The Pall Ring is an advance on the Raschig Ring, with similar cylindrical dimensions.
Crucially it also has two rows of punched out holes, with fingers or webs turned into the centre of the cylinder, which significantly increases the performance of the packing, in terms of throughput, efficiency and pressure drop.
Capacity versus Pressure Drop
• Most suited in low pressure drop, high capacity applications;
• A range of sizes allows the tower to operate at an optimum efficiency and throughput;
• High degree of randomness;
• Consistent ratio of free and blocked passages, independent of orientation;
• Large surface area : volume ratio augments the rate of liquid film surface renewal to improve mass transfer.
Hold-up and Two-phase Contact
• Promotes highly efficient two-phase contact and distribution;
• A relatively high liquid hold-up promotes high absorption efficiencies, especially in cases where the reaction rates are slow;
• Uninterrupted and consistent passages for gas and liquid flow.
• Open, cross-linked design provides a highly efficient used of the ring’s surface area;
• Robust to variations in liquid and vapour distribution.
•Its internal cross-structure of diametrical spars make it mechanically robust and suitable for use in deep packed beds.