Potent powder sampling

When AstraZeneca needed to sample a potent product without disrupting production, it turned to Newson Gale for a solution

The need for representative samples plays a critical role in product verification, yet the sample also needs to be collected with consideration for operator and environment safety.With this in mind, Chris Roseveare, senior project manager with AstraZeneca, approached Newson Gale to provide it with a sampling system for a potent pharmaceutical powder, to be taken from the body of a rotary valve. As well as the need to collect a representative sample, it was important to prevent the powder from escaping into the atmosphere.

The finished specification of the sampler was going to involve a special design so AstraZeneca required a more flexible approach from the supplier of the system - this was never going to be an 'off the shelf' piece of equipment.

continual analysis

Newson Gale, based in Nottingham in the UK, is a supplier of plant and process safety equipment and represents a French manufacturer - Labocontrole - which manufactures powder sampling systems. Labocontrole has been a specialist in the sampling industry since 1988 and has wide experience in the food, pharmaceutical and chemical industries.

Continual analysis of bulk powder during AstraZeneca's production process could be a time-consuming and costly exercise if it is carried out manually. However, with a fully automated system, which can be timer controlled, the process of sampling the product throughout the batch can be achieved independently of the operator. Add to this a hygienic design with quick connections and you have a sampling system capable of taking accurate samples of process powder.

The basis of the PowControl sampler is a stainless steel (316) auger inside a probe, which is sealed with a removable PTFE bearing and is driven by an air motor. The auger pulls the powder along the probe and dispenses it into a bottle or bag. The sampling system can be connected to a filled vessel to sample static product or to a chute to sample falling product. Process connections can be flanged, tri-clamp or threaded.

On the standard sampler originally proposed, the air motor had a fixed hinge connection that opened to reveal the auger, which could then be removed for cleaning. However, AstraZeneca required a completely removable air motor. This would allow the operator to disconnect the sampler completely from the airlines, allowing all the product contact parts of the sampler to be easily removed for cleaning to prevent product cross-contamination.

The sampling system was installed in a glovebox; by separating the motor the number of items to be removed from the glovebox for cleaning was reduced, while also allowing a 'used' sampler to be quickly replaced with a clean one. To ease the disassembly in the glovebox, triclamp connections were chosen but designed in such a way that allowed both hands to be used for breaking the triclamp.

The coupling between the motor and auger was also designed so that if the motor is still running when uncoupled, gloved hands would not be damaged.

This eliminated an additional position switch in the original design, which would have isolated the power to the motor before the uncoupling was complete.

This simplified the equipment inside the glovebox, reducing both maintenance and cleaning work.