Mesh anode is an auxiliary anode for current cathodic protection composed of precious metal oxide ribbon anode and metal connecting piece. The anode net is buried in the tank foundation to provide cathodic protection current for the tank bottom plate.
Metal hose is generally a flexible pipeline element, which is made of stainless steel, pipe body and mesh sleeve, and flange material is generally carbon steel. Metal hose has the properties of high temperature resistance, low temperature resistance and corrosion resistance, and has the advantages of light weight, good flexibility and convenient installation. At the same time, the metal hose can also alleviate the influence of thermal expansion and cold contraction.
The problems in use include: ① serious distortion of metal hose; ② The strength of the bellows is not enough, resulting in "bulge" on the surface of the pipe body; ③ The lateral displacement is too small, and the oil tank is easy to crack when sinking.
Attention should be paid when purchasing: ① select the products of manufacturers with good reputation and excellent product quality; ② If the metal hose works at high temperature, the influence of temperature on pressure shall be fully considered. The pressure shall be corrected with reference to the pressure correction coefficient table, and the manufacturer must provide the pressure correction coefficient table; ③ If flange connection is adopted, loose flange shall be adopted at one end to reduce the deformation of the hose and prolong the service life; ④ Under the same conditions, a longer metal hose shall be selected to increase the lateral displacement and axial displacement.
Attention during installation: ① check the quality of metal cathodic protection hose before installation, and solve problems in time; ② Prevent welding slag splashing on the hose and mechanical wear; ③ The installed metal hose shall not be twisted; ④ The metal hose is not allowed to bear tensile stress, and a certain degree of freedom shall be maintained; ⑤ Before the new tank farm is put into operation, the pipes and metal hoses connected to the tank must be installed after the water test is qualified.
Attention during use: ① the bellows is made of stainless steel, and the pitting corrosion of chloride ion shall be prevented during use; ② Avoid water hammer on the pipeline equipped with metal hose, especially the heavy oil pipeline. When sweeping, slowly open and close the sweeping valve. If necessary, drain the condensate in the steam before sweeping; ③ For the sake of safety, do not artificially cause pressure holding at the metal hose to avoid danger; ④ The hose distortion and deformation caused by uneven settlement of oil tank shall be handled properly in time; ⑤ Check the metal hose regularly; ⑥ Find problems and deal with them in time.