Internal obturators for pipes

Claim 1

An internal obturator for a pipe, comprising: a rigid hollow cylindrical unit defined by a hollow central cylinder (39) closed at its opposite ends by two circular plates (37, 38) having annular flanges extending radially outwardly beyond said cylinder, an elongated torus shaped inflatable element (40) disposed around said cylinder, and a flexible sealing wall (48) of cylindrical shape disposed around said inflatable element for sealing application thereby against the internal wall of a pipe, said sealing wall comprising a cylindrical sleeve independent of said inflatable element and retained at its two ends against longitudinal displacement by said circular plates, said inflatable element comprising a single inflatable bladder of annular cross-section inserted between said cylinder and said cylindrical sleeve and having a length approximately the same as that of said cylindrical sleeve, wherein said cylindrical sleeve comprises a deformable cylindrical body freely inserted between said end plates, the axial length of said cylindrical sleeve substantially corresponds to the axial distance between said circular plates, and the portions of the axial ends of said cylindrical sleeve which are, in use, applied against said end plates are made of a stronger material than that of which the remainder of said sleeve is made.