Water sterilization system

Claim 1

A water sterilization system which includes a sterilizer comprising an elongated cylindrical housing of a plastic normally degraded by ultraviolet light, having opposing ends and an inside wall, said inside wall being covered with a protective liner to expose an ultraviolet light-reflecting inner surface; a hollow, open-ended cylindrical sleeve of a material transmitting ultraviolet light, extending coaxially within said housing, and having an outer surface spaced from said inner surface to form an annular water chamber; closure means affixed at each of said opposing ends for sealing said chamber, including a plastic insert plug having an inside surface lined with a protective cover to expose an ultraviolet light-reflecting interior surface; water inlet and outlet conduits in communication with said chamber and adapted to connect to a central water supply; a UV electric lamp enclosed within said sleeve, said lamp carrying terminals to receive electric power from leads fed into said sleeve; together with a lamp power supply connected electrically to said lamp terminals and adapted to connect to an AC power line; in combination with fail safe control mechanism comprising a normally closed water valve in said inlet or outlet conduit; and a series electrical circuit adapted to be AC line-powered and including a photoresistor adapted to receive light from said lamp, the resistance of said photoresistor decreasing as the intensity of the light increases, and a stallable electric motor coupled mechanically to said water valve to hold said valve open so long as said photoresistor receives sufficient light than an operating voltage appears across said motor; whereby UV-induced degradation of the plastic wetted surfaces and contamination of the water by the degradation products are avoided.