Sacrificial anode installation method

The type, quantity, distribution and connection of sacrificial anode cathodic protection shall meet the design requirements. The sacrificial anode shall be connected to the pipe by means of a test pile to facilitate future management. If the sacrificial anode is directly connected with the pipeline, it will bring difficulties to the sacrificial anode performance measurement, pipeline outage potential measurement, leakage detection of anticorrosion coating and stray current control in the future. The anodes are distributed in protected structures, generally installed horizontally or vertically and buried under the frozen soil layer. For pipe cathodic protection, the anode is generally flush with the bottom of the pipe. When the pipeline anticorrosion layer is good, there is little difference between horizontal installation, vertical installation and whether it is close to the pipeline installation. Several anodes can be mounted in groups and connected to the pipe by test piles. When the anodes are installed in the water environment, their distribution should be as uniform as possible, and they should be welded or riveted to the protected structure.

If the anode is directly buried in the soil, due to the difference of soil composition, the corrosion of the anode itself will be intensified, and the anode consumption will be uneven. The filler can absorb and retain moisture, reduce anode grounding resistance, improve anode efficiency and ensure uniform surface consumption. The filler provides a large number of sulfate ions to generate water-soluble sulfide, and the anodic corrosion products can leave the anodic surface with water, avoiding the formation of high resistance film attached to the anodic surface.

When the connecting cable of the sacrificial anode is welded to the anode steel core, the insulation skin of the cable should be kept at least 50mm and the steel core should be bound with nylon wire or other wires to prevent the cable from breaking during transportation. The welding and anodic sections must be polished and brushed with alcohol, and then cleaned with epoxy resin or paint with the same effect and glass cloth for anti-corrosion insulation, without any metal exposed. Sacrificial anodes with welding wires shall be polished with oxide skin before wrapping, and the surface shall be cleaned before embedding without oxide film and other dirt.

Sacrificial anode can be constructed by drilling or large excavation method, and buried in vertical or horizontal mode, usually vertical mode is preferred. The embedment depth, position and spacing of sacrificial anode should meet the design requirements. When there is no stipulation in the design, the embedment depth of sacrificial anode should be below the frozen line and not less than 1.0m, the embedment position should be 3-5m away from the outer wall of the tube, and the embedment spacing should be 2-3m. The connection between the pipe and the cable must be welded securely.