The investment in new production technology at its Centre of Excellence led a manufacturer of pharmaceutical products to seek supplier support in the provision of a containment system capable of delivering operator protection from hazardous airborne particles generated during manual product transfer.
The requirement was for a dispensary downflow booth designed to support dispensing and weighing out of active/excipient pharmaceutical powders with the ability to meet low occupational exposure limit (OEL) levels during drum tip, invert, dock, mill and IBC transfer, (all fully interlocked with client MES).
In line with a comprehensive user requirement specification, the pharmaceutical manufacturer requested Hosokawa Micron to develop a bespoke, GMP design, multi-functional, dispensary weigh booth.
Downflow booth
Hosokawa engineers designed a bespoke, 5 m wide, recirculation, dispensing downflow booth suitable for the handling of OEB3 compounds with a time-weighted average less for process operator level (OEL) less than 0.100 mg/m3 (<10 µg/m3) with the addition of a high containment barrier screen.
The booth, the company said, consistently meets these target OELs in an 8 hr period to deliver a high level of operator protection. Full on-site OEL testing was undertaken by Hosokawa Micron’s industrial chemist in accordance with ISPE Guidelines and SAT tests validates these figures.
Hosokawa revealed that the downflow booth has been designed with an increased safe working zone of 2 m. Customer requirements for all operations to be on one level and with space and height constraints due to location of structural beams and room layout.
The downflow booth is fitted with a temperature cooling package and attention to handling equipment noise levels to provide a more comfortable working environment for operators.
The individual units are designed for quiet operation (less than 70 dba).
The two drum inverters will be used for dispensing larger excipients: each drum inverted equipped with a funnel, butterfly valve and valve outlet chute. The 5d screen is used during the opening of raw material drums to limit operator exposure.
Raw materials for dispensing into IBCs are presented in a range of multiple drum sizes to be discharged into an IBC using a drum tipper and post hoist inverter.
Space restrictions determined that drums be lifted and inverted using either the drum tipper or post hoist to allow for the 120⁰ or 180⁰ rotation required to invert for discharge. If the raw material requires milling the material enters the IBC via the mill, which is part of the dispensing train but which only has the impellor and screen fitted when required.
Safety, accuracy, repeatability and low maintenance
The design also features a vacuum lifter used to lift a raw material drum off the pallet and place the drum on the inverter where it is clamped into position and fitted with drum discharge cones for easy, dust-free discharge of drum contents. Drums are then lifted and lowered onto the mill and docked and locked into position for discharge.
The drum tipper and inverter provide the ultimate method for safe lifting for reasons of safety, accuracy, repeatability and low maintenance.
A downward inflating packing head located below the mill outlet inflates against the IBC inlet to ensure closed transfer of materials from mill to IBC. A mill frame with combined IBC guide rails ensures the IBC is perfectly docked for filling prevented product egress which may present a health and safety hazard.
The customer commented: “We have worked with Hosokawa on similar installations and always find them easy to work with, taking time and effort to work closely with our in-house team and other suppliers to ensure an optimum, holistic solution.
“The input from Hosokawa’s experienced engineers is invaluable, not least in the early design stages with physical and visual mock ups that reassure all members of our team including our H & S and maintenance managers, that we have the best design possible for the task.”
Carl Emsley of Hosokawa Micron, said: “A complete wooden mock-up of the installation was built in our workshops to enable the internal layout of equipment to be ergonomically assessed for optimum positioning.”
Emsley said the team also undertook a computational fluid dynamics simulation to show air flow distribution/movement to ensure positioning of both equipment and personnel did not compromise efficiency of the booth.
“The use of CFD technology allows layout changes to be made at early design stage – not only speeding up the design and build processing but also eliminating costly design errors. This was particularly beneficial when working with several 3rd party equipment suppliers on this challenging project,” he concluded.
