Design of Local Exhaust Hoods for HTF Smoke Extraction Fans

Design of Local Exhaust Hoods for HTF Smoke Extraction Fans

The design of the local exhaust hood is a crucial component of the overall design of an HTF smoke extraction fan. Why is this the case? An improperly designed exhaust hood can easily compromise the exhaust performance of the HTF smoke extraction fan. So, what principles should be followed when designing the local exhaust hood for an HTF smoke extraction fan? Please refer to the following analysis. 1. To confine harmful substances to as confined a space as possible, the local exhaust hood must enclose them as completely as possible or be positioned in close proximity. To facilitate capture and control, the intake area must be kept to a minimum. 2. The direction of the airflow from the exhaust duct should align as closely as possible with the direction of the contaminated airflow. 3. The flow of contaminated intake air must not pass through the breathing zone of personnel. In the design, the operator’s position and area of movement must be fully taken into account. 4. The extraction hood must be of simple construction and low cost, and installation and maintenance must be straightforward. 5. The configuration of the local exhaust system must be consistent with the manufacturing process to avoid affecting process operations. 6. Disturbances to airflow, cross-drafts and air currents must be avoided or minimised. Where possible, the intake flow should be directed towards