Abstract: A FES assembly for use with a drainage pip is described herein. The FES assembly includes an inlet head wall portion, a tapered midsection coupled to the flared end portion, the tapered midsection extending from the inlet head wall portion to a flared end section. The inlet head wall portion defining a base wall spacing and coupling first and second lateral walls, a partially circular portion defined by the first and second lateral walls, and a coupling base portion extending along the base wall. First and second folding hinge arms are hingedly coupled to the first and second lateral walls, wherein the first and second folding hinge arms define first and second arced surfaces. The first and second hinge arms extend between an open position and a closed position, wherein in the closed position, the first and second arced surface align with the partially circular portion to define a portion of a circle greater than the partially circular portion.

Abstract: High flow capacity corrugated coilable dual wall plastic pipe having improved longitudinal flexibility and a bend radius sufficient to permit coiling and plowing of such pipe into the ground using automated installation equipment. The coilable dual wall pipe has an outer corrugated wall formed of a thermoplastic material such as high density polyethylene, and an inner smooth wall formed of a different more flexible and resilient thermo-bondable material that has an enhanced strain capacity and lower modulus of elasticity. The inner wall material also has enhanced mechanical properties which generally improve processing and help prevent excessive drag and tearing of the liner material during the manufacturing process.

Abstract: High flow capacity corrugated coilable dual wall plastic pipe having improved longitudinal flexibility and a bend radius sufficient to permit coiling and plowing of such pipe into the ground using automated installation equipment. The coilable dual wall pipe has an outer corrugated wall formed of a thermoplastic material such as high density polyethylene, and an inner smooth wall formed of a different more flexible and resilient thermo-bondable material that has an enhanced strain capacity and lower modulus of elasticity. The inner wall material also has enhanced mechanical properties which generally improve processing and help prevent excessive drag and tearing of the liner material during the manufacturing process.

Abstract: A corrugated pipe 2 has a plurality of corrugation structures 10, 12 positioned adjacent one another. The corrugation structures 10, 12 comprise an inner cylindrical wall 22, two annular wall portions 28, 32 that extend outwardly from the inner cylindrical wall 22, and a bowed annular wall portion 40 that is connected to the outer ends 36, 38 of the two annular wall portions 28, 32. The corrugation structure 10, 12 includes a centroid 48, 49 and at least a portion of the inner surface 50 of the bowed wall portion 40 has a radius R1 centered on the centroid 48, 49 and at least a portion of the outer surface 52 of the bowed wall portion 40 has a radius R2 centered on the centroid 48, 49. The cavity 56 defined by the corrugation structure 10, 12 has an inner surface with an inner radius R1, R3 that is equal to or greater than one half the thickness T1 of the inner cylindrical wall 22.

Abstract: A corrugation has a radially inner wall circumferentially surrounding an axis. The inner wall defines an inner cavity configured to conduct a liquid axially through the inner cavity. A radially outer wall of the corrugation overlies the inner wall. The outer wall adjoins the inner wall so as to form a closed outer cavity bounded by the inner and outer walls and separated from the inner cavity by the inner wall. The inner wall has at least one opening providing fluid communication between the inner and outer cavities for the corrugation to serve as a reservoir for the liquid.

Abstract: A corrugated pipe (2) has a plurality of corrugation structures (10, 12) positioned adjacent one another. The corrugation structures (10, 12) comprise an inner cylindrical wall (22), two annular wall portions (28, 32) that extend outwardly from the inner cylindrical wall (22), and a bowed annular wall portion (40) that is connected to the outer ends (36, 38) of the two annular wall portions (28, 32). The corrugation structure (10, 12) includes a centroid (48, 49) and at least a portion of the inner surface (50) of the bowed wall portion (40) has a radius R1 centered on the centroid (48, 49) and at least a portion of the outer surface (52) of the bowed wall portion (40) has a radius and at least R2 centered on the centroid (48, 49). The cavity (56) defined by the corrugation structure (10, 12) has an inner surface with an inner radius R2 centered on the centroid (48, 49).

Abstract: A corrugated pipe (2) has a plurality of corrugation structures (10, 12) positioned adjacent one another. The corrugation structures (10, 12) comprise an inner cylindrical wall (22), two annular wall portions (28, 32) that extend outwardly from the inner cylindrical wall (22), and a bowed annular wall portion (40) that is connected to the outer ends (36, 38) of the two annular wall portions (28, 32). The corrugation structure (10, 12) includes a centroid (48, 49) and at least a portion of the inner surface (50) of the bowed wall portion (40) has a radius R1 centered on the centroid (48, 49) and at least a portion of the outer surface (52) of the bowed wall portion (40) has a radius and at least R2 centered on the centroid (48, 49). The cavity (56) defined by the corrugation structure (10, 12) has an inner surface with an inner radius R2 centered on the centroid (48, 49).

Abstract: A corrugation has a radially inner wall circumferentially surrounding an axis. The inner wall defines an inner cavity configured to conduct a liquid axially through the inner cavity. A radially outer wall of the corrugation overlies the inner wall. The outer wall adjoins the inner wall so as to form a closed outer cavity bounded by the inner and outer walls and separated from the inner cavity by the inner wall. The inner wall has at least one opening providing fluid communication between the inner and outer cavities for the corrugation to serve as a reservoir for the liquid.

Abstract: A pipe structure includes an annular corrugation centered on an axis. The corrugation has a cylindrical liner centered on the axis, two annular sidewalls extending radially outward from axially opposite ends of the liner, and an annular crown extending axially between radially outer ends of the sidewalls. An annular cavity is centered on the axis and is bounded by the liner, the sidewalls and the crown. A structural filler is contained within the cavity.

Abstract: A pipe structure includes an annular corrugation centered on an axis. The corrugation has a cylindrical liner centered on the axis, two annular sidewalls extending radially outward from axially opposite ends of the liner, and an annular crown extending axially between radially outer ends of the sidewalls. An annular cavity is centered on the axis and is bounded by the liner, the sidewalls and the crown. A structural filler is contained within the cavity.