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WeighPack Systems develops controlled atmosphere packaging in a stand-up bag

July 31, 2009  By Fruit & Vegetable

July 31, 2009 – Controlled Atmosphere [CAP] involves the removal of air from within the package that contains the product.

July 31, 2009 – Controlled Atmosphere [CAP] involves the removal of air from within the package that contains the product. The intent is once the bag has been filled with product; replace the air within the package with an inert air [often nitrogen and CO2] that suspends product deterioration in a safe and natural way before sealing the bag.
The key to successful product freshness is maintaining the residual oxygen level of atmosphere in the bag between 0 and 2 percent depending on the type of product.

Certain products like nuts, coffee, spices, snacks and chocolates tend to lose flavor, texture and color over time. By adding CAP to the product package, the product’s shelf life can be extended 10 fold. For example, nuts packaged in a CAP pouch will be as flavorful in 9 months as the day they were packed.


Given that oxygen is the catalyst of this deterioration, gas flushing alone is not the solution since this process is not consistent. Residual amounts of oxygen will vary bag to bag therefore the most dependable solution is to vacuum the contents of the bag and gas flush prior to sealing.

The main benefit of using CAP during the packaging process is a significant reduction in product returns from the retailer due to customer dissatisfaction.  

WeighPack Systems began studying a method of adding CAP to their SwiftyTM line of horizontal bagger. Typically Vacuum/Gas flush is a slow process and usually can only cycles from ten to twelve bags per minute. This tends to be too slow for most packagers.  WeighPack’s objective was to achieve between twenty-five to thirty bags per minute on a real CAP package.

After months of design, prototyping and trials, the SwiftyTM Bagger 3600 and 1200 can be fitted with a CAP station that assures a controlled atmosphere.  A unique feature of this station is that it can either gas flush or vacuum seal the bag or do both.

The new CAP assembly includes a 10 CFM vacuum pump with a filtering device to capture any floating product and a single or dual snorkel which plunges into bag and activates the process (gas flush, vacuum or both).  Once the snorkel retracts, the bag is stretched to avoid any loss of atmosphere and is quickly sealed. The travelling rail mechanism puts tension on the bag, moving synchronously with the functioning stations.

Test results show that oxygen residuals are consistently maintained at less than 2%. This technology is best suited for products with an approximate shelf turnover of twelve or less. The prolonged freshness of the product removes any concern over sale-ability and freshness.

The SwiftyTM bagger can handle pouches, stand-up and flat bottom bag types.  Sizes can range up to 12 inches wide by 18 inches long. Bag features include; zippers, carry handles and gussets.  

The Allen Bradley PLC and Touch Screen make the Swifty easy to use and service.  Product set-up is now a breeze due to the encoder driven CAM Shaft. The straight flow thru design of the Swifty allows for an easy to access and easy to service machine. Production flow is improved due to the linear direction as compared to rotary type baggers.

WeighPack offers a variety of filling equipment from augers, scales, piston fillers and counters that can be integrated with the Swifty to form a complete automated packaging system.

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