Mixing: Multi-Shaft Mixer Can Be Customized
Elaborate automation and safety functions added to triple-shaft mixer.
Charles Ross & Son Co., Hauppauge, N.Y., recently designed a custom 150-gal Triple Shaft Mixer (its VersaMix Model VMC-150) with elaborate automation and safety functions. Notable among the special added features are six pneumatic clamps rated for 4000 lb each for remote locking of the mix vessel to the mixer cover designed for 29.5-in. Hg vacuum and 5 psi internal pressure. The clamps likewise function as redundant limit switches, allowing for operation only when secured. The VMC-150 also includes automated valves for powder feed and CIP liquids, RTD multi-point temperature sensor, built-in vacuum pump assembly, load cell system and centralized HMI.
The three independently-driven agitators of ROSS Triple Shaft Mixers include a high-speed saw-tooth dispersing blade for quick product wet out, a three-wing anchor for efficient transport of viscous product throughout the mixing zone, as well as a third shaft, frequently a high shear rotor/stator homogenizer for emulsification. The pictured VMC-150 instead features a helical auger screw for submerging floating agglomerates. When reversed, the auger screw surfaces air pockets resulting in decreased batch cycle time. The sides and bottom of the mixing vessel are jacketed and insulated for operation up to 100 psig at 250 F.
Improved clarity and cost competitiveness, added to its inherent heat resistance, are reviving OPP’s prospects in hot-fill barrier containers. But hot-fill PET containers are raising the bar with higher productivity and ‘panel-less’ bottle designs.
Plastics are going “green,” but they will need some help to get there. Biodegradable polymers derived from renewable resources are attracting lots of interest and publicity, but that enthusiasm is counterbalanced by persistent questions of availability, cost, performance, and processability. All these issues are inter-related: Increasing demand will lead to more capacity, which will presumably lead to lower prices. But the foundation is market demand, which ultimately depends on whether biopolymers will have the performance properties and processability to compete with existing non-renewable plastics.
Over the past several years, significant innovations have occurred in the area of polypropylene nucleation.