Spiral pipe insulation pipe methods wherein a process starting from the pipe wall as inhibition plus anti-corrosion coating, loop resistance can be increased, reducing the corrosion current;. External DC power supply, the steel pipe to soil caused negative potential to form a cathode protection, the potential difference between anode and cathode can be eliminated, stopped anode and cathode process fundamentally. anticorrosion coating rule table, cathodic protection of the rule of law. but once the anti-corrosion coating damage, exposed iron part will accelerate localized corrosion. therefore, anti-corrosion coating and cathodic protection is a combination of methods to rid this table, effective and economical. As stated in the United States and other countries, the use of anti-corrosion coating cathodic protection must be used at the same time.
But for city gas system, because the underground pipe network intensive, cathodic protection applied power to other pipelines interference, can cause its own benefit victims of his family situation. The use of the steel tubing is connected to the negative potential of a metal material and spiral pipe sacrificial anode law does not appear to protect such cases, therefore, city gas mains gas corrosion method should be used with the sacrificial anode corrosion coating combination. for other low pressure non-main pipeline, the anti-corrosion coating method is generally used directly .
Currently buried gas pipe insulation commonly used external anti-corrosion coating mainly three PE composite structure, epoxy powder, coal tar enamel, coal tar epoxy and PE tape and other five categories. Three PE composite structure, epoxy powder preservative excellent coating performance, which is the main European countries anticorrosion coating of buried pipelines. in our country, from the durable life, maintenance costs and other general economic factors to consider, three PE composite structure generally preferred anti-corrosion coating.
Post time: Oct-11-2019