Flanges are practical connections for connecting pipes to each other or connecting pipes to equipment such as pumps, valves, etc. The welding flange is connected to the pipe or equipment through welding or screwing and is closed to the opposite flange by means of a screw.
The use of flanges facilitates the replacement or repair of piping components and provides a safe and reliable connection.
Specifications of flanges
According to the standard, the specifications of the flange must be engraved on the flange. For example, according to the image below, from left to right, it includes the following items:
- The brand name of the flange manufacturer
- The nominal size of the pipe (the external diameter of the pipe to which the flange is welded.)
- Flange class (standard working pressure)
- Flange category (determining the inner diameter and thickness of the end of the flange wall)
- Dimensional standard
- The standard of raw materials used in the manufacture of flanges
- The number or code related to the melting number of the raw materials used
- Production number (to trace the series and time of production in the factory, which is optional)
Flange size
It is a nominal and conventional size that is suitable for a pipe of the same size and determines the outer diameter of the flange bottom, the diameter of the fluid passage and the outer diameter of the flange throat.
Flange category
The number is set to determine the thickness of the wall and the inner diameter of the flange, which must be equal to the pipe that will be connected to the flange. In throat flanges, the grade determines the thickness of the wall edge and the inner diameter of the flange, and in silent weld flanges, it indicates the inner diameter of the flange, but it is not applicable in other types of flanges.
Flange class
It shows the pressure tolerance of the flange, the higher the class, the thicker the bottom of the flange, and as a result, its resistance increases. According to the standard, flanges have classes 75, 150, 300, 600, 900, 1500 and 2500. In the API standard, flanges have higher pressure tolerance and are produced in classes 2000, 3000, 5000, 10000 and 15000.
