Critical point drying is a key process in preparation technology for gently removing liquids from sensitive samples without surface-altering forces such as surface tension or capillary effects. The transition of a liquid into the supercritical state cancels out these forces so that structures remain in their original form. This process is therefore an essential part of high-quality sample preparation for scanning electron microscopy.

The K 850 critical point dryer from EMITECH was specially developed for SEM sample preparation and for drying silicon wafers and MEMS and combines high versatility with ease of use. The vertically designed pressure chamber system provides a clear view of the liquid meniscus throughout the process through an integrated glass viewing window, allowing precise control of the transition. The chamber has a diameter of 32 mm and a height of 47 mm; it is filled from above and emptied from below and is additionally shielded by a safety guard. A magnetic stirrer in the chamber base supports the even distribution of the liquid.

For stable process conditions, the K 850 has an adiabatic cooling system using liquid CO₂ and a thermoelectric heater. Temperature and pressure are continuously monitored, while thermal overheating protection and a safety cut-out switch in the event of overpressure ensure a high level of operational safety. The pressure is relieved via a finely adjustable needle valve, which enables controlled pressure reduction.

All in all, the EMITECH K 850 offers a reliable, user-friendly and easy-to-understand solution for demanding drying applications in material and microstructure analysis.