Raw Material Extraction and Processing
KRW large bearings are used worldwide in almost all areas of raw material extraction, preparation and processing. The extreme operating conditions in these areas demand maximum wear resistance and longevity from the bearings. In process plants where downtimes and repairs far exceed the costs for a bearing, it is immensely important for the plant operator to be able to rely on the functionality and availability of bearings. Whether in coal production, ore crushing and processing or the cement industry, KRW bearings have stood for reliability in these industries for decades.
KRW bearings are used where the most difficult conditions for a rolling bearing prevail. Through decades of experience, we have further developed our bearings in many areas and optimised them for numerous applications. The spectrum ranges from improved materials and heat treatments to specifically adapted design features and application-optimised special constructions.
Bowl mills are used for the coarse comminution of ores and rocks. Large bearings are used in several rollers arranged in a star shape, which are also directly exposed to the high basic loads as well as all impacts and shocks of the shredding process. To cope with these loads, KRW bearings are not only optimised for load ratings, but are almost exclusively made from case-hardened special steels.
Bearings for roller presses are subject to extreme loads. The comminution of particles of varying hardness and size generates both high base loads and load peaks that are always difficult to calculate. Many years of development and experience are necessary for the bearing arrangement to withstand these loads. KRW bearings are optimised in their internal geometry, material, surface treatment and load rating to meet precisely these challenges.
Piston Pumps and Diaphragm Pumps
Large piston and diaphragm pumps are indispensable in mine drainage in the mining industry. The so-called hydraulic transport of solids, in which diaphragm pumps are used to transport ores over hundreds of kilometres, is also playing an increasingly important role in the development of ore deposits. The low energy requirement compared to conventional conveyor technology or road transport as well as the impact on the environment are only two of the reasons for the spread of this technology. The bearings within these pumps are subject to high loads and demand one hundred percent process reliability over more than ten years. No matter whether connecting rod bearing, support bearing or crosshead bearing, the installation space is very limited and demands the optimum from engineering and material selection to production technology.
Tube Dryer/Tube Bundle Dryer
Hardly any system is more effective in reducing the water content of coal or other materials than a tube dryer. The product to be dried is transported through a bundle of tubes up to 10 metres long, steam-heated up to 180 °C. Contact with the hot tubes dries the product while it is transported axially. The longitudinal expansion that such a wave experiences through active heating is sometimes in the range of several centimetres. In addition to compensating for shaft deflection, the bearings must reliably ensure this compensation over many years. Corrosion and contamination of the floating bearing seat are therefore often accompanied by total failure of the plant. For such critical cases, KRW offers the ACB bearing series, which represents a more reliable alternative to the well-known spherical roller bearing in this application.
Services and Engineering
In no other area is the maintenance or replacement of bearings as difficult as in raw material extraction and processing. The systems are huge and often located in poorly developed and difficult to access regions. This is one of the reasons why KRW has been a development partner from the very beginning. The actual bearings costs are determined at the beginning of the planning and during the construction phase.more