Why do oil tankers hang a long chain on the back?

What is a chain behind a gasoline tanker? Why do gasoline tankers have chains? Let's find the answer together!

What does the long rope behind the petrol and oil tanker mean?

When a tanker carrying gasoline or oil moves, these substances will come into contact with the dry air inside the tank. During the movement, this air will rub against the tank wall, easily causing an electric charge.

Combining both of the above conditions, when moving, oil tankers will easily experience static electricity, a phenomenon that often occurs when there is an imbalance of electrical charges on the surface of a material, which can easily cause fire or explosion.

These charges will be retained on that surface. They can be transferred to other places through electric conduction or discharge with electric sparks.

To solve the problem of static electricity, people use a chain (with high conductivity) to quickly convert these 'static' charges into electric current and transmit it to the ground to neutralize the electricity, avoiding fire and explosion.

Static electricity can occur not only when a tanker truck is moving, but also when filling a tank with fuel or vice versa. In this case, specialized equipment is used to neutralize the electricity, such as the RTR - Road Tanker Grounding (Earthing) system.

In short, it is common to see an iron chain being dragged on the ground behind a tanker during transportation. This iron chain is not superfluous but plays a very important role. The oil tanker is loaded with oil fuel (such as gasoline, kerosene, etc.). When the oil tanker moves, the oil in the vehicle will vibrate continuously. Due to the vibration, the oil will collide and rub against the wall of the oil tank. This will charge the oil tank. Because the car tire is rubber and an insulator, the charge generated in the oil tank cannot be transmitted to the ground through the tire, so the charge will accumulate, and sometimes even sparks may occur. When encountering sparks, gasoline is easy to explode. To prevent this danger, the iron chain dragged behind the vehicle is used as a conductive tool so that the generated charge cannot accumulate.