What Are Pipe Flanges, and How Do They Work?

What Are Pipe Flanges, and How Do They Work?

January 13, 2021

What is a pipe flange? It is a connection bolt used to join pipes after welding in San Jose, CA. Flanged connections include pipe flanges, bolting and gaskets, which all work together to keep pipes and hoses in one piece. Pipe flanges are not all the same, and their design depends on their application. Here are seven common flange types and how they work:

  • Threaded: A threaded flange is also known as a screw flange. It contains a thread inside that’s designed to fit with a matching thread on a fitting or pipe. Using this flange often allows you to skip the welding phase and simply put the pipe together. You just need to ensure you purchase the right threading match for your project.
  • Socket-weld: The socket-weld flange is likely the easiest to secure tightly. Used for applications exposed to high-pressure and low-temperature conditions, it allows you to place the pipe into the flange and connect it with a multi-pass fillet weld. It offers the same security as a threaded flange but without the limitations presented by matching threads.
  • Slip-on: You can find slip-on flanges in a range of sizes and use them for many applications. They are most common for functions handling high flow rates. Match the flange to the outer diameter of your pipe, and connect with a weld. You need to fillet weld both sides to secure this flange, making it tight but more challenging to handle.
  • Lap joint: The lap joint has a two-piece design. It requires a butt welding on the stub end of the pipe or fitting and a backing flange to finalize the connection. Lap joints are most popular for projects completed in tight systems that must remain accessible for frequent maintenance.
  • Weld neck: Like lap joint flanges, the weld neck requires butt welding to install. However, these work well for process piping with frequent bends, high temperatures and high pressure. They are a popular connection for these systems because they stay secure despite their demands—any systems where you must avoid leaks or that are difficult to repair benefit well from the weld neck.
  • Blind flanges: The blind flange is basically a boltable blank disc. It is most commonly used for isolating and terminating piping systems, and it produces an impressive seal. However, these flanges are also easy to remove when repairs become necessary. If you choose these flanges, double-check your gaskets and use the correct ones. Otherwise, you risk connection failure.
  • Specialty flanges: Common flanges work for most projects. It is just a matter of understanding the circumstances and creating the best pipe connections possible. But there are specialized flanges for demanding or unique environments. In addition to these types, you may find nipoflanges, expanding flanges, orifice, long weld neck, reducing flanges or weldoflanges to work better. Ask a reputable hydraulic and pneumatic supply provider to see if your project requires something more customized.

Royal Brass Incorporated includes common flange types in our inventory in San Jose, CA. If you want more answers to questions about pipe flanges, call today to learn more and order products.

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