Fume hood apparatus has control device connected to sensor, to perform necessary comparison calculations, and optical relative indicator with display of average air flow rate per unit time in relation to preset reference values

摘要

The apparatus has chemical fume hood provided with an exhaust air duct with suction fan communicated with enclosure. A throttle valve is provided in upstream of suction fan of exhaust duct. The measuring sensors are arranged to position a sash, cross-slide or throttle valve. The control device for throttle valve is connected to sensor, to perform necessary comparison calculations. The optical relative indicator (11) is provided with display of average air flow rate per unit time in relation to preset reference values. An independent claim is included for method for controlling throttle valve in exhaust air duct.