Venting about enclosure design
Considerations for enclosure design include protection against moisture or contaminants from environmental conditions, such as heavy-duty washdowns or exposure to temperature or pressure differentials.
By Control Engineering Staff
Gore Membrane Vents are said to withstand up to 1,500 psi washdown.
Considerations for enclosure design include protection against moisture or contaminants from environmental conditions, such as heavy-duty washdowns or exposure to temperature or pressure differentials. Hermetically sealing enclosures provides safety and security but is expensive and limits access, compared to alternatives. Potting compounds can provide a remedy, but these also add cost and prevent access for upgrades or repairs. Gaskets can seal and waterproof enclosures, but wear over time and, even with a good design, can fail with improper use. Vents provide a seal and equalize interior and exterior pressure, help prevent condensation, allow evaporation, and, when batteries are in use, permit escape of explosive gases that may form if overcharging occurs.
Because, like gaskets, vents can create leaking problems over time, material selection is important for vent design, according to W.L. Gore & Associates. Gore recommends using vent made from a semi-permeable membrane. It makes vents from microporous expanded polytetrafluoroethylene (ePTFE) to protect against bugs, cleaning chemicals, and other potential contaminants, while allowing air and gases to pass in or out. Gore Membrane Vents, for example, have ratings up to IP69K, for 1,500 psi washdown.
Safeline Inc., supplier of metal-detection equipment for food and pharmaceutical industries, began using the Gore vents in 2000. ''The Gore vents provide an alternative solution to desiccant packs and don’t need replacing,'' says Oscar Jeter of Safeline. ''They provide the results we are looking for.'' Other diverse applications include military laptop computers for desert use, ski goggles, broadband communications systems, and police radios.
Gore Membrane Vents meet requirements of International Standard IEC 529 and molded parts comply with IP Code IP68 and IP69K. Vents come in a range of sizes and ratings and are available as screw-in or snap-in molded parts. Unobtrusive adhesive patches are available; these meet the IP67 standards. Vents can also be custom designed to meet customer specifications.
Gore says it began use of expanded PTFE in membrane filtration more than 26 years ago.
For more information from the Gore Web site, click here .