APPARATUS AND METHOD FOR MOVING A FERROMAGNETIC ELEMENT

摘要

A device and technique for placing and moving a ferromagnetic element in an annulus between coaxially arranged cylindrical tubes. The device includes an electromagnetic ram moved along the interior of a cylindrical tube. The movable ferromagnetic element is magnetically coupled to the electromagnetic ram and moved by magnetic force to a location in the annulus defined by the tubes an d magnetically coupled to the electromagnetic ram for movement in and removal from the annulus.