One size never fits all; in food and beverage production, one size often doesn’t fit more than one. Minor tweaks or major customization is more the rule than the exception.
That’s true not only of complex machines but also of seemingly basic conveying equipment. Even when a project entails straightforward horizontal movement of finished goods or raw materials, production managers must consider a variety of factors before choosing the most appropriate belting and conveying option.
Mrs. Miller’s Homemade Noodles Ltd. (www.mmhn.com) went through the decision process twice in recent years. Based in northeast Fredericksburg, Ohio, the heart of the state’s Amish country, the family-owned firm is riding growing demand for preservative-free foods. Beginning in 1975 as a home-kitchen operation, the firm moved into its first production plant in 1990, later expanding it in 2013 and adding a line. In between, Mrs. Miller’s transitioned from manual processes to machine production.
The first pneumatic conveyor for flour relieved workers of the backbreaking task of emptying 50-lb. bags into a feeder tank. The conveyor resolved some issues but created others. The forklift that brought the one-ton sacks to the holding tank had to remain in place until the sacks were empty, rendering the truck unavailable for other tasks.
“The conveying line periodically plugged up, and we’d have to shut down production to unplug it,” recalls Brian Miller, son of founders Esther and Leon Miller. “The gear boxes for the two augers at the bottom of the holding tank would burn out” due to the torque needed to feed flour through the line. Up to 4 percent of each sack’s contents stuck to the inside walls and was wasted, and flour that accumulated behind the holding tank couldn’t be accessed, creating a sanitation issue.
Before completing his medical training and establishing a practice — he was known as the Noodle Doc at Mrs. Miller’s — Brian Miller oversaw a re-do of the bulk conveying system. A local manufacturer’s rep referred him to Belleville, N.J.-based Vac-U-Max (www.vac-u-max.com). A new bulk bag discharge system with a smaller footprint that facilitates clean-up utilizes a bag frame to support flour totes. Lift-truck operators connect bags to the frame, then lift the frame into position above a 7.8-cu.-ft. feed bin. The truck is then free for other tasks. When it’s time to swap out the bulk bag, there is enough flour in the bin to ensure continuous production during changeovers.
A venturi design accelerates the force of compressed air to generate conveying vacuum, a simple and cost-effective solution for moderate-volume processors, explains Mitch Katz, vice president of Vac-U-Max. Fewer moving parts keep maintenance and downtime low, but the biggest improvement is flour movement through the dilute-phase system.
An 8-ft. semi-flexible food-grade hose connects to a 25-ft.-long stainless steel pipe to deliver flour to a high-speed pre-mixer, where other dry ingredients are combined. Nonlinear material movement is a Vac-U-Max distinction, says Katz, and plugged lines no longer are an issue for Mrs. Miller’s.
Materials of use
The industry’s need for multiple conveying options to address the challenges of a specific plant is reflected in new solutions from vendors. A case in point is the new metal mesh belting from Dynamic Conveyor Corp. (www.dynamicconveyor.com), a Muskegon, Mich., supplier that introduced its Dynaclean line for food and beverage processors five years ago.
Plastic-link belting, then solid thermoplastic were the early options from Dynamic. Tool-free assembly and sanitary design were the conveyors’ selling points. “If we’re going to go into the food market, we want to be different and very efficient,” President Jill Batka remembers of the original design. Easy disassembly meant shorter cleaning cycles and reduced water use, but corrosion-resistance and the hygienic advantages of plastic over metal also were distinctions.
At the urging of a client, the firm earlier this year added a plastic belt that can withstand temperatures as low as -50°F. (The solid belts function in the 20-100° range, the link belts at 34-200°.) More recently, Dynamic added wire metal to the mix. The beta application involved salmon patties sprayed with water from the top and bottom before entering a freezer.
“We can do a much tighter transfer with metal than with plastic,” says Batka, “and metal has more open area to allow drainage when liquid or ingredients are sprayed from above.” The ability to function inside freezers was the driver behind the line extension, however.
