Cathodic protection is a conventional method for corrosion control of buried pipelines, which usually has two implementation paths. One is to connect the pipeline with the negative pole of the DC current source, and use the external protection current to polarize the cathode of the pipeline body. This method is called external current cathodic protection. The other is to connect the negative potential metal (such as zinc and magnesium) on the pipeline as anode to form a large battery with the pipeline in the electrolyte, so that the cathodic polarization of the pipeline body can reach the state of no corrosion. This method is called sacrificial anode protection.
In the daily operation and management of pipelines, the conventional method to measure the operating state of cathodic protection is to measure the pipeline grounding potential with a multimeter and a reference electrode. However, in the corrosion detection engineering, due to the influence of IR drop and the limitation of test pile position, it is necessary to measure the breaking potential of the whole pipeline. The detection instrument used is close spaced potential detector. This method can not only measure the protection potential at any position, but also eliminate the influence of infrared radiation.
Cathodic protection is an electrochemical technology. The principle is to apply external current on the surface of the corroded metal structure to make the protected structure become the cathode, so as to inhibit the electron migration of metal corrosion and avoid or weaken the corrosion. Cathodic protection has been widely used in many fields. It usually consists of a power transformer and a bridge rectifier. The voltage of cathodic protection is adjustable and the power load is large. Results the AC 220 V power supply is DC. Through the transformer and rectifier circuit, the negative metal sheath is connected, and the positive electrode is connected to the ground to ensure that the cable sheath keeps a proper negative potential to the ground, so the metal sheathed cable is not easy to be corroded.
The anticorrosion of buried steel pipeline is always the pipeline itself. There are many factors affecting pipeline corrosion, and the mechanism is complex, and there are constraints among the factors. Detection and evaluation of the corrosion and protection of buried steel pipeline, different detection methods and equipment design and various testing technology requirements, the unit engaged in the project has a strong technical ability, in all aspects of technical personnel and equipment, the owner unit more urgent investment. In addition, due to the limitation of current technology development level, such as the detection of residual wall thickness of pipe body, excavation detection is also needed. In addition to the high cost, it is bound to have a certain adverse impact on the pipeline.
Shandong Linyi Bosi conductive materials Co., Ltd. is a high-tech enterprise specializing in the production of MMO flexible anode, conductive polymer flexible anode and titanium coated anode, mainly providing cathodic protection technology, engineering design, installation and technical services.
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