For most people, South Bend, Indiana, is best known as the home of the University of Notre Dame and its famed Fighting Irish football team. The Irish fans always hope the season ends with a chance to play for a national championship, but the operators at Walsh and Kelly's South Bend plant were watching a different type of season come to its close. Just as Notre Dame's fans cherish their program's storied history, the team at Walsh and Kelly would also rely on their past to build a successful future.

The Dillman unified drum is a high quality counterflow design
The Dillman unified drum is a high quality counterflow design offered in both portable and stationary arrangements.

Time for a Change

Walsh and Kelly noticed a growing problem—one that would require a careful decision and serious investment. The South Bend plant's CMI triple drum was approaching the end of its lifecycle. Compounding the issue, the stainless steel ring between the recycle and the burner was wearing away. That component alone could cost the plant's budget upwards of $50,000. Needing a new drum, in addition to a significant repair, the time was right to consider a major retrofit for the plant.

Walsh and Kelly decided to replace their CMI triple drum with a Dillman unified drum. The Dillman UniDrum is often used for new plant packages but can also be used for retrofit jobs, making it a perfect choice for the South Bend replacement. Furthermore, with a capacity ranging from from 200 to 600 TPH (181 to 544 MTPH), the Dillman UniDrum would be an improvement over the plant's old drum.

Bigger and Better

Another consideration was that triple drums are notorious for filling up with reclaimed asphalt pavement (RAP) in the outer chamber. This had been an ongoing problem for the South Bend plant, one they could eliminate with the right replacement. The Dillman unified drum presents a high quality counterflow design. The inlet into the drum allows immediate mixing of recycle with the hot aggregate, bringing the recycle up to temperature and removing any residual moisture. This creates a natural moisture barrier for the recycled material and prevents deposits. Using this new drum, the South Bend plant could expect to expand its use of RAP to between 40 and 45 percent without any problems.

Walsh and Kelly was also able to make use of the existing frame by extending it to fit the Dillman UniDrum's extra-long drum. The drive chain assembly, motor, and reducer were built the same as existing double drum plants, which greatly reduced the downtime and allowed for the drum to be fitted into place within a brief window. In addition to accommodating a high percentage of recycle, the extra-long drum length cut back on the amount of fuel the plant requires because it maximized mixing and drying times.

A Good Swap

Another advantage presented by the Dillman unified drum is its reduced maintenance costs over its expected lifecycle. Dillman introduced the UniDrum as an option for both portable and stationary arrangements, making it one of the sturdier mixers found in today's plants. Whereas the plant's old CMI triple drum was increasing its operational costs in both routine maintenance and energy consumption, as it approached the end of its lifecycle, the Dillman UniDrum is expected to remain a consistent and efficient ingredient to the South Bend plant's future success.

For all its new advantages, though, the Dillman UniDrum looks perfectly at home at the South Bend plant. The total retrofit and upgrade of the plant lasted until April, making the relative ease of the drum's quick installation all the more impressive to Walsh and Kelly. With the plant upgrade complete, Walsh and Kelly plans to make full use of their new Dillman UniDrum, routinely running a high percentage of recycle at a higher capacity. Building on a strong foundation and taking advantage of new innovations, Walsh and Kelly's South Bend plant is poised for continued success.