Long ago the health community and the authorities made it sure that no factory uses the suspended chain for measuring liquids in their tanks. The suspended chain is the oldest method known to mankind ever since the factories started using tanks bigger than the human size. Suspended by a pulley on top of the tank, the chain was made lengthy enough to touch the base of the tank as it was lowered. Special markings were made on it to note the level of the liquid. As the chain touched base of the tank, it was pulled up again and the level was noted. The length of the chain that got wet by the liquid was perceived as the liquid level inside the tank.

Although this method was the cheapest and a reliable way to note the levels, it posed a great threat to the safety of the humans performing it. The chain would also contaminate the liquid inside the tank because whenever it was to be lowered down, the top had to be opened and the liquid was ... Read more »