Sacrificial anode system

The tank is protected by a sacrific anode system that is easy to install and does not cause corrosion interference, but will not be adequately protected unless the tank is well insulated from piping and other systems. Other systems include pipe networks, instrument connections, cable bushing, concrete reinforcement, and tank group grounding systems. Insulation of so many parts is not only expensive, but also expensive to maintain later, so the system is often ineffective.

The driving voltage of sacrificial anode system is generally less than 0.7V, which limits the current output of cathodic protection system. Once the storage tank is short-circuited with any of the above parts, it will not only make the tank difficult to achieve protection, but also make the sacrificial anode system quickly exhausted, and the protection life is short.

Two, deep well anode system

The system is mainly used in the built storage tank, especially in the area with small space. Its disadvantage is that the cathodic protection current is not uniform, and some areas cannot be protected. Easy to produce corrosion interference. The anode is subject to premature damage under very harsh working conditions.

Three, flexible anode system

The anode is made of conductive rubber coated on the outside of the cable, and the rubber is wrapped with a layer of carbon powder packing. The system can be laid under the bottom plate of the storage tank. The current distribution is uniform, and it is not easy to produce corrosion interference, but it has the following disadvantages:

1. The transportation and installation costs of the system are higher than that of the network anode system, and each plate anode is very heavy. Increased the difficulty and cost of handling.

2, packing belt is easy to destroy, resulting in packing loss, need to fill later.

3. Due to the conductive rubber under the action of current, it is easy to age and crack with the passage of time, leading to the rapid corrosion of copper core cable, resulting in premature failure of the system. The system must not be bent too much.

4, the site needs a lot of cable connection, quality is difficult to guarantee.

Therefore, the network anode cathodic protection is the most reliable way at present. In this way, there is no need to use the anticorrosive layer on the outside of the tank bottom plate, which will save a lot of money. If only anticorrosive layer is used without cathodic protection, the coating on the weld will inevitably be destroyed, forming a large cathode and a small anode, which will inevitably accelerate the corrosion and perforation speed of the storage tank. Therefore, it is economical and reasonable to apply cathodic protection to the storage tank.