| 摘要 |
<p>A device for controlling flow through a passageway consists of a piston (5) having one face exposed to the fluid in the path. This face of the piston forms part of a venturi disposed in the passageway such that the conduit has a cross-sectional area that decreases and then increases. The piston is movably mounted so that the piston may move in a direction transverse to the flow so as to narrow or widen the venturi. First and second static pressure ports measure the static pressure, the first port (23) being located at a relatively wide portion of the conduit, and the second port (24) being located at a narrower portion of the conduit. A transducer (32) determines the position of the piston. An actuator (35) adjusts the position of the piston (5) based on the static pressure measured at the first and second static pressure ports.</p> |
