The principle and characteristics of flat welding flanges

This problem about flat welding flanges has always been a topic of concern. It is related to the production costs or economic benefits of companies and enterprises. Therefore, the sealing principle of flat welding flanges is constantly improving and perfecting.

However, the main design disadvantage of flat welded flanges is that they are not guaranteed to be leak free. This is the design flaw: the connection is dynamic, and cyclic loads such as thermal expansion and undulations cause movement between the flange faces, affecting the function of the flange, thereby impairing the integrity of the flange and ultimately leakage. No product can be free from defects, just try to control the product to the least, so the company should try to improve the performance of the product when producing flat welding flange, so that it can play its biggest role.

Features of flat welding flange: Flat welding flange not only saves space, reduces weight, but more importantly ensures that joints will not leak and has good sealing performance. The reduced size of the compact flange is due to the reduced diameter of the seal which will reduce the cross-section of the seal face. Secondly, the flange gasket has been replaced by a sealing ring to ensure that the seal faces the sealing surface. In this way, only a small amount of pressure is required in order to press the cover tightly. As the required pressure is reduced, the size and required number of bolts can be reduced accordingly, so a new design that is small in size and light in weight (70% to 80% lighter than conventional flanges) is designed. product. Therefore, the flat welding flange type is a relatively high quality flange product, which reduces the quality and space and plays an important role in industrial use.

Sealing principle of flat welding flange: The two sealing faces of the bolt press each other to form a seal, but this also causes damage to the seal. In order to maintain the seal, it is necessary to maintain a huge bolt force, for which the bolt is made larger. Larger bolts are matched to larger nuts, which means that larger diameter bolts are needed to create the conditions for tightening the nuts. However, the larger the diameter of the bolt, the more suitable the flange becomes, the only way to increase the wall thickness of the flange. The entire device will require a great size and weight, which becomes a special problem in the offshore environment, because weight is always a major concern for people in this situation. Moreover, fundamentally, the flat weld flange is an ineffective seal that requires 50% of the bolt load to be used to squeeze the gasket, while the load used to maintain the pressure is only 50%.

Source: China Stainless Steel Flanges Manufacturer - Yaang Pipe Industry Co., Limited (www.yaang.com)