PurtrexÔ Depth Filters

Wincross is a purveyor of Osmonics® filters. Osmonics® has extended its patented blown microfiber technology to meet the market requirements for a pure polypropylene depth filter with exceptional dirt-holding capability. This translates to longer life, and fewer changeouts than existing string-wound or resin bonded filters. The resulting product - Purtrex™ - is an exceptional value for general applications where long life, high purity and low changeout frequency are required.

Purtrex filters are free from antistatic agents and binders eliminating the need for pre-rinsing. Purtrex provides clean, foam-free filtrate because it is made of 100% polypropylene. No pre-rinsing saves labor and downtime and increases production time.

Under pressure, unbonded strings can separate and create channels for particles to pass through. Purtrex polypropylene fibers are thermally-bonded to keep particles trapped in the filter, even under pressure. Purtrex delivers a filtrate of consistent quality over its entire lifetime preventing upsets in downstream processing.


Effective lifetime is the length of time the filter functions satisfactorily. The end of lifetime is determined when the pressure differential reaches 40 psid (2.8 bar). Excessive pressure drop may cause filter failure and the release of  particles into the filtrate. Because Purtrex is made from thermally-bonded fibers using a continuous process, it maintains a consistent lifetime ending at 40 psid (2.8 bar). String-wound filters are produced individually without bonded fibers. They release particles under varying pressures and perform inconsistently.

Purtrex depth filters are constructed of 100% polypropylene fibers which have wide chemical compatibility. String-wound filters contain a core, string, antistatic agent, and may contain binders or resins. These additives can complicate process compatibility and filter disposal. Purtrex filters can be compacted or incinerated to trace ash for easy disposal.

When the time comes to replace your filters, there is no need to count strings or rely on your memory. Purtrex filters are clearly labeled so you know what you're installing.