Patent ID: 6994619

Claim:
A system for quickly controlling directional airflow into a fume hood having a vertical sash that is composed of: a. An optical sensing device mounted inside the fume hood with a light source that shines onto a reflective source and a sensing device that can sense the reflected light and determine the number of iterations of a repeated pattern on the reflective source and produce an output control signal that corresponds to sash movement to produce desired airflow into the fume hood b. A smart controller device that receives output control signals from the optical sensing device, said controller device having its own intelligence capable of producing a drive signal c. An actuation device capable of receiving the output signal from the controlling device to adjust an airflow control device such as a venturi valve or blade damper or some other device that modulates airflow into a duct or other airflow stream, d. Reflective tape mounted strategically on a fume hood sash(es) with proportional, repetitive, encoded patterns on it that can be read by the optical sensing device as the sash is opened or closed on the fume hood.