Sealing Principle of Flat Welding Flange

The two sealing faces of the bolts squeeze the flange gasket against each other to form a seal, but this also leads to seal damage.

To maintain the seal, a huge bolt preload must be maintained, which requires the bolts to be made larger.

Larger bolts, in turn, need to be matched with larger nuts, which means bolts with larger diameters are required to facilitate nut tightening.

Flat Welding Flange

However, the larger the diameter of the Flat Welding Flange bolts, the more prone the applicable flange will be to bending. The solution is to increase the wall thickness of the flange section.

The entire assembly will consequently require a considerable size and weight, which becomes a particular problem in offshore environments, as weight is always a major concern that must be taken seriously.

Furthermore, fundamentally speaking, the Flat Welding Flange is an inefficient sealing component. It requires 50% of the bolt load to squeeze the gasket, leaving only 50% of the load to maintain the pressure.