19th November, 2018 No Comments Conical Mills, Containment, Milling and Sizing
High Containment Bin-to-Bin Milling
When milling high potency materials (e.g. APIs), manufacturers require a dust-free and high containment solution which does not impede on process efficiency, such as throughput.
We have worked with many customers wanting to achieve a fully contained process; a popular solution is bin-to-bin milling. With the
incorporation of split valves in between the mill and the containers, the process is suitable up to OEB Level 3 or 4. With some upgrades or modifications to the split valve, then it can even be used for OEB Level 5 processes.
How It Works
In bin-to-bin milling, one container is positioned above the mill and the other below the mill (this is best achieved by using a hoist to manoeuvre the containers). The two split valves are placed either side of the mill, with the active half typically on the mill (due to it being the more complex and expensive half) and the passive half on the bin. The two halves of the valve then come together to create one vein.
Both split valves are then opened to release product (via gravity) into the mill and collect the product in the lower bin after it has been milled. The lower container must be fitted with a HEPA vent filter to aid powder flow through the mill and allow for the displacement of air. Once all product has been milled, the valves are then closed and the bins can be removed.
This high containment and dust-free process prevents the contents of the bins from being exposed to the environment without restricting throughput. The in-line nature of the process is optimal and compact and, while this system will not compete with the speed of transfer achieved using vacuum, the ease of bin changeover (either feeding or receiving container) can offer capacity advantages over other process methods.
Other Containment Options
We have focused on bin-to-bin milling here, but there are other options available for customers wanting to achieve high containment milling. This includes in-line vacuum transfer and milling inside an isolator; information on both is available here.