JPH022038B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antifouling device for seawater pipes that uses ultrasonic waves to prevent marine fouling organisms such as barnacles and sea lettuce from adhering to seawater pipes of ships, etc. The present invention relates to an antifouling device for a seawater pipe in which a group of ultrasonic transducers are mounted on a pipe wall in a spiral manner at appropriate intervals in order to enhance the fouling effect, particularly in the axial direction of the seawater pipe.

Conventional ultrasonic antifouling equipment for seawater pipes uses high-output or multiple ultrasonic transducers installed in one location, so in order to extend the effective antifouling distance, it is necessary to increase the number of transducers. The output per vibrator increases, and the sound pressure near the vibrator group becomes higher than necessary. As a result, the vibrator itself was often damaged, and the pipe wall that was supposed to be protected was also damaged, making it economically unprofitable and lacking in reliability. In order to compensate for this drawback, a structure was considered in which groups of transducers were placed side by side at several locations in the axial direction of the seawater pipe to extend the effective distance.
This was not effective due to mutual interference between the oscillator groups.

The present invention was made in order to eliminate the drawbacks of the above-mentioned conventional devices. (where n is an integer and is selected by considering the radiation pattern of the transducer and the shape of the tube.) The transducer is attached to the tube wall in a spiral shape at required intervals at an angle of The present invention aims to provide an antifouling device for seawater pipes using ultrasonic waves equipped with multiple vibrators that can effectively prevent the adhesion of marine organisms over a wide range by continuously exciting the ultrasonic wave.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an ultrasonic seawater pipe antifouling device equipped with multiple transducers according to the present invention (an example of a triple-equipped system) will be described with reference to the drawings.

FIGS. 1 and 2 show a structure for attaching an ultrasonic transducer to a seawater pipe in an embodiment, and FIG. 3 shows an electrical configuration when the ultrasonic transducer is sequentially switched and excited. In these figures, seawater pipe 1 is connected to ship grain 9.
The seawater pipe 1 has a seawater intake port 2 that opens into a sea chest provided in the sea est, and a first ultrasonic transducer 3, a first ultrasonic transducer 3,
A second ultrasonic transducer 4 and a third ultrasonic transducer 5 are arranged. In this case, each vibrator is at an angle θ (0<θ≦30°) with respect to the pipe axis of the seawater pipe 1.
The oscillator excitation circuit shown in FIG. Connected. In addition, the vibrator holding cylinder 6
A watertight lid 8 for cleaning the vibrator is provided on the rear end surface for maintenance.

The first, second, and third ultrasonic transducers 3, 4, and 5 are arranged in a spiral shape on the tube wall at required intervals (nearly half the maximum effective distance in the case of one transducer and an odd multiple of a half wavelength). It is designed to effectively combine the radiation patterns of each vibrator. For example, when the nominal frequency of each transducer is 28 kHz, the inclination angle (θ) with respect to the tube axis direction is 30 degrees, and the nominal diameter of the seawater pipe 1 is 100, the first ultrasonic transducer closest to the seawater intake port 2 3, the second ultrasonic transducer 4
are 325 mm apart in the tube axis direction and in the tube circumferential direction.
The third ultrasonic transducer 5 is located at a rotated position of 120° (when N=3, n=1), and the third ultrasonic transducer 5 is further rotated in the tube axis direction.
It is located 325mm apart and rotated 120° in the circumferential direction.
In addition, the inclination angle (θ) of each vibrator with respect to the tube axis direction
The smaller the value, the longer the effective distance will be, but the structure of the vibrator holding tube 6 etc. will be troublesome, so it is not practical.
It is set at 30°.

The configuration of a vibrator excitation circuit for driving each of the vibrators is shown in FIG. In this figure, a high frequency oscillator 10 generates a stable high frequency and applies it to a repetition period setting circuit 11.
divides the oscillation output of the oscillator 10 to create a square wave with an arbitrary repetition period (set to 1 to 0.01 seconds in this case), and applies it to the ternary counter 12. The output of this ternary counter 12 is applied to a shift register 14 via a changeover switch 13. On the other hand, 28kHz
The oscillation output of the low frequency oscillator 15 is transmitted to the power amplifier 16.
This power amplifier 1 is amplified to the required power by
The output of 6 is the first ultrasonic transducer 3 and gate 17A.
A series circuit with the second ultrasonic transducer 4 and the gate 17
B and the series circuit between the third ultrasonic transducer 5 and the gate 17C.

