Trough-Type Distributor
The original trough type distributors were fabricated from cast iron with a heavy wall rectangular trough. Notches at the top edge allowed the acid to overflow into downcomers also made of cast iron. The downcomers clipped onto the top edge of the trough and directed the acid to a point in the packing. A feed pipe system is required to distribute the acid between the troughs. Orifice plates installed in the feed pipe system ensure even distribution between the troughs. Due to the size of the cast parts, cast iron distributors were only able to achieved about 15 distribution points/m² (1.4 points/ft²).
Cast iron distributors served the industry well for many years but they were not without problems and limitations. Like all trough type distributors the trough must be absolutely level in order to achieve uniform distribution across the trough. The ends of the troughs rested on brick corbels and brick shims were required to level the troughs. Intermediate overhead supports were sometimes required for the longer troughs. Uniform acid distribution in the feed pipe system is also required but this would be affected by the uneven corrosion of the orifice plates used to distribute the flow. The troughs would often fill with sulphate and would require periodic cleaning with was both messy and dangerous. Although the life of a cast iron distributor was acceptable, the material did corrode which meant it would eventually need to be replaced.
The original trough type distributors were fabricated from cast iron with a heavy wall rectangular trough. Notches at the top edge allowed the acid to overflow into downcomers also made of cast iron. The downcomers clipped onto the top edge of the trough and directed the acid to a point in the packing. A feed pipe system is required to distribute the acid between the troughs. Orifice plates installed in the feed pipe system ensure even distribution between the troughs. Due to the size of the cast parts, cast iron distributors were only able to achieved about 15 distribution points/m² (1.4 points/ft²).
Cast iron distributors served the industry well for many years but they were not without problems and limitations. Like all trough type distributors the trough must be absolutely level in order to achieve uniform distribution across the trough. The ends of the troughs rested on brick corbels and brick shims were required to level the troughs. Intermediate overhead supports were sometimes required for the longer troughs. Uniform acid distribution in the feed pipe system is also required but this would be affected by the uneven corrosion of the orifice plates used to distribute the flow. The troughs would often fill with sulphate and would require periodic cleaning with was both messy and dangerous. Although the life of a cast iron distributor was acceptable, the material did corrode which meant it would eventually need to be replaced.