| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an airtightness monitoring system for an optical fiber compound overhead ground wire (OPGW) that enables the constant monitoring of the airtightness of an optical fiber compound overhead ground wire. <P>SOLUTION: The system includes: airtight metal pipes 23 and 25 for composing the optical fiber compound overhead ground wire; optical fiber junction boxes 4 A to 4 D each inside of which is rendered airtight; gas injecting means 7 for injecting gas 15 of constant pressure via one of the optical fiber junction boxes 4 A to 4 D; and pressure detecting means for measuring the pressure of the injected gas 15. When the pressure detecting means 5 A, 5 B, and 12 detect a reduced pressure, the system determines that the metal pipe 23 or 25 is damaged and that the airtightness of the OPGW 2 is lost. <P>COPYRIGHT: (C)2012,JPO&INPIT |
