The major conveying success story in the 1990s and into the 21st century is the material handling industry's rapid adoption of internally powered drum motors as the conveyor drive of choice. Virtually every industry, from agriculture, mining and mail order to automotive, food and beverage have benefited by the adoption of the high efficiency motorized pulleys to replace conventional conveyor drive systems. Gone forever are the sprockets, chains and belts, motors, gear boxes and pillow blocks that require an inordinate amount of housekeeping, maintenance and repair.
Even more dramatic is the food processing industry's rush to apply and retrofit drum motors wherever and whenever the opportunity becomes available. The industry's response may require a change in definition; drum motors no longer replace conventional drives - they are the conventional drive systems for the food processing industry.
For example:
•Short Run Conveyor Survives Harsh Environment: Fish processing conveyors, powered by drum motors, up efficiency of Mississippi catfish farm.
• Chocolate Maker Virtually Eliminates Maintenance: Sealed-in lubrication and elimination of external drive components simplify washdown and virtually eliminate the need for routine maintenance.
• Nut Packer Picks Self Powered Drum Motors For Sanitation Benefits: Processing walnuts is now contamination free using a hermetically sealed drum motor powered conveying system.
• Automated Fish Fillet Graders Uptime Increased, Maintenance Costs Reduced: Another Mississippi catfish processor eliminates costly, time-consuming maintenance of conveyor drives on fish fillet graders. Processing productivity increased with dependable conveyor drive system.
In each and every example, major concerns regarding operating efficiency, maintenance costs and contamination were resolved by opting for the self-contained drum motors as the conveyor driving force. More on the applications later.
Drum Motor Anatomy
Drum motors, such as those from Van der Graaf, Inc., Brampton, Ontario, are ideally suited for food processing where white powder coating and stainless steel components, special lubricants, lagging and seals are a must to meet stringent USDA and FDA sanitation requirements. All moving parts are enclosed within the outer shell eliminating the need for continual adjustment and yearly maintenance common with external drive systems. The motor rotates two-stage gearing that transmits power to the outer shell through a final gear ring that is fixed to the rotating shell. All internal components are immersed in a food-grade oil bath that lubricates and cools. One oil change is recommended every 50,000 hours of operation, and can be done without removing the drum motor from the conveyor.
Application Details
Here are a few additional details of the above applications:
• Short Run Conveyor Survives Harsh Environment: Delta Pride Catfish, Inc., Indianola, Mississippi, was established in 1981 when a group of Mississippi catfish farmers decided to work together to process and market catfish products. The farmer-owned company is one of America's first catfish processors delivering about 1.5 million pounds of live fish per week. Delta Pride offers a variety of products for the discerning chef, retailer and consumer - from whole fish to fillets to nuggets and even side items including hushpuppies and corn fritters. Value-added additions are specially breaded, bakeable and marinated products. To guarantee the utmost freshness and quality, all products are processed quickly and shipped refrigerated or frozen.
David Peace of Delta Pride explains, "Our thirteen (13) processing lines, each portioned by a grading machine, are exposed to an extremely harsh environment due to frequent high-pressure caustic wash downs. The machines were powered by 3/4hp motors and gear boxes that required constant maintenance and repair. We spent over $3,500 per week maintaining the chains, sprockets, external gear boxes and electric motors -- and this did not include the cost of lost production and hourly wages."
"Conveyor Technology retrofitted our separators with Van der Graaf's internally-powered motorized pulleys over seven years ago, and they are all in service today. Since their installation we have performed zero maintenance and there has been no downtime associated to drive failure. Today, our cost savings has surpassed one million dollars."
• Chocolate Maker Virtually Eliminates Maintenance: At Blommer Chocolate Company, Greenville, Pa., bulk conveyors are used to process nearly two million pounds of cocoa beans every week. The conveyors operate three shifts a day, six days a week, year round. Incoming beans are received by rail car or over-the-road bulk trailers and stored in five large silos. When received the beans are saturated with abrasive dust that is hard on bearings. The first cleaning stage screens them to remove any remaining sticks, stones, and pieces of pod and stems. The conveyors must operate continuously in the harsh, dusty conditions. As the beans are released from the storage silo, they are transported through the screening/cleaning process and then onto the roaster by the hardest working conveyors in the plant.
