| 摘要 |
PROBLEM TO BE SOLVED: To prevent the bite-in of particulate matters into a gap between an on-off valve and an internal face of piping.SOLUTION: A switchgear 10 comprises: an on-off valve 11 which is arranged in piping 3 into which particulate matters P are supplied, and movable between an opening position which permits the passage of the particulate matters P and a closing position which prohibits the passage of the particulate matters P; a fluid pressure actuator 20 which has two pressure chambers 21a, 21b therein, and drives the on-off valve by the pressure of fluids supplied to the pressure chambers 21a, 21b; and a fluid supply part 30 which supplies the fluids to the two pressure chambers 21a, 21b. The fluid pressure actuator 20 drives the on-off valve to the opening position when the fluid is supplied to the first pressure chamber 21a, and drives the on-off valve to the closing position when the fluid is supplied to the second pressure chamber 21b. The pressure of the fluid supplied to the second pressure chamber 21b is lower than the pressure of the fluid supplied to the first pressure chamber 21a. |
