With a pore size of 1.2 µm, oleophobic and hydrophobic membranes GN 7404 provide reliable aeration and ventilation, allowing no dirt particles or droplets of oil or water to pass through the membrane.
To compensate for pressure differences in both directions, JW Winco already offers various aeration and ventilation elements with integrated filters and sieves. As a new change to its product line-up, JW Winco now also offers elements equipped with membranes alongside these standard parts. This makes it possible to prevent even smaller particles and, above all, oil and water droplets from passing through the ventilation openings. Dirt and moisture are kept away from the inside of the housing, and lubricants such as oils cannot escape. While the previous filter and sieve elements have a minimum mesh size of 100 µm, the standard membrane pores are only 1.2 µm in size.
Externally, the robust membrane is additionally protected against mechanical stress by a protective sieve made of stainless steel. Ideally, the standard part GN 7404 should be installed in vertical surfaces so that no liquids can collect on the membrane, which could impair the pressure balance. At a nominal differential pressure P1 to P2 of 1 bar, the maximum air flow — depending on the diameter — is up to 34 l/min. The membrane even retains its function up to an external pressure differential of 2 bar or an internal pressure differential of up to 10 bar. The maximum operating temperature is 100 °C.
The membranes themselves are made of a nylon fleece impregnated with an acrylic copolymer, and although the fibers are wetted, the porosity remains unchanged and can range between 0.2 and 10 µm if desired.
Using a special process, the membrane is robustly bonded to a plastic ring socket by injection molding so that it can be firmly inserted into the stainless steel or aluminum screw fittings, sealed by an O-ring.