Applications
6.3.7 Sewage Treatment Chain
(Rectangular Sludge Collector)
Large conveyance: Sewage treatment equipment
Application Example One of main uses of large pitch conveyor chain is in water treatment facili- ties. In a large sewage treatment facility, sewage goes through several tanks in which solid wastes are eliminated by deposition and flotation. In the silt tank, sand and dirt are removed using vacuum or V-buckets. In the settling tank, sludge in the water, or on its surface, is scraped to the exit with “flights” (boards) installed between two strands of chains at intervals of 3 m (Figure 6.26). Sewage Treatment Chain (ACS Chain) is used in this process (Figure 6.27). Accumulated dirt is removed with pumps. Cast iron chains were once used in sewage treatment facilities. In such a cor- rosive environment, chain deterioration could not be avoided. As the volume of chain material decreased due to corrosion, wear was accelerated. To offset the loss of material due to corrosion, cast iron chains became quite heavy, yet the tension required in water-treatment applications did not justify the use of a chain with such high tensile strength. In the mid-1960s, ACS stainless steel chains were developed in Japan espe- cially for water treatment facilities. The stainless steel construction assured excellent corrosion resistance, so there was no need for extra-heavy cast iron chains. Because of their superior functions, ACS chains have gained wide acceptance. This chain is also used to convey corrosive objects in general scraper conveyors.
Figure 6.26 Sewage Treatment Chain with Flights Installed
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