An expansion tool includes a working element configured to expand an end of a tube. The working element includes a plurality of jaws movable between a closed position and an expanded position. The expansion tool also includes first mandrel with a first contact surface and a second mandrel coupled to the first mandrel. The second mandrel has a second contact surface. The first mandrel and the second mandrel are movable together relative to the jaws between a retracted position and an extended position. The first contact surface and the second contact surface are engageable with the jaws to move the jaws from the closed position toward the expanded position in response to movement of the first mandrel and the second mandrel from the retracted position toward the extended position.

An expansion tool includes a housing, a motor supported by the housing, a mandrel, and a drive mechanism configured to convert a rotational input from the motor into translational movement of the mandrel between an extended position and a retracted position. The expansion tool is configured to perform cycles of axially extending and retracting the mandrel. An elapsed time for one cycle of moving the mandrel from the retracted position to the extended position and back to the retracted position defines a cycle time of the expansion tool. The cycle time is one second or less.

A method of manufacturing a clamping ring for a cold-expansion joining system includes providing an extruded pipe part made of a cross-linked polymeric material where, while extruding the pipe part, the inner diameter is formed bigger than the outer diameter of a flexible cross-linked polymeric pipe onto which the clamping ring is positioned before making a pipe connection; providing an injection molded annular part having an inner diameter formed smaller than the inner diameter of the extruded part; and bonding the parts together to form a clamping ring having an inward protruding stop edge at one of its ends. The embodiments further relate to a clamping ring formed from an extruded pipe part made of a cross-linked polymeric material and an injection molded annular part bonded together to form a unitary structure including an inward protruding stop edge at one of its ends.

A method of manufacturing a clamping ring for a cold-expansion joining system includes providing an extruded pipe part made of a cross-linked polymeric material where, while extruding the pipe part, the inner diameter is formed bigger than the outer diameter of a flexible cross-linked polymeric pipe onto which the clamping ring is positioned before making a pipe connection; providing an injection molded annular part having an inner diameter formed smaller than the inner diameter of the extruded part; and bonding the parts together to form a clamping ring having an inward protruding stop edge at one of its ends. The embodiments further relate to a clamping ring formed from an extruded pipe part made of a cross-linked polymeric material and an injection molded annular part bonded together to form a unitary structure including an inward protruding stop edge at one of its ends.

A pipe adapter includes a first tubular element, a second tubular element, and an annular securing member disposed around and fixed to a second portion of the first tubular element. The annular securing member has a flange portion that contacts and secures the second tubular element axially relative to the first tubular element while also allowing the second tubular element to rotate relative to the first tubular element and the annular securing member. An annular sealing member is located around the first portion of the second tubular element to provide an axial seal along the adapter.

A pipe adapter includes a first tubular element, a second tubular element, and an annular securing member disposed around and fixed to a second portion of the first tubular element. The annular securing member has a flange portion that contacts and secures the second tubular element axially relative to the first tubular element while also allowing the second tubular element to rotate relative to the first tubular element and the annular securing member. An annular sealing member is located around the first portion of the second tubular element to provide an axial seal along the adapter.

A pipe connection comprises a connecting piece, a pipe and a clamping ring. The pipe and the clamping ring are made of a material having memory properties. An end of the pipe and the clamping ring have been reversibly expanded co-jointly and firmly and sealingly shrunk to the connecting piece by back shrinkage. Preferably the clamping ring is made from a cross-linked polyolefin by injection molding.

A pipe connection comprises a connecting piece, a pipe and a clamping ring. The pipe and the clamping ring are made of a material having memory properties. An end of the pipe and the clamping ring have been reversibly expanded co-jointly and firmly and sealingly shrunk to the connecting piece by back shrinkage. Preferably the clamping ring is made from a cross-linked polyolefin by injection molding.

The direct-current cable includes a conductive portion; and an insulating layer covering an outer periphery of the conductive portion, the insulating layer containing cross-linked base resin and inorganic filler, the base resin containing polyethylene, a BET specific surface area of the inorganic filler being greater than or equal to 5 m.sup.2/g and less than or equal to 150 m.sup.2/g, and a mean volume diameter of the inorganic filler being less than or equal to 1.0 μm, the mass ratio of the inorganic filler with respect to the base resin being greater than or equal to 0.001 and less than or equal to 0.05, and the cross-linked base resin being cross-linked by a cross-linking agent containing organic peroxide.

Aspects of the disclosure relate to manufacturing a balloon envelope for use in a stratospheric balloon system. For instance, a stream of polyethylene mixture us extruded. through an extruder in order to orient molecules of polymer chains of polyethylene and to provide an oriented film. The oriented film is passed through an electron beam and thereby crosslinking the polymer chains to provide a cross-linked film. The cross-linked film is heat sealed to form the balloon envelope