There are three different filter cartridge styles that offer different types of filtration for diverse applications. Cord wound filters, also referred to as depth filters, are a one-piece filter with hundreds of diamond-shaped tunnels that get narrower as the liquid travels from the outside of the cartridge to its core (an example from Pentek is the WP5BB97P cartridge: http://reservefilter.com/watershop/product.php?id_product=271). Particles in the liquid are progressively trapped as it travels through the tunnels, which enables this type of filter to trap many different particle sizes and leads to an excellent particle retention capacity. Applications where cord wound filters are commonly used are as pre-filters for reverse osmosis filter systems (for more on reverse osmosis filters: http://reservefilter.com/2012/06/20/new-reverse-osmosis-system-and-its-features-and-benefits/) electroplating and coating, photo processing, food and beverage uses, and oil and paint filtering.
Pleated filter cartridges contain a thin sheet of filter media that traps particles on its surface. This type of filter is typically a durable cellulose and polyester blend (like our ECP series of cartridges: http://reservefilter.com/watershop/product.php?id_product=255 ), or a synthetic polypropylene or polyester material (used in our R30 http://reservefilter.com/watershop/product.php?id_product=517 and R50 http://reservefilter.com/watershop/product.php?id_product=518 cartridges). The accordion-shaped filter media offers more surface area than cord wound filters, giving them more capacity for filtering particles of a uniform size. The fully synthetic version of this media also offers chemical and bacteria resistance, which makes these cartridges ideal for most light industrial and well water applications. This allows the cartridge to be cleaned and reused when used to filter larger particles in some applications. They are often used as a pre-filter for drinking water systems, and as filters for electroplating, etching, and image development in the circuit board industry. They are also ideal for filtration of recycled water for general manufacturing processes, as well as filtration of other low and medium viscosity fluids.
A third type of filter is a polypropylene graded density cartridge, such as the Pentek DGD series of filters (http://reservefilter.com/watershop/product.php?id_product=260). These are ideal for removal of sediment, sand, clay, and iron particles, and are often used before a water softener or iron filter system as a pre-filter to protect the equipment. The cartridges are made of melt-blown polypropylene fiber, which is thermally bonded and fused, requiring no center support core so nothing gets in the way of filtration. The filter medium in polypropylene graded density cartridges gets less porous as liquid passes through it, trapping progressively smaller particles. This type of filter has a high dirt-holding capacity, making it ideal for dealing with large particles that might easily clog other filters. Graded density filters are best used in food and beverage, pharmaceutical, light commercial and industrial, and well water filtration applications.
Whatever your needs are, Reserve Filter probably stocks it, and can make expert recommendations to get you the results you need at a price you like. Call us at 1-800-553-2777, or visit us online at www.reservefilter.com.