| 摘要 |
PURPOSE:To enable an emergency valve closure with an economical device in an electrically operated valve which is reduced its rotation by an electric motor and has electrical control means by constructing same in such a manner in which the motor is actuated by a battery as a power source in case of an emergency so that the valve may be closed. CONSTITUTION:When a switch S1 is turned on when contact points CR1-1, CR1-2 of a relay CR1 are closed and contact points CR1-3, CR1-4 are opened, contact points CR2-2, CR2-3 of a relay CR2 are closed to cause the valve to be fully opened by a DC motor M. When a power stoppage occurs under such condition, said contact points CR1-1, CR1-2 are opened, and the contact points CR1-3, CR1-4 are closed. Then, even if the switch S1 is turned on, the relay CR2 is deenergized, and its contact points CR2-2, and CR2-3 are opened. And, the (+) side of the power source is inputted to a terminal M2 of the DC motor via a diode D and the contact point CR1-3, while the (-) side is inputted to a terminal M1 through a limit switch LSs, and the DC motor M is actuated to close the valve. |
