Plastic Hump Support

A plastic hump support is a PP plate that sits low in a packed column and does the two jobs every packing support must. It is moulded as a run of raised, hollow beams studded with holes. Its structural job is to bear the whole load pressing down on it, the mass of the packing plus the liquid working its way through, while resting on the support ring, and to do so without bowing. Its flow job comes from the beam shape: rather than making the vapour and the draining liquid fight through one set of holes, it separates them. The vapour is jetted out sideways through the holes high on the beams, clear of the liquid, and the liquid trickles down to the base of the beams and drains from there. Splitting the paths means the plate need not be crowded with openings, it stays mostly clear, so it carries a large throughput before choking and steals very little draught. As a plastic part it is light, easy to manoeuvre into place and immune to corrosion, but the polypropylene keeps it to cooler service.

The support plate is offered in three materials, and the choice follows the temperature and the chemistry. Polypropylene, the plastic version here, is the light, low-cost option: it resists most acids and alkalis and is easy to handle, but it softens with heat, so it is kept to roughly 90 degrees. Stainless, grade 304 or 316L, takes over when the gas runs hot or the bed is heavy, holding its strength at temperatures and pressures no plastic could reach. Ceramic is chosen where the service is both corrosive and abrasive, or very hot, and where its brittleness can be worked around. As a rule: PP for cool, corrosive, weight- or cost-sensitive columns; stainless for hot, heavy-load duty; ceramic for the most aggressive, abrasive chemistry. Tell us the temperature, the load and what the gas carries, and we will name the material.

The beams are the working part. Each is a hollow ridge pierced with rows of holes, and those holes act as gas jets: they inject the rising vapour into the bed evenly and keep the open area high, while the solid beam between them carries the mechanical load, so the plate is both strong and very open. Clogging is the thing a support plate must avoid, and the shape and the loading method both help. The many small holes are sized so that packing pieces bridge across them rather than dropping through, and there is a simple installation rule that prevents blockage: lay a first course of large packing, about 300 millimetres deep, straight onto the plate, and only then tip the smaller pieces on top. The big pieces hold the small ones clear of the holes, so drainage stays free and the plate does not blind, which matters most with small packing under about DN25. Ask us and we will advise the hole pattern and the loading for your packing.

A plastic hump support suits packed towers whose gas is corrosive but not especially hot, the case where a PP plate can replace a metal one. Refiners and petrochemical plants put it beneath the bed in distillation and absorption columns; chemical works use it in acid and alkali scrubbers and in solvent-recovery towers; and fertiliser and gas producers fit it in ammonia towers and in oxygen and nitrogen units. Its role never changes, to shoulder the bed and its liquid, and to hand the vapour and drainage a broad, low-drag route so the plate itself never caps the column's throughput. For a wide vessel it is delivered as panels sized to fit through the manhole and bolted up inside, sparing you a shell opening. Give us the column, the packing and the operating duty, and we will draw up the plate.