Several Kinds of Flanges in Common Use
The flange is the connecting part between two pipes or two equipment. Flange, as a component, involves a wide range of aspects in engineering design. It is an essential part of pipeline system, pipe fittings and valves, and also an important component of equipment. Additionally, flange is usually applied to industrial furnaces, thermal engineering, water supply and drainage,etc.
Material: malleable iron, casting iron, carbon steel, stainless steel
Several kinds of flanges and their features
1. Plate flanges (PL)
Advantages：
It is convenient to manufacture, low cost and widely used.
Disadvantages:
Due to its poor rigidity, it should not be used in chemical pipeline systems which have requirements of supply and demand, flammability, explosiveness and high vacuum degree, and in highly hazardous situations.
2. Threaded flanges (TH)
Threaded flange is a non-welded flange. The inner hole of the flange is processed thread and used together with the thread end pipe.
Advantages:
Convenient installation and maintenance. It can be used on some pipelines that are not allowed to be welded on site.
Disadvantages:
When the temperature of the pipeline system changes sharply or the temperature is higher than 260 ℃ and lower than - 45 ℃, threaded flange is not recommended to avoid leakage.
3. Blind flanges(BL)
Blind have not holes in the middle of flange for sealing pipe. Same as the pipe cap, it can be pulled down at any time when not needed.
4. Weld neck flanges (WN)
Advantages:
Not easy to deform, good sealing effect, extensively used.
It is suitable for pipelines with temperature or pressure fluctuation by a wide margin, and transporting expensive media, flammable and explosive media, and toxic gas.
Disadvantages:
Weld neck flange occupies a large space, is heavy weight and not economic, difficult to install.
5. Socket welding flanges (SW)
It is welded by steel pipe at one end and bolted at the other end.
Application flied: boiler and pressure vessel, petroleum, chemical, shipbuilding, pharmaceutical, metallurgy, machinery, food and other industries,used in pipelines with PN ≤ 10.0MPa and DN ≤ 40.
6. Slip-on flanges (SO)
Advantages:
Easy to install. The process of welding seam rubbing can be omitted.
Disadvantages:
Large welding workload, high consumption of welding rod, unable to withstand high temperature and high pressure, repeated bending and temperature fluctuation.
