Abstract: A sealing arrangement around an end of a pipe received in a testhead of a hydraulic pipe testing apparatus, which sealing arrangement consists of an elastic sealing ring and an adjacent, rigid support ring of varying diameters. Both rings are mounted in radial recesses in the testhead and encircle the pipe upon its entry into the testhead. The recess for the elastic sealing ring consists of a flat ring located between the sealing ring and the rigid support ring. For a sealing condition, the support ring is contracted to abut the pipe and the sealing ring is caused to be deformed whereby it flows radially outwardly from its recess against the pipe and axially along the pipe towards and away from the pipe's end. In the axial direction away from the end of the pipe, the sealing ring flows around the flat ring to abut the rigid support ring.

Abstract: A mechanical pipe expander for a step-by-step expanding of steel pipes formed with a spiral welded seam. The expander includes an expander head that performs the expanding made up of circumferentially arranged segments over which the pipe assumes a circumjacent position and after which the segments move radially outward to forcibly engage the inside of the pipe. In order to avoid the segments contacting the inside welded seams of the pipe, the segments are formed with one or more complementary spiral slots and if the pipe has cross welded seams with one or more corresponding cross spiral slots.

Abstract: The expander is constructed from an irregular, truncated polyhedral pyramid in which surfaces bounded by parallel edges alternate with surfaces of trapezoidal contour. The latter have T-shaped longitudinal grooves each receiving respectively the T-shaped foot portion of double T-contoured guide elements and being secured to the groove from axial ends of the pyramid.