On Sunday 09 October 2016 12:07:47 MC Cason wrote: > Gene, > > Inline > > On 10/09/2016 01:37 AM, Gene Heskett wrote: > > On Sunday 09 October 2016 01:22:28 MC Cason wrote: > >> 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 > > > > In terms of either passive or thru flow, I have a small filter full > > of color phase changing silica gel that I use in front of my air > > brush when I've air brushing a cabinet finish. I wonder how one of > > those would work as an inlet air dryer? > > > > They aren't that expensive, and I've baked this one out in the > > microwave several times after it turned pink. It takes several days > > of active use feeding the air brush with just enough air ( 7 or 8 > > psi )to lay on a 3 part finish similar to Sam's (Sam Maloof) Stuff > > except I don't use boiled linseed, but teak oil as the 3rd part. > > Dry's dust free in a couple hours. > > > >> 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). > > > > True about cheap, good particulate stopper after the desicant > > treatment maybe? > > > > Going back to my broadcasting experience, we tended to frown on the > > desiccant to make dry air. 10 years later you can tell the diff > > between dry air for the 3 psi or so pressure in the transmission > > lines to the antenna. Dry nitrogen is the real stuff, copper is > > still bright and shiny on the inside after 20 years, but thats north > > of a hundred dollar bill for a t2 sized refill. Leakage there will > > cost real money. But plain dry air should outlast both me and those > > bellows. As for the source of the compressed air, I am inclined to > > put a cig lighter compressor in, switched on by a furnace draft > > safety switch running a relay big enough to run the compressor for 3 > > seconds an hour. Or something along those lines. It won't run long > > enough or at a high enough pressure to squeeze the water out of the > > air, and that dessicant cartridge should catch 90% of that if the > > humidity goes to 100%. I have a humidity monitor out there, and > > can't recall ever seeing it above 77% when it was pea soup foggy > > outside. > > > > This is in a heated and air conditioned environment. > > I see what you want to do now, but I don't know if blowing the > bellows up like a balloon, and trying to maintain a small positive > pressure on it would work. If it was practical, you would see more > commercial systems using it. > > It never hurts to check, but unless the seal is shaped to fit the > ball groove in the shaft, the groove would act as a significant leak. > If you have a flow meter for either Argon, C02, or mix gas, you could > use that to tell how much leakage you have. Run the nut to one end of > the shaft, and tightly duct tape a hose to one side of the nut, > leaving a small pocket around the shaft. Slowly turn on the gas, and > see if there is any measurable flow.
You are assuming I want to seal te nut, and I don't, In fact, the center hole of the nut carrer in each end pattern of 3, will be bored all he way thru with a 1/4" bit, to allow the trapped air free passage around the nut as it moves back and forth. I am more concerned with maintaining a few inches of water pressure inside the whole assembly as measure with a water (or colored oil) fluid manometer. These bellows are perhaps a few inches short too, so may be stretched two or 3 inches beyond their intended travel range, and will be about fully compressed at the other extreme. I'll have about a foot between the nipples when the saddle is under the spindle with an adapter collet in place of the chuck, but a foot is not even full compression, The bellows of the right side of the nut however will be a bit over extended when the saddle is under the spindle, and conversely when the saddle is under the tailstock, the left bellows will be slightly overstretched, while the right one will be about fully compressed. Getting under the tailstock when its at the end of the bed will need some force as the lip of the bed has been damaged by the saddle clamp wearing on it because that bolt has beeb pulled tight so forceable the bolt was bent and the was no fully released state without remove it and the clamp plate completely. Nother story below. So look at it as a sealed assembly, with any leakage being thru the end support bearings. That saddle clamp on the right has been removed, as has the mini-tab on the left, the combination intended to serve as the front gib but werte so small the wear rate was high on both the steel tabs and the bottom of yje bed lip for about 3/16" which is as far under the bed lip as they reached. With the apron with all its monkey business gone as I am useing a slab of 1/2? 