Patent ID: 7874307

Claim:
A method for installing a check valve in a pipe coupling: (a) providing a conventional plastic pipe coupling having an inner surface and an entirely uniform inner diameter except for a centrally disposed inner ridge, said inner ridge having an upstream edge and an opposite downstream edge; (b) providing a pipe which is shaped and dimensioned to be received by said pipe coupling; (c) providing a check valve including; a body; a valve plate rotatably connected to said body; said valve plate biased to a closed position; said check valve shaped and dimensioned to be installable inside said pipe coupling; when in said closed position said check valve having a thickness, said diameter being at least three times said thickness; said body having a circumference; a circular seal disposed around said circumference; said check valve having a first central axis; said valve plate having a second central axis; said second central axis offset from said first central axis; said check valve having a diameter such that when said check valve is installed in said pipe coupling said check valve abuts said inner surface of said pipe coupling; (d) providing glue; (e) sliding said check valve into said entirely uniform inner diameter portion of said pipe coupling so that said check valve is completely inside said pipe coupling and said check valve abuts said inner surface and said inner ridge of said pipe coupling such that said circular seal abuts both said upstream edge of said inner ridge and said inner surface of said pipe coupling; and, (f) using said glue to glue said pipe in place in said pipe coupling so that said pipe abuts said check valve.