K 2013: Solutions for the metering of blowing agents and additives in extrusion processes

With over 3,000 exhibitors, K in 2013 will be the most important trade show for the plastics and rubber industry. LEWA will also be there to present its technologies for the metering of blowing agents and additives in extrusion processes. One such solution is the LEWA ecofoam which conveys a volume of blowing agent proportional to the speed of the extruder. With this complete system that includes an ecoflow metering pump, measurement and control technology, blowing agents such as CO2, propane, butane, halogenated hydrocarbons, and pentane can be precisely metered into the plastic melt of an extrusion process to produce foam packaging or insulating material.

At short intervals, the LEWA smart control compares the signal from the flow meter to the control signal and adjusts the flow rate of the blowing agent appropriately. Therefore, the speed of the drive motor is adjusted corresponding to the process conditions. One special feature of this controller is that it knows the pump's characteristic curve. This enables the system to be adjusted significantly faster compared with a conventional PID controller.

The system offers big flexibility. Even conversion from butane to CO2 is no problem: Another suction side heat exchanger is integrated into the pipeline and a cooling jacket installed on each pump head to reduce the temperature of the liquid gas before it enters the pump.

Moreover LEWA also offers a solution for metering melted additives: electrically or steam heated systems are designed for a process temperature range of up to 130 °C.

The systems will be presented at the K 2013 trade show in Hall 7a, booth B35-4, where our experts will be available for questions and discussions.