,The sealing surface is in the shape of a ring groove, and the sealing is achieved by installing a special metal gasket. Compared with other forms of sealing surfaces, it can provide a better sealing effect under high pressure. Generally, this type of flange is a high-pressure flange, with specifications ranging from DN15 to DN600, varying from small to large. This type of flange is available in a variety of materials, commonly including carbon steel, stainless steel, alloy steel, etc. For example, 316L stainless steel RTJ butt-welding flanges have good corrosion resistance and are suitable for pipeline systems with corrosive media in industries such as chemical engineering and pharmaceuticals; carbon steel RTJ butt-welding flanges have a relatively low cost and high strength, and are suitable for general industrial pipelines. It is mainly applied to the connection of high-temperature and high-pressure pipelines and equipment in refineries and chemical plants, such as the connection between devices like crude oil transportation pipelines, distillation towers, and reactors.
, In the processes of natural gas extraction, transportation, and processing, it is used for the connection of high-pressure natural gas pipelines and the interfaces of related equipment, such as parts like natural gas wellhead devices and valve chambers of long-distance pipelines.
.In thermal power plants and nuclear power plants in the power industry, it is used for the connection of steam pipelines, high-temperature water pipelines, and other pipelines for high-pressure media. For example, it is used to connect the main steam pipeline between the boiler and the steam turbine- The long-necked flange, also known as the high-necked flange or the flanged neck, is a disc-shaped part mainly used to achieve the connection between pipes. The following is an introduction to it:
Outer Diameter (OD) It refers to the overall outer diameter size of the long-necked flange. The sizes may vary under different standards. For example, the outer diameter of DN50 according to the Chinese national standard may be 165mm, while that according to the American standard is 152mm Outer Diameter of the Raised Face (O.D of Raised Face) : For a long-necked flange with a raised face sealing type, it is the outer diameter of the raised face part. Inner Diameter of the Neck It is the inner diameter size of the long-neck part, which matches the outer diameter of the connected pipeline and affects the flow area of the medium. Inner Diameter of the Flange It is the diameter of the central hole of the flange plate. It is related to the inner diameter of the neck and is usually slightly larger than the inner diameter of the neck to ensure that the pipeline can be inserted smoothly. Bolt Hole Pitch : It is the distance between the centers of adjacent bolt holes, which can be calculated by the formula "Hole Pitch = PCD×sin(180°/Number of Holes)", where PCD is the diameter of the bolt hole center circle. Total Height of the Flange It is the vertical distance from the bottom of the flange plate to the top of the long neck, which has an impact on the installation space and the coordination with other components. Chamfer Size At the connection between the flange plate and the long-necked pipe, in order to reduce stress concentration and facilitate processing and installation, a chamfer is usually set. The size of the chamfer generally specifies parameters such as its radius or angle.




