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Circular Separator Raises Productivity In Producing Sweetened, Dried Cranberries

Decas Cranberry Products, Inc., Carver, MA, producer of sweetened-dried cranberries, improved throughput and lowered product loss after installing a 4' diameter circular vibratory screener for separating undersize cranberry pieces from a cranberry-syrup slurry. Additionally, Decas processes 10,000 gallons before changing downstream filters one-fifth as often, while saving more than $20,000 per year in labor and filter bag costs.

Before installing the screener, the cranberry-syrup mixture flowed directly into four 300-micron canister filters. Decas could only process 1000-2000 gallons before the filters would clog with undersize cranberry pieces of skin, pectin and fruit particles. "Depending on the quality of the fruit and the slicing job, the filtration system sometimes clogged quite rapidly," says Andre LaPerriere, Decas director of manufacturing. Decas had to change filters five times as often as today.

Now, the undersized particles (as small as 500 micron) are taken out before the filters by two Kason Corp. VIBROSCREEN® circular vibratory separators. Downtime is diminished as well as product loss when changing filter bags. Decas saves in labor costs from fewer changeouts, and saves in costs of fewer filter bags.


How Sweetened, Dried Cranberries Are Produced

Decas Cranberry Products is one of leading purveyors of cranberries worldwide. The company produces sweetened, dried cranberry slices for cereals, trail mixes, bagels, turkey stuffing and other food and bakery items. In producing the dry raisin-size 3/8" pieces, Decas sweetens the naturally tart cranberries with cranberry syrup to 55-brix sugar content in an infusion tank. The heavy, thick syrup mixed with cranberry slices flows from the tank into the circular vibratory separators, which separate and discard the undersized pieces before the syrup is filtered for reuse.

Decas recently added a second Kason circular screener, which separates the largest pieces, increasing flow sixfold to 18,000 pounds per hour.

As the mixture of syrup and cranberry slices flows through the first VIBROSCREEN, the unit's top #4 screen separates pieces down to 3/8". They are discharged through a side-mounted spout to a conveyor and transported to a dryer that produces finished product. The undersize pieces are separated by the screener's middle deck with a 500-micron (38-mesh) screen. These particles are discharged through a second side-mounted spout into a container and discarded. The syrup exits the VIBROSCREEN from the bottom deck discharge, then flows through the filters, and is pumped to a storage tank to be re-standardized and reused. The filters catch the smallest particles up to 300 micron.


How Circular Vibratory Screener Works

The 4'diameter VIBROSCREEN circular vibratory screener is equipped with one imbalanced-weight gyratory motor positioned beneath the screening chamber. The motor imparts multi-plane inertial vibration to the spring-mounted screening chamber, causing oversize particles to vibrate across the screen surface in controlled pathways to the screen periphery where they are discharged. Undersized particles and liquid pass rapidly through the screen. Each screen is equipped with a feed tray to redirect the undersize particles to the center of the screen beneath. This greatly increases screening efficiency by forcing material to pass over a maximum amount of screen surface.

The circular screener provided a quick solution for this startup plant. LaPerriere ordered the Kason VIBROSCREEN, being familiar with the concept from trade magazines and observing it in other processes. "I knew it could handle our tough, dense, sticky product." He says installation of the screener went smoothly and easily.

Before building this plant, Decas at another location passed the cranberry-syrup slurry through a perforated conveyor. The large pieces were supposed to travel along the conveyor, while the juice that fell through the perforations was supposed to take the small particulates to filters for removal. "It didn't do a good job at all," says LaPerriere.

As the nation's appetite for cranberries increases, Decas has found a way to produce top quality sweetened, dried cranberries at a productive rate. This advance supports Decas' quality claim that its product is free of extraneous plant matter and foreign matter. The productivity increase helps consumers enjoy cranberry-containing foods at reasonable prices.