suitable for forming large-scale hydrophones. Arrays, fiber optic hydrophones have been used by many countries as key R&D investment in national defense technology equipment.

The fiber grating sensor realizes the sensing function by using the optical waveguide characteristics of the optical fiber and the grating to reflect specific wavelengths and has the modulation effect of sensing specific parameters in the environment. sound signal. Compared with traditional piezoelectric hydrophones, fiber-optic hydrophones mainly have the following advantages: wide frequency band, high sensitivity, no electromagnetic interference, small mass, small volume and simple structure, combined with fiber-optic light source and fiber-optic spectrometer, can be integrated It has great application prospects.

At present, improving the pressure sensitivity of FBG hydrophones, using filtering structure to constrain the working frequency range of FBG hydrophones, and improving the structure to adapt to specific applications are the current development directions of FBG hydrophones. How to solve the problem of large acceleration response and high low-frequency noise is an important technical problem in the current fiber optic hydrophone, which needs to be further explored and improved.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to increase the reliability and stability of the fiber grating hydrophone during operation by introducing a truncated cone-shaped diaphragm and a way of fixing the diaphragm and the main structure, so as to solve the problem of using a piston-type flat-shaped diaphragm in the prior art. During the working process of the diaphragm fiber grating hydrophone, due to the relative movement of the diaphragm and the structure, the sealing structure will fail, the relative movement will lead to wear, the life of the structure will be reduced, and the sensitivity to the feedback of the underwater acoustic signal will eventually be insufficient.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

The outer side of the supporting cylinder (7) is covered with a sound-transmitting rubber sleeve (3), the two sides of the supporting cylinder (7) are respectively fixed to the left casing (1) and the right casing (5), and the supporting cylinder (7) is symmetrically fixed inside The left frustum-shaped diaphragm (201) and the right frustum-shaped diaphragm (401) are provided with a left copper plate (202) and a right copper plate (402) for fixing the fiber grating (6), the fiber grating (6) Pass through the hole on the central axis of the hydrophone; the gap between the fiber grating (6) and the contact position of the hydrophone is filled with sealing material; the left casing (1) and the supporting cylinder (7) and the left frustum diaphragm (201) ) to form a closed cavity; the right casing (5), the support cylinder (7) and the right frustum diaphragm (401) form a closed cavity; the left frustum diaphragm (201), the right frustum diaphragm (401), The support cylinder (7) and the sound-transmitting rubber sleeve (3) form an oil cavity, which is filled with oil; the middle of the support cylinder (7) has holes on the upper and lower sides for transmitting the sound pressure in the water.

The advantages of the invention are that the volume change of the oil cavity caused by the sound pressure is converted into the length change of the fiber grating by using the frustum-shaped diaphragm, and the structure is simple. The way of fixing the support cylinder increases the reliability and stability of the structure.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is a side sectional view of the central axis of the present invention.

Detailed ways

1 and FIG. 2 , the present embodiment is described in detail. In the fiber grating hydrophone using a double-cone frustum diaphragm described in this embodiment, the outer side of the support cylinder 7 is covered with a sound-transmitting rubber sleeve 3 , and the support cylinder 7 The left casing 1 and the right casing 5 are respectively fixed on both sides, and the left conical frustum diaphragm 201 and the right frustum diaphragm 401 are symmetrically fixed inside the supporting cylinder 7, and the left copper sheet 202 and the right copper sheet 402 are installed on the diaphragm. For fixing the fiber grating 6, the fiber grating 6 passes through the hole on the central axis of the hydrophone; the gap between the fiber grating 6 and the hydrophone contact position is filled with sealing material; the left casing 1, the supporting cylinder 7 and the left frustum-shaped membrane The sheet 201 forms a closed cavity; the right casing 5 forms a closed cavity with the support cylinder 7 and the right frustum diaphragm 401; the left frustum diaphragm 201, the right frustum diaphragm 401, the support cylinder 7 and the sound-transmitting rubber sleeve 3. An oil cavity is formed, and the interior is filled with oil; there are holes on the upper and lower sides of the middle of the support cylinder 7, which are used to transmit the sound pressure in the water.

The working principle of the fiber grating hydrophone in the present invention is as follows: when the hydrophone receives the sound pressure of water underwater, the sound pressure will act on the oil in the oil cavity through the sound-transmitting rubber sleeve 3, and the oil will be absorbed by the water. Squeeze and transmit the pressure to the left and right frustum-shaped diaphragms 201 and 401 fixed on the support cylinder 7, the left and right frustum-shaped diaphragms 201 and 401 undergo axial deformation, and The deformation is transmitted to the fiber grating 6 fixed between the left copper sheet 202 and the right copper sheet 402. When the fiber grating 6 is deformed axially, the wavelength of the reflected light will change. By measuring the reflected light in the fiber grating 6 The corresponding underwater acoustic information can be obtained.

Claims (1)

1. A fiber grating hydrophone adopting a double-cone frustum diaphragm, comprising: a left casing (1), a left frustum diaphragm (201), a left copper sheet (202), a sound-transmitting rubber sleeve (3), The right frustum-shaped diaphragm (401), the right copper sheet (402), the right casing (5), the fiber grating (6), and the supporting cylinder (7) are characterized in that: the outer side of the supporting cylinder (7) is covered with sound-transmitting The rubber sleeve (3), the left casing (1) and the right casing (5) are respectively fixed on both sides of the supporting cylinder (7), and the left conical frustum diaphragm (201) and the right cone are fixed symmetrically inside the supporting cylinder (7). a table-shaped diaphragm (401), a left copper sheet (202) and a right copper sheet (402) are installed on the diaphragm for fixing the fiber grating (6), and the fiber grating (6) passes through the hole on the central axis of the hydrophone; The gap between the fiber grating (6) and the hydrophone is filled with sealing material; the left casing (1) forms a closed cavity with the supporting cylinder (7) and the left frustum-shaped diaphragm (201); the right casing (5) A closed cavity is formed with the support cylinder (7) and the right frustum diaphragm (401); the left frustum diaphragm (201), the right frustum diaphragm (401), the support cylinder (7) and the sound-transmitting rubber sleeve (3) An oil cavity is formed, and the inside is filled with oil; there are holes on the upper and lower sides of the middle of the support cylinder (7), which are used to transmit the sound pressure in the water.

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