Closed pneumatic conveyor system eliminates dust and downtime

While the screw-type mechanical conveyor has its place in industry, when it comes to handling dry materials that must be kept free of contaminants, and environments where dust-free conditions are important, these conveyors systems are often problematic.

By Plant Engineering Staff September 17, 2003

In addition to dust and contaminant exposure, screw-loading (or, augur) conveyors can induce a “shearing” effect on materials, especially powders, whereby they become partially compacted by the screw apparatus, resulting in materials that lack consistency. Screw conveyance of dry materials can also entail cumbersome labor, with attending safety concerns and product spillage.

In many cases the pneumatic conveyor system, which can be completely enclosed for many applications, is an ideal alternative to many screw conveyor systems. Today’s microprocessor-controlled pneumatic conveyor systems can enable businesses to overcome contamination, dust and shearing problems, and offer sizable productivity gains. Applications for pneumatic conveying systems span the process industries, including nutrition and healthcare products, automotive products, chemicals, packaging – wherever the conveyance of dry materials can benefit throughput, agility, quality, safety and ergonomics.

In the case with Tropical Foods, Company, Inc., Clifton, SC, the main difficulties with its screw conveyor system were dust and problems associated with the motor that drove the conveyor. Also, the screw conveyor system was by no means optimized in terms of throughput; thus, productivity was not as high as it could be.

“Tropical Foods produces Tropiway Plantain and Cocoyam FUFU Flour, a traditional African food that is popular as a staple in the diets of many people around the world,” explains Tropical Foods President Edward Ofori. “From a quality standpoint, it is very important that our products are contaminant free. From a production perspective, it is also important that we produce these products as efficiently as possible in a worker-friendly environment.”

Producing Tropiway specialty flours entails the dumping of approximately 2,500 lbs. of various ingredients, in powder form, from bags into a mixer. After blending, the product is transported to a flour filling station where it is bagged and then put into boxes that go on store shelves.

The process is pretty straightforward,” Ofori explains. “We were using a screw conveyor to transport the materials. However, this method always produced a great deal of dust from the powder ingredients. Plus, the motor driving the screw tended to leak oil after a couple of months of operation. This motor was located above the mixer, so we had to be very wary that the oil did not drop into the flour mixture, causing contamination that would be entirely unacceptable.”

Ofori says that when the screw conveyor motor needed service, it would have to be removed and taken to a shop, which would cause a day or two of downtime. “The alternative was to buy and install a new motor, which we did on several occasions. But there was still a certain amount of downtime involved in replacement – not to mention the expense of motor repair or replacement.”

Tropical Foods first considered changing to a closed pneumatic system when approached by John Reinke of Solid Design Southeast, Charlotte, NC. A supplier to the “process community” in the Carolinas for over 25 years, Solid Design Southeast is a distributor for VAC-U-MAX systems (Belleville, NJ), a major supplier of pneumatic conveyor systems.

After reviewing the Tropical Foods situation, Reinke suggested an automated, closed pneumatic system composed of VAC-U-MAX products, including a bag-dump station, vacuum pickup device, vacuum receiver, and control panel. The turnkey system would be driven by an electric vacuum pump and also include an inline check screen to filter and recover flour powder dust.

Ofori elected to go with the pneumatic system, which promised to eliminate all motor and dust problems, and dramatically improve productivity as well.

Installing the new system was relatively simple. Production was discontinued for about two days while an electrician installed the control panel and some new wiring for the new system. Otherwise, installation of the pneumatic system took one long day, says Ofori. He adds that Reinke assisted with the installation of the VAC-U-MAX equipment, ensuring that the entire system would be ready to operate the next morning.

Ofori says Tropical Foods productivity has increased a whopping 80 percent with the new system. Further, downtime has been nil since the system was installed.

For more information about VAC-U-MAX pneumatic material handling or industrial vacuum cleaning solutions, contact VAC-U-MAX by mail at 37 Rutgers Street, Belleville, NJ 07109; telephone (800) 822-8629 or (973) 759-4600; E-mail: ; or visit the web site: .