| 摘要 |
PROBLEM TO BE SOLVED: To facilitate a process accuracy management and an assembly of an explosion-proof container used for an electric-pneumatic converter. SOLUTION: The electric-pneumatic converter is formed by combining an explosion-proof container 1 which self-contains a motor 6, an electric circuit board 3, a current conversion unit 4 and a terminal base and a water-proof container 2 which self-contains a pneumatic conversion unit 9 and a pilot relay 10. A rotation shaft 30 for transmitting a rotation of the motor 6 to the pneumatic conversion unit 9 is provided on a shaft hole communicating with the explosion-proof container and an air passage axially penetrating through the rotation shaft 30 and self-containing a frame arrester satisfying a requirement of explosion-protection is provided in the rotation shaft 30. An air piping for introducing air pressure outputted from a pilot relay 10 is connected to one end of the air passage and an air piping for introducing the air pressure to a pressure sensor is connected to the other end thereof. A space and a length satisfying the requirement of the explosion-protection are provided between the air piping and the shaft hole.
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