Introduction to flat welding flange

Features of flat welding flange: flat welding flange not only saves space and weight, but also ensures no leakage at the joint and has good sealing performance. The compact flange size is reduced because the diameter of the seal is reduced, which will reduce the section of the sealing surface. Secondly, the flange gasket has been replaced by the sealing ring to ensure that the sealing face matches the sealing face. In this way, only a small amount of pressure is required to compress the sealing surface. With the reduction of the required pressure, the size and number of bolts can be reduced accordingly, so a new product with small volume and light weight (70%~80% less than the weight of the traditional flange) has been designed. Therefore, flat welding flange is a relatively good flange product, which reduces the mass and space and plays an important role in industrial use.

The main design disadvantage of flat welding flange is that it cannot guarantee no leakage. This is the disadvantage of its design: the connection is dynamic, and such as thermal expansion and fluctuating periodic load will cause movement between flange faces, affect the function of the flange, thus damaging the integrity of the flange and causing leakage. It is impossible for any product to be free of defects, but only to control the deficiencies of the product as much as possible. Therefore, the company tries to improve the performance of the product when producing flat welding flanges, so that it can play a greater role.

Sealing principle of flat welding flange: the two sealing surfaces of the bolt extrude the flange gasket and form a seal, but this also leads to the destruction of the seal. In order to maintain the seal, it is necessary to maintain a huge bolt force, for which the bolt must be made larger. Larger bolts need to match larger nuts, which means larger bolts need to create conditions for tightening nuts. However, the larger the bolt diameter is, the applicable flange will become bent. The method is to increase the wall thickness of the flange. The whole unit will require relatively large size and weight, which has become a special problem in offshore environment, because weight is always a major concern. Moreover, fundamentally speaking, the flat welding flange is an invalid seal. It needs to use 50% of the bolt load to extrude the gasket, while only 50% of the load is used to maintain the pressure.