The Nano-16 twin-screw extruder from German equipment producer Leistritz (Nuremberg, Germany), integrated with a patent-pending micro-plunger feeder, is able to aid compound and masterbatch processors by simulating the continuous extrusion process for 20g and 100g batches. Applications include compounding, devolatilization, and reactive extrusion. It utilizes segmented screws and barrels, a stainless steel process section, and state-of-the art control and data acquisition.
Nano-16 twin-screw compounder features screw design with 1.2mm flight depth and a micro-plunger feeder.
Its free volume, directly related to the outer diameter/inner diameter (OD/ID) ratio, is a ratio of 1.18/a OD/ID. This permits a free volume of 0.9cc/diameter, claimed to be the lowest free volume available for a twin-screw extruder that is scalable to production class equipment.
The twin screws are starve fed, with the output rate determined by the feeders that meter material into the processing section. The extruder screw’s rpm is independent; this feature is said to help optimize compounding efficiencies. Previously, the unit was not offered with a feeding mechanism to effectively meter very small batches to the twin screw. Now it has a micro-plunger feeder that consists of a piston that slides within a stainless steel tube that is filled with a 20-100cc batch. After being mated at the bottom of the feed barrel, the piston is pushed upward by a drive screw to perform the feeding task at very low rates. Since the micro-plunger feeder is a positive displacement device, it can meter material in forms such as powders, granules, micro-pellets, pastes, or water based slurries.
The Nano-16 replicates the unit operations and shear imparting mechanisms of larger scale twin-screw extruders. The combination of a small free volume and precision low-rate feeding makes it, says Leistritz, the only extruder that can produce results that are scalable to production processing compounders. —[email protected]