Eagle Materials’ La Salle, Ill., cement facility overcame a severe blockage of Type I cement in its 80,000-ton-capacity storage silo by employing an innovative pneumatic cleaning technology from Martin Engineering. After a support cable on the reclaim screw conveyor came loose at the plant, it sent thousands of pounds of material down into the silo at once, resulting in the blockage. However, with the unique whip design of the cleaning equipment and around-the-clock dedication from a Martin Engineering crew, the buildup was efficiently cleared and loaded out, allowing repair personnel to set up a crane and lift the auger back into position.
Like most cement manufacturers, the plant uses large storage vessels to hold finished material until it’s ready for shipment. At the LaSalle facility, the domed storage unit is 99-ft. tall and 186-ft. in diameter. During the course of normal operations, the cable connectors on the reclaim screw worked themselves loose, causing the auger to fall onto the pile and halting the flow of material. The only way to rectify the situation was to position a crane over the top and lift the conveyor out, so the cable could be reattached. But first, operators needed to clear out enough material to access the disabled equipment, a massive task in light of the nearly full dome.
“Our first step was coming up with a plan to tackle the load-out job,” stated Chief Chemist and Quality Control Manager Kevin Jensen. “We needed to remove a significant amount of material in order to make the repair, and there was just no easy way to go about it.”
Jensen contacted Martin Engineering of Neponset, Ill., for assistance, and technicians were on site the next day to inspect the situation. After reviewing various options, it was determined that the best approach was to employ the Martin Heavy Duty Whip, one of several technologies making up the company’s Silo Solutions product line.
Powered by compressed air, the whip’s patented gyro motor can use a variety of flails and cutting edges to knock down accumulated material without damaging storage vessels. An abrasion-resistant steel chain is best suited for most applications, with a non-sparking brass chain for combustible materials. Urethane flails can also be employed to protect lined vessels that could be susceptible to damage from metal tools. Additionally, the modular boom of the Martin Heavy Duty Whip extends up to 28 ft. and can clean vessels up to 60 ft. in diameter from a central opening of just 18 in.
“With this technology, there’s no need to send a man inside and risk injury,” observed Martin Engineering Territory Manager Jim Densberger. “The equipment can be set up quickly outside the vessel, and it’s portable enough to move easily around various bin sizes and shapes.” In most cases, the technique allows material to be recaptured and returned to the material stream.
With safety harnesses in place, Martin Engineering technicians secured the equipment through an access hatch at the top of the dome. Although the company’s silo cleaning crews are OSHA and MSHA certified for confined space entry, a remote control from outside the vessel was used to safely guide the head. The two-man crew lowered the whip through an opening created in the blockage, then worked their way downward from above, dislodging material as they went. By undercutting the wall accumulation, it eventually began falling in sections from its own weight.
The material was loaded out with normal operating procedures. “During the process, we were able to use our auto load-out system from the bottom of the dome, because the material being knocked down fell primarily in the center,” recalled Jensen. “There was no need to transfer cement in the tunnel, and that helped minimize the disruption.”
With the reclaim conveyor repaired and the process back up and running, Jensen remarked that “the crew’s performance was excellent. Martin Engineering was very responsive, and provided an innovative solution to the problem. We had good communication throughout, and all work was done in a safe manner.”
Founded in 1964, Eagle Materials is one of the nation’s largest cement providers, with four plants supplying a combined total of about 4 million tons annually. The company’s Illinois Cement facility in LaSalle manufactures approximately 1.1 million tons each year.
