Ceramic Filter Tube

A ceramic filter tube is a hollow tube of porous ceramic, used as the filter element in equipment that has to separate solids from a liquid or a gas very cleanly. It looks like a plain ceramic pipe, but its wall is deliberately made porous, honeycombed with a fine, even network of tiny channels. That porous wall is the filter. In use the tube is fitted into a housing, and the dirty fluid is put under pressure on one side of the wall; the fluid is forced through the pores to the other side and comes out filtered, while the particles it was carrying are too big to pass and are left behind on the wall. How fine it filters is set by the size of the pores, which can be controlled in manufacture, so the tube can be made to a chosen precision, from simply clarifying a liquid down to holding back very fine particles or even bacteria. Because everything about it is fired ceramic, it filters where the going is hard: in hot fluids, in strong acids or alkalis, and in streams that would dissolve or clog an ordinary filter. It is a precise, rugged, reusable filter.

Three main kinds of job. The first and commonest is liquid-solid separation: pulling suspended solids, precipitates or catalyst fines out of a process liquid to recover a clear filtrate, or to recover the solids, in chemical, pharmaceutical and wastewater work. The second is gas filtration and purification: the same porous wall filters dust and fine particulate out of a gas stream, including hot gases that would destroy a fabric filter, which is useful in high-temperature process and flue-gas cleaning. The third is disinfection, or sterile filtration: made to a fine enough grade, the ceramic pores are small enough to physically strain bacteria out of water, so the tube can produce microbiologically safe water without chemicals, the same principle as a ceramic drinking-water filter, scaled up. Across all three the appeal is the same: a fine, exact filtration that also survives heat, corrosion and repeated cleaning. Tell us the fluid and what you need to remove and we will suggest the grade.

They filter in different ways and at different scales. Granular media, sand, ceramic sand, gravel, is a loose bed of grains; water trickles through the spaces between the grains and the dirt is caught among them. It is simple and cheap and handles large flows, but it is relatively coarse: it clarifies water rather than filtering it to an exact fineness, and the grains just sit loose in a vessel. A ceramic filter tube is a single, solid element with a precisely made porous wall, so it filters much finer and to a defined rating, and it does so as a fixed piece plumbed into a housing. In short, granular media is for bulk clarification of large volumes, while a ceramic tube is for fine, precise separation, recovering a specific solid, polishing a liquid, or sterilising it, often on smaller, more valuable streams. Many plants use both: a sand bed for the rough work and ceramic elements for the fine. Tell us how clean the filtrate must be and we will say which suits.

The tubes are made in a standard range, the WFG series, from WFG-30 to WFG-300, where the number is the outer diameter in millimetres, so from a 30 mm tube up to a 300 mm one, with the inner bore scaling from about 20 up to 230 mm, and a standard length of 1000 mm; several tubes are usually bundled into one housing for the flow needed. Whatever the size, the ceramic gives the same properties: a high, controllable filtration precision; strong resistance to acids and alkalis; thermal stability with no softening or deformation when hot; high mechanical strength; and a clean, non-toxic surface with good sealing at the ends. Cleaning is one of its best features. When the pores clog and the flow drops, the tube is regenerated rather than thrown away, most simply by back-flushing, reversing the flow to push the trapped solids back out of the pores, and where needed by chemical cleaning or firing. Done regularly, this returns the tube to near-new and it serves for a long time. Send us the fluid, the flow and the vessel and we will specify the tubes.