Anti-interference anode

Abstract

The utility model relates to the technical field of current drainage devices, and discloses an anti-interference anode, which comprises a low-threshold current drainage circuit with an electricity taking electrode and a sacrificial anode for providing chemical protection for a pipeline, and the low-threshold current drainage circuit comprises the electricity taking electrode capable of obtaining weak power supply voltage from the environment; the charge pump controller is used for taking microampere-level current between the electricity taking electrode and the pipeline; the MOSFET controller is used for controlling the on-off state of the MOS tube; the MOS tube Q10 is used for controlling on-off of current; the capacitor C10 is used for realizing alternating current conduction; and the diode D10 is connected in parallel with the capacitor C10 and is used for discharging current. The current drainage starting voltage threshold value is extremely low, the problem that a conventional polarity current drainage device can be started only through the voltage difference about 0.3 V between the sacrificial anode and the pipeline is solved, the driving voltage for starting current drainage of the current drainage device is reduced to be only 30 mV, even if the voltage difference between the sacrificial anode and the pipeline is smaller than 0.3 V, the current drainage device can still play a role, and the current drainage device can be used for starting the current drainage device. And the sacrificial anode can continuously output cathode protection current to carry out cathode protection on the pipeline.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of drainage device, especially utilize drainage device to reduce the influence of dynamic direct current stray current to buried pipeline, concretely is a kind of anti-interference anode. BACKGROUND

[0002] Urban rail transit system, such as subway or light rail, generally adopts direct current traction, and returns through running rail. Because the track is not completely insulated from the ground, it is inevitable that current will leak from the running rail into the ground to form stray current, which will interfere with the surrounding buried oil and gas pipelines and other metal components. This interference is constantly changing in forward and reverse directions, which is related to the change of current flow direction caused by train acceleration and deceleration. The external interference characteristic is dynamic direct current interference, that is, the direction and value of the interference are constantly changing, sometimes flowing into the pipeline and sometimes flowing out of the pipeline.

[0003] With the development of urban rail transit and oil and gas pipelines in China, the problem of buried pipelines being disturbed by dynamic direct current stray current is becoming increasingly serious. There have been many reports of corrosion cases caused by subway dynamic stray current interference at home and abroad. Dynamic direct current stray current interference not only causes corrosion of buried pipelines, but also interferes with the normal operation of the cathodic protection system. For the sacrificial anode cathodic protection system, dynamic direct current stray current interference may cause the polarity of the sacrificial anode to reverse, reduce the current efficiency of the sacrificial anode, and cause the pipeline to be ineffective.

[0004] The grounding drainage method (sacrificial anode + polarity drainage device) has been widely applied. The sacrificial anode is used as the grounding electrode, and the anode grounding resistance is not greater than 5Ω, preferably less than 1Ω. A unidirectional conduction device is installed in the connection line between the sacrificial anode and the pipeline. The stray current can only flow out of the pipeline through the sacrificial anode, and cannot flow into the pipeline in the opposite direction. If there is no unidirectional conduction device, stray current will flow into the pipeline through the sacrificial anode, which will flow out through other sacrificial anodes or damaged points of the pipeline anticorrosion layer. The corrosion will occur at the outflow site, thereby accelerating the consumption of other sacrificial anodes and the corrosion development of the pipeline.

[0005] The conventional polarity drainage device requires a voltage difference of about 0.3V between the sacrificial anode and the pipeline to start, which weakens the driving voltage of the sacrificial anode for cathodic protection and weakens the cathodic protection effect of the sacrificial anode.

