The key component used in pipeline systems and pressure vessels is the flange, which is mainly used for connection. The connection is shaft to shaft, pipe to pipe, and the connection is two devices, and the flange can be used with gaskets and bolts. Used in combination, the connection between fixed pipelines and rotating or reciprocating equipment can be achieved. This is a common connection method in pipeline systems. Of course, if the flange, gasket and bolts are installed correctly, the flange connection can play a sealing role. ; However, in the actual use of flanges, even if the flange is installed correctly, what is the reason for continuous leakage?
In fact, the reason for flange leakage may be that the flange sealing surface at that time is not suitable for the selection of flange sealing surface. For example, flat flanges should be used in wide-face flanges and low-pressure pipeline systems, but they are arbitrary. Flat flanges should be used in high-temperature and corrosive medium pipeline systems; in this case, due to the dual influence of working conditions and corrosive media, flange leakage will occur.
As we all know, there are five types of flange sealing surfaces: flat surface, convex surface (called convex surface in some standards), concave-convex surface, tongue-and-groove surface and ring connection surface; different flange sealing surfaces have different characteristics due to different characteristics. Different characteristics, the application range of FF is also different. For example, flanges with full-plane (FF) sealing surfaces can be used for flanges with low pressure level and temperature requirements due to their smooth surface, simple structural design and convenient processing. Occasion: Irregular surface (MFM) flanges are composed of concave and convex surfaces. Compared with flat flanges, their working environment pressure and management range are both greater than those of flat flanges. It is suitable for enterprises with strict requirements on sealing technology.
In fact, the selection of flange sealing surface is directly related to technical parameters such as medium, temperature, and pressure. Therefore, the flange sealing surface should be selected according to actual conditions.
The selection principle of flange sealing surface form is:
1. Under normal circumstances, convex sealing surface can be selected. For cast iron flanges, flat (FF) sealing surface should be selected as much as possible. When the medium is flammable and explosive, it has a high extreme danger.
2. When the pressure and temperature of the medium, convex surface (RF), concave and convex surface (MF), tongue and groove surface (TG), the danger of the medium is high, and the sealing surface can be selected according to the pressure and temperature of the medium.
3. When the pressure is ≥10.0MPa, convex surface (RF) and ring connection (RJ) sealing surface can be selected.
Well, today I will introduce it here. I hope everyone can understand it and successfully choose the appropriate flange sealing surface to use. Of course, if you want to know more about flanges and pipe fittings, please pay attention to us.
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