Flange connection is also the simplest connection method with cast iron pipes and steel pipes. The Blind Flange can be used on the opening of the inspection port. In addition, flange connection is suitable for the connection of pipe fittings with pipe diameter from φ50-315mm. Its performance characteristics: non-rigid connection, removable, tensile strength. The flange connection method is usually used as a detachable connection on the low-pressure transmission pipeline.
With the rapid development of long-distance pipeline construction at home and abroad, pipeline pressure test has become an indispensable important link. Before and after the pressure test, each section of the pipeline must be ball-swept, the number of times is generally 4 to 5 . Especially after the pressure test, the water in the pipeline is difficult to clean, and the cleaning frequency will be more. The construction method of re-welding the head at the receiving place has problems: one is to increase the labor intensity of the workers; the other is the high consumables, the need for large-scale equipment, and the high cost. Aiming at the problems of high labor intensity, high consumables, large-scale equipment required, and high cost when the repeated welding head method is used at the service point when the ball is swept after the pressure test of the long-distance pipeline, a new method is proposed. Simple and quick opening Blind flange construction method. The construction method introduces the structure, working steps and strength check of the quick-opening blind plate. Through the application in the Se-Ninglan gas pipeline project, it is proved that the quick-opening Blind Flange construction method is three times more efficient than the repeated welding head construction method, which not only reduces the labor intensity of the workers, but also reduces the cost.