| 摘要 |
A controller comprises a power transmission means (11) for amplifying a forc e on a working shaft (6) and transmitting it to a valve rod (4), and a slow start means (12) for slowly moving the valve rod (4) upward. The slow start means (12) comprises a piston (8) vertically movable with respect to the working shaft (6), a pressure adjusting spring (44) disposed between a pressure adjusting spring seat (43) mounted on the working shaft (6) and the piston (8), a constantly opened communication passage (47) and an auxiliary communication passage (49) which establish communication between a pressure chamber (10) and an operating gas introduction chamber (27), a flow adjustin g valve (48) placed in the constantly opened communication passage (47), and a n on-off valve (50) placed in the auxiliary communication passage (49) adapted to open the communication passage (49) when the piston (8) is in its lowest position and to close the communication passage (49) when the piston (8) reaches an auxiliary communication passage block position elevated by a predetermined distance above the lowest position. |
