New Leistritz feeder helps with compounding of tough additives

Twin-screw extruder manufacturer Leistritz this week introduced its new side feeder system LSB FLEXX, designed to help compounders avoid bridges, process interruptions or deviations in a formulation as they work with difficult additives. Leistritz (Nuremberg, Germany) introduced the new feeding system at this week’s Fakuma tradeshow in southern Germany, attended by MPW.
 
The manufacturer also brought news of the first sale and shipment of the company’s recently introduced ZSE180MAXX extruder, which left the firm’s Nuremberg facility at the end of September 2009. Because of a confidentiality agreement, neither the application nor the customer can be identified. The 30-tonne machine, which enables throughputs of up to 15 tonne/hr depending on the application, is the largest extruder Leistritz has ever produced.
 

Feeding badly flowing additives into the extrusion process can lead to bridges, process interruptions, or undesirable deviations in the formulation. Leistritz’s new answer to these problems is its LSB FLEXX side feeder. “Formerly there was a solid wall in the feed barrel of the side feeder. Now a silicone piece that replicates the original form can be inserted," explained Hubertus Schulte, promoted to CEO of the extruder manufacturer in January 2009. “So, when feeding badly flowing additives, practical advantages arise for the compounder” with the new feeder, he said.
 
The outside wall of the feed barrel on the new system is notched. A pneumatically activated roll oscillates along those notches. The linear movement can be turned on and off via the extruder control. The wall is set in motion by the linear movement. This combination of movements helps prevent bridging in the feed barrel, and breaks apart any bridges before they become problematic. Leistritz officials say the feeder is easier to clean than established anti-bridging systems that depend on mechanical stirring devices, vibrator motors, or wipers, and thus keeps material changeover times to a minimum. —[email protected]