THE DOWNFLOW PRINCIPLE
The downflow air produced within the booth’s safe work zone area forces sterile air over the operator’s head and shoulders and downward towards the low level exhaust system. The downdraught prevents airborne dusts caused by weighing and dispensing operations rising into the operator’s breathing zone. The air forced downwards is extracted at low level into the booth’s filtration system where dust particles are contained at each level of filtration prior to being recirculated back into the booths’ air stream. The quality of the air within the booth is to ISO 14644-1:(2015) standards – Fed Std 209E.
Where the handling of toxic or harmful chemicals is required, Clean Air Solutions (Europe) Limited can provide a downflow booth with an exhaust to atmosphere extraction system. This type of downflow booth is recognised as a “single pass” airflow booth. Within this type of booth, weighing and dispensing of chemicals can be carried out in the normal way with the air supplied for the downflow coming from an additional fan located on the top plenum. The air is provided from either the booth surrounding area or from outside atmosphere. The low level exhaust airflow will not be recirculated but totally exhausted to atmosphere via suitable ductwork. The exhaust air can have H.E.P.A. or carbon filters fitted to aid control of emissions to atmosphere.
Working from a standard range of booth sizes a number of different configurations of booth design requirements can be achieved, namely:
- Low level ceiling heights
- Restricted access to booth location
- Special filtration needs
- Powder handling or tipping requirements
- Electrical wiring to client standards
- Materials of construction to suit process