RU25969U1 - HYDROACOUSTIC CONVERTER - Google Patents

Description

Hydroacoustic transducer.

The utility model relates to hydroacoustic technology, and can be used in the design of hydroacoustic transducers that are part of hydroacoustic antennas, or single measuring hydroacoustic transducers.

At present, the most technologically advanced is sealing the active elements of sonar transducers with polymer compounds 1 or rubber coatings 2, p. 124.

This raises two problems associated with this type of sealing:

- low service life for waterproofing, due to the property of polymeric materials to adsorb water 3 and

-the need for electrical effaning of the active element from the action of external electric fields.

Acoustic transducers are known, in order to increase their waterproofing, the sealing polymer compound is applied in several layers with different characteristics 4, 5. However, it is not possible to radically solve the waterproofing problem in these structures, since all polymers are permeable to water. In addition, the process of forming a sealing loop from several layers with different characteristics is, in principle, multi-stage, which significantly complicates the technology and the manufacturing time of the converter.

MPKN04R17 / 00, H04R1 / 44

Known sonar transducer 2, containing the active element, which is a single cylindrical piezoelectric element, sealed with a rubber coating and having an electric screen in the form of a metal mesh, separated from the rubber coating by a gap. Such ethane does not affect the waterproofing of the sonar transducer, since it is water-proof, and the screening efficiency of such a screen is low, because it depends on the perforation coefficient of the metal mesh, which also has direct contact with the aqueous medium when the transducer is operating.

The closest set of features to the proposed utility model is a sonar transducer, described in 2 on page 125. This sonar transducer, like the previous analogue, contains an active element made on one cylindrical piezoelectric element. The active element is sealed with an elastic polymer compound. On the outer surface of the active element by metallization, a thin metal coating is applied, which is an electric ethane.

The disadvantage of the sonar transducer prototype is the short service life of waterproofing and insufficiently effective electrical shielding, in addition, its manufacturing technology is complex and expensive. Indeed, it is practically impossible to achieve continuity of the metal coating by metallizing the polymer surface, even when metallizing in several layers, especially if the sonar transducer has a complex shape, sharp edges, etc., and direct contact of the electric screen with water at

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the work of the sonar transducer, significantly reduces the effectiveness of shielding.

The objective of the utility model is to increase the service life of waterproofing, to improve the electrical effecting of the sonar transducer while increasing manufacturability and reducing the cost of the sonar transducer.

To solve this problem, in the known hydroacoustic transducer containing an active element sealed with an elastic polymer compound made of at least one piezoelectric element, electric ethane and cable, new features are introduced, namely: the electric screen is made in the form of a casing of metal foil and is electrically connected to with the cable ethane, an active element is located in the inner cavity of the casing of metal foil, and a piezoelectric element is located on the outer surface normal to the surface of the electrodes ntov, the housing of a metallic foil, has two technology holes for filling an elastic polymeric compound its inner volume, located opposite each other on opposite sides of the active element, wherein the outer side of the casing of a metal foil coated with a layer of flexible polymeric compound, encapsulating the active element.

The maximum effect on waterproofing and electrical shielding is achieved if the technological holes are made so that they can be foiled with foil after filling the internal volume of the casing of metal foil with elastic polymer compound.

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transducer service life for tightness and increased noise immunity from external electric fields. An increase in the service life of the sonar transducer for tightness is achieved due to the fact that the electric screen made of metal foil is an ideal obstacle for the penetration of water to the electrodes of piezoelectric elements. Even if there are technological holes in the casing, they are made on the side of the side surfaces of the active element, where it is possible to increase the total layer of the elastic polymer compound to a size guaranteed to provide the specified service life without compromising the acoustic parameters of the hydroacoustic transducer.

The high efficiency of eleganric ethane is explained by the fact that the outer surface of ethane is separated from water by a layer of an elastic polymer compound, which is a dielectric, while the technological holes are located on the side of the side surfaces of the piezoelectric elements and perpendicular to the surface of the piezoelectric electrodes.

With this arrangement of the screen relative to the piezoelectric elements and the outer surface of the transducer, the parasitic electric capacitance between the electrodes of the piezoelectric element and the outer surface of the transducer sharply decreases, which leads to a significant suppression of external electrical noise (pickups), since the attenuation of the pickups in accordance with 6 when connecting an electric shield with cable ephane, one of the cable cores, called zero, and the metal case of the device, for example, an amplifier to which the converter is connected the caller is defined by the expression

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Spar - parasitic electric capacitance between the outer surface of the transducer in contact with water and the signal electrode of the active element,

SSE - electric capacitance between the signal electrode of the active element and the electric screen,

Co is the electrical capacitance between the signal and zero conductors of the converter.