Eliminating nooks and crevices where food waste can accumulate and making sanitation easier have been design priorities for a decade. Improvement is continuous and usually incremental, but engineers at Key Technology (www.key.net), Walla Walla, Wash., believe they have a breakthrough with the new monobeam design for their line of vibratory conveyors.
Instead of a box-shaped base, Key’s Iso-Flo monobeam is narrower than the bed it supports. Spring arms are tucked under the bed, reducing the number of surfaces that need to be cleaned. The base is stainless steel, another nod to sanitary design, but feedback from beta-site users suggests its narrowness is the bigger benefit.
“The feedback from food manufacturers is that it fits more closely in catwalks and nests closer to the machine,” reports Jim Ruff, head of conveying engineering. Less stretching during cleaning is a plus for sanitation workers.
Shrinking the conveyor’s footprint posed a challenge in maintaining side-to-side stability when the conveyor is running. Asked how the issue was resolved, Ruff would only say “we applied some unique techniques,” adding that deflection from the springs is the only motion transmitted through the base to the floor.
“This was many years under development,” he adds. “We refined the design significantly in the last two years. Aggressive trials began last year. It’s a configuration that customers became excited about.”
It didn’t take quite that long to design the staggered sidewall belt used with Dorner Manufacturing Inc.’s first bucket conveyor, though more than a year was invested in the effort, according to Mike Hosch, vice president-industrial products business unit at the Hartland, Wis., firm (www.dorner.com). Trapezoidal pieces of urethane are RF welded in a scalloped pattern to form the sidewall. Only a fifth of the side length is used for the weld.
Continuous-weld corrugated sidewalls are prone to splitting. The Dorner design overcomes that shortcoming, says Hosch, and more importantly the scallops make it easier to flush out trapped food waste. The proprietary belts are manufactured exclusively for Dorner by Gates Mectrol Inc.
Dorner launched its first sanitary-design conveyors for food in 2004, focusing on V-frame units until now. Vertical lengths of the new AquaPruf VBT range from 10-20 feet. The conveyor is targeted at fruit & vegetable processors, candy manufacturers, snack food companies and rice and grain processors, according to Hosch. “All of our targets have seen the benefits.”
Solid urethane belts enjoy some advantages over metal in terms of food-contact contamination, but multi-plied urethane belts require a layer of fabric if they are to run in the 600-700 feet per minute range, according to Andy Balog, regional sales manager at Sparks Belting Co. Inc. (www.sparksbelting.com), Grand Rapids, Mich. To prevent microbes from migrating from the belt edge to the fabric, Sparks is introducing capped edges that are thermo-welded to the belt to provide an impenetrable barrier.
Capped edges also are an added precaution for urethane belts used in meat and poultry applications. Those belts run much slower, but the edges also are subject to fraying.
Capped edges require a V-guide along the center line of the belt to ensure proper tracking and prevent excessive contact with the conveyor frame. Sparks thermo welds urethane guides with very tight tolerances to work with Rheon conveyors, which have shallow belt grooves, Balog explains.
Sanitary design must be balanced with the need for worker safety, points out Jim Paulsen, sales account manager at Multi-Conveyor LLC (www.multi-conveyor.com), Winneconne, Wis. “Often the sanitary design and safety requirements seem incompatible,” he says, “and it is left to the conveyor manufacturer to comply with both groups’ specifications.”
Like many conveyor fabricators, Multi-Conveyer works with belt makers to come up with equipment to meet the specific cleaning regimens and considerations of individual food companies. Among those suppliers is Regal-Beloit Americas, which supplies plastic conveyor chains, modular plastic belts and other components. The objective is to lower total cleaning and operating costs while also delivering a hygienic solution for product movement.
Not all conveyors in food plants need to meet strict sanitary standards, of course. Lower standards apply in packaging departments and other areas. Nonetheless, proper housekeeping is central to current Good Manufacturing Practices, and that puts a premium on semi-customized solutions for each manufacturer’s operating environment.