The ‘Drying Genie’ marries drying technology and input moisture measurement with a goal to putting an end to drying based on time.
Novatec is moving to redefine resin drying with new, economically priced technology that detects moisture levels in the material before it hits the dryer and then adjusts the drying parameters accordingly. Called the Drying Genie, Novatec will debut the system during the PTXPO 2023 show, March 28-30 in Rosemont, Ill.
The Drying Genie consists of a sensor that’s installed near the bottom of the suction probe or lance that’s typically used by molders to pull resin from gaylords to the dryer to prepare the material for processing. This sensor relies on capacitance or near-infrared technology to measure moisture in the resin on a parts/million (ppm) basis long before it’s drawn into the dryer.
The sensor constantly communicates with the dryer controller and automatically adjusts drying residence time, airflow and temperature to account for the moisture reading. The system is retrofittable to Novatec dryers purchased since 2016. At its laboratory in Baltimore, Novatec has run the Drying Genie on various nylons, PC, PC/ABC, acrylic and TPUs.
As Novatec explains, the patent-pending sensor apparatus also includes accelerometers, pressure sensors, temperature/humidity sensors and a gyroscope to assist in reliable inline moisture measurements. Since moisture presents a very high dielectric constant compared with the low dielectric constant of plastics, the presence of moisture can very reliably be detected, and then instructions are coordinated with the connected dryer to change drying parameters and residence time according to the moisture levels — by the time the material reaches the drying hopper.
“We’re changing the paradigm of resin drying and at the same time challenging some long-held beliefs,” notes Novatec CEO Conrad Bessemer. “The first is drying to the resin supplier’s recommendations that appear on the data sheet. These recommendations are usually very wide: 2-4 hr or 4-6 hr. That’s because by the time the resin reaches the processor, the moisture levels in it may have changed dramatically from when it was shipped and is highly dependent on seasonality.”
“Most processors think drying performance is all about dewpoint. That’s a fallacy.”
Mark Haynie, Novatec’s drying product manager, concurs: “Most drying times from resin data sheets include significant safety factors, which result in overdrying, wasted time and wasted power. In most cases, the starting moisture point is unknown. Even two gaylords received the same day can have dramatically different starting moisture points. To that point, we recently received two gaylords of nylon 66 from the same supplier on the same day. One came in at nearly 3950 ppm, the other at 1750 ppm. But the supplier’s recommendation for drying time and temperature were the same.”