A wide range of sizes and formats are available from circular in shape to custom panels made to fit a particular aperture.
If required, shielded vents may be supplied fitted with an air filter panel or a kick-plate. This can be easily removed, leaving the vent in place, cleaned and replaced. An open structured or de-membraned polyurethane is usually used as the air filter media. Obviously, the addition of an air filter to any vent will greatly decrease airflow or increase pressure drop.
Vents can include a kick plate to offer some protection to the honeycomb if mounted in a position where it is likely to be subject to occasional unintentional contact.
There are two basic frame styles available, either a ‘U’ channel or an equivalent section that incorporates an external flange that allows a vent to sit within an aperture if required. Vents can be pre-drilled with through holes, or ready to mount with threaded inserts/fasteners.
So as to provide appropriate low impedance interface vent are normally supplied fitted with knitted mesh gaskets or knitted mesh/sponge elastomer combination gaskets if a degree of environmental sealing is required as well. Other gasket types may be used in certain circumstances e.g. finger strip.
Up until recent times, the default surface finish or treatment was a chromate conversion coating, usually described as ‘light iridescent yellow’ or ‘transparent/clear’. These coatings improve the corrosion resistance of the vent and allow reasonably low contact resistance, particularly in the case of the transparent version of the coating. These are becoming less acceptable as they contain hexavalent chromium (or Cr+6) that is controlled by RoHS (Restriction of Hazardous Substances) legislation. We can now offer vents that have an equivalent surface treatment that is fully RoHS compliant but still meets the specifications that were originally developed around chromate conversion coatings, such as Mil-C-5541E.
Vents may also be supplied with plated finishes such as nickel or tin over nickel that can enhance EMC shielding performance by improving connectivity over the vent as well as lowering surface contact resistance at the gasket interface.
If vents are to be used in wet or hostile outdoor environments then they may be over-painted, even after fitting to the enclosure. We can supply vents painted (or otherwise finished) to your specification and even include labels or printed part numbers, markings or engraved and infilled detail. In some cases, it may be advisable to fit a separate louvred cover to prevent direct weathering.