Summary of the invention
The present invention provides a kind of adjustable cathodic protection by rectifier system, and protection scope is big, by environmental resistivity shadowSmall, good economy performance is rung, the protective device service life is long.
In order to achieve the above object, the present invention provides a kind of adjustable cathodic protection by rectifier system, includes:
Additional power source, cathode are electrically connected protected underwater ball valve manifold, which makeesFor the cathode of additional power source；
Impressed current anode groundbed is electrically connected the anode of additional power source, the anode as additional power source.
The additional power source uses potentiostat.
The impressed current anode groundbed includes:
It is grounded steel plate, is arranged at the bottom, is electrically connected the ground terminal of additional power source；
Anode bed is arranged at the bottom, is electrically connected the anode output end of additional power source.
The anode bed using the titanium perhaps platinum plating of platinum plating the tantalum perhaps niobium of platinum plating or lead-silver anode.
The cathodic protection by rectifier system also includes reference electrode, is electrically connected the reference electrode of additional power sourceEnd, for calculating the electrode potential of tested fixed electrode.
The reference electrode is arranged at the unearthed point of protected underwater ball valve manifold, or at burying, or buriesNear point.
The reference electrode uses copper sulfate reference electrode.
The cathodic protection by rectifier system also includes multiple test piles.
The test pile includes: potential test stake, testing current stake, casing potential test pile, and insulating joint current potential is surveyedTest pile.
The present invention has the advantage that compared to the cathode protection method of sacrificial anode
1, protection scope is big；
2, it is influenced by environmental resistivity small；
3, the bigger engineering the more economical；
4, the protective device service life is long.
Specific embodiment
Below according to FIG. 1 to FIG. 2, presently preferred embodiments of the present invention is illustrated.
Cathodic protection is using metal surface each point current potential is reached unanimously, to reduce the loss of electronics to slow down metal corruptionErosion.The cathodic protection of additional power source, which refers to by buried impressed current anode, by protective current, introduces underground, is supplied to by soilIt is still cathode in the earth by protection metal, surface only occurs reduction reaction, will not lose metal again by protection metalThe oxidation reaction of ion, corrosion are suppressed.And betatopic oxidation reaction then occurs for impressed current anode surface.
As depicted in figs. 1 and 2, the present invention provides a kind of adjustable cathodic protection by rectifier system, includes:
Additional power source 1, cathode are electrically connected protected underwater ball valve manifold；
Impressed current anode groundbed 2 is electrically connected the anode of additional power source 1.
The cathodic protection by rectifier system also includes: reference electrode 3 and multiple test piles 4.
Additional power source 1 is the heart of cathodic protection by rectifier technology, and effect is incessantly to by protection metal knotStructure object provides cathodic protection current.With the development of power supply and electronic technology, the power supply of impressed current cathodic protection be experiencedThe course of dc generator, rectifier, potentiostat, what is be used widely at present is rectifier and potentiostat.In this realityIt applies in example, in order to can satisfy the Functional Requirement according to actual condition automatic regulating system, using potentiostat as additionalPower supply.Because potentiostat has constant potential, constant-current characteristic, so as to meet the function according to actual condition automatic regulating systemEnergy property requirement, therefore cathodic protection current is provided to by protection metallic structures incessantly in this as the power supply of system.
Potentiostat is integrally exactly a negative-feedback amplification output system, has two kinds of operating statuses of constant potential and constant currentIt is changeable.Potentiostat and protected object (such as buried pipeline) constitute closed loop and adjust, and the point current potential that is powered is measured by reference electrode,It is compared as sampled signal with control signal, realization controls and adjusts polarization current output, and an energization point current potential is enable to protectIt holds on the controlling potential of setting.And once constant potential goes wrong, such as interfere, reference electrode damage etc., at this moment needSwitch to constant current operating status, constant current output, that is to say, that electric current exports constant, voltage change.
1, constant potential operating status: when potentiostat is in " automatic " working condition, Setting signal (control letter in machineNumber) or external control Setting signal and the reference signal after impedance transformer is isolated be sent into comparison amplifier together, through high-precision, highThe comparison amplifier of stability compares amplification, and output error controls signal, this signal is sent into phase shift trigger, phase shift triggerAccording to the size of the signal, the phase shift time of pulse is automatically adjusted, trigger pulse adjustment is exported by pulse transformer and is polarized backThe silicon-controlled angle of flow in road changes the size of output voltage, electric current, and protection potential is made to be equal to the given current potential of setting, thusRealize constant potential protection.
