Patent ID: 7114516

Claim:
A leak-detecting check valve that is characterized by being equipped with a valve casing that sets the circumference of a cylindrically shaped fluid channel; a main-valve sheet that is installed inside said valve casing; a main valve that has a large fluid-channel opening and that is equipped at its center with an ancillary-valve sheet, and that also is elastically energized toward the water-inlet side of said fluid channel and against said main-valve sheet by a main-valve spring; an ancillary valve that has a narrow fluid-channel opening, and that is elastically energized toward the water-inlet side of said fluid channel and against said ancillary-valve sheet by an ancillary-valve spring; a movable device that is installed nearer to the water-outlet side of said fluid channel than are said main valve and said ancillary valve, and moves in said fluid channel in conjunction with the movement of said main valve or said ancillary valve, as is the case; and a sensor that is implanted inside a valve casing on the water-outlet side of said fluid channel such that said sensor faces said fluid channel, so that said sensor senses said movable device when it moves to a specified location, thereby entering an area where sensing is possible, and transmits valve-movement-detection signals.