JPH0733591B2 - Electrolytic corrosion prevention device for water intake groove fittings - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic corrosion prevention device for a water intake groove fitting attached to an intake groove inlet for utilizing seawater in a thermal power plant, a nuclear power plant or the like.

[0002]

2. Description of the Related Art In a thermal power plant, a nuclear power plant, etc., seawater is used as a cooling water for a generator or the like by a pump from a water intake ditch installed so as to guide it from the coast to the inside of the power plant. In order to remove foreign matters floating on the sea, such a water intake groove inlet is generally provided with a fence-shaped water intake metal fitting.

Since the water intake groove fitting is usually made of iron and corrodes due to long-term exposure to seawater or the like, which causes rust, a rust preventive paint is applied or a low potential metal piece such as a zinc piece is applied. Corrosion is prevented by providing an electrolytic corrosion prevention means that is provided nearby and uses the potential difference between the two metals.

[0004]

By the way, the above-mentioned means for preventing galvanic corrosion by means of zinc pieces and the like can maintain an anode potential of -1.0 V inside or outside by using high-purity zinc, and thus can prevent corrosion of steel. Since it has an effective voltage of approximately 0.25 V with respect to the potential, a sufficient corrosion protection current can be generated in the sea within the range where the corrosion protection current of each zinc piece reaches.

However, in the method in which zinc pieces are simply attached to the sea by bolts, the amount of each individual zinc piece is small, so the zinc will disappear in about half a year, and zinc will be attached in the sea to attach and replenish zinc again. It is not only extremely annoying but also sometimes forgotten. Further, when zinc is consumed, the anticorrosion potential is lowered and the anticorrosion effect becomes insufficient.

[0006] In the sea, seaweed, shells and the like adhere to the intake groove metal fittings for a long period of time, and if they adhere, they may cause rusting and hinder the flow of seawater, making the appearance unsightly. Conventionally, in order to prevent these deposits from adhering, a method has been generally adopted in which a component that dislikes deposits is mixed into a rust-preventive paint and applied. However, since such a paint is quite toxic, its use is restricted from the viewpoint of environmental protection.

In the present invention, while paying attention to the problems of the above-mentioned conventional electrolytic corrosion preventing means, an external power supply type cathode corrosion preventing method is applied for the corrosion prevention of the water groove metal fitting, instead of the conventional galvanic anode type, A water intake groove metal fitting that is adjacent to the metal fitting and has an anode support frame that supports the low-potential metal body piece, has a sufficient and wide range to prevent electrolytic corrosion, and facilitates the refilling work of the metal body piece to reduce the total cost. An object of the present invention is to provide a device for preventing electrolytic corrosion.

Further, according to the present invention, an ultrasonic antifouling device is provided in addition to the above-mentioned electrolytic corrosion preventing device to prevent the adhered substances such as seaweed and shells from adhering to the outer fitting and to prevent the rust caused by these adhered substances. The second object is to provide an electrolytic corrosion prevention device capable of preventing the occurrence of the above.

[0009]

As a means for solving the above problems, the present invention is to install an anode support frame at a position below the sea level at high tide, adjacent to a water intake groove fitting attached to an intake groove entrance near the quay. A plurality of low-potential metal bodies are detachably supported in the support frame, and a power source is provided at an appropriate position to
The side terminal is connected to the metal piece, and the negative side terminal is connected to the water groove metal fitting so as to hold the metal fitting at a desired corrosion protection potential.

In this case, a metal plate is attached to the support frame adjacent to the support frame and an ultrasonic vibrating body is provided on the support frame, and an ultrasonic antifouling device for generating ultrasonic waves by a voltage from a power source is also provided. It can also be one.

[0011]

According to the electrolytic corrosion preventing apparatus of the present invention having the above-described structure, when a voltage of, for example, about +1.0 V is applied to the metal body piece from the power source to cause an electrolytic corrosion current to flow, the metal body piece is subjected to the cathode corrosion prevention method. And serves as an anode in the cathode protection function. Generally, maintaining an anode potential of about -1.0 V with respect to a steel material is said to have a sufficient anticorrosion effect. If this is maintained at a higher potential, the anticorrosion region will be widened and the local battery action will be reduced. As a result, a sufficient anticorrosion effect can be obtained for the water intake groove fitting.

When the electrolytic corrosion current is continuously maintained, the metal piece is electrolytically corroded and consumed. But,
In the electrolytic corrosion prevention apparatus of the present invention, since the metal body pieces are only put into the anode support frame, the number of metal body pieces can be increased to maintain the electrolytic corrosion prevention effect for a longer period of time, and the consumed metal When the piece becomes smaller, an additional metal piece may be put into the support frame, the refilling work becomes extremely easy, and the cost can be reduced.

When an ultrasonic antifouling device is also provided, a pulse voltage is applied from a power source to generate pulsed ultrasonic waves, and a sufficient antifouling effect can be exerted on a wide range. As a result, it is possible to prevent the adhered matter such as seaweed and shells from being attached, and also to prevent the occurrence of rust on the water intake groove fitting.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic diagram in which the electrolytic corrosion prevention device of the embodiment is grounded at the inlet of a water intake groove of a power plant. An anode support frame 2 is provided at a mounting position below the sea surface adjacent to the water intake groove metal fitting 1 at the inlet of the sea water intake groove. The anode support frame 2 is formed in a cage shape by using a rod or frame 3, and is attached to the quay wall by an appropriate supporting means 4 such as a bolt. A plurality of low-potential metal pieces 5 are put in the support frame 2.
G is a generator and P is a pump.

