JPH0747034Y2 - Receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a wave receiver, and more particularly to a wave receiver that converts a sound wave propagating in water into an electric signal.

[Conventional technology]

Conventionally, this type of wave receiver is provided with a rubber mold or a rubber coating for protection against mechanical damage when immersed in seawater or the like and for electrical insulation.

If you need to store the wave receiver in a limited volume such as a sonobuoy, use a wave receiver 17 with a thin rubber coating as shown in Fig. 8 to reduce the size, or vibrate. In many cases, the coating is omitted by applying an insulating coating to the child. It is suspended in the sea by a suspension cable 13 throughout.

In such a sonobuoy, etc., the float that holds the wave receiver 17 suspended in the sea moves up and down due to the waves, so vertical movement is also applied to the wave receiver, and the wave receiver moves relative speed to the surrounding seawater. To have. Even if there is a tidal current, the receiver does not flow at the same speed as the tidal current, so a relative speed is generated between the receiver and the surrounding seawater.

When the receiver has a relative velocity with the surrounding seawater, turbulence is generated around the receiver, and this turbulence causes noise.

The noise generated by the turbulence is undetectable when the sound wave to be originally detected is weak. That is, the minimum detectable sound pressure rises due to the noise sound pressure generated by the turbulence. As shown in FIG. 5, the turbulent noise is generated by the vortex 19 generated inside the turbulent layer 18, and the turbulent layer 18 is placed in the wave receiver 17 with respect to the direction of the relative flow 16. It is generated at a place along the side surface or the upper and lower surfaces of or after the receiver 17. Therefore, since the noise source is in the immediate vicinity of the wave receiver 17, the influence thereof becomes great, and the noise level may rise to 20 to 30 dB even at a relative speed of 1 knot, for example.

Since the influence of turbulence noise is great as described above, measures are often taken to prevent turbulence. For example, in order to reduce the relative speed in the vertical direction, as shown in FIG. 6, the elastic cable 21 and the damper 20 are used, and the amplitude of the vibration transmitted from the float 22 is suspended from the suspension cable 13. Wave instrument
Reductions to 17 have been made.

[Problems to be solved by the device]

The conventional receiver described above has the following features to reduce turbulent noise.
It is configured to reduce the relative speed generated by the vibration transmitted from the float or the like. However, the vibration could not be completely removed, and even if these measures were taken, turbulent noise exceeding the ambient noise was generated. As described above, in order to reduce the minimum detectable sound pressure and detect a weaker sound wave, there is a problem that the performance improvement is limited only by the conventional method.

An object of the present invention is to eliminate the above-mentioned problems and to provide a receiver capable of significantly suppressing turbulent noise.

[Means for Solving the Problems]

A wave receiver according to one aspect of the present invention includes a wave receiving element that receives underwater sound waves and converts the sound wave into an electric signal, and a coating structure of a super absorbent polymer that tightly covers the periphery of the wave receiving element. In addition, a wave receiver according to another aspect of the present invention includes a wave receiving element that receives an underwater sound wave and converts it into an electric signal, and a highly water-absorbing layer containing a super-water-absorbing polymer in close contact with the periphery of the wave-receiving element. And a coating structure for coating. Furthermore, a wave receiver according to yet another aspect of the present invention is provided with a wave receiving element that receives underwater sound waves and converts the wave into an electrical signal, and a wave receiving element surrounding the wave receiving element so as to cover the wave receiving element. In addition, it is provided with a coating material having a high permeability of the underwater acoustic wave propagation medium, and a coating structure made of a highly water-absorbent polymer filling the gap.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, and this wave receiver has a structure in which the periphery of a wave receiving element 11 is covered with a super absorbent layer 12.

Before being immersed in seawater, which is a medium for propagating sound waves in water, the superabsorbent layer 12 is a relatively thin layer. FIG. 2 shows a state of being immersed in a liquid such as seawater, and the superabsorbent layer 12 is in a swollen state and is thick. Generally, a superabsorbent polymer used in the superabsorbent layer, for example, a polyvinyl alcohol-based synthetic polymer, is about 50 g per 1 g weight.
Since it absorbs the seawater, the thickness of the highly water-absorbent layer 12 is significantly increased. Here, as the superabsorbent layer 12, not only a superabsorbent polymer alone but also a material in which a superabsorbent polymer is mixed with rubber or synthetic resin can be used.

FIG. 3 shows a second embodiment of the present invention. It has a structure in which the surroundings of the wave receiving element 11 are covered with a coating layer 14 made of a membrane or cloth permeable to seawater, and a super absorbent polymer 15 is filled between them. When this is placed in seawater, as shown in FIG. 4, the superabsorbent polymer 15 swells and the coating layer 14 swells outward as in the case of the first embodiment shown in FIG.

