MANDREL FOR SIZING DUCT OF PIPELINE Russian patent published in 1995 - IPC

FIELD: metal pressure forming. SUBSTANCE: mandrel for sizing a duct of a pipeline includes the portion 4 in the form of a cone with an acute angle towards motion direction, a row of shaping steps with annular grooves between the steps, a guiding portion in the form of a cylinder, joined through a terminal annular groove with the last shaping step, having on its surface an inlet deeding passage in the form of a helical groove, an axial passage, connected at one side with a non-worked portion of the duct of the pipeline and at other side through radial ducts with the terminal annular groove. Upon action of a pressure of working fluid upon the guiding portion of the mandrel the last begins to move in the duct of the pipeline in such a way, that the inlet cone and the guiding portion provide self-aligning of the mandrel. At action of a pressure droop, being created on the mandrel in the result of throttling of a flow of the working fluid, and a lateral hydrodynamic component, in the helical groove of the mandrel a torque is being occurred, for turning the mandrel, being moved in the duct of the pipeline. EFFECT: enhanced accuracy of sizing. 5 cl, 5 dwg