Pneumatic screening and conveying of pharmaceutical powders

Howorth Air Technology integrates vacuum conveying screener with DownFlow Booth and Containment Isolator to deliver contained screening of APIs

For over 150 years, the Howorth name has been synonymous with innovation in creating safe, clean working environments. Known today as Howorth Air Technology, the company engineers a range of powder containment solutions, aseptic systems and ultra-clean air filtration ventilation systems for medical, pharmaceutical and other industries. Based in the U.K with offices in the U.S.A. and representation in Europe and Asia, Howorth delivers high-quality equipment to clients throughout Europe, Asia and the Americas. The company is customer focused, providing bespoke products and turnkey systems to meet the requirements of clean rooms, operating theatres or pharmaceutical manufacturing facilities.

When a leading global pharmaceutical company sought multiple customized solutions as part of a new production facility, Howorth combined its expertise with Russell Finex – a global manufacturer of pharmaceutical screening and filtration equipment. The customer previously held concerns about operator exposure during the processing of APIs, as traditional powder screening machines often do not provide the levels of containment required to ensure operator safety. Two systems for pneumatic screening and conveying of pharma powders were required to guarantee containment during sieving in two key production areas.

Paul Stanway, Business Development Manager at Howorth Air Technology, said, “Firstly, the customer required a DownFlow Containment Booth, incorporating various process operations such as blending, weighing and sieving. Secondly, a containment isolator, also known as a glove box, was required to sieve and weigh APIs in a fully-contained environment.”

Howorth’s WORKSAFE™ containment booths provide high levels of operator protection, ergonomically and hygienically designed to allow multiple process operations to be carried out. For this specific process, pharmaceutical powders would be pre-weighed, transferred into a hopper then vacuum-conveyed into an IBC via a sieving system ensuring the product is screened to guarantee a consistent particle size and remove oversize and foreign contamination.

Howorth has a wealth of experience in combining containment technology with other specialist equipment. On this occasion, a Russell Compact Airswept Sieve™ was recommended as the integrated powder screening system of choice. This vacuum conveying sieve combines industry-proven Russell Compact Sieve® technology with vacuum conveying lines, ensuring powders can be check-screened in one dust-tight operation. The sieving unit is also quick and easy to dismantle, reducing downtime between processes.

As well as DownFlow Booths, Howorth engineers high containment isolators to provide fully-contained environments for API handling. Howorth isolator systems combine containment to nanogram levels with integrated equipment to provide maximum production, ergonomic and maintenance efficiency. For the containment isolator process, APIs would be loaded into the isolator utilizing a drum-loading chamber with the product vacuum-conveyed and sieved, then deposited into the same IBC as described previously. On this occasion, a hybrid sieving system was engineered, combining a Russell Compact Airswept Sieve™ with the Russell Compact Airlock Sieve™ clamping system.

This custom-built containment powder screener provides all the benefits of vacuum-conveying sieve technology with the patented TLI (twist, lock and inflate) airlock clamping system –  designed to provide effortless operation, ideal for pharmaceutical sieving in a glove box. An additional inlet was also incorporated to allow for manual scoop-feeding of powders on a smaller scale. To further improve usability, Howorth’s glove boxes have an integrated clean-in-place system with hygienic spray balls and a wash hose to allow easy wash-down of equipment after use.

The user-friendly Russell Compact Airlock Sieve™ TLI (twist, lock and inflate) clamping system provides effortless operation whilst maximizing screening performance. The system is easy to use, and requires significantly less space than alternative clamping methods. Simply place the component parts into the base and locate them by twisting and locking the lid. An inflatable seal then locks the components in place. This reduces the dust and improves operators’ health and safety, providing OEL 5 containment (less than 1µg/m3). The system also means these units are quick and easy to dismantle in areas of limited space, such as containment isolators.

Mr Stanway continued, “We chose to work with Russell Finex on this project because of the wide range of compact pharmaceutical screening equipment available, including the Russell Compact Airlock Sieve which provides a significant ergonomic advantage when operated and maintained within the constraints of a Containment Isolator. Support provided by Russell Finex during the design and mock-up phase was also invaluable. When providing premium custom-built solutions such as this, it is imperative the equipment we integrate is of a high quality, operator-friendly and versatile to meet specific functions and environments.”

With a range of sizes and configurations available, this range of pneumatic pharmaceutical sieving equipment ideally suited to integration inside areas of limited room such as pharmaceutical downflow containment booths and containment isolators. These compact screeners provide accurate, high-capacity powder screening at less than half the size of traditional sieving units. Included in this range is the Russell Compact Airswept Sieve™. This vacuum conveying sieve improves production capacity – by up to four times compared to standard vacuum conveying sieves. Dust-tight operation reduces the risk of product inhalation, and its easy-clean and strip down design ensures production downtime is kept to a minimum.