Check valve and siphon tube assembly employing same

Claim 1

A check valve comprising: a generally tubular retaining member having a first end, a first inner diameter, a collar formed proximate said first end and a key extending from said collar to a location beyond said first end; a generally tubular body having an axis therethrough and including an inner surface having a second inner diameter that is slightly larger than said first inner diameter, said body further having a second end and a slot extending from said second end, said slot serving to receive said key when said collar abuts said second end; and a flapper valve formed from a portion of a tube having a third inner diameter that is substantially equal to said first inner diameter and having an outer diameter that is substantially equal to said second inner diameter, said valve having an outer surface that is symmetrical in plan view and is tapered between a first end and a second end, said valve further being generally triangular in side view so as to form a periphery between and including said first end and said second end, said outer surface extending a dimension such that when said valve is disposed in said body said outer surface forms a predetermined angle in side view relative to said axis and said periphery contacts said inner surface, said valve further including a slot-engaging member hingedly disposed in said slot adjacent said key such that said valve is movable between an open and a closed position, whereby when said valve is in said open position said outer surface is adjacent said inner surface and said third inner diameter lies on an imaginary cylindrical surface substantially corresponding to said first inner diameter such that fluid entering said retaining member and flowing in a direction through said body is capable of substantially unrestricted flow, and whereby when said valve is in said closed position said outer surface in side view lies at said predetermined angle relative to said axis and said periphery contacts and forms a seal with said inner surface such that when fluid flow is in an opposite direction it moves said valve to said closed position which substantially restricts fluid flow in said opposite direction.