Automatic Sash Positioning System
Overview
The New Tech ASPS, installed as a retrofit or on new installations, will enhance your Lab VAV system by closing the fume hood sash when the hood is not in active use (i.e. when the user is not standing at the hood face). The result is that your hoods will be operating at the minimum exhaust volume nearly all of the time during the work day, and 100% of the time on evenings and weekends.
The ASPS can be operated in Auto or Push Button mode. These modes refer to the opening of the hood sash. Closing is always automatic. When the user approaches the hood, a presence sensor - or the push button- initiates the sash rising at about 1 foot per second (adjustable). We generally set the hoods to open to a height of 18", but you can specify the desired height. The user can manually adjust the sash height quite easily.
When the user leaves the hood face, and after an adjustable time delay, the sash closes, again at an adjustable rate. If the sash safety eye 'sees' an obstruction, such as a piece of glass, the pneumatic pressure closing the sash will be halted prior to the sash touching the obstruction. An alarm light will be activated. The alarm is deactivated when the sash goes back up again, either because of presence or from pushing the button, depending on the mode of operation.
Where installed as a retrofit, the installation results in an increase of physical plant capacity, possibly allowing for the addition of fume hoods.
In new construction the sizing of the HVAC system equipment can be reduced, right-sizing it for the reduced demand for heated and cooled air.