Canadian Packaging

Pneumatic Conveying Systems

By Lisa Zocco    

General VAC-U-MAX

  1. The first application is a fairly simple system used to package 1,750 pounds of coffee an hour from floor-mounted silos to packaging machines. The pick-up point for the coffee is the floor-mounted silo. Convey tubes connect silos to vacuum receivers mounted on packaging feed hoppers. The vacuum producer in this system generates negative pressure, sucking the material from the silo through 10 meters of vertical convey tubes to vacuum receivers. In this case, level switches control the operation of the four vacuum receivers by signaling for more coffee when the level drops below an established setting. When the coffee in the hopper reaches the high set point, the level control stops the vacuum receivers. The coffee then flows down to the vertical form-fill-seal packaging machines. Because the product in the vacuum line does not come in contact with air, it does not affect the quality of the coffee.
  2. The next conveying solution, seemingly more complicated than the coffee solution, uses high speed conveying and dispensing for a blended self-lathering facial product. Volumetric auger fillers dispense the powder into two layers of non-woven material that are ultrasonically sealed as the powder is dispensed. The powder’s self-lathering properties presented the potential of being critically affected in any type of conveying method. If the powder particles became too small, the facial product self-lathered too fast; and, if the particles became too large, the self-lathering process took too long. In addition, a cha
    nge in the density, component blend, and texture would produce inconsistent fill rates or volumes—both unacceptable for quality control. Testing in Vac-U-Max’s large-scale testing facilities confirmed material flowability and proper convey rate for the product. The pick-up point best suited for this application includes two low-profile drum dump stations for easy loading, powered by a positive displacement vacuum producer that pulls the powder through convey line piping to the receivers. For this system vacuum receivers deliver product into three volumetric auger fillers, supplied by an outside company. A level control automatically delivers powder to the auger fillers at pre-determined volumes .Since powder can change density in the auger filler head leading to improper fills, keeping the head full is critical. For proper powder density in the auger filler heads, and more accurate fills, the conveying expert mounted customized multi-filters to the powder receivers and designed the vacuum conveying system to convey material faster than the packaging machine was dispensing product. Vac-U-Max also applied a high polish finish to the systems interior and exterior to reduce powder sticking inside the system and make the exterior easier to clean. On installation, the conveying expert worked with the facial product manufacturer to adapt the system to their needs. To better accommodate a vertical receiver adjustment mechanism that the facial product manufacturer designed, convey piping was mounted on machinery rather than hanging it from the ceiling or supporting it from the floor. The result was a modular system easy to install or relocate, which took significantly less production floor space than typical material convey systems.
  3. Often packagers must focus equally on plant efficiency, product quality and safety, as was the case in this last conveying solution where a marshmallow producer desired to reduce downtime, and minimize product loss caused by bucket elevators as well as provide a higher level of safety for nearby workers from loose starch in the air. This particular application required extensive testing to ensure mandatory product quality, feed rates, and other variables. After this testing VAC-U-MAX designed two pneumatic conveyor systems that deliver finished marshmallows from processing to six packaging machines. Again, systems were built using five standard components, however, the use of additional components customized the systems to meet the manufacturer’s needs, such as USFDA (U.S. Food and Drug Administration), USDA(U.S. Department of Agriculture)-approved hoses, filter separators that capture and reclaim excess starch from the system, explosion vents, and intuitive controls that enhance flexibility.

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