In the configuration of the above embodiment, if the changeover switch 13 of the resonator excitation circuit is in the state a as shown in FIG. This is input into the shift register 14 and shifted sequentially, so gate 17A and gate 1
Gates 7B, 17C, and so on are turned on in this order.
As a result, the first, second and third ultrasonic transducers 3,
4 and 5 are sequentially switched and excited. The excitation time of each vibrator is set to an appropriate value depending on the pipe diameter, flow velocity in the pipe, and the number of vibrators installed, e.g.
It is set to 0.1 seconds etc. In addition, the changeover switch 13
If is in state b, the output of the ternary counter 12 will be a square wave with a duty cycle of 1/2, so
When one vibrator fails, the other two can be excited in sequence.

According to the above embodiment, the ultrasonic waves are sequentially radiated into the seawater pipe 1 from the ultrasonic transducers at different positions arranged in a spiral, so that it is possible to cause effective damage to marine organisms over a wide range. can. Furthermore, because of the sequential excitation, there is no interference in the radiation pattern, and the output of the power amplifier only needs to be the nominal output of the vibrator, so it has the advantage of higher efficiency than the conventional case. For example, conventionally, the excitation power is the product of the number of transducers and the nominal output of the transducers, so a fairly large amount of power is required, but in this embodiment, only the nominal output of the transducers is required (for example, a small (approximately 60W), it is extremely economical. Furthermore, if the frequency division ratio of the repetition period setting circuit 11 is appropriately selected, one oscillator 10 and 15 can be used in common.

Note that when each vibrator is excited at the same time, radiation pattern interference occurs, but by using vibrators with sufficiently different nominal frequencies and equipping them with corresponding oscillators 15 in parallel, the negative effects of standing waves can be significantly reduced. Since this can be avoided, this case is also sufficiently practical. However, the excitation power in this case remains the same as before.

As described above, according to the present invention, ultrasonic transducers are attached to the wall of a seawater pipe in a spiral manner at required intervals, and each transducer is sequentially switched or continuously excited at different frequencies, thereby generating ultrasonic waves in the ocean. It is possible to obtain an antifouling device for seawater pipes using ultrasonic waves equipped with multiple vibrators that can effectively prevent the attachment of fouling organisms over a wide range.

[Brief explanation of drawings]

Fig. 1 is a front view showing the overall configuration of an ultrasonic seawater pipe antifouling device equipped with multiple transducers according to the present invention, Fig. 2 is a side view of the same, and Fig. 3 is a system of the transducer excitation circuit. It is a diagram. 1...Seawater pipe, 2...Seawater intake, 3, 4, 5
...Ultrasonic transducer, 6... Transducer holding cylinder, 7...
Vibrator excitation wire, 8...Watertight lid for vibrator maintenance, 9
... Ship grain, 10 ... High frequency oscillator, 11 ... Repetition period setting circuit, 12 ... Ternary counter, 13 ...
...Selector switch, 14...Shift register, 15
...Low frequency oscillator, 16...Power amplifier, 17
A, 17B, 17C...Gate.

Claims (1)

[Claims] 1. A vibrator holding cylinder that protrudes outward from the seawater pipe at an acute angle with respect to the pipe axis of the seawater pipe is shifted by a predetermined angle in the circumferential direction of the seawater pipe and by a predetermined distance in the pipe axis direction, and then spirally A plurality of ultrasonic transducers are arranged in a shape, and an ultrasonic transducer is attached in each transducer holding cylinder, and these ultrasonic transducers in a spiral arrangement are sequentially switched or, in the case of different frequencies, continuously excited and emitted into the seawater pipe. An antifouling device for seawater pipes using ultrasonic waves equipped with multiple transducers, characterized in that the antifouling effect of the seawater pipes is enhanced by reducing the adhesion ability of marine fouling organisms by combining ultrasonic patterns. .