Challenge

A large multi-station medical-device processing machine required stringent ventilation because of the hazardous substances used in several processes. The initial concept relied on roof extraction driven by a large centrifugal fan. This approach had a high energy demand and would continuously remove conditioned cleanroom air from the building. The objective was to develop an effective extraction system that achieved the required airflow at every process station while substantially reducing energy consumption.

Engineering Approach

Detailed mathematical models were developed to predict pressure losses, airflow distribution and heat transfer throughout the ventilation system. Because multiple process stations operated within an interconnected airflow network, a bespoke numerical solver was developed to evaluate different system configurations and optimise airflow throughout the machine. The resulting design was subsequently analysed in detail using CFD. Further development led to a distributed multi-filter system integrated within the machine, eliminating the requirement for external roof extraction and avoiding the associated loss of conditioned cleanroom air. Careful optimisation of the airflow network also allowed the system to operate with a significantly smaller fan than originally proposed. The system was manufactured and experimentally evaluated using local temperature, pressure and airflow measurements, including thermocouple, Pitot-tube and anemometer measurements. Final testing was then conducted on the completed machine.

Outcome

The completed system achieved the required airflow at every process station using a substantially smaller fan than originally proposed. Ventilation energy demand was reduced by more than 90%, while eliminating external extraction also avoided the continuous loss of conditioned cleanroom air. The resulting system was successfully tested on the completed machine and was significantly more cost-effective than the original proposal.