A submersible robot for hazardous environment

This paper presents an overview of a robot designed for operation in a Class I Division 1 Group hazardous environment. The robot will be used to inspect above ground storage tanks (AST) in accordance with API 653 guidelines. The system discussed here is purged and pressurized with nitrogen gas to eliminate all oxygen content inside the electrical enclosures. The sensors in contact with the hazardous medium are energy limited by zener barriers so if a failure occurs, the electrical energy released will not be sufficient to ignite the combustible fluid. Materials were selected for their electrostatic dissipation and low sparking characteristics. To assist with the industry acceptance of the robot the design has been reviewed by Factory Mutual and verification tests have been conducted under their guidance.