Large range of applications due to:
BUCHI Labortechnik offers a lab-bench Spray Dryer with glass cyclone and electrically conductive layer to prevent product losses in the cyclone. The near-mesh grain directly correlates with the diameter of the cyclone: a smaller dimension leads to a better separation of smaller particles. Based on general proportions described in literature and the manufacturing possibilities of the glass blower’s knowledge, a new type of cyclone has been developed and optimised. Furthermore, the product collection vessel was downscaled for small quantities and easy handling. The inner wall of the cyclone is coated with an electrically conductive layer to prevent any electrostatic charge of the product.
The glassware has to be cleaned after every trial, so an easy assembly and dissassembly is of crucial importance. With the one lever attachment of the spray cylinder, it is particularly easy to install the glass.
One of the reasons for the reproducibility of the Mini Spray Dryer B-290 is the durable and precise nozzle technology. Due to high cavitation the nozzle is even strengthen with a ruby stone at the outlet of the product and compressed gas.
The nozzle can be cooled with regular tap water. The water is supplied to the tip of the nozzle and flows in counter-current to the product. So the coldest water contacts the product at the latest possible point of the nozzle. Spraying of heat sensitive product is possible.
The nozzle has an integrated piston with cleaning needle to be pushed through the nozzle in case of clogging. The frequency can be selected between 2 and 30 seconds. Furthermore, a manual push-button enables the cleaning at any time.
Step 1 Heating: Heat the inlet air to the desired temperature (max. 220 °C)
Step 2 Droplet formation: Two-fluid nozzle
Step 3 Drying chamber: Conductive heat exchange between drying gas and sample droplets
Step 4 Particle collection: Cyclone technology
Step 5 Outlet filter: Collection of finest particles to protect the user and the environment
Step 6 Drying gas: Delivered by aspirator
With the Mini Spray Dryer B-290 or with the Nano Spray Dryer B-90 with the Inert Loop B-295 it is possible to spray with organic solvents without risk of explosion, because the system works under inert conditions.
The outlet temperature is depending on the parameters inlet temperature, sample feed rate, sample concentration and aspirator rate. A change in one of those parameters will either cause the outlet temperature increase or decrease.
The limiting factor is the peristaltic pump. So the sample still has to be pumpable. This will be possible with a viscosity up to 300 cps with the Mini Spray Dryer B-290 or 10 cps with the Nano Spray Dryer B-90.
Major differences: B-90 for smaller sample quantities (mL samples, mg powder amounts), higher yields up to 90% and smaller particle sizes (submicron) B-290 is the classical spray dryer for medium laboratory sample quantities at a wide range of applications (also viscous substances and fruit juices possible). Its scale-up is more straigthforward.