Ingredient Screening Upgrade Boosts Pet Food
Production, Cuts Labor, Improves Quality


 
Mobile 30 in. (762 mm) diameter vibratory bag dump screener sifts dry ingredients prior to mixing them with meat protein. The waist-high unit minimizes physical effort in bag dumping, and includes a built-in dust collector.
 


 
Screened dry ingredients are conveyed into a mobile bin that is wheeled to the processing side of the plant.
 


 
An operator weighs the amount of ingredient to be screened.
 


 
Mobile bins of screened material are wheeled to the processing side of the plant.



QUAKERTOWN, PA — Freshpet, a processor of high-end refrigerated dog food, replaced manual screening equipment it had designed, built and installed, to clear a production bottleneck, reduce heavy lifting and improve product quality.

Established in 2005 by dog lovers John Phelps and Scott Morris, Freshpet produces products under two brand names for nationwide distribution through approximately 3,000 retailers. "Dog Rolls" are available in one-pound through six-pound chubs and "Fresh Bites" are meatballs for dogs. All of the products, which are marketed in supermarkets under the "Freshpet Select" brand and in specialty pet retailers under the "Deli Fresh" name, are made from fresh ingredients, including chicken, carrots, peas and rice, and contain no byproducts, fillers or preservatives.

 DIY screening

Freshpet sifts and screens dry ingredients to maintain particle size uniformity, remove clumps and incidental foreign material prior to mixing the ingredients with meat protein. The company's maintenance staff had designed and built a 20 in. x 20 in. (508 x 508 mm) sifting screen that could handle about 10 pounds (4.5 kg) of ingredients at a time, and an employee had to manually push the ingredients through the screen with a scraper. "Our guys went to a local box hardware store for the materials. It was a real do-it-yourself affair."

"It was a sturdy little screen and kind of ingenious in its way," explains Michael Hieger, Freshpet's general manager, "but we were having issues with small clumps in our dry ingredients. It would take us upwards of one hour to manually sift enough dry ingredients for one batch."

The company decided to upgrade the screening process for this and several other reasons: 1) It was forced to hire temporary help for screening when an employee could not be spared from another processing line, 2) Dry ingredients are supplied in 50 lb (23 kg) bags which are too heavy for some workers to lift and pour onto the screen, and 3) Ingredient uniformity. The manual process "did not produce the kind of uniformity we wanted in our dry ingredients," explained Hieger. "The quality wasn't there."

From hours to minutes

Freshpet purchased a mobile, circular vibratory, bag dump screener from Kason Corp. that discharges into the feed hopper of a flexible screw conveyor.

The screener is a Vibroscreen® Flo Thru (low profile) model with a single-deck 30 in. (762 mm) diameter screen and built-in dust collector.

A worker now dumps a full bag of dry ingredients onto the screen that, at half the height of Freshpet's homemade screener, reduces physical effort, while the dust-containment system improves safety and plant hygiene. The screener employs two imbalanced-weight gyratory motors, mounted externally on opposite sides of the screener, to impart multi-plane inertial vibration that maximizes the rate at which particles pass through or across the screen surface. Material clumps and foreign material discharge through an "overs" discharge spout at the screen's periphery, while on-size particles (=5.66 mm) gravity discharge at a rate of 50 lb/min (23 kg/min) into a flexible screw conveyor that is 6 in. (152.4 mm) in diameter, 6 ft (1.8 m) long and inclined at 45-degrees. Screened material is conveyed into mobile bins that are wheeled to the "processing" side of the plant for blending with proteins and cooking.

Mobility was important because the screening operation runs on an as-need basis, and Freshpet wanted the option to use the space for additional purposes, and to empty the area for washdowns between shifts.

"What used to take us an hour now takes 10-15 minutes, and one person can easily lift 50 lb (23 kg) bags to the height of the low profile screener," explains Hieger, adding, "The efficiency gained by the system is such that Freshpet's production would have to increase a large amount before the screening operation once again bottlenecked production."
 
 Robertson Equipment Company 10950 Pearl rd., Suite A1 Strongsville, Ohio 44136 Copyright 2010 All Rights Reserved