Blind flange is the connecting device of two large diameter pipelines

　　Blind flange is the connecting device of two large diameter pipelines, usually two flanges with several fastening bolts. A large blind flange is a steel flange. Low carbon steel has good plasticity and low strength. When carbon is added, it will become hard and its plasticity will decrease and strength will increase. ASTM A105 Carbon Steel RF Blind Flange connections may need to withstand high tensile, compressive, torsional and shear strength. Carbon steel blind flange is a better choice. Generally used in pipelines, in that case, loosening bolts can rotate both sides of the pipeline, and then tightening can be more convenient to disassemble and assemble the pipeline material is carbon steel blind flange called carbon steel blind flange.

　　With the rapid development of long-distance pipeline construction at home and abroad, pipeline pressure testing has become an indispensable and important link. Before and after pressure testing, it is necessary to sweep each pipeline globally, usually 4-5 times. Especially after pressure test, it is difficult to clean the water stored in the pipeline, and the times of cleaning will be more. There are some problems in the construction method of repeated welding head at ball receiving place: firstly, to increase the labor intensity of workers; secondly, the method of repeated welding head has high consumables, many times of large-scale equipment and high cost. In order to solve the problems of high labor intensity, high consumables, many times of large-scale equipment and high cost when the long-distance pipeline is swept through the ball after pressure test, a new construction method of quick-opening blind flange is proposed.