Terry Grill, Plant Engineer, states, "We initially chose the internally-driven drum motor, because of the tight quarters where the conveyors must operate. We have experienced zero downtime in over eight years of using the drum motors -- an unexpected bonus. Also, in the early days of this operation, shaft mounted gear motor or gear motor roller chain and chain safety cover required constant maintenance due to the dust and other airborne contaminants. Now, Van der Graaf drum motors are a standard specification item for our systems. The bottom line is we virtually eliminated maintenance and associated downtime by choosing the drum motors."
• Nut Packer Picks Self Powered Drum Motors For Sanitation Benefits: Diamond Growers, Stockton, California is North America's largest nut producing plant under one roof. Their engineers are responsible for over 20 miles of conveyor systems that transport products from just picked to packaged and ready to ship.
Processing nuts is hard on conveyor drive parts due to dusty shell fragments that are highly abrasive. The drum motor design had many advantages over conventional drives when you consider the hundreds of drives it takes to power 20 miles of belt conveyors. Diamond installed and tested two other drives before selecting the drum motors. The Van der Graaf drives exhibited superior performance and met all of our requirements; the other drives could not meet the criteria. Gradually all of the existing pulley drives will be replaced with drum motor units.
Dave Fastenau, Industrial Engineer for Diamond Growers explains, "We like the self-contained, internally-driven pulleys because of compactness, safety, sanitation, and they are easy to install. Our conveyors are designed around their mounting style. The drum motors are so reliable we have virtually eliminated downtime due to pulley failure. We have so many units in our plant that it is easy to swap them out in the unlikely event of a breakdown. As an added bonus the leak-free oil seals allow us to operate without drip pans. You could not do that with conventional motor, chain, gear box drives or even with competitive makes of motorized pulleys. We have standardized on drum motors."
• Automated Fish Fillet Graders Uptime Increased, Maintenance Costs Reduced: America's Catch, Inc., Itta Bena, Mississippi, is a vertically integrated catfish processor that maintains their own quality control standards from the hatchery to the consumer. The catfish are raised from fingerlings and kept in a controlled environment for the next 18 months. The ponds are close to the plant so they can be monitored constantly to assure consistent quality.
The catfish are kept alive until the minute they are processed making them among the freshest fish available. The entire production process takes less than 30 minutes thanks to our automated plant. Then the catfish are placed on ice or individually quick-frozen to preserve exceptional taste. America's Catch produces fresh, frozen and breaded whole dressed fish, nuggets, strips and steaks. Specialty items include marinated fillets and seasoned retail items.
Phil Craft, Plant Manager for America's Catch discusses the benefits from switching to Van der Graaf motorized pulleys. "We have four (4) scan graders in our processing plant that were in constant need of maintenance and repair. We spent an average of $1700 per month maintaining the conventional drives that have exposed chains, sprockets, external gear boxes and motors. Since the internally-powered drum motors were installed, the monthly cost to maintain the drives has been reduced significantly -- down to $41.66."
"The new drives have been extremely dependable. We have been able to avoid costly downtime that translates into increased plant productivity."
USDA/FDA Drum Motors
Van der Graaf USDA/FDA drum motors are hermetically sealed in a food-grade oil bath and ideally suited for applications requiring daily high-pressure washdown and acid or alkaline power washings. White USDA approved lagging is available for positive belt traction for extending belt life and moving products efficiently.
Motor installation is quick and easy requiring less than half the time needed to install conventional exposed drives. The motor's compact and low-profile design eliminates all external parts, such as: motors, gear boxes, chains or belts, pillow block bearings and associated guards.
The internal AGMA 12 rated gears are made of high alloy steel with precision cut and honed teeth - reducing noise levels to lower than OSHA requirements. Efficient and reliable, the motors run at 96 percent efficiency, saving up to 30 percent on power consumption when compared to exposed drives. Maintenance needs are minimal requiring an oil change every 50,000 hours.
USDA Dairy 3A Approved units are available in 5.0, 6.5 and 8.5-inch diameters with speeds ranging from 23 to 1369 ft/min and horsepowers ranging from 0.13 to 5.5 hp. All Stainless Steel and Stainless Steel Plated units are available with shell diameters from 3.9 to 19.69 inches with horsepowers ranging from 0.11 to 40 hp. Standard face widths range from 9.84 to 62.99 inches depending on motor size. Standard drum speeds are fixed and range from 23 to 1369 ft/min to match an unlimited number of applications.