2, switch to constant current operational mode: when potentiostat work constant potential state and because reference failure or it is other thereforeWhen barrier causes instrument to can not achieve constant potential control, after certain time postpones, potentiostat confirms that collected signal belongs in factConstant potential error signal out of control, will just be automatically converted to constant current working condition.It constant current Setting signal and is converted through impedanceOutput current sampling signal is sent into comparison amplifier together afterwards, and comparison amplifier output error control signal passes through phase shift triggerThe size for adjusting the silicon-controlled angle of flow makes the constant output current of instrument on preset current value.
As shown in Fig. 2, the zero-bit of potentiostat 1 is connected with cathode end by protective (underwater ball valve manifold), then byCathode of the protective as potentiostat.
As shown in Fig. 2, the impressed current anode groundbed 2 includes:
It is grounded steel plate 201, setting is electrically connected the ground terminal of potentiostat 1 at the bottom；
Anode bed 202, setting are electrically connected the anode output end of potentiostat 1 at the bottom.
Impressed current anode groundbed 2 has the function of contact of the increase anode with soil, and protective current is introduced soil from power supplyIn electric conductor.Protective current is sent into soil by impressed current anode, protected underwater ball valve manifold is flowed into through soil, makes waterLower ball valve manifold surface carries out cathodic polarization (preventing electrochemical corrosion), and electric current flows into additional power source by underwater ball valve manifold again and bearsPole forms a circuit, this primary Ioops forms an electrolytic cell, and underwater ball valve manifold is that cathode is in reduction ring in the loopIn border, prevent from corroding, and impressed current anode groundbed 2 carries out oxidation reaction and is corroded.
In the present embodiment, because surrounding enviroment are seawater, therefore anode bed 202 is mostly using the titanium of platinum plating, tantalum orNiobium, lead-silver anode monthly need the ground resistance of impressed current anode groundbed 2 of measurement.
As shown in Fig. 2, reference electrode 3 is electrically connected the reference electrode end of potentiostat 1.Reference electrode is the various electricity of measurementAs referring to the electrode compared when electrode potential, the reference electrode of measured electrode and accurately known electrode potential numerical value is constitutedBattery measures cell emf numerical value, so that it may calculate the electrode potential of tested fixed electrode.The reference electrode of potentiostat selectsThe installation site selected is at the unearthed point of protected underwater ball valve manifold, or at burying, or buries near a little, away from pipeline10cm (is powered near point).The basic demand of reference electrode is that polarization is small, stability is good, and the polarization of copper sulfate reference electrode allowsAmount is ± 10mV.
The test pile 4 includes: potential test stake, testing current stake, casing potential test pile, and insulating joint current potential is surveyedTest pile.In the present embodiment, in order to detect the cathodic protection system of service conduit, electric current and potential test are set along pipelineStake, one potential test stake of every kilometer of setting, every five kilometers set a testing current stake, and a casing electricity is arranged at each casingBit test stake, each insulation position set an insulating joint potential test stake, monthly measure a cathodic protection potential.
Workflow of the invention is as follows:
Pipeline natural potential test is first carried out before energization to be joined that is, in the case where cathodic protection is not carried out with copper sulphateThan the current potential of test pile (test pile is connect with the manifold that need to be protected) along electrode survey, current potential is generally -0.4V~-0.6V.
After the completion of natural potential test, simultaneously by given control voltage (according to field pipes actual conditions) of remote consoleIt opens the constant protection voltage of potentiostat output, after the numerical stabilities such as output voltage on dial plate to be controlled, carries out pipeline guarantorProtect potential test, i.e., in the case where applying cathodic protection, with copper sulfate reference electrode survey along test pile current potential, current potential answersIn -0.85V~-1.5V.Decision-making system works normally under constant potential operating status if data are met the requirements.
When potentiostat work is in constant potential state and because reference failure or other failures cause instrument to can not achieve permanent electricityPosition control when, through potentiostat acquisition signal be determined as constant potential it is out of control after, potentiostat automatically switches into constant current mode, afterIt is continuous to provide cathodic protection to underwater ball valve manifold.
The scope of the present invention is big, and small, good economy performance is influenced by environmental resistivity, and the protective device service life is long, main to applyThe cathodic protection of large-scale petroleum drilling-production equipment under Yu Haiyang, for example, it is underwater long range On The Oil And Gas Transportation industrial pipeline, underwater ball valve, bigType underwater storage tank group etc..
It is discussed in detail although the contents of the present invention have passed through above preferred embodiment, but it should be appreciated that above-mentionedDescription is not considered as limitation of the present invention.After those skilled in the art have read above content, for of the inventionA variety of modifications and substitutions all will be apparent.Therefore, protection scope of the present invention should be limited to the appended claims.