Flanged connection valve

Flange-connected valves are manufactured using flanges that comply with the national standards of the People's Republic of China, namely GB/T 9112~9124-2010. These standards cover 13 different types of flanges, including integral flanges, necked threaded flanges, and butt-welded flanges, making them suitable for various welding processes and structural requirements. The technical specifications for these flanges utilize a dual-pressure marking system based on PN and Class ratings. The PN rating range includes 12 levels, from 2.5 to 400, while the Class rating range covers 6 levels, from 150 to 2500. National standard flanges have strict requirements regarding dimensional tolerances and material specifications; only qualified steel materials must be used to ensure satisfactory mechanical properties and welding reliability, which differentiates them from non-standard products that may use reduced dimensions or inferior materials. The accompanying standard GB/T 12221—2005 specifies the structural length parameters of flange-connected valves, covering a diameter range of DN3 to 4000 mm and pressure levels below 42.0 MPa. It also outlines the measurement methods for various connection types, such as straight-through and angle-type connections. Flanges are available in different connection formats, including FF (flat face), RF (raised face), and RTJ (ribbed and tongue). The technical specifications of these flanges are mutually recognized with international standards such as EN and ASME, making them suitable for a wide range of valve types, including gate valves, globe valves, and ball valves.

Tags: valve