Tema Engineers offer a range of three fine coal centrifuges in varying capacities. From the H900 and H1000 to the high tonnage BFC150. These centrifuges are typically employed to dewater coal from spirals normally in the size range of 0.1mm to 2mm, although all models can accept much larger particle sizes equally well. Tema fine coal centrifuges are of the horizontally rotating, high gravitational force type. These centrifuges are a continuously operating, scroll/screen basket type in which the slurry solids are retained on the basket and transported from the small diameter end to the large diameter end by means of the angle of inclination of the basket and a scroll. The scroll acts like a screw conveyor spinning at a slightly faster speed than the basket.
Performance / CapacityTema fine coal centrifuges have been proven to provide high capacity with the highest levels of de-watering over two decades. BFC150 fine coal centrifuges can handle over 100 tonnes per hour. Low Product Moisture Tema Fine Coal Centrifuges feature large basket surface areas and are high centrifugal force machines. This results in the driest possible product. Benefits of the fine coal centrifuges include the low cost of ongoing consumables. Centrifuge baskets are an important on-going cost as these need to be changed out every 6 to 12 weeks. Tema fine coal centrifuges are designed with a basket supporting cage built in as part of the centrifuge, allowing for the installation of a light weight screen basket. Competitor designs incorporate this supporting cage into the basket itself resulting in a far heavier and more expensive basket. These fine coal centrifuges feature relatively small drive motors operating efficiently result in lower electricity costs.
Tema fine coal centrifuges have the smallest plan area in the market, together with a choice of hinged door handings allow for ease of CHPP design and low installation cost. The centrifuge operates with low vibration levels and also incorporates vibration damping within the support frame. The assemblies that make up the centrifuge are designed in a modular manner and can be quickly and easily replaced resulting in lower production downtime. Also all lubrication points are easy to access. Over 300 fine coal centrifuges of the Tema – Siebtechnik design have been employed in coal washeries around the world. Over 160 machines have been built by Tema Engineers in Australia with many being exported to remote regions such as Chinese Inner Mongolia. In Australia, in 2008, there were 41 centrifuge installations operating reliably with availabilities approaching 99.5% in between replacement of consumables and planned maintenance. The TEMA horizontal fine coal centrifuge has been well and truly proven in the tough coal environment.
Functions of the fine coal centrifuges:
The coal slurry is fed into the small inner diameter of the scroll and distributed evenly onto the basket through feed ports. The centrifugal force causes the liquid portion of the feed slurry to pass through the screen while the solids form a cake bed which is continuously turned and swept outward. The coal solids are then discharged at the large outer diameter of the screen basket.
Features of the fine coal centrifuges:
- These fine coal centrifuges feature abrasion resistant wear linings. The product compartment is lined with abrasion resistant alumina tiles for long life
- Cyclo Gearbox Speed Reducer. The TEMA cyclo gearbox is designed to have a single input speed with two output speeds. The screen basket / cage assembly both bolt to the reducer housing, thus the screen basket is directly driven, The differential cyclo-gear design allows the output shaft, upon which the scroll is mounted, to rotate slightly faster than the cyclo housing. This causes the difference in speed between the screen basket and the scroll assembly; thus the screw conveyor effect
- Torque Limiter. To provide mechanical protection for the cyclo gearbox, a torque limiting clutch is mounted to the input shaft via a torque arm. A limit switch provides an electrical signal when the overload clutch releases
- Scroll. The abrasion resistance of the TEMA scroll and basket cage have been designed and tested over a number of years for maximum life. Hardfaced steel and high wear alumina tiles are employed together with over sized feed ports to ensure that wear is minimised
- Motor Starting. The main drive motors can be started direct on line (DOL) avoiding the complexity of electronic soft starts or VVVF drives