CONTINUOUS FLOW VALVE INSERTION METHOD

PROBLEM TO BE SOLVED: To form an opening and insert a gate without rotating a case, without a risk of producing fine chips, in a resin existing pipe.SOLUTION: A valve insertion method includes: an assembly process of sealing a part of an outer surface of a resin existing pipe 1 with a sealing case 20 in an air-tight state; a pressing process of pressing a blade edge 40 of a die cutter 4 extended in a width direction R of the existing pipe 1 and having a cut-out width W of a size of an inner diameter D of the existing pipe 1, to the outer surface of the existing pipe 1; a cutting process of moving the die cutter 4 with its blade edge 40 pressed without rotating it toward a center of the existing pipe 1 and thus cutting out a cut piece 14 from the existing pipe 1 by the die cutter 4, thus forming an opening 11 having a width of the size of an inner diameter D of the existing pipe 1; a removing process of removing the die cutter 4 together with the cut piece 14 from the case 20; and a mounting process of mounting a gate 8 capable of intruding within the existing pipe 1 from the opening 11 and stopping a flow of fluid in the existing pipe 1, to the case 20.