Hydrocarbon Cleaning Impresses Exhaust System Company

For optimum functionality, components of the urea solution dosing devices used in selective catalytic reduction (SCR) systems must adhere to strict cleanliness standards. To reach this level, Cummins Emission Solutions relies on an Ecoclean EcoCcore machine in its plant in Juarez, Mexico. Operating with a hydrocarbon cleaning medium, the EcoCcore is well suited for Cummins’ application, providing improvements in turnaround times, process reliability and cost efficiency.

Cummins Emission Solutions manufactures exhaust aftertreatment systems for diesel engines. These systems are employed in both commercial vehicles and machinery. Its portfolio is comprised of feeding and dosing units for urea solutions, which are a key element in the SCR systems designed to reduce nitrogen oxide (NOx) emissions. Cummins Juarez Emission Solutions, established in 2014 in the Mexican city of Ciudad Juárez, is among the sites where these feeding and dosing systems are built.

Cleanliness as a Functional Must

The urea solution is atomized as finely as possible as it gets injected into the exhaust stream of the SRC system in a metered flow.

“Part cleanliness plays a key role for the optimum functionality of our dosing system,” says Hugo E. Pérez, manager of production technology and new product launches at Cummins Juarez Emission Solutions. He explains that the components become contaminated with machining oils and grease as well as particles during manufacturing. One challenge with such parts, which are made of various steel alloys, lies in cleaning hard-to-reach interior bores.

So, when it came to selecting a cleaning machine for these components, the company turned to various equipment manufacturers with a priority list topped by high cleaning performance, high throughput and cost efficiency. 

Water-free Operation a Key Additional Criterion

When talking with Ecoclean, the company’s project managers opted for an EcoCcore because the system can work with nonhydrogenated hydrocarbon or modified alcohol. Their choice was prompted by the cleanliness results achieved in the cleaning trials as well as by the overall equipment design.

“Cummins Juarez uses aqueous cleaning systems a lot. As Ciudad Juarez is located in the Chihuahuan desert where water is scarce, the machine's water-free operating process proved a major advantage,” Pérez says. “Its integrated reconditioning feature allows us to regenerate the solvent quite well, so that we can use the medium for a long time without extra maintenance requirements or replacement.”

Modern Technology for High Cleanliness

The EcoCcore implemented at Cummins Juarez runs with halogen-free hydrocarbon and operates in a full vacuum. It is a s single-chamber system that comes with such standard features as two stainless steel flood tanks for pre-cleaning and fine cleaning, heat recovery, full-flow and bypass filtration, plus a high-performance distillation circuit.

The standard pre-vapor degreasing function also contributes to high part cleanliness. Here, the solvent contaminated with oil is not sent to the flood tanks as is customary; instead, it is transferred directly into the distillation system. This minimizes oil contamination in the flood tank and oil enrichment of the hydrocarbon medium, respectively; thus optimizing degreasing performance.

In addition to standard injection flood washing, the system also provides ultrasonic cleaning which can be activated concurrently with filtration. Removed particles will thus be discharged during the cleaning process and cannot settle in the work chamber. A frequency-controlled rotary drive provides the rotation and precision positioning of product carriers.

“Thanks to its vacuum operation, the diverse cleaning modes, the rotating device and vacuum drying, this single-chamber unit provides excellent performance and achieves a very satisfactory cleaning result,” Pérez says. 

High Throughput and Short Cycle Time

At Cummins Juarez, the parts are arranged in part carriers for cleaning, which are placed on the machine’s conveyor system and automatically loaded into the work chamber. The EcoCcore chamber is designed for cleaning containers measuring up to 670 × 480 × 400 mm and a maximum load weight of 200 kg. The large batch size allows multiple part carriers to be stacked in one single load combined with nonstop operations of the machine during three shifts. This process helps to achieve the desired high throughput rate.

Consistent with the diversity of handled parts, Cummins uses nine of the 16 different part-specific cleaning programs on the machine. In this way, the various process parameters (for example, treatment times and intervals for injection flood washing and vapor degreasing, ultrasonic power level and duration, drying settings) can be optimally adapted to the specific product being cleaned.

The program is manually selected by the operator but starts automatically once the door of the work chamber has closed. Cleaning times vary between six and eight minutes per wash load, depending on the program. These fairly short cycles further ensure that throughput specifications are met and hence, per-part cleaning costs are minimized.

Small Footprint Saves Production Floor Space

With its dimensions of 4663 × 1938 mm, the EcoCcore occupies only about 9 square meters of production floor space.

“The EcoCcore appears small when compared to other manufacturers’ cleaning equipment, but this small machine delivers better performance than substantially larger systems and is, therefore, well worth the investment,” Pérez says.