7078 t6 to mount the x motor nd anchor the z nut to the saddle I will gain some compression room for the right bellows as the nut will be anchored near the left edge of this plate, adding that offset to the right bellows compression room, while pulling it pretty hard when the saddle is under the spindle nose. I was free to bore a 1/4 28 hole about every inch in the castings lip adjacent to the bed, and fit a brass, full length gib there that is reaching under the bed lip about 5/8", and the shim I fit to adjust it is just tight enough that its dragging on the paint, which I wasn't able to fully remove even with acetone and a file. It is however, wearing away, so it will pass eventually. > Saying all this, Assuming that you have 2 sets of bellows, one for > each side of the nut. A sealed system with a bit of tubing that goes > between the ends of each set bellows, would be a much simpler system. > You would simply be transferring air from one side of the nut, to the > other, without worrying about forcing air through it. No tubing, useing the center of the 3 bolts in each side of the nut flange as 1/4 thru holes, 4 bolts being enough to mount the nut solidly. > If you still intend to use positive pressure, an aquarium pump with > a small check valve, would be a easier, cheaper, and quieter, > alternative to a tire air compressor. It would also use an ordinary > wall plug, instead of using more power off of your power supply. I have one of those, but its intended to pump the water, noisy as can be dry, dead silent when wet. I use it as the coil cooling pump for one of those $40 1kw Chinese induction heaters. But you're correct in its being the best solution, so I'll see if I can find one of those, the smaller the better. Just leave it run when the machine is powered up, with a painting dessicant filter followed by a small engine fuel filter, fed into the confines of the screw I am sealing up. I must be getting old, I didn't think of that at all. Oh wait, I just turned 82 so I guess I am "old". :) > Using silica gel would work, but it goes back to maintenance. you > would be maintaining it from now on. Thats easy, stick it in the microwave when it turns pink. And even when its starting to turn colors, the air passing by will still be drier than room air. That should reduce the dew point well below ambinet because the garage is well insulated and heated/air conditioned. I keep it t shirt comfy all the time. > There is no guarantee on how > much moisture that gets remove form the airstream. The percentage of > water that gets adsorbed is dependent on how much surface area that is > available to the incoming air stream, and the volume of air passed > over it. The systems I'm familiar with, used large flat pans to > adsorb the moisture. After it adsorbed a certain percentage of > moisture, the desiccant was replaced, and recycled by heating for a > couple of hours. You don't want the desiccant to become filled with > moisture, because it's efficiency goes down, as the level of water > adsorbed goes up. Yours turning pink when saturated, means that it is > doped with cobalt chloride. This makes it easier to tell when it > needs regeneration, but makes it a bit toxic to work with. I wasn't aware of that, and have been drying the stuff in the stations microwave for decades. And of course I rinsing the dust out of a big glass bowl before I put it back in the cupboard to hold tater salad at the next station holiday doings. Enough for 40-50 people. Whats this toxicity do to humans? > I'm familiar with dry nitrogen systems, and it would be ideal, but > impractical. Even with a 300CF tank, you would be replacing it every > couple of weeks or so. For dry nitrogen, 4-9's, or 5-9's pure > nitrogen will cost significantly more than ordinary 3-9's gas, which > can still be a bit wet. I have always wondered about the possibility > of hacking a medical oxygen generator to collect the nitrogen and C02 > that it normally throws away. But, even that would need additional > conditioning to remove the water, and increase it's purity. Before I > became disabled, the last place I worked, we used 2 rail cars of > compressed nitrogen weekly. Not an insignificant cost. Many years > ago, when I worked in Silicon Valley, the nitrogen we used was brought > into the buildings via a 6" pipe, connected to the pipeline under the > street. The infrastructure used was similar to the way that natural > gas is delivered. Interesting, thanks for sharing. Thanks MC Cason. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
