| 摘要 |
A vacuum actuated valve assembly includes a valve body housing a butterfly valve configured to be connected to a vapor containing fluid source having a static pressure; a linear rack and pinion assembly; an externally exhausted pneumatic actuator having a body with a first end and a second end, an internal piston, an external piston rod shaft having a third end away from the body of the actuator, and a spring located over the external piston rod shaft and fitted in between the second end and a stopper near the third end. The externally exhausted pneumatic actuator is configured to be operated by the static pressure of the vapor in the fluid source. The rack and pinion assembly is coupled to the third end of the external piston rod shaft, and configured to operate the butterfly valve.
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