When a bearing failure caused extensive damage to the girth gear of a rotary kiln at Duna-Dráva Cement in Vác, Hungary, SEW-Eurodrive supplied a high-performance replacement. The plant, part of Heidelberg Materials, relies on the rotary kiln to produce around 2,400 metric tons of cement clinker per day. To ensure continued production, the worn gear and pinion were replaced with a segmented girth gear made of high-strength ADI (austempered ductile iron).

Rotary kilns benefit from optimized drive design

The kiln in Vác features a 4.2-meter diameter rotary kiln where clinker is produced at high temperatures. A robust drive system delivers 350 kilowatts of power via an asynchronous motor and industrial gear unit. A flexible coupling and a pinion with independent bearing support transfer torque to the girth gear, which rotates the kiln shell. The existing setup suffered from wear due to pinion misalignment, prompting a complete drive system upgrade.

Segmented girth gear with ADI improves performance

SEW-Eurodrive's solution includes a 6.1-meter segmented girth gear with a width of 300 millimeters and a gear module of 40. The number of teeth was reduced to 152. The use of ADI offers notable advantages: it provides a tensile strength above 1,000 megapascals and elongation above five percent, resulting in improved resistance to wear and continuous mechanical loads. Compared to conventional cast steel, ADI significantly enhances the durability of rotary kiln drives.

Compact segment design enhances rotary kilns handling and quality

Unlike conventional systems with large gear segments, SEW-Eurodrive uses a modular approach. Individual gear segments, each one to two meters in size, simplify transportation, installation, and replacement. This consistent design supports high manufacturing precision across various kiln sizes and reduces the complexity of maintenance.

Material and structural savings support long-term operation

Thanks to the optimized geometry, the new girth gear requires less material. Reducing the width from 500 millimeters to 300 millimeters and increasing the gear module not only lowered production costs but also cut lubrication demand and maintenance effort. The precision of pitch and alignment minimizes vibration and mechanical stress, extending the overall service life of rotary kilns. This solution underlines how targeted material selection and structural design can improve the performance and reliability of rotary kiln drive systems in cement production.