Rib construction for large diameter pipe fittings

A ribbed pipe fitting to be used for connecting large-diameter corrugated pipe in underground burial applications, comprising:

• (a) a main section of pipe of twelve to sixty inches internal diameter having a generally cylindrical wall structure centered about an axis with a fluid-flow passageway extending therethrough;
• (b) a leg section of pipe seamlessly connected to said main section of pipe at an angle relative thereto, said leg section of pipe having a generally cylindrical wall structure centered about an axis with a fluid-flow passageway extending in fluid continuity with said fluid-flow passageway of said main pipe section;
• (c) said wall structure of said main section of pipe and said wall structure of said leg section of pipe each having a generally smooth inner circumferential surface and an exterior surface defined by a plurality of axially spaced circumferentially extending solid ribs, wherein said plurality of ribs on at least said main section of pipe are uniformly shaped and spaced throughout the entire length of said exterior surface thereof;
• (d) each of said ribs being defined by a generally flat crown portion and a pair of opposing radially extending circumferential sidewalls connecting said crown portion to an adjacent circumferentially extending waterway section of said wall structure;
• (e) said main pipe section and said leg section of pipe each including a terminal end comprising an integral bell structure that is seamlessly formed as a part of said wall structure thereto;
• (f) said main section of pipe and said leg section of pipe being formed integrally together as a single one-piece solid, seamless, modular unit through a process of rotationally molding;
• and
• (g) the dimensional profile of said wall structure of said main section of pipe and of said leg section of pipe being characterized by the following table:
• Angle θ
• 95-105 degrees
• Ratio B:C
• 1.80-2.80
• Ratio P:H
• 1.50-1.95
• Ratio H:D
• 0.04-0.09
• Ratio A:H
• 0.28-0.40
• Where “θ” is the angle at which said sidewalls of each of said ribs extend relative to the plane of said waterway section adjacent thereto;
• “B” is the base thickness of each of said ribs measured axially between said opposing sidewalls at the intersection thereof with said exterior surface of said wall structure at said waterway section;
• “C” is the crown thickness of each of said ribs measured axially between the tangential intersection of said opposing sidewalls with said crown portion thereof;
• “P” is the pitch or axial distance between adjacent said ribs measured at their center-points;
• “H” is the height of each of said ribs measured between said exterior surface at said waterway section and the outermost radial point of said rib;
• “D” is the inner diameter of said wall structure;
• and “A” is the average of the crown thickness “C” and base thickness “B” of each of said ribs.