Abstract: A packing for use in a steel-pipe hydraulic testing apparatus, consisting of: an annular body having an annular cut in its inner peripheral portion; a plurality of backing pieces fastened to the wall of the annular cut at a given circumferential spacing and directed in the radial direction; and a plurality of adapter pieces embedded in the inner peripheral walls of the annular body of the packing at a given circumferential spacing and exposed to the annular cut, so that the aforesaid plurality of backing pieces may be each slidable on the surfaces of a pair of adjoining adapter pieces. This packing is contracted due to a hydraulic pressure being applied to the outer periphery of the body of the packing, and as a result the respective adapter pieces will slide on the surfaces of the adapter pieces in the circumferential direction of the packing.

Abstract: A packing for use in a steel-pipe hydraulic testing apparatus, consisting of: an annular body having an annular cut in its inner peripheral portion; a plurality of backing pieces fastened to the wall of the annular cut at a given circumferential spacing and directed in the radial direction; and a plurality of adapter pieces embedded in the inner peripheral walls of the annular body of the packing at a given circumferential spacing and exposed to the annular cut, so that the aforesaid plurality of backing pieces may be each slidable on the surfaces of a pair of adjoining adapter pieces. This packing is contracted due to a hydraulic pressure being applied to the outer periphery of the body of the packing, and as a result the respective adapter pieces will slide on the surfaces of the adapter pieces in the circumferential direction of the packing.