The nutsche filter/dryer is a multipurpose piece of equipment that you can find in a wide range of industrial processes. Often found just downstream of a reactor or crystallizer, it has the important job of separating and isolating solids from a solvent. It has certainly come a long way since its beginning, when the nutsche filter design consisted of an open vessel that simply used suction to achieve separation. Modernization by Rosenmund started in the 1960’s, when the vessel design was enclosed for containment, enabling the introduction of pressure and agitation. The closed system further allowed for process control on parameters like temperature, pressure, pH, and agitation. In addition to expanding the unit’s operations, containment helped to protect operators from product environment as well as isolate the product from the atmosphere.
Nutsche filter/dryers are very flexible from a process standpoint; while they are typically used to reclaim solid products, there are rare instances when the solution is the desired end product (e.g. catalyst recovery, extraction, etc…). The modern day nutsche filter can perform a multitude of tasks including filling/charging, filtering, displacement washing, reslurry washing, smoothing, drying/cooling, and discharging. Combining the various filtration and drying steps in the same unit is a desirable function, especially for processing active pharmaceutical ingredients (API) and hazardous chemical compounds such as pesticides.
While the agitated nutsche filter/dryer maintains its original process functionality, the advancements made in recent decades have made it a critical component in contained batch processes for carrying out final and intermediate product isolation. Specialty batch-oriented applications like pharmaceutical and fine chemical production, dye, paint, and wastewater treatment commonly utilize agitated nutsche filter/dryers. This is because nutsche filter/dryers are suited to handle even the most hazardous products (flammable, toxic, corrosive, etc.).