Flanges for Pressure Vessels

Flanges are essential components in the design and construction of pressure vessels. They connect pipes, valves, and other equipment to the vessel, ensuring a secure and leak-proof seal. Flanges play a crucial role in maintaining the structural integrity and safety of pressure vessels.
 

During the design and manufacturing process, pressure vessels require various types of flanges to connect pipes, valves, pumps, and other equipment. Different types of flanges have their own characteristics and applications. Flanges commonly used in pressure vessels include slip-on flanges, weld neck flanges, lap joint flanges, blind flanges, threaded flanges, socket weld flanges, ring type joint flanges, swivel flanges, and integral flanges.
 
A slip-on flange is easy to install and is suitable for medium and low-pressure, small-diameter pipeline systems. It is connected to pipelines by welding. A weld neck flange has a long neck, increasing its strength when connected to the pipeline and making it suitable for high-pressure and high-temperature applications. It uses groove welding, which effectively prevents leaks. A lap joint flange is used for pipeline systems that need to be frequently disassembled and cleaned, often paired with loose flanges. It facilitates easier disassembly and assembly, but has a low pressure-bearing capacity. A blind flange cover is used to close the pipe port. It has no holes and is suitable for situations requiring pipe closure, such as temporary plugging during equipment maintenance. A threaded flange connects to the pipe through threads, making it suitable for low-pressure and small-diameter pipe systems. It is easy to install but unsuitable for high-pressure and high-temperature environments. A socket weld flange is used in small-diameter and high-pressure pipe systems. During welding, the pipe is first inserted into the flange and then welded to ensure good sealing performance. A ring groove flange is suitable for harsh environments with high pressure and high temperature. It achieves reliable sealing by pressing a metal ring with a groove on its sealing surface. A ring groove flange is commonly used in the petroleum, chemical, and other industries. A lap joint flange is welded to the short pipe section and then connected to the pipe. It is suitable for low-pressure pipe systems that need to be disassembled frequently. Its advantage is that it is easy to install, but the sealing performance and strength are low. A swivel flange is typically used for submarine pipelines and in situations requiring alignment adjustment. It can be rotated and adjusted during installation to facilitate connections. An Integral flanges is cast or forged as a whole with the pipeline, offering high strength and good sealing performance, making it suitable for high-pressure and high-temperature environments.
 

The design of pressure vessel flanges must comply with relevant international and national standards to ensure their safety and reliability during use. The main design standards include ASME B16.5, ASME B16.47, EN 1092-1, and GB/T 9112-9124. ASME B16.5 applies to flanges with nominal diameters ranging from 1/2 inch to 24 inches. ASME B16.47 is suitable for large-diameter flanges with nominal diameters from 26 inches to 60 inches. EN 1092-1 is a European standard covering flanges from DN 10 to DN 4000. GB/T 9112-9124 is a Chinese national standard covering flanges from DN 10 to DN 4000.
 

Manufacturers select materials for pressure vessel flanges based on the environment and media. Commonly used materials include carbon steel, stainless steel, alloy steel, copper, and copper alloy. These materials are suitable for general media and medium to low-temperature environments due to their low cost and high strength. They are suitable for corrosive media and high-temperature environments, offering good corrosion resistance, albeit at a higher cost. These materials are suitable for high-pressure and high-temperature environments, offering excellent mechanical properties and corrosion resistance. They are suitable for specific corrosive media, such as seawater systems, but have low strength.
 

Pressure vessel flanges are widely used in petroleum, chemical, electric power, metallurgy, shipbuilding, natural gas, and other industries. In these industries, flanges connect pressure vessels, pipelines, valves, and other equipment to ensure system sealing and safety.
 

Pressure vessels must choose the appropriate flange type under various working conditions and environments to ensure system reliability and safety. When designing and selecting flanges, consider factors such as working pressure, temperature, medium properties, installation, and maintenance to ensure proper compatibility with the pipeline system. Properly selecting the flange type can effectively enhance the operating efficiency and safety performance of the pressure vessel.