JPH0456Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to cathodic protection equipment for buried piping, buried structures, mechanical devices, port facilities, ships, etc., and is particularly applicable to corrosion protection power supply devices or The present invention relates to a potential-controlled corrosion protection device that can easily temporarily stop the operation of a drainage device.

[Prior Art] FIG. 4 shows the configuration of a conventional potential-controlled anti-corrosion power supply device and a device for temporarily stopping the anti-corrosion current. In the figure, 1 is the entire corrosion protection device, 2 is a power source, 3 is a transformer, and 4 is an SCR bridge for AC phase control. The output current from this SCR bridge 4 flows between the current-carrying electrode 6 and the buried pipe 8, which is the object to be protected from corrosion, via the current-carrying wires 5 and 7, and corrosion protection of the buried pipe 8 is realized. Reference numeral 9 denotes a potential control circuit, which detects the potential of the object to be protected 8 with respect to the potential detection reference electrode 12, compares the detected potential value with a set potential value preset in the potential setting device 10, and determines the detected potential. If the value is higher than the set potential value, the energization amount control signal 11 is sent to the AC phase control SCR bridge 4 so as to eliminate the difference.
The SCR bridge 4 controls the phase of alternating current in accordance with this control signal 11 to convert it into direct current, and adjusts the output current (corrosion protection current) flowing from the current-carrying electrode 6 to the object to be protected 8 .

By the way, in such a potential-controlled anti-corrosion power supply device, there are cases where it is desired to temporarily stop the anti-corrosion current flowing from the current-carrying electrode 6 to the object to be protected against corrosion 8 during completion measurements, interference investigations, and the like. For this reason, as shown in FIG. 4, a relay 20 is provided on the current-carrying line 5, and a timer 21 is used to turn the relay 20 on and off, thereby realizing on/off of the anticorrosion current.

[Problems to be solved by the invention] However, in a configuration in which a relay contact is used on the output side of such a power supply to temporarily stop its operation, the relay contact may be activated when turning on/off a large current. There was a problem with it burning out. Another problem is that devices for turning on and off large currents are heavy and large, making them inconvenient to carry and install.

This invention solves the above-mentioned problems with the conventional type and provides a potential-controlled cathodic protection device that can temporarily stop the corrosion protection current without using a relay to turn on/off a large current. With the goal.

[Means for Solving the Problems] In order to achieve the above object, the present invention inputs the potential of the object to be protected against a reference electrode for potential detection as an input for potential control, and In a potential-controlled corrosion protection device equipped with a potential control circuit that controls the amount of corrosion protection current flowing between the current-carrying electrode and the object to be protected, or the amount of discharge current flowing between the electric railway rail and the object to be protected, The electric potential control circuit is characterized in that the electric potential control circuit is equipped with a means for applying a voltage having a potential less base than a set potential value, which is a control reference value set in advance, to the potential control input.

[Function] According to the above configuration, a voltage less noble than a predetermined set potential value can be applied to the input of the potential control circuit. As a result, the potential control circuit temporarily stops the application of the anticorrosion current or the discharge of the drain current according to the normal control procedure.

[Example] Hereinafter, an example of the present invention will be described using the drawings.

FIG. 1 shows the configuration of a potential-controlled corrosion protection device according to an embodiment of the present invention. In the same figure, numbered 1~
Reference numeral 12 indicates a member common to the conventional example shown in FIG. Reference numeral 13 denotes a DC power source for operation control (for temporary stop of operation) at a predetermined potential, 14 an input changeover switch, and 15 a timer for turning on/off the changeover switch 14.

During normal operation, the selector switch 14 is in the illustrated position (off state), and the potential control circuit 9 detects the potential of the buried pipe (corrosion-protected object) 8 with respect to the potential detection reference electrode 12. The anticorrosion current is adjusted as in the conventional example described above.

When the timer 15 is activated at a predetermined time and the changeover switch 14 is turned on, the potential control circuit 9 and the reference electrode 1 are switched on.
2 is disconnected, and a DC power supply 13 is connected instead. That is, the potential control circuit 9 detects the potential from the DC power supply 13 instead of the reference electrode 2. The potential of this DC power supply 13 is made equivalent to a potential less base than the potential signal of the potential setting device 10 set in advance. Therefore, the potential control circuit 9 stops the output of the power supply device based on this input.

Control of such a temporary stop state in the apparatus of FIG. 1 will be explained with reference to the waveform diagram of FIG. 2. The switching waveform at the bottom of the figure is the switching waveform of the timer 15 that turns the changeover switch 14 on and off. Level 0 (in the figure and the range) indicates an off state, that is, a normal operating state,
Level 1 (the range between and in the figure) indicates an on state, that is, a paused state.

