An additional 350,000 t/mth of coal production has been made possible at the Chinese Sandaogou coal mine in Shaanxi province thanks to the the a CPC 1600 AFC coupling from Voith. This fluid coupling can continuously transmit up to 1,600 kW. That represents 60% more power than with standard fluid couplings of comparable installation space. With the CPC 1600 coupling, Voith says it can offer its mining customers a robust but compact design and that its engineers achieved this increase in power density “with the innovative XL profile design turbine wheel.”
To be able to efficiently mine a coal face measuring 7 m high, 350 m wide and more than 3 km long, the operator of the Sandaogou coal mine needed equipment that is considerably more powerful. The challenge was that the existing drive system was not able to transfer the necessary power to the conveyor. China Coal Zhangjiakou Coal Mining Machinery, one of the largest Chinese OEMs and the main equipment supplier to the Sandaogou coal mine, chose a drive system with the Voith CPC 1600. The couplings combine maximum power transmission and small size. Orders for three CPC 1600s have been delivered and are currently in use in the Chinese Sandaogou coal mine.
The CPC 1600 protects motors and drive components against damage. “Since there is no mechanical connection between the input side and the output side of the coupling, we can run our motors up to speed without load. We switch the motors on one after another to avoid high current demands that would place an unnecessary load on our grid power system”, said Tong Xiangyang, Team Leader of a coal face in the Sandaogou coal mine. The CPC 1600 fluid coupling also protects the motors against overload. This overload protection is possible since the fill-controlled fluid couplings simply slip because of the hydrodynamic principle. This slip protects the drive components and the chain of the AFC against damage. Consequently, the fluid coupling maximises the availability of the entire system and its productivity.
“With the CPC 1600, users in Sandaogou can perform as many startups in a row as they wish”, explains Tang Min, General Manager of Startup Components at Voith in China. This is important, for example, in order to break free a heavily loaded conveyor. In this way, the personnel avoid needing to manually clear the overloaded system, which is time-consuming and results in costly, unplanned downtime.” There have been no unplanned downtimes and production is running at a considerably higher efficiency since the new AFC was commissioned in May 2012.
The Voith CPC 1600 hydrodynamic fluid coupling uses water as the operating medium. As a result, users avoid expensive explosion protection measures. The fluid coupling power transmission is alo wear-free and requires little maintenance. These features result in extremely long life cycles. Voith states that its fluid couplings are insensitive to environmental effects such as dust, dirt and moisture, making them ideally suited for rough use in the underground coal mining industry.
The Chinese coal mine at Sandaogou is located in Shaanxi province, about 700 km west of Beijing. Currently, the mine has an annual output of 10 Mt from two longwall coal faces. Before using Voith fluid couplings at one of the coal faces, the mine produced 5.8 Mt/y. Thanks to the new couplings on one AFC, output has now risen by an additional 350,000 t/mth. Taken over a year, this translates into an annual production increase of 4.2 Mt of coal. Production at the face concerned has therefore more than doubled.