The sealing principle of the ship's mark welded flange:
The two sealing faces of the bolt squeeze the flange gasket together to form a seal, but this also leads to the destruction of the seal. To maintain the seal, the force exerted by the bolt must be sustained, necessitating a larger bolt. Larger bolts require larger nuts, meaning that conditions must be created for larger bolt diameters to tighten the nuts. However, as the bolt diameter increases, the applicable flanges become more convoluted, and the solution is to increase the wall thickness of the flange section. The entire equipment will require larger dimensions and weight, which poses a particular question in offshore environments, as weight is always a major concern. Moreover, fundamentally, a welded flange is an ineffective seal, requiring 50% of the bolt load to compress the gasket, leaving only 50% for maintaining pressure.
The ship's mark welding flange not only saves space and reduces weight, but most importantly, it ensures that there will be no leakage at the joint, offering excellent sealing capabilities. The compact flange size is reduced due to the decreased diameter of the sealing components, which in turn reduces the cross-sectional area of the sealing surface. Furthermore, the flange gasket has been replaced by a sealing ring to ensure a proper match between the sealing surface and the mating surface. This way, only minimal pressure is needed to tightly seal the mating surfaces.
Weld neck flanges with a higher neck height enhance the rigidity and load-bearing capacity of the flange. Their purpose is to transfer pressure, thus reducing stress concentration at the base of the flange. Also known as high-neck flanges, they have greater rigidity and are suitable for high-pressure and high-temperature environments. Production processes include forging, casting, rolling, etc. Production equipment includes lathes, drills, CNC machines, etc. Applications range from boilers and pressure vessels, petrochemicals, shipbuilding, metallurgy, machinery, stamping elbows, and food industries. Field installation is convenient, allowing for the elimination of the weld seam rubbing process. According to standards, there are flat welding steel pipe flanges --- GB9115.1, and raised face welding steel pipe flanges --- GB9115.6.
