How should the connection method for valves be selected?
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I would like to ask the experts: valves can be connected using welding, flanges, threads, socket connections, and other methods. What are the advantages and disadvantages of each of these connection methods? How should one choose the connection method for valves? Are there any national standards with relevant requirements? Thank you! The more detailed, the better!
These days, the common connection methods for valves are flanges or threads, right? Valves with direct welding are truly rare; not only does the high temperature during welding affect the valve’s sealing surfaces, but they are also very difficult to repair or remove. Valves with cartridge connections are generally small-diameter quick-release valves, such as those used on air pipes or sampling tubes. Threaded connections are more commonly used for small-diameter ball valves, such as those with a diameter of DN50 or less. Flange connections are generally used as well, as they are easy to install and facilitate disassembly, assembly, and replacement.
The most commonly used types are flanged or threaded; clamps are generally used on sanitary-grade valves, while welded types are more often used in ball valves. Different applications require different types
Threads are suitable for low pressure and small diameters; flanges have a wider range of applications, while welding is generally used for medium and high pressures and above
Look, how professional this reply is. Come and be the moderator of the valve section. Clamp-type ones are also used on some dry-material pipelines, such as those for cement; they are similar to products like Grayloc.
There is no standard for choosing what type of connection to use
It depends on the specific medium and environment. Generally speaking, large-diameter valves are installed using flanges, which makes them less prone to leakage; they are also easy to disassemble and replace. However, their installation is complicated and increases costs! Screw-mounted valves are generally used for small-diameter valves; they are easy to install but difficult to remove. Clamps and collets are generally used in applications where the pipeline pressure is not high, such as in fire protection systems; they are easy to install and convenient to remove! I just can’t handle too much pressure!
Many natural gas valves use welding connections, with a maximum diameter of 56 inches. Welded joints are generally used in environments with high temperatures, high pressures, flammable and explosive substances, or toxic materials