JPH0454465Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an external DC power supply device used for externally powered cathodic protection.

[Conventional technology]

An external power source type cathodic protection method has been adopted as a cathodic protection method for objects to be protected such as hot water tanks, but when implementing this external power source type cathode protection method, an external DC power supply, the object to be protected, and its covering are required. If you make a mistake in connecting the anode wire that is electrically insulated and attached to the corrosion protection body and reverse the connection, the corrosion protection body will become the cathode protection anode, accelerating electrical corrosion, and there is a danger that it will lead to a major accident. .

In order to prevent the accident of reverse connection between the DC power supply for cathodic protection and the object to be protected, we take measures such as changing the shape of the connection terminal and the color of the wire, and checking with a tester. This method is promising when a specialized engineer is present during the construction, such as when a large-scale structure is being protected from corrosion.

However, when the object to be protected by cathodic protection is relatively small, such as a hot water storage tank, there are many objects to be protected, so it is not possible for a specialist engineer to be present every time. It has become common for local electricians or hot water tank builders to carry out the construction work, without having to carry out the inspection work by a person.

For this reason, at present, reverse connections are often made, and there is a risk that a major accident may develop at any time.

Utility Model Application Publication No. 57-56762 discloses a conventional technology that eliminates such dangers, allows people without specialized knowledge to easily carry out the work, and eliminates the risk of accidents even if the wires are connected in reverse. There is a technology disclosed.

In this conventional technology, a diode for blocking reverse current is connected in series to the negative terminal of a DC power supply that is directly connected to the object to be protected.If the object to be protected and the DC power supply are reversely connected, The blocking action of this diode prevents current from flowing from the DC power supply to the object to be protected.

[The problem that the idea aims to solve]

However, the above-mentioned conventional technology has the following problems.

1. Accidents caused by reverse connections can be prevented, but the desired anticorrosive effect is never achieved, and it is impossible to know that the reverse connections are being made, so the normal operation of the object to be protected is prevented. This is a problem from the point of view of achieving corrosion protection.

2 For this reason, it is necessary to determine whether or not there is a reverse connection by checking the presence or absence of current with an ammeter, but if the coating on the object to be protected is close to complete insulation, Even in the case of normal wiring, almost no current flows, so the pointer of the ammeter hardly swings, making it difficult to distinguish from reverse wiring.

3. The diode, which is the main component, is placed in a metal junction box that is directly attached to the hot water storage tank, which is the object to be protected from corrosion, so it receives heat transfer from the hot water storage tank at a high temperature of 60 to 70 degrees Celsius, so it does not deteriorate due to heat. There was a problem that this was likely to occur.

Therefore, the present invention was devised to solve the problems in the conventional technology described above, and when an external DC power supply device for externally powered cathodic protection is connected to the object to be protected, the connection is reversed. The technical challenge is to notify the operator immediately when corrosion occurs, and the purpose is to enable accurate electrical connection between the external DC power supply and the object to be protected during the connection work. do.

[Means to solve the problem]

The means in the present invention for solving the above technical problem is to have a positive terminal for corrosion protection current connected to an anode wire that is electrically insulated and attached to the object to be protected, such as a hot water storage tank. , have a negative terminal for corrosion protection current connected to the object to be protected, have a ground terminal to which the earth provided on the object to be protected is connected, and have a feed connection between this ground terminal and the negative terminal. In addition, it has a series circuit of a notification body such as a light emitting diode or a buzzer and a resistor.

[Operation] When the DC power supply and the object to be protected are properly connected, there is no potential difference between the negative terminal of the DC power supply and the earth terminal.
Therefore, no current flows through the series circuit of the notification body and the resistor, and the notification body does not operate.

On the other hand, if the positive and negative terminals of the DC power supply are reversely connected to the object to be protected,
In other words, when the positive terminal of the DC power supply is connected to the object to be protected from corrosion, the anti-corrosion current flows from the positive terminal to the object to be protected, through the ground, through the ground terminal, through the series circuit of the annunciator and the resistor, and then to the negative terminal. Therefore, the notification body is activated, and the operation of this notification body allows the worker to know that the connection between the DC power supply device and the object to be protected is reversed, and immediately corrects the connection. Fix it.

Further, since the notification body is provided in a DC power supply device installed away from the object to be protected from corrosion, such as a hot water tank, it is not adversely affected by the heat generated by the object to be protected from corrosion.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1a and 1b are explanatory diagrams of a normal connection state and a reverse connection state of the device of the present invention, in which the AC input side is omitted and only the main parts of the DC output side are shown.

