What are the common sealing methods of vertical floating roof tank

The seal of floating roof tank is a kind of device which can reduce the evaporation loss of storage liquid in the annular space between the tank wall and the outer ring plate of the floating roof. The common sealing forms include mechanical seal, elastic filling seal, lip seal and the secondary seal. No matter which sealing form, the seal must be combined with floating roof effectively to reduce the evaporation loss of the floating roof storage fluid.

1. Mechanical seal
The mechanical seal relies on the mechanical force to press the sealing steel plate tightly against the tank wall, so that it can slide on the tank wall, and try not to produce a gap. However, the mechanical seal has high requirements on the geometry of the tank and poor adaptability, so it is rarely used by the new floating roof tank at present.

2. Elastic filling seal
The elastic filling seal is to fill the elastic and changeable object in the sealed envelope, and the purpose of sealing depends on the compression deformation of the filler. This kind of sealing effect is better, the requirement of tank wall geometry is not too high, and the adaptability is strong. But this kind of seal has poor wear resistance and is easy to deform and damage after long-term use.

3. Lip seal
The sealing function depends on the sliding contact between the elastic lip and the tank wall. This kind of sealing has strong applicability, but the manufacturing process and material selection are required to be high. At the same time, there is also the problem of elastic sealing.

4. Secondary seal
The secondary seal is to add a seal on the basis of the primary seal. The experiment shows that the secondary seal can reduce the liquid consumption by more than 50%, and has a more significant effect in terms of safety.