Plastics Technology

FEB 2018

Plastics Technology - Dedicated to improving Plastics Processing.

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Which ElboW ProblEm Do You NEED to SolvE? ProblEm cAuSE SolutioN Formation of streamers, angel hair and snake skins when conveying plastic pellets Plastic pellets skidding and/or bouncing against the outside radius of sweep elbows create friction and heat, melting pellet surfaces. Smart Elbow ® replacements from hammertek eliminate these problems by eliminating impact Unlike conventional "impact" elbows and "plugged-tee" elbows that rely on material impact to change direction, HammerTek's Smart Elbow ® design features a spherical chamber that protrudes partially beyond the desired 90º or 45º pathway, which causes a ball of pellets suspended in air to rotate, gently deflecting incoming pellets around the bend. No impact means no wear and no fines and no streamers, angel hair or snake skins. Wear and failure when conveying glass-filled, mineral-filled or other abrasive pellets Abrasive pellets hit the outside radius of conventional impact elbows at high speed, continually wearing through the elbow wall. FF-0975 Free, No-risk trial offer See how Smart Elbow® deflection elbows eliminate conventional and plugged-tee impact elbow problems—at no cost or obligation. 1-610-814-2273 sales@hammertek.com www.hammertek.com 45° and 90° elbows available in diameters ranging from 1.25 to 18 inch In cases where operators change a gaylord or resin source—and the resin tempera- ture or moisture is different from the previous lot—the dryer control automatically adjusts to maintain the temperature profile. Competing temperature-setback features require operators to determine the temperature at which the drying temperature should be lowered and to what temperature it should be reduced. OverDry Protection, on the other hand, is an automated control process that takes the guesswork and human inter- vention out of the process. OverDry Protection will be standard on Novatec's NovaWheel portable dryers; Moisture Manager will be available as an option. NITROGEN DRYING At NPE 2018, Novatec will also take the wraps off a new Nitrogen NovaDrier. As with the Moisture Manager and OverDry Protection system, this technology was also developed in response to increased use of polymers with unique properties that can be diminished if not handled properly during the drying process. The dryer introduces an inert gas or nitrogen to inhibit the oxidative degradation of polymers. Resins that tend to degrade with prolonged exposure to heat in the presence of oxygen include nylons, PBT, PLA, and TPUs. A loss in properties due to oxidation occurs more readily in the presence of the heat used in drying. Each polymer has different limits on tempera- ture and the amount of degra- dation that occurs with exposure to heat and oxygen during drying. Typically, the drying tempera- ture can be 10-50° F higher with a nitrogen source in lieu of air, allowing for shorter drying times. These shortened exposures lead to better polymer performance in terms of strength, ductility, color/clarity, viscosity, chemical resistance, stiffness, and stability. Using nitrogen in dryers is not altogether new. This dryer is unique, however, in that it requires no handling of cryogenic nitrogen or bottles. There isn't any need to have both the handling and risk of using bottled nitrogen. This dryer uses standard plant compressed air as the feedstock, from which it extracts the nitrogen for drying, so only air is released from the dryer unit (in two streams, one oxygen- rich, and one nitrogen-rich). This approach eliminates the hazards involved with venting of nitrogen into a closed area. It can be used anywhere without special procedures or handling, Novatec says. Novatec's nitrogen drying system here is equipped with an integral hopper. 22 FEBRUARY 2018 Plastics Technology PTonline.com D R Y I N G Close -Up On Technolog y

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