[0006] In the conventional polarity drainage device (Schottky diode + capacitor + surge protector type), the Schottky diode is a metal-semiconductor device made of noble metal (gold, silver, aluminum, platinum, etc.) as the positive electrode and N-type semiconductor as the negative electrode, which utilizes the rectifying property of the potential barrier formed on the contact surface of the two to make the metal-semiconductor device. For example, Figure 4As shown. Because there are a large number of electrons in the N-type semiconductor, only a small amount of free electrons in the noble metal, so the electron from the high concentration of "N area" to the low concentration of "metal area" diffusion. With the continuous diffusion of electrons from the "N area" to the "metal area", the surface electron concentration of "N area" gradually decreases, the surface electric neutrality is destroyed, so as to form a potential barrier, the direction of the electric field is "N area"→"metal area". But under the action of the electric field, the electrons in the "metal area" also produce drift from "metal area"→"N area", thereby weakening the electric field formed by the diffusion movement. When a certain width of space charge region is established, the electron drift movement caused by the electric field and the electron diffusion movement caused by the concentration difference reach a relative balance, and the Schottky barrier is formed. The Schottky diode is a low-power super-speed semiconductor device, and the forward conduction voltage drop is about 0.3-0.4V.

[0007] By Figure 5 It can be seen that the diode has no current within the dead zone voltage. At this time, the device characteristics are in the off state. The diode is equivalent to the open circuit state, and the current limiter is not working at this time. Therefore, it can be simply analyzed that when the voltage difference between the two ends is within the dead zone voltage, the device has no current limiting effect.

[0008] At the same time, due to the forward conduction voltage drop, the calculation formula of this part of power is: P=UI, which is dissipated in the form of heat. Wherein, U is the forward voltage drop, U≈0.6V. Therefore, if the current limiting current is large, the heat power generated on the device is also increased accordingly, which has higher requirements for the heat dissipation mode of the device. The traditional polarity current limiter device often causes device damage and other problems due to overload and other reasons, and the heat exceeds the design range.

[0009] When the open circuit potential of the sacrificial anode is positive due to degradation, the voltage difference between the anode and the pipeline is less than 0.3V, and the conventional current limiter (Schottky diode + capacitor + surge protector type) cannot work, and the sacrificial anode cannot output cathode protection current, which is equivalent to passive failure of the sacrificial anode caused by the current limiter.

[0010] After searching, the patent with application number CN202121317877.5 discloses a self-powered stray current limiter, which comprises an ideal diode module, an energy collection module and a power supply module. The input end of the energy collection module is connected with the positive and negative ends of the current limiter, the input end of the power supply module is connected with the output end of the energy collection module, the output end of the power supply module is connected with the ideal diode module, the input end of the ideal diode module is connected with the positive electrode of the current limiter, and the output end of the ideal diode module is connected with the negative electrode of the current limiter. The utility model discloses a stray current limiter, which can collect and reuse the energy of stray current, and realize the function of self-powered current limiter.

[0011] The above scheme uses interference current on the pipeline to power and drive the current drain device, but it has high interference requirements for the pipeline, and needs to have great interference on the pipeline, which limits its field application, and therefore we need to provide an anti-interference anode, and the driving voltage for starting the current drain device is only 30mV, which can continue to function, and the sacrificial anode will continue to output cathodic protection current to implement cathodic protection on the pipeline. Practical new type content

[0012] The utility model discloses an anti-interference anode, and the current drain starting voltage threshold is extremely low, overcomes the problem that the conventional polarity current drain device needs to sacrifice the voltage difference between the anode and the pipeline about 0.3V to start, reduces the driving voltage of the current drain device to start the current drain to only 30mV, even if the voltage difference between the sacrificial anode and the pipeline is less than 0.3V, still can continue to function, and the sacrificial anode will continue to output cathodic protection current to implement cathodic protection on the pipeline, to solve the problem in the above background art.

[0013] To achieve the above object, the utility model provides the following technical scheme: an anti-interference anode, including low threshold current drain circuit with power taking electrode, the low threshold current drain circuit includes:

[0014] Power taking electrode can obtain weak power voltage from environment;

[0015] Charge pump controller takes microampere current between power taking electrode and pipeline;

[0016] MOSFET controller is used for controlling switch state of MOS tube;

[0017] MOS tube Q10 is used for controlling current on-off;

[0018] Capacitor C10 realizes conducting alternating current;

[0019] Diode D10 is connected in parallel with capacitor C10 and is used for current drain;

[0020] Sacrificial anode provides chemical protection for pipeline;

[0021] Charge pump controller is electrically connected with MOSFET controller, the gate of MOS tube Q10 is connected on MOSFET controller, and capacitor C10, diode D10 are connected between the source and the drain of MOS tube Q10.

