String wound filter cartridges utilize polypropylene inner cores as a base. This base is nominally 10" long (actual length = 9 27/32") and the final filter cartridge length fits standard 10" filter housings sold by a variety of manufacturers. MICRON also supplies 10" filter housings which utilize MICRON string wound filter cartridges.We also manufacture 5”, 7”, and 20” long filter cartridges and offer diameters from 1 7/8” to 4 5/8” in all lengths.
Special FDA compliant polypropylene filter yarn (typically called string,) is carefully wound onto the core in a specific pattern and density to meet the micron particle size requirements of that particular filter cartridge. String wound filter cartridges are referred to as “depth" filters since particulate is trapped within the full volume or “depth" of the cartridge. Fiber-wound and Melt-Blown cartridges do not perform as well as string wound cartridges because they do not exhibit a gradient filtering capability like wound cartridges. This makes wound cartridges superior with longer filter life and fewer filter changes. The lower the micron rating of the filter cartridge, the smaller the contaminating particle size it will remove from the liquid being filtered. Cartridges wound to very low micron ratings such as 1 or 5 micron utilize a phenomenon called “Van Der Walls" attraction forces to capture and hold the contaminant. Micron ratings of string wound filters are nominal (see FAQ for detail).
MICRON String wound polypropylene filter cartridges, as with any filter cartridge, will create a pressure drop in a flowing liquid system. A clean filter cartridge will create a minimal pressure drop depending on the liquid flow rate. The higher the flow rate, the higher the pressure drop. As the filter becomes clogged with contaminants, the pressure drop will gradually increase and flow will, correspondingly, decrease. Typically, a maximum pressure drop of 20 PSI is allowed for string wound filter cartridges as higher pressure drops may overcome the Van Der Walls holding forces allowing contaminating particles to release again from the surface of the polypropylene filter media. Given the strength of the polypropylene core, crushing of string wound filter cartridges due to a high clog condition is almost non-existent at low operating temperatures. At higher temperatures, collapsing may occur at about a 50 to 70 PSI pressure drop.
MICRON Activated Carbon Filter Cartridges incorporate an inner layer of high performance activated carbon mesh which is wound next to the filter core. On top of this layer, we wind a 1 micron polypropylene filter media outer layer which provides a pre-filtration protection to the activated carbon, keeping any small sediment particles out of the carbon which keeps the carbon clean, allowing it to absorb bad tastes and odors at maximum efficiency. Used in conjunction with a MICRON string wound polypropylene pre-filter, water sediment is removed and odors are reduced. Our activated carbon filter cartridges are also economical as compared to carbon block and other carbon filter cartridges. MICRON Activated Carbon Filter Cartridges are available in 10” and 20” lengths, 2 ½” and 4 ½” diameters.
Typical flow rates for string wound filter cartridges vary from 3 Gallons Per Minute (GPM) for cartridges rated at 1 micron to 6 GPM for cartridges rated at 50 micron. The larger the micron rating, the larger the filter pores, which allow for higher flow rates.
Safe operating temperatures for polypropylene filter cartridges are up to 140° F. MICRON recommends operating temperatures be kept below 140°F to maintain a margin of safety.
MICRON polypropylene filter cartridges are compatible with a wide variety of liquids to be filtered, including, but not limited to:
Acetic Acid
Caustic Soda
Potable Water
Compressed Air
Citric Acid
Milk
Alcohol
Diesel Fuel
Mineral Oil
Cane and Beet Sugar Liquors
Fruit Juices
Salt Water
Carbonated Water
Glycerin
Vinegar
Bio Diesel Fuels
Contact Us for a complete chemical compatibility listing.
