... engineering, elaborate chemical engineering, fertilizer, sulphuric acid, smelting,electrical power and environmental protection industries 8) Specification: Φ100 ¨C 7 ... of transfer units per meter, low HTU, depending on the systems 2) Small pressure drop per meter packed height 3 ... number of transfer units per meter, low HTU, depending on the systems 2) Minimum pressure drop, typically 2 - 4mBar/m ...