[0022] Preferably, the power taking electrode is connected on the charge pump controller, the MOSFET controller, the drain of MOS tube Q10, one end of capacitor C10 and one end of diode D10 are all connected with the sacrificial anode.

[0023] Preferably, the charge pump controller, the MOSFET controller, the source of the MOS tube Q10, the other end of the capacitor C10, the other end of the diode D10 are connected with the pipeline.

[0024] Preferably, the charge pump controller comprises a common mode inductor T1, a switching triode Q1, a battery BAT, a resistor R2 is connected between the 1 pin of the common mode inductor T1 and the base of the switching triode Q1, a resistor R1 connected with the power electrode is connected to the 1 pin and the 3 pin of the common mode inductor T1, the 4 pin of the common mode inductor T1 is connected with the emitter of the switching triode Q1, and the 4 pin of the common mode inductor T1 is connected with the pipeline, and the capacitor C6 is connected between the base and the emitter of the switching triode Q1.

[0025] Preferably, the 2 pin of the common mode inductor T1 is connected with the anode of the diode D1, the diode D2, the diode D3, the diode D4, the diode D5, the diode D6 arranged in series on the wire end of the collector of the switching triode Q1, one end of the diode D6 is connected to the positive electrode of the battery BAT, and the emitter of the switching triode Q1 is connected with the negative electrode of the battery BAT.

[0026] Preferably, the wire end of the diode D1 and the diode D2 is connected with the capacitor C1, the wire end of the diode D2 and the diode D3 is connected with the capacitor C2, the wire end of the diode D3 and the diode D4 is connected with the capacitor C3, the wire end of the diode D4 and the diode D5 is connected with the capacitor C4, and the wire end of the diode D5 and the diode D6 is connected with the capacitor C5.

[0027] Preferably, one end of the capacitor C1, the capacitor C3 and the capacitor C5 is connected, and the capacitor C2 and the capacitor C4 are connected to the emitter of the switching triode Q1.

[0028] Compared with the prior art, the utility model has the advantages of:

[0029] 1. The drain starting voltage threshold of the utility model is extremely low, the problem that the conventional polarity drain needs to sacrifice the voltage difference of about 0.3V between the anode and the pipeline to start is overcome, the driving voltage of the drain starting voltage threshold is reduced to only 30mV, even if the voltage difference between the anode and the pipeline is less than 0.3V, the utility model can still continue to play a role, the anode can continue to output the cathode protection current, and the pipeline is implemented cathode protection.

[0030] 2. The utility model adopts the power electrode (such as a carbon rod) to take power from the soil as the positive electrode of the original battery, and utilizes the voltage difference of the original battery to drive the subsequent circuit, that is, the original environmental electrochemical potential is utilized, a continuous power supply can be provided in the pipeline protection application without external power supply.

[0031] 3, the utility model discloses adopt charge pump controller from the battery electricity, and provide effective operating voltage for subsequent circuit through the charge pump boost mode, can work normally under the low voltage difference and big internal resistance condition of the battery, provide sufficient drive voltage for subsequent circuit;

[0032] 4, the utility model discloses adopt low -power MOSFET controller to realize the detection and comparison to the voltage difference between the sacrificial anode and pipeline, and according to the direction of voltage difference control MOSFET switch's conduction and cut -off, thereby realize the effective control and drainage of pipeline protection current, can ensure that the pipeline is always effectively protected by the sacrificial anode. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is the circuit diagram of the utility model low threshold drainage circuit;

[0034] Figure 2 It is the circuit diagram of the utility model charge pump controller;

[0035] Figure 3 It is the drainage schematic diagram of traditional ground drainage method;

[0036] Figure 4 It is the schematic diagram of Schottky diode principle;

[0037] Figure 5 It is the schematic diagram of Schottky diode volt-ampere curve model. DETAILED DESCRIPTION

[0038] The technical scheme in the embodiments of the utility model will be described clearly and completely below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the utility model.

