Patent Report: Air-control system boosts recovery

May 15, 2019

A newly patented air-control technology increases recovery of flexible plastics, according to maker MSS Inc., which has installed the system on more than 60 of its Cirrus PlasticMax and Cirrus FiberMax optical sorting systems.

Dubbed PrecisionFlow, the technology involves a metal hood that encompasses at least one conveyor belt and includes air nozzles that produce an airstream to separate and transport materials. It provides greater control over the movement of waste items than existing technologies, said MSS, a Nashville-based maker of recycling systems.

“Because of the optimized shape of the hood, we have much better control of the trajectories inside the PrecisionFlow eject hood,” MSS Sales Director Felix Hottenstein said in a press release about the patent.

According to the patent, PrecisionFlow transfers an airborne stream of ejected material to different conveyors or ejection chutes. It is especially useful in handling lightweight materials, such as film, that tend to be blown around in a stream of air, rather than directed by it.

In the setup designed by MSS, materials, including paper, cardboard, bottles and film, along with other plastic waste, enter the sorting system on a conveyor, which carries them past an optical sensing system. The materials are blasted with a stream of air — either before or immediately following inspection by the sensing system — that separates light objects from heavier objects, such as fibrous materials.

Items such as plastic bags are then directed by air to a secondary stream. This secondary stream passes under the ejection hood, where the materials are again hit with air and directed onto another conveyor. The hood includes lower and upper chambers that can receive separate streams of material. Air travels down and along the hood, hitting the outlet conveyor and forming a vortex that MSS characterizes as important to material- flow control.

“With the organized swirling flow, the ... materials [being carried] can eventually fall out of the swirling flow due to gravity and are not blown back through the chamber inlet by random chaotic turbulent flow,” the patent states. “This swirling flow may be described as an entrapment vortex in which the ... materials are entrapped until they fall out due to the action of gravity.”

The setup allows for “the efficient transfer of lightweight materials,” according to the patent.

MSS’s  Cirrus PlasticMax is designed for recycling containers and accurately identifies and recovers challenging materials, such as black plastics and PETG, while the Cirrus FiberMax is built for paper recycling operations.

Patent 10,131,507; issued Nov. 20