2011

Technology Eliminates the Need for Pre-Wetting Cartridge Filters

This ePTFE membrane remains hydrophilic even after exposure to steam autoclave cycles and corrosive chemicals.

There has been a long-term need in the filtration industry — particularly for a variety of life science applications — to eliminate the need for pre-wetting cartridge filters with alcohol before sending them to customers. It is not only an expensive, time-consuming process, but it also increases the risk of bacterial contamination.

altShipping ePTFE hydrophilic membrane without the costly step of pre-wetting helps reduce the risk of bacteria growth during storage. Medical OEMs would benefit from a membrane that remains hydrophilic even after exposure to steam autoclave cycles and many corrosive chemicals.

The patent-pending Aspire hydrophilic ePTFE membrane was developed to help improve the performance and reliability of sensitive devices. It meets the same criteria for bacteria retention, flow rate, and chemical resistance as hydrophobic ePTFE membranes, while supporting extremely low extractables and lasting hydrophilic characteristics.

The results: elimination of the pre-wetting process, which can account for up to 40 percent of a customer’s cost per cartridge. Doing so also reduces the environmental impact of the alcohol waste stream. For medical end users, the membrane can hold up during liquid microfiltration even after exposure to steam autoclave cycles, many corrosive chemicals, and other severe conditions.

Aspire hydrophilic membranes can be used in cartridges serving a variety of life science applications, including pharmaceutical production, food and beverage manufacturing, and laboratory testing. In the past, hydrophobic ePTFE membranes and their inherent need for prewetting were not compatible with the cleanliness requirements for life science applications. The 0.2 μm pore size in this hydrophilic membrane has been tested for bacterial filtration efficiency and meets the criteria in flat sheet for sterile filtration.

Developing the laminate took a year of research from teams at GE’s Global Research Center in upstate New York and also GE’s Filtration Technologies headquarters in Kansas City, MO. Testing shows the new hydrophilic membranes were instantly wet with water after three autoclave cycles at 130 °C. They also maintained water wettability and water flow after 24-hour exposure to chemicals such as 0.1N hydrochloric acid, 0.1N sodium hydroxide, dimethylformamide, acetone, isopropanol, and water at 40 °C.

The new membranes and laminates also exhibit several other features and benefits, including: enduring hydrophilic properties; extremely low extractables capabilities; high stability in pore size and strength; good resistance in high temperature applications; inherent ePTFE membrane properties; similar performance to hydrophobic ePTFE membrane in regard to bacteria retention, flow rate, and chemical resistance; maintained filtration integrity (because there’s no need to flush the membrane of pre-wetting chemicals); and reduced problems with shelf life because the filters are stored and shipped dry.

This technology was done by GE Energy, Kansas City, MO. For more information, visit http://info.hotims.com/34456-192 and under “offerings,” click on “Aspire Microfiltration and Venting.”