Gene, Unless you have a good air dryer, a couple of psi of compressed air will cause more problems than it's worth. On a rainy/humid day, compressed air will be wet with water. The bellows will trap the water, and raise the humidity level around the ballscrew, which will cause premature failure, due to contamination of the lubricant, and corrosion.
A cheap water separator will get part of the water out, but nowhere near all of it. A coalescing air filter can get most of the water out, but they are expensive, the replacement ceramic filters are expensive, and they require fairly constant inspection. They are used in paint shops as a final filter before the paint gun. Why not use a passive way to allow air in and out? You will still have a problem with humidity, but it will be less than with compressed air. https://amzn.com/B003Q6CBNY https://amzn.com/B008OTNGXC BTW, airplanes use air filters that look like fuel filters. Maybe a cheap fuel filter for a lawn mower could be tested to see how well it would work as a vacuum break? Attach a hose to the outlet end only, leave the inlet open to free air, and connect the hose to wherever you were planning on attaching your air hose. Depending on use, the lifespan would be on the order of months, but they are cheap, and easy to replace (Unlike an airplane). This is what a Cessna vacuum air filter looks like (NOT cheap): http://www.aircraftspruce.com/catalog/inpages/Inline_airfilter.php On 10/08/2016 10:11 PM, Gene Heskett wrote: > Greetings all; > > Does anyone know it the end bearings that come with a C7 grade Chinese > ball screw are neoprene seals or just very close fitting dust covers? > > I am attempting to come up with a SWAG as to how much leakage per hour > there might be with 1 or 2 PSIA inside the bellows. The dust cover > versions I expect the pressure would just drive out the lube in a few > days is it was high enough to stiffen the bellows noticeably. And I'd > expect I'd better fit a t so I could rig an oil filled vinyl manometer > tube off it. Something like RCA did to monitor the air pressure across > the anode fins of the high power tubes they used in the '60's comes to > mind. Anything below 14" was time to clean things, blowers and filters > first. > > Cheers, Gene Heskett -- MC Cason Eagle3D - Created by Matthias Weißer github.com/mcason/Eagle3D ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
