Patent ID: 7410146

Claim:
A drain valve, comprising: a restrictor cap, comprising: a flow valve having a flow valve top mated with a flow valve base that contains at least one flow valve aperture just below the flow valve top; and a moveable control ring having a control ring aperture slidably surrounding the flow valve, and a control ring top mated to a control ring base, the control ring top remaining at all times below the flow valve top, the control ring base having at least one control ring protrusion; and a stationary base ring for receiving the moveable control ring to control operation of the drain valve, the base ring surrounding at least the control ring protrusion, the base ring further being sealed around the bottom portion of the flow valve base and having at least one interior channel for containing the control ring protrusion, wherein the channel protrudes partially into an interior surface of the stationary base ring and an exterior surface of the stationary base ring is a continuous, unbroken surface, the channel being constructed and arranged to rotationally receive the control ring protrusion such that rotational movement of the control ring causes the protrusions to rotate within the channel to thereby open or close the drain valve.