Patent ID: 8502165

Claim:
An ultraviolet sterilizer having a watertight function, comprising: a housing having an inlet through which ballast water is drawn into the housing, and an outlet through which the ballast water is discharged from the housing after the ballast water has been sterilized; an ultraviolet sterilization unit provided in the housing, the ultraviolet sterilization unit comprising an ultraviolet lamp applying ultraviolet rays to the ballast water to sterilize the ballast water; a cap supporting an end of the ultraviolet sterilization unit, the cap being watertightly coupled to the housing, wherein the cap has an air inlet hole formed through a predetermined portion of the cap; and a pressure controller connected to the predetermined portion of the cap, the pressure controller supplying air into the cap such that an internal pressure of the cap is maintained higher than an external pressure thereof, and the pressure controller includes a connector coupled to the air inlet hole, an air supply tube connected at a first end thereof to the connector, an air supply unit connected to a second end of the air supply tube, the air supply unit generating air pressure to supply air into the air supply tube, and a backflow prevention valve provided at a predetermined position in the air supply tube to prevent ballast water from flowing backwards from the cap towards the air supply unit.