In the figure, 1 is a DC power supply according to the present invention, 2 is a hot water storage tank which is an object to be protected from corrosion, 3 is an anode wire attached to the object to be protected 2 in an electrically insulated state, and 4 is an anode wire attached to the object to be protected 2. The attached earth, 5 is the positive terminal for the anticorrosion current of the DC power supply 1, 6 is the negative terminal for the anticorrosion current of the DC power supply 1, and 10 is the earth terminal of the DC power supply 1 to which the earth 4 is connected. be.

A series circuit of a light emitting diode and a resistor 8 as the notification body 7 is inserted and connected between this point B and a point A of the negative terminal 6, with the anode of the light emitting diode connected to point B of the ground terminal 10. Ru.

In addition, 9 is the drainage point.

As shown in FIG. 1a, the positive terminal 5 of the DC power supply 1 is connected to the anode wire 3, and the DC power supply 1
In a normal wiring state where the negative terminal 6 of the DC power supply 1 is directly connected to the object 2 to be protected, the negative terminal 6 of the DC power supply 1 and the ground terminal 10 have the same potential, so there is a potential difference between points B and A. does not occur, and therefore no current flows through the reverse connection detection circuit constituted by the series circuit of the indicator 7 and the resistor 8. Therefore, the indicator 7 does not operate, and the DC power supply 1 and the object to be protected 2 are connected to each other. You can see that the connection has been successfully established.

On the other hand, as shown in FIG. 1b, in a reverse connection state in which the positive terminal 5 of the DC power supply 1 is directly connected to the object to be protected and the negative terminal 6 of the DC power supply 1 is connected to the anode wire 3, The positive terminal 5 and the earth terminal 10 of the DC power supply device 1 are short-circuited via the object to be protected 2, and the earth terminal 10 has the same potential as the positive terminal 5, so that there is no connection between the earth terminal 10 and the negative terminal 6. A potential difference is generated between them, and current flows through the path indicated by the arrow line in Figure 1b to the reverse connection detection circuit, which is made up of a series circuit of the annunciator 7 and the resistor 8, so the annunciator 7 is activated. , to notify that the connection between the DC power supply device 1 and the object to be protected against corrosion 2 has become reverse connection.

The operator notices the operation of the notification body 7 and immediately reconnects the DC power supply device 1 and the object to be protected from corrosion 2 to make the connection normal.

[Effect of idea]

Since the present invention has the above-described configuration, it has the following effects.

When connecting the DC power supply and the object to be protected,
It is possible to accurately determine whether the connection is normal or reversed depending on whether the alarm is activated or not, so it is possible to accurately establish the electrical connection between the DC power supply and the object to be protected, and ensure the desired corrosion protection function. can be obtained.

Since the operation of the alarm is obtained by using the ground that connects the DC power supply and the object to be protected under certain unchanging conditions, the operation of the alarm is reliable and accurate, and the detection of reverse connection is reliable and accurate. Become something.

Since the notification body is not installed on the object to be corroded, but in the DC power supply that is installed away from the object to be corroded, it is not affected by the adverse effects of heat on the object to be corroded, and as a result, stable operation can be achieved. can.

The reverse connection detection circuit, which is made up of an annunciator and a resistor, is not connected at the construction site where assumptions and misunderstandings can easily occur, but rather at the factory where the DC power supply is manufactured, so it is extremely reliable. Obtainable.

[Brief explanation of the drawing]

Figures 1a and b show only the main parts of the DC output side of the DC power supply according to the present invention, with the AC input side omitted, and Figure 1a shows the normal connection state to the object to be protected. FIG. 1b is an explanatory diagram showing a reverse connection state to the side of the object to be corroded. Explanation of symbols, 1... DC power supply device, 2... Corrosion protected object, 3... Anode wire, 4... Earth, 5... Positive terminal, 6... Negative terminal, 7... Notification body, 8
...Resistance, 9...Drain point, 10...Earth terminal.

Claims (1)

[Scope of utility model registration request] A positive terminal 5 for a corrosion protection current is connected to an anode wire 3 which is electrically insulated and attached to an object 2 to be protected, such as a hot water tank, and a positive terminal 5 for a corrosion protection current is connected to the object 2 to be protected. It has a negative terminal 6 and a ground terminal 10 to which a ground 4 provided on the object to be protected 2 is connected, and a notification device such as a light emitting diode or a buzzer is connected between the ground terminal 10 and the negative terminal 6. A DC power supply device with a reverse connection prevention detection circuit, which is formed by connecting a series circuit of 7 and a resistor 8.