High-Pressure Mixhead Upgraded for Rigid Foam

A new mixing head is said to be specially designed to enhance reliability in processing rigid PUR foams.

A new mixing head is said to be specially designed to enhance reliability in processing rigid PUR foams. Model ULP-2K VV G from Krauss-Maffei Corp., Florence, Ky., has a cleaning plunger with reduced metal-to-metal friction and a more powerful hydraulic drive to combat the material’s adhesive tendency during processing. The new design applies up to 30% more force on the plunger at the same hydraulic pressure. Also, a bell-jar installed between the cleaning plunger and hydraulic drive is said to prevent resin from being carried over into the hydraulic system. When cyclopentane is used as the blowing agent, the mold cavity is typically flooded with nitrogen before pouring to eliminate ignitable gases. This processing step has now been resolved with a module that can be mounted directly on the mixhead. Nitrogen is introduced through the discharge tube. Also, the cylindrical sections of this mixhead are made of high-strength aluminum, which cuts weight 25% so that it can be handled by smaller robots or manipulators.