Challenges

As product volume can be very small it is essential that the sensor that measures sample temperature during processes can be introduced without jeopardizing the integrity thus very slim temperature sensors are needed. Ellab has developed a range of low temperature Teflon flexible sensors with a diameter of only 1.2 mm which can be easily inserted in the vial through the rubber stopper. For chamber validation a contact puck made of brass is available to secure paramount contact between the shelf and sensor ensuring correct readings.

The main challenges associated with monitoring freeze driers are the low temperatures and the low pressures present. The low pressures (around 5 microbar) restrict the ability to introduce cables into the chamber while still maintaining a good (high) vacuum. The vacuum is much more difficult to maintain than high pressure. However, the low temperatures used can make it difficult for some data loggers to function. TrackSense® Pro and the Pro battery can be used in temperatures down to –30°C. With the TrackSense® Pro-X, the logger can even go as low as –80°C. The unique battery management system, the design of the logger and Teflon flexible sensors makes them suitable for almost all freeze drier cycles, overcoming problems associated with the low temperatures.