Polytetrafluoroethylene (PTFE) membranes being filter cartridges for the separation of biomolecules in biopharmaceutical production; membranes being liquid or gas-and-liquid filtering units for industrial and domestic use in food and beverage, wine, beer, vinegar, dairy, fruit juice and edible oil production, and for producing potable water for domestic use; membranes being liquid or gas-and-liquid filtering units for industrial use in wafer, printed circuit, and photoetch production; membranes being liquid or gas-and-liquid filtering units for industrial use in the fields of organic synthesis, the production of acids and alkali, and waste treatment; membrane contactors and separators for the cleaning and purification of gases and liquids, namely, membrane distillation, desalination, degassing and debubbling; membrane contactors for liquid or gas and liquid separation , namely osmotic distillation and ozone dispersion in water; membrane separators for isolating gases from liquids namely motionless ozone check valves being parts of ozone sanitizers for air and water; ozone sanitizers for air and water; component parts sold as integral components of membrane liquid or gas-and-liquid filters and membrane contractors, namely, elastomeric, thermoplastic, and thermoset potting compounds, housings and bonding compounds that holds the bundled ends of hollow fibers together, establishing a leak proof seal between the open ends of the hollow fibers and their outside surfaces; all of the foregoing not for medical products directed to patient use