If we categorize flanges based on their construction and applications, they are summarized in the following cases:
Raised Face Flange: As it is clear from the name of the edged flange, the surface of the flange has a protrusion relative to the edge and is higher than the location of the holes. This flange model is one of the most widely used flange connections in various industries. It is interesting to know that the possibility of using all kinds of washers for sealing is one of the advantages of raised flange.
(Flat Face Flange): The surface of the flat flange, unlike the edged flange, does not have protrusions and is completely flat and smooth. This smoothness of the surface makes the used gasket to be in contact with the entire surface of the flange. The application of this type of flange is mostly for pumps and when it is possible that the torque caused by the compression of the gasket will damage the flange.
Types of flange connection
(Threaded Flange): A threaded flange, which is also known as a rib, as the name suggests, has threads in its inner part. To connect using this flange, there is no need to weld between the pipes and it is done only through the connection thread so that the flange is connected to the pipes that have an external thread. It is worth noting that gear flanges are mostly used for low pressures and small diameters.
(Ring Type Joint Flange): In the flange ring joint, a ring is considered between two flange plates, which is put under pressure after connecting the two flanges using bolts and nuts, and sealing is done. This type of flange is mostly used when the system is involved with high pressure and temperatures.
(weld neck flange): The reason for naming this flange is the conical part that is like a throat on the surface of the flange. The normal model of this flange, unlike the long model, is useful for piping.
(Slip On Flange): The slipon flange is a good alternative to the throat flange because it does not require diagonal welding and the pipe can be adjusted relative to the position of the flange.
(Blind Flange): This flange has a fundamental difference with other flanges because, unlike the flanges we have mentioned so far, it is not made for the passage of fluids and its outlet is blocked, which is used to close the ends of pipelines.
(Lap Joint Flange): Maybe this type of flange has standard dimensions like other flanges, but they don’t have the protrusion of the surface related to the gasket, but this is an advantage because in this case there will be no worries about adjusting the holes. Regarding the application of flanged lap joint, it should be said that it is often more suitable for projects that require frequent opening and closing.
(Socket Weld Flange): The silent weld flange needs to be welded from both the outside and the inside because if we do not do the welding from the inside, the static resistance will increase. This flange is used in systems with small pipe diameter and high working pressure.
Now that we are familiar with the types of flanges used in industries, we will explain the application of these flange connections more widely.
Application of flange connection
It is true that the cost of flanged connection may be higher than that of welding, but manufacturers prefer using this connection because of the advantages it has over other connections. These advantages can be summarized in the following 3 items:
Suitable for making changes in the size and material of the pipe
Ability to connect to pipes that need to be separated
The possibility of connecting to valves, pumps, etc.
Flange connection is used in various industries due to the advantages we mentioned and many other reasons. The main applications of flange types are:
Oil and gas industry
Water and sewage industry
Construction of vacuum chamber
Connecting telecommunication towers
Food industry
Nuclear facilities
