METHOD AND DEVICE FOR DIAGNOSING REMAINING SERVICE LIFE

• Main Authors: AKIYAMA MASARU, SAWARA KAZUYA, SHOTANI HITONOBU, TAMARU HIDEO, IKEDA SEIDO, NAGANO KENZO
• Format: Patent
• Language: English
• Published: 12.06.2001
• Edition: 7
• Subjects: BLASTING; DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OFGENERAL APPLICATION; HEAT EXCHANGE IN GENERAL; HEATING; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; LIGHTING; MEASURING; MECHANICAL ENGINEERING; PHYSICS; TESTING; TESTING STATIC OR DYNAMIC BALANCE OF MACHINES ORSTRUCTURES; TESTING STRUCTURES OR APPARATUS NOT OTHERWISE PROVIDED FOR; WEAPONS

PROBLEM TO BE SOLVED: To judge the remaining service life of an ORV until a crack occurs in a finned tube caused by accumulation of fatigue due to comparatively gradual and mechanical stress such as a bowing phenomenon occurring in association with generation of thermal stress in a long header tank. SOLUTION: Destructive inspection is performed to accurately measure how much remaining service life is left in the ORV from distortion slowly accumulated during a long period of ten years or more. At least one tube for heat exchange joined to the header tank is cut away from this tank along with a welding bead part, a welded part of the tube is bonded and fixed by putty to a fixture for testing, a vibration exciter is connected to an unbonded other end side of the tube to be tested for applying a required vibration until damage occurs in the tube near the welded part, it is counted until pressure of gas filled inside the tube reduces, and it is compared with a cycle until damage of a preset model or a predetermined fatigue occurs for measuring the remaining service life.