[0039] As Figures 1-5 The utility model provides a kind of anti-interference anode, including the low threshold drainage circuit with electricity taking electrode, and the low threshold drainage circuit includes: electricity taking electrode can obtain weak power voltage from environment, charge pump controller takes microampere level current from electricity taking electrode and pipeline, MOSFET controller for controlling the switch state of MOS tube, MOS tube Q10 for controlling current on-off, realize the condenser C10 of conduction alternating current, diode D10 for drainage in parallel with condenser C10 and the sacrificial anode for providing chemical protection for pipeline.

[0040] The core component required by the extremely low threshold drain-start voltage is an N-channel enhancement-mode MOS structure, but this component requires other electric driving, such as taking the interference current on the pipeline to drive, but if the interference on the pipeline is used to drive, it is equivalent to requiring a voltage difference of 0.3V between the pipeline and the sacrificial anode, which loses the advantage of the low threshold. Therefore, an additional electrode (power-taking electrode) is introduced, which forms a pair of stable voltage difference electrodes with the sacrificial anode for the drain-start voltage, thereby realizing the extremely low threshold start voltage of the drain-start voltage.

[0041] The charge pump controller is electrically connected with the MOSFET controller, the gate of the MOS Q10 is connected to the MOSFET controller, the capacitor C10 and the diode D10 are connected between the source and the drain of the MOS Q10.

[0042] The power-taking electrode is connected to the charge pump controller, the MOSFET controller, the drain of the MOS Q10, one end of the capacitor C10, and one end of the diode D10 are all connected with the sacrificial anode.

[0043] The charge pump controller, the MOSFET controller, the source of the MOS Q10, the other end of the capacitor C10, and the other end of the diode D10 are all connected with the pipeline.

[0044] The drain-start voltage (MOSFET + capacitor + surge protector type) of the present application utilizes an additional electrode introduced to stably supply power to the drain-start voltage, so that the drain-start voltage can play a role in draining, and the driving voltage for starting the drain is only 30mV. Even if the voltage difference between the sacrificial anode and the pipeline is less than 0.3V, the sacrificial anode can still continue to play a role, and the sacrificial anode can continue to output the cathode protection current to implement cathode protection for the pipeline.

[0045] The power-taking electrode can be a carbon rod, which can take power from the soil and serve as the positive electrode of the original battery. The carbon rod has a small volume, so the output resistance of the original battery is large, and the charge pump can take power from the electrode and the pipeline.

[0046] The charge pump controller can take microampere-level current from the power-taking electrode and the pipeline, and use the charge pump to boost and save in the internal battery BAT.

[0047] The MOSFET controller is a MOSFET driving circuit for controlling the switching state of the MOSFET. It contains a low-power comparison circuit, which outputs a positive voltage to the Vgs of the MOSFET when the potential gradient is from the pipeline to the sacrificial anode, and controls the MOS Q10 to be turned on. If the gradient direction is reversed, Vgs is discharged to 0V, and the MOS Q10 Q1 is cut off.

[0048] MOS tube Q10 is a low Vgs, low Rds (on) MOSFET tube, as a switching element, used to control the on-off of current.

[0049] Diode D10 is a Schottky diode, consistent with the working mode of MOS tube Q10, connected in parallel across the body diode of MOS tube Q10. If the charge pump controller is powered off, the diode can ensure that the current discharge device maintains certain discharge function.

[0050] The sacrificial anode is a noble metal anode, which serves as the current inflow end and provides electrochemical protection for the pipeline.

[0051] The pipeline is the metal pipeline to be protected.

[0052] The working principle of the low threshold discharge circuit is as follows:

[0053] The power supply electrode has a native voltage difference with the pipeline due to electrochemical action, forming a high output impedance primary cell.

[0054] The charge pump controller U1 takes power from the primary cell, and through the charge pump principle, the low voltage difference of the primary cell is boosted to the effective voltage that the chip can work, and is accumulated in the internal battery, providing uninterrupted work for the MOSFET controller U2 system.

