Food Engineering

Weigh belt feeders improve ingredient weighing accuracy

February 1, 2009
Smart weigh belt feeders from K-Tron helped Kar Nuts get its more than 30 blends of salted nuts and trail mix products on spec with 0.5% accuracy. Source: K-Tron.

Kar Nuts Products Company, located in Madison Heights, MI, produces salted nuts, snack food and trail mix blends in flexible 10-16 oz. packages. When growth and expansion caused the company to move to a new facility, the design objective was to produce a state-of-the-art operation with a focus on increased efficiency and product quality. As a result, a completely automated roasting, metering, blending, conveying and packaging process was installed.

Every product has a different combination of ingredients, each with its own bulk densities and material handling characteristics, which presented a challenge to Kar Nuts when selecting a metering and feeding device. Due to the wide variety of feed rates, as well as the fragile and costly nature of products such as coated chocolate, dried fruits and roasted nuts, it was imperative for the feed device to be versatile, gentle and highly accurate.

Prior to the expansion, the production process was mostly manual. Individual ingredients were weighed in buckets/scales and brought to mixing trays. This process was time- and labor-consuming and often produced unwanted blend variations. According to Matt Spence, Kar Nuts production manager, “Our previous methods would produce 8-10% accuracy and material variances.”

Kar Nuts contacted Joe Durlach of Hi Pro Equipment to evaluate the problem. He suggested trying K-Tron’s Model SWB300 smart weigh belt feeder (WBF).

The new process includes two separate roasting lines, producing up to 14,000 lb./hour of product. After roasting, the nuts exit to one of three process-feeder lines. One of these lines, dedicated to the production of the four-component Sweet ‘N Salty blend, consists of four large Gaylord hoppers feeding directly to the intelligent WBF. The additional two lines have similar set-ups, but include five individual WBFs and two additional feeders that can swing into position on either line, allowing production of a seven-ingredient blend at a total capacity of 14,000-18,000 lb./hour for each line.

The WBF has a stainless steel enclosure with a removable conveyor assembly, allowing access for maintenance, cleaning and belt removal. The WBF’s weighing technology has a resolution of 1:4,000,000 in 80ms, as well as built-in immunity to plant vibration.

Each individual ingredient is discharged from the weigh belt in accordance with Kar Nuts’ preprogrammed recipe. All recipes are stored in K-Tron’s Smart Commander PC-based visualization package. The SCADA-based control system and HMI show the exact line capacity and individual ingredient settings, as well as the overall recipe of the blend.

The automation of the entire process has resulted in a significant reduction in labor and ingredient costs, as well as a marked increase in product quality.

“Our primary product is Sweet ‘N Salty,” says Spence. “With the use of the smart WBFs, after feeding through 130,000 lbs. of product, we are achieving 0.5% accuracy on all four ingredients. Such a significant improvement in accuracy also results in a significant ingredient cost savings, as the individual components of our blends can be very costly.”

In addition, Spence states, “We have seen a significant increase in the overall product quality using the weigh belt feeders. Our blends are much more consistent, resulting in a better product for the customer.” v

For more information: Sharon Nowak, 856-589-0500, snowak@ktron.com