Knighton had been involved previously on several construction projects there, and had experience with several different types of fume exhaust systems, including mixed-flow impeller exhaust fan systems.
Direct drive mixed-flow impeller systems operate on a unique principle of diluting contaminated exhaust air with unconditioned, outside ambient air via a bypass mixing plenum and bypass dampers.
He credits the use of mixed-flow impeller technology.
Two low profile mixed-flow impeller systems (Tri-Stack systems from Strobic Air Corp.
Tepfer placed a great deal of confidence in Knighton's knowledge of the facility's requirements for noise and vibration and the possible exhaust system solutions: "He had done a lot of work for us and had actually been describing mixed-flow impeller exhaust fan technology in comparison to other technologies.
They felt this system and approach were too noisy for their state-of-the-art research facility and ruled against the centrifugal exhaust fan approach in favor of mixed-flow impeller systems from Strobic Air Corporation, Harleysville, PA (www.
The exhaust system is based on two low-profile mixed-flow impeller systems.
They chose a mixed-flow impeller systems which, even with the massive airflow produced during initial testing, kept noise at a minimum
Mixed-flow impeller systems also reduce noise, use less energy, and provide enhanced performance with faster payback over conventional laboratory fume hood exhaust systems.
Mixed-flow impeller systems are available with a variety of accessories that add value, reduce noise, and/or lower energy costs substantially.
In high head applications, mixed-flow impellers
Pumps with mixed-flow impellers
develop pressure partly by centrifugal force and partly by the lift of the impeller vanes acting on the liquid.