The waveform diagram in the middle part of the figure shows the input voltage of the potential control circuit 9, and shows the input voltage at the terminal 31 (reference electrode 12
FIG. 3 is a waveform diagram showing the potential of the terminal 32 (the side to which the corrosion protection object is connected) with respect to the side to which the corrosion protection body is connected. here,
It shows the potential waveform when no anticorrosive current is applied. In the range of and when the changeover switch 14 is turned off, the potential control input fluctuates at any time as shown in the figure. Changeover switch 14
When turned on, the potential control circuit 9 receives the DC power supply 1.
3 is connected, and the input voltage to the potential control circuit 9 becomes baser than the corrosion protection setting potential (target potential) set in the potential setting device 10.

The waveform diagram at the top of the figure is from the current-carrying electrode 6 to the object to be corroded 8.
The waveform of the anti-corrosion current applied to is shown. If the potential control input is nobler than the corrosion protection setting potential (in the ranges of and in the middle waveform diagram), the amount of anticorrosion current applied is controlled so that the potential control input reaches the corrosion protection setting potential. On the other hand, when the changeover switch 14 is turned on, the potential control input becomes less noble than the corrosion protection setting potential (in the range of and in the middle waveform diagram), so there is no need to flow the corrosion protection current, so this is set to 0, and the corrosion protection device is temporarily stopped. It has become a state.

FIG. 3 is a block diagram of an embodiment in which the present invention is applied to a potential-controlled drainage device. In the same figure, the first
Parts numbered the same as those in the figures indicate common members. Reference numeral 17 indicates a connection point of the electric railway rail discharge line, and 18 indicates a discharge current control transistor.

In the draining device shown in the figure, there is an input voltage switching switch 14 driven by a timer 15 on the reference electrode 12 side of the control input in the draining device. When this switch 14 is turned on, the DC power supply 13 is inserted between the reference electrode 12 and the potential control circuit 9, so the output of the power supply device is temporarily stopped based on the same criteria as the device shown in FIG. Drainage current from the electric railway tracks will also be temporarily suspended. In the configuration shown in FIG. 1, the operation control DC power supply 13 is connected in parallel to the control input of the potential control circuit 9.
In the configuration shown in FIG. 3, they are connected in series to control the discharge amount. Therefore, in the configuration of FIG. 3, the sum of the potential of the reference electrode 12 and the potential of the DC power supply 13 is input to the potential control circuit 9 from the terminal 31, and the potential value of the object to be protected 8 based on this is inputted to the potential control circuit 9. It is necessary to determine the potential of the DC power supply 13 so that the potential is less base than the preset potential signal of the potential setting device 10.

In the embodiment described above, the changeover switch 14 is turned on and off by the timer 15, but the present invention is not limited to this, and manual or remote control may also be used. Further, the changeover switch 14 and the DC power supply 13 may be provided between the object to be protected from corrosion 8 and the terminal 32.

[Effects of the invention] As explained above, in the present invention, a voltage less base than the corrosion protection setting potential can be applied to the control input of the potential-controlled anticorrosion power supply, so the power supply can be easily stopped. I can do it. Furthermore, since there are no mechanical contacts such as relays in the large current circuit, reliability is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a potential-controlled corrosion protection device according to an embodiment of the present invention, and FIG. 2 is a control input voltage, output current waveform, etc. for explaining the operation control operation of the device in FIG. 1. FIG. 3 is a configuration diagram of a potential-controlled corrosion protection device according to another embodiment of the present invention, and FIG. 4 is a diagram showing an operating state temporary stop circuit in a conventional potential-controlled corrosion protection external power supply device. FIG. 2... Power supply, 4... SCR bridge for AC phase control, 6... Current-carrying electrode, 8... Buried pipe line serving as the object to be protected from corrosion, 9... Potential control circuit, 10... Potential setting device, 12... Reference electrode for potential detection, 13...DC power supply for operation control, 14...Input selector switch, 1
5, 21...Timer, 17...Electric railway rail drainage line connection part, 18...Drainage current control transistor, 2
0...Relay.

Claims (1)

[Claims for Utility Model Registration] The potential of the object to be protected relative to a reference electrode for potential detection is input as a potential control input, and a corrosion protection current is applied between the current-carrying electrode and the object to be protected based on the potential control input. In a potential-controlled corrosion protection device equipped with a potential control circuit that controls the discharge amount or the discharge amount of discharge current between the electric railway rail and the object to be protected, a preset target is set at the potential control input of the potential control circuit. 1. A potential-controlled corrosion protection device comprising means for applying a voltage with a potential less base than a corrosion protection set potential value.