... PVC, CPVC,etc.) 1.high free volume 2.low pressure drop 3.low mass-transfer unit height Plastic Cascade RingIntroduction ... high free volume, low pressure drop, low mass-transfer unit height, high flooding point, uniform gas-liquid contact, small specific ... towers in petroleum industry, chemical industry, alkali-Chloride industry, coal gas industry and environmental protection, etc. Technical data: D*H ...