Preventing Cross Contamination

Since it might spray multiple colors per day, Rapistan must keep stray powder particles from contaminating new colors...

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Rapistan Systems is a world leader in material handling systems and information processing solutions for e-commerce fulfillment, distribution, manufacturing, parcel and freight, postal, air cargo and baggage handling applications. In one of Rapistan's manufacturing facilities they fabricate and assemble conveyor systems and machines that sort mail for the United States Postal Service.

In its 312,000 ft2 facility in Grand Rapids, MI, Rapistan powder coats the manufactured components because the process is more durable and provides a better finish than spray painting. The items are powder coated in a spray booth using a manual spray gun before entering a cure oven. Throughout the operation, the spray gun emits microscopic powder particles into the booth.

During the coating process, the filtration system in the coating facility captures the excess powder in the air, but a vacuum cleaner is needed to collect the overspray that settles on the floor, walls and ceiling. While ordinary commercial vacuum cleaners do an adequate job of collecting powder, they are unable to retain the fine dust.

After recently adding a number of new colors to its process, Rapistan realized it needed a more powerful machine to avoid costly cross contamination. The company called Nilfisk, who had supplied the company with industrial vacuum cleaners before. Because of its increased airflow and greater collection capacity, the CFM 137 was recommended.

Due to static electricity, the powder clings to everything it touches. The rooms where the powder coating is done are constructed entirely of stainless steel, making cleanup especially difficult. Powerful suction is needed to pick up the powder. Scott Uzarski, an industrial engineer at Rapistan, stated, "Usually 110 volt machines aren't powerful enough, but the CFM 137 easily handles the job."

Cleaning is done once a day unless there are color changes. In that case, cleaning is done more than once. Previously, the cleaning process took 25 minutes. Thanks to the new vacuum cleaner, now it only takes half that time. Less time cleaning up means more time can be devoted to the powder coating process, improving the efficiency and productivity of plant operations.

The vacuum cleaner purchased by Rapistan is designed for the safe and effective collection of ultra-fine powders. Bypass motors with their own cooling air source protect against motor burnout and clogging. The CFM 137 is equipped with a three-stage filtration system, with each stage retaining progressively finer particles. After the larger, heavier particles are deposited into the collection container by cyclonic action, the remaining dust and debris is carried by the air stream through the main filter and a HEPA filter, which retains 99.999% of particles down to 0.3 micron. The trolley is equipped with large wheels, bearings and brakes for maneuverability and safety. Accessories include flexible anti-static hoses, lightweight wands for overhead cleaning and fllor tools ideal for any type of surface.

Mr. Uzarski said, "We particularly like the external filter shaking mechanism. It keeps the filter free of clogging dust and maintains the vacuum's maximum suction power. We can clean the filter without disassembling the machine."

The vacuum cleaner contains additional features that make it user-friendly, such as a convenient foot lever that lowers the wheeled collection container for easy emptying. Mr. Uzarski thinks this is why the CFM 137 is so popular with Rapistan's employees. "If it's hard to maintain, the guys won't use it," proclaimed Mr. Uzarski.


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