A flange, also known as a flange or flange, is a component that connects shafts and is used to connect pipe ends. It can also be used on equipment inlets and outlets, connecting two pieces of equipment. There are many different types of flanges, and they can be categorized from various perspectives. The following are some common classification methods:
1. Classification by Structure
Slip-on flange (PL): Also known as a lap flange, this is a relatively simple flange consisting of two welded steel plates. It is typically used to connect low-pressure pipelines.
Weld-on flange (WN): It consists of two butt-welded steel plates or forgings. It is typically used to connect medium- and high-pressure pipelines.
Socket-weld flange (SW): One end is welded to the steel pipe and the other end is bolted. It is commonly used for pipelines with a pressure difference of PN ≤ 10.0 MPa and a diameter of DN ≤ 40.
Threaded flange (Th): The inner hole of the flange is machined into pipe threads, which are used to connect to threaded pipes. This is a non-welded flange suitable for applications where welding is not permitted on-site.
Lap flanges: These include butt-weld and flat-weld flanges. They are primarily used to save material or facilitate construction. Their structure allows the flange and pipe to be made of different materials.
Blind flanges: Flanges without a central hole are used to seal pipe plugs, similar in function to welded end caps and threaded pipe caps.
II. Classification by Material
Carbon Steel Flanges: Made of carbon steel, commonly used for general industrial pipe connections.
Stainless Steel Flanges: Made of stainless steel, suitable for connecting pipes handling corrosive media.
Alloy Steel Flanges: Made of alloy steel, suitable for connecting high-temperature and high-pressure pipes.
Copper Flanges: Made of copper, commonly used for connecting water supply pipes.
Plastic Flanges: Made of plastic, suitable for connecting plastic pipes.
III. Classification by Sealing Surface Type
Raised Face (RF): The most common sealing surface, suitable for most applications.
Meat-Mounted Face (MFM): Suitable for slightly higher pressure applications.
Tongue-and-Groove (TG): Suitable for flammable, explosive, or toxic media and for applications handling high pressures.
Full-Flat (FF): Suitable for applications with low pressure and non-toxic media.
Ring Joint (RJ): Used in specific high-pressure sealing applications.
IV. Other Classification Methods
Flanges can also be classified by diameter, pressure, application, and other methods. For example, by diameter, they can be divided into large-diameter and small-diameter flanges; by pressure level, they can be divided into low-pressure, medium-pressure, and high-pressure flanges.