| 摘要 |
PURPOSE: An actuator for opening of butterfly valve is provided to reduce the maintenance cost by automatically opening and closing the butterfly valve with the restitution force of a spring and the differential pressure of the fluid. CONSTITUTION: An actuator for opening of butterfly valve comprises a bellows pipe(21), a link device(22), and a spring(24). The butterfly valve is divided with a partition(26) in to the twp spaces that a space where the fluid flows in from an upper side pipe(1a) of a butterfly valve and the space where the fluid flows in from a lower side pipe(1b) of the butterfly valve. The bellows pipe constructs can be shrunken newly according to the pressure difference between the fluid of upper and lower side pipe. One side of the link device is fixed at a valve shaft of the butterfly valve. The other end of the link device is fixed at the bellows pipe. The link device mutually transforms the linear motion according to the expansion of the bellows pipe and the rotational motion of the valve shaft. The spring gives the elastic force to the link device.
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