Porous Ceramic Filters

Refractron Technologies Corp. is a leading manufacturer of technical ceramics. Products include both controlled porosity and densely structured ceramics designed to meet requirements specified by our customers for durability, chemical, corrosion and wear resistance, toughness, and density.

Porous Ceramic Filters are used for solid particulate removal in liquid and gas applications as the filter media in chemical process, petrochemical, semiconductor, food & beverage, and pharmaceutical industries. Porous ceramic filters are commonly referred to as filter stones, ceramic elements, candle filters, ceramic tubes and ceramic cartridges.

The range of Refractron porous ceramic filters are made from aluminum oxide and silicon carbide. The strong, uniform porous ceramic with a tortuous structure has 40-50% open porosity and is available in pore sizes ranging from 0.25 to 90 microns. Monolithic, single grade, aluminum oxide porous ceramic is available in 6, 15, 30, 50, 60 and 90 micron pore sizes. In addition, Refractron produces a ceramic membrane that uses a medium pore substrate with a thin coating of fine porous ceramic membrane in 0.25, 1, 3 and 6 micron pore sizes. Non destructive permeability and bubble point testing is performed to verify pore size and filter rating..

Aluminum oxide is the most standard material and has a maximum operating temperature of 1400 F (800 C). Silicon Carbide is more of a special order material for more aggressive applications and has a maximum operating temperature of 1800 F (1000 C) and has excellent thermal shock resistance.

Both of these porous ceramic materials are resistant to solvents and have good acid resistance with the exception of hydrochloric and phosphoric acids. The advantages of porous ceramics are that they are not only mechanically strong but inert and can be cleaned and reused in many process applications. Porous ceramic is used in tough applications to replace porous metal or as an alternative to plastic or fabric media. Porous ceramic is cleaned and reused using a variety of methods depending on the contaminant to be removed. Specifically tailored techniques include spraying, brushing, backwashing, oven firing, dilute acid cleaning, solvent cleaning plus steam and ultrasonic cleaning.

Porous ceramics are readily machinable using conventional diamond cutters and wheels. Since it is not ductile and the granules are removed the porous ceramic pore structure is not affected by cutting and grinding. Typical diamond tile saws are routinely used to cut porous ceramic tubes and test coupons.

The range of porous ceramic filters include membrane and monolithic tubes, discs, plates and other components made from aluminum oxide and silicon carbide where tightly controlled pore size and porosity is critical. Common filter applications where porous ceramic are used for their corrosion and temperature resistance include: pre-filtration, catalyst recovery, hot gas candles, final filtration, liquid backwash, solvent filtration, air & ammonia filters for nitric acid production, permanent filter media, filter probes, breather-vent filters, coalescing, polishing filters and solids recovery in chemical process, water, food and beverage, semiconductor processing, pharmaceutical and mining industries. Other specialty products include a range of adsorbent filter/drier cores for refrigeration applications, dispersion parts, vacuum chucks, inkpads and gas probes.

Standard cartridge, tube and candle sizes include: 2 ½”, 2 ¾”, 4 ¼” OD x up to 48” Long and they are produced to order in styles with both ends open or with flanges and closed ends (for the 2 ½” size). We have also produced porous ceramic under drain filter plates in 6” x 12” and 12 inch square sizes.

We work closely with our customers to define their needs and requirements of each specific filter application. Our engineering and sales team is great at attacking technical design and process problems, then customizing an innovative solution using our broad range of advanced industrial ceramics. Contact us with your filter application requirements.