Pipeline system and method of assembly

A piping system, comprising in combination:

• plural lengths of pipe arranged in axially aligned relationship, each said pipe having axially spaced key engagement members adjacent the ends thereof;
• at least one conduit member providing transitions between respective said pipes, each said conduit member having axially spaced key engagement members adjacent the ends thereof;
• said key engagement members each being comprised of a ductile material;
• and
• plural segmented couplings embracing and secured to adjacent ends of said pipes and conduit members, each said coupling including:
• plural arcuate members each having an internal recess and each comprised of a substantially unfinished high-strength casting of a material having substantial ductility;
• a gasket positioned within said recess;
• securing means securing said arcuate members in encircling engagement with said pipes and conduit members, with said gasket in continuous sealing engagement with the ends of said pipes and said conduit members;
• and,
• plural axially spaced continuous arcuate keys integral with and extending inwardly of the inner periphery of each said arcuate member;
• said keys respectively being spaced axially correspondingly with said axially spaced engagement members of said pipes and said conduit members, and each being engaged with an engagement face of a said engagement members of said pipes and coupling members, said keys resisting relative axial movement between said pipes and said coupling members when said piping system is subjected to pressure loading;
• each said key having an unfinished engagement face produced in the casting thereof having an inversely pebbled surface which is engaged with a said engagement member;
• said engagement faces of said keys and said engagement members lying substantially radial and perpendicular to the axis of generation of the associated arcuate member;
• said inversely pebbled surface of each said key being capable of crushing down and cold working the juxtaposed radial face of the associated engagement member, to provide substantially uniform distribution of the stresses imposed upon said keys when said keys are subjected to axial loading.

A method of providing stress equilization in interconnections between conduit members of a conduit system when subjected to internal pressure loading, comprising the steps of:

• providing said conduit members with plural axially spaced engagement members adjacent to the ends thereof, and which each provide radially extending engagement faces, each said engagement member being comprised of a material of substantial ductility that is plastically deformable;
• arranging said conduit members with ends thereof in axial alignment with ends of adjacent conduit members;
• providing segmented couplings clamping adjacent ends of adjacent coupling members to each other;
• providing each said coupling with plural keys each having a radially extending engagement face for engagement with a said radially extending engagement face of said engagement members, and positioning said keys with said respective engagement faces of said keys and said engagement members in juxtaposition with each other;
• forming the segments of each said segmented coupling and the keys thereof as unitary substantially unfinished high-strength castings of a material having substantial ductility, and in which the radial faces of said keys, at least, have an inversely pebbled surface produced in the casting of said segments;
• and
• subjecting said conduit members and said couplings to oppositely acting axial loading forces to cause the inversely pebbled surface of the radial engagement faces of said keys to crush down and to cold work the juxtaposed radially extending engagement face of the juxtaposed engagement member, and to progressively produce substantially uniform distribution of the stresses imposed on the respective keys by progressive crushing down of said pebbled surfaces of said keys and cold working of the material comprising said engagement members.