The metal piece 5 has a lower potential than the steel material of the water intake groove fitting, and may be, for example, a zinc plate. Then, these metal pieces 5 are inserted at an angle so as to contact each other,
A supporting rod 6 attached to the supporting frame 2 at an appropriate position is also brought into contact therewith, and an electric wire connecting terminal 7 is provided at the end of the supporting rod 6. The bottom portion of the support frame 2 is preferably formed of, for example, a small mesh member so that the metal piece 5 does not drop even if the metal piece 5 is consumed and becomes small. A power supply device 10 is provided at an appropriate position in the power plant. Although not shown,
As is well known, a DC power source is sent from an AC power source, and its + side terminal 11 is connected to the terminal 7 of the anode support frame 2 by a cord. The negative terminal 12 is connected to the water intake groove fitting 1. The power supply device 10 continuously applies a voltage of about +1.0 V to the metal piece 5.

In the illustrated example, the support frame 2, the metal piece 5 and the like are provided at only one place, but they may be provided at a plurality of places if necessary. Further, the power supply device 10 may use a rechargeable battery.

With the above-described grounded electrolytic corrosion preventing device, the electrolytic corrosion of the water intake groove fitting is prevented as follows. A voltage of about +1.0 V is applied from the power supply device 10 to cause an electrolytic corrosion current to flow through the metal piece 5. In general, the steel material of the water intake groove metal fitting has a galvanic corrosion potential of about -1.0 V, so that the local galvanic corrosion disappears and the corresponding portion of the front surface of the outer plate has the same electric potential, so that the corrosion prevention effect can be obtained. If the electrolytic potential is higher than this, it can be brought into the passive region.

The metal pieces 5 are placed in the support frame 2 so that a plurality of metal pieces 5 contact each other. Therefore, the metal pieces 5 are electrically connected to each other and an electrolytic corrosion current flows. Since this metal piece 5 becomes the anode electrode of the cathodic protection method,
When used for a long time, metal atoms flow out little by little and are consumed.

However, even if the metal piece 5 is consumed, in this electrolytic corrosion prevention device, the same metal piece 5 need only be additionally charged into the support frame 2, and therefore the replenishment work is extremely simple.

Next, in this embodiment, an ultrasonic antifouling device is provided. In this antifouling device, an ultrasonic vibrator 21 is attached at an appropriate position adjacent to the water intake groove fitting 1, and the power supply device 2
When a voltage is applied from 2, the vibrator 21 emits ultrasonic waves. The power supply voltage is converted into a pulsed voltage from a predetermined AC frequency and applied, and the vibrator vibrates according to the fluctuation of the pulse voltage, whereby pulsed ultrasonic waves are generated.

An example in which four vibrators 21 are provided is shown, but the number is arbitrary. Further, the applied pulse voltage is made as large as possible to widen the propagation area to the periphery. However, if it is made too large, the cavitation due to ultrasonic waves will be so large as to have an adverse effect, so the value should be within that limit.

When such an ultrasonic antifouling device is used to generate ultrasonic waves, the deposits adhering to the water intake groove metal fittings in the transmission area are removed by ultrasonic vibrations, and therefore, if ultrasonic waves are continuously generated, the intake water is removed. It is possible to prevent adhered substances such as seaweed and shells from attaching to the groove fitting 1.

When the attachment of the adhered matter is prevented by the antifouling device, it is possible to prevent the rust or the like from being generated at the adhered site due to the chemical reaction with the organism because the adhered matter adheres for a long time. It also serves as an anticorrosion device.

[0024]

As described above in detail, the electrolytic corrosion prevention apparatus of the present invention is installed below the sea surface adjacent to the water intake groove metal fitting at the water intake groove inlet, and a plurality of low potential metal pieces are thrown into the anode support frame. Since it is configured to flow a + potential anticorrosion current from the power supply device inside the ship, it has a very simple structure and has a wide range of anticorrosion effects. There is an advantage that a low-cost electrolytic corrosion prevention device that can be performed can be obtained.

When an ultrasonic antifouling device is installed side by side,
It is possible to prevent deposits from adhering to the water intake metal fittings by ultrasonic waves and maintain the external appearance, and at the same time to prevent the occurrence of rust due to local electrolytic corrosion due to biological reactions caused by deposits. The effect is that it can also be prevented.

[Brief description of drawings]

FIG. 1 is a schematic view of an electrolytic corrosion prevention device and an ultrasonic antifouling device according to an embodiment.

[Fig. 2] Outline drawing of anode support frame

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water intake groove metal fitting 2 Anode support frame 3 Rod or frame 4 Support means 5 Low-potential metal piece 6 Support rod 7 Connection terminal 10 Power supply device

Claims (2)

[Claims] 1. An anode support frame is attached to a position below the sea surface at high tide adjacent to a water intake groove fitting attached to an intake groove entrance near the quay, and a plurality of low-potential metal bodies are detachably supported in the support frame. Then, a power supply is provided at an appropriate position, the + side terminal is connected to the metal piece, and the − side terminal is connected to the water groove metal fitting so as to hold the metal fitting at a required corrosion-proof potential. Electrolytic corrosion prevention device. 2. An ultrasonic antifouling device for generating an ultrasonic wave according to a voltage from a power source, which is provided with a metal plate adjacent to a supporting frame and is provided with the metal plate adjacent to the support frame. The electrolytic corrosion prevention device for a water intake groove fitting according to claim 1, wherein: