| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a control device for a safety shut-off control valve, using a small number of solenoid valves and control circuits for actualizing continuous and reliable adjustment of the flow rate of fluid in a fluid circulation path, and safe and reliable shut-off in the event of failure of electrical power supply to the solenoid valves. <P>SOLUTION: A safety valve B is connected in series to the safety shut-off control valve in a fluid flow path. In the safety shut-off control valve A, a sealing valve is returned to a sealing position against a seat 8 by means of a return spring 18, and is controlled by a linear actuator 10 and a connecting rod 9 for continuous adjustment of the valve opening. The connecting rod 9 comprises two segments 12, 13 which are made from a ferromagnetic material and which are magnetically coupled to a magnetic coupling circuit 19 that is activated by a coil 32. While electric power is being supplied to the coil 32, a coil magnetic field maintains the connecting rod 9 segments 12, 13 coupled to one another. Once the power being supplied to an opening coil 32 is interrupted, the segments 12, 13 and the sealing valve return to the sealing position regardless of the position of the linear actuator 10. At the same time, a check valve 26 of the safety valve B is pushed back to the sealing position by a return spring 29. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