[0055] The MOSFET controller U2 compares the voltage difference between the sacrificial anode and the pipeline through the internal circuit. If the voltage of the sacrificial anode is higher, the current tends to flow from the sacrificial anode to the pipeline. At this time, the MOSFET controller will discharge the gate of MOS tube Q10, so that the Vgs of MOS tube Q10 is zero, and MOS tube Q10 is cut off. Therefore, the circuit blocks the current flowing from the sacrificial anode to the pipeline.

[0056] If the voltage of the pipeline is higher, the current flows from the pipeline to the sacrificial anode at this time. The MOSFET controller will charge the gate of MOS tube Q10, so that the Vgs of MOS tube Q10 reaches the conduction threshold, and MOS tube Q10 is turned on. Therefore, the current flowing from the pipeline to the sacrificial anode will be normally discharged, ensuring that the pipeline is effectively protected by the sacrificial anode.

[0057] The charge pump controller is the key component to realize the circuit. The controller has multiple building methods, including building with existing integrated circuits and building with discrete component charge pump controllers.

[0058] It can also work normally under the condition of low voltage difference and large internal resistance of the primary cell, and output sufficient effective voltage to drive the subsequent circuit.

[0059] The charge pump controller comprises a common mode inductor T1, a switching triode Q1, a battery BAT, a resistor R2 connected between the pin 1 of the common mode inductor T1 and the base of the switching triode Q1, a resistor R1 connected between the pins 1 and 3 of the common mode inductor T1 and connected with a power electrode, the pin 4 of the common mode inductor T1 is connected with the emitter of the switching triode Q1, and the pin 4 of the common mode inductor T1 is connected with a pipeline, and the base and the emitter of the switching triode Q1 are connected with a capacitor C6.

[0060] The pins 2 of the common mode inductor T1 and the collector of the switching triode Q1 are connected with a series connection of a diode D1, a diode D2, a diode D3, a diode D4, a diode D5 and a diode D6, one end of the diode D6 is connected with the positive electrode of the battery BAT, and the emitter of the switching triode Q1 is connected with the negative electrode of the battery BAT.

[0061] The pins of the diode D1 and the diode D2 are connected with a capacitor C1, the pins of the diode D2 and the diode D3 are connected with a capacitor C2, the pins of the diode D3 and the diode D4 are connected with a capacitor C3, the pins of the diode D4 and the diode D5 are connected with a capacitor C4, and the pins of the diode D5 and the diode D6 are connected with a capacitor C5.

[0062] One end of the capacitor C1, the capacitor C3 and the capacitor C5 is connected, and the capacitor C2 and the capacitor C4 are connected with the emitter of the switching triode Q1.

[0063] The switching triode Q1 is driven by the common mode inductor T1, and a self-excitation effect can be generated at a low voltage, at this time, the collector of the switching triode Q1 can generate an alternating voltage, the alternating voltage is coupled to the capacitor C1 through the diode D1, and the charge pump effect of the capacitor C2, the capacitor C3, the capacitor C4 and the capacitor C5 generates the same voltage difference at the negative electrode of each diode. After passing through a plurality of diodes, each voltage difference is retained, and the battery BAT is charged.

[0064] Among them, the triode Q1 can also be replaced by other integrated circuit forms, and the voltage difference can be ensured. Each diode, even the capacitor, can also be packaged into the same chip in the form of an integrated circuit.

[0065] In summary, the present application has the following beneficial effects:

[0066] I. The power electrode (such as a carbon rod) is used to take power from the soil as the positive electrode of the original battery, and the voltage difference of the original battery is used to drive the subsequent circuit, that is, the original environmental electrochemical potential is used. This method can provide a continuous power supply in pipeline protection applications without external power supply.

[0067] II. The charge pump controller (including discrete components or using a dedicated IC) is used to take power from the original battery, and the charge pump is used to provide an effective working voltage for the subsequent circuit. This charge pump method can work normally under the condition of low voltage difference and large internal resistance of the original battery, and provide sufficient driving voltage for the subsequent circuit.

