wrote in message
...
I made up a little cylindrical reservoir that is pressurrized by a
piston. I tried the injector with some oil that was thicker than the
lube I intend to use. The result was oil that just dripped from the
injector. An online look at DIY injector service made me wonder if the
filter was restricting the flow so I removed the filter. Then, using
oil thinned to the approximate viscosity of the real lube, I tried the
injector again. It squirted pretty good at 30 PSI. The next thing to
address is the reservoir. I'm not sure if a piston sealed with an
O-ring is the best solution for applying pressure. There might be
stiction of the O-ring so that the piston may not move smoothly enough
causing erratic fluid delivery.

If its a lubricating fluid,a nd the o-ring is of a material suitable to work
with teh fluid it should work fine. Of course you need to size the o-ring
groove properly for "just enough" o-ring engagement. I use o-rings for low
pressure injection of plastisol (10-30 PSI maybe), and for high pressure
retention of air (4500 PSI). Anyway, if you are worried about stiction you
can go to a chrome lined hydraulic tube, but I use bare aluminum tube for a
lot of applications. Low pressure air cylinders, plastisol injector, etc.
Will a piston be controllable and do the job?

An inflatable bladder would probably
work well but I have no idea where to get something like that. I'll
have to see if there is some sort of cup seal that would work better.
In any case I don't think it's a good idea to have the lube exposed to
the shop air, even though it's filtered, because there will always be
a little moisture in the air. When I need pristine air I do have a
nice refrigerated air drying system with particle filters but I don't
generally use it.

I switched my entire shop air distribution over to my refrigeration air
drier and I really like it. I have filter seperators before and after with
filter seperators on each CNC machine as well, but my main concern is water,
not the miniscule amount of other stuff that might get in.


The other thing I need to chnage is the spray
pattern. Not sure how that's gonna get done yet. Maybe just a
deflector slipped over the injector will work well enough and that's
my first option. I've got a 555 timer system running and I will be
weighing the oil squirted out once I have the pattern deal figured
out. Once that's done then the timing can be set. I'd like to have
some sort of knob to turn that has a linear relationship to the amount
of fluid delivered. So that a setting of 4 would be twice as much
fluid delivered as a setting of 2.
Eric

Once you get your 555 circuits figured out (two of them probably) you just
need two linear pots to control them.