The problem about the flange has been a topic of concern, it is related to the company and the production cost of enterprises or economic benefits and other issues, so the sealing principle on flange in continuous improvement and perfect.
However, the main disadvantage of design of flange is that it can not guarantee no leakage. This is the design defect: the connection is dynamic, and thermal expansion and fluctuating periodic load will cause the movement between the flange surfaces, which will affect the flange's function, so that the integrity of the flange will be damaged, and eventually lead to leakage. Any product can not be without flaws, just try to control the shortage of products to a minimum, so the company in the production of flange to improve product performance, make it play the biggest role.
The characteristics of flange:
Flange not only saves space, reduces the weight, the more important is to ensure that the joints do not leak, has good sealing performance. The size of the compact flange is reduced because of the reduction in the diameter of the seal, which will reduce the cross section of the sealing surface. Secondly, the flange gasket has been replaced by the sealing ring to ensure that the seal is matched to the seal face. In this way, only small pressure is needed to press the sealing surface. With the decrease of required pressure, the size and quantity of bolts can be reduced correspondingly, so a new product with small volume and light weight (70% to 80% weight) is designed. Therefore, a relatively flat welding flange flange high-quality products, reducing the quality and space, which plays an important role for industrial use.
The sealing principle: two flange bolts each other extrusion flange sealing surface and form a seal gasket, but it will also lead to seal damage. In order to maintain the seal, it is necessary to maintain a huge bolt force, so that the bolts should be done more. The bigger bolts need to match the larger nuts, which means that a bigger bolt is required to create conditions for the tightened nut. However, the larger the diameter of the bolt, the applicable flange will become curved, the only way is to increase the thickness of the flange part. The whole device will require huge size and weight, which becomes a special problem in offshore environment, because in this case, the weight is always the main concern. But, fundamentally, flange is an invalid seal, it needs to take 50% of the bolt load for gasket extrusion, while maintaining pressure on the load for only 50%.