Patent ID: 8794636

Claim:
A self-sealing flexible seal capable of moving along a surface of an internal pipe, comprising: a first seal component having a hollow ball shape and one annular opening at a pole part thereof, said first seal component being formed of a flexible material; and a second seal component having a hollow ball shape and one annular opening at a pole part thereof facing the pole part of the first seal component, said second seal component being formed of a flexible material and having a shape similar to that of the first seal component, wherein said first seal component is arranged on an outer surface of the second seal component and said second seal component is arranged on an inner surface of the first seal component to closely contact with the first seal component, each of said first seal component and said second seal component includes a plurality of slit pieces in a number of N having a similar shape and extending from a near side of one of the annular openings to a near side of the other of the annular openings, and said first seal component and said second seal component are arranged so that the first seal component is shifted relative to the second seal component on a plane intersecting a central axis of the first seal component and the second seal component by a phase angle between the first seal component and the second seal component.