| 摘要 |
A system for optimizing the flow of air through a fume hood by dynamically controlling the air flow to provide a stable vortex in the vortex chamber of the hood, the optimum condition for minimizing backflow of fume-laden air through the hood doorway. A highly-sensitive pressure sensor disposed at a critical location in the vortex chamber sidewall senses minute variations in vortex pressure indicative of turbulence and sends signals via a transducer to an analog controller which uses proportional integral and adaptive gain algorithms to formulate output signals to an actuator which adjusts dampers in the hood to change the airflow into the vortex. The system operates in feedback mode and seeks a minimum in the amplitude of the sidewall pressure variations, indicating that turbulence has been eliminated and that a stable vortex exists. The pressure sensor signals can also be directed to an alarm to signal an off-standard and potentially dangerous condition.
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