Flanges play a crucial role in creating a secure connection for pipes, valves, pumps, and other components, forming a leak-proof piping system. They come in various types, each serving specific purposes and applications. Let’s delve into the seven main types of flanges commonly used in piping systems.
1. Slip-on Flange : Connecting with Fillet Welds – Slip-on flanges make connections through two fillet welds, one within the flange cavity and another outside it. As the name suggests, these flanges slip over the pipe, requiring a fillet weld for a secure connection. They are commonly employed in fluid pipelines due to their design.
2. Threaded Flanges : Simplifying Connection – Similar to slip-on flanges, threaded flanges are bored out to fit the inner diameter of specific pipes. These flanges save time and money, especially for small-diameter piping systems, and are the preferred choice in areas where welding poses risks.
3. Weld Neck Flange : Handling High Pressure and Temperature – Weld neck flanges, also known as high-hub or tapered hub flanges, are designed to reduce pressure build-up at the flange’s bottom. They are suitable for pipes operating at varying temperatures and pressures, with effective utilization even at pressures as high as 5000 psi.
4. Socket Weld Flanges : Single Fillet Weld for High-Pressure Systems – Socket weld flanges connect to pipes with a single fillet weld executed outside the flange. The bottom clearance minimizes residual pressure build-up during the welding process. These flanges are ideal for compact, high-pressure pipe systems carrying non-corrosive liquids.
5. Blind Flange : Blocking Off Unused Sections – Blind flanges, without a bore, block the flow of fluids, sealing pipe ends. They withstand significant mechanical stress and find use in pressure checks or when not all nozzles on a tank are in use. When paired with the right gaskets, they offer an excellent seal in high-temperature conditions.
6. Lap Joint Flange : Affordable Mechanical Connection – Lap joint flanges, used with a stub end, provide a cost-effective mechanical connection. Unlike slip-on flanges, they have a radius where the flange face meets the bore. Bolts secure the lap joint flange to the stub end, offering an economical option for certain pipelines.
7. Long Neck Weld Flanges : Handling High-Pressure and Temperature in Oil & Gas – Long neck weld flanges, similar to standard weld neck flanges, have a longer neck or tapered hub. They are utilized in high-pressure and high-temperature conditions, commonly in the oil and gas industry, especially for anchoring water mains or gas sources in extensive pipe networks.
In addition to the standard flanges, there are special types designed for specific needs:
1. Weldo Flange / Nipo Flange : Combining Functionality – Combining a welding neck flange with a forged Nipolet, Weldo flanges offer a versatile solution for 90-degree branch pipes.
2. Elboflange and Latroflange : Unconventional Combinations – Less common but useful, Elboflanges combine a flange with an Elbolet, branching off a pipeline at a 45-degree angle. Latroflanges, a combination of a flange and a Latrolet, serve specific purposes.
3. Orifice Flange : Measuring Flow Rate – Used with orifice meters, orifice flanges help determine the volumetric flow rate of liquids or gases within a pipeline.
4. Expanding Flange (Expander): Adjusting Pipeline Bore – Expanding flanges, or expander flanges, are employed to increase pipeline bore or connect pipes to equipment with different inlet sizes.
5. Reducing Flange (Reducer) : Altering Pipe Size – Reducing flanges, or reducer flanges, perform the opposite function, decreasing pipe size when needed.
Understanding these various flanges is essential for creating efficient and reliable piping systems tailored to specific requirements. Each type serves a unique purpose, contributing to the overall functionality and safety of the system.
