Flanges of different sizes
Variable diameter flange, also known as Reducing Flange, and its inner diameter and the standard flange diameter, there are some differences.In engineering, when the standard flange can not match the fittings and pipes, the reducing flange is used.China's national standards flange standard (GB) and chemical industry standard (HG) two categories, the new chemical industry standard HG/T20592 ~ 206352009 flange is used to the EN as the representative of the European standard pipe flanges (nominal pressure expressed by PN) and the United States as the representative of the American ASME system (nominal pipe flange the pressure expressed by Class), between them the nominal size of the feature size is different; moreover, our country pipeline diameter series is also divided and metric Inch series series, there are differences in the nominal size; in addition, when there are special requirements, such as flange instrument joints, when the glass lined the characteristics of some special requirements (give it a separate "glass lining of different diameter flange" HG/T2140-2009 standard). Therefore, the inevitable mixing in the project, the use of reducing the flange diameter of the method is the simplest and most effective solution, thus the emergence of non-standard variable flange.
If the outer diameter is not big, the bolt hole, the middle diameter and the bore diameter can be unified. If the specifications are different and can not be directly connected, you can use the big head as an excessive.
