Classification, installation rules and precautions of deep well anodes

The installation depth of deep well anode is generally less than 20 meters, and the application range is generally used in the place with narrow space or high soil resistivity. The advantages of deep well anode are: there is a certain distance between the anode and the protected metal, so that the current released by the anode can be distributed evenly. It can also reduce the corrosion interference to other metal structures. Mixed metal oxide cylindrical anode and ferrosilicon anode are mostly used in deep well anode, and coke is used as landfill material.

During the installation, the anode well shall be drilled according to the construction design requirements. Firstly, some coke shall be filled in the anode well, and then the anode body shall be lowered into the well. After the installation, coke shall be filled into the well, and then water shall be poured into the anode well to make the coke fully absorb water to increase the conductivity of the anode body. Finally, the anode well shall be backfilled.

Open anode refers to filling the well without backfill. It is mainly used in the environment with very high groundwater level, which can ensure that the anode can be soaked in water all year round. The inner wall of the anode well should be protected with concrete in time during the construction, so as to prevent the collapse of the well wall due to the influence of construction or time.

The advantages of open type deep well anode are: simple installation and convenient maintenance in the future; if the linear anode is used, the installation and construction will be easier. It is very suitable for coastal areas and southern areas where the groundwater level is very high.

Closed anode refers to the use of backfill to fill the anode body in the anode well, which can reduce the grounding resistance. The installation and construction of this kind of deep well anode is very complicated, especially when the backfill is filled into the anode well, which has a great impact on the anode body. If there are problems in the construction process, it will be difficult to repair. Therefore, the factors affecting the quality of closed deep well anode are not limited to the design of cathodic protection system, the quality of anode materials and the way of coke backfilling, which are very critical in the construction process. When packing is put into anode well, in order to prevent small particles of packing floating on the water surface, resulting in large gap between fillers, deep well pump is mostly used to drive the filling slurry into the bottom of the well. This method directly improves the quality of backfill, ensures the quality of anode, and greatly reduces the construction time. The material of backfill material has also changed from metallurgical calcined coke to petroleum calcined coke.

The distance between the deep well anode and the casing is 50-300 m, and the selection of ground bed conditions is the same as that of shallow buried anode.

When installing the anode, the air duct of the anode body should be aligned first, so as to facilitate the gas discharge and avoid the phenomenon of "air resistance". At the same time, the anode body is fixed and connected with the fixing bolts. The installation method of deep well anode ground bed is basically the same as that of pipeline deep well anode body.

1. The distance between deep well anode ground bed and protected structures shall not be less than 80m;

2. The ground bed should not be located in low-lying areas, dead water areas and drainage areas;

3. The ground bed should be avoided to be located in the area polluted by harmful substances (hydrocarbons, heavy metal salts, salt water, etc.);

4. The opening position of anode well should be higher than flood level;

5. The soil layer is thick without stones, which is convenient for construction.

For areas with high soil resistivity, such as Xinjiang and other northwest regions, which are located in the inland of China, have few precipitation, dry surface and serious water shortage; when the soil environment is sand and gravel, Gobi, the soil resistivity is very high, which leads to the normal operation of cathodic protection system and accelerates the corrosion rate of pipelines.

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.