Tek-Air has provided laboratory airflow control systems since our incorporation in 1983. The experience gained through the completion of hundreds of installations, for a wide variety of customers, is reflected in our design philosophy. Our design for each project is intended to embody the following key elements of this philosophy.
Be it airflow, space pressure, or face velocity; if a parameter is important enough to be controlled, it should be measured directly. Most competitors of fume hood controls measure sash open area only and then position a calibrated mechanical volume regulator (springs, bearings, and levers) to achieve volumetric flow control.
Tek-Air has designed fume hood controls for many specialized Hood applications using three different methods of control.
> Control based on the Velocity Measurement of the air drawn from the room through the open sash over our velocity sensor. Virtually any occurrence which affects the face velocity is detected by the sensor, even those which are caused by improper use of the hood. This measured face velocity is used as the parameter for the controller to change the flow in the duct to maintain face velocity set point.
> Control based on Sash Position with Flow Measurement is an enhanced version of what our competitors provide using the sash position to determine the volume set point for the hood. Tek-Airtakes accuracy and safety a step further by providing flow measurement in the fume hood duct where the volume set point is used as an input to the controller which is monitoring and controlling the duct air flow.
> Control based on Constant Volume or Two Position Control where a constant face velocity at the sash is not as critical as the two other methods. Even though this is simpler to accomplish with less hardware, Tek-Air still measures and controls the duct air flow, and provides face velocity monitors to alarm individuals when the hood is outside of acceptable limits.