What is a flange?

A flange is a protruding rim, ring, or collar on an object, usually a pipe, valve, or fitting. Its primary purpose is to provide a surface for connection to another object, typically using bolts or welding. Here's a breakdown of key information about flanges:

Key Functions:

Joining Pipes and Equipment: This is the most common use. Flanges allow for the easy connection and disconnection of pipes, valves, pumps, and other equipment without the need for welding in many cases. This simplifies maintenance and repair.
Creating a Seal: The mating surfaces of two flanges, along with a gasket placed between them, create a seal to prevent leaks of liquids, gases, or vapors.
Strength and Support: Flanges add structural rigidity to the piping system, enhancing its overall strength and stability.

Types of Flanges:

There are many different types of flanges, categorized by:

Facing: The surface of the flange that makes the seal (e.g., raised face, flat face, ring type joint). The facing type dictates the type of gasket used.
Material: Flanges are made from various materials, including steel (carbon steel, stainless steel), cast iron, ductile iron, and plastic, depending on the application and the fluid being handled.
Type of Connection: These include weld neck, slip-on, blind, threaded, lap joint, and socket weld flanges. Each type has specific design features and installation methods.
Pressure Rating: Flanges are designed to withstand specific pressures, indicated by a pressure class rating (e.g., 150#, 300#, 600#, etc. in pounds per square inch).
Standard: Flanges are designed according to various industry standards (e.g., ASME B16.5, ANSI B16.47). These standards specify dimensions, tolerances, and pressure ratings.

Components of a Flange Assembly:

Flange: The main component, described above.
Gasket: A compressible seal placed between the flanges to prevent leakage. Gasket materials vary depending on the application (e.g., rubber, asbestos, PTFE).
Bolts and Nuts: These secure the flanges together, compressing the gasket.
Optional Items: Studs (bolts that go through the whole flange assembly), washers (to distribute the load of the bolts)

Applications:

Flanges are used in a vast range of industries, including:

Oil and Gas: High-pressure pipelines and processing equipment.
Chemical Processing: Handling corrosive and hazardous materials.
Power Generation: Steam turbines and boilers.
Water Treatment: Piping systems for water distribution and purification.

In summary, flanges are crucial components in piping systems and equipment, providing reliable connections, seals, and structural integrity. The specific type of flange used depends heavily on the application's requirements.