Managers for many of the Irving Materials Inc. (IMI) plants know about winter production problems too well. Immediately after Thanksgiving, they are challenged to produce warm concrete in winter conditions to keep their customers supplied. With a host of ready-mix concrete plants from Illinois to Ohio, these managers have tried many different methods to keep concrete warm.
So when they had to select a water heating system for their newly renovated ready-mix plant in Indianapolis, they had a plan. The team selected a direct-contact water heater. Earlier this year, IMI finished its first winter season with the new heater, and managers were pleased with its performance.
Working together on design
“IMI is always looking for new products that might help our operations,” says Monte Larimore, IMI's maintenance supervisor for concrete operations in Indiana. So when engineers from Heatec, a Chattanooga, Tenn., manufacturer of water heating equipment, approached Larimore about their new design, he was intrigued. “They were willing to work with me and incorporate some special features I wanted, so I was willing to work with them on a prototype,” he says.
Larimore agreed to install the first production model of Heatec's Firestorm heater, which was introduced in the fourth quarter 2006. Now a year into the process, Larimore believes the collaborative effort worked well for both parties.
Larimore was a believer in the direct-contact style of water heating, but had experienced some problems that he thought could be easily resolved. He wanted to provide a user's insights on several aspects of the heater's key design features. His influence started with the parts list.
“I asked the engineers to specify common wear components that were readily available,” says Larimore. “Now, I can go to my local burner supplier or electrical store to get parts and components. That simplifies things.”
In addition to simplifying parts procurement, Heatec's engineers learned from Larimore's experience with other direct-contact heaters about how to reduce routine maintenance downtime. Larimore was emphatic that he wanted easy access to the heater's packing material and the combustion areas.
“I wanted quick access to the top and bottom of the heater,” the maintenance supervisor says. “We have some other direct-contact heaters at other facilities, but our men don't have access to the inside of the heater.” Larimore believed that quick opening inspection panels would aid his staff in their troubleshooting efforts and also speed up common maintenance work.
As a result, Heatec engineers designed the Firestorm heater with an upper access hatch to the packing area, and a 20-inch manway for full access to the lower half of the heater.
Larimore says these improvements are significant. Along with reducing inspection time, easy access aided production. To ensure proper water heating, it's important to periodically inspect the packing. “You know if you're not getting the water temperature where it needs to be, the packing material is starting to plug,” he says.
Visual inspection of this new heater helped Larimore reduce plant downtime, compared to plants operating direct-fired water heater styles that don't have inspection hatches. To ensure maximum water flow, Larimore's plant repairmen must periodically clean the packing material by cycling an acid mixture through the heater a few times.
The Indy plant eliminated this time-consuming process. Now, the plant repairman opens the upper access hatch to inspect the packing. Then, if the packing media needs cleaning, he can pull it all out and clean it. Of course, then he has to put it back in at the top. In the same manner, if the combustion area becomes dirty, the repairman opens the lower manway to clean it out.
Heated water without added costs
While Larimore is happy from the maintenance side, his plant manager has also been satisfied with productivity. In the design phase, Heatec engineers sized the prototype Firestorm heater's capacity to match IMI's plant production target of 100 to 120 yards per hour. They opted for a unit that would create a water temperature rise of 120° F at a flow rate of 50 gallons per minute. “The heater kept up without batting an eye,” says Larimore.