MANDREL SEAL PORTION

摘要

A mandrel seal part is provided to prevent forcing a back up ring into an outer circumference of a fixing ring by inserting the back up ring added pressing force into accommodation space. A mandrel seal part comprises the followings: an aqua tube(3) expanding a diameter by filling high pressure; a back up ring(4) mounted on an outer peripheral part of a mandrel main body(2) according to a front and rear cross section of the aqua tube; a fixing ring(5) mounted according to the cross section of the back up ring; an annular expansion ring(6) expanded to a diametric direction.