Thus, in both cases of the first and second embodiments,
There is a super absorbent layer of gel, rubber or synthetic resin containing a super absorbent polymer swollen with water around the wave receiving element 11, and the water absorbed in this layer follows the vibration of the wave receiving element 11. As a result, the relative speed between the superabsorbent layer and the wave receiving element 11 becomes very small.

Thus, conventionally, the boundary generated from the relative velocity between the wave receiving element 11 and the surrounding seawater is outside the superabsorbent layer, whereas the boundary is the surface of the wave receiving element 11, and the turbulent layer is generated further outside. Therefore, the noise source is generated at a place distant from the receiving element, and the noise can be significantly suppressed.

When there is a turbulent layer on the surface of the wave receiving element 11, the noise generated in the vortex 19 which is very close to the wave receiving element 17 is directly added to the wave receiving element 17 and has a large level, as shown in FIG. While showing
When the turbulent layer 18 is located at a position distant from the wave receiving element 11, noise generated by a plurality of vortices 19 located at distant positions propagates through the superabsorbent layer 12 as shown in FIG. Since it is added to the wave receiving element 11, its level is significantly reduced.

This is because this type of noise has the characteristic of being significantly attenuated as the distance increases, and there is no correlation between the individual noise sources, and these noise components are in an integrated form.

Generally, for a relative velocity of about 1 knot, the noise level emitted outside the turbulent layer is lower than the noise level generated inside the turbulent layer by 50 dB or more. Therefore, according to the present invention, the influence of noise caused by turbulence can be significantly reduced.

Further, the swollen gel of the super absorbent layer, the rubber mixed with the super absorbent polymer, or the surface of the synthetic resin is a semi-dissolved gel of super absorbent polymer. It is known that turbulence noise is further reduced by the presence of s on the surface.

Therefore, as compared with the case where the noise source is merely separated from the surface of the receiver, a receiver with extremely low noise can be realized.

Further, since the super absorbent polymer is hydrophilic, it improves water wettability, which is required for the surface of the wave receiving element and is a measure of affinity with the medium, so that the propagation medium of the underwater sound wave such as seawater and the sound wave of the wave receiving element are improved. The feature that transmission can be effectively performed is also added.

Since the super absorbent polymer swells by absorbing water, it has a small volume before absorbing water, and is extremely useful when the wave receiver must be installed in a limited space such as Sonobui. It has a simple structure. In particular, in the second embodiment shown in FIG. 3 and FIG. 4, if a material that selectively permeates only water is used as the material of the coating layer 14, in the case of seawater with respect to 1 g of the superabsorbent polymer. It can absorb about 1000g of water, while it can absorb only about 50g. Therefore, the size before absorption can be reduced, and at the same time, the super absorbent layer becomes thicker in the liquid,
An extremely low noise receiver can also be constructed.

[Effect of device]

As described above, according to the present invention, a structure having a super absorbent polymer that covers the periphery of the wave receiving element, or a super absorbent layer made of rubber or synthetic resin containing the super absorbent polymer,
Alternatively, by covering the wave receiving element with a coating layer that allows liquid to permeate, and by filling the gap with a super absorbent polymer, it is possible to reduce the effect of noise due to turbulence on the receiver. There is an effect that it can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a wave receiver according to the present invention before being immersed in water, FIG. 2 is a sectional view showing a condition after soaking of the first embodiment, and FIG. A sectional view showing a state before immersion in water of the second embodiment, FIG. 4 is a sectional view showing a state after immersion of the second embodiment, FIG. 5 is an explanatory view of turbulent noise, and FIG. 6 is conventional. FIG. 7 is an explanatory view showing a method for reducing turbulent noise, FIG. 7 is an explanatory view for reducing and suppressing turbulent noise according to the present invention, and FIG. 8 is a sectional view showing an example of a conventional receiver. 11 ... Wave receiving element, 12 ... Super absorbent layer, 13 ... Suspended cable, 14 ... Coating layer, 15 ... Super absorbent polymer, 16 ... Flow, 17 ... Wave receiver, 18 ... … Turbulent layer, 19 …… Vortex, 20 …… Damper, 21 …… Stretchable cable, 22 …… Float, 23…
… Rubber coating.

Claims (3)

[Scope of utility model registration request] 1. A wave receiver comprising: a wave receiving element that receives underwater sound waves and converts it into an electric signal; and a coating structure of a super absorbent polymer that closely coats the periphery of the wave receiving element. 2. A wave receiving element for receiving an underwater acoustic wave and converting it into an electric signal, and a coating structure for tightly covering the periphery of the wave receiving element with a superabsorbent layer containing a superabsorbent polymer. And a receiver. 3. A wave receiving element that receives underwater sound waves and converts the sound waves into an electric signal, and a wave receiving element that is arranged so as to cover the wave receiving element with a gap provided between the wave receiving element and the penetrability of the underwater sound wave propagation medium. A wave receiver comprising a high coating material and a coating structure made of a highly water-absorbent polymer filling the gap.