Plastic Hexagonal Ring

A hexagonal ring is a plastic packing that looks like a plain short cylinder from the outside but is quite different within. Reaching in from the wall are six thin blades that join at the axis, so the cross-section reads as a six-pointed star. Those six blades do the real work. They divide the ring into six wedge channels and pull the falling liquid off the outer wall and into the body of the packing, which puts far more wetted surface to use than a hollow ring ever could. Every edge and junction where the blades meet becomes a spot where the liquid film is torn and re-spread, so the liquid keeps renewing rather than running in tired streaks. Meanwhile the outer wall is left open, so gas passes easily and the pressure drop stays modest.

Hexagonal rings go into the same columns as the other high-performance plastic rings: separation, absorption and washing towers in petroleum refining, general chemicals, chlor-alkali plants, gas works and environmental treatment. They are dumped into the tower as a random fill, and their job is to bring gas and liquid together over a large surface while letting both flow through freely. Because the plastic resists acids, alkalis and salts, they suit the corrosive streams these plants run, and because the star interior spreads liquid so well, they hold their efficiency across a range of loads. Any duty that would use a Pall or step ring can use a hexagonal ring instead.

Which plastic to order comes down to how hot and how aggressive your stream is. For the majority of jobs, ordinary acids, alkalis and salts at modest temperature, polypropylene is the sensible, low-cost default, and a glass-reinforced version is on hand when the bed needs more stiffness. When chlorinated or acidic media run warm, the chlorinated grade CPVC buys extra heat tolerance over standard PVC, and for the hottest or most oxidising service PVDF is the premium answer. As a working range the media can sit anywhere from about 60 up to 150 degrees, with the ceiling set by the grade you pick. Send the stream details over and the right resin can be settled quickly.

Set a hexagonal ring beside a Pall ring and the difference is all on the inside. A Pall ring keeps a mostly open middle, with windows cut in the wall and small tongues bent inward to break up the flow. A hexagonal ring instead fills its centre with a six-blade star, so it carries much more surface within the ring and offers many more points where liquid is redistributed. That tends to give sharper separation and more even wetting for a given size, at the cost of a slightly denser packing and a little more pressure drop than the very open Pall. Where a column needs the extra contact area and distribution, the hexagonal ring is the stronger choice; where raw openness and the lowest pressure drop rule, the Pall ring holds its own. We can compare the two for your column if you send the details.