The essence of the utility model is illustrated in figure 1, which schematically shows the proposed sonar transducer.

The proposed sonar transducer contains an active element consisting of four piezoelectric elements 1 made in the form of disks with electrodes on flat surfaces mounted in a cage 2 having the shape of a parallelepiped. The clip 2 is made of rubber or an elastic polymer compound and has on the outer surface of the boss 3. The clip 2 with piezoelectric elements 1 is installed in the inner cavity of the electric screen 4, made in the form of a casing of a metal foil having a box shape. The bosses 3 are designed to orient the casing 4 relative to the active elements. Technological holes 5 are made in the casing on the side surface of the normal surface of the piezoelectric electrodes for filling the inner cavity of the casing with an elastic polymer compound. In this design of the sonar transducer, the side ends of the casing are made open. The volume between the active elements and the casing is filled with an elastic polymer compound 6. The outer surface of the casing is also coated with the same compound, including from the open ends. Cable 7 is secured in a ferrule using input 8. To increase rigidity

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the input has a special sleeve 9. If the active elements have a different shape, then the shape of the casing will be different. The electric shield 4 is electrically connected to the cable shield (not shown in the drawing).

. Figure 2 shows a converter of a similar design, in which the open ends of the casing 4 are equipped with carts 10 of the same metal foil from which the casing is made.

In the manufacture of the converter, the active elements 1 and the cable 7 are installed in the holder 2. Then, an electric shield made in the form of a casing is put on the casing 4. The casing is fixed in a predetermined position due to the required number of bosses 3 of the casing 2. In this case, the casing blank can be of various shapes, for example, of two parts, interconnected mechanically and electrically after installation on a cage with active elements. The assembly of active elements with a casing and cable is installed in the casting mold. While fixing the position in the form is done by fixing the cable entry 8 in the casting form. Then, pouring is performed, and in the space between the casing and the active elements, the compound is poured through the open ends 5 of the casing 4. When the casing is made in accordance with FIG. 2 open ends 5 during the pouring process before polymerization of the compound are closed with covers made as a part of the casing bent for the time of pouring.

The proposed sonar transducer operates as follows. The hydroacoustic signal propagating in water reaching the receiver passes sequentially through the outer layer of the compound, the electric screen and the layer of compound inside the casing, acts on the active element, causing deformation of the piezoelectric elements included in it.

In this case, at the output of the active element, due to the piezoelectric effect inherent in piezoelectric elements, an electric signal arises.

The proposed sonar transducer, the design of which is shown in Fig. 1, sealed with a polyurethane compound SKU PPL 2001, containing an electric screen with two technological holes on opposite side surfaces, made of brass foil 0.05 mm thick with overall dimensions 10x10x3 cm has a leak-proof life according to the data given in 3. , about 25 years old.

For the converter shown in figure 1 with open technological holes in the screen, the screen provides suppression of external electrical noise by 60-70 dB, and for the converter shown in figure 2 with closed ends - 75-85 dB.

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Sources of information:

1. Underwater electro-acoustic transducers. Reference book Bogorodsky V.Z. et al. 1983, pp. 90-91.

2.Ananyeva A.A. Ceramic Sound Sources. M 1963, pp. 124-125.

3. R. Barrer, Diffusion in solids, M.1948, p. 28

4 .. US patent No. 5220538 for CL. H04R17 / 00

5 .. US patent No. 4700333 for CL. H04R17 / 00

6.Volin M.L. Spurious communications and interference. M. 1960, pp. 41-46.

Claims (2)

1. Hydroacoustic transducer containing an active element sealed with an elastic polymer compound made of at least one piezoelectric element, an electric screen and a cable, characterized in that the electric screen is made in the form of a casing of metal foil and is electrically connected to the cable screen in the inner cavity of the casing the active element is located out of metal foil, and on the outer surface normal to the piezoelectric electrodes, the metal foil casing has two technological holes A hole for filling with an elastic polymer compound its internal volume, located opposite each other on opposite sides of the active element, while on the outside the metal foil casing is coated with a layer of elastic polymer compound that seals the active element. 2. The hydroacoustic transducer according to claim 1, characterized in that the technological holes are arranged to overlap with foil after filling the internal volume of the casing of metal foil with elastic polymer compound.