In the drive to maximize productivity, highly advanced technologies often garner the attention. One firm, Plastics Engineering Co., a producer of phenolic resins and compounds based in Sheboygan, WI, however, boosted its efficiency in delivering dry bulk materials to its packaging lines by a humbler means: a materials-handling system equipped with an innovative multiport diverter valve formed from several “sliding-gate” diverter valves.
Plastics Engineering started out as a molder 75 years ago, but today primarily produces phenolic materials. It does maintain a molding division to serve some long-time local customers.
Last spring, the firm commissioned a new materials-handling system to take freshly- ground virgin phenolic resin from multiple grinding stations to packaging lines for shipment. Each of the grinding stations fills a blender in multiple-thousand-pound batches. (Plastics Engineering declined to reveal process figures.) Previously, each grinder processed a batch of resin in about one to two hours and then had to be shut down while operators manually moved the ground resin to the packaging line, a process which took about another hour.
In contrast, its materials-handling system, assembled from components from various suppliers, including several sliding-gate diverter valves by Salina Vortex Corp., in Salina, KS, can select which packaging line is ready and deliver material to it in about 20 minutes, explains Tom Badura, Plastics Engineering’s electronics project engineer. “There is still a period of shutdown,” says Badura, but the company is approaching continuous operation.
Most diverter valves direct the flow of material at the Y-shaped intersection of pipes, blocking one pipe with a plug, gate, or blade while allowing materials to flow through another. The sliding gate diverter valve Plastics Engineering uses, on the other hand, passes a gate through a number of pipes arranged in parallel. Since the gate has only one hole, it blocks all pipes but one. This design makes it easy for material from one location to be directed to up to four locations. Since the destination orifices are never fully closed off during shifts on the sliding-blade design, several sliding-gate diverter valves can be stacked to form a multiport diverter valve.
“The sliding-blade design makes the multiport diverter valve possible,” notes Kevin Peterson, Salina Vortex’s marketing manager. With a sliding-gate diverter, “you can shift on the fly.” Peterson notes that with other valve designs, the blower often must be shut down to change materials.
“What this type of valve allows (Plastics Engineering) to do is go from multiple sources to multiple destinations without having to use a hose manifold station,” says Peterson. He says hose-manifold stations are cumbersome, potentially dangerous, and labor intensive, since the materials line must be shut down for all the hoses to be manually reconnected when the source and destination are changed.
Peterson says Salina’s sliding gate/multiport diverter valves are typically used to direct resins and powders. “The most complex (application) we've done,” he says, “is five sources to 19 destinations, and (the manufacturer) wanted to run four lines simultaneously.”
Badura says Plastics Engineering is considering adding blenders so the grinder can switch and continue operating while the full blender is unloading. It is considering installing a similar system for its raw-ingredient materials, which it stores in large silos.
But Badura admits a system is most beneficial when material is switched often. “There's much more switching involved in the packaging line,” Badura explains. “Whereas with the raw ingredients, there is much less switching involved.” Packaging requires switching several times an hour, while the raw materials require switching only once or twice a day.
“The productivity increase is the prime reason you install this type of system,” says Badura. Still, not only can the automated system better handle an increase in (orders) and free up operators, there's also “verification that (resin) is going to the right place.”
