| 摘要 |
PROBLEM TO BE SOLVED: To enhance reliability in conducting communication within an explosion-proof area, by disposing a radio device in a pressure withstanding explosion-proof case in an electrically floating condition, and disposing an antenna having a completely explosion-proof structure on the external part of the pressure withstanding explosion-proof case. SOLUTION: An antenna 6 is mounted on a pressure withstanding explosion- proof case 1 without covered with an antenna radome or the like, and the shield part of the antenna 6 is connected to the pressure withstanding explosion- proof case 1 and to the frame ground 5 of the pressure withstanding explosion- proof case 1. A radio 2 is disposed in the pressure withstanding explosion-proof case 1 under such a condition as to be insulated from the pressure withstanding explosion-proof case 1. An antenna barrier 8 is added at the position at which the core wire of the coaxial cable of the antenna 6 protruding to the external atmosphere and the radio 2 are connected to form a safety explosion-proof structure and separate the radio 2 and the antenna 6 in a DC manner. It is thus possible to prevent the radio 2 from being damaged by thunder surges, thereby increasing reliability in conducing communication.
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