| 摘要 |
PURPOSE:To shut supply gas off securely through simple constitution during a fault by incorporating a shut-off valve device in a gas meter. CONSTITUTION:When supply gas should be shut off in case of a fault or emergency, a one-shot current is fed to the coil 25 of an electromagnet 24, a perma- nent magnet 28 loses the attractive force of an iron core 29 by the reverse magnetic field of the permanent magnet 28, and a valve body 23 is separated by the electromagnet 24 by the repulsive force of a separating spring 31; and the valve body 23 abuts on a valve seat 22 to close a valve device, and the supply gas is shut off to secure safety. In this case, upstream pressure, i.e. original pressure operates on the valve body 23 in a valve closing direction, so the valve is closed by both the original pressure operating on the valve body 23 and spring 31. Therefore, enough force to close the valve device is obtained. |
