Elevator workers create a unique solution to getting around extremely long conveyor belts.
Nearly 38 million bushels of wheat and milo are stored each year in the three ADM/Farmland grain elevators in Fort Worth, Texas, U.S. The grain is delivered by truck from North Texas and by rail from the Midwest, on its way to the Gulf by rail for export.
The elevators are owned by Farmland Industries, Inc. but leased and managed by Archer Daniels Midland Co. in an agreement completed last May involving a total of 24 Farmland grain elevators in the United States.
According to Sam Stone, assistant superintendent for ADM/Farmland, the first thing the new management did upon taking over the operations of the three Fort Worth elevators was to look at ways to improve operating efficiency and safety at each facility. The grain elevators were built in the 1950s, and over the years have been expanded and upgraded.
Management immediately noticed an area for improvement at the two Saginaw elevators, so named because of their location in the Saginaw suburb of Fort Worth. (The other Fort Worth elevator is called the Katy Elevator because of its location near the old Katy railroad line.) The length of the open belt conveyors in the head house galleries — each 800 to 900 feet long — limited access to the outside of each belt. Workers had to walk around the entire length of the conveyor to get to the other side. This was not only inconvenient and tiring for employees, Stone said, but it also posed a safety hazard in the event of an emergency.
"We decided we needed a little bit better method for crossing over the conveyors," Stone said.
Because the existing open belt conveyors have a movable tripper, fixed crossovers could not be installed. Most drag conveyors, enclosed belt conveyors or open belt conveyors without a tripper can be installed with fixed crossovers at various places along the belt, but the cost to install new conveyors was prohibitive in this case. So Stone shopped around for a portable "bridge" that could be moved along the length of the conveyor, spanning the width of the belt so that workers could safely cross from one side to the other, but no such product existed in the marketplace, he said. He then had two choices: design and build one in-house or hire a millwright company to do it.
"We can handle this ourselves," his maintenance crew told him.
Maintenance employees Mike Bergdall and Charles Troyer designed and built a portable conveyor crossover that could be used on either side of the tripper, on either belt and to access emergency exits.
"They did a job that would make an engineer proud," Stone said of his crew.
The main structure of the crossover was formed with welded 2-by-4 rectangular tubing supported by triangular plates. Stairs were formed between the plates, and a ladder on the other end slides up to allow the crossover to be moved or can swing up and out of the way. Handrails made of 1-1/2-inch square tubing were installed, and locking casters keep the entire unit from moving.
The first crossover took the two men about two days (a total of about 25 hours) to build. The crew has since built three more units — one for each of the conveyor belts in both Saginaw elevators. The materials for each unit cost about U.S.$250.
Stone submitted the portable conveyor crossover to the U.S.-based Grain Elevator and Processing Society for consideration in its "Idea Exchange," a forum that touts new products and services that improve grain operations. He gave a presentation on the crossover at GEAPS’ Exchange 2002 conference and trade show held earlier this month in Vancouver, British Columbia, Canada.
Stone created plans for the portable conveyor crossover using a computerized drafting program. To request a free copy of the plans, e-mail Stone at firstname.lastname@example.org.
He stressed that these units are not a "one size fits all," and that each crossover would have to be custom made according to the specific height, width and length of each particular conveyor belt. And because the units are so large — each is about 6 feet long — there must be plenty of space around the belt to maneuver the crossover.
"Our workers say it (the crossover) really saves them time," Stone said. "We’ve found where the main traffic areas are along the belt, so we usually don’t move the crossover unless we move the tripper."