Conair’s R-PRO Conveying System Offers Variable-Speed Capability

The patent-pending R-PRO™ dense-phase vacuum-conveying system that Conair introduced at K 2016 is said to help to minimize pellet fracturing, “angel hair” and equipment wear caused by conventional dilute-phase conveying. Conair presented the results of R&D efforts aimed at taking advantage of the fact that the system can be “tuned” to match material speed to application requirements and the characteristics of the material being conveyed.

When the Conair first introduced its R-PRO^® (for Resin-PROtection) conveying system a year ago, the focus was on slow-speed, dense-phase conveying, which eliminates pellet fracturing, dust, “angel hair,” equipment wear and other problems caused by conventional high-speed vacuum conveying. However, the system’s inventor, Doug Brewster, Conair’s conveying product manager, says R-PRO is not only capable of running at low speeds. It also can operate in the more conventional dilute phase, with individual pellets fully suspended in the high-speed air … or at any speed in between.

As material speed increases, Brewster says, there is a gradual transition from dense phase to dilute phase, and “we have found we can control that transition very effectively and run right on the edge in a sort of mixed-pulse phase. We think we can use this for higher-volume unloading where more airflow may be desirable but truly high-speed operation is not necessary or desirable.”

Conair says that response to this innovation has been very positive, especially since conveying throughput and distances are comparable to high-speed systems. In addition, since R-PRO uses standard deep-vacuum pumps, conveying tubes and material receivers, the system costs only a little more than conventional systems and can be easily retrofitted to existing systems.

The variable-speed capabilities of R-PRO now give processors the flexibility to tune the system to their exact needs. For highly abrasive glass- and mineral-filled materials, Brewster added, the slowest material speeds are “absolutely the best.” However, he said, “we are finding that we can run at higher speeds with some materials and still avoid a lot of the usual problems. This can be a big advantage for unloading bulk trucks and railcars where more airflow is helpful.”

He suggests this mid-range speed would be good with materials such as PET and acrylic, which are only mildly abrasive, or with light-bulk-density materials (e.g., 15 lb/cu ft), such as PE sheet flake.

“It’s really easy to raise or lower material speed and airflow,” Brewster said, and the customer can set up and store up to 10 programs per receiver station, and convey different materials at different speeds. www.conairgroup.com