Conveyors move without a hitch
February 12, 2016
by Dan Malovany
Once in a while, a production supervisor will walk into a bakery or snack facility and sense that something is just not right. Maybe it’s intuition, instinct or simply a gut feeling from years of experience on the production floor.
Or it just may be the equipment signaling — maybe even shouting out to operators — that something unfortunate is about to happen unless maintenance takes immediate corrective action to resolve a pending problem.
In the world of conveying, any vibes are usually bad when moving cookies, crackers, pies, dinner rolls or frozen baked goods from the oven via a cooler or through the freezer and into packaging. Only the steady humming sounds of smoothly moving equipment and the seamless visual flow of products into the packaging department provide that inner sense of well-being.
With conveyors, an ounce of prevention often saves a ton of waste. “Vibrations can be caused by several things,” noted Ricky Milner, technical service engineer, Wire Belt of America, Londonderry, NH. “The best way to stop any vibration is to properly maintain the conveyor. If any component is misaligned or not functioning properly, it will result in a vibration as well as belt fatigue and damage to the equipment. There should be a preventative maintenance program in place to identify and eliminate potential problems.”
Even in a bread bakery, vibrations can really shake things up when it comes to ensuring the quality of production. On pan lines, transfers become the critical control points between the proofer and oven prior to baking, according to Allan Rice, conveyor systems product manager, Stewart Systems, Plano, TX.
“Too much vibration of the pan at this stage can cause the proofed dough to lose its rise,” he said. “Transfer points in this phase of the baking process pose a challenge: The chordal action of the modular belt as it rotates about the sprocket teeth will cause the pan to vibrate.”
To solve this problem, Stewart Systems and Baker Thermal Solutions developed an overlap conveyor design that supports the pan before and after the shafts on the connecting conveyors and transfers the pan above the uneven chordal action of the belt as it rotates about the drive sprockets.
IJ White, Farmingdale, NY, tackled the issue with its patented Automatic Belt Tensioning (ABT) system that controls the smooth operation of the belt. “Conveyors can experience belt vibration under two different circumstances: overtension and undertension,” said Peter White, president. “ABT monitors and controls the tension level in our spiral systems, and it can dramatically extend the operating life of conveyor and spiral belts.”
He added that ABT reduces belt wear as well as compensating for the natural stretch and elongation by applying only the necessary weight required to optimize the system’s belt performance. Moreover, reducing belt rod and picket wear means less stretching and a longer belt life. “It keeps belts running smoothly while reducing jerking, vibrating or lifting,” Mr. White said.
When it comes to belting and conveying, belt wave or wander also are common issues. Typically, it takes an eagle’s eye from an experienced technician to set things straight, in more ways than one.
“If we run into an issue, we have a good base to figure out how to correct it and get the belt running right,” said Jonathan Lasecki, chief engineer, Ashworth Bros., Winchester, VA. “We have to go in and walk that fine line to find out if it’s the conveyor or a processing problem and determine the root cause of the issue.”
Every application, he noted, tends to be unique. Sometimes veteran technicians find the root cause goes back to how the conveyor was installed. “Technicians can find ways to set up conveyors to minimize vibration, and a lot of that involves proper set-up,” Mr. Lasecki said. “Are the rollers rolling? Are they perpendicular? Are they level? Are they at the correct spacing? What adjustments need to be made? It’s not always intuitive. In many cases, it involves ‘here’s what I’ve done to make it work in the past’ to solve a problem.”
On high-speed lines, precision baking and conveying collaborate to minimize waste, especially when it comes to cookies, crackers and similar snacks. “Products that are less than an inch in length or diameter can get caught in the gap when transferring from one conveyor to another,” Mr. White said.
For smaller products, bakers and snack manufacturers will usually need tighter transfers as well as better positioning and release,” according to Sebastian Miles, industry segment manager, food, Habasit America, Suwanee, GA. “Initial positioning will be important because the more you interact with the product, the higher the waste and crumbs will be. Release is also key because these smaller items are conveyed individually and not in a container,” he explained. “As a result, the buildup on the belts will both increase your waste and potentially cause problems with positioning.”
It’s not only size that’s an issue, observed Scott Swaltek, vice-president of engineering, Capway Automation, York, PA. “Mini products are usually lighter in weight, which means that smooth control of the conveyor system is important if the products must stay aligned during movement throughout the plant,” he explained. “Stop/start and acceleration/deceleration functions must be controlled via soft-start or variable-frequency drives to help prevent slipping on the belt.”
Slashing waste can come from using more flexible belts that provide tighter, knife-edge transfers and better release so that the product continues on without adhering to the belt. “On plastic modular belting, we have had great success with micropitch [0.3-in pitch] belting, which offers a tight transfer that isn't common for most plastic belts,” Mr. Miles said. “We have expanded on this idea by offering a variety of surfaces on the micropitch line, such as flush-grid design and a flat top with inverted diamond structure for better release.”
On high-volume lines, product orientation and alignment often start in the design phase, noted Anthony Salsone, sales engineer, G&F Systems, Roosevelt, NY. Some vendors offer a variety of belts, including a positive or direct drive or ones made with different composites of materials to customize conveying to a customer’s specifications or a product’s requirements.
“G&F offers a multitude of belt options and transfer designs to reduce waste when handling delicate products,” Mr. Salsone said. “From a zero transfer seamless conveyor design to a tight transfer conveyor design, our conveyors are designed to limit product movement, which greatly reduces product waste.”
Bakers and snack makers should consider the intrinsic relationship between specific belts with various conveyors as well as the products they’re moving along their production lines. As Kenneth King, Ashworth Bros. commercial support manager, pointed out, belting is much more than a component in conveying. “Bakers often get the perception that the conveyor belt is an accessory like a screw or bolt,” he noted. “It behooves them not to consider the conveyor belt the same way. The conveyor belt is a piece of equipment that is being married to the conveyor. If you don’t consider the operation and the process for both pieces of equipment, you may not always get a good marriage between the two. You might spend a lot more money in maintenance time in the long run.”