[0068] III. The low-power MOSFET controller is used to detect and compare the voltage difference between the sacrificial anode and the pipeline, and control the conduction and cutoff of the MOSFET switch according to the direction of the voltage difference, so as to realize effective control and discharge of the pipeline protection current. This adaptive current control method can ensure that the pipeline is always effectively protected by the sacrificial anode.

[0069] It should be noted that in addition to using carbon rods and other power supply electrodes, other forms of primary batteries or photovoltaic cells can also be used, as long as they can obtain weak power supply voltage from the environment.

[0070] In addition to the charge pump circuit built by discrete components, an integrated circuit form of charge pump controller can also be used, such as a dedicated charge pump IC. This integrated circuit solution can further reduce the size of the circuit and improve the integration level.

[0071] In addition to using a comparison circuit to detect the voltage difference and control the switching of the MOSFET, a micro-power single-chip microcomputer or other digital control circuit can also be used to achieve the same function.

[0072] The above alternative solutions, whether partial structure, device or complete technical solution, as long as they can achieve the same purpose, that is, to build an external power supply from the environment, and to control the discharge of the pipeline protection current through the detection and comparison of the voltage difference, can be used as an alternative solution of the present utility model, and should be included in the protection scope of the patent application.

[0073] Although embodiments of the present utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present utility model, and the scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. An anti-interference anode, comprising a low-threshold drain circuit with a tapping electrode and a sacrificial anode providing chemical protection for the pipeline, characterized in that, The low threshold drainage circuit includes: A power-harvesting electrode that can obtain a weak power voltage from the environment; A charge pump controller that draws microampere-level current from the electrode and the pipeline; MOSFET controller used to control the switching state of MOSFETs; MOSFET Q10 is used to control the on / off state of the current. Capacitor C10 enables AC conduction; Diode D10 is connected in parallel with capacitor C10 and is used for drainage; The charge pump controller is electrically connected to the MOSFET controller, the gate of the MOSFET Q10 is connected to the MOSFET controller, and the capacitor C10 and diode D10 are connected between the source and drain of the MOSFET Q10.

2. The anti-interference anode according to claim 1, characterized in that: The power-taking electrode is connected to the charge pump controller, and the MOSFET controller, the drain of MOSFET Q10, one end of capacitor C10, and one end of diode D10 are all connected to the sacrificial anode.

3. The anti-interference anode according to claim 1, characterized in that: The charge pump controller, MOSFET controller, the source of MOSFET Q10, the other end of capacitor C10, and the other end of diode D10 are all connected to the pipeline.

4. The anti-interference anode according to claim 1, characterized in that: The charge pump controller includes a common-mode inductor T1, a switching transistor Q1, and a battery BAT. A resistor R2 is connected between pin 1 of the common-mode inductor T1 and the base of the switching transistor Q1. Pins 1 and 3 of the common-mode inductor T1 are connected to resistors R1 connected to the power-taking electrodes. Pin 4 of the common-mode inductor T1 is connected to the emitter of the switching transistor Q1 and is also connected to a pipe. A capacitor C6 is connected between the base and emitter of the switching transistor Q1.

5. The anti-interference anode according to claim 4, characterized in that: A series of diodes D1, D2, D3, D4, D5, and D6 are connected to the terminal of common-mode inductor T1 and the collector of switching transistor Q1. One end of diode D6 is connected to the positive terminal of battery BAT, and the emitter of switching transistor Q1 is connected to the negative terminal of battery BAT.

6. The anti-interference anode according to claim 5, characterized in that: The terminals of diodes D1 and D2 are connected to capacitor C1, the terminals of diodes D2 and D3 are connected to capacitor C2, the terminals of diodes D3 and D4 are connected to capacitor C3, the terminals of diodes D4 and D5 are connected to capacitor C4, and the terminals of diodes D5 and D6 are connected to capacitor C5.

7. The anti-interference anode according to claim 6, characterized in that: One end of capacitors C1, C3, and C5 is connected, and capacitors C2 and C4 are connected to the emitter of switching transistor Q1.

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