Monday 12th April 2021 Font size:

KUMERA GEARBOXES: How a customized solution can increase reliability and reduce energy costs.

Monday, March 1st, 2021

Getriebe lackiert 002

Powerful conveyors and their drive systems have a key role in surface mining. In ore mines, conveyor belts up to several kilometers long transport ore for further processing or transportation and reduce labor burden. The operational safety and reliability of the systems are of great importance since delays or shutdowns due to damage can cause immense downtime costs.

Environmental hazards such as extreme weather conditions and fluctuations, dust, and dirt pollution, and falling rocks must also be considered for operational safety. Systems are often installed in impassable locations so low-maintenance concepts are required. In the event of service or damage, the downtime should be as short as possible.

Three-phase AC motors with the following gear variants are typically used as drive concepts for the conveyor belt systems:

  • Standard gear with or without fan
    Advantage: Fast availability and inexpensive

      Disadvantage:   Small outputs up to 1,000 kW
For gear ratios greater than 16:1 in 3-stage design, which results in high power losses.Less possibility of variation in terms of installation and environmental conditions.
Additional lubrication and cooling units are usually required for heat dissipation.

Three-phase AC motors with the following gear variants are typically used as drive concepts for the conveyor belt systems:

  • Standard gear with or without fan
    Advantage: Fast availability and inexpensive

Disadvantage:   Small outputs up to 1,000 kW
For gear ratios greater than 16:1 in 3-stage design, which results in high power losses. Less possibility of variation in terms of installation and environmental conditions.
Additional lubrication and cooling units are usually required for heat dissipation.

  • KUMERA customized gears

Advantage:  Optimized drive design for the respective application and the specified environmental conditions.

Outputs over 2,500 kW are possible.

In the 2-stage design, ratios greater than 20:1 are possible, which reduces the power losses by up to 30% compared to 3-stage gearboxes.

Large variety of options, including universal installation options thanks to the double foot design.

Compact design through the flange output shaft.

No additional lubrication and cooling system.

Higher operational safety thanks to a significantly lower number of components at risk of failure.

Disadvantage:   Higher design effort and more complicated gear housing design due to the internal oil routing. This means higher costs, which, however, are partially offset by saving the oil supply system.

CIMG1287

The gearboxes are mounted on a base frame as a drive unit together with all additional components (e.g., brakes, torque support, etc.) and flanged on the belt drums. Depending on the power requirement, a conveyor belt is equipped with one or two driven belt drums, whereby each drive drum can be equipped with a drive on one or both sides. A conveyor belt is thus equipped with up to four drive units. A great advantage of having several drives per conveyor belt is that if one drive fails, the system can continue to operate, albeit with a reduced delivery rate, until the defective drive is repaired or replaced. Another advantage in connection with the universal gearbox design is that in the event of a defect with a replacement gearbox any damage, regardless of the gearbox position in the system, can be repaired at significantly lower costs than if the conveyor belt were driven by just one large drive.

KUMERA conveyor belt drives are designed as a two-stage design when possible. Compared to a three-stage version with standard gear units, this has the advantage of 1% better efficiency (approx. 98% instead of 97%). What does not sound like much at first glance, however, turns out to be an ecologically and commercially significant advantage.

DSC00056

KUMERA powered overland conveyor in operation in Chile.

For example, a KUMERA conveyor belt with 10 MW drive power (4 drives at 2,500 kW each), currently in use in a copper mine in Chile, has a savings of approximately 100 kW/h in motor operation by an efficiency increase of 1%. For a conveyor system consisting of three conveyor belts, with a system utilization of 80% on average and an operating time of 16 hours/day and 250 days/year, this means an energy savings of approximately 960 MW per year. If still considering a system utilization of 80% but 24/7 operation time and 14 days downtime for maintenance per year the savings ending up to 2,016 MW.

In many applications the systems convey the material downhill, which means the operation is in generator mode. The higher efficiency means the systems will generate approximately 100 kW/hour of power more than a three-stage version with standard gear units.

IN20081103-01_300dpi

KUMERA endeavors to support plant manufacturers in the implementation of their drive concepts with the best possible gear design. KUMERA also offers support to system operators and tailor-made drive concepts for the renewal and improvement of operational safety and increased performance of conveyor belt drives. The KUMERA belt drives are subject to continuous improvement. At present, new concepts are nearing production, through which both greater power density and an increase in operational reliability under thermal performance limits will be achieved.

Author:Heinz-Peter Ehren

Dr. Heinz-Peter Ehren, Managing Director,  KUMERA Getriebe GmbH

https://kumera.com
< go back
Kumera
Famur 2021
IME 2021
Media Packs
Commodities
Advertise here
Publications